How resonances can synchronize with thresholds
Abstract:The mechanism by which a threshold may capture a resonance is examined. It involves a threshold cusp interfering constructively with either or both (i) a resonance produced via confinement, (ii) attractive t- and u-channel exchanges. The f0(980), X(3872) and Z(4430) are studied in detail. The f0(980) provides a valuable model of the locking mechanism. The X(3872) is too narrow to be fitted by a cusp and requires either a resonance or virtual state. The Z(4430) can be fitted as a resonance but also can be fitted successfully by a cusp with no nearby resonant pole.
Document Type: Research Article
Publication date: July 1, 2008