Related papers: Lepton universality test with Kl2 decays at NA62 e…

The LHCb Collaboration's measurement of R_K = B(B+ -> K+ mu+ mu-)/B(B+ -> K+ e+e-) lies 2.6 sigma below the Standard Model prediction. Several groups suggest this deficit to result from new lepton non-universal interactions of muons. But…

Decay rate, forward-backward asymmetry and polarization asymmetries of final state leptons in B-> K_{1}tau ^{+}tau ^{-}, where K_{1} is the axial vector meson, are calculated in Standard Model and in the universal extra dimension (UED)…

The leptonic $\tau$ decays are calculated at the 1-loop level in the Minimal Supersymmetric Standard Model. The deviation from the $\tau - \mu - e$ universality is studied as a function of the supersymmetric parameters and discussed in the…

Using $e^+e^-$ annihilation data of $2.93~\mathrm{fb}^{-1}$ collected at center-of-mass energy $\sqrt{s}=3.773$ GeV with the BESIII detector, we measure the absolute branching fraction of $D^{0}\to K^{-}\mu^{+}\nu_{\mu}$ with significantly…

The $K\to\pi\nu\bar{\nu}$ ultra-rare decays are precisely computed in the Standard Model (SM) and are ideal probes for physics beyond the SM. The NA62 experiment at the CERN SPS is designed to measure the charged channel with a precision of…

We present the first comprehensive tests of light-lepton universality in the angular distributions of semileptonic $B^0$-meson decays to charged spin-1 charmed mesons. We measure five angular-asymmetry observables as functions of the decay…

The ultra-rare decay $K^+\to\pi^+\nu\bar\nu$ is a golden mode in flavor physics. The Standard Model prediction for its branching ratio is below $10^{-10}$. This decay mode is highly sensitive to new physics models at mass scales up to…

The NA48/2 experiment at CERN collected a large sample of charged kaon decays into final states with multiple charged particles in 2003--2004. A new upper limit on the rate of the lepton number violating decay $K^{\pm} \to \pi^{\mp}…

In this work we study the potential of the lepton flavor ratios $R_{K}^{\tau \mu} \equiv \Gamma(B \to K \tau^+ \tau^-)/ \Gamma(B \to K \mu^+ \mu^-)$ and $ R_{K^{*}}^{\tau \mu} \equiv \Gamma(B \to K^* \tau^+ \tau^-)/ \Gamma(B \to K^* \mu^+…

We present a global analysis of leptonic and semileptonic kaon decays data, including all recent results by BNL-E865, KLOE, KTeV, ISTRA+, and NA48. Experimental results are critically reviewed and combined, taking into account theoretical…

We present the analysis technique and preliminary results of two ongoing analyses at CLEO which put lepton universality and lepton flavor conservation to the test in Upsilon decays.

The Standard Model of particle physics encapsulates our current best understanding of physics at the smallest scales. A fundamental axiom of this theory is the universality of the couplings of the different generations of leptons to the…

We report the first measurement of the semileptonic decay $D^+_s \rightarrow K^*(892)^0\mu^+\nu_{\mu}$ and an improved measurement of the decay $D^+_s \rightarrow K^*(892)^0 e^+\nu_{e}$ using a sample of $7.33~\mathrm{fb}^{-1}$ of $e^+e^-$…

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…

Recently hints of lepton flavor non-universality emerged in the BaBar and LHCb experiments. In this paper we propose tests of lepton universality in $\nu_{\tau}$ scattering. To parametrize the new physics we adopt an effective Lagrangian…

The NA48/2 experiment at CERN collected a large sample of charged kaon decays into final states with multiple charged particles in 2003--2004. A new upper limit on the rate of the lepton number violating decay…

High precision electroweak tests, such as deviations from the Standard Model expectations of the Lepton Flavor Universality breaking in K->lnu (with l= e or mu), represent a powerful tool to test the Standard Model and, hence, to constrain…

We report measurements of the ratios of branching fractions ${\cal R}(D^{(*)+}) = \frac{{\cal B}(\overline{B}{}^0 \to D^{(*)+} \,\tau^- \, \overline{\nu}_\tau)}{{\cal B}(\overline{B}{}^0 \to D^{(*)+} \, \ell^- \, \overline{\nu}_\ell)}$,…

In this report I will present the recent results on K mesons from the KLOE experiment at the DAFNE e+e- collider working at the center of mass energy ~1GeV ~m_{phi}. They include V_{us} determinations, the test on the unitarity of the first…

Kaon physics can test new-physics effects in leptonic or semileptonic decays. A unitarity test of the first row of the CKM mixing matrix is obtained from the precision measurements of Kl3 widths for K{\pm}, KL, and (unique to KLOE) KS. The…