相关论文: Lepton Flavor Violation in B Decays?
The R_K measurement by LHCb suggests non-standard lepton non-universality (LNU) to occur in b -> s l+ l- transitions, with effects in muons rather than electrons. A number of other measurements of b -> s l+ l- transitions by LHCb and…
A recent proposal for explaining discrepancies in angular observables in the rare decay B --> K*mu+mu- with a gauged L_mu - L_tau current carried with it the prediction of lepton flavor universality violation in related B-meson decays. This…
LHCb has reported deviations from the Standard Model in $b\to s\mu^+\mu^-$ transitions for which a new neutral gauge boson is a prime candidate for an explanation. As this gauge boson has to couple in a flavour non-universal way to muons…
The LHCb collaboration has recently presented their result on R_K = BR(B+ -> K+ mu+ mu-)/ BR(B+ -> K+ e+ e-) for the dilepton invariant mass bin m_{ll}^2 = 1-6 GeV^2 (l = mu, e). The measurement shows an intriguing 2.6 sigma deviation from…
We interpret the recent hints for lepton flavor universality violation in rare $B$ meson decays. Based on a model-independent effective Hamiltonian approach, we determine regions of new physics parameter space that give a good description…
There are some slight tensions with the SM predictions within the latest LHCb measurements. Besides the known anomaly in one angular observable of the rare decay B -> K* mu+ mu-, another small discrepancy recently occurred. The ratio R_K =…
LHCb found hints for physics beyond the standard model in $B\to K^*\mu^+\mu^-$, $B\to K^*\mu^+\mu^-/B\to K^*e^+e^-$ and $B_s\to\phi\mu^+\mu^-$. In addition, the BABAR results for $B\to D^{(*)}\tau\nu$ and the CMS excess in…
We describe a possibility to explain the $2.6\sigma$ deviation from lepton flavour universality observed by the LHCb collaboration in $B^+\to K^+\ell^+\ell^-$ decays in the context of minimal composite Higgs models. We find that a sizable…
An overview of ATLAS and CMS studies of B_s leptonic decays providing constraints on the lepton flavour violation phenomenon is presented. Except direct lepton flavour violating final states B_s -> l_1^+ l_2^-, constraints can also be set…
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…
Motivated by the recent LHCb announcement of a $3.1\sigma$ violation of lepton-flavor universality in the ratio $R_K=\Gamma(B\to K\mu^+\mu^-)/\Gamma(B\to K e^+ e^-)$, we present an updated, comprehensive analysis of the flavor anomalies…
Motivated by the measurements of $b\to s\ell^+\ell^-$ transitions, including $R(K)$ and $R(K^*)$, we examine lepton flavour (universality) violation in $B$ decays and its connections to $\mu\to e\gamma$ in generic leptoquark models.…
Even though the LHC searches did not unveil the new physics particles so far, LHCb hints towards deviations from lepton flavor universality in exclusive decays based on the transition $b\to s\ell\ell$. In this proceeding, we present a new…
We analyse the violations of lepton-flavour universality in the ratios B(P -> l nu)/B(P -> l' nu) using a general effective theory approach, discussing various flavour-symmetry breaking patterns of physics beyond the SM. We find that in…
The latest measurements of rare $b\to s$ decays in the LHCb experiment have led to results in tension with the predictions of the standard model (SM), including a tentative indication of the violation of lepton flavor universality. Assuming…
Recent results from Super Kamiokande suggest $\nu_\mu-\nu_\tau$ mixing and hence lepton flavor violation. In supersymmetric models, this flavor violation may have implications for the pattern of slepton masses and mixings. Possible signals…
Present measurements of b->c tau nu and b->u tau nu transitions differ from the standard model predictions of lepton flavor universality by almost 4sigma. We examine new physics interpretations of this anomaly. An effective field theory…
We have searched for lepton flavor violating semileptonic tau decays using a data sample of 153.8/fb accumulated with the Belle detector at the KEKB e+e- collider. For the six decay modes studied, the observed yield is compatible with the…
Several experiments observed deviations from the Standard Model (SM) in the flavour sector: LHCb found a $4-5\,\sigma$ discrepancy compared to the SM in $b\to s\mu^+\mu^-$ transitions (recently supported by an Belle analysis) and CMS…
We study the lepton-flavor-violating reaction $\mu^+ e^- \to e^+ e^-$ within two extensions of the standard model that include heavy neutrinos. The reaction is studied in the low energy limit in the form of muonium decay $M\to e^+ e^-$ and…