相关论文: Deep Inelastic Scattering Data and the Problem of …
Charge asymmetry in electron (positron) scattering arises from the interference of the Born amplitude and the box-type amplitude corresponding to two virtual photons exchange. It can be extracted from electron proton and positron proton…
The small-$x$ evolution of protons is determined from numerical solutions of the JIMWLK equations, starting from an initial condition at moderate $x$ for a finite size proton. The resulting dipole amplitude is used to calculate the total…
We begin the process of unitarizing the Pomeron at large 't Hooft coupling. We do so first in the conformal regime, which applies to good accuracy to a number of real and toy problems in QCD. We rewrite the conformal Pomeron in the…
The first measurement of diffractive scattering of quasi-real photons with large momentum transfer is made using the H1 detector at HERA. Single differential cross sections are measured as a function of W, the incident photon-proton centre…
A new framework, called x-scape, for the combined study of both hard and soft transverse momentum sectors in high energy proton-proton ($p$-$p$) and proton-nucleus ($p$-$A$) collisions is set up. A dynamical initial state is set up using…
Processes of hevy quark photoproduction at HERA energies and beyond are investigated using the semihard ($k_{\bot}$ factorization) approach. The virtuality and longitudinal polarization of gluons in the photon - gluon subprocess as well as…
A Pomeron model applicable to both "`soft" and "hard" processes is suggested and tested against the high-energy data from virtual photon-induced reactions. The Pomeron is universal, containing two terms, a "soft" and a "hard" one, whose…
We calculate polarization phenomena for virtual Compton scattering on protons, at relatively large momentum transfer 1 GeV$^2$ $\le -q^2\le$ 5 GeV$^2$ on the basis of a model for $\gamma^*+ p\to \gamma+p$ with two main contributions:…
Through a determination of the $S$-matrix element for the scattering of a localized colour dipole on a proton, we show that saturation effects can already be sizable at HERA. The saturation scale is found to be around 1-1.5 $GeV^2$ for the…
We use the Kovchegov-Levin equation to resum contributions of large invariant mass diffractive final states to diffractive structure functions in the dipole picture of deep inelastic scattering. For protons we use a (modified)…
We construct diffractive parton distributions in the model of DIS diffraction in which the diffractive state is formed by the $q\bar{q}$ and $q\bar{q}g$ components. The interaction of such systems with the proton is described by the dipole…
We examine the process of Deep Inelastic Scattering (DIS) in the small-x limit, where Pomeron exchange dominates. Using the AdS/CFT correspondence, we study Pomeron exchange in the dual string theory in AdS space, which allows us to study…
The physics scope of polarized nucleon-nucleon collisions originating from an internal polarized target in the HERA proton beam is summarized. Based on 240 pb^{-1} integrated luminosity at 40 GeV c.m. energy, statistical sensitivities are…
Measurements of multiplicity fluctuations of identified hadrons produced in inelastic p+p interactions at 31, 40, 80, and 158~\GeVc beam momentum are presented. Three different measures of multiplicity fluctuations are used: the scaled…
Photon propagation in a gas of N atoms is studied using an effective Hamiltonian describing photon mediated atomic dipolar interactions. The density P(\Gamma) of photon escape rates is determined from the spectrum of the N x N random matrix…
The measurement of the polarized gluon distribution function Delta G(x) from photon-gluon fusion processes in electron-proton deep inelastic scattering producing two jets has been investigated. The study is based on the MEPJET and PEPSI…
The amplitude for $\gamma p \to \phi p$ is calculated in a pQCD $k_{T}$ - factorization approach. The total cross section for this process is compared with HERA data. Total cross section, as a function of photon-proton energy and photon…
We present a detailed analysis of the polarized and the unpolarized deep inelastic scattering structure functions of the proton, g_1^p and F_2^p respectively, in the context of a holographic dual description based on type IIB superstring…
The structure of real and virtual photons has been studied in electron-proton scattering processes producing di-jet events at HERA by the H1 and ZEUS collaborations. Data have been compared to next-to-leading order QCD calculations and to…
The theoretical framework for a next-to-leading order QCD analysis of the spin-dependent parton densities Delta f^{gamma}(x,Q^2) of the longitudinally polarized photon and of its structure function g_1^{gamma}(x,Q^2) is reviewed in some…