Strangeness plus-one ($S=+1$) resonance-state P+*₀ via $K^+n→ K*0p$

In our current study, we delve into the peak-like structure observed during the reaction process of K⁺n→ K⁰p at approximately √s~2.5 GeV. Our focus centers on exploring the potential $S=+1$ resonance P+*₀≡ P^*₀ as an excited state within the extended vector-meson and baryon ($VB$) antidecuplet. To achieve this aim, we employ the effective Lagrangian method in conjunction with the $(u,t)$-channel Regge approach, operating within the tree-level Born approximation. We thoroughly examine various spin-parity quantum numbers for the resonance, resulting in a compelling description of the data, where MP^*₀≈2.5 GeV and ΓP^*₀≈100 MeV. Furthermore, we propose an experimental technique to amplify the signal-to-noise ratio ($S/N$) for accurately measuring the resonance. Notably, our findings reveal that background interference diminishes significantly within the K^* forward-scattering region in the center-of-mass frame when the K^* is perpendicularly polarized to the reaction plane. Additionally, we explore the recoil-proton spin asymmetry to definitively determine the spin and parity of the resonance. This study stands to serve as a valuable reference for designing experimental setups aimed at investigating and comprehending exotic phenomena in QCD. Specifically, our insights will inform future J-PARC experiments, particularly those employing higher kaon beam energies.