Related papers: Bounds on QCD Instantons from HERA
Diffractive processes in photon-proton interactions at HERA offer the opportunity to improve the understanding of the transition between the soft, non-perturbative regime in hadronic interactions at $Q^2 = 0$ and the perturbative region at…
In this paper we study the statistical mechanics of the instanton liquid in QCD. After introducing the partition function as well as the gauge field and quark induced interactions between instantons we describe a method to calculate the…
QCD point-to-point correlation functions at distances .2-1 fm are very different for different channels, and they tell us a lot about inter-quark interactions. Recent studies based on experimental data, 'instanton liquid' approach and…
Deep inelastic electron proton scattering at HERA II will allow precise studies of QCD and stringent tests of physics beyond the standard model. We discuss these two aspects of DIS with emphasis on the regime of high gluon densities at…
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…
Dijet cross sections in neutral current deep inelastic ep scattering have been measured in the range $10 < \Q2 < 10^4$ GeV$^2$ with the ZEUS detector at HERA using an integrated luminosity of 38.4 pb$^{-1}$. The cross sections, measured in…
After fifteen years of running and a further five years of analysis, the final inclusive deep inelastic scattering cross sections from H1 and ZEUS have been published. Measurements of neutral current and charged current processes in ep…
Deep inelastic e^+ scattering data, taken with the H1 detector at HERA, are used to study the event shape variables thrust, jet broadening and jet mass in the current hemisphere of the Breit frame over a large range of momentum transfers Q…
Deep-inelastic positron-proton scattering events at low photon virtuality Q^2 with a forward jet, produced at small angles with respect to the proton beam, are measured with the H1 detector at HERA. A subsample of events with an additional…
We demonstrate that perturbative QCD allows one to calculate the absolute cross section of diffractive exclusive production of photons at large $Q^2$ at HERA, while the aligned jet model allows one to estimate the cross section for…
We investigate the color coherence pattern between initial and final state radiation in the presence of a QCD medium. We derive the medium-induced gluon spectrum of an "asymptotic" parton which suffers a hard scattering and subsequently…
The parton momentum density distributions in the proton are determined from a next-to-leading order QCD analysis of structure functions measured at HERA and by fixed target experiments. Also included are data on the difference of the up and…
Forward jet cross sections have been measured in neutral current deep inelastic scattering at low Bjorken-x with the ZEUS detector at HERA using an integrated luminosity of ${81.8 \rm pb}^{-1}$. Measurements are presented for inclusive…
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.
Measurements of $D^{*}(2010)$ meson production in diffractive deep inelastic scattering $(5<Q^{2}<100~{\rm GeV}^{2})$ are presented which are based on HERA data recorded at a centre-of-mass energy $\sqrt{s} = 319{\rm~GeV}$ with an…
The QCD expectations concerning the deep inelastic lepton - hadron scattering at low $x$ and their phenomenological implications for HERA are summarised. Theoretical predictions for the structure function $F_2(x,Q^2)$ based on the leading…
The inclusive e^+ p single and double differential cross sections for neutral and charged current processes are measured with the H1 detector at HERA. The data were taken in 1999 and 2000 at a centre-of-mass energy of \sqrt{s} = 319 GeV and…
Since a lot of theoretical predictions on the production of new particles (Higgs, SUSY) at the Tevatron are based on model estimations of the proton gluon density behavior at low $x$ and high values of a transfered momentum Q^2, the study…
The QCD factorization theorem for diffractive processes in DIS is used to derive formulae for the leading twist contribution to the nuclear shadowing of parton distributions in the low thickness limit. Based on the current analyzes of…
There is a close analogy between electroweak instanton-induced baryon plus lepton number (B+L) violating processes in Quantum Flavor Dynamics (QFD) and hard QCD instanton-induced chirality violating processes in deep-inelastic scattering.…