γ Production at Fermilab Tevatron and LHC Energies
γ Production at Fermilab Tevatron and LHC Energies
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DOI：
10.1103/physrevlett.101.152001
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发表时间：
2008-10-10
影响因子：
8.6
通讯作者：
Tramontano, F.
中科院分区：
文献类型：
--
作者：
Artoisenet, P.;Campbell, J.;Tramontano, F.
我们在非相对论QCD框架下更新了直接γ（nS）强子产生的理论预言。我们表明，alpha（S）对色单态跃迁的次领先阶修正显着提高了高p（T）处的微分截面，并极大地影响了γ的极化。受次领先级产额和费米实验室Tevatron截面测量之间的剩余差距的启发，我们评估了α（5）（S）贡献的领先部分，即来自与三个轻部分子相关的Y（nS）的贡献。在α（5）（S）处的微分色单重态截面与数据基本一致，因此没有证据表明需要色八重态贡献。此外，我们发现，伽玛（nS）的偏振是纵向的。我们还提出了我们的预测伽玛（nS）的生产在LHC。
We update the theoretical predictions for direct gamma(nS) hadroproduction in the framework of nonrelativistic QCD. We show that the next-to-leading order corrections in alpha(S) to the color-singlet transition significantly raise the differential cross section at high p(T) and substantially affect the polarization of the gamma. Motivated by the remaining gap between the next-to-leading order yield and the cross-section measurements at the Fermilab Tevatron, we evaluate the leading part of the alpha(5)(S) contributions, namely, those coming from Y(nS) associated with three light partons. The differential color-singlet cross section at alpha(5)(S) is in substantial agreement with the data, so that there is no evidence for the need of color-octet contributions. Furthermore, we find that the polarization of the gamma(nS) is longitudinal. We also present our predictions for gamma(nS) production at the LHC.