Pion decay in magnetic fields

TL;DR

This paper studies how background magnetic fields influence the decay of charged pions, revealing new decay channels and quantifying their effects using lattice QCD and perturbative calculations.

Contribution

It introduces a novel analysis of pion decay in magnetic fields, including the identification of a new decay channel and the calculation of decay constants.

Findings

Magnetic fields open a new decay channel for charged pions.

Decay constants depend on magnetic field strength.

Total decay rate is computed perturbatively.

Abstract

The leptonic decay of the charged pion in the presence of background magnetic fields is investigated using quenched Wilson fermions. It is demonstrated that the magnetic field opens up a new channel for this decay. The magnetic field-dependence of the decay constants for both the ordinary and the new channel is determined. Using these inputs from QCD, we calculate the total decay rate perturbatively.