Related papers: Explaining the observed deviation in R($D^{(*)}$) …
Babar, Belle and recently LHCb has reported an excess in the measurements of $R(D^{*})$, $R(D)$ and $\mathcal{B}r(B \rightarrow \tau \nu_{\tau} )$ than expected from SM, a possible signature of lepton flavor universality violating NP. In…
The BaBar, Belle, and LHCb collaborations have reported evidence for new physics in $B\to D\tau\nu$ and $B\to D^*\tau\nu$ of approximately $3.8\sigma$. There is also the long lasting discrepancy of about $3\sigma$ in the anomalous magnetic…
The puzzle of $R(D^{(*)})$ associated with $B\to D^{(*)}\tau\nu$ decay is addressed in the two-HIggs-doublet model. An anomalous coupling of $\tau$ to the charged Higgs is introduced to fit the data from BaBar, Belle, and LHCb. It is shown…
Motivated by an anomaly in $R(D^{(*)})={\rm BR}(\bar{B}\rightarrow D^{(*)} \tau^-\bar{\nu})/{\rm BR}(\bar{B}\rightarrow D^{(*)} l^-\bar{\nu})$ reported by BaBar, Belle and LHCb, we study $R(D^{(*)})$ in a general two Higgs doublet model…
Recently, several $B$-physics experiments have reported an appreciable deviation from the Standard Model (SM) in the tree-level observables $R_{D^{(*)}}$; the combined weighted average now stands at $\approx 4 \sigma$. We first show the…
Recent experimental measurements of several observables in semileptonic B meson decays have pointed towards the possibility of new physics. The LHCb collaboration has reported a significant deviation, exceeding $3.2\sigma$, in the combined…
Based on the full BaBar data sample, we report improved measurements of the ratios R(D(*)) = B(B -> D(*) Tau Nu)/B(B -> D(*) l Nu), where l is either e or mu. These ratios are sensitive to new physics contributions in the form of a charged…
Based on the full BaBar data sample, we report improved measurements of the ratios R(D(*)) = B(B -> D(*) Tau Nu)/B(B -> D(*) l Nu), where l is either e or mu. These ratios are sensitive to new physics contributions in the form of a charged…
More than $3\sigma$ deviations from the standard model are observed in the angular observable $P'_5$ of $B\to K^* \mu^+ \mu^-$ and muon $g-2$. To resolve these anomalies, we extend the standard model by adding two leptoquarks. It is found…
Recently, the BaBar collaboration reported first evidence for new physics in B->D\tau\nu and B->D*\tau\nu. Combining both processes the significance is 3.4\sigma. This result cannot be explained in a two Higgs doublet model of type II.…
We study the influence of a charged-Higgs on the excess of branching fraction ratio, $R_M = BR(\bar B \to M \tau \bar\nu_\tau)/BR(\bar B \to M \ell \bar \nu_\ell)$ $(M=D, D^*)$, in a generic two-Higgs-doublet model. In order to investigate…
The LHC observed so far three deviations from the Standard Model (SM) predictions in flavour observables: LHCb reported anomalies in $B\to K^* \mu^+\mu^-$ and $R(K)=B\to K \mu^+\mu^-/B\to K e^+e^-$ while CMS found an excess in…
There are indications of a possible breakdown of the standard model, suggesting that $\tau$ lepton interactions violate flavor universality. BABAR, Belle and LHCb report high ratios of $B\to D^{(*)}\tau\nu$. There are long-standing excesses…
We discuss the Type-X (lepton-specific) two Higgs doublet model as a solution of the anomaly of the muon $g-2$. We consider various experimental constraints on the parameter space such as direct searches for extra Higgs bosons at the LEP II…
The deviation of the measurement of $R_{D}$ ($R_{D^{*}}$) from the Standard Model (SM) expectation is $2.3\sigma$ ($3.1\sigma$). $R_{D}$ ($R_{D^{*}}$) is the ratio of the branching fraction of $\overline{B} \rightarrow…
In recent times, one of the strongest hints of Physics Beyond the Standard Model (BSM) has been the anomaly in the ratios $R_D$ and $R_{D^\ast}$ measured in the charged current decays of $B$-mesons. In this work, we perform a comprehensive…
In recent years, exciting (indirect) hints for physics beyond the Standard Model (SM) have been accumulated. In particular, semi-leptonic $B$ decays show deviations from the SM predictions, which, due to the ratios $R(K^{(*)})$ and…
Among so-called three 3-sigma anomalies in high energy physics, the excess of the branching ratio $W^- \to \tau \bar \nu_\tau$ with respect to the electrons and muons is especially interesting because (1) in the standard model (SM),…
The semitauonic decay $\bar{B} \rightarrow D^* \tau^- \bar{\nu}_\tau$ is sensitive to new physics beyond the Standard Model (SM) that has an enhanced coupling to the $\tau$ lepton. In the ratio of branching fractions $R(D^*) =…
The following is an overview of the measurements of the CKM matrix elements V_cb and V_ub that are based on detailed studies of semileptonic B decays by the BABAR and Belle Collaborations and recent advances in QCD calculations. In…