Related papers: Looking for the effects of New Physics in the $\La…
Extensions of the Standard Model which involve a new scale, $\Lambda$, may, for energies sufficiently small compared to this new scale, be expressed in terms of operators with energy dimension greater than four. The coefficients of just…
We make a systematic analysis of the effects of new physics in the B decay amplitudes on the CP asymmetries in neutral B decays. Although these are expected to be smaller than new physics effects on the mixing amplitude, they are easier to…
We study the $\bar{B}\to D(D^*) \ell^-\bar{\nu}_{\ell}$ decays based on the up-to-date available inputs from experiments and the lattice. First, we review the standard model (SM) predictions of the different observables associated with…
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 status of tests of the standard electroweak model and of searches for new physics in allowed nuclear $\beta$ decay and neutron decay is reviewed including both theoretical and experimental developments. The sensitivity and…
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…
In the Standard Model, the photon emitted in b->s\gamma decays is predicted to be left-handed polarized. We discuss the types of New Physics which can produce a deviation from this prediction, focusing on the Minimal Supersymmetric Standard…
We study the implications for $\Lambda_b \to \Lambda_c^*\ell\bar{\nu}_\ell$ and $\Lambda_b \to \Lambda_c^*\pi^-$ $[\Lambda_c^*=\Lambda_c(2595)$ and $\Lambda_c(2625)]$ decays that can be deduced from heavy quark spin symmetry (HQSS).…
Measurements from the LHCb experiment and $B$ factories have revealed several discrepancies in angular observables of rare semileptonic $B$ decays involving the quark-level transition $b \to s \ell^+ \ell^-$. In this work, we conduct a…
We present a systematic analysis for the rare baryonic exclusive decays of $\Lambda_b\to\Lambda l^+ l^- (l=e,\mu,\tau)$. We study the differential decay rates and the di-lepton forward-backward, lepton polarization and various CP…
We study the decays of $\Lambda_b \to \Lambda_c(\to B_n f) \ell ^- \overline{\nu}$ with $\ell = e, \mu, \tau$, where $B_n$ and $f$ are the daughter baryons and the rest of the particles in $\Lambda_c$ cascade decays, respectively. In…
We discuss possible new physics (NP) effects beyond the standard model (SM) in the exclusive decays $\bar{B}^0 \to D^{(\ast)} \tau^- \bar{\nu}_{\tau}$. Starting with a model-independent effective Hamiltonian including non-SM four-Fermi…
The rare four-fold decay $B_s \to K^*(\to K\pi)\mu^+\mu^- $, governed by the flavor-changing neutral current transition $b \to d\mu^+\mu^-$, provides a sensitive probe for testing the Standard Model (SM) and investigating signatures of new…
The recent successes of the SM do not weaken the arguments in favour of New Physics residing at the TeV scale. Finding and identifying it represents the prime challenge for a generation of high energy physicists. To differentiate between…
Effective theories provide a powerful tool for testing the Standard Model and for searching for the effects of new physics in a model-independent manner. In general one assumes that the effects of new physics characterized by a high-energy…
We conduct a systematic study of the impact of new physics in quark-level $b \to c \bar{c} s$ transitions on $B$-physics, in particular rare $B$-decays and $B$-meson lifetime observables. We find viable scenarios where a sizable effect in…
We have recently seen new upper bounds for $B^0_s\to \mu^+\mu^-$, a key decay to search for physics beyond the Standard Model. Furthermore a non-vanishing decay width difference $\Delta\Gamma_s$ of the $B_s$ system has been measured. We…
No matter what the scale of new physics is, deviations from the Standard Model for the Higgs observables will indicate the existence of such a scale. We consider effective six dimensional operators, and their effects on the Higgs…
We study the possible effects of TeV scale new physics (NP) on the rate for Higgs boson decays to charged leptons, focusing on the tau tau channel which can be readily studied at the Large Hadron collider. Using an SU(3)_C X SU(2)_L X…
We study the $d^2 \Gamma_d /(d\omega d\cos\theta_d) $, $d\Gamma_d /d\cos\theta_d$ and $ d\Gamma_d /dE_d $ distributions, which are defined in terms of the visible energy and polar angle of the charged particle from the $\tau-$decay in $b\to…