Interpretations of the new LHCb $P_c(4337)^+$ pentaquark state

Abstract

Recently the LHCb collaboration has observed a new pentaquark state, the $P_c(4337)^+$. Owing to its proximity to the $\chi_{c0}(1S) p$, $\bar{D}^* \Lambda_c$, $\bar{D} \Sigma_c$ and $\bar{D} \Sigma_c^*$ thresholds, this new pentaquark might very well be a meson-baryon bound state. However its spin and parity have not been determined yet and none of the previous possibilities can be ruled out. We briefly explore a few of these options and the consequences they entail in the present manuscript: (i) the $P_c(4337)^+$ might be a $\chi_{c0}(1S) p$ bound state, (ii) the $P_c(4312)^+$ and $P_c(4337)^+$ might be $\bar{D}^* \Lambda_c$ and $\bar{D} \Sigma_c$ states close to threshold, respectively, where the Breit-Wigner mass might not correspond to the location of the poles, (iii) the locations of the $P_c(4312)^+$ and $P_c(4337)^+$ might be explained in terms of the $\bar{D}^* \Lambda_c$-$\bar{D} \Sigma_c$ and $\bar{D}^* \Lambda_c$-$\bar{D} \Sigma_c^*$ coupled channel dynamics. This last option, though not the most probable explanation, is still potentially compatible with the double peak solution of the $P_{cs}(4459)^0$ and with what we know of the $P_c(4312)^+$. As a byproduct of the previous explorations, we conjecture the existence of a series of anticharmed meson - antitriplet charmed baryon bound states and calculate their masses.