Related papers: Final States in Photon-Photon and Photon-Proton In…
To settle the question whether the growth with energy is universal for different hadronic total cross-sections, we present results from theoretical models for pion-proton, proton-proton and proton-antiproton total cross-sections. We show…
Inclusive photoproduction cross-sections of the neutral mesons eta, rho^0, f_0(980) and f_2(1270) have been measured by H1 and compared to the photoproduction of pi^+ in ep collisions at HERA. Also, inclusive KsKs production and evidence…
Data from the HERA collider experiments, H1 and ZEUS, have been fundamental to the rapid recent development of our understanding of the partonic composition of the proton and of QCD. This report focuses on inclusive measurements of neutral…
Using hadronic Lagrangians that include the interaction of pentaquark $\Theta^+$ baryon with $K$ and $N$, we evaluate the cross sections for its production from meson-proton, proton-proton, and photon-proton reactions near threshold. With…
Charge-odd correlation of the charged pair components produced at electron-proton scattering can measure three current correlation averaged by proton state. In general these type correlation can be described by 14 structure functions. We…
The associated production of a J/psi and a photon in photon-hadron collisions is considered, and shown to be a good probe of the presence of colour-octet mediated channels in quarkonia production, as predicted by the factorization approach…
This talk reviews the latest measurements of the proton, Pomeron and photon structure functions. These measurements, especially at low $x$ and/or low $Q^2$ lead to new insight into the picture of hadronic interactions.
Incoherent $\eta$-photoproduction on the deuteron is studied for photon energies from threshold up to 720 MeV. The elementary $\gamma N \to \eta N$ amplitude is constructed in the frame of a conventional isobar model. Effects of final state…
We present a study of high-$p_T$ photon and pion production in hadronic interactions, focusing on a comparison of the yields with expectations from next-to-leading order perturbative QCD (NLO pQCD). We examine the impact of phenomenological…
Multi-electron and multi-muon production at high transverse momentum is measured in $ep$ scattering at HERA. Previous published analyses are extended, combining new HERA II data taken in 2003-2004 with previous HERA I data sample. In…
Experiments that study the photoproduction of pseudoscalar mesons; pions, etas and kaons, have the potential to increase our knowledge of baryon and hyperon resonance properties. Recent experiments at JLab, Mainz, GRAAL, and Bonn are…
We present new data for the polarization observables of the final state proton in the $^{1}H(\vec{\gamma},\vec{p})\pi^{0}$ reaction. These data can be used to test predictions based on hadron helicity conservation (HHC) and perturbative QCD…
A phenomenological model which has had some success in explaining polarization phenomena and left-right asymmetry in inclusive proton-proton scattering is considered for reactions involving photons. In particular, the reactions (a) $ \gamma…
We show that the recent measurements of the total photoproduction cross section at HERA energies [1] are in agreement with our earlier prediction based on high-energy hadronic structure of the photon in the QCD minijet-type model [2]. We…
Recent measurements of QCD interactions involving large momentum transfers are reviewed. The status of measurements of the strong coupling constant is summarised. Recent developments in the measurement and interpretation of deep inelastic…
Two-photon processes in relativistic heavy-ion collisions have emerged as a critical probe of quantum electrodynamics in ultra-intense electromagnetic fields, with recent focus extending beyond dileptons to hadronic final states. At…
In view of possible photoproduction studies in ultraperipheral heavy-ion collisions at the LHC, we briefly review the present theoretical understanding of photons and hard photoproduction processes at HERA, discussing the production of…
At the electron-proton collider HERA the inclusive $D^{*\pm}$ meson photoproduction cross section has been measured with the H1 detector in two different, but partly overlapping, kinematical regions. For the first, where $<W_{\gamma p}>…
Neutrino cross section and oscillation measurements depend critically on modeling of hadronic final state interactions (FSI). Often, this is one of the largest components of uncertainty in a measurement. This is because of the difficulty in…
We present a unified view of the frequency dependence of the various scattering processes involved when a neutral hydrogen atom interacts with a monochromatic, linearly-polarized photon. A computational approach is employed of the atom…