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

Abstract

We study, within phenomenological Lagrangian approach, the possibility that the near-threshold peak found in the phi-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 D13(2080). The resonance is further found to be able to improve the theoretical description of omega photoproduction against a new set of data if a large value for OZI evading parameter is assumed.