Abstract
A precise measurement of the ratio of Drell-Yan yields from an proton beam incident on hydrogen and deuterium targets is reported. Over 140 000 Drell-Yan muon pairs with dimuon mass were recorded. From these data, the ratio of antidown ( ) to antiup ( ) quark distributions in the proton sea is determined over a wide range in Bjorken . A strong dependence is observed in the ratio , showing substantial enhancement of with respect to for . This result is in fair agreement with recent parton distribution parametrizations of the sea. For , the observed ratio is much nearer unity than given by the parametrizations.
- Received 9 December 1997
DOI:https://doi.org/10.1103/PhysRevLett.80.3715
©1998 American Physical Society