Erlangen 2001 – scientific programme
Parts | Days | Selection | Search | Downloads | Help
HK: Physik der Hadronen und Kerne
HK 15: Theorie II
HK 15.1: Talk
Tuesday, March 20, 2001, 14:15–14:30, B
The Spin Structure of the Nucleon at Low Energies — •T.R. Hemmert — Physik-Department T39, TU München
Traditionally the spin structure of the nucleon has been discussed in terms of the 2 spin structure functions g1(x,Q2), g2(x,Q2), which are accessible in experiments using polarized leptons scattering off polarized targets. While the thrust of the experimental effort so far has been in the regime of deep inelastic scattering, recently the so-called resonance region Q2≤ 1GeV2 has attracted a lot of interest [1]. These efforts are supplemented by new experiments with polarized real photons at MAMI and ELSA to test the Gerasimov-Drell-Hearn (GDH) sum rule [2]. In this contribution I want to discuss how the so called “spin polarizabilities”, which can be probed in low energy polarized Real Compton Scattering (RCS) off a nucleon, and the so called “generalized spin polarizabilities”, which enter in low momentum Virtual Compton Scattering (VCS) off the nucleon, are connected with the spin structure functions in the resonance region. I will also give an overview of the existing calculations for spin-dependent nucleon structure effests in RCS [3], VCS [4] and discuss the status of the generalized GDH sum rule from the viewpoint of chiral effective field theories [5].
[1] see e.g. JLab Proposals 91-23, 93-09, 94-10, 97-110
[2] J. Ahrens et al., Phys. Rev. Lett. 84 (2000) 5950
[3] G.C. Gellas, T.R. Hemmert and U.-G. Meißner, Phys. Rev. Lett. 85 (2000) 14
[4] T.R. Hemmert et al., Phys. Rev. D62 (2000) 014013
[5] e.g. X. Ji, C.-W. Kao and J. Osborne, Phys. Lett. B472 (2000) 1