Related papers: Testing QCD with Hypothetical Tau Leptons
This article reviews and updates the Standard Model prediction of the tau lepton g-2. Updated QED and electroweak contributions are presented, together with new values of the leading-order hadronic term, based on the recent low energy e+ e-…
The results of evaluation of mixed QED X QCD corrections to R(s) in e^+e^- annihilation and R_{\tau} in hadronic decay of the \tau lepton to O(\alpha^n\alpha_s^m), m+n \leq 3, are presented. The net effect on \alpha_s(M_Z) from the Z decay…
In the light of recent muon (g-2) result by the E821 experiment at BNL, the importance of and interest in the total hadronic cross sections in e+ e- collisions and R(e+ e- --> hadrons) have been heightened. We report on the integrated data…
A new algorithm is presented to discriminate reconstructed hadronic decays of tau leptons ($\tau_\mathrm{h}$) that originate from genuine tau leptons in the CMS detector against $\tau_\mathrm{h}$ candidates that originate from quark or…
Semileptonic exclusive tau decays in the Standard Model are reviewed. As it is well-known, they are a privileged arena to learn about low-energy hadronization. They also allow for a number of clean new physics tests, which have attracted…
We review the Standard Model prediction of the tau lepton g-2 presenting updated QED and electroweak contributions, as well as recent determinations of the leading-order hadronic term, based on the low energy e+e- data, and of the hadronic…
The $\tau$ decay rate into hadrons of invariant mass smaller than $\sqrt{s_0}\gg\Lambda_{\rm QCD}$ can be calculated in QCD assuming global quark--hadron duality. It is shown that this assumption holds for $s_0>0.7$~GeV$^2$. From…
Modern-day `testing' of (perturbative) QCD is as much about pushing the boundaries of its applicability as about the verification that QCD is the correct theory of hadronic physics. This talk gives a brief discussion of a small selection of…
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 reconstruction of tau-pair production, $e^{+}e^{-} \to \tau^{+}\tau^{-}$, from the subsequent 3-prong ($\tau^{+} \rightarrow \pi^{+} \pi^{-} \pi^{+} \bar{\nu}_{\tau}$) and 1-prong ($\tau^{-} \to \ell^{-} \bar{\nu}_{\ell} \nu_{\tau}$,…
I describe the current status of tests of perturbative QCD, using measurements of jet, photon, weak boson and heavy flavor production from the Tevatron, LEP and HERA. Measurements of the strong coupling constant are described, and I…
Hadronic $\tau$ decays provide a clean laboratory for the precise study of quantum chromodynamics (QCD). Observables based on the spectral functions of hadronic $\tau$ decays can be related to QCD quark-level calculations to determine…
The most general Lorentz invariant spin-correlation functions for $\tau ^{-}\rightarrow \rho ^{-}\nu ,a_1^{-}\nu ,K^{*-}\nu , \pi ^{-}\nu ,K^{-}\nu $ are expressed in terms of eight semi-leptonic parameters. They are physically defined in…
We present a search for the decay B+ -->tau+ nu using 467.8 x 10^6 B B pairs collected at the Y(4S) resonance with the BaBar detector at the SLAC PEP-II B-Factory. We select a sample of events with one completely reconstructed B- in the…
By expanding functions of parton fragmentation into a heavy hadron in the inverse of the heavy quark mass $m_Q$ we attempt to factorize them into perturbative- and nonperturbative parts. In our approach the nonperturbative parts can be…
In this article, we propose a novel approach to measure the branching ratios of the leptonic eta(')-> mu+mu- decays by using charmed meson decays, namely, D+(s)->pi+ eta(')(->mu+mu-) and D0->K-pi+eta(')(->mu+mu-). We advocate that the data…
We discuss the implications of charged lepton energy cut to the hadronic invariant mass spectrum in charmless semileptonic B decays. Charged-lepton energy cut is inevitable in order to remove secondary leptonic events such as b -> c, tau ->…
Searches for a Heavy Sterile Neutrino $N$ profit from precise predictions of inclusive decay rates, entering predictions for branching fractions and lifetime. Once decay channels into semi-hadronic final states are open, a reliable…
Based on the flavor structure of four-quark effective operators, we develop an automatic computation program to calculate hadronic two-body $B$ meson decay amplitudes, and apply it to their global analysis in the perturbative QCD (PQCD)…
In the literature it is assumed that the parton to hadron fragmentation function cannot be studied by using the lattice QCD method because of the sum over the (unobserved) outgoing hadronic states. However, in this paper we find that since…