Nucleon resonances in the ${\pi }^{-}p\to K^0\Lambda$ reaction near threshold

Abstract

We investigate the two-body reaction ${\pi }^{-}p\to K^0\Lambda$ within the effective Lagrangian approach and the isobar model. In addition to the "background" contributions from $t$-channel $K^{\ast }$ exchange, $u$-channel $\Sigma (1192)$ and ${\Sigma }^{\ast }(1385)$ exchanges, and $s$-channel nucleon pole terms, the contributions from the nucleon resonances $N^{\ast }(1535)$, $N^{\ast }(1650)$, and $N^{\ast }(1720)$ are investigated. It is shown that the inclusion of these nucleon resonances contributions leads to a good description of the experimental total and differential cross sections data at low energy region. The $s$-channel $N^{\ast }(1535)$, $N^{\ast }(1650)$, and $N^{\ast }(1720)$ resonances and the $t$-channel $K^{\ast }$ exchange give the dominant contributions below $W=1.76$ GeV, while the $u$-channel $\Sigma (1192)$ and ${\Sigma }^{\ast }(1385)$ exchanges give the minor contributions.

Comments: Published on Communications in Theoretical Physics