High density QCD at THERA

AbstractThese notes are a summary of our predictions for the new THERA project, relatedto deep inelastic scattering in the region of ultra low x ( x → 10 −7 ). We collect herepredictions that satisfy two criteria (i) they do not depend on specific features of themodel that we have to use to estimate a possible effect; and (ii) they do not contradictthe HERA data. 1 Introduction: Our hopes and main goals at THERA 1.1 Three domains of QCD at low x Deep inelastic scattering is a unique experiment which allows us to take ‘snapshots’ of theconstituents inside a hadron at different moments of time with different resolutions. These‘snapshots’ provide the possibility of finding the degrees of freedom (DOF) that are responsi-ble for the interaction in QCD and generalize the theoretical approach from the well defineddomain of perturbative QCD to the unknown non-perturbative ( confinement ) region, wherethe appropriate theoretical methods are still to be determined. DIS allows one to see theconstituents of size ≈ 1/Q, where Q is the photon virtuality, at the time t ≈ 1/mx, wherex is the Bjorken variable related to the energy (W) of the process (x = Q