Measurements of Zγ+jets differential cross sections in pp collisions at √s = 13 TeV with the ATLAS detector

JHEP07(2023)133 Published for SISSA by Springer Received:December 20, 2022 Revised:February 15, 2023 Accepted:March 8, 2023 Published:July 17, 2023 Search for dark photons from Higgs boson decays via ZH production with a photon plus missing transverse momentum signature from pp collisions at √s= 13 TeV with the ATLAS detector The ATLAS collaboration E-mail: [email protected] Abstract: This paper describes a search for dark photons (γd) in proton-proton collisions at √s= 13 TeV at the Large Hadron Collider (LHC). The dark photons are searched for in the decay of Higgs bosons (H→γγd) produced through the ZH production mode. The transverse mass of the system, made of the photon and the missing transverse momentum from the non-interacting γd, presents a distinctive signature as it peaks near the Higgs boson mass. The results presented use the total Run-2 integrated luminosity of 139 fb−1recorded by the ATLAS detector at the LHC. The dominant reducible background processes are estimated using data-driven techniques. A Boosted Decision Tree technique is adopted to enhance the sensitivity of the search. As no excess is observed with respect to the Standard Model prediction, an observed (expected) upper limit on the branching ratio BR(H→γγd) of 2.28%(2.82+1.33 −0.84%) is set at 95%CL for massless γd. For massive dark photons up to 40GeV, the observed (expected) upper limits on BR(H→γγd)at 95% confidence level is found within the [2.19,2.52]%([2.71,3.11]%) range. Keywords: Hadron-Hadron Scattering ArXiv ePrint: 2212.09649 Open Access, Copyright CERN, for the benefit of the ATLAS Collaboration. Article funded by SCOAP3. https://doi.org/10.1007/JHEP07(2023)133 JHEP07(2023)133 Contents 1 Introduction 1 2 The ATLAS detector 3 3 Data samples 4 4 Simulated event samples 5 4.1 Signal samples 5 4.2 Background samples 7 5 Event reconstruction and selection 9 5.1 Event reconstruction 9 5.2 Signal region selection 10 6 Treatment of the background processes 13 6.1 Evaluation of the background from electrons faking photons 14 6.2 Evaluation of the background from fake Emiss T15 6.3 Treatment of the irreducible background and the top-quark background 17 6.4 Background checks in validation region 17 7 Systematic uncertainties 17 7.1 Experimental systematic uncertainties 17 7.2 Theoretical systematic uncertainties 19 8 Results and Interpretation 20 9 Conclusion 23 The ATLAS collaboration 31 1 Introduction There is strong astrophysical evidence suggesting the existence of dark matter (DM) with a density about five times higher than ordinary baryonic matter [1]. However, its fundamental nature is unknown and it is plausible that it is a component of a larger “dark sector”, which couples weakly to the Standard Model (SM) and possesses a rich internal structure and interactions. Existing models propose dark sectors that contain few or many particles, some providing ideal candidates for DM. The interaction of these dark states can be Yukawa-like or mediated by dark gauge bosons or both. The dark and visible sectors may interact through a portal offering a potential experimental signature. The form of this portal can be classified according to the type and – 1 – JHEP07(2023)133 dimension of its operators. The best motivated and most studied cases contain relevant operators taking different forms, depending on the spin of the mediator: vector (spin 1), neutrino (spin 1/2), Higgs boson (scalar) and axion (pseudo-scalar) [2]. The vector portal considered in this paper is the one where the interaction results from the kinetic mixing between one dark and one visible Abelian gauge boson. The visible photon is taken to be the boson of the U(1) gauge group of electromagnetism—or the hyper-charge in the regime above the electroweak symmetry breaking scale—and the dark photon (γd) is identified as the boson of an extra U(1)Dgauge group of the dark sector. This mixing is always possible because the field strengths of two Abelian gauge fields can be multiplied together to give a dimension four operator [3]. The existence of such an operator means that the two gauge bosons mix as they propagate [4]. This kinetic mixing provides the portal linking the dark and visible sectors and makes the experimental detection of the dark photon possible. Massless and massive dark photons, whose theoretical frameworks as well as experimental signatures are quite distinct, give rise to dark sectors with different phenomenological and experimental features. The massive dark photon has received so far most of the attention because it couples directly to the SM currents and is more readily accessible in the experimental searches [5–9]. The massless dark photon arises from a sound theoretical framework [2]. It does not couple directly to any of the SM currents and interacts instead with ordinary matter only through operators of dimension higher than four. It provides, with respect to the massive case, a comparably rich, if perhaps more challenging, experimental target. Looking beyond particle physics and towards cosmology, dark photons may solve the small-scale structure formation problems [10]. In astroparticle physics, dark photons may induce the Sommerfeld enhancement of the DM annihilation cross-section needed to explain the PAMELA-Fermi-AMS2 positron anomaly [11]. They may also assist light DM annihilation to reach the phenomenologically required magnitude, and make asymmetric DM scenarios phenomenologically viable [12,13]. This analysis searches for dark photons predicted by a new model generating exponentially spread SM Yukawa couplings from unbroken U(1)Dquantum numbers in the dark sector [14]. In this approach, non-perturbative flavourand chiral-symmetry breaking is transferred from the dark to the visible sector via heavy scalar messenger fields that might produce new physics signals at the Large Hadron Collider (LHC). For massless dark photons, the U(1)Dkinetic mixing with U(1) can be tuned away on shell, in agreement with all existing constraints [15,16], while off-shell contributions give rise to higher-dimensional contact operators strongly suppressed by the scale of the heavy messenger mass. A potential discovery process for dark photons proceeding via Higgs-boson production at the LHC is presented in this paper. Thanks to the non-decoupling properties of the Higgs boson, a branching ratio of H→γγdwith values up to a few percent are possible for a massless dark photon as well as for heavy dark-sector scenarios [12–14]. The corresponding signature consists, for a Higgs boson with a mass mH= 125 GeV, of a photon with an energy Eγ=mH/2in the Higgs centre-of-mass frame and a similar amount of missing transverse momentum (Emiss T) which originates from the escaping γd[13]. – 2 – JHEP07(2023)133 Figure 1. Feynman diagrams for H→γγdin q¯q→ZH and gg →ZH production modes. Moreover, in the unbroken U(1)Dscenarios, the two-body decay H→γγdcan be enhanced despite existing theoretical constraints [12], providing a very distinctive signature of a single photon plus missing transverse momentum at the Higgs boson mass resonance. If such a signature is discovered at the LHC, CP invariance will imply the spin-1 nature of the missing particle, excluding axions or other ultra light scalar particles. The photon plus Emiss Tsignature has been extensively studied by the LHC experiments [17–19]. In the particular case of massless γd, searches in Higgs boson decays were performed at the LHC in pp collisions at a centre-of-mass energy of 13 TeV. The CMS experiment has probed this decay channel using Higgs boson events produced in association with a Zboson ZH(Z→`+`−) with an integrated luminosity of 137 fb−1[20], or via vector-boson fusion (VBF) production [21] (with 130 fb−1) setting an observed (expected) upper limit on the BR(H→γγd) at the 95% confidence level (CL) of 4.6% (3.6%) and 3.5% (2.8%) respectively. ATLAS has set an observed (expected) limit on the H→γγd branching ratio, using the VBF production mode with an integrated luminosity of 139fb−1, to 1.8% (1.7%) at the 95% CL [22]. This analysis is based on the ZH production mode where Z→`+`−(`=e, µ) and H→γγd, which proceeds at leading order through the Feynman diagrams shown in figure 1. The study is performed using a final state consisting of two same-flavour, oppositecharge electrons or muons, an isolated photon and missing transverse momentum. The requirements applied to the photon and the Emiss T, originating from a potential SM Higgs boson decay, are optimised to maximise the signal acceptance. The leptons, on the other hand, are used for triggering on the event and provide a Zboson mass constraint. The transverse mass mTof the γ−Emiss Tsystem presents a kinematic edge at the Higgs boson mass and is included as a variable of interest in the boosted decision tree (BDT) score that is exploited to search for a dark photon signal. The kinematics of these events allow the search for low-mass (6= 0)γd. Hence, the analysis is optimized for dark photon searches in the [0-40] GeV mass range. 2 The ATLAS detector The ATLAS detector [23] at the LHC covers nearly the entire solid angle around the collision point1. It consists of an inner tracking detector surrounded by a thin supercon1ATLAS uses a right-handed coordinate system with its origin at the nominal interaction point (IP) in the centre of the detector and the z-axis along the beam pipe. The x-axis points from the IP to the centre of the LHC ring, and the y-axis points upwards. Cylindrical coordinates (r, φ)are used in the transverse – 3 – JHEP07(2023)133 ducting solenoid, electromagnetic and hadron calorimeters as well as a muon spectrometer incorporating three large superconducting air-core toroidal magnets. The inner-detector system (ID) is immersed in a 2 T axial magnetic field and provides charged-particle tracking in the range of pseudorapidity |η|<2.5. The high-granularity silicon pixel detector covers the vertex region and typically provides four measurements per track, the first hit normally being in the insertable B-layer (IBL) installed before Run 2 [24,25]. It is followed by the silicon microstrip tracker (SCT), which usually provides eight measurements per track. These silicon detectors are complemented by the transition radiation tracker (TRT), which enables radially extended track reconstruction up to |η|= 2.0. The TRT also provides electron identification information based on the fraction of hits (typically 30 in total) above a higher energy-deposit threshold corresponding to transition radiation. The calorimeter system covers the pseudorapidity range |η|<4.9. Within the region |η|<3.2, electromagnetic (EM) calorimetry is provided by barrel and endcap highgranularity lead/liquid-argon (LAr) calorimeters, with an additional thin LAr presampler covering |η|<1.8to correct for energy loss in material upstream of the calorimeters. Hadron calorimetry is provided by the steel/scintillator-tile calorimeter, segmented into three barrel structures within |η|<1.7, and two copper/LAr hadron endcap calorimeters. The solid angle coverage is completed with forward copper/LAr and tungsten/LAr calorimeter modules optimised for electromagnetic and hadronic energy measurements respectively. The muon spectrometer (MS) comprises separate trigger and high-precision tracking chambers measuring the deflection of muons in a magnetic field generated by the superconducting air-core toroidal magnets. The field integral of the toroids ranges between 2.0and 6.0 T m across most of the detector. Three layers of precision chambers, each consisting of layers of monitored drift tubes, covers the region |η|<2.7, complemented by cathodestrip chambers in the forward region, where the background is highest. The muon trigger system covers the range |η|<2.4with resistive-plate chambers in the barrel, and thin-gap chambers in the endcap regions. Interesting events are selected by the first-level trigger system implemented in custom hardware, followed by selections made by algorithms implemented in software in the highlevel trigger [26]. The first-level trigger selects events from the 40 MHz bunch crossings at a rate below 100 kHz, which the high-level trigger further reduces in order to record events to disk at about 1 kHz. An extensive software suite [27] is used in the reconstruction and analysis of real and simulated data, in detector operations and in the trigger and data acquisition systems of the experiment. 