Pion charge asymmetries in e +e -?? +? -?

Abstract

We consider the forward-backward pion charge asymmetry for the e +e -?? +? -? process. In addition to the Bremsstrahlung and double resonance contributions, we use four different models to describe the final state radiation at the loop level (Kaon Loop Model, Resonance Chiral Perturbation Theory, Unitarized Chiral Perturbation Theory and Linear Sigma Model) and compare our results with experimental data. � 2011 American Institute of Physics.