Photoproduction off the nucleon revisited: Evidence for a narrow N(1688) resonance?
arXiv:0801.0778 · doi:10.1007/978-3-540-85144-8_33
Abstract
Revised analysis of $Σ$ beam asymmetry for the $η$ photoproduction on the free proton reveals a structure at $W\sim 1.69$ GeV. Fit of the experimental data based on the E429 solution of the SAID partial wave analysis suggests a narrow ($Î\leq 25$ MeV) resonance. Possible candidates are $P_{11}, P_{13}$, or $D_{13}$ resonances. The result is considered in conjunction with the recent evidence for a bump-like structure at $W\sim 1.67 - 1.68$ GeV in the quasi-free $η$ photoproduction on the neutron.
Contribution to the Workshop on the Physics of the Excited Nucleons NSTAR2007, Bonn, Germany, Sept. 5 - 8 2007. To be published in Eur.Phys.J.A