Related papers: Instantons and Nucleon Magnetism
We examine the contribution of small instantons to the axion mass in various UV completions of QCD. We show that the reason behind the potential dominance of such contributions is the non-trivial embedding of QCD into the UV theory. The…
The instanton--antiinstanton pair induced asymptotics of perturbation theory expansion for QCD correlators is considered. It is argued that though the true asymptotics is dominated by renormalon, the instanton-induced contribution may…
New QCD sum rules for nucleons in nuclear matter are derived from a mixed correlation function of spin-1/2 and spin-3/2 interpolating fields. These sum rules allow a determination of the scalar self-energy of the nucleon independent of the…
We calculate the electromagnetic pion form factor at intermediate space-like momentum transfer from the QCD sum rule for the correlation function of two {\it pseudoscalar } interpolating fields and the electromagnetic current. This…
QCD instantons generate non-perturbative spin- and flavor- dependent forces between quarks. We review the results of a series of studies on instanton-induced correlations in hadrons. We first present some evidence for instanton-mediated…
Instanton contributions to pseudoscalar finite-energy sum rules are extracted from the explicit single-instanton contribution to the pseudoscalar Laplace sum rule in the instanton liquid model.
In this article, we study the pentaquark state $ \Theta^+(1540)$ with a (scalar)diquark-(pseudoscalar)diquark-antiquark type interpolating current in the framework of the QCD sum rules approach by including the contributions from the direct…
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.…
We calculate the nucleon parameters in nuclear matter using the QCD sum rules method. The radiative corrections to the leading operator product expansion terms are included, with the corrections of the order \alpha_s beyond the logarithmic…
Interpolating fields, used to excite hadrons from the QCD vacuum in nonperturbative field-theoretic investigations of hadron properties, are explored with an emphasis on unconventional nucleon interpolators. The QCD continuum model for…
Octet baryon magnetic moments are calculated in framework of the light cone QCD sum rules. The analysis is carried for the general form of the interpolating currents for octet baryons. A comparison of our results on the magnetic moments of…
The short-time regime of QCD two-point correlation functions is examined through a QCD-Sum-Rule-inspired continuum model. QCD Sum Rule techniques are tested and alternate nucleon interpolating fields are discussed. The techniques presented…
The in-medium behavior of the nucleon spectral density including self-energies is revisited within the framework of QCD sum rules. Special emphasis is given to the density dependence of four-quark condensates. A complete catalog of…
Nucleon structure study is one of the most important research areas in modern physics and has challenged us for decades. Spin has played an essential role and often brought surprises and puzzles to the investigation of the nucleon structure…
The influence of nonperturbative fields on instantons in quantum chromodynamics is studied. Effective action for instanton is derived in bilocal approximation and it is demonstrated that stochastic background gluon fields are responsible…
We compute the effect of small-size instantons on the coefficient function of the chiral condensate in the operator product expansion of current-current correlators. Furthermore, we also compute the instanton corrections associated with…
We present an analysis of QCD sum rules for pion form factor in next-to-leading order of perturbation theory for the case of pseudoscalar pion currents. The essential instanton contribution is reanalysed with account for present more…
We compute the nucleon matrix elements of QCD operators of twist 3 and 4 in the instanton vacuum. We consider the operators determining 1/Q^2-power corrections to the Bjorken, Ellis-Jaffe and Gross-Llewellyn-Smith sum rules. The nucleon is…
This project aims to give indications to find monopole and instanton effects in QCD on the observables by experiments. First, we add the monopole and anti-monopole to the QCD vacuum of the quenched SU(3) and calculate the physical…
Using the light-cone sum rules at leading order, we present an approach to perform the preliminary upper estimation for the nucleon gravitational form factor $D(t)$ ($D$-term contribution). Comparison with the experimental data and with the…