[en] At the LEALE laboratory a monochromatic photon beam with energy in the range 80/300 MeV is available. Photons are produced by positron annihilation on a liquid hydrogen target. The characteristics of the beam are calculated for various conditions (positron energy, photon collimator, target thickness), taking into account the effects contributing to the beam spreading (energy loss and multiple scattering of protons in the annihilation target, energy distribution and angular divergence of the positron beam). (author)

[en] Nearly complete angular distributions of the two-body deuteron photodisintegration differential cross section have been measured using the CEBAF Large Acceptance Spectrometer detector and the tagged photon beam at the Thomas Jefferson National Accelerator Facility. The data cover photon energies between 0.5 and 3.0 GeV and center-of-mass proton scattering angles 10^o-160^o. The data show a persistent forward-backward angle asymmetry over the explored energy range, and are well described by the nonperturbative quark gluon string model

[en] We consider the cosphi dependence of the longitudinal double-spin asymmetry for charged pion electroproduction in semi-inclusive deep inelastic scattering, emphasizing intrinsic transverse momentum effects. This azimuthal asymmetry allows to measure the cosphi moments of the unpolarized and double-spin cross-section, simultaneously. The size of the asymmetry, in the approximation where all twist-3 interaction-dependent distribution and fragmentation functions are set to zero, is estimated for HERMES kinematics; both the spin-independent and the double-spin cosphi moments are predicted to be sizable and negative

[en] An outline is presented of the ongoing research in photonuclear reactions at the Frascati photon facilities: LADON and LEALE

No abstract available

[en] The azimuthal single target-spin asymmetries for π⁺ production in semi-inclusive deep inelastic scattering of leptons off longitudinally polarized protons are evaluated using two main approaches available in the literature. It is shown that the approximation where the twist-2 transverse quark spin distribution in the longitudinally polarized nucleon is small enough to be neglected leads to a consistent description of all existing asymmetries observed by the HERMES experiment

[en] We consider the sinphi single target-spin asymmetry in deep-inelastic π⁺ inclusive electroproduction off a longitudinally polarized target. We show that at larger transverse momentum of the outgoing hadron the evaluated asymmetry decreases if one takes into account the first order α_S perturbative contribution to the cross section, integrated over the azimuthal angle. This leads to good agreement with recent HERMES data

[en] The experimental data for the photodisintegration of deuteron are reviewed, with emphasis on areas where previous problems appear to be solved and where there is current activity. Recent data, measured in an extended photon energy range using monochromatic photon beams, agree among each other within the total quoted errors. They are now of sufficient quality to better constrain the theory. 42 refs, 6 figs, 2 tabs

[en] We propose to measure the differential cross section for the deuteron photodisintegration at t=0±0.125 (GeV/cc)² and over the energy range from 0.9 to 1.5 GeV, in order to check the prediction of the Regge phenomenology. The experiment can use the CEBAF Large Acceptance Spectrometer (CLAS) and run concurrently with PR-89--045, ''Studies of kaon photoproduction on deuterium.'' The time request for data taking is for 200 hours. In this time we expect the data accumulated in angular bins of about 10 degree and energy bins of 100 MeV will have 0.8% and 1.8% statistical errors (neglecting background), repectively at the lower and higher ends of the energy range

No abstract available