Strong Decay of $P_c(4380)$ Pentaquark in a Molecular Picture.

There are different assumptions on the substructure of the pentaquarks $P_c(4380)$ and $P_c(4450)$, newly founded in $J/\psi N $ invariant mass by the LHCb collaboration, giving consistent mass results with the experimental observations. The experimental data and recent theoretical studies on their mass allow us to interpret them as spin-3/2 negative-parity and spin-5/2 positive-parity pentaquarks, respectively. There may exist opposite-parity states corresponding to these particles, as well. Despite a lot of studies, however, the nature and organization of these pentaquarks in terms of quarks and gluons are not clear. To this end we need more theoretical investigations on other physical properties of these states. In this accordance, we study a strong and dominant decay of the $P_c(4380)$ to $J/\psi$ and $N$ in the framework of three point QCD sum rule method. An interpolating current in a molecular form is applied to calculate six strong coupling form factors defining the transitions of the positive and negative parity spin-3/2 pentaquark states. The results of the coupling constants are used in the calculation of the decay widths of these transitions. The obtained result for the decay with of the negative parity state is compatible with the experimental observation. Our prediction for the width of the opposite-parity state's transition may help experimentalists in the search for the possible positive parity spin-3/2 pentaquark of $\bar{c}cduu$.