Next-to-Leading-Order QCD corrections to $J/\psi (\upsilon) + \gamma$ production at the LHC
Next-to-Leading-Order QCD corrections to $J/\psi (\upsilon) + \gamma$ production at the LHC
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DOI：
10.1016/j.physletb.2008.12.050
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发表时间：
2008-11
影响因子：
4.4
通讯作者：
Rong Li;Jian-xiong Wang
中科院分区：
文献类型：
--
作者：
Rong Li;Jian-xiong Wang
In this work, we calculate the next-to-leading-order (NLO) QCD corrections to the process p+p{yields}J/{psi}+{gamma} via the color-singlet mechanism at the LHC. The results show that the partial cross section (p{sub t}{sup J/{psi}}>3 GeV and |y{sup J/{psi}}{sup ,{gamma}}|<3) is enhanced by a factor of about 2.0, and the differential cross section can be enhanced by two orders of magnitude in the large transverse momentum region of J/{psi}. Furthermore, the polarization of J/{psi} changes from transverse polarization at leading-order to longitudinal polarization at NLO. For the inclusive J/{psi} hadroproduction, it is known that the color-octet contributions are one order of magnitude larger than the color-singlet contribution, and the polarization distribution is dominated by the color-octet behavior at NLO. In contrast, for J/{psi}+{gamma} production the color-singlet contribution is of the same order as the color-octet contribution, and the polarization distribution arises from both the color-singlet and color-octet. Therefore, measurements of J/{psi} production associated with a direct photon at the hadron collider could be an important supplement to testify the theoretical framework treating with the heavy quarkonium. In addition, an NLO QCD correction to Y+{gamma} production at the LHC is also presented in this Letter.
In this work, we calculate the next-to-leading-order (NLO) QCD corrections to the process p+p{yields}J/{psi}+{gamma} via the color-singlet mechanism at the LHC. The results show that the partial cross section (p{sub t}{sup J/{psi}}>3 GeV and |y{sup J/{psi}}{sup ,{gamma}}|<3) is enhanced by a factor of about 2.0, and the differential cross section can be enhanced by two orders of magnitude in the large transverse momentum region of J/{psi}. Furthermore, the polarization of J/{psi} changes from transverse polarization at leading-order to longitudinal polarization at NLO. For the inclusive J/{psi} hadroproduction, it is known that the color-octet contributions are one order of magnitude larger than the color-singlet contribution, and the polarization distribution is dominated by the color-octet behavior at NLO. In contrast, for J/{psi}+{gamma} production the color-singlet contribution is of the same order as the color-octet contribution, and the polarization distribution arises from both the color-singlet and color-octet. Therefore, measurements of J/{psi} production associated with a direct photon at the hadron collider could be an important supplement to testify the theoretical framework treating with the heavy quarkonium. In addition, an NLO QCD correction to Y+{gamma} production at the LHC is also presented in this Letter.