Hadron electric polarizability -- finite volume corrections

TL;DR

This study investigates finite volume effects on the electric polarizability of the neutral pion using lattice simulations, revealing persistent negative polarizability at low pion masses and highlighting challenges in extrapolating to infinite volume.

Contribution

The paper provides a systematic analysis of finite volume corrections for pion polarizability and explores boundary condition effects, addressing previous artifacts in lattice QCD calculations.

Findings

Polarizability remains negative for pion masses below 400 MeV even on larger lattices.

Finite volume corrections are significant and complicate infinite volume extrapolation.

Boundary conditions influence the measured polarizability values.

Abstract

We use the background field method to extract the polarizability for the neutral "pion". In our previous study we found that the polarizability for this system is negative which is believed to be a finite volume artifact. To address this issue, we carry out simulations for different lattice sizes and we also look at the influence of the boundary conditions on these results. We find that for pion masses lower than 400 MeV the polarizability remains negative even on larger lattices. An infinite volume extrapolation is attempted, but the results are not conclusive due mainly to a lack of an analytical form for the finite volume corrections for this system.