Physics – High Energy Physics – High Energy Physics - Phenomenology
Scientific paper
2009-04-20
AIP Conf.Proc.1149:527-532,2009
Physics
High Energy Physics
High Energy Physics - Phenomenology
5 pages, 4 figures, Spin 2008 contribution, to be published in Proceedings
Scientific paper
10.1063/1.3215704
Exclusive pi0 electroproduction from nucleons at large photon virtuality can be described in terms of Generalized Parton Distributions, particularly the chiral odd subset. Chiral odd GPDs are related to transversity and can be accessed experimentally for various special choices of observables. This is accomplished by choosing C-parity odd and chiral odd combinations of t-channel exchange quantum numbers. These GPDs are calculated in a spectator model, and are constrained by boundary functions. Alternatively, the production amplitudes correspond to C-odd Regge exchanges with final state interactions. The helicity structure of the virtual photoproduction amplitudes provides relations between the partonic description via GPDs and the hadronic, Regge description of C-odd processes, all via quark helicity flip. GPDs, in general, are analytic functions of energy variables. Their integrals over unobservable parton momenta thereby satisfy Dispersion Relations (DR). Using DR's could allow the real part of the amplitudes, the integrated GPDs, to be extracted from the more easily measured imaginary parts. However, at non-zero momentum transfer DRs require integration over unphysical regions of the variables. We show that the relevant unphysical region of the non-forward DRs is considerable. This will vitiate the efforts to avoid the actual measurement of the real parts more directly.
Goldstein Gary R.
Liuti Simonetta
No associations
LandOfFree
Exclusive Meson Electroproduction: GPDs, Regge and Dispersion Relations does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Exclusive Meson Electroproduction: GPDs, Regge and Dispersion Relations, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Exclusive Meson Electroproduction: GPDs, Regge and Dispersion Relations will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-174402