Axion decay in a strong magnetic field

Abstract

The axion decay into charged fermion-antifermion pair a → ff is studied in external crossed and magnetic fields. The result we have obtained can be of use to re-examine the lower limit on the axion mass in case of possible existence of strong magnetic fields at the early Universe stage.will be published in Phys. Lett. B

Field-induced axion decay a → e+e− via plasmon

“…It is interesting to compare (13) with the fieldinduced axion lifetime [15] in the model [16] where axions couple with electrons on the tree level: . The expressions (13) and (14) we have presented here demonstrate the strong catalyzing influence of the medium, plasma and the magnetic field, on the axion lifetime in comparison with the vacuum one (2).…”

Field-induced axion decay a→e+e− in plasma

“…In particular, the axion decay into electron-positron pair a → e + e − is opened due to a specific kinematics of charged particles in the field. We have studied this decay in two classes of invisible axion models [14,15]. It was shown [14] that the axion lifetime in DFSZ model is reduced to 10 5 s in the case of the decaying axion energy ∼ 1 MeV in the magnetic field of strength ∼ 10 15 G while for KSVZ axions the lifetime becomes even of order seconds [15] for the above mentioned parameters.…”

“…However considering axions effects in astrophysical and cosmological environments it is important to take into account not only the magnetic field influence, as it was done in [14,15], but the plasma one as well. The most physically realistic situation is that when from both components of the active medium the plasma dominates.…”

Axion Decay of a Photon in an External Electromagnetic Field

“…It is known that an external electromagnetic field plays the role of an active medium in its influence on particle properties. Due to a nontrivial kinematics of charged particles and a photon dispersion in the external field, such axion processes as the axion decay into electron-positron pair a → e + e − [9,10], the axion cyclotron emission e → ea [11,12] are not only opened kinematically but also become substantial.…”