Narrow Results

New physics in the form of scalar/pseudoscalar operators cannot lower the semileptonic branching ratio Br(B → K μ⁺μ^-) below its standard model value. In addition, we show that the upper bound on the leptonic branching ratio Br(B_s → μ⁺μ^-) sets a strong constraint on the maximum value of Br(B → K μ⁺μ^-) in models with multiple Higgs doublets: with the current bound, Br(B → K μ⁺μ^-) cannot exceed the standard model prediction by more than 2.5%. The conclusions hold true even if the new physics couplings are complex. However, these constraints can be used to restrict new physics couplings only if the theoretical and experimental errors in Br(B → K μ⁺μ^-) are reduced to a few per cent. The constraints become relaxed in a general class of models with scalar/pesudoscalar operators.

In this paper, the non-leptonic three-body decays $B\to K^{\ast }(892)K\pi$, $\pi \pi$, $KK$ are studied by introducing two-meson distribution amplitude for the $K\pi$, $\pi \pi$ and $KK$ pairs in naive and QCD factorization (QCDF) approaches, such that the analysis is simplified into quasi-two body decays. By considering that the vector meson is being ejected in factorization, the resonant and non-resonant contributions are analyzed by using intermediate mesons in Breit–Wigner resonance formalism and the heavy meson chiral perturbation theory (HMChPT), respectively. The calculated values of the resonant and non-resonant branching ratio of $B\to K^{\ast }(892)\pi \pi$, $B\to K^{\ast }(892)K\pi$ and $B\to K^{\ast }(892)KK$ decay modes are compared with the experimental data. For $B\to K^{0\ast }(892){\pi }^{+}{\pi }^{-}$ and $B\to K^{0\ast }(892)K^{+}{K}^{-}$, the non-resonant contributions are about 70–80% of experimental data, for which the total results by considering resonant contributions are in good agreement with the experiment.

Recently, some small hints of lepton flavor violating (LFV) decays have been probed in different colliders and accelerators. Although these processes are forbidden in the Standard Model (SM), observation of LFV decays are considered as good probes to test theory beyond the SM. In this paper, we study some LFV decays, e.g. three-body decay channels of $\mu$ lepton like $\mu \to 3e$, $\mu \to e\nu \bar{\nu }$ and two-body decays of B meson and $\tau$ lepton like $B_{s,d}\to {\mu }^{\pm }{e}^{\mp }$ and $\tau \to e\varphi$ in $Z^{\prime }$ model. We calculate the branching ratio of the above decays considering the effect of both $Z$ and $Z^{\prime }$-mediated flavor-changing neutral-current (FCNC).

Lattice Monte Carlo simulations now include the effects of 2 light sea quarks and 1 strange sea quark through the use of an improved staggered fermion action. Consequently, results important to phenomenology are free of the approximate 10% errors inherent in the quenched approximation. This talk reports on calculations of the B and B_s, decay constants and B → πℓν form factors. Accurate determinations of these quantities will lead to tighter constraints on CKM matrix elements.

We study T violation in the three-body charmless baryonic decay of through the T-odd triple product correlation in the standard model. We find that the T violating asymmetry is 10%, which is accessible to the current B factories at KEK and SLAC, while the CP violating one 1.1%. We emphasize that this triple product correlation would be the first measurable direct T violating effect predicted in the standard model.

We review the direct CP and T violation in the three-body baryonic B decays in the standard model. In particular, we emphasize that the direct CP violating asymmetry in is around 22% and the direct T violating asymmetry in can be as large as 12%, which are accessible to the current B factories at KEK and SLAC as well as SuperB and LHCb.

We study ${\bar{B}}_s\to \varphi {\mu }^{+}{\mu }^{-}$ decay in the $G(211)$ model and vector leptoquark model, respectively. We consider the effects of these two new physics (NP) models on some measured physical observables of this decay process, such as the differential branching fraction and the angular distributions. We find that the large deviation of the differential branching fraction between the measurement and the Standard Model (SM) prediction can be explained in these two NP models. However, we found that not all observables of the double-lepton polarization asymmetries are sensitive to the contributions of these NP models.

The most precise measurement of decay-time-dependent CP violation in the decays of $B^0\to J/\psi K_S^0$ and $B^0\to \psi (2S)K_S^0$ was reported by LHCb collaboration with the values of $S_{J/\psi K_S^0}=0.83\pm 0.08\pm 0.01,C_{J/\psi K_S^0}=0.12\pm 0.07\pm 0.02$ and $S_{\psi (2S)K_S^0}=0.84\pm 0.10\pm 0.01,$$C_{\psi (2S)K_S^0}=-0.05\pm 0.10\pm 0.01$. In this study, the parameters of CP violation in these decay modes have been calculated under the factorization approach. In these decays, CP violation in the interference of mixing and decay has has arisen from decay-time-dependent asymmetry. This type of CP violation has been characterized by $\mathrm{\text{Im}}{\lambda }_f\ne 0$. We have estimated the parameters of $S_{J/\psi K_S^0}=0.88\pm 0.00$ and $C_{J/\psi K_S^0}=0.11\pm 0.01$ for the $B^0\to J/\psi K_S^0$ decay and $S_{\psi (2S)K_S^0}=0.89\pm 0.01$ and $C_{\psi (2S)K_S^0}=-0.04\pm 0.02$ correspond to the $B^0\to \psi (2S)K_S^0$ decay which are compatible with the experimental values approved by the LHCb collaboration. In the following, we have obtained the value of $sin2\beta$. Finally, we have calculated the total amplitude and obtained comparable results with the experimental values for the branching ratios of both decays.

We report on preliminary measurements of time-dependent CP-violation asymmetries in charmless neutral B meson decays to K⁺K^-K⁰ (including resonant decays ϕK⁰ and f₀(980)K⁰), η'K⁰, , , , , . The results are obtained from a data sample of up to 347 million pairs produced by e⁺e^- annihilation at the ϒ(4S) resonance collected with the BABAR detector at the PEP-II asymmetric-energy B-meson Factory at SLAC.

We present recent results on time integrated and time dependent CP violation for charmless hadronic B decays using BABAR detector at the PEP-II B-factory.