Kaluza–Klein fields characterizing, from a four-dimensional viewpoint, the presence of compact universal extra dimensions would alter low-energy observables through effects determined by some compactification scale, [Formula: see text], since the one-loop level, thus being particularly relevant for physical phenomena forbidden at tree level by the Standard Model. This paper explores, for the case of one universal extra dimension, such new-physics contributions to Higgs decays [Formula: see text], into pairs of quarks with different flavors, a sort of decay process which, in the Standard Model, strictly occurs at the loop level. Finite results, decoupling as [Formula: see text], are calculated. Approximate short expressions, valid for large compactification scales, are provided. We estimate that Kaluza–Klein contributions lie below predictions from the Standard Model, being about 2 to 3 orders of magnitude smaller for compactification scales within [Formula: see text].

中文翻译：

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夸克变味希格斯从一个普遍的额外维度衰变

Kaluza-Klein 场从四维的角度表征紧凑的通用额外维度的存在将通过由某种紧缩尺度确定的影响来改变低能可观测量，[公式：见文本]，因为单环水平，因此是与标准模型在树级别禁止的物理现象特别相关。本文探讨了对于一个普遍的额外维度的情况，这种新物理对希格斯的贡献衰变[公式：见正文]，成对具有不同风味的夸克，这是一种在标准模型中严格发生的衰变过程在循环级别。计算有限结果，解耦为 [公式：见文本]。提供了适用于大压缩比例的近似短表达式。