3 Data samples The data used in this paper were collected by the ATLAS experiment from the LHC pp collisions at √s=13 TeV during stable beam conditions, with all subdetectors operaplane, φbeing the azimuthal angle around the z-axis. The pseudorapidity is defined in terms of the polar angle θas η=−ln tan(θ/2). Angular distance is measured in units of ∆R≡p(∆η)2+ (∆φ)2. – 4 – JHEP07(2023)133 tional [28]. The corresponding total integrated luminosity is 139 fb−1. The data were recorded with high efficiency using unprescaled trigger algorithms based on the presence of single leptons or di-leptons, where electrons and muons are considered as leptons [29,30]. The trigger thresholds are based on the transverse momentum pTof the leptons and are determined by the data-taking conditions during the different periods [31], particularly by the number of multiple pp interactions in the same or neighbouring bunch crossings, referred to as pile-up. The number of pile-up interactions ranges from about 8 to 70, with an average of 34. Single-lepton triggers with low pTthreshold and lepton isolation requirements are combined in a logical OR with higher-threshold triggers without isolation requirements to give maximum efficiency. The di-lepton triggers require two leptons that satisfy loose identification criteria, with symmetric (symmetric or asymmetric) pTthresholds for electrons (muons). The di-lepton trigger complements the single-lepton trigger to recover between 3% and 3.6% signal efficiency depending on the dark photon mass points for combined Z→ee and Z→µµ final states. 4 Simulated event samples Monte Carlo (MC) simulated samples are used to model both the signal and the different background processes using the configurations shown in table 1. All the samples were generated at a centre-of-mass energy of 13 TeV. The generated events were processed through a simulation [32] of the ATLAS detector geometry and response using Geant4 [33], and through the same reconstruction software as the collected pp collision data. Corrections were applied to the simulated events so that the particle candidates’ selection efficiencies, energy scales and energy resolutions match those determined from data control samples. In addition, appropriate scale factors corresponding to the fired triggers are applied [29, 30]. The simulated samples are normalised to the total integrated luminosity, using the corresponding cross-sections computed to the highest order available in perturbation theory. The pile-up effects were modelled using events from minimum-bias interactions generated using Pythia8.186 [34] with the A3 set of tuned parameters [35]. They were overlaid onto the simulated hard-scatter events according to the luminosity profile of the recorded data (reweighting procedure). For massive γdsignal samples and the tWγ background process, the detector response was simulated using a fast parameterized simulation of the ATLAS calorimeters [36]. For the massless signal samples and all remaining background samples, the full Geant4 simulation was used. All simulated samples, except those produced with the Sherpa2.2.1 [37] event generator, used EvtGen 1.2.0 [38] to model the decays of heavy-flavour hadrons. 4.1 Signal samples The signal process of a Higgs boson decaying to a photon and an invisible dark photon (γd) was generated in the ZH production mode as shown in figure 1. Both q¯q→ZH and gg →ZH production modes were considered in order to have the full ZH crosssection of 0.884 pb [39]. Matrix elements were estimatd using Powhegv2 [40,41] with the NNPDF3.0 parton density libraries [42]. Events from the q¯q→ZH process were – 5 – JHEP07(2023)133 Process Generator ME Order PDF Parton Shower Tune Signal samples ZH, H →γγdPowheg Box v2 NLO NNPDF3.0nlo Pythia 8.245 AZNLO SM background samples V γQCD Sherpa v2.2.8 NLO (up to 2 jets), LO (up to 3 jets) NNPDF3.0nnlo Sherpa MEPS@NLO Sherpa V γEW K MadGraph5_aMC@NLO [v2.6.5] LO NNPDF2.3lo Pythia 8.240 A14 ZQCD Sherpa v2.2.1 NLO (up to 2 jets), LO (up to 4 jets) NNPDF3.0nnlo Sherpa MEPS@NLO Sherpa ZEWK Sherpa v2.2.1 NLO (up to 2 jets), LO (up to 4 jets) NNPDF3.0nnlo Sherpa MEPS@NLO Sherpa Single t-quark/t¯ tPowheg Box v2 NLO NNPDF2.3lo Pythia 8.230 A14 t¯ t(V, V V ), W tγ MadGraph5_aMC@NLO [v2.2.3] NLO NNPDF2.3lo Pythia 8.210 A14 SM Higgs Powheg Box v2 NNLO (ggF), NLO (VBF, V H, t¯ tH) PDF4LHC15 Pythia 8.230 AZNLO VVγ Sherpa v2.2.11 NLO (0 jets), LO (up to 3 jets) NNPDF3.0nnlo Sherpa MEPS@NLO Sherpa V V /V V V Sherpa v2.2.2 NLO (0 jets), LO (up to 3 jets) NNPDF3.0nnlo Sherpa MEPS@NLO Sherpa Samples for evaluating systematic uncertainties ZH, H →γγdPowheg Box v2 NLO NNPDF3.0nlo Herwig v7.1.3 H7-UE-MMHT ZγQCD MadGraph5_aMC@NLO [v2.3.3] NLO NNPDF2.3lo Pythia 8.212 A14 WγQCD MadGraph [v2.8.1] NLO NNPDF2.3lo Pythia 8.244 A14 WγEWK MadGraph [v2.8.1] NLO NNPDF3.0nlo Herwig v7.1.3 H7-UE-MMHT ZQCD MadGraph5_aMC@NLO [v2.2.3] NLO NNPDF2.3lo Pythia 8.210 A14 ZEWK Herwig v7.1.3 NLO NNPDF3.0nlo Herwig v7.1.3 H7-UE-MMHT V γγ MadGraph5_aMC@NLO [v2.7.3] NLO NNPDF2.3lo Pythia 8.244 A14 t¯ tPowheg Box v2 NLO NNPDF3.0nlo Herwig v7.0.4 H7-UE-MMHT t¯ t V MadGraph5_aMC@NLO [v2.3.3] NLO NNPDF3.0nlo Herwig v7.2.1 H7-UE-MMHT Table 1. The configurations used for event generation of signal and background processes. Vrefers to an electroweak boson (Wor Z/γ∗). The matrix element (ME) order refers to the order in the strong coupling constant of the perturbative calculation in the MC event generation. PDF refers to the parton density librairies used with the generator. The tune refers to the underlying-event tune of the parton shower model. generated at next-to-leading order (NLO) while the ones corresponding to gg →ZH were generated at leading order (LO). Pythia8.245 was used to perform the Higgs boson decay as well as the hadronisation and showering with the CTEQ6L1 PDF set and the AZNLO tune [43]. The samples were generated at a Higgs boson mass of 125 GeV, a width set to the SM value of 4 MeV [39] and the complex pole scheme [44] turned off. The Hidden Valley scenario [45] for BSM Higgs boson decay as implemented in Pythia8.150 was used to produce H→γγdsignal events. A total of six Monte Carlo samples were generated with dark photon masses equal to 0, 1, 10, 20, 30, 40 GeV. Finally, in order to increase the generation efficiency, a generator-level lepton filter was applied, requiring two electrons or muons with pT>10 GeV and |η|<2.7. – 6 – JHEP07(2023)133 4.2 Background samples The analysis is affected by a large variety of background processes. The irreducible background comes from VVγ final states (Vbeing any of W, Z) with both Vbosons decaying leptonically. The reducible background, which is dominant, comes from Emiss Tmismeasurement (fake Emiss T) — typically due to undetected particles or hadronic jets not fully contained in the detector acceptance — or from particle misidentification. For instance, an electron can wrongly be identified as a photon (electron faking photon, e γ), or an energetic neutral pion (π0→γγ) contained in a hadronic jet can wrongly be identified as a photon (jet faking photon, j γ). Moreover, a track in a jet may also be wrongly identified as a lepton, or a lepton from a heavy-flavour quark decay may appear as an isolated lepton (jet faking lepton, j `). Finally, events from top-quark production, with subsequent semi-leptonic t→W(→`ν)bdecay, contain genuine Emiss T, one or two leptons, and one or two b-jets that may fail a b-jet veto. Whenever higher-order cross-section computations are available [46–48], they are used to rescale the cross-section of the generator. Finally, a specific treatment was applied to processes with possible overlaping events in Zγ and Z+jets, V V and V V γ or in t¯ tand t¯ tγ. In order to avoid duplicated events, the overlap removal algorithm gives preference to photons produced in matrix elements (ME) over the ones from intial/final state radiations or decays. As an example, overlapping events were removed from Z+jets and kept in the Zγ process. Finally, `` final states consist of ee and µ+µ−channels and include the leptonic decay of τ-leptons. Irreducible background: these processes were generated according to the number of leptons in their final states as ``ννγ,```νγ and ````γ using the Sherpa v2.2.11 [49] event generator at NLO with up to three jets at the leading order (LO). In addition, contributions from off-shell bosons were also included. The full event was generated using NNPDF30_nnlo_as_0118 libraries and tuning developed by the Sherpa authors [42]. Zγ+ jets and W γ+ jets productions: the Z(→``)γ+jets and W(→`ν)γ+jets processes are split into two components based on the order in the electroweak coupling constant αEWK. The strongly-produced component is of order α3 EWK and the electroweak component is of order α5 EWK. The strong background processes of Z(→``)γ+ jets are modelled using filtered Sherpa 2.2.8 [37] samples. These samples are filtered by requiring a vector boson pT>90 GeV and are merged with Sherpa 2.2.8 V γ+jets samples produced with a biased phase space enhancing pT(V)and pT(γ)at high values. A photon filter was applied, with pT>7 GeV, for all the merged Z(→``)γ+ jets samples. These calculations use the Comix [50] and Open-Loops [51] matrix element generators, and merging is done with the Sherpa parton shower [52] using the ME+PS@NLO prescription [53]. The NNPDF30_nnlo_as_0118 PDF and tuning [42] is used. Matrix elements for the stronglyproduced contribution are calculated at NLO in αsfor up to two additional final-state partons, and at LO for up to three additional partons with NLO EWK+QCD corrections used as the central value for Sherpa. Matrix elements for the electroweak VBF contribution are calculated at LO in αswith five final-state partons (e.g. `+`−γjj QCD=0) in – 7 – JHEP07(2023)133 MadGraph 2.6.5. The LO interference between this electroweak and strong production samples was generated, and its cross-section is about 5% of the electroweak sample. This value is taken into account as an uncertainty on the electroweak background contribution. The showering is done using Pythia8.240 [54] and merged in the CKKW-L scheme [55]. The photon pTis required to be larger than 10 GeV, and the Frixione isolation [56] is applied to remove overlap with charged partons. Z+jets production: the modelling of Z+jets is crucial in this analysis. This background has significant systematic uncertainties, as the modelling of the Emiss Tdepends on the modelling of pile-up interactions and on the jet energy response. The Z+jets samples used are simulated using the Sherpa 2.2.1 event generator and the NNPDF3.0 NNLO libraries and the Sherpa tuning, with the invariant `` mass m`` >40 GeV. Top-quark pair and single top-quark productions: background samples for topquark pair production, as well as single top-quark, including W t production, were simulated using Powheg Box v2 interfaced with Pythia8.230 with the NNPDF2.3LO libraries and the A14 tuning was used. Both s-channel and t-channel productions are included in the single top-quark samples. The diagram removal scheme (DR) [57] is used to remove interferences and overlap between the tW and t¯ tproductions. t¯ t(V,V V ), t¯ tγ and W tγ production: background samples for top-quark pair production in association with one or two vector bosons (Wor Z) or a photon, as well as single top-quark with an additional Wand γwere simulated with the MadGraph5_aMC@NLO 2.3.3 generator [58] interfaced with Pythia8.210 with the NNPDF2.3LO libraries and the A14 tune. SM Higgs boson production: different production modes are considered as backgrounds as they can produce ffinal states with `+`−+γ+Emiss T. Higgs bosons produced in association with a Wor Zboson as well as Higgs bosons produced via gluon-gluon fusion (ggF), vector boson fusion (VBF) and ttH productions were all considered. These samples were generated using Powheg Box v2 with the NNPDF3.0 libraries and then showered with Pythia8.230 and AZNLO tuning. Di-boson production: ZZ →`+`−`0+`0−,ZZ →`+`−ν¯ν,WZ →`ν`+`−and WW → `+ν`−¯ν(`=e, µ) processes are simulated using the Sherpa2.2.2 [49] event generator with NNPFD3.0NNLO libraries in the case of qq and gg-initiated production. The gg →ZZ processes include a QCD k-factor of 1.7 which was calculated from the ratio NLO/LO of the corresponding cross-sections at 13 TeV [39]. The qq →`+`−ν¯νsamples include both ZZ and WW events. Tri-boson production: the expected contribution from this background is very minor as