Related papers: $R_{D^*}$ or $R_{D\pi}$: closing the theoretical g…
Discrepancies between Standard Model predictions and experimental measurements of the fractions R_c and R_b of hadronic Z decays to charm and bottom are investigated. We show that there exists a discrepancy in two complementary…
The Belle Collaboration has recently measured the complete set of angular coefficient functions for the exclusive decays $\bar B \to D^* (D \pi) \ell \bar \nu_\ell$, with $\ell=e,\,\mu$, in four bins of the parameter…
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…
Deviations from the standard model prediction have been observed in several leptonic and semileptonic $B$ meson decays to $\tau\nu$ final states mediated via $b \to u$ and $b \to c$ charged current interactions. The measured value of ratio…
Semileptonic $b \to c$ transitions, and in particular the ratios $R(D^{(*)}) = \frac{\Gamma(B \rightarrow D^{(*)} \tau \nu )}{\Gamma(B \rightarrow D^{(*)} \ell \nu )}$, can be used to test the universality of the weak interactions. In light…
The ratio of branching ratios in leptonic pion decay $R_{\pi} \equiv (\Gamma(\pi^- \to e \nu_e))/(\Gamma(\pi^- \to \mu \nu_\mu))$ is a powerfully sensitive probe of new interactions beyond the electroweak standard model. This is due to the…
The decays D^* -> D\pi and D^* -> D\gamma are well described by heavy meson chiral perturbation theory. With the recent measurement of Br(D^{*+} -> D^+ \gamma), the D^{*0}, D^{*+}, and D_s^* branching fractions can be used to extract the…
Theoretical efforts to describe and explain the $\eta\to 3\pi$ decays reach far back in time. Even today, the convergence of the decay widths and some of the Dalitz plot parameters seems problematic in low energy QCD. In the framework of…
B --> K^* \pi and B --> \rho K decays involve the same quark-level processes as B --> \pi K. Analyzing the measurements of the former decays might be able to shed additional light on the new-physics hints in the current B --> \pi K data. We…
Recent measurements of the branching fraction for D_s -> l nu disagree with the Standard Model by around 2sigma. In this case the key aspect of the Standard Model is the calculation of the decay constant, f_{D_s}, with lattice QCD. This…
The experimental predictions of $R_D$, $R_{D^*}$, $R_{J/\psi}$, $P_\tau^{D^*}$ and $F_L^{D^*}$ in $B$ decays mediated via $b\,\to\, c\, l\,\nu$ quark level transition deviate significantly from the standard model expectations. The current…
Recent experimental results for the ratio of the branching fractions of $\bar B \to D^{(*)}\tau \nu_\tau$ and $B\to D^{(*)} \mu \nu_\mu$ decays came as a surprise and lead to a discussion of possibility to constraining new physics through…
Including the recent preliminary results of BaBar and BELLE experiments, we update the currently allowed intervals for various CKM parameters: $\bar\rho$, $\bar\eta$, $\sin2\beta$, $\sin2\alpha$, $\sin^2\gamma$. We also update the SM…
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…
Recently, we developed a strategy to analyse the B -> pi pi,pi K data. We found that the B -> pi pi measurements can be accommodated in the Standard Model (SM) through large non-factorizable effects. On the other hand, our analysis of the…
We investigate the dimensional dependence (D-dependence) of the difference (gap) between the critical temperatures associated with the uniform/non-uniform and non-uniform/gapped transitions in the large-N bosonic gauge theories with D…
Flavour changing neutral current decays are a very sensitive test of the standard model and its extensions. In particular the decay K -> pi nu nubar constitutes a clean way to provide constraints, independent of long distance effects.…
Will further scaling up of machine learning models continue to bring success? A significant challenge in answering this question lies in understanding generalization gap, which is the impact of overfitting. Understanding generalization gap…
At Moriond 2019, Belle collaboration has announced new measurements on the flavour ratios $R_D - R_{D^*}$ which are consistent with their Standard Model predictions within $1.2\sigma$. After inclusion of these measurements, the global…
The decays B -> D^{**} pi, where D^{**} is a narrow p-wave charm resonance, are investigated in the context of a generalized factorization hypothesis, including the leading nonfactorizable corrections. The decay rates for these processes…