相关论文: Explaining the $R_K$ and $R_{K^*}$ anomalies
Very compelling deviations in the recently observed lepton nonuniversality observables $\big (R_{D^{(*)}}, R_{K^{(*)}}, R_{J/\psi} \big )$ of semileptonic $B$ meson decays from their Standard Model predictions hint towards the presence of…
We build a set of new observables using closely related non-leptonic penguin-mediated $B_d$ and $B_s$ decays: ${\bar B}_{d,s}\to K^{*0}\bar{K}^{*0}$, ${\bar B}_{d,s}\to K^{0}\bar{K}^{0}$, ${\bar B}_{d,s}\to K^{0}\bar{K}^{*0}$ and ${\bar…
The measurements of $R_{K}$ and $R_K^{*}$ provide hints for the violation of lepton universality. However, it is generally difficult to explain the $R_{K^*}$ measurement in the low $q^2$ range, $0.045 \le q^2 \le 1.1$ GeV$^2$. Light…
The LHCb collaboration has recently reported a 2.5 $\sigma$ discrepancy with respect to the predicted value in a test of lepton universality in the ratio $R_{K^*}= \hbox{BR}(B \to K^* \mu^+ \mu^-) / \hbox{BR}(B \to K^* e^+ e^-)$. Coupled…
The most recent measurements of the observables $R_{D^{(*)}}$ are in tension with the Standard Model offering hints of New Physics in $b\rightarrow c \ell \bar{\nu}_{\ell}$ transitions. Motivated by these results, in this work we present an…
We propose a set of new optimized observables using penguin mediated $\bar{B}_d$ and $\bar{B}_s$ decays: ${\bar B}_{d,s} \to K^{*0} \bar{K}^{*0}$, ${\bar B}_{d,s} \to K^{0} \bar{K}^{0}$, ${\bar B}_{d,s} \to K^{0} \bar{K}^{*0}$ and ${\bar…
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…
A global fit to the recent B->K*mu+mu- data shows indications for a large new-physics contribution to the Wilson coefficient of the semi-leptonic vector operator. In this article we consider a simple Z'-boson model of 3-3-1 type that can…
The LHCb has measured the ratios of $B\to K^\ast\mu^+\mu^-$ to $B\to K^\ast e^+ e^-$ branching fractions in two dilepton invariant mass squared bins, which deviate from the Standard Model predictions by approximately $2.5\sigma$. These new…
Measurements of the ratio of $B \to K^* \mu \mu $ to $B \to K^* e e $ branching fractions, $R_{K^*}$, by the LHCb collaboration strengthen the hints from previous studies with pseudoscalar kaons, $R_K$, for the breakdown of lepton…
We present a global analysis of the B->K*(->K pi)mu+mu- decay using the recent LHCb measurements of the primary observables P_{1,2} and P'_{4,5,6,8}. Some of them exhibit large deviations with respect to the SM predictions. We explain the…
The $B\to K^*\mu\mu$ decay exhibits deviations with respect to Standard Model expectations and the measurement of the ratio $R_K$ hints at a violation of lepton-flavour universality in $B\to K\ell\ell$ transitions. Both effects can be…
Using 180 pb^-1 of data collected with the CDF II detector at the Tevatron, we measure the first two moments of the hadronic invariant mass-squared distribution in charmed semileptonic B decays. From these we determine the non-perturbative…
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…
Recently, the LHCb Collaboration provided updated measurements for the lepton flavour ratios $R_K$ and $R_{K^*}$. The currently observed values align with the predictions of the standard model. In light of these recent updates, our…
A recent LHCb measurement of the ratio $R_{K^*}$ of $B\to K^*\mu\bar\mu$ to $B\to K^*e\bar e$ branching fractions has produced results in mild tension with the standard model (SM). This adds to the known anomalies also induced by the $b\to…
We update the branching ratios for the inclusive decays $B\to X_s \ell^+ \ell^-$ and the exclusive decays $B\to (K,K^*) \ell^+ \ell^-$, with $\ell=e, \m$, in the standard model by including the explicit $O(\a_s)$ and $\Lambda_{\hbox{\tiny…
While the LHC did not observe direct evidence for physics beyond the standard model, indirect hints for new physics were uncovered in the flavour sector in the decays $B\to K^*\mu^+\mu^-$, $B\to K\mu^+\mu^-/B\to Ke^+e^-$,…
Rare semileptonic $b \to s \ell^+ \ell^-$ transitions provide some of the most promising frameworks to search for new physics effects. Recent analyses of these decays have indicated an anomalous behaviour in measurements of angular…
There are two sources that help to explain the $\text{R}_\text{K}$, $\text{R}_{\text{K}^*}$ anomalies in the MF331 model. The first is non-LFUV couplings of the new neutral gauge boson $\text{Z}^{\prime}$ with leptons,…