2004/12/31 by A. Bianconi, Marco Radici, M. Radici · 2 citations
Physics and Astronomy · #Antiproton #Drell–Yan process #Electron #High-Energy Particle Collisions Research #Lepton #Monte Carlo method #Nuclear physics #Nucleon #Particle physics #Particle physics theoretical and experimental studies #Parton #Physics #Proton #Quantum Chromodynamics and Particle Interactions #Quark #Spin (aerodynamics) #hep-ph
paper · pdf · doi:10.1103/physrevd.71.074014
published as Phys.Rev. D71 (2005) 074014 · Deeply revised text with improved discussion of kinematics and results; added one table; 12 figures. Accepted for publication in Phys. Rev. D
arxiv created 2005/04/01 · openalex publication_date 2005/04/15 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
The complete knowledge of the nucleon spin structure at leading twist requires also addressing the transverse spin distribution of quarks, or transversity, which is yet unexplored because of its chiral-odd nature. Transversity can be best extracted from single-spin asymmetries in fully polarized Drell-Yan processes with antiprotons, where valence contributions are involved anyway. Alternatively, in single-polarized Drell-Yan the transversity happens convoluted with another chiral-odd function, which is likely to be responsible for the well known (and yet unexplained) violation of the Lam-Tung sum rule in the corresponding unpolarized cross section. We present Monte Carlo simulations for the unpolarized and single-polarized Drell-Yan pp^(\ensuremath\uparrow)\ensuremath→\ensuremathμ+\ensuremathμ^\ensuremath-X at different center-of-mass energies in both configurations where the antiproton beam hits a fixed proton target or it collides on another proton beam. The goal is to estimate the minimum number of events needed to extract the above chiral-odd distributions from future measurements at the high energy storage ring (HESR) at GSI. It is important to study the feasibility of such experiments at HESR in order to demonstrate that interesting spin physics can be explored already using unpolarized antiprotons.