it is suppressed by the requirement of no more than two leptons in the final state. Tri-boson production, V V V , with V=Wor Z, is simulated by the Sherpa2.2.2 event generator at NLO with NNPDF3.0 NNLO PDF libraires and tuning. – 8 – JHEP07(2023)133 Figure 2. Regions involved in the “ABCD” method for estimation of the background from fake Emiss T; region Ais the signal region. The data-driven estimates of the background from e γin the e+e−channel and µ+µ−channel are, respectively, 21.0±2.4and 20.4±2.1events. The total uncertainty is evaluated combining in quadrature the statistical uncertainty of the ep-CR, the uncertainty on fe γand on fj e. 6.2 Evaluation of the background from fake Emiss T The data-driven estimate of the background from fake Emiss Tis achieved by means of an “ABCD method”; besides the SR (here labelled region A), three CRs (B, C, D) are defined by inverting the selection cuts on the Emiss Tand ∆φ(~ Emiss T, ~p``γ T)variables: •region A:Emiss T>60 GeV and ∆φ(~ Emiss T, ~p``γ T)>2.4 rad; •region B:Emiss T∈[30,40] GeV and ∆φ(~ Emiss T, ~p``γ T)>2.4 rad; •region C:Emiss T>60 GeV and ∆φ(~ Emiss T, ~p``γ T)<2.4 rad; •region D:Emiss T∈[30,40] GeV and ∆φ(~ Emiss T, ~p``γ T)<2.4 rad. Two more validation regions (VR) are introduced: •region A0:Emiss T∈[40,60] GeV and ∆φ(~ Emiss T, ~p``γ T)>2.4 rad; •region C0:Emiss T∈[40,60] GeV and ∆φ(~ Emiss T, ~p``γ T)<2.4 rad. as illustrated in figure 2. The regions B, C, D are built such as to be enriched in events with fake Emiss T. The residual contribution of events with genuine Emiss Tis subtracted; a large portion of them come from the e γbackground, and therefore can be evaluated and subtracted by applying the data-driven procedure described in section 6.1 to the specific regions. The other processes (VVγ, top, Wγ, and t¯ tH +V H) are estimated from simulation and subtracted. Then, the fake Emiss Tbackground in region Acan be computed as: Nfake Emiss T A=R·Nfake Emiss T B·Nfake Emiss T C Nfake Emiss T D (6.1) – 15 – JHEP07(2023)133 channel RMC R0 nominal 0.5×(Z+ jets) 1.5×(Z+ jets) R0 MC R0 data ee 1.12 ±0.11 1.15 ±0.13 1.06 ±0.08 1.09 ±0.11 1.16 ±0.06 µµ 1.24 ±0.11 1.25 ±0.14 1.23 ±0.09 1.15 ±0.11 1.18 ±0.05 Table 5. Values of Rfor the ee and µµ channels. RMC is computed from simulation, assuming a relative amount of Z+ jets with respect to Zγ + jets processes as predicted by the simulation (nominal), or changed by factors 0.5or 1.5.R0is computed using regions A0, C0instead of (A+A0) and (C+C0), to allow a comparison between simulation and data in a sample enriched by fake Emiss T. Statistical uncertainties on the simulated samples are reported. where Ris a parameter that accounts for the correlation between the variables Emiss Tand ∆φ(~ Emiss T, ~p``γ T)in the fake Emiss Tprocesses — if the two variables were independent, R= 1. The variables were chosen so as to have Rclose to 1 and to be stable when varying the requirements on each of the variables used. The value of Ris estimated from MC simulation; the dominant processes to the fake Emiss Tbackground are Zγ + jets and Z+ jets. In these processes, only few events enter the A, C regions, causing the statistical uncertainty on Rto be large; to overcome this, regions (A+A0)and (C+C0)are used instead, exploiting the stability of Rwith respect to the value of the Emiss Tcut. Moreover, the compatibility of the R-value obtained with this approach with that from A, C regions has been checked. The extracted value for: RMC =NZ(γ)+jets A+A0·NZ(γ)+jets D NZ(γ)+jets B·NZ(γ)+jets C+C0 (6.2) is displayed in table 5, for the ee and µµ channels; the quoted uncertainties are due to the statistical uncertainties on the MC simulation. The relative contribution of Zγ + jets and Z+ jets processes, and the j γfake rate occurring in the second case, are known not to be precisely modeled by MC simulation; for this reason, the contribution of the Z+ jets process has been changed by ±50% of the MC prediction, to check its impact on RMC. The result is also shown in table 5; the small variations are well covered by the statistical uncertainties, therefore there is no evidence that the amount of Z+ jets has an impact on RMC. A further check on the reliability of RMC has been carried out exploiting the two VRs A0, C0, where a similar factor: R0=Nfake Emiss T A0·Nfake Emiss T D Nfake Emiss T B·Nfake Emiss T C0 (6.3) is introduced, and computed from MC simulation and data. R0 MC is computed using Zγ + jets and Z+ jets processes, while R0 data uses event counts after the subtraction of e γ,VVγ, top, Wγ and V H background processes. The results are shown in table 5; the comparison of R0 MC and R0 data shows no significant discrepancy. As a conclusion, the evaluation of RMC is considered reliable, and is used in Equation (6.1). – 16 – JHEP07(2023)133 The data-driven estimates of the fake Emiss Tbackground in the ee and µµ channels are, respectively, 413 ±50 and 581 ±64 events. The errors are evaluated from the propagation of the statistical uncertainties of RMC and of data in the ABCD regions. 6.3 Treatment of the irreducible background and the top-quark background The irreducible V V γ background plays an important role at high values of the BDT score, which drive the sensitivity of the search; for this reason, a dedicated “V V γ-CR” is introduced, to correct the normalisation of this background (see section 8). Recalling that such a background is a pure electroweak process, to which Z(→`+`−)Z(→ν¯ν)γand W+(→`+ν)W−(→`−¯ν)γcontribute, the “VVγ-CR” has been built to be enriched in Z(→µ+µ−)W(→µν)γ, thus requiring exactly three muons, one photon and no electrons. The opposite-charge µ+µ−-pair whose invariant mass is closest to the Zmass must fulfil all `+`−kinematic cuts of the SR; to reduce the statistical uncertainty, no requirements are applied on Emiss Tand ∆φ(~ Emiss T, ~p``γ T). The purity of ZWγ events in such a CR is estimated to be 83% from simulation. To check the normalization of the top-induced background predicted by simulation, a “top-VR” has been used, enriched by such processes; it is defined starting from the selection of the SR, removing the requirements on m`` and ∆φ(~ Emiss T, ~p``γ T), and requiring at least one b-tagged jet. The purity of events with top-quark production is estimated to be 92% from simulation in such a VR. 6.4 Background checks in validation region As an overall check of the background estimates, the data-driven techniques described in section 6.2 and section 6.1 are applied in the VR A0(figure 2). The comparison between the expected background and data is displayed in figures 3and 4, showing good agreement. 7 Systematic uncertainties This section presents the various sources of systematic uncertainties affecting all levels of the analysis. They are categorised according to their origin, effects and the way they have been estimated. 7.1 Experimental systematic uncertainties The analysis is impacted by several uncertainties related to the detector resolution, inefficiencies and mis-measurements. They are grouped into the following categories: uncertainties in the luminosity, uncertainties in the trigger efficiencies and uncertainties related to the reconstruction of physics objects such as electrons, muons, jets, and Emiss T. The estimations of these uncertainties require a particular treatment as they affect the search via potential biases to the modelling of the signal and background processes in the MC simulation. These systematic uncertainties can affect both the yield and the shape of the final observable (BDT classifier response) and are included in the statistical evaluation. The uncertainty in the luminosity is 1.7% [74] and impacts the simulated yields of both the signal and backgrounds. This uncertainty was obtained using the LUCID-2 detector [75] – 17 – JHEP07(2023)133 40 42 44 46 48 50 52 54 56 58 60 1− 10 1 10 2 10 3 10 4 10 Events Data miss T Fake E γ→e Others SM total ATLAS -1 = 13 TeV, L = 139 fbs VR A', ee 40 45 50 55 60 [GeV] miss T E 0.5 1 1.5 Data/Bkg (a) 40 42 44 46 48 50 52 54 56 58 60 1− 10 1 10 2 10 3 10 4 10 Events Data miss T Fake E γ→e Others SM total ATLAS -1 = 13 TeV, L = 139 fbs µµVR A', 40 45 50 55 60 [GeV] miss T E 0.5 1 1.5 Data/Bkg (b) Figure 3. Comparison between the expected background and data in the validation region A0, as a function of Emiss T, for the ee (a) and µµ (b) channels. The background yields from “fake Emiss T” and “e γ” are estimated with data-driven techniques. The other backgrounds are obtained from simulation and have been merged together. Uncertainties shown are statistical, both for data and for simulated backgrounds, while for the data-driven backgrounds the systematic uncertainties related to the method are also included. 0 50 100 150 200 250 300 1− 10 1 10 2 10 3 10 4 10 5 10 Events Data miss T Fake E γ→e Others SM total ATLAS -1 = 13 TeV, L = 139 fbs VR A', ee 0 50 100 150 200 250 300 ) [GeV] miss T ,Eγ( T m 0.5 1 1.5 Data/Bkg (a) 0 50 100 150 200 250 300 1− 10 1 10 2 10 3 10 4 10 5 10 Events Data miss T Fake E γ→e Others SM total ATLAS -1 = 13 TeV, L = 139 fbs µµVR A', 0 50 100 150 200 250 300 ) [GeV] miss T ,Eγ( T m 0.5 1 1.5 Data/Bkg (b) Figure 4. Comparison between the expected background and data in the validation region A0, as a function of mT, for the ee (a) and µµ (b) channels. The background yields from “fake Emiss T” and “e γ” are estimated with data-driven techniques. The other backgrounds are obtained from simulation and have been merged together. Uncertainties shown are statistical, both for data and for simulated backgrounds, while for the data-driven backgrounds the systematic uncertainties related to the method are also included. – 18 – JHEP07(2023)133 for the primary luminosity measurements. In addition, systematic uncertainties resulting from effects of pile-up modeling, due to the reweighting procedure, are also considered. Systematic uncertainties are estimated for lepton reconstruction and isolation efficiencies [60,61] and for the energy scale and resolution [60]. Additional uncertainties on lepton trigger efficiencies are also considered to take into account differences between data and simulation [29,30]. For the photons, uncertainties in the reconstruction, isolation, energy scale and resolution are considered [60,76]. For jets, uncertainties related to the energy and resolution [65] as well as pile-up jet tagging [77] are all taken into account. Specific systematic uncertainties are considered for heavy flavour tagging to correct for identification efficiencies of bottom, charm and light tagged jets [78,79]. For Emiss T, uncertainties associated with reconstructed objects are propagated and included in its calculation. Additional uncertainties associated to the Emiss Tsoft term scale and resolution are independently evaluated [70]. An additional uncertainty on the shape of the BDT classifier response for the fake Emiss T-induced background (Section 6) is considered. It is meant to account for inaccuracies in the shape of the Z+jets MC events characterized by high bin-to-bin fluctuations. To reduce these fluctuations a Gaussian smoothing algorithm is applied to the Z+jets distribution and the uncertainty is obtained from the difference between this varied shape and the one corresponding to the nominal Z+jets MC distribution together with the other MC simulated processes entering the fake Emiss Tcategory. Finally, the comparison between data and MC predictions in the “top-VR” shows a discrepancy at the level of 20% for top-induced background (Section 6.3). For this reason, in the treatment of such a background, a relative systematic uncertainty of ±20% is considered. 