Related papers: Odderon and photon exchange in pseudoscalar meson …
We provide a statistically significant observation of the elusive Odderon exchange, based on novel and model-independent analysis of the scaling properties of the differential cross sections of elastic $pp$ and $p\bar p$ scattering in the…
A Dyson-Schwinger-based model of pomeron exchange is employed to calculate diffractive rho-, phi- and J/psi-meson electroproduction cross sections. It is shown that the magnitude of the current-quark mass m_f of the quark and antiquark…
A new form of two-photon exchange(TPE) effect is studied to explain the discrepancy between unpolarized and polarized experimental data in elastic $ep$ scattering. The mechanism is based on a simple idea that apart from the usual TPE…
Motivated by the renewed interest in studying the pion production on nuclei with protons at few GeV incident energies, we investigate the pion production in proton-proton collisions over an energy range of 300 $MeV$ to 2 $GeV$. Starting…
The differential cross section, $d\sigma/dt$ for $\omega$ meson exclusive photoproduction on the proton above the resonance region ($2.6<W<2.9$ GeV) was measured up to a momentum transfer $-t = 5$ GeV$^2$ using the CLAS detector at…
The inclusive production of charged hadrons in the collisions of quasi-real photons e+e- -> e+e- +X has been measured using the OPAL detector at LEP. The data were taken at e+e- centre-of-mass energies from 183 to 209 GeV. The differential…
A brief review on the Dipole Pomeron model is given. The model not only describes data on hadron-hadron interactions, but also allows to describe data on the proton structure function with a $Q^2$ independent intercept. Moreover the chosen…
Inclusive jet cross sections for events with a large rapidity gap with respect to the proton direction from the reaction $ep \rightarrow jet \; + \; X$ with quasi-real photons have been measured with the ZEUS detector. The cross sections…
The total hadronic photon-photon cross-section measured by L3 and OPAL and the apparent discrepancy between the results are discussed. OPAL measurements of jet and charged hadron production in photon-photon scattering and preliminary H1…
Experimental results obtained with the HERA collider and recent progress in their theoretical interpretation are reviewed. After a short introduction to HERA physics, deep inelastic scattering and photoproduction are discussed as (virtual)…
We extend the general formalism of two-photon exchange to elastic lepton-nucleon scattering by accounting for all lepton mass terms. We then perform a numerical estimate of the muon-proton scattering at low momentum transfer in view of the…
The reaction $\gamma p \rightarrow \omega p$ $(\omega \rightarrow \pi^+\pi^-\pi^0$ and $\pi^0\rightarrow\gamma\gamma)$ has been studied in $ep$ interactions using the ZEUS detector at photon-proton centre-of-mass energies between $70$ and…
The semi-inclusive reaction e+ p -> e+ X p was studied with the ZEUS detector at HERA using an integrated luminosity of 12.8 pb-1. The final-state proton, which was detected with the ZEUS leading proton spectrometer, carried a large…
There seem to be recently an evidence for $C =$ -1 exchanges in $p p$ and $p \bar p$ elastic scattering at high energies. The analysis there is difficult as the two processes were not measured at the same (large) energies. Here we discuss…
We review recent theoretical and experimental progress on the role of two-photon exchange (TPE) in electron-proton scattering at low to moderate momentum transfers. We make a detailed comparison and analysis of the results of competing…
We calculate the O(\alpha_s) corrections to the production of a hard and isolated photon accompanied by one or two jets in deep inelastic lepton nucleon scattering at HERA. Numerical results are presented and the potential of this process…
A Pomeron-exchange model of exclusive electroproduction of $\rho$-mesons is examined using a dressed-quark propagator. It is shown that by representing the photon-$\rho$-meson-Pomeron coupling by a nonperturbative, confined-quark loop, one…
The effect of axial meson exchange on extraction of proton electromagnetic form factors in $ep$ scattering is calculated. Taking as an example $f_1(1285)$ meson exchange, it is quantitatively shown how it affects Rosenbluth and polarization…
Central pseudoscalar production in $pp$ scattering is suppressed at small values of $Q_\perp$, where $Q$ is defined as the difference between the momenta transferred from the two protons. Such a behaviour is expected if the production…
We discuss diffractive photon-production of vector mesons in holographic QCD. At large $\sqrt{s}$, the QCD scattering amplitudes are reduced to the scattering of pair of dipoles exchanging a closed string or a pomeron. We use the…