1999/08/13 by A. Deshpande, Deshpande, A.
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Experiment (hep-ex) #hep-ex
paper · pdf · doi:10.48550/arxiv.hep-ex/9908051
Plenary Talk writeup: 19 Pages, 7 Figures; To appear in the Proceedings of ``The Workshop on Polarized Protons at High Energies - Accelerator Challenges and Physics Opportunities'', DESY, Hamburg, May 17-20, 1999
arxiv created 1999/08/13 · arxiv updated 2009/11/30
Several important and unique measurements, within the standard model and of possible physics beyond it, could be made with \em polarized HERA in which both the proton and the electron beams are polarized. With a ∼820 GeV proton beam and a ∼27.6 GeV electron beam, the polarized HERA will enable e-p collisions with √(s) ∼ 300 GeV and access spin variables in the kinematic range, 10-5 ≤ x\rm Bj ≤ 0.6 and 0 ≤ Q2 ≤ 105, using the H1 and ZEUS detectors at DESY. This will be an increase of two orders of magnitude in both x and Q2 range compared to the presently explored range from fixed target experiments at CERN, SLAC and DESY. No other approved or planned spin experiment or accelerator facility will access the low x and high Q2 regions possible with HERA. Measurements performed with the polarized HERA collider will include the polarized structure function g1(x,Q2) at very low x, the polarized gluon distribution ΔG(x,Q2) from pQCD analysis of g1, and from the production of di-jet events and high-pT hadrons in photon gluon fusion process and in photoproduction, the weak structure functions, the valence quark distribution functions from semi-inclusive asymmetries, parton distributions inside polarized photon, and information on helicity structure of possible new physics beyond the standard model. With such a rich and broad physics program possible for HERA,not polarizing the proton beam would be a great opportunity lost.