Spin polarisabilities of the nucleon at NLO in the chiral expansion

Abstract

We present a calculation of the fourth-order (NLO) contribution to spin-dependent Compton scattering in heavy-baryon chiral perturbation theory, and we give results for the four spin polarisabilities. These results have been presented before, in hep-ph/0002133. Here we address the issue of whether one-particle reducible graphs in the heavy baryon theory contribute to the polarisabilities.

Comments: 6 pages, 2 figures, talk given at GDH2000, Mainz, June 14-17 2000