Electromagnetic vertex function of the pion at T > 0

Abstract

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

Comments: 17 pages, 8 figures