Total widths of hadrons from an intrinsic (quark level) standpoint

Abstract

The total width of a qq̅ hadron is modeled by the rate at which it dissociates into two quasi-free quarks of momentum-dependent mass (m_f) determined by 4-momentum conservation. A crucial ingredient in this regard is the quark's mass function for which a non-perturbative formula is obtained via dynamical breaking (à la NJL) of the chiral symmetry of an input vector-exchange-like 4-fermion Lagrangian, under the knowledge that for a chirally invariant Lagrangian this quantity is also equal to the pion-quark vertex function in the chiral limit (M_π → 0). The latter in turn is based on a Bethe-Salpeter (BS) model with a vector-exchange-like kernel (chirally invariant) which is precalibrated to the spectroscopy of qq̅ and qqq hadrons, and also predicts a value of ‹qq̅›₀ fully consistent with QCD sum rules. The predicted widths show a good overlap with available data up to J=5, except for local (hadronic) selection rules which affect at most some L≤1 states.