Production of $K^{\ast }\Sigma$ and $D^{\ast }{\Sigma }_c$ in pion-induced reactions off the nucleon

Abstract

We investigate the mechanisms of strangeness production in the ${\pi }^{-}p\to K^{\ast 0}{\Sigma }^0$ and ${\pi }^{-}p\to K^{\ast +}{\Sigma }^{-}$ 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 $K^{\ast }$-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 $N^{\ast }$ and ${\Delta }^{\ast }$ 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 ${\pi }^{-}p\to D^{\ast -}{\Sigma }_c^{+}$ and ${\pi }^{-}p\to D^{\ast 0}{\Sigma }_c^0$. 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.

Comments: 14 pages, 12 figures