NA51 Collaboration: People and labs
About Physics : The purpose of the experiment is to investigate whether the light quark sea in the nucleon is SU(2) isospin symmetric or not, i.e. wether ubar is different from dbar. The experiment is based on the Drell-Yan process in proton-nucleon collisions which is intended to discriminate between the two interpretations of the NMC results. This experiment uses a 450 GeV/c primary proton beam from the CERN SPS at an average intensity of 10^9 protons per second. Muon pairs are detected with the NA10 spectrometer. The targets were mounted on a remote-controlled table which allowed to change periodically (every run) the target exposed to the beam.
The results of the experiment
The ratio 
of the light quark sea parton
distributions in the nucleon deduced from this measurement is
at 
This result is a clear indication of isospin symmetry violation in the light quark sea of the nucleon.
Publications, Communications,
Reports, Thesis
Last update March 15th, 1995, fom