Creation of Dirac neutrinos in a dense medium with a time-dependent effective potential

Abstract

We consider Dirac neutrinos interacting with background fermions in the frame of the standard model. We demonstrate that a time-dependent effective potential is quite possible in a protoneutron star (PNS) at certain stages of its evolution. For the first time, we formulate a nonperturbative treatment of neutrino processes in a matter with arbitrary time-dependent effective potential. Using linearly growing effective potential, we study the typical case of a slowly varying matter interaction potential. We calculate differential mean numbers of νν pairs created from the vacuum by this potential and find that they crucially depend on the magnitude of masses of the lightest neutrino eigenstate. These distributions uniformly span up to ∼ 10 eV energies for muon and tau neutrinos created in PNS core due to the compression just before the hydrodynamic bounce and up to ∼ 0.1 eV energies for all three active neutrino flavors created in the neutronization. Considering different stages of the PNS evolution, we derive constraints on neutrino masses, mν (10 −8 − 10 −7 ) eV, corresponding to the nonvanishing νν pairs flux produced by this mechanism. We show that one can distinguish such coherent flux from chaotic fluxes of any other origin. Part of these neutrinos, depending on the flavor and helicity, are bounded in the PNS, while antineutrinos of any flavor escape the PNS. If the created pairs are νeνe, then a part of the corresponding neutrinos also escape the PNS. The detection of ν andν with such low energies is beyond current experimental techniques.

Electroweak Interaction of Particles With Accelerated Matter and Astrophysical Applications

“…The obtained upper bound is comparable with the constraint on neutrino masses established earlier in Ref. [10], where we studied the νν pairs creation in SN at the neutronization.…”

Neutrino spin oscillations in external fields in curved spacetime

“…1(a), we predict the oscillations length L comparable with the outer radius of an accretion disk [47] only for very low energy neutrinos with E = 10 eV. Nevertheless the creation of such neutrinos is anticipated in matter with time dependent density [46].…”

“…If we suppose that the emission of low energy neutrinos happens owing to the time dependence of the effective number density of NS, as in Ref. [46], the duration of the neutrino pulse is ∼ 10 −3 s. According to up-to-date observations [17], a typical time scale of a GW wave packet is ∼ 10 −1 s. Thus, these neutrinos are very well localized inside such a wave packet. Thus, in the first approximation, in our studies of neutrino oscillations driven by GW, we can neglect the time dependence of the frequency and the amplitude of GW (the GW chirp), observed by the modern GW detectors [17].…”

“…Note that the creation of low energy Dirac neutrinos with E 10 eV in matter with a time dependent density was studied in Ref. [46]. The outer radius of an accretion disk for BH with the mass 10M was found in Ref.…”

Exactly solvable cases in QED with t-electric potential steps

“…[19][20][21], in the case of T -constant electric field in Refs. [20,[22][23][24][25][26][27][28][29][30], and in the case of exponential electric fields in Refs. [31,32].…”