Color Transparency at ELFE

We review the presentations given in the Color Transparency parallel session held during the second ELFE workshop.Comment: Report on the Color Transparency parallel session held during the second ELFE workshop, Saint Malo, France, September 1996, to be published in the Proceedings, N. d'Hose et al ed.(Nuclear Physics A). e-mail: [email protected] and [email protected]

Neutrino-production of a charmed meson and the transverse spin structure of the nucleon

We calculate the amplitude for exclusive neutrino production of a charmed meson on an unpolarized target, in the colinear QCD approach where generalized parton distributions (GPDs) factorize from perturbatively calculable coefficient functions. We demonstrate that the transversity chiral odd GPDs contribute to the transverse cross section if the hard amplitude is calculated up to order mc/Q. We show how to access these GPDs through the azimuthal dependence of the nu N -> mu D N differential cross section.Comment: 5 pages, 1 figure. Version 2 adds a few clarifications and references. As published in Physical Review Letters 115, 092001 (2015

The nucleon's transversity and the photon's distribution amplitude probed in lepton pair photoproduction

We describe a new way to access the chiral odd transversity parton distribution in the proton through the photoproduction of lepton pairs on transversely polarized target. The basic ingredient is the interference of the Bethe Heitler or Drell-Yan amplitudes with the amplitude of a process, where the photon couples to quarks through its twist-2 chiral-odd distribution amplitude. This approach permits to scan experimentally the shape of the transversity distribution in a nucleon as well as the photon distribution amplitude.Comment: 4 pages, proceedings of the ICHEP conference, Paris july 201

Deeply Virtual Compton Scattering on the Deuteron

We study deeply virtual Compton scattering (DVCS) on a deuteron target. We model the Generalized Quark Distributions in the deuteron by using the impulse approximation for the lowest Fock-space state. Numerical predictions are given for the unpolarized cross sections for the kinematical regimes relevant for JLab and HERMES at HERA. Differential cross sections show the same pattern as for the proton case and at low values of t they are of comparable size.Comment: 6 pages, 4 eps figures. Contribution to the European Workshop on the QCD Structure of the Nucleon (QCD-N'02), Ferrara, Italy, 3-6 Apr 200

Nucleon Form Factors '99

We review recent progress in the experimental knowledge of and theoretical speculations about nucleon form factors, with special emphasis on the large Q2 region.Comment: 4 pages, latex, no figures. Report on the Form Factor session held during the Nucleon99 workshop, Frascati, Italy, June 1999, to be published in Nucl. Phys.

Double diffractive rho-production in gamma^* gamma^* collisions

We present a first estimate of the cross-section for the exclusive process gamma^*_L (Q_1^2) gamma^*_L(Q_2^2) -> rho^0_L rho^0_L, which will be studied in the future high energy e^+ e^- linear collider. As a first step, we calculate the Born order approximation of the amplitude for longitudinally polarized virtual photons and mesons, in the kinematical region s >> -t, Q_1^2, Q_2^2. This process is completely calculable in the hard region Q_1^2, Q_2^2 >> Lambda^2_{QCD}. We perform most of the steps in an analytical way. The resulting cross-section turns out to be large enough for this process to be measurable with foreseen luminosity and energy, for Q_1^2 and Q_2^2 in the range of a few GeV^2.Comment: 25 pages, 5 figures. Published version in EPJC. Minor changes and several references added with respect to v