Semi-inclusive and exclusive measurements with EIC: The advantages of lower energies

Abstract

Exploring the nucleon's sea quark and gluon structure is a prime objective of a future electron-ion collider (EIC). Many of the key questions require accurate differential semi-inclusive (spin/flavor decomposition, orbital motion) and exclusive (spatial distributions of quarks/gluons) DIS measurements in the region 0.01 < x < 0.3 and Q^2 ~ few 10 GeV^2. Such measurements could ideally be performed with a high-luminosity collider of moderate CM energy, s ~ 10^3 GeV^2, and relatively symmetric configuration, e.g. E_e/E_p = 5/30-60 GeV. Specific examples are presented, showing the advantages of this setup (angular/energy distribution of final-state particles, large-x coverage) compared to typical high-energy colliders.

5 pages, 3 figures. Proceedings of DIS 2009, 26-30 April 2009, Madrid