# Study of X(3915) --> J/\psi \omega\ in two-photon collisions

Abstract : 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 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 ident ification 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 $(52 \pm 10 \pm 3) eV$
Document type :
Journal articles
Physical Review D, American Physical Society, 2012, 86, pp.072002. <10.1103/PhysRevD.86.072002>

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Contributor : Françoise Marechal <>
Submitted on : Thursday, July 12, 2012 - 2:21:55 PM
Last modification on : Monday, October 29, 2012 - 11:31:10 AM

### Citation

J. P. Lees, V. Poireau, V. Tisserand, D. Bernard, M. Verderi, et al.. Study of X(3915) --> J/\psi \omega\ in two-photon collisions. Physical Review D, American Physical Society, 2012, 86, pp.072002. <10.1103/PhysRevD.86.072002>. <in2p3-00717273>

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