SU(4)-flavor symmetry breaking in hadron couplings

Abstract

We present results of two studies examining the accuracy of SU(4)-flavor symmetry relations between hadron couplings. Initially, we discuss results obtained with a 3P0 quark-pair creation model with hadron wave functions obtained from a nonrelativistic quark model. Next, we contrast the 3P0 results with those obtained in a framework in which all elements are constrained by studies of Dyson-Schwinger and Bethe-Salpeter equations in QCD. We focus on the three-meson couplings ρπ π, ρKK, and ρDD and meson-baryon couplings π NN, KΛN and DΛcN. Within the 3P0 model, we find that the SU(4) breaking is at most 30% in the charm sector, f or the three-meson and meson-baryon couplings. Within the relativistic Dyson-Schwinger-Bethe-Salpeter framework, the breaking is large in the charm sector, of the order of 300% for the three-meson couplings, but the predicted form factors are much softer than those usually used in meson-exchange models. Consequences of these findings for the predictions of DN cross-sections and of exotic nuclear bound states of J/ψ or heavy-light D and D* mesons are discussed. © Copyright owned by the author(s).