arXiv subjects

Maxim Dvornikov

Publications and source records attributed to Maxim Dvornikov.

130 records · Page 8Linked to original sources

arXiv2004

Electromagnetic Form Factors of a Massive Neutrino

Electromagnetic form factors of a massive neutrino are studied in a minimally extended standard model in an arbitrary $R_ξ$ gauge and taking into account the dependence on the masses of all interacting particles. The contribution from all Feynman diagrams to the charge, magnetic, and anapole form factors, in which the dependence on the masses of all particles as well as on gauge parameters is accounted for exactly, are obtained for the first time in explicit form. The asymptotic behavior of the magnetic form factor for large negative squares of the momentum of an external photon is analyzed and expression for the anapole moment of a massive neutrino is derived. The results are generalized to the case of mixing between various generations of the neutrino. Explicit expressions are obtained for the charge, magnetic, and electric dipole and anapole transition form factors as well as for the transition electric dipole moment.

hep-ph↗

arXiv2004

Spin light of neutrino in gravitational fields

We predict a new mechanism for the spin light of neutrino ($SLν$) that can be emitted by a neutrino moving in gravitational fields. This effect is studied on the basis of the quasiclassical equation for the neutrino spin evolution in a gravitational field. It is shown that the gravitational field of a rotating object, in the weak-field limit, can be considered as an axial vector external field which induces the neutrino spin procession. The corresponding probability of the neutrino spin oscillations in the gravitational field has been derived for the first time. The considered in this paper $SLν$ can be produced in the neutrino spin-flip transitions in gravitational fields. It is shown that the total power of this radiation is proportional to the neutrino gamma factor to the fourth power, and the emitted photon energy, for the case of an ultra relativistic neutrino, could span up to gamma-rays. We investigate the $SLν$ caused by both gravitational and electromagnetic fields, also accounting for effects of arbitrary moving and polarized matter, in various astrophysical environments. In particular, we discuss the $SLν$ emitted by a neutrino moving in the vicinity of a rotating neutron star, black hole surrounded by dense matter, as well as by a neutrino propagating in the relativistic jet from a quasar.

hep-ph↗

arXiv2004

Electric charge and magnetic moment of massive neutrino

We consider a massive Dirac neutrino electric charge and magnetic moment within the context of the standard model supplied with SU(2)-singlet right-handed neutrino in arbitrary R_ξgauge. Using the dimensional-regularization scheme we start with calculations of the one-loop contributions to the neutrino electromagnetic vertex function exactly accounting for the neutrino and other particles masses. We examine the decomposition of the massive neutrino electromagnetic vertex function and show that it contains only the four form factors. Then we get the closed integral expressions for different contributions to the neutrino electric charge and magnetic form factors. These calculations enable us to follow the neutrino and corresponding charged lepton masses and gauge-fixing parameters dependence. For several one-loop contributions to the neutrino charge and magnetic moment, that were calculated previously by the other authors with mistakes, we find the correct results. We show that the neutrino charge for massive neutrino is a gauge independent and vanishing value in the first two orders of the expansion over the neutrino mass parameter b. In the particular choice of the 't Hooft-Feynman gauge we also demonstrate that the neutrino charge is zero for arbitrary mass of neutrino. For each of the diagrams contributing to the neutrino magnetic moment, we get expressions accounting for the leading and next-to-leading order in b with the gauge dependence shown explicitly. Each of the contributions are finite and the sum of all contributions turns out to be gauge-independent. Our calculations also enable us to get the magnetic moment of a heavy neutrino.

hep-ph↗

arXiv2003

There is no mass squared term in neutrino electric charge

We claim that the neutrino mass squared term cannot appear in the expansion of the neutrino electric charge over the neutrino mass parameter at the one-loop level of the standard model supplied with $\mathrm{SU}(2)$-singlet right-handed neutrino.

hep-ph↗