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arXiv 0907.5408hep-ph
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tan-beta增强超对称回路修正超出去耦极限的恢复

Resummation of tan-beta-enhanced supersymmetric loop corrections beyond the decoupling limit

Lars Hofer, Ulrich Nierste, Dominik Scherer

摘要:

本文研究了具有最小味破坏的最小超对称标准模型,其中tan β是大参数,超对称质量参数是任意值.我们推导出几个重申公式tan β增强环路校正,这是以前只知道在超对称质量远远高于电弱尺度的限制。首先研究底部汤川耦合的重正化公式的重正化方案依赖性,我们阐明了在超对称回路因子Delta_b中sbottom混合角的使用。作为一个新的功能,我们发现tan-β增强环诱导的味道变化中性电流(FCNC)耦合的胶子和中性子,这反过来又引起了新的影响,在重整化的Cabibbo-小林-Maskawa矩阵和FCNC过程中的B介子。对于色磁Wilson系数C_8,这些胶子-夸克环可以与已知的电荷-夸克贡献具有相同的大小。我们讨论了B_d-> phi K_S中混合诱导CP不对称性的唯象结果。我们进一步给出了B_s-> mu ^+ mu ^-和B_s-B_s棒混频在退耦极限以外的有效公式,并发现了影响B_s-B_s棒混频振幅相位的一个新贡献。我们的非线性tan-beta增强效应被转换为费曼规则,允许在自动计算中轻松实现。

英文摘要:

We study the Minimal Supersymmetric Standard Model with Minimal Flavour Violation for the case of a large parameter tanbeta and arbitrary values of the supersymmetric mass parameters. We derive several resummation formulae for tanbeta-enhanced loop corrections, which were previously only known in the limit of supersymmetric masses far above the electroweak scale. Studying first the renormalisation-scheme dependence of the resummation formula for the bottom Yukawa coupling, we clarify the use of the sbottom mixing angle in the supersymmetric loop factor Delta_b. As a new feature, we find tan-beta-enhanced loop-induced flavour-changing neutral current (FCNC) couplings of gluinos and neutralinos which in turn give rise to new effects in the renormalisation of the Cabibbo-Kobayashi-Maskawa matrix and in FCNC processes of B mesons. For the chromomagnetic Wilson coefficient C_8, these gluino-squark loops can be of the same size as the known chargino-squark contribution. We discuss the phenomenological consequences for the mixing-induced CP asymmetry in B_d -> phi K_S. We further quote formulae for B_s -> mu^+ mu^- and B_s-B_s-bar mixing valid beyond the decoupling limit and find a new contribution affecting the phase of the B_s-B_s-bar mixing amplitude. Our resummed tan-beta-enhanced effects are cast into Feynman rules permitting an easy implementation in automatic calculations.

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