Related papers: B -> D tau nu Branching Ratios: Opportunity for La…
Experimental measurements of $R_{D}$, $R_{D^*}$ and $R_{J/\Psi}$ in $B \to (D,\,D^{\ast})l\nu$ and $B_c \to J/\Psi l \nu$ decays mediated via $b \to c\,l\,\nu$ charged current interactions deviate from standard model prediction by…
We scrutinize the impact of various relevant scalar leptoquarks on the physical observables associated with the rare semileptonic decay processes of $B_s$ meson involving $b \to (u, c) l\bar \nu_l$ quark level transitions. We constrain the…
In recent years, we used lattice QCD to calculate some quantities that were unknown or poorly known. They are the $q^2$ dependence of the form factor in semileptonic $D\to Kl\nu$ decay, the leptonic decay constants of the $D^+$ and $D_s$…
Semileptonic and leptonic B decays are analyzed in the framework of the relativistic quark model. Special attention is payed to the decays involving $\tau$ lepton. It is found that the calculated particular decay branching fractions are…
Experimental measurements collected by the BABAR, Belle, and LHCb experiments on different observables associated with the semileptonic transition $b \to c \tau \bar{\nu}_\tau$, indicate the existence of disagreement respect with the…
We make predictions and propose tests for the semi-leptonic decays $B\to D^{(*)} l \bar{\nu}_l$ and $\Lambda_b\to \Lambda_c l \bar{\nu}_l$, with $l$ = $e$, $\mu$ and $\tau$. Preliminarily, we study such processes according to the $\ell-s$…
Motivated by the anomalies present in $b \to u$ and $b \to c$ semileptonic decays, we study the corresponding $B_s \to (K,K^*) \tau \nu$ and $B \to \pi \tau \nu$ decays within an effective field theory formalism. Our analysis is based on a…
We present first lattice QCD results for semileptonic form factors for the decays $B_c \to \eta_c l \nu$ and $B_c \to J/\psi l \nu$ over the full $q^2$ range, using both improved non-relativistic QCD (NRQCD) and fully relativistic (HISQ)…
We extend the Standard Model with the general effective Hamiltonian for the quark level transition $c \to s \ell \nu$ with a complete set of four fermion operators including right-handed neutrinos. The current experimental measurements in…
Adding a hard photon to the final state of a leptonic pseudoscalar-meson decay lifts the helicity suppression and can provide sensitivity to a larger set of operators in the weak effective Hamiltonian. Furthermore, radiative leptonic $B$…
We perform a comprehensive analysis of scalar contributions in $b \to c \tau \nu$ transitions including the latest measurements of $R(D^{(*)})$, the $q^2$ differential distributions in $B \to D^{(*)} \tau \nu$, the $\tau$ polarization…
Latest Lattice results on $D$ form factors evaluation from first principles show that the standard model (SM) branching ratios prediction for the leptonic $D_s \to \ell \nu_\ell$ decays and the semileptonic SM branching ratios of the $D^0$…
We study $B_c \to (D,\,D^{\ast})\,l\,\nu$ semileptonic decays mediated via $b \to u\,l\,\nu$ charged current interactions using the $B_c \to (D,\,D^{\ast})$ transition form factors obtained in the covariant light front quark model. We give…
We study the rare $\Lambda_b\to\Lambda\mu^+\mu^-$ decay in the Standard Model and beyond. Beyond the Standard Model we include new vector and axial-vector operators, scalar and pseudo-scalar operators, and tensor operators in the effective…
The LHCb experiment at CERN's Large Hadron Collider will soon allow us to enter a new era in the exploration of B_s decays. A particularly promising channel for the search of "new physics" is B^0_s -> mu^+ mu^-. The systematic key…
The first observation of the semileptonic $b$-baryon decay $ \Lambda_b^0 \rightarrow \Lambda_c^+ \tau^-\overline{\nu}_{\tau}$, with a significance of $6.1\,\sigma$, is reported using a data sample corresponding to 3 fb$^{-1}$ of integrated…
The universality of the weak interactions can be tested in semileptonic $b \to c$ transitions, and in particular in the ratios $R(D^{(*)}) \equiv \Gamma(B \rightarrow D^{(*)} \tau \nu )/\Gamma(B \rightarrow D^{(*)} \ell \nu )$ (where $\ell…
The latest BaBar measurements of the ratios ${\cal R}(D^{(*)})=\displaystyle{\frac{{\cal B}(B \to D^{(*)} \tau {\bar \nu}_\tau)}{{\cal B}(B \to D^{(*)} \mu {\bar \nu}_\mu)}}$ deviate from the Standard Model predictions at the global level…
We study new physics effects on B decay processes including a final $\tau$ particle, namely $B \to D \tau \nu$ and $B \to \tau \nu$. An important feature of these processes is that a charged Higgs boson can contribute to the decay amplitude…
Physics beyond the Standard Model could be measured indirectly, through its effects on Standard Model observables. One place to look for such effects is in the semileptonic decays of B mesons. In order to constrain the possible role of new…