The pion form factor from first principles

TL;DR

This paper computes the electromagnetic form factor of the pion using quenched lattice QCD with improved actions, exploring pion masses down to 360 MeV and extrapolating results to the physical mass.

Contribution

It presents a first-principles lattice QCD calculation of the pion form factor with non-perturbative improvements and chiral extrapolation techniques.

Findings

Mean square radius consistent with Bethe Salpeter amplitude results

Form factor computed for pion masses down to 360 MeV

Extrapolation towards physical pion mass using quenched chiral perturbation theory

Abstract

We calculate the electromagnetic form factor of the pion in quenched lattice QCD. The non-perturbatively improved Sheikoleslami-Wohlert lattice action is used together with the ${\mathcal O}(a)$ improved current. We calculate form factor for pion masses down to $m_\pi = 360 MeV$. We compare the mean square radius for the pion extracted from our form factors to the value obtained from the 'Bethe Salpeter amplitude'. Using (quenched) chiral perturbation theory, we extrapolate our results towards the physical pion mass.