φ-meson photoproduction off the protons by using linearly polarized photons in the mid- to higher-t regimes at threshold energies

Abstract

Observables from vector meson photoproduction by linearly-polarized photons can be expressed in term of bilinear combinations of helicity amplitudes parameterized by the Spin Density Matrix Elements (SDMEs). These SDMEs give straightforward relations for understanding the nature of the parity exchange at threshold energies, as well as for extracting signatures of the Okubo-Zweig-Iizuka violation. This paper will show preliminary measurements of SDMEs for γ⃗p → φp in the photon energy range of 1.7 to 1.9 GeV (momentum transfer squared t range of −1.2 to −0.25 GeV2) and 1.9 to 2.1 GeV (t range of −1.4 to −0.25 GeV2) from the g8b experimental data collected in the summer of 2005 in the Hall B of Jefferson Lab.