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It is shown that the quark-gluon interaction induced by instantons leads to the quark anomalous chromomagnetic moment. In the instanton-liquid model for the QCD vacuum, the chromomagnetic moment is $\mu_a=-\frac{\pi f}{2\alpha_s}$, where f…

High Energy Physics - Phenomenology · Physics 2009-10-30 N. I. Kochelev

In this review we will concentrate on the nonperturbative effects in the properties of hadrons made from the light-heavy and heavy-heavy quarks in the framework of Instanton Liquid Model (ILM) of QCD vacuum. We briefly discuss the main…

High Energy Physics - Phenomenology · Physics 2022-01-26 M. Musakhanov , U. Yakhshiev

We study isospin breaking instanton corrections to the operator product expansion of the nucleon correlation functions. After a comparison with quark model calculations based on the 't Hooft interaction, we examine the role of instantons in…

High Energy Physics - Phenomenology · Physics 2014-11-17 Hilmar Forkel , Marina Nielsen

We performed the measurement of the inclusive electron scattering off the proton in the resonance region (W<2.5 GeV) at momentum transfer Q2 below 4.5 (GeV/c)^2 with the CLAS detector. The large acceptance of CLAS provided an access to a…

High Energy Physics - Phenomenology · Physics 2007-05-23 M. Osipenko , S. Simula , G. Ricco , G. Fedotov , E. Golovach , B. Ishkhanov , E. Isupov , V. Mokeev

New Results on the measurement of the proton structure function F_2(x,Q^2) are reported for momentum transfers squared Q^2 >= 1.5 GeV^2 and Bjorken x >= 3.5 10^{-5} using data collected by the HERA experiments H1 and ZEUS in 1994. F_2…

High Energy Physics - Experiment · Physics 2007-05-23 Gregorio Bernardi

An enhancement for the $\eta$ production in proton-neutron collisions as compared with that in proton-proton scattering has been recently observed. We present a calculation for the production cross section, in proton-neutron collisions near…

High Energy Physics - Phenomenology · Physics 2009-10-31 N. I. Kochelev , V. Vento , A. V. Vinnikov

It is shown, that the hard component of quarks distribution functions induced by instantons gives the essential contribution to hard diffractive processes. We predict large polarization effects in these processes.

High Energy Physics - Phenomenology · Physics 2009-09-25 N. I. Kochelev

A simple model for the instanton ensemble at finite temperature T is proposed, including ``random" and strongly correlated ``molecular" component. T-dependence of fermionic zero modes naturally leads to chiral symmetry restoration, without…

High Energy Physics - Phenomenology · Physics 2009-10-28 E. -M. Ilgenfritz , E. V. Shuryak

This work is devoted to the study of the non-perturbative contributions in non-leptonic hyperon decays. We show that the instanton-induced 't Hooft interaction can naturally explain the Delta I=1/2 rule, by generating quark-diquark…

High Energy Physics - Phenomenology · Physics 2009-11-10 M. Cristoforetti , P. Faccioli , E. V. Shuryak , M. Traini

New results from the H1 and ZEUS collaborations on the measurement of cross-sections at very high Q^2 (up to 25000 GeV^2) and on the proton structure function F_2(x,Q^2) for momentum transfers squared Q^2 >= 1.5 GeV^2 and Bjorken x >= 3.5…

High Energy Physics - Experiment · Physics 2007-05-23 Gregorio Bernardi

Phenomenological aspects of chirality violating processes induced by QCD instantons in deep inelastic scattering are discussed. First instanton searches and the prospects for their experimental discovery at HERA are presented.

High Energy Physics - Phenomenology · Physics 2009-09-25 Michael Kuhlen

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.

High Energy Physics - Phenomenology · Physics 2009-11-07 N. I. Kochelev , V. Vento

We study the effects of instantons on the charged pion electro-magnetic formfactor at intermediate momenta. In the Single Instanton Approximation (SIA), we predict the pion formfactor in the kinematic region Q^2=2-15 GeV^2. By developing…

High Energy Physics - Phenomenology · Physics 2009-11-07 P. Faccioli , A. Schwenk , E. V. Shuryak

Instanton calculations in QCD are generically plagued by infrared divergencies associated with the integration over the instanton size $\rho$. Here, we demonstrate explicitly that the typical inverse hard momentum scale ${\mathcal Q}^{-1}$…

High Energy Physics - Phenomenology · Physics 2016-09-06 S. Moch , A. Ringwald , F. Schrempp

The analysis of nonperturbative effects in high energy asymptotics of the electomagnetic quark form factor is presented. It is shown that the nonperturbative effects determine the initial value for the perturbative evolution of the quark…

High Energy Physics - Phenomenology · Physics 2009-11-10 Igor O. Cherednikov

Measurements of proton structure functions made in neutral and charged current interactions at HERA are discussed, covering four-momentum transfers Q^2 from about 0.5 GeV^2 to 30000 GeV^2. The results include the rise of the structure…

High Energy Physics - Experiment · Physics 2017-08-23 Joerg Gayler

The strangeness contribution to the vector and axial form factors of the proton is presented for momentum transfers in the range 0.45 < $Q^2$ < 1.0 GeV$^2$. The results are obtained via a combined analysis of forward-scattering…

High Energy Physics - Experiment · Physics 2014-11-17 Stephen Pate

In a first part, I review our detailed investigation of the prospects to discover deep-inelastic processes induced by small QCD-instantons at HERA. This includes the essence of our calculations based on instanton-perturbation theory,…

High Energy Physics - Phenomenology · Physics 2008-11-26 F. Schrempp

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…

High Energy Physics - Phenomenology · Physics 2009-11-11 A. Brandenburg , A. Ringwald , A. Utermann

In this paper, the proton structure function $F_2 ^p (x,Q^2)$ at small-$x$ is investigated using an analytical solution of the Balitsky-Kovchegov (BK) equation. In the context of the color dipole description of deep inelastic scattering…

High Energy Physics - Phenomenology · Physics 2024-03-21 Ranjan Saikia , Pragyan Phukan , Jayanta Kumar Sarma