Study ofX(3915)→J/ψωin two-photon collisions

J. P. Lees, V. Poireau, V. Tisserand, J. Garra Tico, E. Grauges, A. Palano, G. Eigen, B. Stugu, D. N. Brown, L. T. Kerth, Yu. G. Kolomensky, G. Lynch (+352 others)
2012 Physical Review D  
We study the process $\gamma \gamma \to J/\psi \omega$ using a data sample of 519.2 $fb^{-1}$ recorded by the BaBar detector at SLAC at the PEP-II asymmetric-energy $e^+ e^-$ collider at center-of-mass energies near the $\Upsilon(nS)$ ($n = 2,3,4$) resonances. We confirm the existence of the charmonium-like resonance X(3915) decaying to $J/\psi \omega$ with a significance of 7.6 standard deviations, including systematic uncertainties, and measure its mass $(3919.4 \pm 2.2 \pm 1.6) MeV/c^2$ and
more » ... 1.6) MeV/c^2$ and width $(13 \pm 6 \pm 3) MeV$, where the first uncertainty is statistical and the second systematic. A spin-parity analysis supports the assignment $J^P=0^+$ and therefore the identification of the signal as due to the $\chi_{c0}(2P)$ resonance. In this hypothesis we determine the product between the two-photon width and the final state branching fraction to be $(52 \pm 10 \pm 3) eV$
doi:10.1103/physrevd.86.072002 fatcat:nyn7wgvghfd7rp4gd5usw7mi7i