Pion decay constants in a strong magnetic field

TL;DR

This paper investigates how magnetic fields affect pion decay constants using an effective quark-antiquark model that respects fundamental chiral relations, revealing distinct behaviors for charged and neutral pions in strong fields.

Contribution

It provides a theoretical analysis of pion decay constants in magnetic fields, demonstrating specific dependence patterns in the strong field regime, consistent with chiral symmetry considerations.

Findings

Neutral pion decay constant scales as √(e_qB/σ) in strong fields

Charged pion decay constant decreases as √(σ/e_qB) in strong fields

Model respects Gell-Mann--Oakes--Renner relations at zero field

Abstract

Decay constants of the charged and neutral pions in magnetic field are considered in the framework of the effective quark-antiquark lagrangian respecting Gell-Mann--Oakes--Renner (GOR) relations at zero field. The $\sqrt{\frac{e_qB}{\sigma}}$ dependence is found in strong fields $e_qB\gg \sigma$ for the neutral pion, while the charged pion constant decreases as $\sqrt{\frac{\sigma}{e_qB}}$.