Related papers: B -> X_s l+ l- in the vectorlike quark model

Motivated by the recent measurement of the lepton flavour nonuniversality ratio $R_{K^*}$ by the LHCb Collaboration, we study the implications of vector leptoquarks on the observed anomalies associated with the $\bar B \to \bar K^* l^+ l^-$…

We propose a minimal extension of the Standard Model where an up-type vector-like quark, denoted $T$, is introduced and provides a simple solution to the CKM unitarity problem. We adopt the Botella-Chau parametrization in order to extract…

We present updated and comprehensive Standard Model predictions for the inclusive rare decay $B \to X_s \nu\bar{\nu}$. Using a state-of-the-art determination of the short-distance coefficient, including NLO QCD and electroweak effects, and…

$B_s - \bar B_s$ mixing has been measured recently by D0 and CDF. The range predicted in the standard model is consistent with data. However, the standard model central values for $\Delta M_{B_s}$ and also $\Delta M_ {B_d}$ are away from…

We study the heavy flavor conserved semi-leptonic decay $B_s\to B\ell\nu$ in the covariant light front approach. The covariant light front quark model is used to calculate the transition form factors of $B_s\to B^{(*)}$ as well as $D_s\to…

We present standard model (SM) estimates for exclusive $c \to u \gamma$ processes in heavy quark and hybrid frameworks. Measured branching ratios ${\cal{B}}(D^0 \to (\phi, \bar K^{*0}) \gamma)$ are at or somewhat exceeding the upper range…

The $B\rightarrow K_{2}^{\ast}(1430)l^{+}l^{-}$ $(l=\mu,\tau)$ decays are analyzed in the Standard Model extended to fourth generation of quarks (SM4). The decay rate, forward-backward asymmetry, lepton polarization asymmetries and the…

We construct a model based on the electroweak gauge group $\rm SU(2)_L \times SU(2)_R \times U(1)_{B-L}$ augmented by an $S_3$ symmetry. We assign nontrivial $S_3$ transformation properties to the quarks and consequently we need two scalar…

The observation of a sizable CP asymmetry in the inclusive decays B -> Xs gamma would be a clean signal of New Physics. In the Standard Model, this asymmetry is below 1 % in magnitude. In extensions of the Standard Model with new…

The radiative dileptonic decays B_s(B_d) -> l^+ l^- gamma (l = e, mu) are investigated within the Standard Model . The transition formfactors are calculated in the framework of the light cone QCD sum rules method and it is found that the…

Applying the effective Hamilton for $b\rightarrow sl^+l^-,\;(l=e,\;\mu)$ in the framework of minimal supersymmetric extension of the standard model with local $B-L$ gauge symmetry, we investigate branching ratios and forward-backward…

We study some non leptonic and semileptonic decays of $B_s$ meson into a final scalar meson $f_0(980)$ in the fourth quark generation model. Since the $f_0(980)$ meson is dominantly composed of ($s \bar s $) pair, the mixing induced CP…

We present preliminary results from a search for the flavor-changing neutral current decays B-->Kl^+l^- and B-->K^*(892)l^+l^- using a sample of 22.7 x 10^6 Upsilon(4S)-->B anti-B decays collected with the BABAR detector at the PEP-II B…

We study the branching ratios of rare K and B decays in models with minimal flavour violation, using the presently available information from the universal unitarity triangle analysis and from the measurements of Br(B -> X_s gamma), Br(B ->…

From the experimental branching ratios for $B^- --> \rho^0 l^-\bar\nu_l$ and $D^+ --> {\overl K}^{*0}({\overl K}^0) e^+ \nu_e$ one finds, in the Heavy Quark Limit of $HQET$, $ |V_{bu}|=(8.1\pm 1.7) x 10^{-3}$, larger but consistent with the…

We propose a spontaneous A4 flavor symmetry breaking scheme implemented in a warped extra dimensional setup to explain the observed pattern of quark and lepton masses and mixings. The main advantages of this choice are the explanation of…

The experimental information on b --> s l^+ l^- decays has grown enormously during the last couple of years due to BaBar, Belle, CDF and LHCb. Especially, exclusive modes B --> K^(*) l^+ l^-, which have the largest rate and are easily…

We derive the triply differential spectrum for the inclusive rare decay B -> Xs l+ l- in the shape function region, in which Xs is jet-like with $mX^2 \lesssim mb \Lambda_QCD$. Experimental cuts make this a relevant region. The perturbative…

We report new measurements of the differential and total branching ratios for inclusive B decay to D^0, D^+ and D^{*+} and the first measurement of the same quantities for inclusive B decay to $D^{*0}$. Here B is the mixture of B_d and B_u…

We present an analysis of exclusive charmless semileptonic B-meson decays based on 83 million BBbar pairs recorded with the BABAR detector at the Upsilon(4S) resonance. Using isospin symmetry, we measure branching fractions B(B0 --> pi- l+…