Abstract
The recently discovered $P_c(4380)^+$ and $P_c(4450)^+$ states at LHCb have masses close to the $\bar D\Sigma_c^*$ and $\bar D^*\Sigma_c$ thresholds, respectively, which suggest that they may have significant meson-baryon molecular components. We analyze these states in the framework of a constituent quark model which has been applied to a wide range of hadronic observables, being the model parameters, therefore, completely constrained. The $P_c(4380)^+$ and $P_c(4450)^+$ are studied as molecular states composed by charmed baryons and open charm mesons. Several bound states with the proper binding energy are found in the $\bar D\Sigma_c^*$ and $\bar D^*\Sigma_c$ channels. We discuss the possible assignments of these states from their decay widths. Moreover, two more states are predicted, associated with the $\bar D\Sigma_c$ and $\bar D^* \Sigma_c^*$ thresholds.
Highlights
The recently discovered Pc(4380)+ and Pc(4450)+ states at LHCb have masses close to the D Σ∗c and D ∗Σc thresholds, respectively, which suggest that they may have significant meson-baryon molecular components
The Pc(4380)+ and Pc(4450)+ are very close to the D Σ∗c and D ∗Σc thresholds, respectively
At present it is still unfeasible to analytically derive these properties from the QCD Lagrangian, we model the interaction by a phenomenological confinement and the one-gluon exchange potentials, the last one, following De Rujula [11], coming from the lagrangian
Summary
The recently discovered Pc(4380)+ and Pc(4450)+ states at LHCb have masses close to the D Σ∗c and D ∗Σc thresholds, respectively, which suggest that they may have significant meson-baryon molecular components. We analyze these states in the framework of a constituent quark model which has been applied to a wide range of hadronic observables, being the model parameters, completely constrained. The Pc(4380)+ and Pc(4450)+ are very close to the D Σ∗c and D ∗Σc thresholds, respectively This fact suggests that, if there exist a strong enough residual interaction between the two particles, a bound state or a resonance can be formed.
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