Abstract
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 language | English |
|---|---|
| Article number | 114018 |
| Journal | Physical Review D - Particles, Fields, Gravitation and Cosmology |
| Volume | 76 |
| Issue number | 11 |
| DOIs | |
| Publication status | Published - 2007 Dec 27 |
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ASJC Scopus subject areas
- Physics and Astronomy(all)
- Nuclear and High Energy Physics
- Mathematical Physics
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Inclusive charm production in Υ(nS) decay. / Kang, Daekyoung; Kim, Taewon; Lee, Jungil; Yu, Chaehyun.
In: Physical Review D - Particles, Fields, Gravitation and Cosmology, Vol. 76, No. 11, 114018, 27.12.2007.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Inclusive charm production in Υ(nS) decay
AU - Kang, Daekyoung
AU - Kim, Taewon
AU - Lee, Jungil
AU - Yu, Chaehyun
PY - 2007/12/27
Y1 - 2007/12/27
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=37649008343&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=37649008343&partnerID=8YFLogxK
U2 - 10.1103/PhysRevD.76.114018
DO - 10.1103/PhysRevD.76.114018
M3 - Article
AN - SCOPUS:37649008343
VL - 76
JO - Physical review D: Particles and fields
JF - Physical review D: Particles and fields
SN - 0556-2821
IS - 11
M1 - 114018
ER -