Electromagnetic Properties of Neutrinos

Abstract

A review of theory and phenomenology of neutrino electromagnetic properties is presented. A massive neutrino even in the easiest generalization of the Standard Model inevitably has nonzero electromagnetic characteristics, at least nonzero magnetic moment. Although its value, determined by the neutrino mass, is very small, in other BSM theories much larger values of magnetic moments are predicted. A short introduction to the derivation of the general structure of the electromagnetic interactions of Dirac and Majorana neutrinos is presented. A thorough account of electromagnetic interactions of massive neutrinos in the theoretical formulation of low-energy elastic neutrino-electron scattering is discussed on the basis of our recently published paper. The formalism of neutrino charge, magnetic, electric, and anapole form factors defined as matrices in the mass basis with account for three-neutrino mixing is presented. Then we discuss experimental constraints on neutrino magnetic and electric dipole moments, electric millicharge, charge radius and anapole moments from the terrestrial laboratory experiments. A special credit is done to bounds on neutrino electromagnetic characteristics (including magnetic and electric dipole moments, millicharge and charge radius) obtained by the reactor (MUNU, TEXONO and GEMMA) and solar Super-Kamiokande and the recent Borexino and COHERENT experiments. The effects of neutrino electromagnetic interactions in astrophysical and cosmological environments are also reviewed. The main manifestation of neutrino electromagnetic interactions, such as: 1) the radiative decay in vacuum, in matter and in a magnetic field, 2) the Cherenkov radiation, 3) the plasmon decay, 4) spin light in matter, 5) spin and spin-flavour precession, 6) neutrino pair production in a strong magnetic field, and the related processes along with their astrophysical phenomenology are also considered. The best world experimental bounds on neutrino electromagnetic properties are confronted with the predictions of theories beyond the Standard Model. It is shown that studies of neutrino electromagnetic properties provide a powerful tool to probe physics beyond the Standard Model. References: [1] C. Guinti and A. Studenikin, “Neutrino electromagnetic interactions: Awindow to new physics”, Rev. Mod. Phys. 87 (2015) 531-591. [2] A. Studenikin, “Neutrino electromagnetic properties: A window to new physics – II” , PoS (EPS-HEP2017) 137, arXiv:1801.08887. [3] A. Popov, A. Studenikin, “Neutrino oscillations and exact eigenstates in magnetic field”, accepted to Eur. Phys. J. C (2019), arXiv:1803.05755 v2, January 13, 2019. [4] A. Popov, A. Pustoshny, A. Studenikin, “Neutrino motion and spin oscillations in magnetic field and matter currents”, PoS EPS-HEP2017 (2018) 643, arXiv:1801.08911. [5] K. Kouzakov, A. Studenikin, “Electromagnetic properties ofmassive neutrinos in low-energy elastic neutrinoelectron scattering”, Phys. Rev. D 95 (2017) 055013. [6] P. Kurashvili, K. Kouzakov, L. Chotorlishvili, A. Studenikin, “Spin-flavor oscillations of ultrahigh-energy cosmic neutrinos in interstellar space: The role of neutrino magnetic moments”, Phys. Rev. D 96 (2017) 103017. [7] A. Grigoriev, A. Lokhov, A. Studenikin, A. Ternov, “Spin light of neutrino in astrophysical environments”, JCAP 1711 (2017) no.11, 024. [8] P. Pustoshny, A. Studenikin, “Neutrino spin and spin-flavour oscillations in transversal matter currents with standard and non-standard interactions”, Phys. Rev. D 98 (2018) no.11, 113009. [9] M. Cadeddu, C. Giunti, K. Kouzakov, Y.F. Li, A. Studenikin, Y.Y. Zhang, “Neutrino charge radii from COHERENT elastic neutrino-nucleus scattering”, Phys. Rev. D 98 (2018) no.11, 113010. [10] D. Papoulias, T. Kosmas, “COHERENT constraints to conventional and exotic neutrino physics”, Phys. Rev. D 97 (2018) 033003. [11] M. Agostini et al (Borexino coll.), “Limiting neutrino magnetic moments with Borexino Phase-II solar neutrino data”, Phys. Rev. D 96 (2017) 091103. [12] ] S. Arceo-Díaz, K.-P. Schröder, K. Zuber and D. Jack, “Constraint on the magnetic dipole moment of neutrinos by the tip-RGB luminosity in ω-Centauri”, Astropart. Phys. 70 (2015) 1. [13] A. Studenikin, “New bounds on neutrino electric millicharge from limits on neutrino magnetic moment”, Europhys. Lett. 107 (2014) 21001. [14] A. Studenikin, I. Tokarev, “Millicharged neutrino with anomalous magnetic moment in rotating magnetized matter”, Nucl. Phys. B 884 (2014) 396-407. [15] K. Kouzakov, A. Studenikin, “Theory of neutrino-atom collisions: The history, present status and BSM physics”, Adv. High Energy Phys. 2014 (2014) 569409. [16] A. Beda, V. Brudanin, V. Egorov et al., “The results of search for the neutrino magnetic moment in GEMMA experiment”, Adv. High Energy Phys. 2012 (2012) 350150. [17] N. Viaux, M. Catelan, P. B. Stetson, G. G. Raffelt et al., “Particle-physics constraints from the globular cluster M5: neutrino dipole moments”, Astron. & Astrophys. 558 (2013) A12. [18] G. Raffelt, “New bound on neutrino dipole moments from globular-cluster stars“, Phys. Rev. Lett. 64 (1990) 2856. Primary author: Prof. STUDENIKIN, Alexander (M.V. Lomonosov Moscow State University & JINR (RU)) Presenter: Prof. STUDENIKIN, Alexander (M.V. Lomonosov Moscow State University & JINR (RU)) Session Classification: Neutrino Physics Track Classification: Neutrino Physics