49 research outputs found
Photoproduction off the nucleon revisited: Evidence for a narrow N(1688) resonance?
Revised analysis of beam asymmetry for the photoproduction on
the free proton reveals a structure at GeV. Fit of the
experimental data based on the E429 solution of the SAID partial wave analysis
suggests a narrow ( MeV) resonance. Possible candidates are
, or resonances. The result is considered in
conjunction with the recent evidence for a bump-like structure at GeV in the quasi-free photoproduction on the neutron.Comment: 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.
Evidence for Narrow N*(1685) Resonance in Quasifree Compton Scattering on the Neutron
The first study of quasi-free Compton scattering on the neutron in the energy
range of GeV is presented. The data reveals a narrow
peak at GeV. This result, being considered in conjunction with
the recent evidence for a narrow structure at GeV in the
photoproduction on the neutron, suggests the existence of a new nucleon
resonance with unusual properties: the mass GeV, the narrow width
MeV, and the much stronger photoexcitation on the neutron than
on the proton.Comment: Replaced with the version published in Phys. Rev.