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Title: Next-to-leading-order QCD correction to inclusive J/{psi}({Upsilon}) production in Z{sup 0} decay

Abstract

In this paper, we study the J/{psi}({Upsilon}) production in Z boson decay in a color-singlet model (CSM). We calculate the next-to-leading-order (NLO) QCD correction to Z{yields}quarkonium+QQ, the dominant contribution in the CSM, with the vector and axial-vector parts in the ZQQ vertex being treated separately. The results show that the vector and axial-vector parts have the same K factor (the ratio of the NLO result to the leading-order result) 1.13 with the renormalization scale {mu}=2m{sub c} and m{sub c}=1.5 GeV, and the K factor falls to 0.918 when applying the Brodsky, Lepage, and Mackenzie (BLM) renormalization scale scheme with obtained {mu}{sub BLM}=2.28 GeV and m{sub c}=1.5 GeV. By including the contributions from the next-dominant ones, the photon and gluon fragmentation processes, the branching ratio for Z{yields}J/{psi}{sub prompt}+X is (7.3-10.0)x10{sup -5} with the uncertainty consideration for the renormalization scale and charm quark mass. The results are about one-half of the central value of the experimental measurement 2.1x10{sup -4}. Furthermore, the J/{psi} energy distribution in our calculation cannot describe the experimental data. Therefore, even at QCD NLO, the contribution to Z{yields}J/{psi}{sub prompt}+X from the CSM cannot fully account for the experimental measurement. And there should be contributions from other mechanisms, such asmore » the color-octet (COM) contributions. We define R{sub cc}=({Gamma}(Z{yields}J/{psi}ccX)/{Gamma}(Z{yields}J/{psi}X)) and obtain R{sub cc}=0.84 for only the CSM contribution and R{sub cc}=0.49 for COM and CSM contributions together. Then the R{sub cc} measurement could be used to clarify the COM contributions.« less

Authors:
;  [1]
  1. Institute of High Energy Physics, Chinese Academy of Sciences, P.O. Box 918(4), Beijing, 100049, China, and Theoretical Physics Center for Science Facilities, CAS, Beijing, 100049 (China)
Publication Date:
OSTI Identifier:
21432959
Resource Type:
Journal Article
Journal Name:
Physical Review. D, Particles Fields
Additional Journal Information:
Journal Volume: 82; Journal Issue: 5; Other Information: DOI: 10.1103/PhysRevD.82.054006; (c) 2010 American Institute of Physics; Journal ID: ISSN 0556-2821
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; BRANCHING RATIO; COLOR MODEL; COMPUTERIZED SIMULATION; CORRECTIONS; ENERGY SPECTRA; FRAGMENTATION; GEV RANGE 01-10; GLUONS; J PSI-3097 MESONS; MASS; PARTICLE DECAY; PARTICLE PRODUCTION; PHOTONS; QUANTUM CHROMODYNAMICS; QUARKONIUM; QUARKS; RENORMALIZATION; Z NEUTRAL BOSONS; BOSONS; CHARMONIUM; COMPOSITE MODELS; DECAY; DIMENSIONLESS NUMBERS; ELEMENTARY PARTICLES; ENERGY RANGE; FERMIONS; FIELD THEORIES; GEV RANGE; HADRONS; INTERMEDIATE BOSONS; INTERMEDIATE VECTOR BOSONS; MASSLESS PARTICLES; MATHEMATICAL MODELS; MESONS; PARTICLE MODELS; QUANTUM FIELD THEORY; QUARK MODEL; SIMULATION; SPECTRA; VECTOR MESONS

Citation Formats

Li, Rong, and Wang, Jian-Xiong. Next-to-leading-order QCD correction to inclusive J/{psi}({Upsilon}) production in Z{sup 0} decay. United States: N. p., 2010. Web. doi:10.1103/PHYSREVD.82.054006.
Li, Rong, & Wang, Jian-Xiong. Next-to-leading-order QCD correction to inclusive J/{psi}({Upsilon}) production in Z{sup 0} decay. United States. https://doi.org/10.1103/PHYSREVD.82.054006
Li, Rong, and Wang, Jian-Xiong. Wed . "Next-to-leading-order QCD correction to inclusive J/{psi}({Upsilon}) production in Z{sup 0} decay". United States. https://doi.org/10.1103/PHYSREVD.82.054006.
@article{osti_21432959,
title = {Next-to-leading-order QCD correction to inclusive J/{psi}({Upsilon}) production in Z{sup 0} decay},
author = {Li, Rong and Wang, Jian-Xiong},
abstractNote = {In this paper, we study the J/{psi}({Upsilon}) production in Z boson decay in a color-singlet model (CSM). We calculate the next-to-leading-order (NLO) QCD correction to Z{yields}quarkonium+QQ, the dominant contribution in the CSM, with the vector and axial-vector parts in the ZQQ vertex being treated separately. The results show that the vector and axial-vector parts have the same K factor (the ratio of the NLO result to the leading-order result) 1.13 with the renormalization scale {mu}=2m{sub c} and m{sub c}=1.5 GeV, and the K factor falls to 0.918 when applying the Brodsky, Lepage, and Mackenzie (BLM) renormalization scale scheme with obtained {mu}{sub BLM}=2.28 GeV and m{sub c}=1.5 GeV. By including the contributions from the next-dominant ones, the photon and gluon fragmentation processes, the branching ratio for Z{yields}J/{psi}{sub prompt}+X is (7.3-10.0)x10{sup -5} with the uncertainty consideration for the renormalization scale and charm quark mass. The results are about one-half of the central value of the experimental measurement 2.1x10{sup -4}. Furthermore, the J/{psi} energy distribution in our calculation cannot describe the experimental data. Therefore, even at QCD NLO, the contribution to Z{yields}J/{psi}{sub prompt}+X from the CSM cannot fully account for the experimental measurement. And there should be contributions from other mechanisms, such as the color-octet (COM) contributions. We define R{sub cc}=({Gamma}(Z{yields}J/{psi}ccX)/{Gamma}(Z{yields}J/{psi}X)) and obtain R{sub cc}=0.84 for only the CSM contribution and R{sub cc}=0.49 for COM and CSM contributions together. Then the R{sub cc} measurement could be used to clarify the COM contributions.},
doi = {10.1103/PHYSREVD.82.054006},
url = {https://www.osti.gov/biblio/21432959}, journal = {Physical Review. D, Particles Fields},
issn = {0556-2821},
number = 5,
volume = 82,
place = {United States},
year = {2010},
month = {9}
}