Low-energy windows into the electromagnetic properties of neutrinos

Low-energy windows into the electromagnetic properties of neutrinos Nicola Cargioli nicola.cargi[email protected]n.it INFN– Sezione di Cagliari https://levs-fit.ca.infn.it/ Nicola Cargioli – INFN Cagliari Low-energy windows into the electromagnetic properties of neutrinos Neutrino interactions at low energy pHg !! !! !"! !" "! ""Hg #! ~1GeV τ~0.03'()τ~2.2'() Reactor Neutrinos Decay-at-rest Neutrinos High Flux Only !"! E"~1 − 10 MeV Pulsed beam Time structure Both muon and electron flavors E"~30)MeV (up to 50)MeV) !! ! !! ! All flavors E"≲16 MeV pp and B8 neutrinos mainly 235U239Pu 238U 241Pu 238U(n,γ)239U 02468 0.0 0.5 1.0 1.5 2.0 2.5 3.0 Eν[MeV] Reactor νe[MeV-1fission-1] pp 13N 8B 15O 17F hep 7Be(384.3keV) 7Be(861.3 keV) pep eN eO+eF Total 0.1 0.5 1 5 10 50 0.1 1000 107 1011 Eν[MeV] Neutrino flux [cm-2s-1MeV-1] νμ νμ νe 0 10 20 30 40 50 1011 1012 1013 1014 1015 Eν[MeV] Neutrino flux [MeV-1cm-2SNS-yr-1] NPOT=3.198·1023 r=0.0848 L=19.3 m 2 Solar Neutrinos Nicola Cargioli – INFN Cagliari Low-energy windows into the electromagnetic properties of neutrinos Neutrino interactions at low energy: CEvNS CEvNS: Coherent Elastic Neutrino-Nucleus Scattering •Weak-neutral-current process •“Coherency”: the nucleons respond as a whole •✅“Large” cross section (∝ .#) •Flavor-blind at tree level The de Broglie wavelength of the /$boson is of the order of the nuclear radius 01%≲ 1 Low momentum transfer (MeV scale) needed, MeV scale neutrinos required! ❌The outcome is a tiny nuclear recoil From EPL 143 (2023) 3, 34001 νe- νe-e-Cs Ar Ge I IBD Pb νeNIN 10 20 30 40 50 0.001 0.010 0.100 1 10 Eν[MeV] σprocess [10-38 cm2] +,!"#$%(.#,0&') +0&' ≅3( )4$ 51−4$0&' 2.# )7* +sin);,<=->)+7* &@=$>)) SM vector proton coupling: Weinberg angle SM vector neutron coupling Proton Form Factor Neutron Form Factor Nuclear recoil energy Neutrino energy Mass of the target nucleus 3 See M. Atzori Corona’s poster Nicola Cargioli – INFN Cagliari Low-energy windows into the electromagnetic properties of neutrinos Neutrino interactions at low energy: vES !ES: "eutrino-Electron Elastic Scattering dσ#ℓ. /011 E2,T1' dT1≅G3 )'m1 2π g4 2ℓ+g5 2ℓ)+g4 2ℓ−g5 2ℓ)1−T1 E2 )−g4 2ℓ)−g5 2ℓ)m1T1 E2 ) Electron recoil energy Electron mass SM vector coupling SM axial coupling For free electrons multiplying for the atomic number Z For bound electron ? ZZeff Ar Ge Xe 0.1 0.5 1 5 10 50 10 50 100 500 1000 Te[keV] (a) dσν-edTe [10 -48 cm2] Eν=30 MeV νe-eZZeff Ar Ge Xe 0.1 0.5 1 5 10 50 Te[keV] ( b ) Eν=30 MeV νμ-e- ! Finally Free Easiest approach: Free Electron Approximation (FEA) modified via a stepping function /&'' 2! This accounts for the effective number of electrons that can be ionized by a certain energy deposit 2! (!""