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 $J^P={\frac{1}{2}}^{-}$, ${\frac{3}{2}}^{-}$ and ${\frac{5}{2}}^{-}$, in the $I=\frac{1}{2}$ and $\frac{3}{2}$ isospin channels. We find several possible narrow baryon-meson resonances (theoretical masses in parenthesis): $I{J}^P=\frac{1}{2}{\frac{1}{2}}^{-}$ ${\mathrm{\Sigma }}_{c}D(4356)$, $\frac{1}{2}{\frac{3}{2}}^{-}$ ${\mathrm{\Sigma }}_c^{*}D(4449)$, $\frac{3}{2}{\frac{1}{2}}^{-}$ ${\mathrm{\Sigma }}_{c}D(4431)$, $\frac{3}{2}{\frac{1}{2}}^{-}$ ${\mathrm{\Sigma }}_{c}D(4446)$, $\frac{3}{2}{\frac{3}{2}}^{-}$ ${\mathrm{\Sigma }}_c{D}^{*}(4514)$ and $\frac{3}{2}{\frac{5}{2}}^{-}$ ${\mathrm{\Xi }}_{cc}^{*}\rho (4461)$ 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 $I{J}^P=\frac{1}{2}{\frac{3}{2}}^{-}$ ${\mathrm{\Xi }}_{cc}^{*}\pi (3757)$. These doubly charmed pentaquark states are expected to be identified in future experiments.

• Received 12 March 2020
• Accepted 13 April 2020

DOI:https://doi.org/10.1103/PhysRevD.101.074030

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Published by the American Physical Society