Related papers: GPDs and spin effects in light mesons production
The forward electroproduction of two light vector mesons is the first example of a collision process between strongly interacting colorless particles for which the amplitude can be written completely within perturbative QCD in the Regge…
The cross section for bottom quark production at fixed-target energies is calculated for a wide range of beam momenta. A detailed analysis is given for the HERA-B experiment. We consider both the order $\alpha_s^3$ cross section and the…
It is shown that the origin of the striking left-right asymmetries observed in single-spin inclusive hadron production processes in high energy hadron-hadron collisions can be traced by performing suitable experiments. Several new…
H1 has measured a number of different known particles and compared their production to QCD models and to other reactions such as N-N collisions. ZEUS has also measured the production of K0SK0S pairs with a view to searching for glueballs.…
The elastic electroproduction of rho mesons is studied at HERA with the H1 detector for a photon virtuality in the range 1 < Q^2 < 60 GeV^2 and for a hadronic centre of mass energy in the range 30 < W < 140 GeV. The shape of the pipi mass…
First inclusive measurements of isolated prompt photons in photoproduction at HERA have been made with the ZEUS detector. Cross sections are given as a function of the pseudorapidity and the transverse energy of the photon, for E_T^gamma >…
A study of central meson production as a function of the difference in transverse momentum (dPT) of the exchanged particles shows that undisputed qqbar mesons are suppressed at small dPT whereas the glueball candidates are enhanced. In…
It has been realized for quite a long time that single-spin experiments, in which one of the colliding objects is transversely polarized, can be helpful in studying the properties of strong interaction in general and in testing Quantum…
Preliminary results obtained by the COMPASS experiment for longitudinal-spin-dependent azimuthal asymmetries in single-hadron muoproduction off protons are presented for the first time. The analysis was carried out on the full data sample…
We discuss possible measurements and origins of single spin asymmetries in DIS and of some unusual spin properties of vector mesons produced in lepton- nucleon, photon-nucleon and photon-photon interactions. Such effects have already been…
Hard exclusive production in deep inelastic lepton scattering provides access to the unknown Generalized Parton Distributions (GPDs) of the nucleon. At HERMES, different observables for hard exclusive pi^+ production have been measured with…
Inclusive production of $\mathrm{D^{*\pm}}$ mesons in two-photon collisions was measured by the L3 experiment at LEP. The data were collected at a centre-of-mass energy $\sqrt{s} = 189$ GeV with an integrated luminosity of $176.4…
Positivity constraints have proved to be important for spin observables of exclusive reactions involving polarized initial and final particles. Attention is focused in this note on the photoproduction of pseudoscalar mesons from spin 1/2…
We have measured the cross section and single spin asymmetries from forward $W^{\pm}\rightarrow\mu^{\pm}\nu$ production in longitudinally polarized $p$$+$$p$ collisions at $\sqrt{s}=510$ GeV using the PHENIX detector at the Relativistic…
The last decade has witnessed great experimental progress that has led to measurements of cross sections--polarized as well as unpolarized--of of high accuracy in several $NN \to NNx$ reaction channels. These data, naturally, pose…
We estimate the differential and total cross sections for both the photoproduction of vector D*-meson and its yield in deep inelastic scattering at the HERA collider in the framework of model motivated by perturbative calculations in QCD.…
We study the associated Higgs production with Z boson at future linear colliders in the framework of the minimal noncommutative standard model. Using the Seiberg-Witten map, we calculate the production cross-section considering all orders…
The handbag mechanism for wide-angle exclusive scattering reactions is discussed and compared to other theoretical approaches. The role of power laws in observables is critically examined. Applications of the handbag mechanism to Compton…
A consistent description of exclusive photoproduction of mesons at high momentum transfer t relies on a few effective degrees of freedom which can be checked against Lattice calculation or more effective models of QCD.
The possibilities to measure spin effects at a high-energy Electron-Ion Collider (EIC) are reviewed from a theory point of view. Various types of spin distributions and promising observables are discussed.