(*#)is specific for each atom <latexit sha1_base64="Brs6wvxEwzJR6E49suZQluBRRGg=">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</latexit> dFEA ⌫`e dTe (E,Te)=Ze↵(Te)dfree ⌫`e dTe (E,Te)+Ze↵(Te)dMM,free ⌫`e dTe (E,Te) " " 4 Nicola Cargioli – INFN Cagliari Low-energy windows into the electromagnetic properties of neutrinos Let’s first check the SM: radiative corrections RGE formalism in Erler & Su, arXiv 1303.5522 (2013) One flavor dependent radiative term: related to the so-called Neutrino Charge Radius (NCR) NC et al., JHEP 05 (2024) 271 At increasing precision, one needs to consider radiative corrections due to higher-order vertex contributions 5 •The neutrino CR affects the scattering of neutrinos with charged particles •Effectively we can see the NCR contribution as an effective shift of the weak mixing angle •The NCR radiative actually depends on 3,… What does the SM look like according to neutrinos? Nicola Cargioli – INFN Cagliari Low-energy windows into the electromagnetic properties of neutrinos The SM according to neutrinos Reactor (anti-)Neutrinos Accelerators 6 Solar Neutrinos •COHERENT CsI •COHERENT LAr •COHERENT Ge •LSND •LAMPF •BNL-E734 •CHARM-II •CCFR •TEXONO Ge •5GEN •CONUS+ •TEXONO CsI •Lux-Zeplin •PandaX-4T •XENONnT I)=@6 178 −K'@6 9:(model)− ∑;P;@6 <=>" ,178 ) +K−1 ,? )+Q ; P;−1 ,; ) To extract information from the data, we build least chi-square functions 6#: •Source of uncertainties and backgrounds fluctuations •Theoretical predictions calculated at the best of our knowledge (and consistently) •Binned analysis to exploit spectral information D. Akimov et al. Phys.Rev.Lett. 129 (2022) 8,081801 D. Akimov et al. Phys.Rev.Lett. 126 (2021) 1, 012002 S. Adamski et al. Phys.Rev.Lett. 134 (2025) 23, 231801 L.B. Auerbach et al. Phys.Rev.D 63, 112001 (2001) R.C. Allen et al. Phys.Rev.D 47, 11 (1993) L. Ahrens et al. Phys.Rev.D41,3297 (1990) P.Vilain et al. Phys.Lett. B 345, 115 (1995) K.S. McFarland et al. Eur.Phys.J. C 1, 509 (1998) S. Karmakar et al. Phys.Rev.Lett. 134 (2025) 12, 121802 V. Belov et al., Chin.Phys. C 49 (2025) 5, 053004 N. Ackermann et al. Nature 643, 1229-1233 (2025) M. Deniz et al. Phys.Rev.D 81, 072001 (2010) J. Aalbers et al. Phys.Rev.Lett. 135,011802 (2025) Z. Bo et al. Phys.Rev.Lett. 133, 191001 (2024), X. Zeng et al. Phys.Rev.Lett. 134, 04001 (2025) E. Aprile et al. Phys.Rev.Lett. 133, 191002 (2024), E. Aprile et al. Phys. Rev.Lett. 129, 161805 (2022) See G. Volta’s talk for details about XENONnT & C. Buck’s talk about CONUS+ CE!NS !ES CE!NS and !ES What does the SM look like according to neutrino DATA? Nicola Cargioli – INFN Cagliari Low-energy windows into the electromagnetic properties of neutrinos Global view on neutral current couplings Global fit of ! − # scattering data from Reactors, Accelerators and Solar neutrinos! 7 The Global fit prefers the degenerate solution (Δ6#≃ 2.1) To be compared to the SM calculation @ 90% CL !!!" (accounting for different momentum transfers and the flavor dependence) Future DM detectors could break the degeneracy! NC et al, Arxiv: 2504.05272 *the fit includes: TEXONO CsI, BNL-E734, CHARM-II, LAMPF, LSND, XENONnT, Lux-Zeplin, PandaX-4T Nicola Cargioli – INFN Cagliari Low-energy windows into the electromagnetic properties of neutrinos The weak mixing angle at low-energies The weak mixing