At BEACH 2014 I presented the paper Charmonium with an effective Morse molecular potential which has recently been published in the proceedings. In this paper I propose a completely new approach to charmonium spectroscopy. This approach allows the calculation of the parameters of the molecular potential, calculation of the radii of 5 S states, and information on the recently found charmonium-like states.
The paper has recently been published in the Journal of Nuclear and Particle Physics.
I propose that the two resonant states of the recently found pentaquark by LHCb with masses of 4380 MeV and 4450 MeV are two states of the hadronic molecule ccbar + proton with similar properties to those of the Karliner-Lipkin pentaquark. Applying the Morse molecular potential to this molecule an approximate minimum size is found for it. It is possible to suggest two S states. As it is well said in the article, it is a starting point for more elaborate models on this remarkable system. The fitting shows that the coupling constant is quite large, of the same order of that of J/Psi. This may indicate Physics Beyond the Standard Model because, according to the OZI rule of QCD, single gluon exchange is forbidden. And thus the important question is this one: What is the origin of such a large coupling?
I did the fitting exactly how I did for bottomonium and charmonium, but in the case of the pentaquark we are able to find out only two parameters. And because of the large Gamma of the 4380 MeV level the uncertainty is also large for the minimum size.
Tommaso Dorigo is right when he said in his blog that the Pentaquark had been predicted by Prof. Marek Karliner and that it is, actually, a hadronic molecule, and, thus, the five particles are not bound together forming a single cluster. Therefore, in this sense the true pentaquark was not found. To see the paper, please, click right here.