Top FCNC induced by a Z′ boson
Top FCNC induced by a Z′ boson
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DOI：
10.1103/physrevd.101.055015
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发表时间：
2019-10
影响因子：
5
通讯作者：
Sungwoong Cho;P. Ko;Jungil Lee;Y. Omura;Chaehyun Yu
中科院分区：
文献类型：
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作者：
Sungwoong Cho;P. Ko;Jungil Lee;Y. Omura;Chaehyun Yu
我们考虑一个Z′玻色子只与上夸克和顶夸克耦合的Z′模型。对于一个简单的设置，我们可以考虑一个家族相关的U（1）′对称性，在这个对称性下，只有右手向上型夸克是带电的。对称性破缺后，右手夸克相互混合，在树的水平上可以产生由Z′玻色子介导的顶部变味中性流（FCNC）。我们在部分子水平上考虑了几个过程来探测顶FCNC，发现同号顶夸克对产生或三重顶夸克产生是最有能力测试顶FCNC的。我们还考虑了一些非FCNC过程来探测Z′玻色子，例如，在LHC的dijet生产。最后，我们在探测器水平进行数值分析，发现同号顶夸克对的生产提供了一个更严格的约束FCNC耦合比其他过程中的大多数参数空间。
We consider a Z′ model in which the Z′ boson couples only to up and top quarks. For a simple setup, one can consider a family-dependent U(1)′ symmetry, under which only right-handed up-type quarks are charged. After symmetry breaking, the right-handed quarks mix with each other, and top flavor-changing neutral currents (FCNCs) mediated by the Z′ boson can be generated at tree level. We take into account several processes at the parton level to probe the top FCNCs and find that the same-sign top quark pair production or the triple top quark production is the most capable of testing the top FCNCs. We also consider a few non-FCNC processes to probe the Z′ boson, for example, dijet production at the LHC. Finally, we perform numerical analysis at detector level and find that the same-sign top quark pair production provides a much more stringent bound on the FCNC coupling than the other processes in most of the parameter space.