Related papers: Novel features in exclusive vector--meson producti…
In a previous publication, we have presented a model for the photoproduction of $\mathrm{J/}\psi$ vector mesons off protons, where the proton structure in the impact-parameter plane is described by an energy-dependent hot-spot profile. Here…
We investigate the efficiency of power generation by thermo-chemical engines. For strong coupling between the particle and heat flows and in the presence of a left-right symmetry in the system, we demonstrate that the efficiency at maximum…
A fully covariant approach to a density dependent hadron field theory is presented. The relation between in--medium NN interactions and field--theoretical meson--nucleon vertices is discussed. The medium dependence of nuclear interactions…
Recent results of particle production in the energy regime of the CERN-SPS are reviewed. In order to collect information on the properties of the QCD phase diagram systematic studies of the system size and the energy dependence of particle…
Theory and phenomenology of the eta_c photo- and electroproduction is developed from the point of view of probing the odderon singularity in QCD which corresponds to the three gluon exchange mechanism. This mechanism leads to the…
Two model-independent results on the momentum-dependence of $\rho$-$\omega$ mixing are described. First, an explicit choice of interpolating fields for the vector mesons is displayed for which both the mixing in the propagator and the…
Exclusive photoproduction of $\rho^0(770)$ mesons is studied using the H1 detector at the $ep$ collider HERA. A sample of about 900000 events is used to measure single- and double-differential cross sections for the reaction $\gamma p \to…
We study the production of spin-one mesons in high-energy heavy-ion collisions with peripheral kinematics in the framework of QED. The cross sections of the production of a single vector meson and of two different ones are presented. The…
Recent results from HERA are presented on a range of topics: charged multiplicities, production of non-strange mesons and strange particles, charm fragmentation, baryons decaying to strange particles, antideuteron production, Bose-Einstein…
Exclusive vector meson photoproduction associated with a leading baryon ($B = n, \Delta^+, \Delta^0$) in $pp$ and $pA$ collisions at RHIC and LHC energies is investigated using the color dipole formalism and taking into account nonlinear…
We discuss the coherent photo- and leptoproduction of vector mesons from deuterium at intermediate (virtual) photon energies, 3 GeV < nu < 30 GeV. These processes provide several options to explore the space-time evolution of small size…
Measurements of the cross section for exclusive virtual-photoproduction of rho^0 mesons from hydrogen are reported. The data were collected by the HERMES experiment using 27.5 GeV positrons incident on a hydrogen gas target in the HERA…
The processes of exclusive photo- and electroproduction of vector mesons $\rho^0$(770), $\phi$(1020) and $J/\psi$(3096) at collision energies $30 GeV<W<300 GeV$ and transferred momenta squared $0<-t<2 GeV^2$ are considered in the framework…
The exclusive production of pairs of vector mesons with J^{PC} = 1^{--} in e^+ e^- collisions can proceed through e^+ e^- annihilation into two virtual photons. At energies much greater than the meson masses, the cross section is dominated…
Exclusive $\rho^0$-meson electroproduction is studied by the HERMES experiment, using the 27.6 GeV longitudinally polarized electron/positron beam of HERA and a transversely polarized hydrogen target, in the kinematic region 1.0…
A first measurement is presented of exclusive photoproduction of $\rho^0$ mesons associated with leading neutrons at HERA. The data were taken with the H1 detector in the years 2006 and 2007 at a centre-of-mass energy of 319 GeV and…
It is reported on an analysis of vector meson electroproduction at small Bjorken-x within the handbag approach. Using a model for the generalized parton distribution and calculating the partonic subprocess, electroproduction off gluons,…
We calculate the momentum dependence of the $\rho$-meson selfenergy based on the dispersion relation for the $\rho N$ scattering amplitude $f(\omega$) at low nuclear density. The imaginary part of $f(\omega)$ is determined from the optical…
In this talk various spin effects in hard exclusive electroproduction of mesons are briefly reviewed and the data discussed in the light of recent theoretical calculations within the frame work of the handbag approach. For electroproduction…
HERA data on soft hadron production are discussed. The measured inclusive and exclusive hadron cross sections show a simple scaling behaviour.