Constraints on 3-flavor QCD order parameters from eta to pi+pi-pi0 decay width

Abstract

Quark condensate and pseudoscalar decay constant in the chiral limit are the principal order parameters of spontaneous chiral symmetry breaking in QCD. Yet their three flavor values are still only weakly constrained by analyses using experimental data. We try to obtain such constraints by statistical methods from the decay width of the eta to pi+pi-pi0 decay in the framework of resummed chiral perturbation theory. We rely on recent estimates of the isospin violating parameter R, which is proportional to the difference of the u and d quark masses. Alternatively, we relax the assumption and try to extract information on R as well.