相关论文: Test of lepton universality and searches for lepto…

Lepton flavor universality can be tested through the ratio of semileptonic $B$ meson decays and leptonic $\Upsilon$ meson decays, with $\Upsilon \equiv \Upsilon(nS)$ ($n=1,2,3$). For the charged-current transitions $b \to…

Charged lepton-flavor violating processes are extremely rare in the Standard Model, but they may occur in several beyond-the-Standard Model theories, including Supersymmetry or models with leptoquarks or compositeness. We present a search…

Charged lepton flavour violating processes are unobservable in the standard model, but they are predicted to be enhanced in several new physics extensions. We present the results of a search for $\Upsilon (2S)$ and $\Upsilon (3S)$ decays to…

Searches for lepton-flavor-violating decay of a tau lepton to a lighter mass lepton and a photon have been performed with the entire dataset of (963 +- 7) x 10^6 tau decays collected by the BaBar detector near the Upsilon(4S), Upsilon(3S)…

Using a sample of 122 million Upsilon(3S) decays collected with the BaBar detector at the PEP-II asymmetric energy collider at the SLAC National Accelerator Laboratory, we measure the ratio…

The ratio $R_{\tau\mu}(\Upsilon(1S)) = \Gamma_{\Upsilon(1S)\to\tau^+\tau^-}/\Gamma_{\Upsilon(1S)\to\mu^+\mu^-}$ is measured using a sample of $(121.8\pm1.2)\times10^6$ $\Upsilon(3S)$ events recorded by the BABAR detector. This measurement…

Several measurements on $R_D, R_{D^*}$, and $R_{J/ \psi}$ by the BaBar, Belle, and LHCb experiments show significant deviations from their Standard Model (SM) predictions, which illustrate the fact that the concept of lepton flavor…

We present recent results concerning the searches for light Higgs-like particles in the decay $\Upsilon (3S) \to \gamma A^{0}, A^{0}\to \mu^{+}\mu^{-}$ as well as for the lepton flavour violation in the decays $\Upsilon (3S) \to…

Charged lepton flavor violating processes are unobservable in the standard model, but they are predicted to be enhanced in several extensions to the standard model, including supersymmetry and models with leptoquarks or compositeness. We…

We propose a novel method to probe the persistent hints of Lepton Flavour Universality violation observed in semileptonic $B$ decays. Relying on the specific properties of the Belle II experiment, it consists in comparing the inclusive…

Searches for lepton flavor violating tau -> l gamma, tau -> lll and tau -> lhh decays at the BaBar experiment are presented. Upper limits on the branching ratios are obtained at the level of 10^{-7} at 90% confidence level.

We report on the first search for electron-muon lepton flavor violation (LFV) in the decay of a $b$~quark and $b$~antiquark bound state. We look for the LFV decay $\Upsilon (3S)\rightarrow e^{\pm}\mu^{\mp}$ in a sample of 118~million…

We have searched for lepton flavor violating decays of a $\tau$ to a lighter-mass charged lepton and an $\omega$ vector mesonusing 384.1 $fb^{-}$ of $e^+e^- $ annihilation data collected with the BABAR detector at the Stanford Linear…

A search for lepton flavor violating decays of the $\tau$ lepton to a lighter mass lepton and a pseudoscalar meson has been performed using 339 fb$^{-1}$ of $e^+e^-$ annihilation data collected at a center-of-mass energy near 10.58 GeV by…

Very recently the LHCb experiment released the first measurement of the ratio $R(\Lambda_c) = {\rm BR}(\Lambda_b \to \Lambda_c\tau\bar{\nu}_\tau)/{\rm BR}(\Lambda_b \to \Lambda_c\mu\bar{\nu}_\mu)$. Moreover, the BABAR experiment reported a…

Considering the constraints from the experimental data on $\mu\rightarrow e\gamma$, $\mu\rightarrow3e$, $\mu-e$ conversion etc., we analyze the Lepton Flavor Violating decays $\phi(J/\Psi,\Upsilon(1S)) \rightarrow e^+\mu^-(\mu^+\tau^-)$ in…

We present a search for the charged lepton-flavor-violating decays $\Upsilon(1S)\rightarrow\ell\ell^\prime$ and radiative charged lepton-flavour-violating decays $\Upsilon(1S)\rightarrow\gamma\ell\ell^\prime$ [$\ell,\ell^\prime = e, \mu,…

In this paper we present two searches for new physics in Upsilon(3S) decays collected by the BABAR detector. We search for charged lepton-flavour violating decays of the Upsilon(3S), which are unobservable in the Standard Model but are…

We present searches for the leptonic decays B+ -> l+ nu and the lepton flavor violating decays B0 -> l+ tau-, where l=e,mu, with data collected by the BaBar experiment at SLAC. This search demonstrates a novel technique in which we fully…

I present two analyses done with the CLEOIII detector at CESR. The first is a search for the Lepton Flavor Violating decay Upsilon to mu tau, with preliminary results, and the second constrains Lepton Universality in Upsilon to tau tau…