Strange hidden-charm pentaquark poles from $B^{-}\to J/\ddot{I}ˆ\hat{I}›\bar{p}$

Abstract

Recent LHCb data for $B^{-}\to J/\ddot{I}ˆ\hat{I}›\bar{p}$ show a clear peak structure at the $\hat{I}{ž}_c\bar{D}$ threshold in the $J/\ddot{I}ˆ\hat{I}›$ invariant mass ($M_{J/\ddot{I}ˆ\hat{I}›}$) distribution. The LHCb's amplitude analysis identified the peak with the first hidden-charm pentaquark with strangeness $P_{\ddot{I}ˆs}^{\hat{I}}›(4338)$. We conduct a coupled-channel amplitude analysis of the LHCb data by simultaneously fitting the $M_{J/\ddot{I}ˆ\hat{I}›}$, $M_{J/\ddot{I}ˆ\bar{p}}$, $M_{\hat{I}›\bar{p}}$, and $\cos \hat{I}{¸}_{K^{\ast }}$ distributions. Rather than the Breit-Wigner fit employed in the LHCb analysis, we consider relevant threshold effects and a unitary $\hat{I}{ž}_c\bar{D}$-$\hat{I}{›}_c{\bar{D}}_s$ coupled-channel scattering amplitude from which $P_{\ddot{I}ˆs}^{\hat{I}}›$ poles are extracted for the first time. In our default fit, the $P_{\ddot{I}ˆs}^{\hat{I}}›(4338)$ pole is almost a $\hat{I}{ž}_c\bar{D}$ bound state at $(4338.2\pm 1.4)-(1.9\pm 0.5)i$ MeV. Our default model also fits a large fluctuation at the $\hat{I}{›}_c{\bar{D}}_s$ threshold, giving a $\hat{I}{›}_c{\bar{D}}_s$ virtual state, $P_{\ddot{I}ˆs}^{\hat{I}}›(4255)$, at $4254.7\pm 0.4$ MeV. We also found that the $P_{\ddot{I}ˆs}^{\hat{I}}›(4338)$ peak cannot solely be a kinematical effect, and a nearby pole is needed.

4 pages, 4 figures, Contribution to the Proceedings for 16th International Conference on Meson-Nucleon Physics and the Structure of the Nucleon (MENU 2023), October 15-20, 2023, Mainz, Germany