Charged pion electric polarizability from lattice QCD

TL;DR

This paper calculates the electric polarizability of charged pions using lattice QCD with a background field method, ensuring gauge invariance and applying it to multiple ensembles to obtain results at a specific pion mass.

Contribution

It introduces a gauge-invariant lattice QCD methodology for computing charged pion electric polarizability using background fields and correlator fitting.

Findings

Extracted pion electric polarizability at 315 MeV pion mass.

Developed a fitting procedure for correlator analysis.

Ensured gauge invariance in the methodology.

Abstract

We present a calculation of the charged pion electric polarizability using the background field method. To extract the mass-shift induced by the electric field for the accelerated charged particle we fit the lattice QCD correlators using correlators derived from an effective model. The methodology outlined in this study (boundary conditions, fitting procedure, etc.) is designed to ensure that the results are invariant under gauge transformations of the background field. We apply the method to four $N_f=2$ dynamical ensembles to extract $\alpha_{\pi^\pm}$ at pion mass of $315$ MeV.