7.2 Theoretical systematic uncertainties Theoretical uncertainties affect all simulated signal and background processes. They originate from the limited order in αsor αEW K at which the matrix elements are calculated, the matching of those calculations to parton showers and the uncertainty of the proton PDFs. The uncertainties from the variation of QCD scale and the variation of PDFs are considered for the signal and simulated background processes. Uncertainties for backgrounds entering different control (CR) and validation (VR) regions were also estimated. For the H→γγdsignal, the total ZH cross-section is calculated up to NLO precision and is provided by the LHC Higgs Cross-Section Working Group [39]. NLO electroweak corrections reduce the cross section by 5.3%. This correction has been propagated to the BDT classifier response. The corresponding systematic uncertainties are extracted from the maximum and minimum variations of the NLO corrections and amount to 0.2-0.3%. The parton shower (PS) model effects on signal processes were estimated through a comparison between Pythia8 and Herwig7 showering models. The difference between the two algorithms in each BDT classifier response bin is – 19 – JHEP07(2023)133 taken as a systematic uncertainty on the PS model and amounts to 0.4-6.0% (0.2-36%) for qq →ZH (gg →ZH). For the QCD renormalisation µRand factorisation µFscales a seven-point scale variation is considered, which amounts to varying the renormalisation and factorisation scales independently by factor of 1/2 and 2 around µto the combinations of (µR,µF)=(µ/2, µ/2), (2µ, 2µ), (µ, 2µ), (2µ,µ), (µ,µ/2) and (µ/2,µ). The effect of these variations was propagated to the BDT classifier distributions. An envelope covering differences with respect to the nominal values is taken as the systematic uncertainty. Depending on the γdmass and the BDT bin, the uncertainties from PS vary from [-4,+5]% (qqZH) to [-19,+25]% (ggZH). Finally, uncertainties related to the choice of the PDF are computed by considering the yield predictions with full ensemble of 100 PDFs within the NNPDF set. The standard deviation of this set of yields is taken as the corresponding PDF uncertainty. The uncertainties related to the αsvariations are computed by considering the difference in the yield from two αsvariations (0.1195 and 0.1165). The αsand PDF uncertainties are quadratically added and their impact varies from ±0.4% to ±1.1%. Similar approaches have also been applied to estimate theoretical uncertainties for background processes that were evaluated using MC predictions. Up and down variations with respect to nominal values for QCD (µR, µF) scales, PDF+αsand PS algorithms were considered as systematic uncertainties for V H, t¯ tH(H→Zγ), t¯ t, t¯ tV, Wtγ, single topquark, WγQCD,EWK and VVγ. Uncertainties from PDF+αsamount to a maximum up to ±10% (Wγ, single top-quark), QCD scale up to ±30% (t¯ tV ) and PS up to ±40% (Wγ, t¯ t). Finally, theoretical uncertainties associated with Zγ and Z+jets were also evaluated as contributions from these processes need to be known in data-driven background estimation. 8 Results and Interpretation To estimate the compatibility of the data with the SM expectations, as well as to extract upper limits at 95% confidence level (CL) on the branching ratio of H→γγda binned maximum likelihood fit is performed in the SR to the distribution of the BDT classifier response merging the ee and µµ channels to obtain the best sensitivity. The chosen binning in the SR is optimised to obtain the best expected sensitivity to the signal model, while also keeping low statistical uncertainties in each bin. The likelihood function is built as a product of Poisson probability functions based on the expected signal and background yields in each BDT bin of the SR and in the single-bin V V γ CR. Two free parameters are included in the simultaneous likelihood fit: the branching ratio BR(H→γγd), which consists in the parameter of interest (POI) and multiplies the signal yield and the floating normalization factor for the VVγ irreducible background kVVγ, which is constrained by the V V γ CR. The systematic uncertainties are included as nuisance parameters, which are constrained by Gaussian distributions centered at zero with width equal to the corresponding uncertainty. The dominant backgrounds, fake Emiss Tand electron faking photons are included in the fit taking the normalization from data-driven estimates described in section 6. To model – 20 – JHEP07(2023)133 BDT bin SR 0 - 0.50 SR 0.50 - 0.64 SR 0.64 - 0.77 SR 0.77 - 0.88 SR 0.88 - 0.96 SR 0.96 - 1 V V γ CR Observed 910 84 59 72 42 6 32 Post-fit SM background 910 ±29 85.5±8.7 59.9±7.3 69.7±7.8 41.6±6.1 7.3±2.0 31.4±5.4 Fake Emiss T800 ±34 72.1±8.3 45.7±6.5 53.2±7.1 27.9±6.1 2.0±1.9 2.1+3.5 −2.1 e γ21.5±2.0 3.33 ±0.62 3.75 ±0.74 6.4±1.1 5.7±1.4 1.47 ±0.25 1.24 ±0.07 V V γ 44 ±12 5.3±1.6 5.8±1.7 6.4±1.8 5.7±1.9 3.30 ±0.97 27.3±6.4 t¯ t,t¯ tγ, single t42 ±15 4.3±1.5 3.4±1.2 3.6±1.2 2.13 ±0.80 0.50 ±0.18 0.63 ±0.22 Wγ 3.3±1.5 0.39 ±0.18 1.18 ±0.55 −0.04 ±0.02 − − t¯ tH, V H 0.15 ±0.02 0.03 ±0.01 0.04 ±0.01 0.06 ±0.01 0.09 ±0.03 0.02 ±0.01 0.17+0.18 −0.17 Pre-fit SM background 900 ±120 90 ±35 65 ±27 53 ±24 35 ±22 7.8±4.4 24 ±4.7 Signal (ZH →γγd) 5.1±1.3 1.98 ±0.51 3.2±1.0 5.5±1.6 11.1±3.1 14.9±1.9− Table 6. Observed event yields in 139 fb−1of data compared to expected yields from SM backgrounds obtained from the background-only fit for the ee +µµ channel in the SR and in the V V γ CR. The total expected yields before the fit are also shown. The expected yields for the massless γdsignal are shown assuming BR(H→γγd)= 5%. The uncertainty includes both the statistical and systematic sources. The individual uncertainties can be correlated and do not necessarily add in quadrature to equal the total background uncertainty. the BDT shape in the fit, simulated events are used for fake Emiss T, while for the background with an electron faking a photon data from the probe-electron CR (ep-CR) is considered after re-scaling each event by the appropriate fake rate fe γ. The systematic uncertainties from data-driven methods are included in the fit as correlated among different BDT bins, as well as other experimental and theoretical systematic variations. Two different fits are performed. The first corresponds to the background-only fit, in which the background predictions are determined in a fit to data assuming the presence of no signal. The second configuration instead allows for the presence of a specific signal and it is referred to as the model-dependent fit. The background-only fit has been validated first in VR A0to confirm the goodness of the SM expectations and the fitting procedure. The results of the background-only fit in SR are shown in table 6, where observed and expected event yields are shown for all of the background processes considered in this analysis. The normalisation kVVγ factor is found to be 1.35 ±0.38. The pre-fit and post-fit distributions of the BDT classifier response are shown in figure 5. Post-fit uncertainties are reduced thanks to the constraints on nuisance parameters, in particular the ones related to the fake Emiss T-induced background. Pre-fit distribution of mTis also shown in figure 6, being one of the most discriminant variables entering the BDT classifier. The relative impact of each source of systematic uncertainty on the SM background estimates is summarised in table 7. The purely statistical uncertainty of simulated samples is dominant, except in the last BDT bin, varying from about 3% to 16%. The largest systematic uncertainties in the last BDT bin are related to the shape of fake Emiss Tand to the jet energy scale and resolution corresponding respectively to 18% and 13%; uncertainty due to energy scale and resolution of electrons and photons corresponds to 5.6%, while the same uncertainty for muons corresponds to 4.1%. The other experimental and theoretical systematic uncertainties have a relative impact below about 3.5% in all BDT bins. – 21 – JHEP07(2023)133 2− 10 1− 10 1 10 2 10 3 10 4 10 5 10 6 10 7 10 8 10 9 10 10 10 Events ATLAS -1 = 13 TeV, L = 139 fbs , Pre-fitµµSR, ee+ Data miss T Fake E γ VV /single tγ+t/ttt γ→e γ W H, VHtt ) d γγZH( ) 20 GeV d γγZH( ) 40 GeV d γγZH( SM total 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 BDT classifier response 0.5 1 1.5 Data/Bkg 0.96 1 BDT classifier response 2 4 6 8 10 12 14 16 18 Events (a) 2− 10 1− 10 1 10 2 10 3 10 4 10 5 10 6 10 7 10 8 10 9 10 10 10 Events ATLAS -1 = 13 TeV, L = 139 fbs , Post-fitµµSR, ee+ Data miss T Fake E γ VV /single tγ+t/ttt γ→e γ W H, VHtt ) d γγZH( ) 20 GeV d γγZH( ) 40 GeV d γγZH( SM total 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 BDT classifier response 0.5 1 1.5 Data/Bkg 0.96 1 BDT classifier response 2 4 6 8 10 12 14 16 18 Events (b) Figure 5. Distribution of the BDT classifier response in data and for the expected SM background before (a) and after (b) the background-only fit. The expectations for ZH,H→γγdare also shown for the massless dark photon (red dashed line) and for dark photon mass values of 20GeV (blue dashed line) and 40GeV (yellow dashed line), assuming BR(H→γγd)= 5%. A zoomed view of the last BDT bin with linear y-axis scale is also shown. Uncertainties shown are statistical for data, while for backgrounds include statistical and systematic sources determined by the multiple-bin fit. The lower panel shows the ratio of data to expected background event yields. 0 20 40 60 80 100 120 140 160 180 200 2− 10 1− 10 1 10 2 10 3 10 4 10 5 10 Events Data miss T Fake E γ VV /single tγ+t/ttt γ→e γ W H, VHtt ) d γγZH( ) 20 GeV d γγZH( ) 40 GeV d γγZH( SM total ATLAS -1 = 13 TeV, L = 139 fbs µµSR, ee+ 0 50 100 150 200 ) [GeV] miss T ,Eγ( T m 0.5 1 1.5 Data/Bkg Figure 6. Distribution of mTin data and for the expected SM background before the backgroundonly fit. The expectations for ZH,H→γγdare also shown for the massless dark photon (red dashed line) and for dark photon mass values of 20 GeV (blue dashed line) and 40 GeV (yellow dashed line), assuming BR(H→γγd)= 5%. Uncertainties shown are statistical for data, while for backgrounds include statistical and systematic sources determined by the multiple-bin fit. The lower panel shows the ratio of data to expected background event yields. – 22 – JHEP07(2023)133 BDT bin 0–0.50 0.50–0.64 0.64–0.77 0.77–0.88 0.88–0.96 0.96–1 [%] [%] [%] [%] [%] [%] Total (statistical+systematic) uncertainty 3.1 10 12 11 15 28 Statistical uncertainty 3.1 9.9 12 11 14 16 Fake Emiss Tshape 0.17 0.97 0.40 0.55 2.8 18 Jet Escale and resolution 0.02 3.3 2.1 0.47 2.1 13 Electron, photon Escale and resolution 0.04 0.45 0.75 0.46 1.7 5.6 Muon Escale and resolution 0.08 0.17 0.15 0.91 1.2 4.1 Fake Emiss Tdata-driven 0.50 0.28 0.18 0.04 0.40 3.5 Emiss Tsoft term scale and resolution 0.26 0.16 0.59 0.49 0.20 2.8 Electron trigger/ID/iso/reco eff. 0.01 0.10 0.10 0.01 0.17 1.0 Muon trigger/ID/iso/reco eff. 0.01 0.07 0.08 0.06 0.03 0.84 Flavour tagging eff. <0.01 0.08 0.10 0.04 0.02 0.82 Electrons faking photons data-driven 0.02 0.08 0.06 0.06 0.07 0.73 Photon ID/iso/reco eff. 0.01 0.07 0.08 0.04 0.09 0.61 Reweighting of hµiin MC simulation 0.08 0.10 0.32 0.46 0.09 0.48 Top normalization 0.08 0.06 0.06 0.02 0.09 0.13 Theoretical V V γ 0.04 0.02 0.16 0.04 0.13 0.49 Theoretical fake Emiss T0.05 0.11 0.12 0.22 0.29 0.45 Theoretical top 0.09 0.05 0.17 0.10 0.04 0.28 Theoretical Wγ 0.04 0.10 0.18 0.05 0.13 0.24 Theoretical Higgs 0.01 0.05 0.04 0.02 0.08 0.05 Table 7. Summary of the relative uncertainties in the background estimate for the BDT bins after the background-only fit. The individual uncertainties can be correlated and do not necessarily add in quadrature to equal the total background uncertainty. The event yields in data are consistent with the predicted SM background event yields, as shown in table 6. The model-dependent fit is therefore performed in order to extract upper limits at 95% CL on the branching ratio of the sought decay mode of the Higgs boson. These limits are based on the profile-likelihood-ratio test statistic [80] and CLs prescriptions [81], evaluated using the asymptotic approximation [82]. The fit is performed including the signal component of the Higgs boson production in ZH with subsequent Higgs boson decays into γand γd. The results are provided for the massless dark photon, as well as for low dark photon mass values up to 40 GeV, as shown in figure 7. The corresponding values are also reported in table 8. The observed (expected) upper limits on BR(H→γγd)is at the level of 2.3% (2.8%), for massless γdand varies slightly until mass values of 20 GeV. The mass dependence of the limits become stronger beyond that value and the observed (expected) upper limit increases to about 2.5% (3.1%) at 40 GeV. This slight increase originates from the decreasing signal acceptance due the limited available phase space in this mass region. 