angle, $!, is a key parameter of the SM as it establishes the size of the EW couplings Poorly constrained at low-energies 8 0.1 0.5 1 5 10 50 100 0.1 0.2 0.3 0.4 0.5 Q[MeV] sin2θW CONUS+ TEXONO νGeN COH LAr COH CsI COH Ge XnT (ER) P4T (ER) LZ (ER) XnT (NR) P4T (NR) APV (Cs)Qweak E158 RGE running Particle Thresholds Z pole Exp. 0.001 0.100 10 1000 0.225 0.230 0.235 0.240 0.245 Q[GeV/c] sin2θW(Q) ����� ���� ����� �������� ��� ���� ��� ���(��) g - W + W Z Region probed by CEvNS Region probed by vES NC et al, Arxiv: 2509.22178 g Z f! f" Low-Energy: sensitive to BSM physics Nicola Cargioli – INFN Cagliari Low-energy windows into the electromagnetic properties of neutrinos Global view on CEvNS searches XnT (NR) P4T (NR) CEνNS Comb 0 2 4 6 8 10 0 2 4 6 8 10 Data/SM (ντ) Δχ2 1σ 90% 2σ 99% 3σ 9 Global fit* of ! − $ scattering data from Reactors, Accelerators and Solar neutrinos! Using Solar neutrino data from DM detectors we can probe the % flavor CEvNS era has just started! Large improvements expected soon! NC et al, Arxiv: 2509.04205 @1; CL NC et al, Arxiv: 2509.22178 *the fit includes: COHERENT CsI, COHERENT Ar, COHERENT Ge, CONUS+, nuGeN, TEXONO Ge, XENONnT, PandaX-4T Nicola Cargioli – INFN Cagliari Low-energy windows into the electromagnetic properties of neutrinos Global Status on EC properties ×××××× ×× νeνμνs 10-11 10-10 10-9 Neutrino Type Neutrino Magnetic Moment μν[μB] GEMMA TEXONO CsI CONUS TEXONO CONUS+ MUNU XnT (ER) P4T (ER) LZ (ER) BOREXINO Super-K XMASS KamLand LSND LAMPF BNL-E734 COHERENT ×× ×× νeνμνs 10-14 10-13 10-12 10-11 10-10 10-9 Neutrino Type Neutrino Millicharge qν[e0] GEMMA TEXONO CsI CONUS TEXONO CONUS+ LZ (ER) XnT (ER) P4T (ER) XMASS LSND COHERENT 16 NC et al, Arxiv: 2509.22178 %#"&$ data: -SNS: COHERENT leads to “weak” constraints but is sensitive to ν6 -Future COHERENT Cryogenic detectors will improve of about a factor of 10 -Reactors: lower energies and thresholds, CONUS+ shows good constraints (best on q7:) "#$ data: -Solar: low thresholds and low backgrounds, best constraints on the solar effective parameter! NC et al, Arxiv: 2509.22178 NC et al, PRD 112, 015007 (2025), Arxiv: 2501.18550 NC et al, Arxiv: 2509.04205 NC et al, PRD 112, 015007 (2025), Arxiv: 2501.18550 Nicola Cargioli – INFN Cagliari Low-energy windows into the electromagnetic properties of neutrinos Overview and Conclusions 17 •Low energy neutrinos provide a powerful tool for testing the SM: oWeak Mixing Angle oNeutral-Current neutrino-electron couplings oNeutrino Charge Radius •CEvNS and vES data provide complementary info: we are entering the combined-fit era •The SM is looking good so far •Precision measurement are expected in the next years •Particularly interesting: we can study BSM neutrino properties such as the EM neutrino properties •Reactor antineutrinos and solar neutrinos allow to set the strongest constraints on the MM and EC https://levs-fit.ca.infn.it/ A repository for global analyses at low energies A repository for global analysis at low energies Thanks for your attention https://levs-fit.ca.infn.it/