Penguin Pollution in B->pi pi

CP-violating asymmetries in the decay $B^0(t)\to \pi^+ \pi^-$ are a potentially rich source of information about both strong and weak phases. In a previous treatment by the present authors use was made of an assumption about the relative magnitude of tree and penguin amplitudes contributing to this process. This assumption involved an ambiguity in relating the tree amplitude to the amplitude for $B \to \pi \ell \nu$. It is shown here that one can avoid this assumption, which ...

We present the new and updated $BABAR$ measurements of CP-violation studies for many $b\to s $ penguin decay modes. We report the first observation of mixing-induced CP-violation in $B^0 \to \eta ^{'} K^0$ with a significance (including systematic uncertainties) of 5.5$\sigma$. We also present the first observation of the decay $B^0 \to \rho ^0 K^0$. Using the time-dependent Dalitz plot analysis of $B^0\to K^+K^- K^0$ decay, the CP-parameters $\mathcal A_{CP}$ and $\beta_{eff...

We present a new method for measuring the CP phase \alpha. It requires the measurement of the pure penguin decays Bd(t) -> K(*) Kbar(*) and B_s -> K(*) Kbar(*). The method is quite clean: we estimate the theoretical uncertainty to be at most 5%. By applying the method to several K(*) Kbar(*) final states, \alpha can be extracted with a fourfold ambiguity. An additional assumption reduces this ambiguity to twofold: {\alpha, \alpha + \pi}. Since no \pi0 detection is needed, thi...

We study the penguin pollution in the B^0 -> J/psi K_S decay up to leading power in 1/m_b and to next-to-leading order in \alpha_s, m_b being the b quark mass and \alpha_s the strong coupling constant. The deviation \Delta S_{J/psi K_S} of the mixing-induced CP asymmetry from sin(2\phi_1) and the direct CP asymmetry A_{J/psi K_S} are both found to be of O(10^{-3}) in a formalism that combines the QCD-improved factorization and perturbative QCD approaches.

We discuss the theoretical interpretation of the $B\to\pi K$ system in the light of new data. Using the branching ratio and direct CP asymmetry of $B^0_d\to\pi^-K^+$, the picture of the direct CP violation in $B_d^0\to\pi^+\pi^-$ could be clarified: we predict $A_{CP}^{dir}(B_d\to\pi^+\pi^-)=-0.24\pm0.04$, which favours the BaBar measurement, and extract $\gamma=(70.0^{+3.8}_{-4.3})^\circ$, in agreement with the Standard-Model fits of the unitarity triangle. All $B\to\pi K$ m...

Measurements of the time-dependent CP asymmetry in the decay $B^0_d (t) \to \pi^+ \pi^-$ and its charge conjugate by the BELLE and BABAR collaborations currently yield $C_{\pi \pi}^{+-} = -0.46 \pm 0.13$ and $S_{\pi \pi}^{+-} = -0.74 \pm 0.16$, characterizing the direct and mixing-induced CP asymmetries, respectively. We study the implication of these measurements on the CKM phenomenology taking into account the available information in the quark mixing sector. Our analysis l...

We present an {\it algebraic} isospin approach towards a more straightforward and model-independent determination of the weak phase $\alpha$ (or $\phi_2$) and QCD penguin pollution in $B\to \pi\pi$ decays. The world averages of current experimental data allow us to impose some useful constraints on the isospin parameters of $B\to \pi\pi$ transitions. We find that the magnitude of $\alpha$ (or $\phi_2$) extracted from the indirect CP violation in $\pi^+\pi^-$ mode is in agreem...

Full expressions of the $B^0_d \to \pi^+ \pi^-$ and $B^0_d \to \pi^0 \pi^0$ amplitudes, given in terms of matrix elements of operators of the effective weak Hamiltonian, are used to study the dependence of the relevant branching ratios on the different contributions. The uncertainty in the extraction of the weak phase $\alpha$ from the measurement of the time-dependent asymmetry in $B^0_d \to \pi^+ \pi^-$ decays is also analyzed. We find that, among several effects which may ...

I discuss about a possibility of large electroweak penguin contribution in B --> K pi. To satisfy several relations among the branching ratios, we need large electroweak penguin contribution. The magnitude is larger than the theoretical estimation in the SM so that it may be including some new physics effects.

We discuss about a possibility of large electro-weak penguin contribution in B -> K pi from recent experimental data. The several relations among the branching ratios which realize when the contributions from tree type and electro-weak penguin are small compared with the gluon penguin and can be treated as the expansion parameters do not satisfy the data. The difference comes from the r^2 terms which is the square of the ratio with the gluon penguin and the main contribution ...