Related papers: $B$ anomalies with unparticles
The ratios of branching fractions $\mathcal{R}(D^{*})\equiv\mathcal{B}(\bar{B}\to D^{*}\tau^{-}\bar{\nu}_{\tau})/\mathcal{B}(\bar{B}\to D^{*}\mu^{-}\bar{\nu}_{\mu})$ and $\mathcal{R}(D^{0})\equiv\mathcal{B}(B^{-}\to…
Deviation from the standard model prediction is observed in many semileptonic $B$ decays mediated via $b \to c$ charged current interactions. In particular, current experimental measurements of the ratio of branching ratio $R_D$ and…
The recent Belle and BaBar measurements of the branching ratio of $B^+ \to \tau^+ \nu_\tau$ indicate a significant deviation from the Standard Model prediction. We demonstrate that this measurement has a serious impact on models with…
The measurement of $R_D$ ($R_{D^*}$), the ratio of the branching fraction of $\overline{B} \to D \tau \bar{\nu}_\tau (\overline{B} \to D^* \tau \bar{\nu}_\tau)$ to that of $\overline{B} \to D l \bar{\nu}_l (\overline{B} \to D^* l…
We examine the effects of an unparticle $\mathcal{U}$ as a possible source of missing energy in the p-wave decays of $B$ meson. The dependence of the differential branching ratio on the $K_{0}^{\ast}(K_{1}) -$% meson's energy is discussed…
Using a sample of 3.3 million B-meson decays collected with the CLEO detector at the Cornell Electron Storage Ring, we have studied $B^- \to D^0 \ell\nu$ and $\bar{B}^0 \to D^+ \ell\nu$ decays, where $\ell$ can be either an electron or…
We present a measurement of the $B^{0} \rightarrow D^{*-} \ell^{+} \nu_{\ell}$ ($\ell=e,\mu$) branching ratio and of the CKM parameter $|V_{cb}|$ using signal decays accompanied by a fully reconstructed $B$ meson. The Belle II data set of…
We present measurements of the semileptonic decays B- --> D0 tau- nubar, B- --> D*0 tau- nubar, B0bar --> D+ tau- nubar, and B0bar --> D*+ tau- nubar, which are potentially sensitive to non--Standard Model amplitudes. The data sample…
Decays of the kind $B^0_{s,d}\to\ell^+\ell^-$ belong to the most favourable processes for probing the flavour structure of the Standard Model, with outstanding sensitivity to new (pseudo)-scalar contributions. While the branching ratio of…
Deviations from the standard model prediction have been observed not only in $b \to c$ charged current interactions but also in $b \to s$ flavor changing neutral current interactions. In particular, the deviation observed in the measured…
Semileptonic and purely leptonic decays of B meson to $\tau$, such as $B\to D^{(\ast)}\tau\nu_{\tau}$ and $B\to\tau\nu_\tau$ are studied. Recognizing that there already were some weak hints of possible deviations from the SM in the…
With the full data sample of $772 \times 10^6$ $B{\bar B}$ pairs recorded by the Belle detector at the KEKB electron-positron collider, the decay $\bar{B} \rightarrow D^* \tau^- \bar{\nu}_\tau$ is studied with the hadronic $\tau$ decays…
We present preliminary measurements of branching fractions for the semileptonic decays B --> D tau nubar and B --> D* tau nubar, which are potentially sensitive to non--Standard Model amplitudes. The data sample comprises 232x10^6…
The $\bar{B}_s^0 \to D_s^{(*)+} l^- \bar{\nu}_l$ semileptonic decays were calculated in the framework of the standard model (SM) by employing the perturbative QCD (pQCD) factorization approach. We defined four ratios of the branching ratios…
We report results from a study of $B^\pm \rightarrow DK^\pm$ decays followed by $D$ decaying to $CP$~eigenstates, where $D$ indicates a $D^0$ or $\bar{D}^{0}$ meson. These decays are sensitive to the Cabibbo-Kobayashi-Maskawa…
We presented at Moriond EW 2025 a measurement of the branching fraction of $B\to\tau\nu$ decays using $(387\pm 6) \times 10^6$ $\Upsilon (4S)$ collected between 2019 and 2022 with the Belle~II detector at the SuperKEKB $e^+e^-$ collider. We…
We present a search for the decay $B^{+} \to \tau^{+} \nu_{\tau}$ in $88.9 \times 10^{6}$ $\Upsilon(4S)$ decays recorded with the BABAR detector at the SLAC $B$-Factory. A sample of semi-exclusive, semi-leptonic B decays ($B^{-} \to D^{0}…
The b to d d s bar transition gives extremely small branching ratios within the standard model, thus providing an appropriate ground for testing new physics. Using renormalization group technique we determine the Wilson coefficients and the…
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…
The anomalously large experimentally measured ratios of the semitauonic decay $B\rightarrow D^{(*)} +\tau+\nu$ and the corresponding semileptonic $B\rightarrow D^{*} +\l+\bar{\nu}_l$ disagree with the predictions of the standard E.W + QCD…