The pion mass in finite volume to two loops

Abstract

We evaluate the pion mass in finite volume to two loops within Chiral Perturbation Theory. The results are compared with a recently proposed extension of the asymptotic formula of Luscher. We find that contributions, which were neglected in the latter, are numerically very small at the two-loop level.

Comments: 6 pages, 2 figures, Talk presented at Lattice 2005 (Hadron spectrum and quark masses)