Top quark forward-backward asymmetry in the little Higgs model  

作　　者：郭星导 张印杰 赵树民 冯太傅 袁煦浩 李学潜 

机构地区：[1]Department of Physics and Technology, Hebei University [2]Center for High Energy Physics, Department of Engineering Physics, Tsinghua University [3]Department of Physics, Nankai University

出　　处：《Chinese Physics C》2014年第11期16-21,共6页中国物理C（英文版）

基　　金：Supported by National Natural Science Foundation of China(10975027,11275036,11047002);Natural Science Foundation of Hebei Province(A2013201277,A2011201118);Natural Science Fund of Hebei University(2011JQ05,2007113);open project of State Key Laboratory of Mathematics-Mechanization(Y3KF311CJ1);Natural Science Fund of Hebei University(2011JQ05,2012-242)

摘　　要：A sizable difference in top quark pair forward backward asymmetry （AFB） is observed at Tevatron. The discrepancy triggers many new physics beyond the standard model （SM） and then constrains the parameter spaces in them. In this article we calculate the AFB of the top-pair production at Tevatron up to next to leading order （NLO） in the little Higgs model （LHM）. We find that the contribution of ZH can be large enough to make up the gap between SM prediction and experimental data. Then, the parameter space for the couplings between ZH and quarks are constrained. Thus, this model can fulfill the experimental data, both in AFB and in cross section.A sizable difference in top quark pair forward backward asymmetry （AFB） is observed at Tevatron. The discrepancy triggers many new physics beyond the standard model （SM） and then constrains the parameter spaces in them. In this article we calculate the AFB of the top-pair production at Tevatron up to next to leading order （NLO） in the little Higgs model （LHM）. We find that the contribution of ZH can be large enough to make up the gap between SM prediction and experimental data. Then, the parameter space for the couplings between ZH and quarks are constrained. Thus, this model can fulfill the experimental data, both in AFB and in cross section.

关 键 词：forward-backward asymmetry little Higgs model one-loop diagram Feynman amplitude 

分 类 号：O572.33[理学—粒子物理与原子核物理]