arXiv:hep-ph/9906418·v1·High Energy Physics — Phenomenology
Predictions for single spin asymmetries in lepton + p(transv. polarized) -> pion + X and gamma^* + p(transv. polarized) -> pion + X
M. Anselmino (1) · M. Boglione (2) · J. Hansson (3) · F. Murgia (4) ((1) University and INFN, Torino, Italy, (2) Vrije Universiteit, Amsterdam, The Netherlands, (3) Lulea University of Technology, Lulea, Sweden, (4) INFN and University, Cagliari, Italy)
Abstract
Predictions for the single transverse spin asymmetry A_N in semi-inclusive DIS processes are given; non negligible values of A_N may arise from spin effects in the fragmentation of a polarized quark into a final hadron with a transverse momentum k_T with respect to the jet axis, the so-called Collins effect. The elementary single spin asymmetry of the fragmenting quark has been fixed in a previous paper, by fitting data on p(transv. polarized) + P -> pion + X, and the predictions given here are uniquely based on the assumption that the Collins effect is the only cause of the observed single spin asymmetries in p(transv. polarized) + p -> pion + X. Eventual spin and k_T dependences in quark distribution functions, the so-called Sivers effect, are also discussed.
Comments: 22+1 pages, LaTeX, 12 eps figures, uses epsfig.sty