Related papers: Leptons and QCD
Results on semi-hadronic decays of the $\tau$ lepton are presented, from studies of $e^+e^-$ annihilation data obtained at the Cornell Electron Storage Ring with the CLEO-II detector. Branching fractions have been measured for decays to…
The ratios among the leading-order (LO) hadronic vacuum polarization (HVP) contributions to the anomalous magnetic moments of electron, muon and tau-lepton, $a_{\ell=e,\mu \tau}^{HVP,LO}$, are computed using lattice QCD+QED simulations. The…
The anomalous magnetic moment of the muon, a_mu, has been measured with an overall precision of 540 ppb by the E821 experiment at BNL. Since the publication of this result in 2004 there has been a persistent tension of 3.5 standard…
Fits to the ARGUS data on hadronic decays of the tau-lepton, which determine the vector and axial-vector spectral functions, are used in order to determine the size of a dimension $d=2$ term in the Operator Product Expansion. Constraints…
Tau leptons play a crucial role in studies of the Higgs boson and searches for Beyond the Standard Model physics at the present LHC and in its high luminosity upgrade. This talk presents the latest advancements in the reconstruction and…
We derive precise standard model predictions for the dilepton invariant mass and the tau energy distributions in inclusive B -> Xc tau nu decay. We include Lambda_QCD^2/m_b^2 and alpha_s corrections using the 1S short-distance mass scheme,…
Hadronically decaying tau leptons are of prime importance in numerous physics analyses in ATLAS. The spectrum of the possible applications of hadronically decaying tau leptons reaches from Standard Model measurements, including Higgs…
The `XIIIth Quark Confinement and the Hadron Spectrum' conference (Confinement 2018) contained a `Round Table Discussion' on the status of the determinations of the strong coupling $\alpha_s(m_Z)$ as well as prospects for future…
Resummation of large QCD radiative corrections, including leading and next-to-leading logarithms, in pion electromagnetic form factor is reviewed. Similar formalism is applied to exclusive processes involving heavy mesons, and leads to…
The QED processes e^+ e^- -> e^+ e^- \mu^+ \mu^- and e^+ e^- -> e^+ e^- \tau^+ \tau^- are studied with the L3 detector at LEP using an untagged data sample collected at centre-of-mass energies 161 GeV < sqrt{s} < 209 GeV. The tau-pairs are…
We update our Standard Model predictions for g-2 of the muon and for the hadronic contributions to the running of the QED coupling, Delta alpha_had^(5)(M_Z^2). Particular emphasis is put on recent changes in the hadronic contributions from…
Analytical calculation is presented of the QCD radiative corrections to the rate of the process $b\to c\tau\bar\nu_\tau$ and to the $\tau$ lepton longitudinal polarization in $\tau\bar\nu_\tau$ rest frame. The results are given in the form…
The exclusive and semi-exclusive branching ratios of the tau lepton hadronic decay modes (h- v_t, h- pi0 v_t, h- pi0 pi0 v_t, h- \geq 2pi0 v_t, h- \geq 3pi0 v_t, 2h- h+ v_t, 2h- h+ pi0 v_t, 2h- h+ \geq 2pi0 v_t, 3h- 2h+ v_t and 3h- 2h+ \geq…
Two-loop electroweak corrections to the electron, muon, and tau lepton anomalous magnetic moments have been computed recently. Effects of hadronic contributions to the photon propagator in two-loop QED corrections have also been reanalysed.…
This talk discusses possible new physics interpretations of recent experimental results on the B-->K*mu+mu- decay that show a discrepancy with the Standard Model predictions. A model independent analysis that takes into account all the…
A non-perturbative expansion method which gives a well-defined analytic continuation of the running coupling constant from the spacelike to the timelike region is applied to the inclusive semileptonic decay of the $\tau$--lepton. The method…
Anomalies from the LHCb lepton flavour universality and Fermilab muon anomalous magnetic momentum, show tantalizing hints of possible new physics from the lepton sectors. Due to its large mass and shorter lifetime than muon, the tau lepton…
Neutral-current semileptonic $B$ decays are plagued by hadronic resonances across the dilepton invariant-mass squared spectrum, $q^2$. For light leptons, $\ell=e,\mu$, these resonances can be avoided with suitable $q^2$ cuts. This strategy…
In this paper we show that the excess of the tau tau events with respect to the Standard Model background predictions, observed by the ATLAS and CMS collaborations and interpreted as the evidence of the Higgs-boson decay into a pair of…
The recent results in QCD at low energies are reported. The theoretical analysis of hadronic tau-decay is performed in complex q^2-plane. The terms of perturbation theory (PT) up to alpha^3_s are accounted, the terms of operator product…