9 Conclusion A search for dark photon candidates arising from semi-visible Standard Model Higgs boson decay H→γγdis performed. The Higgs boson production in association with a Z(→ `+`−)boson is exploited, which benefits from a relatively clean signal and high-efficiency lepton triggers. The search uses pp collision data collected by the ATLAS experiment at a centre-of-mass energy of √s= 13 TeV between 2015 and 2018 and corresponding to an – 23 – JHEP07(2023)133 1− 10 1 10 [GeV] d γ m 0 2 4 6 8 10 ) [%] d γγ→95% CL limit on BR(H ATLAS -1 = 13 TeV, L = 139 fbs ATLAS -1 = 13 TeV, L = 139 fbs d γγ→ZH, H Observed Expected σ 1±Expected σ 2±Expected Figure 7. Observed and expected exclusion limits at 95% CL on BR(H→γγd) as function of the γdmass. The green and yellow bands show respectively the ±1σand ±2σuncertainties. mγdBR(H→γγd)95% CL obs BR(H→γγd)95% CL exp [GeV] [%] [%] 02.28 2.82+1.33 −0.84 12.19 2.71+1.28 −0.81 10 2.21 2.73+1.31 −0.82 20 2.17 2.69+1.29 −0.81 30 2.32 2.87+1.36 −0.86 40 2.52 3.11+1.48 −0.93 Table 8. Observed and expected limits at 95% CL on BR(H→γγd)for different values of the γd mass for the ee +µµ channel. The asymmetric error corresponds to the ±1σ. integrated luminosity of 139 fb−1. Data-driven techniques are optimized to estimate the main backgrounds from processes characterized by fake Emiss Tand electrons misidentified as photons, while the normalization of the irreducible background is obtained using MC simulations constrained by data in a dedicated control region. The sensitivity of the search is enhanced thanks to a Boosted Decision Tree algorithm that permits the construction of the discriminant kinematic observable. No excess of events above the SM expectation is found. Therefore, limits on the branching ratio of a SM Higgs boson decaying to a photon and a dark photon can be set. For massless γd, an observed (expected) upper limit on BR(H→γγd) of 2.28% (2.82+1.33 −0.84%) is set at 95% CL. For massive γd, the observed (expected) upper limits are found to be within the [2.19,2.52]% ([2.71,3.11]%) range for masses spanning from 1 GeV to 40 GeV. – 24 – JHEP07(2023)133 The ATLAS collaboration G. Aad 102, B. Abbott 120, D.C. Abbott 103, K. Abeling 55, S.H. Abidi 29, A. Aboulhorma 35e, H. Abramowicz 151, H. Abreu 150, Y. Abulaiti 117, A.C. Abusleme Hoffman 137a, B.S. Acharya 69a,69b,p, C. Adam Bourdarios 4, L. Adamczyk 85a, L. Adamek 155, S.V. Addepalli 26, J. Adelman 115, A. Adiguzel 21c, S. Adorni 56, T. Adye 134, A.A. Affolder 136, Y. Afik 36, M.N. Agaras 13, J. Agarwala 73a,73b, A. Aggarwal 100, C. Agheorghiesei 27c, J.A. Aguilar-Saavedra 130f, A. Ahmad 36, F. Ahmadov 38,aa, W.S. Ahmed 104, S. Ahuja 95, X. Ai 48, G. Aielli 76a,76b, M. Ait Tamlihat 35e, B. Aitbenchikh 35a, I. Aizenberg 169, M. Akbiyik 100, T.P.A. Åkesson 98, A.V. Akimov 37, K. Al Khoury 41, G.L. Alberghi 23b, J. Albert 165, P. Albicocco 53, S. Alderweireldt 52, M. Aleksa 36, I.N. Aleksandrov 38, C. Alexa 27b, T. Alexopoulos 10, A. Alfonsi 114, F. Alfonsi 23b, M. Alhroob 120, B. Ali 132, S. Ali 148, M. Aliev 37, G. Alimonti 71a, W. Alkakhi 55, C. Allaire 66, B.M.M. Allbrooke 146, C.A. Allendes Flores 137f, P.P. Allport 20, A. Aloisio 72a,72b, F. Alonso 90, C. Alpigiani 138, M. Alvarez Estevez 99, A. Alvarez Fernandez 100, M.G. Alviggi 72a,72b, M. Aly 101, Y. Amaral Coutinho 82b, A. Ambler 104, C. Amelung36, M. Amerl 1, C.G. Ames 109, D. Amidei 106, S.P. Amor Dos Santos 130a, K.R. Amos 163, V. Ananiev 125, C. Anastopoulos 139, T. Andeen 11, J.K. Anders 36, S.Y. Andrean 47a,47b, A. Andreazza 71a,71b, S. Angelidakis 9, A. Angerami 41,ad, A.V. Anisenkov 37, A. Annovi 74a, C. Antel 56, M.T. Anthony 139, E. Antipov 121, M. Antonelli 53, D.J.A. Antrim 17a, F. Anulli 75a, M. Aoki 83, T. Aoki 153, J.A. Aparisi Pozo 163, M.A. Aparo 146, L. Aperio Bella 48, C. Appelt 18, N. Aranzabal 36, V. Araujo Ferraz 82a, C. Arcangeletti 53, A.T.H. Arce 51, E. Arena 92, J-F. Arguin 108, S. Argyropoulos 54, J.-H. Arling 48, A.J. Armbruster 36, O. Arnaez 155, H. Arnold 114, Z.P. Arrubarrena Tame109, G. Artoni 75a,75b, H. Asada 111, K. Asai 118, S. Asai 153, N.A. Asbah 61, J. Assahsah 35d, K. Assamagan 29, R. Astalos 28a, R.J. Atkin 33a, M. Atkinson162, N.B. Atlay 18, H. Atmani62b, P.A. Atmasiddha 106, K. Augsten 132, S. Auricchio 72a,72b, A.D. Auriol 20, V.A. Austrup 171, G. Avner 150, G. Avolio 36, K. Axiotis 56, G. Azuelos 108,ah, D. Babal 28a, H. Bachacou 135, K. Bachas 152,s, A. Bachiu 34, F. Backman 47a,47b, A. Badea 61, P. Bagnaia 75a,75b, M. Bahmani 18, A.J. Bailey 163, V.R. Bailey 162, J.T. Baines 134, C. Bakalis 10, O.K. Baker 172, P.J. Bakker 114, E. Bakos 15, D. Bakshi Gupta 8, S. Balaji 147, R. Balasubramanian 114, E.M. Baldin 37, P. Balek 133, E. Ballabene 71a,71b, F. Balli 135, L.M. Baltes 63a, W.K. Balunas 32, J. Balz 100, E. Banas 86, M. Bandieramonte 129, A. Bandyopadhyay 24, S. Bansal 24, L. Barak 151, E.L. Barberio 105, D. Barberis 57b,57a, M. Barbero 102, G. Barbour96, K.N. Barends 33a, T. Barillari 110, M-S. Barisits 36, T. Barklow 143a, R.M. Barnett 17a, P. Baron 122, D.A. Baron Moreno 101, A. Baroncelli 62a, G. Barone 29, A.J. Barr 126, L. Barranco Navarro 47a,47b, F. Barreiro 99, J. Barreiro Guimarães da Costa 14a, U. Barron 151, M.G. Barros Teixeira 130a, S. Barsov 37, F. Bartels 63a, R. Bartoldus 143a, A.E. Barton 91, P. Bartos 28a, A. Basalaev 48, A. Basan 100, M. Baselga 49, I. Bashta 77a,77b, A. Bassalat 66,b, M.J. Basso 155, C.R. Basson 101, R.L. Bates 59, S. Batlamous35e, J.R. Batley 32, B. Batool 141, – 31 – JHEP07(2023)133 M. Battaglia 136, D. Battulga 18, M. Bauce 75a,75b, P. Bauer 24, J.B. Beacham 51, T. Beau 127, P.H. Beauchemin 158, F. Becherer 54, P. Bechtle 24, H.P. Beck 19,r, K. Becker 167, A.J. Beddall 21d, V.A. Bednyakov 38, C.P. Bee 145, L.J. Beemster15, T.A. Beermann 36, M. Begalli 82d, M. Begel 29, A. Behera 145, J.K. Behr 48, C. Beirao Da Cruz E Silva 36, J.F. Beirer 55,36, F. Beisiegel 24, M. Belfkir 159, G. Bella 151, L. Bellagamba 23b, A. Bellerive 34, P. Bellos 20, K. Beloborodov 37, K. Belotskiy 37, N.L. Belyaev 37, D. Benchekroun 35a, F. Bendebba 35a, Y. Benhammou 151, D.P. Benjamin 29, M. Benoit 29, J.R. Bensinger 26, S. Bentvelsen 114, L. Beresford 36, M. Beretta 53, E. Bergeaas Kuutmann 161, N. Berger 4, B. Bergmann 132, J. Beringer 17a, S. Berlendis 7, G. Bernardi 5, C. Bernius 143a, F.U. Bernlochner 24, T. Berry 95, P. Berta 133, A. Berthold 50, I.A. Bertram 91, S. Bethke 110, A. Betti 75a,75b, A.J. Bevan 94, M. Bhamjee 33c, S. Bhatta 145, D.S. Bhattacharya 166, P. Bhattarai 26, V.S. Bhopatkar 121, R. Bi29,ak, R.M. Bianchi 129, O. Biebel 109, R. Bielski 123, M. Biglietti 77a, T.R.V. Billoud 132, M. Bindi 55, A. Bingul 21b, C. Bini 75a,75b, A. Biondini 92, C.J. Birch-sykes 101, G.A. Bird 20,134, M. Birman 169, M. Biros 133, T. Bisanz 36, E. Bisceglie 43b,43a, D. Biswas 170, A. Bitadze 101, K. Bjørke 125, I. Bloch 48, C. Blocker 26, A. Blue 59, U. Blumenschein 94, J. Blumenthal 100, G.J. Bobbink 114, V.S. Bobrovnikov 37, M. Boehler 54, D. Bogavac 36, A.G. Bogdanchikov 37, C. Bohm 47a, V. Boisvert 95, P. Bokan 48, T. Bold 85a, M. Bomben 5, M. Bona 94, M. Boonekamp 135, C.D. Booth 95, A.G. Borbély 59, H.M. Borecka-Bielska 108, L.S. Borgna 96, G. Borissov 91, D. Bortoletto 126, D. Boscherini 23b, M. Bosman 13, J.D. Bossio Sola 36, K. Bouaouda 35a, N. Bouchhar 163, J. Boudreau 129, E.V. Bouhova-Thacker 91, D. Boumediene 40, R. Bouquet 5, A. Boveia 119, J. Boyd 36, D. Boye 29, I.R. Boyko 38, J. Bracinik 20, N. Brahimi 62d, G. Brandt 171, O. Brandt 32, F. Braren 48, B. Brau 103, J.E. Brau 123, K. Brendlinger 48, R. Brener 169, L. Brenner 114, R. Brenner 161, S. Bressler 169, D. Britton 59, D. Britzger 110, I. Brock 24, G. Brooijmans 41, W.K. Brooks 137f, E. Brost 29, L.M. Brown 165, T.L. Bruckler 126, P.A. Bruckman de Renstrom 86, B. Brüers 48, D. Bruncko 28b,∗, A. Bruni 23b, G. Bruni 23b, M. Bruschi 23b, N. Bruscino 75a,75b, T. Buanes 16, Q. Buat 138, P. Buchholz 141, A.G. Buckley 59, I.A. Budagov 38,∗, M.K. Bugge 125, O. Bulekov 37, B.A. Bullard 143a, S. Burdin 92, C.D. Burgard 49, A.M. Burger 40, B. Burghgrave 8, J.T.P. Burr 32, C.D. Burton 11, J.C. Burzynski 142, E.L. Busch 41, V. Büscher 100, P.J. Bussey 59, J.M. Butler 25, C.M. Buttar 59, J.M. Butterworth 96, W. Buttinger 134, C.J. Buxo Vazquez107, A.R. Buzykaev 37, G. Cabras 23b, S. Cabrera Urbán 163, D. Caforio 58, H. Cai 129, Y. Cai 14a,14d, V.M.M. Cairo 36, O. Cakir 3a, N. Calace 36, P. Calafiura 17a, G. Calderini 127, P. Calfayan 68, G. Callea 59, L.P. Caloba82b, D. Calvet 40, S. Calvet 40, T.P. Calvet 102, M. Calvetti 74a,74b, R. Camacho Toro 127, S. Camarda 36, D. Camarero Munoz 26, P. Camarri 76a,76b, M.T. Camerlingo 72a,72b, D. Cameron 125, C. Camincher 165, M. Campanelli 96, A. Camplani 42, V. Canale 72a,72b, A. Canesse 104, M. Cano Bret 80, J. Cantero 163, Y. Cao 162, F. Capocasa 26, M. Capua 43b,43a, A. Carbone 71a,71b, R. Cardarelli 76a, J.C.J. Cardenas 8, F. Cardillo 163, T. Carli 36, G. Carlino 72a, J.I. Carlotto 13, B.T. Carlson 129,t, E.M. Carlson 165,156a, L. Carminati 71a,71b, M. Carnesale 75a,75b, S. Caron 113, E. Carquin 137f, S. Carrá 71a,71b, – 32 – JHEP07(2023)133 G. Carratta 23b,23a, F. Carrio Argos 33g, J.W.S. Carter 155, T.M. Carter 52, M.P. Casado 13,j, A.F. Casha155, E.G. Castiglia 172, F.L. Castillo 63a, L. Castillo Garcia 13, V. Castillo Gimenez 163, N.F. Castro 130a,130e, A. Catinaccio 36, J.R. Catmore 125, V. Cavaliere 29, N. Cavalli 23b,23a, V. Cavasinni 74a,74b, E. Celebi 21a, F. Celli 126, M.S. Centonze 70a,70b, K. Cerny 122, A.S. Cerqueira 82a, A. Cerri 146, L. Cerrito 76a,76b, F. Cerutti 17a, A. Cervelli 23b, G. Cesarini 53, S.A. Cetin 21d, Z. Chadi 35a, D. Chakraborty 115, M. Chala 130f, J. Chan 170, W.Y. Chan 153, J.D. Chapman 32, B. Chargeishvili 149b, D.G. Charlton 20, T.P. Charman 94, M. Chatterjee 19, S. Chekanov 6, S.V. Chekulaev 156a, G.A. Chelkov 38,a, A. Chen 106, B. Chen 151, B. Chen 165, H. Chen 14c, H. Chen 29, J. Chen 62c, J. Chen 142, S. Chen 153, S.J. Chen 14c, X. Chen 62c, X. Chen 14b,ag, Y. Chen 62a, C.L. Cheng 170, H.C. Cheng 64a, S. Cheong 143a, A. Cheplakov 38, E. Cheremushkina 48, E. Cherepanova 114, R. Cherkaoui El Moursli 35e, E. Cheu 7, K. Cheung 65, L. Chevalier 135, V. Chiarella 53, G. Chiarelli 74a, N. Chiedde 102, G. Chiodini 70a, A.S. Chisholm 20, A. Chitan 27b, M. Chitishvili 163, Y.H. Chiu 165, M.V. Chizhov 38, K. Choi 11, A.R. Chomont 75a,75b, Y. Chou 103, E.Y.S. Chow 114, T. Chowdhury 33g, L.D. Christopher 33g, K.L. Chu64a, M.C. Chu 64a, X. Chu 14a,14d, J. Chudoba 131, J.J. Chwastowski 86, D. Cieri 110, K.M. Ciesla 85a, V. Cindro 93, A. Ciocio 17a, F. Cirotto 72a,72b, Z.H. Citron 169,m, M. Citterio 71a, D.A. Ciubotaru27b, B.M. Ciungu 155, A. Clark 56, P.J. Clark 52, J.M. Clavijo Columbie 48, S.E. Clawson 101, C. Clement 47a,47b, J. Clercx 48, L. Clissa 23b,23a, Y. Coadou 102, M. Cobal 69a,69c, A. Coccaro 57b, R.F. Coelho Barrue 130a, R. Coelho Lopes De Sa 103, S. Coelli 71a, H. Cohen 151, A.E.C. Coimbra 71a,71b, B. Cole 41, J. Collot 60, P. Conde Muiño 130a,130g, M.P. Connell 33c, S.H. Connell 33c, I.A. Connelly 59, E.I. Conroy 126, F. Conventi 72a,ai, H.G. Cooke 20, A.M. Cooper-Sarkar 126, F. Cormier 164, L.D. Corpe 36, M. Corradi 75a,75b, E.E. Corrigan 98, F. Corriveau 104,y, A. Cortes-Gonzalez 18, M.J. Costa 163, F. Costanza 4, D. Costanzo 139, B.M. Cote 119, G. Cowan 95, J.W. Cowley 32, K. Cranmer 117, S. Crépé-Renaudin 60, F. Crescioli 127, M. Cristinziani 141, M. Cristoforetti 78a,78b,d, V. Croft 158, G. Crosetti 43b,43a, A. Cueto 36, T. Cuhadar Donszelmann 160, H. Cui 14a,14d, Z. Cui 7, W.R. Cunningham 59, F. Curcio 43b,43a, P. Czodrowski 36, M.M. Czurylo 63b, M.J. Da Cunha Sargedas De Sousa 62a, J.V. Da Fonseca Pinto 82b, C. Da Via 101, W. Dabrowski 85a, T. Dado 49, S. Dahbi 33g, T. Dai 106, C. Dallapiccola 103, M. Dam 42, G. D’amen 29, V. D’Amico 109, J. Damp 100, J.R. Dandoy 128, M.F. Daneri 30, M. Danninger 142, V. Dao 36, G. Darbo 57b, S. Darmora 6, S.J. Das 29,ak, S. D’Auria 71a,71b, C. David 156b, T. Davidek 133, D.R. Davis 51, B. Davis-Purcell 34, I. Dawson 94, K. De 8, R. De Asmundis 72a, M. De Beurs 114, N. De Biase 48, S. De Castro 23b,23a, N. De Groot 113, P. de Jong 114, H. De la Torre 107, A. De Maria 14c, A. De Salvo 75a, U. De Sanctis 76a,76b, A. De Santo 146, J.B. De Vivie De Regie 60, D.V. Dedovich38, J. Degens 114, A.M. Deiana 44, F. Del Corso 23b,23a, J. Del Peso 99, F. Del Rio 63a, F. Deliot 135, C.M. Delitzsch 49, M. Della Pietra 72a,72b, D. Della Volpe 56, A. Dell’Acqua 36, L. Dell’Asta 71a,71b, M. Delmastro 4, P.A. Delsart 60, S. Demers 172, M. Demichev 38, S.P. Denisov 37, L. D’Eramo 115, D. Derendarz 86, F. Derue 127, P. Dervan 92, K. Desch 24, K. Dette 155, C. Deutsch 24, F.A. Di Bello 57b,57a, – 33 – JHEP07(2023)133 A. Di Ciaccio 76a,76b, L. Di Ciaccio 4, A. Di Domenico 75a,75b, C. Di Donato 72a,72b, A. Di Girolamo 36, G. Di Gregorio 5, A. Di Luca 78a,78b, B. Di Micco 77a,77b, R. Di Nardo 77a,77b, C. Diaconu 102, F.A. Dias 114, T. Dias Do Vale 142, M.A. Diaz 