Flavor-violation tests of the warped/composite standard model in the two-site approach
Flavor-violation tests of the warped/composite standard model in the two-site approach
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DOI：
10.1103/physrevd.79.056006
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发表时间：
2009-03-01
影响因子：
5
通讯作者：
Zhu, Lijun
中科院分区：
文献类型：
--
作者：
Agashe, Kaustubh;Azatov, Aleksandr;Zhu, Lijun
我们在标准模型（SM）的纯4D、双场点有效场论描述中研究了夸克扇区的味违反，以及来自扭曲额外维度的第一个卡鲁扎-克莱因激发。翘曲的5D框架可以提供对SM的普朗克弱和风味层次的解决方案。它也与SM的部分复合性有关（通过AdS/CFT对应）。我们专注于占主导地位的贡献，在两个网站的模型，我们认为提供最强的约束，从味道违反，即，BR（B -> s伽玛），在两个网站的模型中的贡献发生在树和循环级别，分别。特别是，我们证明了这两个观测值之间存在一个“张力”，在这个意义上，他们有相反的依赖复合网站汤川耦合，使其难以解耦的味道违反使用此参数的影响。我们选择的复合网站QCD耦合的大小的基础上的关系的两个网站模型的5D模型（解决普朗克弱层次），其中我们匹配的5D QCD耦合的4D耦合在回路水平，并假设可以忽略不计的树级膜局域动力学项。我们估计，一个更大的尺寸的5D规范耦合的5D微扰性的要求受到限制。我们发现，类似于O（5）TeV的质量标度的新粒子在两个网站模型，然后可以符合两个观测。我们还比较了我们在两个网站模型的分析，在5D模型中，包括一个膜本地化和散装希格斯粒子的情况下，在2K（K）。
We study flavor violation in the quark sector in a purely 4D, two-site effective field theory description of the standard model (SM) and just their first Kaluza-Klein excitations from a warped extra dimension. The warped 5D framework can provide solutions to both the Planck-weak and flavor hierarchies of the SM. It is also related (via the AdS/CFT correspondence) to partial compositeness of the SM. We focus on the dominant contributions in the two-site model to two observables which we argue provide the strongest constraints from flavor violation, namely, epsilon(K) and BR(b -> s gamma), where contributions in the two-site model occur at tree and loop-level, respectively. In particular, we demonstrate that a "tension" exists between these two observables in the sense that they have opposite dependence on composite site Yukawa couplings, making it difficult to decouple flavor-violating effects using this parameter. We choose the size of the composite site QCD coupling based on the relation of the two-site model to the 5D model (addressing the Planck-weak hierarchy), where we match the 5D QCD coupling to the 4D coupling at the loop-level and assuming negligible tree-level brane-localized kinetic terms. We estimate that a larger size of the 5D gauge coupling is constrained by the requirement of 5D perturbativity. We find that similar to O(5) TeV mass scale for the new particles in the two-site model can then be consistent with both observables. We also compare our analysis of epsilon(K) in the two-site model to that in 5D models, including both the cases of a brane-localized and bulk Higgs.