Measurement of the light antiquark flavor asymmetry in the nucleon sea

Fermilab E866/NuSea Collaboration

Research output: Contribution to journalArticlepeer-review


A precise measurement of the ratio of Drell-Yan yields from an800GeV/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.

Original languageEnglish (US)
Pages (from-to)3715-3718
Number of pages4
JournalPhysical review letters
Issue number17
StatePublished - 1998

ASJC Scopus subject areas

  • Physics and Astronomy(all)


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