137a,137b, F.G. Diaz Capriles 24, M. Didenko 163, E.B. Diehl 106, L. Diehl 54, S. Díez Cornell 48, C. Diez Pardos 141, C. Dimitriadi 24,161, A. Dimitrievska 17a, J. Dingfelder 24, I-M. Dinu 27b, S.J. Dittmeier 63b, F. Dittus 36, F. Djama 102, T. Djobava 149b, J.I. Djuvsland 16, C. Doglioni 101,98, J. Dolejsi 133, Z. Dolezal 133, M. Donadelli 82c, B. Dong 107, J. Donini 40, A. D’Onofrio 77a,77b, M. D’Onofrio 92, J. Dopke 134, A. Doria 72a, M.T. Dova 90, A.T. Doyle 59, M.A. Draguet 126, E. Drechsler 142, E. Dreyer 169, I. Drivas-koulouris 10, A.S. Drobac 158, M. Drozdova 56, D. Du 62a, T.A. du Pree 114, F. Dubinin 37, M. Dubovsky 28a, E. Duchovni 169, G. Duckeck 109, O.A. Ducu 27b, D. Duda 110, A. Dudarev 36, E.R. Duden 26, M. D’uffizi 101, L. Duflot 66, M. Dührssen 36, C. Dülsen 171, A.E. Dumitriu 27b, M. Dunford 63a, S. Dungs 49, K. Dunne 47a,47b, A. Duperrin 102, H. Duran Yildiz 3a, M. Düren 58, A. Durglishvili 149b, B.L. Dwyer 115, G.I. Dyckes 17a, M. Dyndal 85a, S. Dysch 101, B.S. Dziedzic 86, Z.O. Earnshaw 146, B. Eckerova 28a, S. Eggebrecht 55, M.G. Eggleston51, E. Egidio Purcino De Souza 127, L.F. Ehrke 56, G. Eigen 16, K. Einsweiler 17a, T. Ekelof 161, P.A. Ekman 98, Y. El Ghazali 35b, H. El Jarrari 35e,148, A. El Moussaouy 35a, V. Ellajosyula 161, M. Ellert 161, F. Ellinghaus 171, A.A. Elliot 94, N. Ellis 36, J. Elmsheuser 29, M. Elsing 36, D. Emeliyanov 134, A. Emerman 41, Y. Enari 153, I. Ene 17a, S. Epari 13, J. Erdmann 49, P.A. Erland 86, M. Errenst 171, M. Escalier 66, C. Escobar 163, E. Etzion 151, G. Evans 130a, H. Evans 68, M.O. Evans 146, A. Ezhilov 37, S. Ezzarqtouni 35a, F. Fabbri 59, L. Fabbri 23b,23a, G. Facini 96, V. Fadeyev 136, R.M. Fakhrutdinov 37, S. Falciano 75a, L.F. Falda Ulhoa Coelho 36, P.J. Falke 24, S. Falke 36, J. Faltova 133, Y. Fan 14a, Y. Fang 14a,14d, G. Fanourakis 46, M. Fanti 71a,71b, M. Faraj 69a,69b, Z. Farazpay97, A. Farbin 8, A. Farilla 77a, T. Farooque 107, S.M. Farrington 52, F. Fassi 35e, D. Fassouliotis 9, M. Faucci Giannelli 76a,76b, W.J. Fawcett 32, L. Fayard 66, P. Federic 133, P. Federicova 131, O.L. Fedin 37,a, G. Fedotov 37, M. Feickert 170, L. Feligioni 102, A. Fell 139, D.E. Fellers 123, C. Feng 62b, M. Feng 14b, Z. Feng 114, M.J. Fenton 160, A.B. Fenyuk37, L. Ferencz 48, R.A.M. Ferguson 91, S.I. Fernandez Luengo 137f, J. Ferrando 48, A. Ferrari 161, P. Ferrari 114,113, R. Ferrari 73a, D. Ferrere 56, C. Ferretti 106, F. Fiedler 100, A. Filipčič 93, E.K. Filmer 1, F. Filthaut 113, M.C.N. Fiolhais 130a,130c,c, L. Fiorini 163, F. Fischer 141, W.C. Fisher 107, T. Fitschen 101, I. Fleck 141, P. Fleischmann 106, T. Flick 171, L. Flores 128, M. Flores 33d,ae, L.R. Flores Castillo 64a, F.M. Follega 78a,78b, N. Fomin 16, J.H. Foo 155, B.C. Forland68, A. Formica 135, A.C. Forti 101, E. Fortin 102, A.W. Fortman 61, M.G. Foti 17a, L. Fountas 9,k, D. Fournier 66, H. Fox 91, P. Francavilla 74a,74b, S. Francescato 61, S. Franchellucci 56, M. Franchini 23b,23a, S. Franchino 63a, D. Francis36, L. Franco 113, L. Franconi 19, M. Franklin 61, G. Frattari 26, A.C. Freegard 94, P.M. Freeman20, W.S. Freund 82b, N. Fritzsche 50, A. Froch 54, D. Froidevaux 36, J.A. Frost 126, Y. Fu 62a, M. Fujimoto 118, E. Fullana Torregrosa 163,∗, J. Fuster 163, A. Gabrielli 23b,23a, A. Gabrielli 155, P. Gadow 48, G. Gagliardi 57b,57a, L.G. Gagnon 17a, G.E. Gallardo 126, E.J. Gallas 126, B.J. Gallop 134, – 34 – JHEP07(2023)133 R. Gamboa Goni 94, K.K. Gan 119, S. Ganguly 153, J. Gao 62a, Y. Gao 52, F.M. Garay Walls 137a,137b, B. Garcia29,ak, C. García 163, J.E. García Navarro 163, M. Garcia-Sciveres 17a, R.W. Gardner 39, D. Garg 80, R.B. Garg 143a,q, C.A. Garner155, V. Garonne 29, S.J. Gasiorowski 138, P. Gaspar 82b, G. Gaudio 73a, V. Gautam13, P. Gauzzi 75a,75b, I.L. Gavrilenko 37, A. Gavrilyuk 37, C. Gay 164, G. Gaycken 48, E.N. Gazis 10, A.A. Geanta 27b,27e, C.M. Gee 136, J. Geisen 98, C. Gemme 57b, M.H. Genest 60, S. Gentile 75a,75b, S. George 95, W.F. George 20, T. Geralis 46, L.O. Gerlach55, P. Gessinger-Befurt 36, M.E. Geyik 171, M. Ghasemi Bostanabad 165, M. Ghneimat 141, K. Ghorbanian 94, A. Ghosal 141, A. Ghosh 160, A. Ghosh 7, B. Giacobbe 23b, S. Giagu 75a,75b, P. Giannetti 74a, A. Giannini 62a, S.M. Gibson 95, M. Gignac 136, D.T. Gil 85b, A.K. Gilbert 85a, B.J. Gilbert 41, D. Gillberg 34, G. Gilles 114, N.E.K. Gillwald 48, L. Ginabat 127, D.M. Gingrich 2,ah, M.P. Giordani 69a,69c, P.F. Giraud 135, G. Giugliarelli 69a,69c, D. Giugni 71a, F. Giuli 36, I. Gkialas 9,k, L.K. Gladilin 37, C. Glasman 99, G.R. Gledhill 123, M. Glisic123, I. Gnesi 43b,g, Y. Go 29,ak, M. Goblirsch-Kolb 26, B. Gocke 49, D. Godin108, B. Gokturk 21a, S. Goldfarb 105, T. Golling 56, M.G.D. Gololo33g, D. Golubkov 37, J.P. Gombas 107, A. Gomes 130a,130b, G. Gomes Da Silva 141, A.J. Gomez Delegido 163, R. Goncalves Gama 55, R. Gonçalo 130a,130c, G. Gonella 123, L. Gonella 20, A. Gongadze 38, F. Gonnella 20, J.L. Gonski 41, R.Y. González Andana 52, S. González de la Hoz 163, S. Gonzalez Fernandez 13, R. Gonzalez Lopez 92, C. Gonzalez Renteria 17a, R. Gonzalez Suarez 161, S. Gonzalez-Sevilla 56, G.R. Gonzalvo Rodriguez 163, L. Goossens 36, N.A. Gorasia 20, P.A. Gorbounov 37, B. Gorini 36, E. Gorini 70a,70b, A. Gorišek 93, A.T. Goshaw 51, M.I. Gostkin 38, S. Goswami 121, C.A. Gottardo 36, M. Gouighri 35b, V. Goumarre 48, A.G. Goussiou 138, N. Govender 33c, C. Goy 4, I. Grabowska-Bold 85a, K. Graham 34, E. Gramstad 125, S. Grancagnolo 18, M. Grandi 146, V. Gratchev37,∗, P.M. Gravila 27f, F.G. Gravili 70a,70b, H.M. Gray 17a, M. Greco 70a,70b, C. Grefe 24, I.M. Gregor 48, P. Grenier 143a, C. Grieco 13, A.A. Grillo 136, K. Grimm 31,n, S. Grinstein 13,v, J.-F. Grivaz 66, E. Gross 169, J. Grosse-Knetter 55, C. Grud106, J.C. Grundy 126, L. Guan 106, W. Guan 170, C. Gubbels 164, J.G.R. Guerrero Rojas 163, G. Guerrieri 69a,69b, F. Guescini 110, R. Gugel 100, J.A.M. Guhit 106, A. Guida 48, T. Guillemin 4, E. Guilloton 167,134, S. Guindon 36, F. Guo 14a,14d, J. Guo 62c, L. Guo 66, Y. Guo 106, R. Gupta 48, S. Gurbuz 24, S.S. Gurdasani 54, G. Gustavino 36, M. Guth 56, P. Gutierrez 120, L.F. Gutierrez Zagazeta 128, C. Gutschow 96, C. Guyot 135, C. Gwenlan 126, C.B. Gwilliam 92, E.S. Haaland 125, A. Haas 117, M. Habedank 48, C. Haber 17a, H.K. Hadavand 8, A. Hadef 100, S. Hadzic 110, E.H. Haines 96, M. Haleem 166, J. Haley 121, J.J. Hall 139, G.D. Hallewell 102, L. Halser 19, K. Hamano 165, H. Hamdaoui 35e, M. Hamer 24, G.N. Hamity 52, J. Han 62b, K. Han 62a, L. Han 14c, L. Han 62a, S. Han 17a, Y.F. Han 155, K. Hanagaki 83, M. Hance 136, D.A. Hangal 41,ad, H. Hanif 142, M.D. Hank 39, R. Hankache 101, J.B. Hansen 42, J.D. Hansen 42, P.H. Hansen 42, K. Hara 157, D. Harada 56, T. Harenberg 171, S. Harkusha 37, Y.T. Harris 126, N.M. Harrison 119, P.F. Harrison167, N.M. Hartman 143a, N.M. Hartmann 109, Y. Hasegawa 140, A. Hasib 52, S. Haug 19, R. Hauser 107, M. Havranek 132, C.M. Hawkes 20, R.J. Hawkings 36, S. Hayashida 111, D. Hayden 107, – 35 – JHEP07(2023)133 C. Hayes 106, R.L. Hayes 164, C.P. Hays 126, J.M. Hays 94, H.S. Hayward 92, F. He 62a, Y. He 154, Y. He 127, M.P. Heath 52, N.B. Heatley 94, V. Hedberg 98, A.L. Heggelund 125, N.D. Hehir 94, C. Heidegger 54, K.K. Heidegger 54, W.D. Heidorn 81, J. Heilman 34, S. Heim 48, T. Heim 17a, J.G. Heinlein 128, J.J. Heinrich 123, L. Heinrich 110,af , J. Hejbal 131, L. Helary 48, A. Held 170, S. Hellesund 125, C.M. Helling 164, S. Hellman 47a,47b, C. Helsens 36, R.C.W. Henderson91, L. Henkelmann 32, A.M. Henriques Correia36, H. Herde 98, Y. Hernández Jiménez 145, L.M. Herrmann 24, T. Herrmann 50, G. Herten 54, R. Hertenberger 109, L. Hervas 36, N.P. Hessey 156a, H. Hibi 84, E. Higón-Rodriguez 163, S.J. Hillier 20, I. Hinchliffe 17a, F. Hinterkeuser 24, M. Hirose 124, S. Hirose 157, D. Hirschbuehl 171, T.G. Hitchings 101, B. Hiti 93, J. Hobbs 145, R. Hobincu 27e, N. Hod 169, M.C. Hodgkinson 139, B.H. Hodkinson 32, A. Hoecker 36, J. Hofer 48, E.F. Hofgard 143b, D. Hohn 54, T. Holm 24, M. Holzbock 110, L.B.A.H. Hommels 32, B.P. Honan 101, J. Hong 62c, T.M. Hong 129, J.C. Honig 54, B.H. Hooberman 162, W.H. Hopkins 6, Y. Horii 111, S. Hou 148, A.S. Howard 93, J. Howarth 59, J. Hoya 6, M. Hrabovsky 122, A. Hrynevich 48, T. Hryn’ova 4, P.J. Hsu 65, S.-C. Hsu 138, Q. Hu 41, Y.F. Hu 14a,14d,aj, D.P. Huang 96, S. Huang 64b, X. Huang 14c, Y. Huang 62a, Y. Huang 14a, Z. Huang 101, Z. Hubacek 132, M. Huebner 24, F. Huegging 24, T.B. Huffman 126, M. Huhtinen 36, S.K. Huiberts 16, R. Hulsken 104, N. Huseynov 12,a, J. Huston 107, J. Huth 61, R. Hyneman 143a, S. Hyrych 28a, G. Iacobucci 56, G. Iakovidis 29, I. Ibragimov 141, L. Iconomidou-Fayard 66, P. Iengo 72a,72b, R. Iguchi 153, T. Iizawa 56, Y. Ikegami 83, A. Ilg 19, N. Ilic 155, H. Imam 35a, T. Ingebretsen Carlson 47a,47b, G. Introzzi 73a,73b, M. Iodice 77a, V. Ippolito 75a,75b, M. Ishino 153, W. Islam 170, C. Issever 18,48, S. Istin 21a,am, H. Ito 168, J.M. Iturbe Ponce 64a, R. Iuppa 78a,78b, A. Ivina 169, J.M. Izen 45, V. Izzo 72a, P. Jacka 131,132, P. Jackson 1, R.M. Jacobs 48, B.P. Jaeger 142, C.S. Jagfeld 109, P. Jain 54, G. Jäkel 171, K. Jakobs 54, T. Jakoubek 169, J. Jamieson 59, K.W. Janas 85a, G. Jarlskog 98, A.E. Jaspan 92, M. Javurkova 103, F. Jeanneau 135, L. Jeanty 123, J. Jejelava 149a,ab, P. Jenni 54,h, C.E. Jessiman 34, S. Jézéquel 4, C. Jia62b, J. Jia 145, X. Jia 61, X. Jia 14a,14d, Z. Jia 14c, Y. Jiang62a, S. Jiggins 52, J. Jimenez Pena 110, S. Jin 14c, A. Jinaru 27b, O. Jinnouchi 154, P. Johansson 139, K.A. Johns 7, J.W. Johnson 136, D.M. Jones 32, E. Jones 167, P. Jones 32, R.W.L. Jones 91, T.J. Jones 92, R. Joshi 119, J. Jovicevic 15, X. Ju 17a, J.J. Junggeburth 36, T. Junkermann 63a, A. Juste Rozas 13,v, S. Kabana 137e, A. Kaczmarska 86, M. Kado 75a,75b, H. Kagan 119, M. Kagan 143a, A. Kahn41, A. Kahn 128, C. Kahra 100, T. Kaji 168, E. Kajomovitz 150, N. Kakati 169, C.W. Kalderon 29, A. Kamenshchikov 155, S. Kanayama 154, N.J. Kang 136, D. Kar 33g, K. Karava 126, M.J. Kareem 156b, E. Karentzos 54, I. Karkanias 152,f , S.N. Karpov 38, Z.M. Karpova 38, V. Kartvelishvili 91, A.N. Karyukhin 37, E. Kasimi 152,f , C. Kato 62d, J. Katzy 48, S. Kaur 34, K. Kawade 140, K. Kawagoe 89, T. Kawamoto 135, G. Kawamura55, E.F. Kay 165, F.I. Kaya 158, S. Kazakos 13, V.F. Kazanin 37, Y. Ke 145, J.M. Keaveney 33a, R. Keeler 165, G.V. Kehris 61, J.S. Keller 34, A.S. Kelly96, D. Kelsey 146, J.J. Kempster 146, K.E. Kennedy 41, P.D. Kennedy 100, O. Kepka 131, B.P. Kerridge 167, S. Kersten 171, B.P. Kerševan 93, S. Keshri 66, L. Keszeghova 28a, S. Ketabchi Haghighat 155, – 36 – JHEP07(2023)133 M. Khandoga 127, A. Khanov 121, A.G. Kharlamov 37, T. Kharlamova 37, E.E. Khoda 138, T.J. Khoo 18, G. Khoriauli 166, J. Khubua 149b, Y.A.R. Khwaira 66, M. Kiehn 36, A. Kilgallon 123, D.W. Kim 47a,47b, E. Kim 154, Y.K. Kim 39, N. Kimura 96, A. Kirchhoff 55, D. Kirchmeier 50, C. Kirfel 24, J. Kirk 134, A.E. Kiryunin 110, T. Kishimoto 153, D.P. Kisliuk155, C. Kitsaki 10, O. Kivernyk 24, M. Klassen 63a, C. Klein 34, L. Klein 166, M.H. Klein 106, M. Klein 92, S.B. Klein 56, U. Klein 92, P. Klimek 36, A. Klimentov 29, F. Klimpel 110, T. Klioutchnikova 36, P. Kluit 114, S. Kluth 110, E. Kneringer 79, T.M. Knight 155, A. Knue 54, D. Kobayashi89, R. Kobayashi 87, M. Kocian 143a, P. Kodyš 133, D.M. Koeck 146, P.T. Koenig 24, T. Koffas 34, M. Kolb 135, I. Koletsou 4, T. Komarek 122, K. Köneke 54, A.X.Y. Kong 1, T. Kono 118, N. Konstantinidis 96, B. Konya 98, R. Kopeliansky 68, S. Koperny 85a, K. Korcyl 86, K. Kordas 152,f , G. Koren 151, A. Korn 96, S. Korn 55, I. Korolkov 13, N. Korotkova 37, B. Kortman 114, O. Kortner 110, S. Kortner 110, W.H. Kostecka 115, V.V. Kostyukhin 141, A. Kotsokechagia 135, A. Kotwal 51, A. Koulouris 36, A. Kourkoumeli-Charalampidi 73a,73b, C. Kourkoumelis 9, E. Kourlitis 6, O. Kovanda 146, R. Kowalewski 165, W. Kozanecki 135, A.S. Kozhin 37, V.A. Kramarenko 37, G. Kramberger 93, P. Kramer 100, M.W. Krasny 127, A. Krasznahorkay 36, J.A. Kremer 100, T. Kresse 50, J. Kretzschmar 92, K. Kreul 18, P. Krieger 155, S. Krishnamurthy 103, M. Krivos 133, K. Krizka 17a, K. Kroeninger 49, H. Kroha 110, J. Kroll 131, J. Kroll 128, K.S. Krowpman 107, U. Kruchonak 38, H. Krüger 24, N. Krumnack81, M.C. Kruse 51, J.A. Krzysiak 86, O. Kuchinskaia 37, S. Kuday 3a, D. Kuechler 48, J.T. Kuechler 48, S. Kuehn 36, R. Kuesters 54, T. Kuhl 48, V. Kukhtin 38, Y. Kulchitsky 37,a, S. Kuleshov 137d,137b, M. Kumar 33g, N. Kumari 102, A. Kupco 131, T. Kupfer49, A. Kupich 37, O. Kuprash 54, H. Kurashige 84, L.L. Kurchaninov 156a, Y.A. Kurochkin 37, A. Kurova 37, M. Kuze 154, A.K. Kvam 