Total widths of light hadrons: an inclusive view

Abstract

The total width of a qq̅ hadron is modeled by the rate at which it dissociates into a pair of quasifree quarks brought about by "soft" and "hard" gluon exchanges, under the ansatz of a short time zone for the existence of such a state. A crucial ingredient in this regard is the quark's mass function for which a nonperturbative formula is obtained via dynamical breaking of the chiral symmetry of an input vector-exchange-like four-fermion Lagrangian, facilitated by the knowledge that for a chirally invariant Lagrangian this quantity is also equal to the pion-quark vertex function in the chiral limit (M_p⇒0). The mass function so employed is based on a Bethe-Salpeter (BS) model with a vectorexchange-like kernel (chirally invariant) which is precalibrated to the spectroscopy of qq̅ and qqq hadrons, and also predicts a value of <qq̅>o fully consistent with QCD sum rules. The predicted widths show a good overlap with available data from L> 1 to J=5, while limitations of phase space resist applicability of the said mechanism due to the onset of hadronic selection rules for certain L≤1 states.