Role of the $N^{\ast }(2080)$ in $pp\to p{K}^{+}\Lambda (1520)$ and ${\pi }^{-}p\to K^0\Lambda (1520)$ reactions

Abstract

We investigate the $\Lambda (1520)$ hadronic production in the $pp\to p{K}^{+}\Lambda (1520)$ and ${\pi }^{-}p\to K^0\Lambda (1520)$ reactions within the effective Lagrangian method. For ${\pi }^{-}p\to K^0\Lambda (1520)$ reaction, in addition to the "background" contributions from $t-$channel $K^{\ast }$ exchange, $u-$channel ${\Sigma }^{+}$ exchange, and $s-$channel nucleon pole terms, we also consider the contribution from the nucleon resonance $N^{\ast }(2080)$ (spin-parity $J^P=3/2^{-}$), which has significant coupling to $K\Lambda (1520)$ channel. We show that the inclusion of the nucleon resonance $N^{\ast }(2080)$ leads to a fairly good description of the low energy experimental total cross section data of ${\pi }^{-}p\to K^0\Lambda (1520)$ reaction. From fitting to the experimental data, we get the $N^{\ast }(2080)N\pi$ coupling constant $g_{N^{\ast }(2080)N\pi }=0.14\pm 0.04$. By using this value and with the assumption that the excitation of $N^{\ast }(2080)$ is due to the ${\pi }^0$-meson exchanges, we calculate the total and differential cross sections of $pp\to p{K}^{+}\Lambda (1520)$ reaction. We also demonstrate that the invariant mass distribution and the Dalitz Plot provide direct information of the $\Lambda (1520)$ production, which can be tested by future experiments.

Comments: 9 pages, 7 figures