Makiko Nagashima

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With U-spin symmetry, b → s and b → d penguin decays could be a subtle probe of CP violating new physics contributions. We show that, for B → P P (P stands for a pseudoscalar meson), the U-spin relation is expected to be violated for only one decay pair by assuming that new physics affects only b → s transition processes. We also very shortly discuss the(More)
B → φK * (¯ b → ¯ s) is three separate decays, one for each polarization of the final-state vector mesons (one longitudinal, two transverse). It is observed that the fraction of transverse decays, f T , and the fraction of longitudinal decays, f L , are roughly equal: f T /f L ≃ 1, in opposition to the naive expectation that f T ≪ f L. If one requires a(More)
We consider CP-violating effects in τ → Kππν τ , assuming that a charged Higgs boson provides a new amplitude that can interfere with the usual Standard Model amplitude. We consider four CP-odd observables – the regular rate asymmetry, two modified rate asymmetries and a triple-product asymmetry. The regular rate asymmetry is expected to be small because it(More)
We study the effect from a sequential fourth generation quark on penguin-dominated two-body nonleptonic B meson decays in the next-to-leading order perturbative QCD formalism. With an enhancement of the color-suppressed tree amplitude and possibility of a new CP phase in the electroweak penguin amplitude, we can account better for A(CP)(B(0)-->K+(More)
Within the standard model, a relation involving branching ratios and direct CP asymmetries holds for the B-decay pairs that are related by U-spin. The violation of this relation indicates new physics (NP). In this paper, we assume that the NP affects only the ∆S = 1 decays, and show that the NP operators are generally the same as those appearing in B → πK(More)
Direct CP violation in B0 --> K+ pi- decay has emerged at the -10% level, but the asymmetry in B+ --> K+ pi0 mode is consistent with zero. This difference points towards possible new physics in the electroweak penguin operator. We point out that a sequential fourth generation, with sizable V(t' s)* V(t' b) and near maximal phase, could be a natural cause.(More)
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