APS » PROLA » Phys. Rev. Lett. » Volume 80 » Issue 17

Phys. Rev. Lett. 80, 3715 - 3718 (1998)

Measurement of the Light Antiquark Flavor Asymmetry in the Nucleon Sea
Download: PDF (155 kB) or Buy this Article (Use Article Pack) Export: BibTeX or EndNote (RIS)

E. A. Hawker et al. (Fermilab E866/NuSea Collaboration)
Show All Authors/Affiliations

Received 9 December 1997; revised 13 February 1998

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 ( d̅ ) to antiup ( u̅ ) quark distributions in the proton sea is determined over a wide range in Bjorken x. A strong x dependence is observed in the ratio d̅ /u̅ , showing substantial enhancement of d̅ with respect to u̅ for x<0.2. This result is in fair agreement with recent parton distribution parametrizations of the sea. For x>0.2, the observed d̅ /u̅ ratio is much nearer unity than given by the parametrizations.


©1998 The American Physical Society

URL: http://link.aps.org/abstract/PRL/v80/p3715
DOI: 10.1103/PhysRevLett.80.3715
PACS: 13.85.Qk, 14.20.Dh, 24.85.+p, 25.40.Ve

* Present address: University of Illinois, Urbana, IL 61801.
† Also with University of Texas, Austin, TX 78712.
‡ On leave from Kurchatov Institute, Moscow 123182, Russia.

[ Abstract  |  Previous article  |  Next article  |  Issue 17 ]