Doubly charmed pentaquarks

Abstract

The LHCb collaboration, using its full data set from runs 1 and 2, announced in 2019 a surprising update of the hidden-charm pentaquark states ${P}_{c}(4380{)}^{+}$ and ${P}_{c}(4450{)}^{+}$, observed in 2015. A new state, ${P}_{c}(4312{)}^{+}$, was clearly seen at lower energies; furthermore, the original ${P}_{c}(4450)$ resonance was resolved into two individual states, named the ${P}_{c}(4440{)}^{+}$ and the ${P}_{c}(4457{)}^{+}$. Motivated by the fact that these new hidden-charm pentaquark states were successfully predicted by our chiral quark model, we extend herein such study to the doubly charmed sector. The analyzed total spin and parity quantum numbers are ${J}^{P}={\frac{1}{2}}^{\ensuremath{-}}$, ${\frac{3}{2}}^{\ensuremath{-}}$ and ${\frac{5}{2}}^{\ensuremath{-}}$, in the $I=\frac{1}{2}$ and $\frac{3}{2}$ isospin channels. We find several possible narrow baryon-meson resonances (theoretical masses in parenthesis): $I{J}^{P}=\frac{1}{2}{\frac{1}{2}}^{\ensuremath{-}}$ ${\mathrm{\ensuremath{\Sigma}}}_{c}D(4356)$, $\frac{1}{2}{\frac{3}{2}}^{\ensuremath{-}}$ ${\mathrm{\ensuremath{\Sigma}}}_{c}^{*}D(4449)$, $\frac{3}{2}{\frac{1}{2}}^{\ensuremath{-}}$ ${\mathrm{\ensuremath{\Sigma}}}_{c}D(4431)$, $\frac{3}{2}{\frac{1}{2}}^{\ensuremath{-}}$ ${\mathrm{\ensuremath{\Sigma}}}_{c}D(4446)$, $\frac{3}{2}{\frac{3}{2}}^{\ensuremath{-}}$ ${\mathrm{\ensuremath{\Sigma}}}_{c}{D}^{*}(4514)$ and $\frac{3}{2}{\frac{5}{2}}^{\ensuremath{-}}$ ${\mathrm{\ensuremath{\Xi}}}_{cc}^{*}\ensuremath{\rho}(4461)$ whose widths are 4.8, 8.0, 2.6, 2.2, 4.0 and 3.0 MeV, respectively. Moreover, one shallow bound state is found, too, with quantum numbers $I{J}^{P}=\frac{1}{2}{\frac{3}{2}}^{\ensuremath{-}}$ ${\mathrm{\ensuremath{\Xi}}}_{cc}^{*}\ensuremath{\pi}(3757)$. These doubly charmed pentaquark states are expected to be identified in future experiments.

Topics & Concepts