Recent positivity constraints for spin observables and parton distributions

Abstract

Spin observables allow a deeper understanding of the nature of the underlying dynamics and positivity reduces substantially their allowed domains. We will present some new positivity constraints for spin observables and their implications for parton distributions. We will also make some comparisons with recent data.

10 pages, 3 figures, Invited talk presented at the 14th Workshop on Elastic and Diffractive Scattering (EDS Blois Workshop), December 15-21, 2011, Qui Nhon, Vietnam (to be published in the Proceedings)