Related papers: Exclusive (Lambda_b -> Lambda l^+ l^-) decay beyon…
We present the first lattice QCD determination of the $\Lambda_b \to \Lambda$ transition form factors that govern the rare baryonic decays $\Lambda_b \to \Lambda l^+ l^-$ at leading order in heavy-quark effective theory. Our calculations…
We examine in detail the semi-leptonic decay $\Lambda_b \to \Lambda_c \tau{\bar \nu}_{\tau}$, which may confirm previous hints, from the analogous $B$ decay, of a new physics beyond the standard model. First of all, starting from rather…
We present, for the first time, the six-fold differential decay density expression for $\Lambda^0_b\to\Lambda^+_{c} l^- \bar{\nu}_{l}$, taking into account the polarisation of the $\Lambda^0_b$ baryon and a complete basis of new physics…
Using the most general, model independent effective Hamiltonian, the rare B_s ->\gamma \nu \bar{\nu} decay with polarized photon is studied. The sensitivity of the branching ratio and photon polarization to the new Wilson coefficients are…
We study long-distance effects in rare exclusive semileptonic decays B -> (K, K*) (l+ l-, nu bar{nu}) and analyze dilepton spectra and asymmetries within the framework of the Standard Model. The form factors, describing the meson transition…
Motivated by the LHCb measurement of the hyperon decay mode $\Sigma^+\to p\mu^+\mu^-$ and prospects for improvement, we revisit the estimates for the rate and muon forward-backward asymmetry within the standard model and beyond. The…
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…
Using the general, model independent form of effective Hamiltonian, the decay spectrum of B^0 -> pi^+ pi^- l^+ l^- decay is studied. The sensitivity of experimentally measurable asymmetries to the new Wilson coefficients and time is…
We propose two different and complementary observables for singling out possible signals of physics beyond the standard model in the semi-leptonic decays $\Lambda_b \to \Lambda_c \ell{\bar \nu}_{\ell}$, both with the $\tau$ lepton and with…
The semi-leptonic baryonic $b\to s$ decay, $\Lambda_b\rightarrow \Lambda \ell^+\ell^-$, has been studied and new angular observables and asymmetries have been proposed which can test the presence of new physics beyond the standard model.
We update the standard model predictions for the branching ratios of the decays B -> (K,K*,Xs) l^+ l^-, with l=e,mu. Using the measurements of BR(B -> Xs gamma) and BR(B -> K l^+ l^-) as well as the upper limits on BR(B -> (K*,Xs) l^+…
We present a study of the rare baryonic decay $\Lambda_b \to \Lambda \tau^+ \tau^-$ as a probe of new physics (NP) coupled preferentially to third-generation fermions. Within the Standard Model, we evaluate the branching ratio and the…
The exclusive weak decay of $\Lambda_b \to \Lambda \gamma$ and $\Lambda_b \to \Lambda l^{+} l^{-}$ are investigated in the Applequist-Cheng-Dobrescu model, which is an extension of the standard model in presence of universal extra…
Polarized forward-backward asymmetries in the (B_s -> l^+ l^- gamma) decay are calculated using the most general, model independent form of the effective Hamiltonian, including all possible forms of interactions. The dependencies of 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…
The LHCb bounds on the branching ratio of rare decay $D^0 \to \mu^+ \mu^-$ and the constraints on the branching ratio of $D^+ \to \pi^+ \mu^+ \mu^-$ in the nonresonant regions enable us to improve constraints on new physics contributions.…
Using the most general model independent form of the effective Hamiltonian, the rare B_s --> \gamma \ell^+ \ell^- decays are studied by taking into account the polarization of the photon. The total and the differential branching ratios for…
The polarized lepton pair forward-backward asymmetries in (B -> rho l^+ l^-) decay using a general, model independent form of the effective Hamiltonian is studied. The general expression for nine double-polarization forward-backward…
Leptonic rare decays of $B^0_{s,d}$ mesons offer a powerful tool to search for physics beyond the Standard Model. The $B^0_{s}\to\mu^+\mu^-$ decay has been observed at the Large Hadron Collider and the first measurement of the effective…
Hadronic $\tau$ decays are studied as probe of new physics. We determine the dependence of several inclusive and exclusive $\tau$ observables on the Wilson coefficients of the low-energy effective theory describing charged-current…