A chiral quark model approach is extended to the study of the $\\pi
N$ scattering at low energies. The process of $\\pi^{-}p
\\rightarrow \\eta n$ near threshold is investigated. The model is
successful in describing the differential cross sections and total
cross section near the $\\eta$ production threshold. The roles of
the resonances in $n\\leq 2$ 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. |
