Electromagnetic neutrino: a short review

A short review on selected issues related to the problem of neutrino electromagnetic properties is given. After a flash look at the theoretical basis of neutrino electromagnetic form factors, constraints on neutrino magnetic moments and electric millicharge from terrestrial experiments and astrophysical observations are discussed. We also focus on some recent studies of the problem and on perspectives.Comment: 18 pages in LaTex, two figures, 52 references, based on the oral presentation at the XXXVII International Conference on High Energy Physics, Valencia, Spain, 2-9 July 201

Theory of ionizing neutrino-atom collisions: The role of atomic recoil

We consider theoretically ionization of an atom by neutrino impact taking into account electromagnetic interactions predicted for massive neutrinos by theories beyond the Standard Model. The effects of atomic recoil in this process are estimated using the one-electron and semiclassical approximations and are found to be unimportant unless the energy transfer is very close to the ionization threshold. We show that the energy scale where these effects become important is insignificant for current experiments searching for magnetic moments of reactor antineutrinos.Comment: 7 pages in LaTex, 9 references, based on the poster presentation at the XXXVII International Conference on High Energy Physics, Valencia, Spain, 2-9 July 201

Neutrino-atom collisions

Neutrino-atom scattering provides a sensitive tool for probing nonstandard interactions of massive neutrinos in laboratory measurements. The ionization channel of this collision process plays an important role in experiments searching for neutrino magnetic moments. We discuss some theoretical aspects of atomic ionization by massive neutrinos. We also outline possible manifestations of neutrino electromagnetic properties in coherent elastic neutrino-nucleus scattering.Comment: 5 pages, submitted to proceedings of TAUP 201

New astrophysical limit on neutrino millicharge

An impact of a nonzero neutrino millicharge in astrophysics is tested. It is shown that in astrophysical environments electromagnetic interactions of the neutrino millicharge with strong electromagnetic fields as well as weak interactions of the neutrinos with dense background matter can produce new phenomena accessible for astrophysical observations. On this basis a new limit on the neutrino millicharge $q_0<1.3\times10^{-19}e_0$ is obtained. This limit is among the strongest astrophysical constraint on the neutrino millicharge. Some other possible applications of the obtained results to astrophysics are discussed in details.Comment: 6 pages in LaTex, 19 references, based on the poster presentation at the XXXVII International Conference on High Energy Physics, Valencia, Spain, 2-9 July 201

Electromagnetic properties of massive neutrinos in low-energy elastic neutrino-electron scattering

A thorough account of electromagnetic interactions of massive neutrinos in the theoretical formulation of low-energy elastic neutrino-electron scattering is given. The formalism of neutrino charge, magnetic, electric, and anapole form factors defined as matrices in the mass basis is employed under the assumption of three-neutrino mixing. The flavor change of neutrinos traveling from the source to the detector is taken into account and the role of the source-detector distance is inspected. The effects of neutrino flavor-transition millicharges and charge radii in the scattering experiments are pointed out.Comment: 16 pages, revtex; misprints in Eqs. (22), (29), and (32) corrected (along with other minor misprints throughout

Electromagnetic interactions of neutrinos in processes of low-energy elastic neutrino-electron scattering

Electron energy and angular distributions in the process of low-energy elastic neutrino-electron scattering are treated in the free-electron approximation. The effects of the millicharges, magnetic, electric, and anapole moments of massive neutrinos along with the flavor change of neutrinos traveling from the source to the detector are taken into account under the assumption of three-neutrino mixing. The footprints of neutrino electromagnetic interactions in the electron energy and angle distributions are discussed.Comment: 5 pages, based on the presentation at TAUP 201

Neutrino magnetic moment, millicharge and charge radius

A brief overview of neutrino electromagnetic properties is presented from a theoretical perspective. Their potential effects on coherent elastic neutrino-nucleus scattering are outlined.Comment: 4 pages, to appear in proceedings of NOW 201

Neutrinos, Electrons and Muons in Electromagnetic Fields and Matter: The Method of Exact Solutions

We present a powerful method for exploring various processes in the presence of strong external fields and matter. The method implies utilization of the exact solutions of the modified Dirac equations which contain the effective potentials accounting for the influences of external electromagnetic fields and matter on particles. We briefly discuss the basics of the method and its applications to studies of different processes, including a recently proposed new mechanism of radiation by neutrinos and electrons moving in matter (the spin light of the neutrino and electron). In view of a recent "prediction" of an order-of-magnitude change of the muon lifetime under the influence of an electromagnetic field of a CO$_2$ laser, we revisit the issue and show that such claims are nonrealistic.Comment: 5 pages, talk given by A.I.S. at "Challenges in Particle Astrophysics" Conference (XXth Rencontres de Blois 2008

Spin light of relativistic electrons in neutrino fluxes

A new mechanism of electromagnetic radiation by electrons under the influence of a dense neutrino flux, termed "the spin light of electron" in neutrino flux ($SLe_\nu$), is considered. It is shown that in the case when electrons are moving against the neutrino flux with relativistic energy there is a reasonable increase of the efficiency of the energy transfer from the neutrino flux to the electromagnetic radiation by the $SLe_\nu$ mechanism. The proposed radiation process is applied to an astrophysical environment with characteristics peculiar to supernovae. It is shown that a reasonable portion of energy of the neutrino flux can be transferred by the $SLe_\nu$ to gamma-rays .Comment: 8 pages in LaTex, one figure, 23 references, based on the poster presentation at the XXXVII International Conference on High Energy Physics, Valencia, Spain, 2-9 July 201

New bounds on neutrino electric millicharge from GEMMA experiment on neutrino magnetic moment

Using the new limit on the neutrino anomalous magnetic moment recently obtained by GEMMA experiment we get an order-of-magnitude estimation for possible new direct upper bound on the neutrino electric millicharge $\mid q_{\nu} \mid \sim 1.5 \times 10^{-12} e_0$ ($e_0$ is the absolute value of the electron charge) by comparing the neutrino magnetic moment and millicharge contributions to the total cross section at the electron recoil energy threshold of the experiment. This estimation is confirmed by the performed analysis of the GEMMA data using established statistical procedures and a new direct bound on the neutrino millicharge absolute value $\mid q_{\nu} \mid < 2.7 \times 10^{-12} e_0 \ (90\% CL)$ is derived. This limit is more stringent than the previous one obtained from the TEXONO reactor experiment data that is included to the Review of Particle Properties 2012.Comment: 8 pages in LaTex, one figure, 15 references, based on the poster presentation at the XXXVII International Conference on High Energy Physics, Valencia, Spain, 2-9 July 201