Magnetic field effect on the decay process of a neutral scalar boson to charged fermions

Abstract

The effect of a homogeneous weak magnetic field on the decay process of a neutral scalar particle to a pair of charged fermions is studied. The decay rate is calculated through the imaginary part of the self‐energy of the scalar particle interacting with the charged fermions, at one loop. The weak field approximation can be performed in different ways, depending on the hierarchy of scales. Here, we explore the regime where the progenitor particle has a high transverse momentum and we find that the process is favored by the increase of the magnetic field. We compare our results with recent findings for a different kinematical regime and briefly discuss the possible physical reasons for the different behaviors. The phenomenon can be relevant in early universe events or in high‐energy collisions.