ISSN - 03702693, Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 2002, vol. 540, p. 33-42
Measurement of Χc2 production in two-photon collisions
The production of the Χc2 charmonium state in two-photon collisions has been measured with the Belle detector at the KEKB e+e- collider. A clear signal for Χc2 → γ J / ψ, J / ψ → ℓ+ℓ- is observed in a 32.6 fb-1 data sample accumulated at center-of-mass energies near 10.6 GeV, and the product of its two-photon decay width and branching fraction is determined to be Λγγ (Xc2)Β(Xc2 → γ J / ψ)Β(J / ψ → ℓ+ℓ-) = 13.5 ±(stat.) ± 1.1(syst.) eV. © 2002 Elsevier Science B.V. All rights reserved.