Investigation of a_(0)-f_(0) mixing

Abstract

We investigate the isospin-violating mixing of the light scalar mesons a_0(980) and f_0(980) within the unitarized chiral approach. Isospin-violating effects are considered to leading order in the quark mass differences and electromagnetism. In this approach both mesons are generated through meson-meson dynamics. Our results provide a description of the mixing phenomenon within a framework consistent with chiral symmetry and unitarity, where these resonances are not predominantly qq̅ states. Amongst the possible experimental signals, we discuss observable consequences for the reaction J/ ψ→Øπ^0 ɳ in detail. In particular, we demonstrate that he effect of a_(0) –f_(0) mixing is by far the most important isospinbreaking effect in the resonance region and can indeed be extracted from experiment.