Electromagnetic vertex function of the pion at T > 0

TL;DR

This study computes the electromagnetic vertex function of the pion at temperatures close to the critical temperature using quenched lattice QCD, providing insights into pion structure under thermal conditions.

Contribution

It presents the first lattice QCD calculation of the pion's electromagnetic vertex function at finite temperature near T_c.

Findings

Electromagnetic vertex function extracted for pion masses down to 360 MeV.

Results obtained for momentum transfers up to 2.7 GeV^2.

Uses nonperturbatively improved lattice actions for accurate results.

Abstract

The matrix element of the electromagnetic current between pion states is calculated in quenched lattice QCD at a temperature of $T = 0.93 T_c$. The nonperturbatively improved Sheikholeslami-Wohlert action is used together with the corresponding ${\cal O}(a)$ improved vector current. The electromagnetic vertex function is extracted for pion masses down to $360 {\rm MeV}$ and momentum transfers $Q^2 \le 2.7 {\rm GeV}^2$.