Related papers: Small-Size Instanton Corrections to the $\tau$ Had…
Local duality estimates for the $\rho$-meson leptonic width and the spectrum of radial excitations are updated. New perturbative corrections are included in the analysis that gives good agreement with experimental data on low energy…
We study N=2 supersymmetric Abelian gauge model with the Fayet-Iliopoulos term and an arbitrary number of chiral matter multiplets in two dimensions. By analyzing the instanton contribution we compute the non-perturbative corrections to the…
We study solitons in the context of Sakai-Sugimoto-Witten holographic model of QCD. In the large 't Hooft coupling limit, flat space instantons give an approximate description of baryons. We provide an ansatz through deforming the BPST…
We report on some technical aspects of our calculation of alpha_s^4 corrections to R(s) and the semi-leptonic tau decay width [1-3]. We discuss the inner structure of the result as well as the issue of its correctness. We demonstrate…
We consider the impact of O(alpha^2) hadronic corrections to the energy spectrum of the decay electron in muon decay. We find that the correction can be described, within good approximation, by a linear function in the electron energy.…
We use a D-instanton or physical gauge approach to re-derive the heterotic string worldsheet instanton contribution to the superpotential in Calabi-Yau compactification. We derive an analogous formula for worldsheet instanton corrections to…
We calculate the $\alpha_s$ corrections to the form factors which parameterize the hadronic tensor relevant for inclusive semileptonic $B \rightarrow X \tau\bar\nu_{\tau}$ and $\Lambda_b \rightarrow X \tau\bar\nu_{\tau}$ decays. We apply…
This paper presents $\alpha_s$ corrections to the inclusive semitauonic $B \to X_c \tau \bar{\nu}_\tau$ decay width and leptonic invariant mass spectrum up to order $1/m_b^3$ in the heavy quark expansion. Analytical results with full…
The effects of instantons close to the cut-off is studied in four dimensional SU(2) gauge theory with higher order derivative terms in the action. It is found in the framework of the dilute instanton gas approximation that the convergence…
We investigate the non-perturbative contribution of instantons to current matching kernels used in the context of the large momentum effective theory (LaMET). We derive explicitly these contributions using first principle semi-classical…
We analyze tau lepton decay observables, namely moments of the hadronic spectral density in the finite energy interval (0,M_\tau), within finite order perturbation theory including \alpha_s^4 corrections. The start of asymptotic growth of…
The calculation of perturbative corrections to the spectral moments observable in hadronic $\tau$ decays is reconsidered. The exact order-$\alpha_s^3$ results and the resummation procedure of Le~Diberder and Pich are compared with a partial…
Point to point correlators of currents are computed in quenched QCD using a chiral lattice fermion action, the overlap action. I compare correlators made of exact quark propagators with correlators restricted to low (less than 500 MeV)…
We provide arguments for the existence of novel hereinafter called poly-instanton corrections to holomorphic couplings in four-dimensional N=1 supersymmetric string compactifications. After refining quantitatively the D-brane instanton…
The effective QCD charge extracted from $\tau$ decay is remarkably constant at small momenta, implying the near-conformal behavior of hadronic interactions at small momentum transfer. The correspondence of large-$N_C$ supergravity theory in…
We investigate the distribution of instanton sizes in the framework of a simplified model for ensembles of instantons. This model takes into account the non-diluteness of instantons. The infrared problem for the integration over instanton…
We briefly report on the contribution of QCD-instantons to the phenomenon of saturation in deep-inelastic scattering (DIS) at small Bjorken-x. The explicitly known instanton gauge field serves as a concrete realization of an underlying…
Instanton effects on the Euclidean correlation function of two Wilson loops at an angle $\theta$, relevant to soft high-energy dipole-dipole scattering, are calculated in the Instanton Liquid Model and compared with the existing lattice…
Power corrections to hadronic event shapes are estimated using a recently suggested relationship between perturbative and non-perturbative effects in QCD. The infrared cutoff dependence of perturbative calculations is related to…
In this contribution three-loop QCD corrections to current correlators are considered. The application of the large momentum procedure, which provides a systematic expansion in $(m^2/q^2)^n$, allows the computation of terms up to $n=6$ for…