Spin flavor oscillation of neutrinos in rotating gravitational fields and their effects on pulsar kicks

Abstract

The origin of high velocities of pulsars is studied by considering the spin-flip conversion of neutrinos propagating in a gravitational field of a protoneutron star. For a rotating gravitational source (such as pulsars) with angular velocity , one finds that the spin connections (entering in the Dirac equation written in curved space time) induce an additional contribution to neutrino energy which is proportional to ω · p, with p the neutrino momentum. Such a coupling (spin-gravity coupling) can be responsible of pulsar kicks being the asymmetry of the neutrino emission generated by the relative orientation of the neutrino momentum p with respect to the angular velocity ω. As a consequence, the mechanism suggests that the motion of pulsars is correlated to their angular velocity ω. In this work we consider neutrinos propagating orthogonally to the magnetic field. The fractional asymmetry turns out to be independent on the magnetic field of the nascent protostar, and is only related to the angular velocity (∆p/p ∼ ω). As in the usual approaches, spin flip conversion is generated via the coupling of the neutrino magnetic momentum with the magnetic field. For our estimations, we use the large non-standard neutrino magnetic momentum provided by astrophysical and cosmological constraints, µν ∼ 10 −11 µB. -The connection with recent observations and statistical analysis is also discussed.

Neutrino spin flip around a Schwarzschild black hole

“…The magnetic moment µ can be evaluated theoretically to one-loop level, yielding µ = 2.7 × 10 −10 µ B (m ν /m N ), where µ B = 9.27 × 10 −21 erg G −1 is the Bohr magneton, m ν ∼ 1 eV/c 2 is a typical bound on the neutrino mass and m N is the nucleon mass. On the other hand, astrophysical and/or experimental data seem to suggest an upper bound, about 10 −11 µ B [1,13]. So, there is a wide range of uncertainty about µ: 10 −19 µ 10 −11 , or so.…”

“…where = ±1, depending on the relative sign of the magnetic interaction with respect to the gravito-inertial G 2 -term. From (5.6) we get the desired Hamiltonian: Ĥ = Ĥ0 − e −W (G 2 α 2 γ 5 + µB 2 βσ 13 ).…”

“…The choice of the tetrad, when adapted to some physical reference frame, can be actually related to non-inertial effects [9,10]. When discussing neutrino oscillations in curved spacetimes, for the sake of convenience, calculations are usually carried on employing a static tetrad frame [5,6] or a fiducial (e.g., ZAMO) tetrad, in the case of a rotating gravitational source [11][12][13]. This appears to be indeed a useful tool, thanks to its simple formulation, although its physical relevance could give rise to some doubts.…”

Neutrino Mass Spectrum from Gravitational Waves Generated by Double Neutrino Spin‐Flip in Supernovae

“…5 The anisotropy of the outgoing neutrinos is also related to the energy flux F s emitted by the PNS and, in turn, to the fractional momentum asymmetry Ájpj/jpj ( Kusenko & Segré 1996;Barkovich et al 2002;Lambiase 2005aLambiase , 2005bMosquera Cuesta & Fiuza 2004). To compute F s , one has to take into account the structure of the flux at the resonant surface, which acts as an effective emission surface, and the distribution in the diffusive approximation ( Barkovich et al 2002)…”

Pulsar kicks induced by spin flavour oscillations of neutrinos in gravitational fields

“…These limits do not apply to sterile neutrinos (they may have only a small mixing angle with the ordinary neutrinos; Kusenko & Segré 1997; Fuller et al 2003). Papers dealing with the origin of pulsar kicks can be found in Kusenko & Segré (1999), Akhmedov, Lanza & Sciama (1997), Barkovich, D'Olivo & Montemayor (2004), Barkovich et al (2001), Burrows & Hayes (1996), Chandra, Goyal & Goswami (2002), Chugai (1984), Mosquera Cuesta (2000, 2002), Mosquera Cuesta & Fiuzza (2004), Dorofeev, Rodionov & Ternov (1984), Duncan & Thompson (1992), Elizalde, Ferrer & de la Incera (2002, 2004), Erdas & Feldman (1990), Goyal (1999), Grasso, Nunokawa & Valle (1998), Gott, Gunn & Ostriker (1970), Harrison & Tademaru (1975), Horvat (1998), Janka & Raffelt (1998), Lai & Qian (1998), Lambiase (2005a,b), Loveridge (2004), Nardi & Zuluga (2001), Qian (1997) and Voloshin (1988).…”