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Chiral symmetry breaking and pion decay in a magnetic field

Prabal Adhikari1,2,* and Brian C. Tiburzi3,4,†

  • *Contact author: prabal.adhikari.physics@proton.me
  • †Contact author: btiburzi@ccny.cuny.edu
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Phys. Rev. D 114, 034504 – Published 10 August, 2026

DOI: https://doi.org/10.1103/84zn-16sy

Abstract

The pattern of chiral symmetry breaking is exploited to compute vector and axial-vector pion matrix elements in a uniform magnetic field. Our results are model independent, and thereby constitute low-energy theorems that must be obeyed by QCD in external magnetic fields. Chiral perturbation theory, lattice QCD, and Nambu–Jona-Lasinio results are compared. While there is some tension between chiral perturbation theory and lattice QCD, the tension between low-energy QCD and the Nambu–Jona-Lasinio model is more acute. As an application, the matrix elements are utilized to compute pion decay rates in a magnetic field.

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Phys. Rev. D 114, 034504– Published 10 August, 2026
  • Received 12 June 2024
  • Accepted 23 July 2026
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.

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