相关论文: Beyond $\mathcal{R}(D^{(*)})$ with the general 2HD…

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 possible transverse polarization of the $\tau$-lepton, which is $T$-odd and can be used to measure CP-violation, is estimated precisely in the radiative decay mode $B_c \to \tau \bar \nu_\tau \gamma$ with possible parameters for the…

In the past few years, several hints of lepton flavour universality (LFU) violation have emerged in the $b \to c \tau \bar\nu$ and $b \to s \ell^+ \ell^-$ data. Quite recently, the Belle Collaboration has reported the first measurement of…

The experimental values of the lepton-flavour-universality tests ${\cal R}(D)$ and ${\cal R}(D^*)$ show a tension of about $3.1\sigma$ with their Standard Model prediction. Motivated by this tension, we perform a fit of the $b\to c\tau\nu$…

We study the constraints of the generic two-Higgs-doublet model (2HDM) type-III and the impacts of the new Yukawa couplings. For comparisons, we revisit the analysis in the 2HDM type-II. To understand the influence of all involving free…

The $R(D^{(\ast)})$ anomalies observed in $B\to D^{(\ast)}\tau\nu$ decays have attracted much attention in recent years. In this paper, we study the $B\to D^{(\ast)}\tau\nu$, $\Lambda_b\to\Lambda_c\tau\nu$, $B_c\to…

The anomalies in the measurements of $R_D$ and $R_{D^*}$ continue to provide motivation for physics beyond the Standard Model. In this work, we assume the new physics Wilson coefficients to be complex and find their values by doing a global…

The meson decays $B\to D\tau\nu$ and $B\to D^* \tau \nu$ are sensitive probes of the $b\to c\tau\nu$ transition. In this work we present a complete framework to obtain the maximum information on the physics of $B\to D^{(*)}\tau\nu$ with…

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 consider the recent LHCb result for $B_c\to J/\psi \tau \nu$ in conjunction with the existing anomalies in $R(D)$ and $R(D^\star)$ within the framework of a right-handed current with enhanced couplings to the third generation. The model…

The reported combined excess of about 4$\sigma$, by BABAR, Belle and LHCb, in the measurements of R($D^{(*)}$) and Br(B $\rightarrow \tau \nu_{\tau}$) from that of the standard model expectation constitute the most significant discrepancy…

Motivated by renewed evidence for new physics in $b \to s\ell\ell$ transitions in the form of LHCb's new measurements of theoretically clean lepton-universality ratios and the purely leptonic $B_s\to\mu^+\mu^-$ decay, we quantify the…

We present allowed regions in the space of observables of certain non-leptonic B-meson decays that characterize these modes within the Standard Model. A future measurement of observables lying significantly outside of these regions would…

We revisit the status of the new-physics interpretations of the anomalies in semileptonic $B$ decays in light of the new data reported by Belle on the lepton-universality ratios $R_{D^{(*)}}$ using the semileptonic tag and on the…

Measurements of the branching fractions of the semileptonic decays $B\to D^{(*)}\tau\bar\nu_\tau$ and $B_c\to J/\psi\tau\bar\nu_\tau$ systematically exceed the Standard Model (SM) predictions, pointing to possible signals of new physics…

We analyze the recent experimental evidence for an excess of $\tau$-lepton production in several exclusive semileptonic $B$-meson decays in the context of two-Higgs-doublet models. These decay modes are sensitive to the exchange of charged…

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 discuss flavor-violating constraints and consequently possible charged Higgs boson phenomenology emerging from a four-zero Yukawa texture embedded within the Type-III 2-Higgs Doublet Model (2HDM-III). Firstly, we show in detail how we…

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…

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…