Is there a narrow $N(1685)$?

Abstract

The helicity-dependent observable $E$ for the reaction $\gamma d\to \eta n(p)$ with a spectator proton was recently measured by the A2 Collaboration at MAMI in Mainz. The data were interpreted as further evidence for a narrow resonance with spin and parity $J^P=1/2^{+}$ ($P_{11}$ wave). However, a full partial wave analysis without any narrow resonance leads to an excellent description of the data, imposing a narrow resonance with the properties suggested by the A2 Collaboration leads to a significant deterioration of the fit quality: there is no need for a narrow resonance.

3 pages, 4 figures

References in corpus (11)

• Evidence for a narrow structure at W~1.68 GeV in eta photoproduction on the neutron
• eta-photoproduction in the resonance energy region
• Quasi-free photoproduction of eta-mesons of the neutron
• Quasifree photoproduction of $\eta$ mesons off protons and neutrons
• Photoproduction of eta-mesons on the deuteron above S11(1535) in the presence of a narrow P11(1670) resonance
• Photoproduction of $\eta$ mesons off neutrons from a deuteron target
• Photoproduction of eta meson within a coupled-channels K-matrix approach
• Evidence for Narrow N*(1685) Resonance in Quasifree Compton Scattering on the Neutron
• Insight into the narrow structure in {\boldmath{$\eta$}}-photoproduction on the neutron from helicity dependent cross sections
• New Narrow Nucleon N*(1685)
• Evidence for narrow resonant structures at $W\approx 1.68$ and $W\approx 1.72$ GeV in real Compton scattering off the proton

Cited by in corpus (9)

• Cross Section for $\gamma n\to {\pi }^{0}n$ measured at Mainz/A2
• On the Photoproduction Reactions $\gamma d\to \pi NN$
• Photo- and electro-production of narrow exotic states: from light quarks to charm and up to bottom
• $K^0\Lambda$ photoproduction off the neutron with nucleon resonances
• Observation of a structure in the M${}_{p\eta }$ invariant mass distribution near 1700 MeV/$c^2$ in the $\gamma \mathbf{p}\to \mathbf{p}{\pi }^0\eta$ reaction
• Effects of nucleon resonances on $\eta$ photoproduction off the neutron reexamined
• Compton scattering off proton in the third resonance region
• Search for the $N$(1685) in $\eta \pi$-Photoproduction
• Complete basis for the pentaquark wave function in a group theory approach