相关论文: Probing new physics through $B^*_s \rightarrow \mu…
B physics has played a prominent role in investigations of new physics effects at low-energies. Presently, the largest discrepancy between a standard model prediction and experimental measurements appears in the branching ratio of the…
For any new physics possibly emerging in the future B experiments, the problem is how to extract the signals from the SM background. We consider the decay $b\to s s\bar d$ which is very small in the SM. In the MSSM this decay is possibly…
The observation of $B \to \tau \bar{\mu} + \mu \bar{\tau} $ at present experiments would be a clear sign of new physics. In this paper we calculate this process in a 2HDM framework where the decay is mediated by the exchange of spin zero…
We derive constraints on Wilson coefficients of dimension-six effective operators probing the b --> s transition, using recent improved measurements of the rare decays Bs --> mu+mu-, B --> K mu+mu- and B --> K* mu+mu- and including all…
We consider leptonic $B^-\to \ell^- \bar\nu_\ell$ and semileptonic $\bar B \to \pi \ell^- \bar\nu_\ell$, $\bar B \to \rho \ell^- \bar\nu_\ell$ decays and present a strategy to determine short-distance coefficients of New-Physics operators…
The decay modes $\bar{B}_s \rightarrow \pi^0(\rho^0 )\,\eta^{(')} $ are dominated by electroweak penguins that are small in the standard model. In this work we investigate the contributions to these penguins from a model with an additional…
The rare decay B -> K* nu anti-nu allows a transparent study of Z penguin and other electroweak penguin effects in New Physics (NP) scenarios in the absence of dipole operator contributions and Higgs (scalar) penguin contributions that are…
The significant divergence between the SM predictions and experimental measurements for the ratios, $R_{D^{(*)}}\equiv \mathcal{B}(\bar{B}\to D^{(*)}\tau^- \bar{\nu}_\tau)/ \mathcal{B}(\bar{B}\to D^{(*)} \ell^{\prime-}…
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…
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…
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…
In this work, we study the decays $\Lambda_c \to (\Lambda, n) \ell^+ \nu_\ell$ ($\ell = \mu, e$) within a model-independent framework. We calculate the helicity amplitudes for all possible four-fermion operators, including the interactions…
In this paper the potential for the discovery of new physics in the exclusive decay $\bar{B}_d \to \bar{K}^{*0} \mu^+ \mu^-$ is discussed. Attention is paid to constructing observables which are protected from uncertainties in QCD form…
Recent experimental results for the ratios of the branching fractions of the decays $\bar{B} \to D^{(*)} \tau \bar\nu$ and $\bar{B} \to D^{(*)} \mu \bar\nu$ came as a surprise and lead to a discussion of possibility of testing New Physics…
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…
We analyze the possibility of having new physics effects in the decay rate difference, $\Delta \Gamma_d$, of neutral $B_d$ mesons. Three different sources of enhancement are considered, CKM unitarity violations, beyond standard model…
One of the main indications for New Physics in rare $B$-decays is deduced from the tension between experimental and Standard Model predictions of the angular analysis of the $B^0 \to K^{*0} \mu^+\mu^-$ decay. There are however possible…
The leptonic decay $B_s \to \mu^+\mu^-$ is both rare and theoretically clean, making it an excellent probe for New Physics searches. Due to its helicity suppression in the Standard Model, this decay is particularly sensitive to new…
We derive model-independent bounds on the form factors for the decay $B_c^+ \to \eta_c\, \ell^+\, \nu$ including full mass effects, i.e. $\ell = e,\, \mu, \text{ and } \tau$. The bounds are obtained by using the BGL parameterization for the…
Results are reported for the B$^0_\mathrm{s}\to\mu^+\mu^-$ branching fraction and effective lifetime and from a search for the decay B$^0\to\mu^+\mu^-$. The analysis uses a data sample of proton-proton collisions accumulated by the CMS…