Observation of a charmonium-like enhancement in the gamma gamma --> omega J/psi process

TL;DR

This paper reports the observation of a new charmonium-like resonance in gamma gamma collisions producing omega J/psi, indicating potential new states in the 3.9 GeV region.

Contribution

First observation of a charmonium-like enhancement in gamma gamma --> omega J/psi, providing evidence for possible new exotic states in this mass region.

Findings

Observed a resonance at 3915 MeV/c^2

Measured width of the resonance as 17 MeV

Resonance may relate to previously reported states

Abstract

We report the results of a search for a charmonium-like state produced in the process gamma gamma --> omega J/psi in the 3.9-4.2 GeV/c^2 mass region. We observe a significant enhancement, which is well-described by a resonant shape with mass M = (3915 +/- 3 +/- 2) MeV/c^2 and total width Gamma = (17 +/- 10 +/- 3) MeV. This enhancement may be related to one or more of the three charmonium-like states so far reported in the 3.90-3.95 GeV/c^2 mass region.