Related papers: Direct Instanton Effects in Current-Current Correl…
The role of the QCD vacuum effects in high energy diffractive quark-quark and quark-antiquark scattering is studied with the Instanton Liquid Model. The special attention is given to the problem of formation of the soft Pomeron. We show…
In this talk, we describe part of a recent work on the correlation function of a V-A current with a V+A current in the framework of QCD in the limit of a large number of colours Nc. The discussion takes place within two successive…
This study investigates the effects on the connected and disconnected correlations for the scalar density that are induced by created monopoles and instantons in the QCD vacuum. To reveal the effects, we add a monopole and anti-monopole…
We investigate the chiral restoration at finite temperature $(T)$ under the strong external magnetic field $\vec{B}=B_{0}\hat{z}$ of the SU(2) light-flavor QCD matter. We employ the instanton-liquid QCD vacuum configuration accompanied with…
A chiral fermion action allows one to do very clean studies of chiral symmetry breaking in QCD. I will briefly describe how to compute with the overlap action (relatively) cheaply, and then turn to physics: Low modes of the Dirac operator…
We study the interplay between the <A^2> condensate and instantons in non-Abelian gauge theory. Therefore we use the formalism of Local Composite Operators, with which the vacuum expectation value of this condensate can be analytically…
The multi-instanton solutions by 'tHooft and Jackiw, Nohl & Rebbi are generalized to curvilinear coordinates. Expressions can be notably simplified by the appropriate gauge transformation. This generates the compensating addition to the…
Using quenched chiral perturbation theory, we compute the long-distance behaviour of two-point functions of flavour non-singlet axial and vector currents in a finite volume, for small quark masses, and at a fixed gauge-field topology. We…
We study the topological and fermionic vacuum structure of four-dimensional QCD on the lattice by means of correlators of fermionic observables and topological densities. We show the existence of strong local correlations between the…
The impact of QCD instantons on scalar glueball properties is studied in the framework of an instanton-improved operator product expansion (IOPE) for the 0^{++} glueball correlation function. Direct instanton contributions are found to…
We derive the Operator Product Expansion whose vacuum expectation value gives the time-moments of the pseudoscalar heavy-light current-current correlator up to and including terms in $\alpha_s^2$ multiplying…
Baryonic correlation functions are calculated within an effective chiral quark model motivated by the instanton liquid model of QCD. Using a flavour SU(3) symmetry for the local four-quark interaction and taking rotational zero modes for…
We aim to show the effects of the magnetic monopoles and instantons in quantum chromodynamics (QCD) on observables; therefore, we introduce a monopole and anti-monopole pair in the QCD vacuum of a quenched SU(3) by applying the monopole…
We derive a QCD sum rule for the flavour-singlet axial coupling constant $g_A^{(0)}$ from a two point correlation function of flavour-singlet axial vector currents in a one-nucleon state. In evaluating the correlation function by an…
We calculate the coefficients of operators with dimensions d <= 7 in the operator product expansion of correlators of q Gamma Q currents, for the effective field theory of an infinite-mass quark, Q. Exact two-loop results are obtained, with…
The instanton induced interaction leads to a significant enhancement of the $A_0$ weak amplitude determining the $\Delta I=1/2$ rule, through the contribution of operators with dimension d=9, as we show in the weak $K\to \pi\pi$ decay.
We present a simple set of power counting rules which allows us to easily estimate calculable instanton effects up to $O(1)$ factors. We apply the resulting Instanton NDA to examine the effects of small instantons on various axion models.…
The scalar susceptibility (chi_s) of QCD, which represents the response of the chiral condensate to a small perturbation of explicit chiral-symmetry breaking, is investigated within the nonlocal chiral quark model (NLchiQM) based on the…
This is the first of a series of papers devoted to a systematic study of QCD correlation functions in a framework of 'instanton vacuum' models. The topic of this paper is to work out approximate formulae for quark propagators in a…
We study the large N expansion of the partition function of the quiver superconformal Chern-Simons theories deformed by two continuous parameters which correspond to the general R-charge assignment to the matter fields. Though the…