The COMPASS experiment at CERN in Geneva studied the spin structure of the proton by deep inelastic muon -proton scattering. In particular, the spin contributions of the quarks and gluons are examined, as are the contributions by their orbital angular momenta.

  • COMPASS stands for Common Muon Proton Apparatus for Structure and Spectroscopy.
  • COMPASS began data collection in the summer of 2002.