A Drift Chamber for a Muon Spectrometer and Measurement of Sea Quark Flavor Asymmetry in the Proton at E906/SeaQuest Drell-Yan Experiment

Abstract

Fermilab E-906/SeaQuest is a particle physics experiment which will use Drell-Yan process to measure the contributions of antiquarks to the structure of the proton or neutron and how this structure is modified when the proton or neutron is included within an atomic nucleus. It is part of a series of fixed target Drell-Yan experiments. 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 which then decays into a pair of oppositely-charged muons. The kinematics of these myons allow a direct relation to the antiquark structure of the proton. In addition the E-906/SeaQuest experiment can also examine the modifications to the antiquark structure of the proton from nuclear binding or access transverse momentum dependent parton distribution functions. The E906/SeaQuest experiment will use a 120 GeV proton beam extracted from the Fermilab Main Injector. This beam energy provides a tremendously increasing cross section compared to past Drell-Yan experiments. Taking the reduction of background events due to J/Ψ decays into account a gain in statistics by a factor of 50 compared to the latest Drell-Yan experiments is expected. The spectrometer is currently being assembled at Fermilab. It is expected to be commissioned in spring 2011 and collect data for two years. The group of Tokyo Institute of Technology is among Japanese collaborators in charge of the tracking stations in the E-906/SeaQuest experiment. In this report we will give an overview and a status report of the ongoing commissioning of the Drift Chambers (DC).