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Role of the $N^*(2080)$ in $pp \to pK^+ Λ(1520)$ and $π^- p \to K^0 Λ(1520)$ reactions

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