相关论文: Vector Quark Model and B to X_s gamma Decay

Motivated by the recent experimental progress on the $R_{D^{(\ast)}}$ and $R_{K^{(\ast)}}$ anomalies in $B$-decays, we consider an extension of the Standard Model by a single vector leptoquark field. We study how one can achieve the…

I point out that $B \to X_q \l^+ \l^-$ decays $(q = s, d)$ are sensitive probes of possible violation of CKM unitarity. I compute the decay rates and asymmetries in a minimal extension of the Standard Model containing an additional…

Neutral $B$ meson mixing matrix elements and $B$ meson decay constants are calculated. Static approximation is used for $b$ quark and domain-wall fermion formalism is employed for light quarks. The calculations are carried out on $2+1$…

The theoretical status of NNLO QCD corrections to the inclusive radiative anti-B -> X_s gamma decay in the standard model is briefly overviewed. Emphasis is put on recent results for three-loop fermionic corrections to matrix elements of…

We study the (tree-level) weak radiative decays of $B$ mesons. We present a numerical estimate for the inclusive $b \to X_c \gamma (\gamma)$ modes based on the free-quark decay. We then review what is known for the $B \to D^\star \gamma$…

In the models with vector like quark doublets, the mass matrices of up and down type quarks are related. Precise diagonalization for the mass matrices became an obstacle in the numerical studies. In this work we propose a diagonalization…

We evaluate constraints from flavor changing rare meson decays to a light vector boson $X$, followed by the decay of the on-shell $X$ into the SM fermions. The flavor changing meson decay emitting the light $X$ is induced by loop processes…

The study investigates flavor-changing neutral current (FCNC) decays of $B$ and $K$ mesons in the context of a dark $U(1)_D$ model with a dark photon/dark $Z$ mass between 10 MeV and 2 GeV. While the model improves the fit to certain decay…

Radiative $\bar{B}^0(\bar{B}^0_s)\rightarrow J/\psi \gamma$ decays provide an interesting case to test our understanding of (non)perturbative QCD and eventually to probe physics beyond the standard model. Recently, the LHCb Collaboration…

The hadronic charmless B decays into a scalar meson and a vector meson are studied within the framework of QCD factorization. The main results are: (i) The decay rates for the $f_0(980)K^{*-}$ and $f_0(980)\ov K^{*0}$ modes depend on the…

The updated analysis of the LHCb Collaboration on the lepton flavor violation suggests that the new physics should couple to muons and electrons with comparable magnitudes, resulting in the anomalies in both rare decay channels, $b…

We review the NLL QCD calculations for the branching ratio of B -> X_s gamma in the SM. In particular, we emphasize the problem related to the definition of the charm quark mass which leads to a rather large uncertainty of the NLL…

We demonstrate a method for calculating the neutral B-meson decay constants and mixing matrix elements in unquenched lattice QCD with domain-wall light quarks and static b-quarks. Our computation is performed on the "2+1" flavor gauge…

We present within the Standard Model the exclusive radiative decays B -> K*/rho gamma and B_(s/d) -> gamma gamma in QCD factorization based on the heavy-quark limit m_b >> Lambda_QCD. For the decays with a vector meson in the final state we…

We calculate the P0 to gamma gamma, V0 to P0 gamma and V0to V'0 gamma gamma decays in the framework of a U(3)xU(3) linear sigma model which includes constituent quarks. For the first two decays this approach improves results based on the…

In the supersymmetric standard model, the radiative $B$-meson decay $B \to X_s \gamma$ could receive a large contribution from a new source of flavor-changing neutral current, which also violates CP invariance. The CP-conjugate processes…

We discuss the consequences of deviations from the Standard Model observed in $b\to s\mu^+\mu^-$ transitions for flavour-changing neutral-current processes involving down-type quarks and neutrinos. We work within an effective field theory…

The flavor changing neutral current processes $K_L \to \pi^0 e^+ e^-$, $B \to X_s e^+ e^-$ and $B \to X_s \mu^+ \mu^-$ are studied within the minimal supersymmetric extension of the Standard Model. We first examine the rates for these decay…

Recently, we studied the branching ratios of rare K and B decays in models with Minimal Flavor Violation (MFV) using the presently available information from the universal unitarity triangle analysis and from the measurements of Br(B -> Xs…

The element |V_{ub}| of the quark mixing matrix can be extracted with small theoretical uncertainties by combining weighted integrals over the endpoint regions of the lepton spectrum in B -> X_u l nu decays and the photon spectrum in B ->…