ISSN - 15507998, Physical Review D - Particles, Fields, Gravitation and Cosmology, 2013, vol. 87, p. -
Study of the near-threshold ω mass enhancement in doubly OZI-suppressed J/ψ→γω decays
© 2013 American Physical Society. A 2.25×108 J/ψ event sample accumulated with the BESIII detector is used to study the doubly Okubo-Zweig-Iizuka-suppressed decay modes J/ψ→γω, ω→π<sup>+</sup>π<sup>-</sup>π0, →K<sup>+</sup>K<sup>-</sup>. A strong deviation (>30σ) from three-body J/ψ→γω phase space is observed near the ω mass threshold that is consistent with a previous observation reported by the BESII experiment. A partial wave analysis with a tensor covariant amplitude that assumes that the enhancement is due to the presence of a resonance, the X(1810), is performed and confirms that the spin-parity of the X(1810) is 0 <sup>++</sup>. The mass and width of the X(1810) are determined to be M=1795±7(stat)-5+13(syst)±19(mod) MeV/c2 and Γ= 95±10(stat)-34+21(syst)±75(mod) MeV/c2, respectively, and the product branching fraction is measured to be B(J/ψ→γX(1810)) ×B(X(1810)→ω)=(2.00±0.08(stat)-1.00+0.45(syst)±1. 30(mod))×10<sup>-</sup>4. These results are consistent within errors with those of the BESII experiment.