Extracting meson-baryon contributions to the electroexcitation of the $N(1675){\frac{5}{2}}^{-}$ nucleon resonance

Abstract

We report on the determination of the electrocouplings for the transition from the proton to the $N(1675){\frac{5}{2}}^{-}$ resonance state using recent differential cross section data on $ep\to e{\pi }^{+}n$ by the CLAS collaboration at $1.8\le Q^2<4.5$GeV${}^2$. The data have been analyzed using two different approaches, the unitary isobar model and fixed-t dispersion relations. The extracted ${\gamma }^{\ast }p\to N(1675){\frac{5}{2}}^{-}$ helicity amplitudes show considerable coupling through the $A_{1/2}^p$ amplitude, that is significantly larger than predicted three-quark contribution to this amplitude. The amplitude $A_{3/2}^p$ is much smaller. Both results are consistent with the predicted sizes of the meson-baryon contributions at $Q^2\ge 1.8$GeV${}^2$ from the dynamical coupled-channel model.

Comments: 4 pages, 3 figures. arXiv admin note: text overlap with arXiv:1412.0274