Inclusive charm production in {upsilon}(nS) decay

Journal Article · Sat Dec 01 04:00:00 EST 2007 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PHYSREVD.76.114018· OSTI ID:21023928

Kang, Daekyoung; Lee, Jungil ^[1]; Kim, Taewon; Yu, Chaehyun ^[1]

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1. Department of Physics, Korea University, Seoul 136-701 (Korea, Republic of)

Based on the nonrelativistic QCD (NRQCD) factorization formalism, we calculate the inclusive charm production rate in {upsilon}(nS) decay at leading order in the strong coupling constant {alpha}{sub s} and the relative velocity v of the b quark in the quarkonium rest frame. The branching fractions for {upsilon}(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 bb pair into {gamma}*{yields}cc. Most of the remaining branching fraction is from annihilation of the color-singlet bb pair decaying into ccgg. 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 ccgg 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.

• OSTI ID: 21023928
• Journal Information: Physical Review. D, Particles Fields, Journal Name: Physical Review. D, Particles Fields Journal Issue: 11 Vol. 76; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ANNIHILATION
B QUARKS
BRANCHING RATIO
C QUARKS
COLOR MODEL
DISTRIBUTION
FACTORIZATION
PARTICLE DECAY
PHOTONS
QUANTUM CHROMODYNAMICS
STRONG-COUPLING MODEL
UPSILON-10355 MESONS
UPSILON-10580 MESONS
UPSILON-9460 MESONS