Related papers: Probing new physics effects in $\Lambda_b \to \Lam…
We study the decays of $\Lambda_b \to \Lambda(\to p \pi^-) \ell ^+ \ell^-$ with $\ell = (e, \mu, \tau)$. In particular, we examine the full angular distributions with polarized $\Lambda_b$ and identify the time-reversal asymmetries or T-odd…
Recently several measurements in the neutral current sector $b\rightarrow s l^+l^-$ ($l=e$ or $\mu$) as well as in the charged current sector $b \rightarrow c \tau \bar{\nu}$ show significant deviations from their Standard Model…
Rare decays of the kind $B\to K^*\mu^+\mu^-$ and $B_s\to \phi\mu^+\mu^-$ are key players for testing the Standard Model. The current experimental data for their decay rates and angular observables show tensions with the theoretical…
Recently, it was argued that new-physics (NP) effects in B decays can be approximately parametrized in terms of a few quantities. As a result, CP violation in the $B$ system allows one not only to detect the presence of new physics (NP),…
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 investigate the possible sizes of all the CP-violating asymmetries offered by the angular distribution of rare decay $\Lambda_b\rightarrow \Lambda(\to p \pi^-) \ell^+\ell^-$ in the Standard Model and new physics scenarios motivated by…
Recent experimental results in $B$ physics from Belle, BaBar and LHCb suggest new physics (NP) in the weak $b\to c$ charged-current and the $b\to s$ neutral-current processes. Here we focus on the charged-current case and specifically on…
The increasing number of flavour anomalies motivates the investigation of new processes where tensions similar to the observed ones may emerge. It is necessary to identify observables sensitive to physics beyond the Standard Model. The…
The deviations with respect to the Standard Model that are currently observed in $b \to s \ell\ell$ transitions, or $B$ anomalies, can be interpreted in terms of different New Physics (NP) scenarios within a model-independent effective…
We adopt an effective-lagrangian approach to compute the new-physics contributions to T-violating triple-product correlations in charmless Lambda_b decays. We use factorization and work to leading order in the heavy-quark expansion. We find…
The LHCb experiment, bolstered up by the 10^12 b-hadrons to be produced yearly in its interaction region, is an excellent place to study rare B decays. Flavor-changing neutral currents are forbidden at tree level in the Standard Model. They…
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 investigate the angular decay distribution of the four-fold $B_{c}\to D^{\ast}_{s}(\to D_{s}\gamma)\mu^{+}\mu^{-}$, and $B_{c}\to D^{\ast}_{s}(\to D_{s}\pi)\mu^{+}\mu^{-}$ decays that proceed through $b\to s\mu^{+}\mu^{-}$ quark level…
We propose a rather general description of residual New Physics (NP) effects on the top quark couplings. These effects are described in terms of 20 gauge invariant $dim=6$ operators involving gauge and Higgs bosons as well as quarks of the…
Measurement of $CP$-violating observables in semileptonic decays is a sensitive null-test of the Standard Model: any $CP$ violation would be an unambiguous sign of New Physics effects. The model-independent technique to measure parity and…
The rare decay B to K* (to K pi) mu+ mu- is regarded as one of the crucial channels for B physics since its angular distribution gives access to many observables that offer new important tests of the Standard Model and its extensions. We…
We study potential New Physics effects in the $\bar B \to D^{(*)} \tau \bar\nu$ decays. As a particular example of New Physics models we consider the class of leptoquark models and put the constraints on the leptoquark couplings using the…
The combined LEP/SLD data on the b\bar b forward-backward asymmetry from the Z-pole measurements may imply the presence of new physics in the $Zb\bar b$ couplings. In general, the effect of new physics can be parameterized by $SU_C(3)\times…
Flavour Changing Neutral Current (FCNC) decays are forbidden at lowest perturbative order in the Standard Model (SM) and only allowed via quantum loops. These transitions are therefore heavily suppressed in the SM, and New Physics (NP) can…
The rare B_s-> \phi \ell^+ \ell^- decay is investigated by using the most general model independent effective Hamiltonian for $\ell= \mu, \tau$. The calculated $Br(B_s \rar \phi \mu^+ \mu^-) = 1.92 \times 10^{-6}$ is in consistent with the…