The matrix element of the electromagnetic current between pion states is calculated in quenched lattice QCD at a temperature of T=0.93Tc. The nonperturbatively improved Sheikholeslami-Wohlert action is used together with the corresponding O(a) improved vector current. The electromagnetic vertex function is extracted for pion masses down to 360MeV and momentum transfers Q2≤2.7GeV2.
@article{arxiv.hep-lat/0512035,
title = {Electromagnetic vertex function of the pion at T > 0},
author = {J. van der heide and J. H. Koch and E. Laermann},
journal= {arXiv preprint arXiv:hep-lat/0512035},
year = {2011}
}