103, J. Kvita 122, T. Kwan 104, K.W. Kwok 64a, N.G. Kyriacou 106, L.A.O. Laatu 102, C. Lacasta 163, F. Lacava 75a,75b, H. Lacker 18, D. Lacour 127, N.N. Lad 96, E. Ladygin 38, B. Laforge 127, T. Lagouri 137e, S. Lai 55, I.K. Lakomiec 85a, N. Lalloue 60, J.E. Lambert 120, S. Lammers 68, W. Lampl 7, C. Lampoudis 152,f , A.N. Lancaster 115, E. Lançon 29, U. Landgraf 54, M.P.J. Landon 94, V.S. Lang 54, R.J. Langenberg 103, A.J. Lankford 160, F. Lanni 36, K. Lantzsch 24, A. Lanza 73a, A. Lapertosa 57b,57a, J.F. Laporte 135, T. Lari 71a, F. Lasagni Manghi 23b, M. Lassnig 36, V. Latonova 131, A. Laudrain 100, A. Laurier 150, S.D. Lawlor 95, Z. Lawrence 101, M. Lazzaroni 71a,71b, B. Le101, B. Leban 93, A. Lebedev 81, M. LeBlanc 36, T. LeCompte 6, F. Ledroit-Guillon 60, A.C.A. Lee96, G.R. Lee 16, S.C. Lee 148, S. Lee 47a,47b, T.F. Lee 92, L.L. Leeuw 33c, H.P. Lefebvre 95, M. Lefebvre 165, C. Leggett 17a, K. Lehmann 142, G. Lehmann Miotto 36, M. Leigh 56, W.A. Leight 103, A. Leisos 152,u, M.A.L. Leite 82c, C.E. Leitgeb 48, R. Leitner 133, K.J.C. Leney 44, T. Lenz 24, S. Leone 74a, C. Leonidopoulos 52, A. Leopold 144, C. Leroy 108, R. Les 107, C.G. Lester 32, M. Levchenko 37, J. Levêque 4, D. Levin 106, L.J. Levinson 169, M.P. Lewicki 86, D.J. Lewis 4, A. Li 5, B. Li 62b, C. Li62a, C-Q. Li 62c, H. Li 62a, H. Li 62b, H. Li 14c, H. Li 62b, J. Li 62c, K. Li 138, L. Li 62c, M. Li 14a,14d, Q.Y. Li 62a, S. Li 14a,14d, S. Li 62d,62c,e, T. Li 62b, X. Li 104, Z. Li 62b, Z. Li 126, Z. Li 104, Z. Li 92, Z. Li 14a,14d, Z. Liang 14a, M. Liberatore 48, B. Liberti 76a, – 37 – JHEP07(2023)133 K. Lie 64c, J. Lieber Marin 82b, H. Lien 68, K. Lin 107, R.A. Linck 68, R.E. Lindley 7, J.H. Lindon 2, A. Linss 48, E. Lipeles 128, A. Lipniacka 16, A. Lister 164, J.D. Little 4, B. Liu 14a, B.X. Liu 142, D. Liu 62d,62c, J.B. Liu 62a, J.K.K. Liu 32, K. Liu 62d,62c, M. Liu 62a, M.Y. Liu 62a, P. Liu 14a, Q. Liu 62d,138,62c, X. Liu 62a, Y. Liu 14c,14d, Y.L. Liu 106, Y.W. Liu 62a, M. Livan 73a,73b, J. Llorente Merino 142, S.L. Lloyd 94, E.M. Lobodzinska 48, P. Loch 7, S. Loffredo 76a,76b, T. Lohse 18, K. Lohwasser 139, E. Loiacono 48, M. Lokajicek 131, J.D. Long 162, I. Longarini 160, L. Longo 70a,70b, R. Longo 162, I. Lopez Paz 67, A. Lopez Solis 48, J. Lorenz 109, N. Lorenzo Martinez 4, A.M. Lory 109, X. Lou 47a,47b, X. Lou 14a,14d, A. Lounis 66, J. Love 6, P.A. Love 91, J.J. Lozano Bahilo 163, G. Lu 14a,14d, M. Lu 80, S. Lu 128, Y.J. Lu 65, H.J. Lubatti 138, C. Luci 75a,75b, F.L. Lucio Alves 14c, A. Lucotte 60, F. Luehring 68, I. Luise 145, O. Lukianchuk 66, O. Lundberg 144, B. Lund-Jensen 144, N.A. Luongo 123, M.S. Lutz 151, D. Lynn 29, H. Lyons92, R. Lysak 131, E. Lytken 98, F. Lyu 14a, V. Lyubushkin 38, T. Lyubushkina 38, M.M. Lyukova 145, H. Ma 29, L.L. Ma 62b, Y. Ma 96, D.M. Mac Donell 165, G. Maccarrone 53, J.C. MacDonald 139, R. Madar 40, W.F. Mader 50, J. Maeda 84, T. Maeno 29, M. Maerker 50, H. Maguire 139, A. Maio 130a,130b,130d, K. Maj 85a, O. Majersky 48, S. Majewski 123, N. Makovec 66, V. Maksimovic 15, B. Malaescu 127, Pa. Malecki 86, V.P. Maleev 37, F. Malek 60, D. Malito 43b,43a, U. Mallik 80, C. Malone 32, S. Maltezos10, S. Malyukov38, J. Mamuzic 13, G. Mancini 53, G. Manco 73a,73b, J.P. Mandalia 94, I. Mandić 93, L. Manhaes de Andrade Filho 82a, I.M. Maniatis 169, J. Manjarres Ramos 50, D.C. Mankad 169, A. Mann 109, B. Mansoulie 135, S. Manzoni 36, A. Marantis 152,u, G. Marchiori 5, M. Marcisovsky 131, C. Marcon 71a,71b, M. Marinescu 20, M. Marjanovic 120, E.J. Marshall 91, Z. Marshall 17a, S. Marti-Garcia 163, T.A. Martin 167, V.J. Martin 52, B. Martin dit Latour 16, L. Martinelli 75a,75b, M. Martinez 13,v, P. Martinez Agullo 163, V.I. Martinez Outschoorn 103, P. Martinez Suarez 13, S. Martin-Haugh 134, V.S. Martoiu 27b, A.C. Martyniuk 96, A. Marzin 36, S.R. Maschek 110, D. Mascione 78a,78b, L. Masetti 100, T. Mashimo 153, J. Masik 101, A.L. Maslennikov 37, L. Massa 23b, P. Massarotti 72a,72b, P. Mastrandrea 74a,74b, A. Mastroberardino 43b,43a, T. Masubuchi 153, T. Mathisen 161, N. Matsuzawa153, J. Maurer 27b, B. Maček 93, D.A. Maximov 37, R. Mazini 148, I. Maznas 152,f , M. Mazza 107, S.M. Mazza 136, C. Mc Ginn 29,ak, J.P. Mc Gowan 104, S.P. Mc Kee 106, E.F. McDonald 105, A.E. McDougall 114, J.A. Mcfayden 146, G. Mchedlidze 149b, R.P. Mckenzie 33g, T.C. Mclachlan 48, D.J. Mclaughlin 96, K.D. McLean 165, S.J. McMahon 134, P.C. McNamara 105, C.M. Mcpartland 92, R.A. McPherson 165,y, T. Megy 40, S. Mehlhase 109, A. Mehta 92, B. Meirose 45, D. Melini 150, B.R. Mellado Garcia 33g, A.H. Melo 55, F. Meloni 48, E.D. Mendes Gouveia 130a, A.M. Mendes Jacques Da Costa 20, H.Y. Meng 155, L. Meng 91, S. Menke 110, M. Mentink 36, E. Meoni 43b,43a, C. Merlassino 126, L. Merola 72a,72b, C. Meroni 71a, G. Merz106, O. Meshkov 37, J. Metcalfe 6, A.S. Mete 6, C. Meyer 68, J-P. Meyer 135, M. Michetti 18, R.P. Middleton 134, L. Mijović 52, G. Mikenberg 169, M. Mikestikova 131, M. Mikuž 93, H. Mildner 139, A. Milic 36, C.D. Milke 44, D.W. Miller 39, L.S. Miller 34, A. Milov 169, D.A. Milstead47a,47b, T. Min14c, A.A. Minaenko 37, I.A. Minashvili 149b, – 38 – JHEP07(2023)133 L. Mince 59, A.I. Mincer 117, B. Mindur 85a, M. Mineev 38, Y. Mino 87, L.M. Mir 13, M. Miralles Lopez 163, M. Mironova 126, M.C. Missio 113, T. Mitani 168, A. Mitra 167, V.A. Mitsou 163, A. Mitta 71b, O. Miu 155, P.S. Miyagawa 94, Y. Miyazaki89, A. Mizukami 83, J.U. Mjörnmark 98, T. Mkrtchyan 63a, M. Mlinarevic 96, T. Mlinarevic 96, M. Mlynarikova 36, T. Moa 47a,47b, S. Mobius 55, K. Mochizuki 108, P. Moder 48, P. Mogg 109, A.F. Mohammed 14a,14d, S. Mohapatra 41, G. Mokgatitswane 33g, B. Mondal 141, S. Mondal 132, K. Mönig 48, E. Monnier 102, L. Monsonis Romero163, J. Montejo Berlingen 83, M. Montella 119, F. Monticelli 90, N. Morange 66, A.L. Moreira De Carvalho 130a, M. Moreno Llácer 163, C. Moreno Martinez 56, P. Morettini 57b, S. Morgenstern 167, M. Morii 61, M. Morinaga 153, A.K. Morley 36, F. Morodei 75a,75b, L. Morvaj 36, P. Moschovakos 36, B. Moser 36, M. Mosidze149b, T. Moskalets 54, P. Moskvitina 113, J. Moss 31,o, E.J.W. Moyse 103, O. Mtintsilana 33g, S. Muanza 102, J. Mueller 129, D. Muenstermann 91, R. Müller 19, G.A. Mullier 161, J.J. Mullin128, D.P. Mungo 155, J.L. Munoz Martinez 13, D. Munoz Perez 163, F.J. Munoz Sanchez 101, M. Murin 101, W.J. Murray 167,134, A. Murrone 71a,71b, J.M. Muse 120, M. Muškinja 17a, C. Mwewa 29, A.G. Myagkov 37,a, A.J. Myers 8, A.A. Myers129, G. Myers 68, M. Myska 132, B.P. Nachman 17a, O. Nackenhorst 49, A. Nag 50, K. Nagai 126, K. Nagano 83, J.L. Nagle 29,ak, E. Nagy 102, A.M. Nairz 36, Y. Nakahama 83, K. Nakamura 83, H. Nanjo 124, R. Narayan 44, E.A. Narayanan 112, I. Naryshkin 37, M. Naseri 34, C. Nass 24, G. Navarro 22a, J. Navarro-Gonzalez 163, R. Nayak 151, A. Nayaz 18, P.Y. Nechaeva 37, F. Nechansky 48, L. Nedic 126, T.J. Neep 20, A. Negri 73a,73b, M. Negrini 23b, C. Nellist 113, C. Nelson 104, K. Nelson 106, S. Nemecek 131, M. Nessi 36,i, M.S. Neubauer 162, F. Neuhaus 100, J. Neundorf 48, R. Newhouse 164, P.R. Newman 20, C.W. Ng 129, Y.S. Ng18, Y.W.Y. Ng 48, B. Ngair 35e, H.D.N. Nguyen 108, R.B. Nickerson 126, R. Nicolaidou 135, J. Nielsen 136, M. Niemeyer 55, N. Nikiforou 36, V. Nikolaenko 37,a, I. Nikolic-Audit 127, K. Nikolopoulos 20, P. Nilsson 29, I. Ninca 48, H.R. Nindhito 56, G. Ninio 151, A. Nisati 75a, N. Nishu 2, R. Nisius 110, J-E. Nitschke 50, E.K. Nkadimeng 33g, S.J. Noacco Rosende 90, T. Nobe 153, D.L. Noel 32, Y. Noguchi 87, T. Nommensen 147, M.A. Nomura29, M.B. Norfolk 139, R.R.B. Norisam 96, B.J. Norman 34, J. Novak 93, T. Novak 48, O. Novgorodova 50, L. Novotny 132, R. Novotny 112, L. Nozka 122, K. Ntekas 160, N.M.J. Nunes De Moura Junior 82b, E. Nurse96, J. Ocariz 127, A. Ochi 84, I. Ochoa 130a, S. Oerdek 161, J.T. Offermann 39, A. Ogrodnik 85a, A. Oh 101, C.C. Ohm 144, H. Oide 83, R. Oishi 153, M.L. Ojeda 48, Y. Okazaki 87, M.W. O’Keefe92, Y. Okumura 153, A. Olariu27b, L.F. Oleiro Seabra 130a, S.A. Olivares Pino 137e, D. Oliveira Damazio 29, D. Oliveira Goncalves 82a, J.L. Oliver 160, M.J.R. Olsson 160, A. Olszewski 86, J. Olszowska 86,∗, Ö.O. Öncel 54, D.C. O’Neil 142, A.P. O’Neill 19, A. Onofre 130a,130e, P.U.E. Onyisi 11, M.J. Oreglia 39, G.E. Orellana 90, D. Orestano 77a,77b, N. Orlando 13, R.S. Orr 155, V. O’Shea 59, R. Ospanov 62a, G. Otero y Garzon 30, H. Otono 89, P.S. Ott 63a, G.J. Ottino 17a, M. Ouchrif 35d, J. Ouellette 29,ak, F. Ould-Saada 125, M. Owen 59, R.E. Owen 134, K.Y. Oyulmaz 21a, V.E. Ozcan 21a, N. Ozturk 8, S. Ozturk 21d, J. Pacalt 122, H.A. Pacey 32, K. Pachal 51, A. Pacheco Pages 13, C. Padilla Aranda 13, G. Padovano 75a,75b, S. Pagan Griso 17a, G. Palacino 68, A. Palazzo 70a,70b, S. Palestini 36, J. Pan 172, T. Pan 64a, D.K. Panchal 11, – 39 – JHEP07(2023)133 C.E. Pandini 114, J.G. Panduro Vazquez 95, H. Pang 14b, P. Pani 48, G. Panizzo 69a,69c, L. Paolozzi 56, C. Papadatos 108, S. Parajuli 44, A. Paramonov 6, C. Paraskevopoulos 10, D. Paredes Hernandez 64b, T.H. Park 155, M.A. Parker 32, F. Parodi 57b,57a, E.W. Parrish 115, V.A. Parrish 52, J.A. Parsons 41, U. Parzefall 54, B. Pascual Dias 108, L. Pascual Dominguez 151, V.R. Pascuzzi 17a, F. Pasquali 114, E. Pasqualucci 75a, S. Passaggio 57b, F. Pastore 95, P. Pasuwan 47a,47b, P. Patel 86, U.M. Patel 51, J.R. Pater 101, T. Pauly 36, J. Pearkes 143a, M. Pedersen 125, R. Pedro 130a, S.V. Peleganchuk 37, O. Penc 36, E.A. Pender52, C. Peng 64b, H. Peng 62a, K.E. Penski 109, M. Penzin 37, B.S. Peralva 82d, A.P. Pereira Peixoto 60, L. Pereira Sanchez 47a,47b, D.V. Perepelitsa 29,ak, E. Perez Codina 156a, M. Perganti 10, L. Perini 71a,71b,∗, H. Pernegger 36, S. Perrella 36, A. Perrevoort 113, O. Perrin 40, K. Peters 48, R.F.Y. Peters 101, B.A. Petersen 36, T.C. Petersen 42, E. Petit 102, V. Petousis 132, C. Petridou 152,f , A. Petrukhin 141, M. Pettee 17a, N.E. Pettersson 36, A. Petukhov 37, K. Petukhova 133, A. Peyaud 135, R. Pezoa 137f, L. Pezzotti 36, G. Pezzullo 172, T.M. Pham 170, T. Pham 105, P.W. Phillips 134, M.W. Phipps 162, G. Piacquadio 145, E. Pianori 17a, F. Piazza 71a,71b, R. Piegaia 30, D. Pietreanu 27b, A.D. Pilkington 101, M. Pinamonti 69a,69c, J.L. Pinfold 2, B.C. Pinheiro Pereira 130a, C. Pitman Donaldson96, D.A. Pizzi 34, L. Pizzimento 76a,76b, A. Pizzini 114, M.-A. Pleier 29, V. Plesanovs54, V. Pleskot 133, E. Plotnikova38, G. Poddar 4, R. Poettgen 98, L. Poggioli 127, I. Pogrebnyak 107, D. Pohl 24, I. Pokharel 55, S. Polacek 133, G. Polesello 73a, A. Poley 142,156a, R. Polifka 132, A. Polini 23b, C.S. Pollard 167, Z.B. Pollock 119, V. Polychronakos 29, E. Pompa Pacchi 75a,75b, D. Ponomarenko 113, L. Pontecorvo 36, S. Popa 27a, G.A. Popeneciu 27d, D.M. Portillo Quintero 156a, S. Pospisil 132, P. Postolache 27c, K. Potamianos 126, P.P. Potepa 85a, I.N. Potrap 38, C.J. Potter 32, H. Potti 1, T. Poulsen 48, J. Poveda 163, M.E. Pozo Astigarraga 36, A. Prades Ibanez 163, M.M. Prapa 46, J. Pretel 54, D. Price 101, M. Primavera 70a, M.A. Principe Martin 99, R. Privara 122, M.L. Proffitt 138, N. Proklova 128, K. Prokofiev 64c, G. Proto 76a,76b, S. Protopopescu 29, J. Proudfoot 6, M. Przybycien 85a, J.E. Puddefoot 139, D. Pudzha 37, D. Pullia 71b, P. Puzo66, D. Pyatiizbyantseva 37, J. Qian 106, D. Qichen 101, Y. Qin 101, T. Qiu 94, A. Quadt 55, M. Queitsch-Maitland 101, G. Quetant 56, G. Rabanal Bolanos 61, D. Rafanoharana 54, F. Ragusa 71a,71b, J.L. Rainbolt 39, J.A. Raine 56, S. Rajagopalan 29, E. Ramakoti 37, K. Ran 48,14d, N.P. Rapheeha 33g, V. Raskina 127, D.F. Rassloff 63a, S. Rave 100, B. Ravina 55, I. Ravinovich 169, M. Raymond 36, A.L. Read 125, N.P. Readioff 139, D.M. Rebuzzi 73a,73b, G. Redlinger 29, K. Reeves 45, J.A. Reidelsturz 171, D. Reikher 151, A. Rej 141, C. Rembser 36, A. Renardi 48, M. Renda 27b, M.B. Rendel110, F. Renner 48, A.G. Rennie 59, S. Resconi 71a, M. Ressegotti 57b,57a, E.D. Resseguie 17a, S. Rettie 36, J.G. Reyes Rivera 107, B. Reynolds119, E. Reynolds 17a, M. Rezaei Estabragh 171, O.L. Rezanova 37, P. Reznicek 133, N. Ribaric 91, E. Ricci 78a,78b, R. Richter 110, S. Richter 47a,47b, E. Richter-Was 85b, M. Ridel 127, S. Ridouani 35d, P. Rieck 117, P. Riedler 36, M. Rijssenbeek 145, A. Rimoldi 73a,73b, M. Rimoldi 48, L. Rinaldi 23b,23a, T.T. Rinn 29, M.P. Rinnagel 109, G. Ripellino 161, I. Riu 13, P. Rivadeneira 48, J.C. Rivera Vergara 165, F. Rizatdinova 121, E. Rizvi 94, C. Rizzi 56, B.A. Roberts 167, B.R. Roberts 17a, S.H. Robertson 104,y, M. Robin 48, D. Robinson 32, – 40 – JHEP07(2023)133 78 (a)INFN-TIFPA; (b)Università degli Studi di Trento, Trento; Italy 79 Universität