Related papers: The evolution of $\sigma^{\gamma P}$ with coherenc…
New results on the Deeply Virtual Compton Scattering process $\gamma^* p \to \gamma p$ (DVCS) from H1 experiment at the $e p$ collider HERA are presented, using data collected during the year 2004 and corresponding to an integrated…
The total cross section for the photoproduction process with a leading proton in the final state has been measured at gamma p centre-of-mass energies W of 91, 181 and 231 GeV. The measured cross sections apply to the kinematic range with…
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:…
We have predicted the difference in inclusive cross sections on pseudorapidity in ${\rm d}\sigma^{p\bar{p}}/{\rm d}\eta$ and ${\rm d}\sigma^{pp}/{\rm d}\eta$ interactions at $\sqrt{s}=900$~GeV. Their ratio $R=\left({\rm…
Quantum fluctuations in spacetime can, in some cases, lead to distortion in astronomical images of faraway objects. In particular, a stochastic model of quantum gravity predicts an accumulated fluctuation in the path length $\Delta L$ with…
We investigate the role of unitarization effects in virtual photon-proton (\gamma^*p) interactions at small x. The q\bar{q}-fluctuation of the initial photon is separated into a small distance and a large distance component and a model for…
The exclusive production of proton-antiproton pairs in the collisions of two quasi-real photons had been studied using data taken at sqrt(s)_ee=183 GeV and 189 GeV with the OPAL detector at LEP. Results are presented for Ppbar invariant…
Double parton scattering, occurring in high energy hadron-hadron collisions, e.g. at the LHC, is usually investigated through model dependent analyses of the so called effective cross section $\sigma_{eff}$. We present a dynamic approach to…
Measurements of the total cross section for real and virtual photons on protons at center-of-mass energies in the range from 20 GeV to 270 GeV with photon virtualities up to 5000 GeV^2 are presented. For real photons this cross section can…
Constraints on the quantum decoherence of entangled $\gamma$ quanta at the mega-electron-volt scale, such as those produced following positron annihilation, have remained elusive for many decades. We present the first statistically and…
We calculate differential distributions for the $p p \to p p \gamma$ reaction at the LHC energy $\sqrt{s} = 14$ TeV. We consider diffractive classical bremsstrahlung mechanisms including effects of non point-like nature of protons. In…
Using vector meson dominance we calculate the $\gamma\gamma$ total cross section from data on $pp$, $p\bar p$ and $\gamma p$ total cross sections. Our result agrees with recent high energy measurements performed by the L3 experiment at the…
We present first calculations of the fluctuating gluon distribution in a proton as a function of impact parameter and rapidity employing the functional Langevin form of the JIMWLK renormalization group equation. We demonstrate that when…
Via molecular dynamics simulations of a generic glass former in the supercooled and normal liquid states, it is shown that spatial correlations of strain fluctuations exhibit a crossover from the well-established power-law $\sim…
We study the kinematics and cross section of the scattering process $e p \rightarrow e \Sigma^+$. The cross section is expressed in terms of complex form factors characterizing the hadron vertices. We estimate the cross section for small…
We study, via computer simulations, the fluctuations in the net electric charge, in a two dimensional one component plasma (OCP) with uniform background charge density $-e \rho$, in a region $\Lambda$ inside a much larger overall neutral…
The theorem is proved, determining the forward scatterring amplitude of virtual longitudinal photon at zero energy on any hadronic target in the limit of small photon virtualities $Q^2$. The theorem is strict, based only on Lorenz and gauge…
The status of measurements and interpretation of the proton structure function F2 is summarized. The measurements are subjected to DGLAP fits, from which the gluon density is extracted and a comparison to measurements of F2c is performed.…
The photon-proton total cross section has been measured in the process e+ p -> e+ gamma p -> e+ X with the ZEUS detector at HERA. Events were collected with photon virtuality Q^2 < 0.02 GeV^2 and average gamma-p center-of-mass energy…
Vacuum polarisation in QED in a background gravitational field induces interactions which effectively violate the strong equivalence principle and affect the propagation of light. In the low frequency limit, Drummond and Hathrell have shown…