D-bar over u-bar asymmetry in a proton and Drell-Yan processes.

Abstract

We investigate the extent to which Drell-Yan processes may be used to shed light on the [ital [bar d]] over [ital [bar u]] asymmetry in a proton, as implied by the recent finding of the New Muon Collaboration. To this end, we consider the Drell-Yan production experiment either with an 800 GeV proton beam or with a 200 GeV [pi][sup [plus minus]] or [ital K][sup [plus minus]] beam, readily feasible at Fermilab (as a fixed target experiment). Numerical results indicate that the measurement of the [ital p]/[ital N] (proton-to-nucleon, i.e., normalized proton-to-deuteron) Drell-Yan production cross-section ratio is a suitable choice for unraveling the [ital [bar d]] over [ital [bar u]] asymmetry in a proton. The results also suggest that an experiment with a 200 GeV [pi][sup [minus]] or [ital K][sup [minus]] beam is not suitable for this particular purpose although the calculated ratio differs significantly from unity.