Abstract
Using a sample of 158×106 Υ(2S) events collected with the Belle detector, we search for the first time for double-charmonium decays of the P-wave spin-triplet bottomonium states (Υ(2S) →γχ bJ, χ bJ→J/ψJ/ψ, J/ψψ ′, ψ ′ψ ′ for J=0, 1, and 2). No significant χ bJ signal is observed in the double-charmonium mass spectra, and we obtain the following upper limits: B(χ bJ→J/ψJ/ψ)<7.1×10 -5, 2.7×10 -5, 4.5×10 -5, B(χ bJ→ J/ψψ ′)<1.2×10 -4, 1.7×10 -5, 4.9×10 -5, B(χ bJ→ψ ′ψ ′)<3. 1×10 -5, 6.2×10 -5, 1.6×10 -5 for J=0, 1, and 2, respectively, at the 90% confidence level. These limits are significantly lower than the central values (with uncertainties of 50% to 70%) predicted using the light cone formalism but are consistent with calculations using the nonrelativistic QCD (NRQCD) factorization approach.
Original language | English |
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Article number | 071102 |
Journal | Physical Review D - Particles, Fields, Gravitation and Cosmology |
Volume | 85 |
Issue number | 7 |
DOIs | |
State | Published - 18 Apr 2012 |