Can the Collins mechanism explain the large transverse single spin asymmetries observed in p(transv. polarized) p --> pion X?
arXiv:hep-ph/0412236 · doi:10.1142/9789812701909_0060
Abstract
We present a calculation of inclusive polarised and unpolarised cross sections within pQCD and the factorisation scheme, taking into account the parton intrinsic motion, k_T, in distribution and fragmentation functions, as well as in the elementary dynamics. We show, in contradiction with earlier claims, that the Collins mechanism is suppressed and unable to explain the large asymmetries found in p(transv. polarized) p --> pion X at moderate to large Feynman x_F. The Sivers effect is not suppressed.
LaTeX 2e, 5 pages, 1 ps figure, uses ws-procs9x6. Talk delivered by U. D'Alesio at the ``16th International Spin Physics Symposium'', SPIN2004, October 10-16, 2004, Trieste, Italy