Innsbruck, Department of Astro and Particle Physics, Innsbruck; Austria 80 University of Iowa, Iowa City IA; United States of America 81 Department of Physics and Astronomy, Iowa State University, Ames IA; United States of America 82 (a)Departamento de Engenharia Elétrica, Universidade Federal de Juiz de Fora (UFJF), Juiz de Fora; (b)Universidade Federal do Rio De Janeiro COPPE/EE/IF, Rio de Janeiro; (c)Instituto de Física, Universidade de São Paulo, São Paulo; (d)Rio de Janeiro State University, Rio de Janeiro; Brazil 83 KEK, High Energy Accelerator Research Organization, Tsukuba; Japan 84 Graduate School of Science, Kobe University, Kobe; Japan 85 (a)AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, Krakow; (b)Marian Smoluchowski Institute of Physics, Jagiellonian University, Krakow; Poland 86 Institute of Nuclear Physics Polish Academy of Sciences, Krakow; Poland 87 Faculty of Science, Kyoto University, Kyoto; Japan 88 Kyoto University of Education, Kyoto; Japan 89 Research Center for Advanced Particle Physics and Department of Physics, Kyushu University, Fukuoka ; Japan 90 Instituto de Física La Plata, Universidad Nacional de La Plata and CONICET, La Plata; Argentina 91 Physics Department, Lancaster University, Lancaster; United Kingdom 92 Oliver Lodge Laboratory, University of Liverpool, Liverpool; United Kingdom 93 Department of Experimental Particle Physics, Jožef Stefan Institute and Department of Physics, University of Ljubljana, Ljubljana; Slovenia 94 School of Physics and Astronomy, Queen Mary University of London, London; United Kingdom 95 Department of Physics, Royal Holloway University of London, Egham; United Kingdom 96 Department of Physics and Astronomy, University College London, London; United Kingdom 97 Louisiana Tech University, Ruston LA; United States of America 98 Fysiska institutionen, Lunds universitet, Lund; Sweden 99 Departamento de Física Teorica C-15 and CIAFF, Universidad Autónoma de Madrid, Madrid; Spain 100 Institut für Physik, Universität Mainz, Mainz; Germany 101 School of Physics and Astronomy, University of Manchester, Manchester; United Kingdom 102 CPPM, Aix-Marseille Université, CNRS/IN2P3, Marseille; France 103 Department of Physics, University of Massachusetts, Amherst MA; United States of America 104 Department of Physics, McGill University, Montreal QC; Canada 105 School of Physics, University of Melbourne, Victoria; Australia 106 Department of Physics, University of Michigan, Ann Arbor MI; United States of America 107 Department of Physics and Astronomy, Michigan State University, East Lansing MI; United States of America 108 Group of Particle Physics, University of Montreal, Montreal QC; Canada 109 Fakultät für Physik, Ludwig-Maximilians-Universität München, München; Germany 110 Max-Planck-Institut für Physik (Werner-Heisenberg-Institut), München; Germany 111 Graduate School of Science and Kobayashi-Maskawa Institute, Nagoya University, Nagoya; Japan 112 Department of Physics and Astronomy, University of New Mexico, Albuquerque NM; United States of America 113 Institute for Mathematics, Astrophysics and Particle Physics, Radboud University/Nikhef, Nijmegen; Netherlands 114 Nikhef National Institute for Subatomic Physics and University of Amsterdam, Amsterdam; Netherlands 115 Department of Physics, Northern Illinois University, DeKalb IL; United States of America 116 (a)New York University Abu Dhabi, Abu Dhabi; (b)University of Sharjah, Sharjah; United Arab Emirates 117 Department of Physics, New York University, New York NY; United States of America 118 Ochanomizu University, Otsuka, Bunkyo-ku, Tokyo; Japan 119 Ohio State University, Columbus OH; United States of America 120 Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, Norman OK; United States of America – 47 – JHEP07(2023)133 121 Department of Physics, Oklahoma State University, Stillwater OK; United States of America 122 Palacký University, Joint Laboratory of Optics, Olomouc; Czech Republic 123 Institute for Fundamental Science, University of Oregon, Eugene, OR; United States of America 124 Graduate School of Science, Osaka University, Osaka; Japan 125 Department of Physics, University of Oslo, Oslo; Norway 126 Department of Physics, Oxford University, Oxford; United Kingdom 127 LPNHE, Sorbonne Université, Université Paris Cité, CNRS/IN2P3, Paris; France 128 Department of Physics, University of Pennsylvania, Philadelphia PA; United States of America 129 Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh PA; United States of America 130 (a)Laboratório de Instrumentação e Física Experimental de Partículas - LIP, Lisboa; (b)Departamento de Física, Faculdade de Ciências, Universidade de Lisboa, Lisboa; (c)Departamento de Física, Universidade de Coimbra, Coimbra; (d)Centro de Física Nuclear da Universidade de Lisboa, Lisboa; (e)Departamento de Física, Universidade do Minho, Braga; (f)Departamento de Física Teórica y del Cosmos, Universidad de Granada, Granada (Spain); (g)Departamento de Física, Instituto Superior Técnico, Universidade de Lisboa, Lisboa; Portugal 131 Institute of Physics of the Czech Academy of Sciences, Prague; Czech Republic 132 Czech Technical University in Prague, Prague; Czech Republic 133 Charles University, Faculty of Mathematics and Physics, Prague; Czech Republic 134 Particle Physics Department, Rutherford Appleton Laboratory, Didcot; United Kingdom 135 IRFU, CEA, Université Paris-Saclay, Gif-sur-Yvette; France 136 Santa Cruz Institute for Particle Physics, University of California Santa Cruz, Santa Cruz CA; United States of America 137 (a)Departamento de Física, Pontificia Universidad Católica de Chile, Santiago; (b)Millennium Institute for Subatomic physics at high energy frontier (SAPHIR), Santiago; (c)Instituto de Investigación Multidisciplinario en Ciencia y Tecnología, y Departamento de Física, Universidad de La Serena; (d)Universidad Andres Bello, Department of Physics, Santiago; (e)Instituto de Alta Investigación, Universidad de Tarapacá, Arica; (f)Departamento de Física, Universidad Técnica Federico Santa María, Valparaíso; Chile 138 Department of Physics, University of Washington, Seattle WA; United States of America 139 Department of Physics and Astronomy, University of Sheffield, Sheffield; United Kingdom 140 Department of Physics, Shinshu University, Nagano; Japan 141 Department Physik, Universität Siegen, Siegen; Germany 142 Department of Physics, Simon Fraser University, Burnaby BC; Canada 143 (a)SLAC National Accelerator Laboratory, Stanford CA; (b)Department of Physics, Stanford University, Stanford CA; United States of America 144 Department of Physics, Royal Institute of Technology, Stockholm; Sweden 145 Departments of Physics and Astronomy, Stony Brook University, Stony Brook NY; United States of America 146 Department of Physics and Astronomy, University of Sussex, Brighton; United Kingdom 147 School of Physics, University of Sydney, Sydney; Australia 148 Institute of Physics, Academia Sinica, Taipei; Taiwan 149 (a)E. Andronikashvili Institute of Physics, Iv. Javakhishvili Tbilisi State University, Tbilisi; (b)High Energy Physics Institute, Tbilisi State University, Tbilisi; (c)University of Georgia, Tbilisi; Georgia 150 Department of Physics, Technion, Israel Institute of Technology, Haifa; Israel 151 Raymond and Beverly Sackler School of Physics and Astronomy, Tel Aviv University, Tel Aviv; Israel 152 Department of Physics, Aristotle University of Thessaloniki, Thessaloniki; Greece 153 International Center for Elementary Particle Physics and Department of Physics, University of Tokyo, Tokyo; Japan 154 Department of Physics, Tokyo Institute of Technology, Tokyo; Japan 155 Department of Physics, University of Toronto, Toronto ON; Canada 156 (a)TRIUMF, Vancouver BC; (b)Department of Physics and Astronomy, York University, Toronto ON; Canada – 48 – JHEP07(2023)133 157 Division of Physics and Tomonaga Center for the History of the Universe, Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba; Japan 158 Department of Physics and Astronomy, Tufts University, Medford MA; United States of America 159 United Arab Emirates University, Al Ain; United Arab Emirates 160 Department of Physics and Astronomy, University of California Irvine, Irvine CA; United States of America 161 Department of Physics and Astronomy, University of Uppsala, Uppsala; Sweden 162 Department of Physics, University of Illinois, Urbana IL; United States of America 163 Instituto de Física Corpuscular (IFIC), Centro Mixto Universidad de Valencia - CSIC, Valencia; Spain 164 Department of Physics, University of British Columbia, Vancouver BC; Canada 165 Department of Physics and Astronomy, University of Victoria, Victoria BC; Canada 166 Fakultät für Physik und Astronomie, Julius-Maximilians-Universität Würzburg, Würzburg; Germany 167 Department of Physics, University of Warwick, Coventry; United Kingdom 168 Waseda University, Tokyo; Japan 169 Department of Particle Physics and Astrophysics, Weizmann Institute of Science, Rehovot; Israel 170 Department of Physics, University of Wisconsin, Madison WI; United States of America 171 Fakultät für Mathematik und Naturwissenschaften, Fachgruppe Physik, Bergische Universität Wuppertal, Wuppertal; Germany 172 Department of Physics, Yale University, New Haven CT; United States of America aAlso Affiliated with an institute covered by a cooperation agreement with CERN bAlso at An-Najah National University, Nablus; Palestine cAlso at Borough of Manhattan Community College, City University of New York, New York NY; United States of America dAlso at Bruno Kessler Foundation, Trento; Italy eAlso at Center for High Energy Physics, Peking University; China fAlso at Center for Interdisciplinary Research and Innovation (CIRI-AUTH), Thessaloniki ; Greece gAlso at Centro Studi e Ricerche Enrico Fermi; Italy hAlso at CERN, Geneva; Switzerland iAlso at Département de Physique Nucléaire et Corpusculaire, Université de Genève, Genève; Switzerland jAlso at Departament de Fisica de la Universitat Autonoma de Barcelona, Barcelona; Spain kAlso at Department of Financial and Management Engineering, University of the Aegean, Chios; Greece lAlso at Department of Physics and Astronomy, Michigan State University, East Lansing MI; United States of America mAlso at Department of Physics, Ben Gurion University of the Negev, Beer Sheva; Israel nAlso at Department of Physics, California State University, East Bay; United States of America oAlso at Department of Physics, California State University, Sacramento; United States of America pAlso at Department of Physics, King’s College London, London; United Kingdom qAlso at Department of Physics, Stanford University, Stanford CA; United States of America rAlso at Department of Physics, University of Fribourg, Fribourg; Switzerland sAlso at Department of Physics, University of Thessaly; Greece tAlso at Department of Physics, Westmont College, Santa Barbara; United States of America uAlso at Hellenic Open University, Patras; Greece vAlso at Institucio Catalana de Recerca i Estudis Avancats, ICREA, Barcelona; Spain wAlso at Institut für Experimentalphysik, Universität Hamburg, Hamburg; Germany xAlso at Institute of Applied Physics, Mohammed VI Polytechnic University, Ben Guerir; Morocco yAlso at Institute of Particle Physics (IPP); Canada zAlso at Institute of Physics and Technology, Ulaanbaatar; Mongolia aa Also at Institute of Physics, Azerbaijan Academy of Sciences, Baku; Azerbaijan ab Also at Institute of Theoretical Physics, Ilia State University, Tbilisi; Georgia – 49 – JHEP07(2023)133 ac Also at L2IT, Université de Toulouse, CNRS/IN2P3, UPS, Toulouse; France ad Also at Lawrence Livermore National Laboratory, Livermore; United States of America ae Also at National Institute of Physics, University of the Philippines Diliman (Philippines); Philippines af Also at Technical University of Munich, Munich; Germany ag Also at The Collaborative Innovation Center of Quantum Matter (CICQM), Beijing; China ah Also at TRIUMF, Vancouver BC; Canada ai Also at Università di Napoli Parthenope, Napoli; Italy aj Also at University of Chinese Academy of Sciences (UCAS), Beijing; China ak Also at University of Colorado Boulder, Department of Physics, Colorado; United States of America al Also at Washington College, Maryland; United States of America am Also at Yeditepe University, Physics Department, Istanbul; Türkiye an Also at Institute for Nuclear Research and Nuclear Energy (INRNE) of the Bulgarian Academy of Sciences, Sofia; Bulgaria ∗Deceased – 50 –