We present a new measurement of the e+e-→J/ψcc̄ cross section where the cc̄ pair can fragment either into charmed hadrons or a charmonium state. In the former case the J/ψ and a charmed hadron are reconstructed, while the latter process is measured using the recoil mass technique, which allows the identification of two-body final states without reconstruction of one of the charmonia. The measured e+e-→J/ψcc̄ cross section is (0.74±0.08+0.09-0.08)pb, and the e+e-→J/ψXnon- cc̄ cross section is (0.43±0.09±0.09)pb. We note that the measured cross sections are obtained from a data sample with the multiplicity of charged tracks in the event larger than 4; corrections for the effect of this requirement are not performed as this cannot be done in a model-independent way. The analysis is based on a data sample with an integrated luminosity of 673fb-1 recorded near the Υ(4S) resonance with the Belle detector at the KEKB e+e- asymmetric-energy collider.
|ジャーナル||Physical Review D - Particles, Fields, Gravitation and Cosmology|
|出版ステータス||Published - 2009 4月 1|
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