The near-threshold peak of the Φ-photoproduction cross section and its interpretation

摘要

We study, within phenomenological Lagrangian approach, the possibility that the near-threshold peak found in the Φ-photoproduction cross section is caused by a resonance. We show that, by employing a J~P = 3/2~- resonance with a mass of 2.08 ± 0.05 GeV and a width of 0.570 ± 0.169 GeV, the LEPS data which include new data on nine spin-density matrix elements can indeed be described reasonably well. We also find that the ratio of helicity amplitudes A_(1/2)/A_(3/2) calculated from the resulting coupling constants differs in sign from that of D_(13)(2080). The resonance is further found to be able to improve the theoretical description of ω photoproduction against a new set of data if a large value for OZI evading parameter is assumed.