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标题：Electroweak penguins in isospin-violating Bs decays
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作者：D. Scherer ; L. HOFER ; L. Vernazza 等
期刊名称：PoS - Proceedings of Science
印刷版ISSN：1824-8039
出版年度：2010
卷号：2010
出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：The 2.5s discrepancy between theory and experiment observed in the difference DACP = ACP(B− →p 0K−)−ACP(¯B0 →p+K−) can be explained by a new electroweak (EW) penguin amplitude. Motivated by this result, we have analyzed the purely isospin-violating decays ¯B s →fp 0 and ¯Bs →fr 0, which are dominated by EW penguins. Our results extend the analysis in [1] and have recently been published in [2]. Here we give a brief overview of the outcome. We show that in presence of a new EW penguin amplitude the two Bs branching ratios can be enhanced by an order of magnitude without violating any constraints from other hadronic B decays. This makes them very interesting modes for LHCb and Super B factories. We perform both a model-independent analysis and a study within realistic New Physics (NP) models such as a modified-Z0-penguin scenario, a model with an additional Z′ boson and the MSSM, including a fit to B → pK data and the relevant experimental constraints throughout. In the model-independent case we study effective b → s ¯ qq couplings and distinguish between several possible chirality structures. Constraints arise from a large number of hadronic B decays such as B → pK(∗) ,rK(∗) ,fK(∗) etc. The preferred fit regions are rather large and allow for order-of-magnitude enhancements (see plots). In concrete models the new amplitude can often be correlated with other flavour phenomena, such as semileptonic B decays and Bs-¯Bs mixing, which set stringent constraints on the enhancement of the two Bs decays. In particular we find that, contrary to claims in the literature, EW penguins in the MSSM can reduce the discrepancy in DACP only marginally. Consequently no visible enhancement of ¯Bs →fp 0 ,fr 0 is expected for this model. As byproducts of our work we update the Standard Model (SM) predictions to BR(¯Bs→fp 0)=1.6+1.1 −0.3 ·10−7 and BR(¯Bs→fr 0)=4.4+2.7 −0.7 ·10−7 and performa state-of-the-art analysis of B→pK amplitudes in QCD factorisation (QCDF).