Probing top-quark couplings indirectly at Higgs factories
Probing top-quark couplings indirectly at Higgs factories
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DOI：
10.1088/1674-1137/42/12/123107
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发表时间：
2018-09
影响因子：
3.6
通讯作者：
G. Durieux;Jiayin 嘉荫 Gu 顾;E. Vryonidou;Cen 岑 Zhang 张
中科院分区：
文献类型：
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作者：
G. Durieux;Jiayin 嘉荫 Gu 顾;E. Vryonidou;Cen 岑 Zhang 张
我们进行了一个全球有效场论分析，以评估希格斯耦合，三重规范玻色子耦合和顶夸克耦合的组合精度，在未来的圆形e+e−对撞机，重点是运行低于tt的生产阈值。在顶夸克部门的偏差进入作为一个循环的修正一贯考虑到希格斯和diboson过程。我们发现，未来的轻子对撞机运行在低于tt '产生阈值的质心能量下，仍然可以通过测量虚顶夸克效应来提供关于顶夸克耦合的有用信息。通过速率和差分测量，可以实现的间接个体灵敏度优于高光度LHC。然而，提取的顶夸克和希格斯耦合之间的强相关性也存在，并导致弱得多的顶夸克耦合的全局约束。这意味着，直接探测高于tt ′产生阈值的顶夸克耦合也有助于确定希格斯玻色子和三规范玻色子耦合。此外，我们发现，在e+e−→tt <$h产生阈值以下，顶夸克汤川耦合可以通过其对所有Higgs产生和衰变通道的环修正来确定。ggh耦合的简并可以解决，甚至一个全局极限也可以与线性对撞机在阈值以上的前景竞争。这为在轻子对撞机上间接确定顶夸克汤川耦合提供了一种额外的手段。
We perform a global effective-field-theory analysis to assess the combined precision of Higgs couplings, triple gauge-boson couplings, and top-quark couplings, at future circular e+e− colliders, with a focus on runs below the tt¯ production threshold. Deviations in the top-quark sector entering as one-loop corrections are consistently taken into account in the Higgs and diboson processes. We find that future lepton colliders running at center-of-mass energies below the tt¯ production threshold can still provide useful information on top-quark couplings, by measuring virtual top-quark effects. With rate and differential measurements, the indirect individual sensitivity achievable is better than at the high-luminosity LHC. However, strong correlations between the extracted top-quark and Higgs couplings are also present and lead to much weaker global constraints on top-quark couplings. This implies that a direct probe of top-quark couplings above the tt¯ production threshold is also helpful for the determination of Higgs and triple-gauge-boson couplings. In addition, we find that below the e+e−→tt¯h production threshold, the top-quark Yukawa coupling can be determined by its loop corrections to all Higgs production and decay channels. Degeneracy with the ggh coupling can be resolved, and even a global limit is competitive with the prospects of a linear collider above the threshold. This provides an additional means of determining the top-quark Yukawa coupling indirectly at lepton colliders.