Related papers: Comment on new physics contributions to Gamma_{12}…
We present a considerably improved analysis of model-independent bounds on new physics effects in non-leptonic tree-level decays of B-mesons. Our main finding is that contributions of about $\pm 0.1 $ to the Wilson coefficient of the…
The CP asymmetry in inclusive B->X_{s,d}+gamma decays is an important probe of new physics. The theoretical prediction was thought to be of a perturbative origin, and in the standard model, to be about 0.5 percent. In a recent work with M.…
We give a comprehensive account of the flavour physics of Beyond-Standard-Model (BSM) effects in $b \to c \bar{c} s$ transitions, considering the full set of 20 four-quark operators. We discuss the leading-order structure of their RG mixing…
The CP-violating charge asymmetry in decays K+- --> \pi+- \gamma\gamma, which is induced by the electromagnetic penguin operators, has been studied both in thestandard model and in its extensions. Because of a large enhancement of the…
The B-meson system offers interesting probes for the search of physics beyond the Standard Model. After addressing possible signals of new-physics contributions to the B -> phi K and B -> pi K decay amplitudes, we focus on the data for…
In contrast with $B^0-\bar B^0$, $B_s-\bar B_s$ mixing where the standard model (SM) contributions overwhelm that of new physics beyond standard model (BSM), a measured relatively large $D^0-\bar D^0$ mixing where the SM contribution is…
We investigate how far a new physics scenario affecting primarily the third generation fermions can ameliorate the tension between B-decay observables and Standard Model expectations. Adopting a model-independent approach, we find that…
This talk discusses possible new physics interpretations of recent experimental results on the B-->K*mu+mu- decay that show a discrepancy with the Standard Model predictions. A model independent analysis that takes into account all the…
B-B-bar mixing involves three physical parameters: the magnitudes of the off-diagonal elements of the mass and decay matrices and their relative phase. They are related to the mass and width differences between the mass eigenstates and to…
In left-right symmetric models, large contributions to the decay amplitude $b \rightarrow s+ \gamma$ can arise from the mixing of the $W_L$ and $W_R$ gauge bosons as well as from the charged Higgs boson. These amplitudes are enhanced by the…
We show that in the Standard Model the parametrically leading (by a factor 1/alpha_s) contribution to the inclusive CP asymmetry in B->X_{s,d}+gamma decays arises from a long-distance effect in the interference of the electromagnetic dipole…
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…
I review the signals for New Physics in CP-violating measurements in B and Lambda_b decays. I also discuss ways of identifying this New Physics, should such a signal be found.
The rare decays B_s -> \mu^+\mu^- and B -> K^{(*)}\mu^+\mu^- are sensitive to new particles and couplings via their interferences with the standard model contributions. Recently, the upper bound on B(B_s -> \mu^+\mu^-) has been improved…
As is well known, $B^0_{d,s}$--$\bar B^0_{d,s}$ mixing offers a profound probe into the effects of physics beyond the Standard Model. The data obtained at the $e^+e^-$ $B$ factories have already provided valuable insights into the…
Recently LHCb has announced a discrepancy of 3.7 sigma in one of the theoretically clean observables accessible through studies of angular correlations in B->K*mu+mu-. We point out that in the most minimal Z' setup that can address this…
In this short review we present the history, an overview of the analysis, and some personal comments on the anomalous like-sign dimuon charge asymmetry measurements by the D\O\ Collaboration.
The $ZZ\gamma$ triple neutral gauge couplings are absent in the Standard Model (SM) at the tree level. They receive no contributions from dimension-6 effective operators, but can arise from effective operators of dimension-8. We study the…
We study the sensitivity of $ e \gamma$ colliders to physics beyond the Standard Model, when such interactions are natural and their scale lies below the collider energy. Using the reaction $ e \gamma \to b t \nu$ as a specific example, we…
Electroweak interactions need three Nambu-Goldstone bosons to provide a mass to the W and the Z gauge bosons but they also need an ultra-violet moderator or new physics to unitarize the gauge boson scattering amplitudes. In this talk, I…