Chiral Logs in the Presence of Staggered Flavor Symmetry Breaking

Abstract

Chiral logarithms in $m_{\pi }^2$ are calculated at one loop, taking into account the leading contributions to flavor symmetry breaking due to staggered fermions. I treat both the full QCD case (2+1 light dynamical flavors) and the quenched case; finite volume corrections are included. My starting point is the effective chiral Lagrangian introduced by Lee and Sharpe. It is necessary to understand the one-loop diagrams in the ``quark flow'' picture in order to adjust the calculation to correspond to the desired number of dynamical quarks.

Comments: version to be published in Phys Rev D: clarifications of finite size corrections and chiral fits added; typo in eq.(5) corrected. 27 pages, 5 eps figures