Measuring charged particle polarizabilities on the lattice without background fields

TL;DR

This paper introduces a novel lattice QCD method to compute electromagnetic polarizabilities of charged hadrons without background fields by matching low-energy Compton scattering amplitudes to current-current correlators.

Contribution

It presents a new approach using four-point correlation functions in momentum space to determine hadron polarizabilities directly from lattice QCD simulations.

Findings

Formulas for electric and magnetic polarizabilities derived for pion and proton.

Constructed lattice four-point correlation functions for Monte Carlo simulations.

Highlighted the potential of four-point functions as a versatile tool for hadron structure studies.

Abstract

We show how to compute electromagnetic polarizabilities of charged hadrons without the use of background fields in lattice QCD. The low-energy behavior of the Compton scattering amplitude is matched to matrix elements of current-current correlation functions on the lattice. Working in momentum space, formulas for electric polarizability ($\alpha_E$) and magnetic polarizability ($\beta_M$) are derived for both charged pion and proton. Lattice four-point correlation functions are constructed from quark and gluon fields to be used in Monte-Carlo simulations. We also draw attention to the potential of four-point functions as a multi-purpose tool for hadron structure.