Related papers: Small-Size Instanton Corrections to the $\tau$ Had…
We study the flavor universality of the lepton couplings with the W and Z bosons. Currently, it is constrained by the electroweak precision observables. We focus on the leptonic decay of the pion. It is shown that the decay is expected to…
The momenta of $\tau$ decay products in the reaction $e^+e^-\to\tau^+\tau^-$ do not constrain the $\tau$ direction unambiguously. It is shown how the measurement of tracks of hadrons from semileptonic $\tau$ decays, in particular their…
We study the effects of superconducting pairing in small metallic grains. We show that in the limit of large Thouless conductance one can explicitly determine the low energy spectrum of the problem as an expansion in the inverse number of…
Exclusive semi-leptonic decays of the tau lepton offer a clean probe to study the hadronization of QCD currents in its non-perturbative regime and learn about resonance dynamics, which drives strong interactions in these processes. In this…
We apply analytic perturbation theory to the inclusive decay of a $\tau$ lepton into hadrons. It is shown that the resulting analyticity of the coupling constant strongly influences the value of the QCD $\Lambda$-parameter extracted from…
We have extended our program of QCD simulations with an improved Kogut-Susskind quark action to a smaller lattice spacing, approximately 0.09 fm. Also, the simulations with a approximately 0.12 fm have been extended to smaller quark masses.…
We review the radiative corrections to the $\tau \to P (P) \nu_\tau [\gamma]$ decays and their implications for several SM tests: lepton universality, CKM unitarity and non-standard interactions.
We study the role of small-size instantons in the determination of the topological susceptibility of the 2-d $O(3) \: \sigma $ model on the lattice. In particular, we analyze how they affect the non-perturbative determination, by Monte…
The perturbative quark-mass corrections to the $\tau$ hadronic width are analysed to $O(\alpha_s^3 m_q^2)$, using the presently available theoretical information. The behaviour of the perturbative series is investigated in order to assess…
The first calculation of the next-to-leading-order electroweak corrections to Z-boson + jet hadroproduction including leptonic Z-boson decays is presented, i.e. to the production of a charged lepton--anti-lepton final state in association…
In the present paper, the phenomenological model developed by the authors in previous papers has been used to evaluate the degradation induced by hadron irradiation at the future accelerator facilities or by cosmic protons in high…
The explicit multi-instanton solutions by 'tHooft and Jackiw, Nohl & Rebbi are generalized to curvilinear coordinates. The idea is that a gauge transformation can notably simplify the expressions obtained after the change of variables. The…
In this paper, we will analyze the short distance corrections to low energy scattering. They are produced because of an intrinsic extended structure of the background geometry of spacetime. It will be observed that the deformation produced…
We report measurements of the first and second moments of the hadronic invariant mass squared distribution, <M^2_X> and <(M^2_X-<M^2_X>)^2>, in B -> X_c l nu decays for minimum lepton momenta ranging from 0.7 to 1.5 GeV/c in the B meson…
We study instanton effects on inclusive semileptonic $b \rightarrow u$ decay using the heavy quark effective field theory and the operator product expansion. The effect contributes not only to the hadronic matrix element but also to the…
Nonperturbative corrections up to $m_b^{-2}$ to the heavy lepton energy distributions are investigated in the inclusive semileptonic weak decays of heavy flavors in QCD. In the case of $B$-meson decays, for $b \ra u\tau\bnu$ transitions…
This paper presents measurements of the leptonic asymmetries in Z0 decays measured with the SLD detector. Using a data sample of approximately 500,000 Z0 bosons, we report preliminary values for A_e, A_mu and A_tau using both hadronic and…
We study instanton contributions to hadronic decays of the scalar glueball, the pseudoscalar charmonium state $\eta_c$, and the scalar charmonium state $\chi_c$. Hadronic decays of the $\eta_c$ are of particular interest. The three main…
We consider QCD instanton-induced contributions to lepton pair production in hadron-hadron collisions. We relate these contributions to those known from deep inelastic scattering and demonstrate that they can be calculated reliably for…
We compute the decay rate for the process $\eta_c\to p\bar p$ using an effective helicity-flipping proton-antiproton-gluon vertex which incorporates nonperturbative chiral symmetry breaking effects induced by instantons. We fix the strength…