2008/05/14 by S. Arnold, Arnold, S., A. V. Efremov +9
Physics and Astronomy · #High-Energy Particle Collisions Research #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions #hep-ph
paper · pdf · doi:10.48550/arxiv.0805.2137
20 pages, 8 figures. Prepared for the CLAS 12 RICH Detector Workshop, January 28-29, 2008, Jefferson Lab, Newport News, VA, USA
arxiv created 2008/05/14 · arxiv updated 2009/12/01
Single spin asymmetries in semi-inclusive deep-inelastic scattering off transversely polarized targets give information on, among other fascinating effects, a pseudo time-reversal odd parton distribution function, the 'Sivers function'. In this proceeding we review the extractions of this function from HERMES and COMPASS data. In particular, the HERMES pion and kaon data suggest significant sea-quarks contributions at x ≃ 0.15 to the Sivers effect. We present a new fit that includes all relevant sea quark distributions and gives a statistically satisfactory overall description of the data, but does not describe ideally the K+ data from HERMES. We argue that measurements of the pion- and kaon Sivers effect at CLAS12, and COMPASS, will clarify the situation.