Abstract

The ${P}_{c}(4312)$, ${P}_{c}(4440)$, and ${P}_{c}(4457)$ observed by the LHCb collaboration are very likely to be $S$-wave ${\mathrm{\ensuremath{\Sigma}}}_{c}{\overline{D}}^{(*)}$ molecular candidates due to their near threshold character. In this work, we study the hidden-charm decay modes of these ${P}_{c}$ states, ${P}_{c}\ensuremath{\rightarrow}J/\ensuremath{\psi}p({\ensuremath{\eta}}_{c}p)$, using a quark interchange model. The decay mechanism for the ${P}_{c}\ensuremath{\rightarrow}J/\ensuremath{\psi}p({\ensuremath{\eta}}_{c}p)$ processes arises from the quark-quark interactions, where all parameters are determined by the mass spectra of mesons. We present our results in two scenarios. In scenario I, we perform the dynamical calculations and treat the ${P}_{c}$ states as pure ${\mathrm{\ensuremath{\Sigma}}}_{c}{\overline{D}}^{(*)}$ molecules. In scenario II, after considering the coupled channel effect between different flavor configurations ${\mathrm{\ensuremath{\Sigma}}}_{c}^{(*)}{\overline{D}}^{(*)}$, we calculate these partial decay widths again. The decay patterns in these two scenarios can help us to explore the molecular assignment and the inner flavor configurations for the ${P}_{c}$ states. In particular, the decay widths of $\mathrm{\ensuremath{\Gamma}}({P}_{c}(4312)\ensuremath{\rightarrow}{\ensuremath{\eta}}_{c}p)$ are comparable to the $J/\ensuremath{\psi}p$ decay widths in both of these two scenarios. Future experiments like LHCb may confirm the existence of the ${P}_{c}(4312)$ in the ${\ensuremath{\eta}}_{c}p$ channel.

Highlights

  • In 2015, the LHCb collaboration reported two pentaquark states Pcð4380Þ and Pcð4450Þ in the J=ψp invariant mass distribution of the decay Λ0b → J=ψpK− [1]

  • We study the hidden-charm decay modes of these Pc states, Pc → J=ψpðηcpÞ, using a quark interchange model

  • We further explore the influence of the coupled channel effect on the decay behaviors and perform the dynamical calculations on the partial decay widths for the hidden-charm molecular states both as the pure ΣðcÃÞDðÃÞ molecules and the admixtures of different flavor configurations

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Summary

INTRODUCTION

In 2015, the LHCb collaboration reported two pentaquark states Pcð4380Þ and Pcð4450Þ in the J=ψp invariant mass distribution of the decay Λ0b → J=ψpK− [1]. We extend the approach to give a quantitative estimate of the decay patterns of the Pc states These Pc states are probably hidden-charm molecules composed of a charmed baryon and a charmed meson, we have to find out whether they are pure ΣðcÃÞDðÃÞ molecular states or not. The mass splittings between different ΣðcÃÞDðÃÞ systems are comparable with the binding energy of the molecular states They may contribute to the same hidden-charm meson-baryon molecule as the coupled channel effect. We further explore the influence of the coupled channel effect on the decay behaviors and perform the dynamical calculations on the partial decay widths for the hidden-charm molecular states both as the pure ΣðcÃÞDðÃÞ molecules and the admixtures of different flavor configurations.

DECAY WIDTH
EFFECTIVE POTENTIAL
Pc STATES AS PURE ΣðcÃÞDðÃÞ MOLECULES
Heavy quark symmetry
Pc states as pure ΣðcÃÞDðÃÞ molecules
D Ã j2S1 2 i j4D1 2 i
Findings
SUMMARY
Full Text
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