Eur. Phys. J. C 18, 531-538
DOI: 10.1007/s100520100547

g₁ at low x and low Q² with Polarized ep colliders

S.D. Bass¹ and A. De Roeck<sup>2

1</sup>  Physik Department, Technische Universität München, 85747 Garching, Germany
²  CERN, 1211 Geneva 23, Switzerland

steven.bass@cern.ch
albert.de.roeck@cern.ch

(Received: 28 August 2000 / Revised version: 9 November 2000 / Published online: 21 December 2000 -© Springer-Verlag 2000)

Abstract
Measurements of g₁ at low x and low Q² are expected to provide a sensitive probe of the transition from Regge to perturbative QCD dynamics, offering a new testing ground for models of small x physics. We discuss the potential of polarized ep colliders (Polarized HERA and eRHIC) to investigate this physics -varying Q² between 0.01 and 1 GeV² -and to constrain the high-energy part of the Drell-Hearn-Gerasimov sum-rule for polarized photoproduction.

© Società Italiana di Fisica, Springer-Verlag 2001