Phenomenology of $\phi$ photoproduction from recent CLAS data at Jefferson Lab

Abstract

We comment on the important phenomenological aspects of the recent high-statistics and wide-angle coverage $\phi$ photoproduction data from CLAS at Jefferson Lab. The most prominent feature is a localized structure at a center-of-mass (c.m) energy $\sqrt{s} \sim 2.2$ GeV that is not expected in a simple $t$-channel Pomeron-exchange model. The structure exists only at the forward production angles that almost rules out any resonance contribution. Strong rescattering effects between the $p \phi$ and $K^+\Lambda(1520)$ channels could be possible explanations. The analyses of both charged- ($\phi \to K^+ K^-$) and neutral- ($\phi \to K^0_S K^0_L$) $K\bar{K}$ decay modes of the $\phi$, that show some minor differences, can be illuminating in this respect. We also comment on the angular structure of the Pomeron-parton coupling as borne out in the polarization data where the often-asumed $s$-channel helicity conservation is seen to be broken.