Inclusive charm production in Υ(nS) decay

Daekyoung Kang, Taewon Kim, Jungil Lee, Chaehyun Yu

Research output: Contribution to journalArticlepeer-review

22 Citations (Scopus)


Based on the nonrelativistic QCD (NRQCD) factorization formalism, we calculate the inclusive charm production rate in Υ(nS) decay at leading order in the strong coupling constant αs and the relative velocity v of the b quark in the quarkonium rest frame. The branching fractions for Υ(nS) to charm for n=1, 2, and 3 are all around 7%-9%. About 60% of the branching fraction into charm is from annihilation of the color-singlet bb̄ pair into γ*→cc̄. Most of the remaining branching fraction is from annihilation of the color-singlet bb̄ pair decaying into cc̄gg. We also compute the momentum distributions of the charm quark and charmed hadrons in the decays. The virtual-photon contribution to the charm-quark momentum distribution is concentrated at the end point while the cc̄gg contribution is broad. The momentum distributions for charmed hadrons are obtained by convolving the charm-quark momentum distribution with charm fragmentation functions. This makes the momentum distributions for charmed hadrons softer than that for the charm quark. This effect is particularly significant in the virtual-photon contribution.

Original languageEnglish
Article number114018
JournalPhysical Review D - Particles, Fields, Gravitation and Cosmology
Issue number11
Publication statusPublished - 2007 Dec 27

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Physics and Astronomy (miscellaneous)


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