Kaon-induced $\phi \Sigma$ production off the proton

Abstract

We investigate the reaction mechanism of $K^-p \to \phi\Sigma^0$ within a hybrid Regge approach based on effective Lagrangians. The nonresonant background includes Reggeized $t$-channel $K$ and $K^*$ exchanges, together with ground-state $\Sigma$ and nucleon exchanges in the $s$ and $u$ channels, respectively. To describe the structures observed at $3.0 \leqslant P_{\rm Lab} \leqslant 4.5$ GeV, we include the high-mass $\Sigma(2620)$ and $\Sigma(3000)$ resonances and examine the spin-parity assignments $J^P = 1/2^\pm$, $3/2^\pm$, and $5/2^\pm$. The $K^*$-Reggeon exchange dominates the forward-angle cross sections, whereas the smaller $K$-Reggeon contribution is important for the total cross section at low energies and for the spin-density matrix elements. The nonresonant background alone is not sufficient to reproduce the local structures in the total cross section or the differential cross sections at large $-t'$. Including the two resonances, particularly the $\Sigma(3000)$, substantially improves the agreement with the available data. The $J^P=5/2^-$ assignment for the $\Sigma(3000)$ provides a reasonable overall description, although the present data do not permit a definitive determination.