COMPASS-Ⅱ

摘要

On December the 1st, 2010, the proposal of the COMPASS-Ⅱ experiment has been approved by the CERN Research Board. After almost ten years of important results achieved by the COMPASS Collaboration in both nucleon spin physics, with the use of muon beam, and hadron spectroscopy, using hadron beams, this second phase offers now a unique chance to address in the very near future newly opened QCD-related challenges, at very moderate upgrade cost, thanks to the versatility of the COMPASS apparatus. This implies mainly study of chiral perturbation theory (ChPT), by measuring the pion polarizability through the Primakoff reaction; generalized partem distributions (GPDs), by measuring exclusive deeply virtual Compton scattering (DVCS) and hard exclusive meson production (DVMP); transverse momentum-dependent partom distributions (TMDs) in single-polarized pion-induced Drell-Yan muon production and in SIDIS on a liquid hydrogen target (in parallel to DVCS). An overview of the COMPASS-Ⅱ proposal is presented here, with a main focus on the new upcoming investigation of the nucleon structure via the Drell-Yan and DVCS processes.