Flavor asymmetry of the light quark sea from semi-inclusive deep-inelastic scattering

K. Ackerstaff*, A. Airapetian, N. Akopov, I. Akushevich, M. Amarian, E.C. Ashenauer, H. Avakian, R. Avakian, A. Avetissian, B. Bains, C. Baumgarten, M. Beckmann, S. Belostotski, J.E. Belz, T. Benisch, S. Bernreuther, N. Bianchi, J. Blouw, H. Bottcher, A. BorissovJ. Brack, S. Brauksiepe, B. Braun, B. Bray, S. Brons, W. Bruckner, A. Brull, E.E.W. Bruins, K.J. Bulten, R.V. Cadman, G.P. Capitani, P. Carter, P. Chumney, E. Cisbani, G.R. Court, P.F. Dalpiaz, E. De Sanctis, D. De Schepper, E. Devitsin, P.K.A.D. Huberts, P. Di Nezza, M. Duren, A. Dvoredsky, G. Elbakian, A. Fantoni, A. Fechtchenko, M. Ferstl, K. Fiedler, B.W. Filippone, H. Fischer, J.F.J. van den Brand

*Corresponding author for this work

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Abstract

The flavor asymmetry of the light quark sea of the nucleon is determined in the kinematic range 0.02 < x < 0.3 and 1 < Q(2) < 10 GeV2 for the first time from semi-inclusive deep-inelastic scattering. The quantity [(d) over bar(x) - (u) over bar(x)]/[u(x) - d(x)] is derived from a relationship between the yields of positive and negative pions from unpolarized hydrogen and deuterium targets. The flavor asymmetry (d) over bar - (u) over bar is found to be nonzero and x dependent, showing an excess of (d) over bar over (u) over bar quarks in the proton.
Original languageEnglish
Pages (from-to)5519-5523
Number of pages5
JournalPhysical Review Letters
Volume81
Issue number25
DOIs
Publication statusPublished - 21 Dec 1998
Externally publishedYes

Keywords

  • DRELL-YAN PROCESS
  • PARTON DISTRIBUTIONS
  • BREAKING
  • NUCLEON
  • PROTON

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