Electromagnetic properties of neutrinos: three new phenomena in neutrino spin oscillations

Abstract

Abstract. In studies of neutrino electromagnetic properties we discuss three very interesting aspects related to neutrino spin oscillations. First we consider neutrino mixing and oscillations in the mass and flavour bases under the influence of a constant magnetic field with nonzero transversal and longitudinal components. Then we discuss the effect of neutrino spin oscillations induced by electroweak interactions of neutrino with moving matter in case there is matter transversal current or polarization. In the final part of the paper we discuss recently developed approach to description of neutrino spin and spin-flavour oscillations in a constant magnetic field that is based on the use of the exact neutrino stationary states in the magnetic field.

Neutrino spin and spin-flavor oscillations in transversal matter currents with standard and nonstandard interactions

“…Recently we have considered in detail [33,41] neutrino mixing and oscillations in the arbitrary constant magnetic field that have B ⊥ and B || nonzero components and derived an explicit expressions for the effective neutrino magnetic moments for the flavor neutrinos in terms of the corresponding magnetic moments introduced in the neutrino mass basis.…”

“…However, it is possible to get a general structure of the effective evolution Hamiltonian for the flavor neutrino using results of our previous studies [33,41] of neutrino oscillations in the arbitrary magnetic field B = B +B ⊥ . For evaluation of the flavor neutrino oscillation in an arbitrary moving matter that is characterized by the current j = j + j ⊥ we consider results for the flavor neutrino oscillations in the magnetic field B and account for similarity of the correspondence between the neutrino magnetic moment to magnetic field interaction Hamiltonian H B ,…”

“…Here n = n0 √ 1−v 2 = n 0 γ n , n 0 is the invariant density of matter composed of neutrons. For the flavor neutrino evolution Hamiltonian in the magnetic field H f B = U H B U † we have [33,41,46]…”

“…For the considered case of ν L e ⇐ (j ⊥B ⊥ ) ⇒ ν R µ from (30) and (33) we get the following neutrino evolution equation…”

Neutrino electromagnetic properties and neutrino oscillations

“…In particular, one might expect manifestations of these effects in astrophysical objects such as magnetars, neutron stars, supernovae, etc., where neutrinos propagate over long distances in the presence of strong magnetic fields. The coupling of neutrino magnetic moments to an external magnetic field can give rise to the phenomenon of neutrino spin-flavor oscillations [6][7][8][9][10][11][12][13][14][15][16][17][18] and, hence, can influence the neutrino fluxes from such astrophysical sources.…”