Eur. Phys. J. C (2006) 48: 589-596
https://doi.org/10.1140/epjc/s10052-006-0018-4

Theoretical Physics

Electromagnetic vertex function of the pion at T>0

¹ Fakultät für Physik, Universität Bielefeld, 33615, Bielefeld, Germany
² National Institute for Nuclear Physics and High-Energy Physics (NIKHEF), 1009 DB, Amsterdam, The Netherlands
³ Institute for Theoretical Physics, University of Amsterdam, Valckenierstraat 65, 1018 XE, Amsterdam, The Netherlands

^* e-mail: edwin@physik.uni-bielefeld.de

Received: 23 December 2005
Revised: 4 July 2006
Published online: 24 October 2006

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 non-perturbatively improved Sheikholeslami–Wohlert action is used together with the corresponding improved vector current. The electromagnetic vertex function is extracted for pion masses down to 360 MeV and momentum transfers Q²≤2.7 GeV².