Related papers: Pionic transparency in semi-exclusive electroprodu…
In these proceedings we present preliminary $\pi^{+}\pi^{-}$ electroproduction cross sections off protons in the kinematical area of 1.4 GeV $< W <$ 1.8 GeV and 0.4 GeV$^{2}$ $< Q^{2} < 1.1$ GeV$^{2}$. Our results extend the kinematical…
The cross section for exclusive $\pi^+\pi^-$ and $\pi^0\pi^0$ meson pairs production in peripheral ultrarelativistic heavy-ion collisions is calculated at the energy available at the CERN Large Hadron Collider, i.e., $\sqrt{s_{NN}}=3.5$…
Hard exclusive electroproduction of $\pi^+\pi^-$ pairs off hydrogen and deuterium targets has been studied by the HERMES experiment at DESY. Legendre moments $<P_1>$ and $<P_3>$ of the angular distributions of $\pi^+$ mesons in the…
The exclusive electroproduction process $ep \rightarrow e'p'\pi^{0}$ was measured in the range of photon virtualities $Q^{2} = 0.4 - 1.0$~GeV$^{2}$ and the invariant mass range of the $p\pi^{0}$ system of $W = 1.1 - 1.8$~GeV. These…
The (\pi^{-}\Delta^{++}) production on the nucleon by real and virtual photons is discussed as initial step in a simple model approach for the two pion photo- and electroproduction on the nucleon, with emphasis on nucleon resonance…
We revisit the notion of nuclear parton-to-pion fragmentation functions at next-to-leading order accuracy as an effective description of hadroproduction in nuclear environments such as in semi-inclusive lepton-nucleus deep-inelastic…
We study the hard exclusive production of two pions in the virtual photon fragmentation region with various invariant masses including the resonance region. The amplitude is expressed in terms of two-pion light cone distribution amplitudes…
The $\gamma\gamma\to\pi\pi$ reactions are discussed. To describe those processes, we include dipion continuum, resonances, high-energy pion-pion rescatterings, $\rho$ meson exchange and pQCD Brodsky-Lepage mechanisms. The cross section for…
I review hard photon initiated processes on nuclei. The space-time development of the DIS reaction as viewed in the target rest frame qualitatively describes the nuclear shadowing of quark and gluon distributions, although it may be…
A search for exclusive or semi-exclusive photon pair production, pp to p(*) + photon pair + p(*) (where p(*) stands for a diffractively-dissociated proton), and the observation of exclusive and semi-exclusive electron pair production, pp to…
In this paper we propose the analysis of the heavy quark photoproduction associated with a leading neutron in hadronic collisions at the LHC as an alternative to probe the pion gluon distribution in a kinematical range not covered by…
We report on the first measurement of cross sections for exclusive deeply virtual pion electroproduction off the proton, $e p \to e^\prime n \pi^+$, above the resonance region at backward pion center-of-mass angles. The…
Colour transparency is a cute and indispensable property of QCD as the gauge theory of strong interaction. CT tests of QCD consist of production of the perturbative small-sized hadronic state and measuring the strngth of its…
An effective field theory with hadrons and photons is constructed, where the hadronic parameters are determined by fitting elastic $\pi$N scattering data. The predicted pion-induced $\eta$-production on the nucleon agrees well with the…
We outline major ideas involved in discussion of color coherence phenomena (CCP) at intermediate energies. We point out that the recent advances in calculating cross sections of hard exclusive processes off light nuclei allow to use the…
Particle and photon production is analyzed in the presence of transverse flow using two approximations to describe the properties of the hadronic medium, one containing only $\pi, \rho, \omega$, and $\eta$ mesons (simplified equation of…
We consider a novel class of hard branching hadronic processes a+b->c+d+e, where hadrons c and d have large and nearly opposite transverse momenta and large invariant energy which is a finite fraction of the total invariant energy. We use…
In this work we study the diffractive photoproduction of $J/\Psi$ in proton-proton, proton - nucleus and nucleus - nucleus collisions at LHC energies using the color dipole formalism and different models for the forward dipole - target…
At the energies of present and future electron accelerators designed to study the structure of hadrons, there is a regime where hard pion electroproduction proceeds by a perturbatively calculable process in QCD. The process is not the…
We investigate electroproduction of pion pairs on the nucleon in the framework of QCD factorization for hard exclusive processes. We extend previous analyses by taking the hard-scattering coefficients at next-to-leading order in $\alpha_s$.…