Production of $K^* \Sigma$ and $D^* \Sigma_c$ in pion-induced reactions off the nucleon

Abstract

We investigate the mechanisms of strangeness production in the $\pi^- p \to K^{*0} \Sigma^0$ and $\pi^- p \to K^{*+} \Sigma^-$ reactions within a hybrid Regge framework in which effective Lagrangian vertices are combined with Reggeized exchanges. The nonresonant background consists of $t$-channel $K$- and $K^*$-Reggeon exchanges, $s$-channel nucleon and $\Delta$ exchanges, and $u$-channel $\Sigma$- and $\Lambda$-Reggeon exchanges, whose roles differ markedly between the two isospin channels. We additionally include several $N^*$ and $\Delta^*$ resonances in the $s$ channel and find that the $\Delta(2150)1/2^-$ resonance provides the dominant near-threshold contribution. The resulting total and differential cross sections and spin-density matrix elements (SDMEs) are in good agreement with the available data. Additional measurements near threshold ($W \lesssim$ 2.5 GeV) would be valuable for clarifying the role of $s$-channel baryon resonances. Within the same framework, with Regge trajectories and energy-scale parameters fixed by a QGSM-motivated prescription, we also predict the cross sections for the charm-production reactions $\pi^- p \to D^{*-} \Sigma_c^+$ and $\pi^- p \to D^{*0} \Sigma_c^0$. Their total cross sections are suppressed by approximately $4$--$5$ and $7$--$8$ orders of magnitude, respectively, compared with those of the corresponding strangeness-production reactions. These results may serve as useful guidance for future experiments at facilities such as J-PARC.