LHCb $P_c^+$ Resonances as Molecular States

Recent experiments at the LHCb detector have once again raised the possibility that quark bags may exist containing more than three quarks. Specifically the LHCb collaboration points to evidence for hadronic resonances decaying into J/$\psi$ and proton: the $P_c(4450)^+$ and $P_C(4380)^+$. Here we put forth a case that a reasonable description of these states is possible as molecular resonances of a $p$ and a J/$\psi$. Our model seems to accommodate the observed states and their measured widths, both the lower lying, broader, negative parity state and the higher lying, narrow positive parity state. If these resonances do indeed exist one might envision a rich spectroscopy of such pentaquark states waiting to be discovered, though this would deepen the mystery of their absence in earlier hadron spectroscopy. Perhaps the presence of the heavy charmed quarks, as well as the lighter u,d and s quarks, is the determining factor.