Related papers: Exclusive Pion-production and the Relation to Tran…
We report on a measurement of hard exclusive $\pi^0$ muoproduction on the proton by COMPASS using 160 GeV/$c$ polarised $\mu^+$ and $\mu^-$ beams of the CERN SPS impinging on a liquid hydrogen target. From the average of the measured…
Recent results on nucleon resonance studies in $\pi^{+}\pi^{-}p$ electro- production off protons with the CLAS detector are presented. The analysis of CLAS data allowed us to determine all essential contributing mechanisms, providing a…
We study the polarization of hyperon in different processes in singly polarized $pp$ collisions, in particular its relation to the polarized parton distributions. We show that by measuring hyperon polarization in particularly chosen…
A large set of cross sections for semi-inclusive electroproduction of charged pions ($\pi^\pm$) from both proton and deuteron targets was measured. The data are in the deep-inelastic scattering region with invariant mass squared $W^2$ > 4…
We discuss the electroproduction of light vector mesons from transversely polarized photons. Here QCD factorization cannot be applied as shown explicitly in a leading order calculation of corresponding Feynman diagrams. It is emphasized…
A single-spin asymmetry was measured in the azimuthal distribution of pi+pi- pairs produced in semi-inclusive deep-inelastic scattering on a transversely polarized hydrogen target. For the first time, evidence is found for a correlation…
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…
Semi-inclusive processes are very promising to investigate $XYZ$ hadrons at the next generation of electron-hadron facilities, because they generally boast higher cross sections. We extend our formalism of exclusive photoproduction to…
Large momentum transfer reactions such as pion production represent the frontier of Chiral Perturbation Theory and must be understood before more complex reactions can be considered. Pion production is also interesting in its own right, one…
We argue that the electroproduction of exotic particles is a useful tool for study of their partonic structure. In the case of hybrid mesons, the magnitude of their cross sections shows that they are accessible for measurements in existing…
We discuss the production of polarized hadrons in polarized lepton nucleon interactions and show that the helicity density matrix of the hadron, when measurable, can give information on the spin structure of the nucleon and the spin…
The exclusive electroproduction of pi+ mesons was studied with the Hermes spectrometer at the DESY laboratory by scattering 27.6 GeV positron and electron beams off an internal hydrogen gas target. The virtual-photon cross sections were…
Photoproduction of neutral and charged pions off nucleons and deuterium has been precisely calculated in baryon chiral perturbation theory. I review the predictions with the accurate data that have become available over the last few years.…
We discuss the relevance of studying single transverse-spin asymmetry in hard-exclusive meson electroproduction in the backward region. Such an asymmetry could help us discriminate between contributions from a soft baryon exchange in the…
We review our results on a new class of $2 \to 3$ exclusive processes, as a probe of both chiral-even and chiral-odd quark GPDs. We consider the exclusive photoproduction of a photon-meson pair, in the kinematics where the pair has a large…
We present deeply virtual $\pi^0$ electroproduction cross-section measurements at $x_B$=0.36 and three different $Q^2$--values ranging from 1.5 to 2 GeV$^2$, obtained from experiment E07-007 that ran in the Hall A at Jefferson Lab. The…
Pion electro- and photoproduction off the nucleon close to threshold is studied in covariant baryon chiral perturbation theory at O($p^3$) in the extended-on-mass-shell scheme, with the explicit inclusion of the $\Delta(1232)$ resonance.…
Pion photoproduction off the nucleon close to threshold is studied in covariant baryon chiral perturbation theory at O($p^3$) in the extended-on-mass-shell scheme, with the explicit inclusion of the $\Delta(1232)$ resonance using the…
We consider the central exclusive production of the $p\bar{p}$ in the continuum and via resonances in proton-proton collisions at high energies. We discuss the diffractive mechanism calculated within the tensor-pomeron approach including…
The cross section for exclusive production of $\pi^+ \pi^-$ and $\pi^0 \pi^0$ meson pairs in ultrarelativistic heavy ion collisions is calculated for LHC energy $\sqrt{s_{NN}} =$ 3.5 TeV taking into account photon-photon mechanism. We…