Searching for the $G(3900)$ via the $K^{-}p\to D_s^{-}{\Lambda }_c^{+}G(3900{)}^0$ reaction

Abstract

The nature of the $G(3900)$ structure, observed in $e^{+}{e}^{-}\to D\bar{D}$, remains unclear and may stem either from a genuine resonance or from charmonium interference and threshold effects. We therefore propose searching for the $G(3900)$ signal in the reaction $K^{-}p\to D_s^{-}{\Lambda }_c^{+}G(3900{)}^0$, where the interference effects present in $e^{+}{e}^{-}\to {\bar{D}}^{\ast }D$ are absent. We employ an effective Lagrangian approach, where the reaction proceeds via a central production mechanism dominated by $t$-channel $D^0$ and $D^{\ast 0}$ exchanges, based on the possible interpretation of $G(3900)$ as a $P$-wave ${\bar{D}}^{\ast }D$ molecular state, whose coupling to the ${\bar{D}}^{\ast }D$ channel is fixed from our previous fit to the $e^{+}{e}^{-}\to {\bar{D}}^{\ast }D$ data. The $\bar{K}N$ initial-state interaction, mediated by Pomeron and Reggeon exchanges, is also included and leads to a significant enhancement of the production cross section. If measured in future experiments, the predicted total cross sections and angular distributions can provide a promising probe of the nature of the $G(3900)$, and in particular of its possible genuine resonance nature.