Understanding close-lying exotic charmonia states within QCD sum rules

Abstract

Motivated by the experimental findings of some new exotic states decaying into channels like $J/\psi \varphi$, we investigate the formation of resonances/bound states in the $D_s^{\ast }{\bar{D}}_s^{\ast }$ system using QCD sum rules. To do this we start with a current of the type vector times vector and use spin projectors to separate the spin 0, 1 and 2 contributions to the correlation function. We find three states with isospin 0, nearly spin degenerate, with a mass around 4.1 GeV. We have also investigated the decay of these states to $J/\psi \varphi$ and provide the corresponding partial widths. Such information should be useful for experimental studies in future.

Comments: New calculations included on the widths of the states, published version