Related papers: Probing New Physics in $B\to K^{(*)} \ell^+\ell^-$…
It is well known that New Physics can contribute to weak decays of heavy mesons via virtual processes during its decays. The discovery of New Physics, using such decays is made difficult due to intractable strong interaction effects needed…
The rare decays $B^0 \to D_s^- K^+$ and $B^+ \to D_s^+ \bar{K}^0$ can occur only via annihilation type diagrams in the standard model. We calculate these decays in perturbative QCD approach. We found that the calculated branching ratio of…
We study the rare radiative leptonic decays $B_s\to\ell^+\ell^-\gamma$ ($\ell=e,\mu,\tau$) within the Standard Model, considering both the structure-dependent amplitude and bremsstrahlung. In the framework of the covariant confined quark…
Form factors of the rare $\Lambda_{b}(\Lambda_{b}^*)\to N\ell^{+}\ell^{-}$ decays are calculated in the framework of the light cone QCD sum rules by taking into account of the contributions from the negative parity baryons. Using the…
We have extracted the ratio $|V_{ub}|/|V_{cb}|$ from a combined study of the available inputs on $\bar{B}\to (\pi,\rho,\omega)\ell^- \bar{\nu}_{\ell}$ and $\bar{B}(\bar{B}_s)\to (D^{(\ast)}, D_s^{(\ast)})\ell^- \bar{\nu}_{\ell}$ ($\ell =…
Using the responsible form factors calculated via full QCD, we analyze the $\Lambda_{b}\rightarrow \Lambda \ell^{+}\ell^{-}$ transition in the standard model containing fourth generation quarks (SM4). We discuss effects of the presence of…
We analyze the exclusive rare $B \to K^{(*)} \ell^+ \ell^-$, $B \to K^{(*)} \nu \bar \nu$ and $B \to K^* \gamma$ decays in the Applequist-Cheng-Dobrescu model, which is an extension of the Standard Model in presence of universal extra…
We study the differential decay rate for the rare decay $\Lambda_b\to \Lambda(1520)(\to NK)\ell^+\ell^-$ where $\ell$ is a light lepton, as this decay mode can provide new and complementary constraints on the Wilson coefficients in $b\to…
Rare $b\to s\ell^+\ell^-$ decays provide some of the most sensitive tests of the Standard Model and require precise and systematically improvable hadronic input from lattice QCD. For the phenomenologically important channel $B\to…
An analysis of the rare B decays $B\to K^{(*)}\nu\bar\nu$ is presented both within the SM and beyond. The SM predictions for the branching ratios are updated and uncertainties reduced. For the NP analysis both a model independent approach…
The long-distance and non-local parts of the form factors describing the single-photon mediated $K_{S,L}\to\pi^0\gamma^*\to\pi^0\ell^+\ell^-$ ($\ell = e, \mu$) transitions in the standard model are addressed in QCD in the limit where the…
In the pursuit of physics beyond the Standard Model, a promising path is the study of B-meson decays caused by the transition $b \to s\ell^+\ell^-$. A key observable in such decays is the ratio $R_K$, which measures electron--muon…
We investigate the angular distributions of the rare B decay, $B \to K^* (\to K \pi) \ell^+ \ell^-$, in general supersymmetric extensions of the standard model. We consider the new physics contributions from the operators $O_{7,8,9,10}$ in…
We reassess the $B\to\pi\ell\nu_{\ell}$ differential branching ratio distribution experimental data released by the BaBar and Belle Collaborations supplemented with all lattice calculations of the $B\to\pi$ form factor shape available up to…
In the framework of QCD factorization, we study $B^{+(0)} \to \eta' K^{+(0)}$ decays. In order to more reliably determine the phenomenological parameters $X_H$ and $X_A$ arising from end-point divergences in the hard spectator scattering…
We perform an improved perturbative QCD study of the decays $B_c^+ \to \eta_c L^+$,where $L$ denotes the light ground-state pseudoscalar, vector mesons and the corresponding $p$-wave scalar, axial-vector, and tensor ones, and predict their…
We consider the exclusive decays $B \to D^{(*)}\,\ell \bar\nu$ and study the effect of non $V-A$ structures on the observables. We extend the standard model hadronic current by additional right-handed vector as well as left- and…
This paper describes a determination of the Cabibbo-Kobayashi-Maskawa matrix element $|V_{cb}|$ using the decay $B^0\to D^{*-}\ell^+\nu_\ell$. We perform a combined measurement of this quantity and of the form factors $\rho^2$, $R_1(1)$,…
We study the exclusive $b \to u \ell^- \bar{\nu}_{\ell} (\ell=\tau,\mu,e)$ decays in the MSSM with and without R-parity violation. From the experimental measurements of branching ratios $\mathcal{B}(B^-_u \to \tau^- \bar{\nu}_{\tau})$,…
We study the exclusive rare decay B -> K l(bar) l. We calculate the relevant form factors within a relativistic constituent quark model, for the first time without employing the impulse approximation. The calculated form factors are used to…