Zhang Jia Jun, Li Chong Sheng, Gao Jun, Zhang Hao, Li Zhao, Yuan C-P, Yuan Tzu-Chiang
Department of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871, China.
Phys Rev Lett. 2009 Feb 20;102(7):072001. doi: 10.1103/PhysRevLett.102.072001.
D0 and CDF collaborations at the Fermilab Tevatron have searched for nonstandard-model single top-quark production and have set upper limits on the anomalous top-quark flavor-changing neutral-current (FCNC) couplings kappatcg/Lambda and kappatug/Lambda using the measurement of the total cross section calculated at the next-to-leading order (NLO) in QCD. In this Letter, we report on the effect of anomalous FCNC couplings to various decay branching ratios of the top quark, calculated at the NLO. This result is not only mandatory for a consistent treatment of both the top-quark production and decay via FCNC couplings by D0 and CDF at the Tevatron, but is also important for the study of ATLAS and CMS sensitivity to these anomalous couplings at the CERN LHC.
费米实验室万亿电子伏特加速器（Tevatron）的D0和CDF合作组已对非标准模型单顶夸克产生进行了搜寻，并利用在量子色动力学（QCD）次领头阶（NLO）计算的总截面测量，对反常顶夸克味改变中性流（FCNC）耦合κtcg/Λ和κtug/Λ设置了上限。在本信中，我们报告了在NLO下计算的反常FCNC耦合对顶夸克各种衰变分支比的影响。该结果不仅对于Tevatron的D0和CDF通过FCNC耦合对顶夸克产生和衰变进行一致处理是必不可少的，而且对于研究欧洲核子研究中心（CERN）大型强子对撞机（LHC）上ATLAS和CMS对这些反常耦合的灵敏度也很重要。
