Workshop Description

Workshop Program

Workshop:

"Electromagnetic studies of nuclear systems" 

Conveners: Kees de Jager and Bernd Krusche

Description

Probing nuclear systems through the exchange of real or virtual photons has produced impressive results in a broad-ranging program. The present availability of continuous intense beams of electrons and photons with high polarization is being utilized to study a large number of aspects in nuclear systems. Proton knock-out from a range of nuclei is being studied to extract information on relativistic effects, final-state interactions and meson-exchange corrections. Double nucleon knock-out is yielding surprising results on short-range correlations. Few-body systems are probed to study the elastic form factors of the ground state up to very high values of the momentum transfer. The Gerasimov-Drell-Hearn Sum Rule is being tested for the neutron using a polarized deuteron target. The electromagnetic couplings of excited states of the neutron are being studied with polarized and unpolarized beams on polarized and unpolarized deuterium targets. Other aspects of the spin structure of the neutron are being investigated with a polarized 3He target. Modifications of the proton and some of its excited states, as well as of mesons like the rho, omega and sigma meson, by the nuclear medium are probed sensitively. Kaon electro-production from nuclei has the advantage of a large angular momentum transfer, strong spin-flip contributions and a significantly improved energy resolution.  A high energy resolution (to separate the individual states in the hypernuclear system) and a high beam intensity (to compensate for the small cross section) are essential requirements for such studies.  Color transparency, the reduced interaction of small-sized hadrons at high velocity, has recently been observed for the first time at medium energies in electroproduction of rho mesons. The process in which the color field of a hadron develops in the nuclear medium, requires a broad program of deep-inelastic scattering over a range of nuclei, as well as the energy and momentum transfer. Studies of photo-induced reactions on various nuclei can provide important input on astrophysical processes. Meson production and baryon resonance excitation has been investigated on a number of nuclei, providing sensitive information on a variety of nuclear properties, among which the radius of the neutron distribution.

Program