Role of $K_0^{\ast }(700)$ exchange in the $p\bar{p}\to \Lambda \bar{\Lambda }$ reaction

Abstract

Based on the effective Lagrangian approach, we investigate the $p\bar{p}\to \Lambda \bar{\Lambda }$ reaction. Within this framework, we provide a dynamical explanation by analyzing its total and differential cross sections, as well as the polarization of the produced $\Lambda$ hyperon. Incorporating the $t$-channel exchange of the scalar $K_0^{\ast }(700)$ and pseudoscalar $K$ mesons, complemented by an $s$-channel contribution from the vector excited state, we can reproduce the current experimental data fairly well in a wide energy region. Compared to the conventional $K$ and $K^{\ast }(892)$ mesons exchange, the $K_0^{\ast }(700)$ meson exchange plays a more essential role in simultaneously capturing the observed features of the total and differential cross sections. The introduction of the vector $s$-channel resonance improves the description of the spin observables. This work gives a perspective to inspect the role of $K_0^{\ast }(700)$ and serves as a test to search for the resonances in the reaction $p\bar{p}\to \Lambda \bar{\Lambda }$ at threshold.

Comments: 11 pages, 5 figures