相关论文: Possibility of Large EW Penguin contribution

We calculate the important next-to-leading-order contributions to the B -> pi K, pi pi decays from the vertex corrections, the quark loops, and the magnetic penguins in the perturbative QCD approach. It is found that the latter two reduce…

Recent experiments suggest that certain B -> pi K branching ratios are inconsistent with the standard model expectations. We show that a flavor-changing Z' provides a solution to the problem. Electroweak penguin amplitudes are enhanced by…

The recent observation of B_d -> pi^0 pi^0 at the B factories with a surprisingly large branching ratio represents a challenge for theory, and complements the amazingly small B_d -> pi^+ pi^- rate. We point out that all puzzling B -> pi pi…

Based on the most recent data in charmless B decays including the very recently reported large direct CP violations, it is shown that the weak phase gamma can well be extracted without two-fold ambiguity even only from two decay modes…

The 2.5 sigma discrepancy between theory and experiment observed in the difference A_CP(B^- --> pi^0 K^-)-A_CP(Bbar^0 --> pi^+ K^-) can be explained by a new electroweak penguin amplitude. Motivated by this result, we analyse the purely…

A general parametrization of the $B^+\to\pi^+ K^0$ and $B_d^0\to\pi^- K^+$ decay amplitudes is presented. It relies only on the isospin symmetry of strong interactions and the phase structure of the Standard Model and involves no…

In charmless nonleptonic B decays to \pi\pi or \rho\rho, the "color allowed" and "color suppressed" tree amplitudes can be studied in a systematic expansion in \alphas(mb) and \Lambda/mb. At leading order in this expansion their relative…

We investigate the $B\to a_1(1260)(b_1(1235))\pi(K)$ decays under the factorization scheme and find many discrepancies between theoretical predictions and the experimental data. In the tree dominated processes, large contributions from…

We perform a fit to the 2006 B -> pi K data and show that there is a disagreement with the standard model. That is, the B -> pi K puzzle is still present. In fact, it has gotten worse than in earlier years. Assuming that one new-physics…

We calculate the branching ratio of $B\to J/\Psi\pi^{0}$ with a mixed formalism that combines the QCD-improved factorization and the perturbative QCD approaches. The result is consistent with experimental data. The quite small penguin…

Although recent experimental results in b-->s penguin process seem to be roughly consistent with the standard model predictions, there may be still large possibilities of new physics hiding in this processes. Therefore, here we investigate…

We discuss implications of recent experimental data for B decays into two pseudoscalar mesons, with emphasis on those with $\eta$ and $\eta'$ in the final states. Applying a U-spin argument, we show that tree and penguin amplitudes, both in…

We report improved measurements of branching fractions for B -> K pi and B -> pi pi decays based on a data sample of 449 million B Bbar pairs collected at the Upsilon(4S) resonance with the Belle detector at the KEKB e^+e^- collider. We…

The present B -> pi K data is studied in the context of the standard model (SM) and with new physics (NP). We confirm that the SM has difficulties explaining the B -> pi K measurements. By adopting an effective-lagrangian parametrization of…

We report on recent progress in studying two aspects of $B$ physics, in which penguin amplitudes play an important role: (1) Bounds on penguin pollution in $B^0(t) \to \pi^+\pi^-$ constraining CKM parameters, and a lower bound on $B^0 \to…

We discuss a novel electromagnetic penguin contribution to the transverse helicity amplitudes in B decays to two vector mesons, which is enhanced by two powers of mB/Lambda relative to the standard penguin amplitudes. This leads to unique…

For about twenty years, $B\to\pi K$ decays are in the focus of $B$-decay studies. We show that a correlation between the CP asymmetries of $B^0_d\to\pi^0K_{\rm S}$ reveals a tension with the Standard Model. Should it be due to New Physics,…

Using the $SU(3)$ flavour symmetry of strong interactions, we propose strategies for extracting both the CKM-angle $\gamma$ and the $\bar b\to\bar uu\bar s$ tree-level amplitude $T'$. We present also an approximate approach using the…

The question of the relative size of tree and penguin amplitudes is analyzed using the data on B to pi pi, B^+ to pi^+ K^0, and B^+ to K^+ \bar{K}^0 decays. Our discussion involves an estimate of SU(3) breaking in the final…

In the past decade, electroweak penguin decays have provided a number of precision measurements, turning into one of the most competitive ways to search for New Physics that describe beyond the Standard Model phenomena. An overview of the…