FERMILAB E866/NUSEA FINAL RESULTS FOR THE LIGHT ANTIQUARK ASYMMETRY IN THE NUCLEON AND PLANS FOR EXTENDING THESE MEASUREMENTS TO HIGHER BJORKEN X

摘要

Final results from the measurements of the ratio of Drell-Yan yields from an 800 GeV/c proton beam incident on liquid hydrogen and deuterium targets are shown. From these data, the ratio of anti-down (d) to anti-up (u) quark distributions in the proton sea is determined over a wide range in Bjorken-x. These measurements unexpectedly suggest considerable x dependence in this ratio at x >0.2. Fermilab P906 will be described, in which we propose to make precise measurements of this (x) dependence using proton induced Drell-Yan reactions at 120 GeV/c. This will allow the extension of the E866 measurements to significantly higher x. In P906 we also proposes to precisely measure the change in the u distributions in nuclear targets at x >0.2.