Exotic vector charmonium and its leptonic decay width

Abstract

We propose a novel type of interpolating field operators, which manifests the\nhybrid-like configuration that the charm quark-antiquark pair recoils against\ngluonic degrees of freedom. A heavy vector charmonium-like state with a mass of\n$4.33(2)\\,{\\rm GeV}$ is disentangled from the conventional charmonium states in\nthe quenched approximation. This state has affinity for the hybrid-like\noperators but couples less to the relevant quark bilinear operator. We also try\nto extract its leptonic decay constant and give a tentative upper limit that it\nis less than one tenth of that of $J/\\psi$, which corresponds to a leptonic\ndecay width about dozens of eV. The connection of this state with $X(4260)$ is\nalso discussed.\n