ELFE : an Electron Laboratory for Europe

This paper presents a brief overview of the physics with the 15-30~GeV continuous beam electron facility proposed by the European community of nuclear physicists to study the quark and gluon structure of hadrons.Comment: need qcdparis.sty, psfig and 8 eps figures : exclusive_hard_1.eps exclusive_hard_2.eps exclusive_hard_3.eps hard_bw.eps gpm_slac.eps inclusif1.eps inclusif2.eps machine.ep

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.

gamma* gamma -> pi pi at large Q^2

The QCD analysis of the process gamma* gamma -> pi pi at large Q^2 and small center-of-mass energy allows one to access a new hadronic observable describing the exclusive transition from a q qbar or g g state to a pair of mesons. A fruitful study may be envisaged at existing machines.Comment: 7 pages, to appear in the Proceedings of PHOTON 2000, Ambleside, England, August 200

Baryon to meson transition distribution amplitudes and their spectral representation

We consider the problem of construction of a spectral representation for nucleon to meson transition distribution amplitudes (TDAs), non-diagonal matrix elements of nonlocal three quark light-cone operators between a nucleon and a meson states. We introduce the notion of quadruple distributions and generalize Radyshkin's factorized Ansatz for this issue. Modelling of baryon to meson TDAs in the complete domain of their definition opens the way to quantitative estimates of cross-sections for various hard exclusive reactions.Comment: Talk presented at International Workshop on Diffraction in High-Energy Physics DIFFRACTION 2010, September 10 - 15, 2010 Otranto (Lecce), Italy. 4 page