Eta Photoproduction as a Test of the Extended Chiral Symmetry
arXiv:0706.0616 · doi:10.1016/j.physletb.2007.06.049
Abstract
We analyze the $γp \to ηp$ process from threshold up to 1.2 GeV, employing an effective Lagrangian approach that allows for a mixing of eta couplings of pseudoscalar and pseudovector nature. The mixing ratio of the couplings may serve as a quantitative estimation of the $SU_L(3)\times SU_R(3)$ extended chiral symmetry violation in this energy regime. The data analyzed (differential cross sections and asymmetries) show a preference for the pseudoscalar coupling -- 91% of pseudoscalar coupling component for the best fit. We stress that a more conclusive answer to this question requires a more complete electromagnetic multipole database than the presently available one.
Accepted for publication in Physics Letters B, 1 table, 3 figures