Study of π^{-}p \to ηn at low energies in a chiral constituent quark model

Abstract

A chiral quark model approach is extended to the study of the $\ddot{I}€N$ scattering at low energies. The process of $\ddot{I}{€}^{-}p\to \hat{I}\cdot n$ near threshold is investigated. The model is successful in describing the differential cross sections and total cross section near the $\hat{I}\cdot$ production threshold. The roles of the resonances in $n\le 2$ shells are clarified. Near threshold, the $S_{11}(1535)$ dominates the reactions, while the interferences from the $S_{11}(1650)$ turn out to be destructive around $W\lesssim 1.6$ GeV. The $D_{13}(1520)$ is crucial to give correct shapes of the differential cross sections. The nucleon pole term contributions are significant. The $P_{11}(1710)$ plays an important role around the c.m. energy $W=1.7$ GeV, it is crucial to produce an enhancement in the region of $W>1.6$ GeV as suggested by the data for total cross section. The $t$-channel is negligible in the reactions.

17 pages, 5 figures. Version accepted by PRC. Some changes in the t-channel due to an error in the code