..., the primary focus of this experiment was to measure the asymmetry of down and up antiquarks in the nucleon sea using Drell-Yan di-muons. The first Drell-Yan experiment was performed on E-866/NuSea at Fermilab with 800-GeV proton beam interactions with liquid hydrogen and deuterium targets. To extend these measurements to larger Bjorken-x, E-906/SeaQuest has been approved by Fermilab. It will use a 120 GeV proton beam extracted from the Fermilab Main Injector instead. In addition to extending the down to up antiquark measurements, the experiment will also examine the modifications to the antiquark structure of the proton from nuclear binding.
The
Drell–Yan process occurs in high energy hadron–hadron scattering. It takes
place when a
quark of one
hadron and an antiquark
of another hadron
annihilate, creating a virtual photon or Z boson
which then decays into a pair of oppositely-charged
leptons. This process was first suggested by
Sidney Drell and Tung-Mow Yan
in 1970
to describe the production of lepton-antilepton
pairs in high-energy hadron collisions. Experimentally, this process
was first observed by J.H. Christenson et al. in proton–uranium
collisions at the
Brookhaven National Laboratory,
Alternating Gradient Synchrotron.