Measurement of the Light Antiquark Flavor Asymmetry in the Nucleon Sea
Abstract
A precise measurement of the ratio of Drell-Yan yields from an 800 GeV/c proton beam incident on hydrogen and deuterium targets is reported. Over 140 000 Drell-Yan muon pairs with dimuon mass Mμ+μ->=4.5 GeV/c2 were recorded. From these data, the ratio of antidown ( d¯) to antiup ( u¯) quark distributions in the proton sea is determined over a wide range in Bjorken x. A strong x dependence is observed in the ratio d¯/u¯, showing substantial enhancement of d¯ with respect to u¯ for x<0.2. This result is in fair agreement with recent parton distribution parametrizations of the sea. For x>0.2, the observed d¯/u¯ ratio is much nearer unity than given by the parametrizations.
- Publication:
-
Physical Review Letters
- Pub Date:
- April 1998
- DOI:
- 10.1103/PhysRevLett.80.3715
- arXiv:
- arXiv:hep-ex/9803011
- Bibcode:
- 1998PhRvL..80.3715H
- Keywords:
-
- High Energy Physics - Experiment
- E-Print:
- REVTeX, to be published in Phys. Rev. Lett