|The 18th International Symposium on Spin Physics|
October 6-11, 2008
University of Virginia
Charlottesville, VA USA
|Title||Transversity, Sivers Function and Collins Fragmentation Functions: Towards a New Global Analysis|
| Abstract of 200 words or less
A new, preliminary global analysis of the experimental data on azimuthal asymmetries in SIDIS from HERMES and COMPASS collaborations, and in $e^+e^- \to h_1 h_2 X$ processes from the BELLE collaboration, is performed. The new data allow for a more precise determination of the Collins fragmentation function and of the transversity distribution function for $u$ and $d$ quarks, in comparison with the results of our previous analysis. Sivers functions for $u$ and $d$ and $sea$ quarks are extracted from the experimental data
of COMPASS and HERMES. Estimates for the single spin asymmetry in D-Y processes due to Sivers mechanism are presented.