Reexamination of the role of the $\Delta ^{\ast}$ resonances in the $pp\rightarrow nK^{+}\Sigma ^{+}$ reaction

TL;DR

This paper investigates the role of $elta^*$ resonances in the $pp o nK^+eta^+$ reaction using an effective Lagrangian and isobar model, identifying key resonances influencing the process.

Contribution

It systematically analyzes the contributions of various $elta^*$ resonances and their interference effects in $Keta$ production near threshold energies.

Findings

A $P_{31}$ $elta^*$ state is favored by data.

The $P_{33}$ $elta^*(1920)$ has a small contribution.

Sub-threshold $elta^*(1620)$ or strong $neta$ final state interaction may contribute near threshold.

Abstract

In this work, the role of the $\Delta ^{\ast }$ resonances in the process of $pp\rightarrow nK^{+}\Sigma ^{+}$ are systematically investigated with the effective Lagrangian approach and the isobar model. We find that a $P_{31}$ state, either $\Delta ^{\ast }(1750)$ or $\Delta ^{\ast }(1910)$, is favored by the data while the $P_{33}$ state, namely $\Delta ^{\ast }(1920)$, has small contribution. Besides, either sub-threshold $S_{31}$ $\Delta ^{\ast }(1620)$ resonance or strong $n\Sigma $ final state interaction or both have possible contribution at near threshold region, depending on the measured cross sections. We demonstrate the invariant mass distributions and the Dalitz Plots in order to investigate whether it is possible to distinguish the controversial $K\Sigma $ production mechanism in these observables.