The Pion Form Factor on the Lattice at Zero and Finite Temperature

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 consistently ${\cal O}(a)$-improved current. We calculate the pion form factor for masses down to mπ = 360 MeV, extract the charge radius, and extrapolate toward the physical pion mass. In the second part, we discuss results for the pion form factor and charge radius at 0.93 Tc and compare with zero temperature results.