Evidence for a single-spin azimuthal asymmetry in semi-inclusive pion electroproduction

HERMES Collaboration

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

Single-spin asymmetries for semi-inclusive pion production in deep-inelastic scattering have been measured for the first time. A significant target-spin asymmetry of the distribution in the azimuthal angle phi of the pion relative to the lepton scattering plane was formed for pi(+) electroproduction on a longitudinally polarized hydrogen target. The corresponding analyzing power in the sin phi moment of the cross section is 0.022 +/- 0.005 +/- 0.003. This result can be interpreted as the effect of terms in the cross section involving chiral-odd spin distribution functions in combination with a chiral-odd fragmentation function that is sensitive to the transverse polarization of the fragmenting quark.
Original languageEnglish
Pages (from-to)4047-4051
Number of pages5
JournalPhysical Review Letters
Volume84
Issue number18
DOIs
Publication statusPublished - 1 May 2000
Externally publishedYes

Keywords

  • FRAGMENTATION FUNCTIONS
  • ANALYZING POWER
  • DISTRIBUTIONS
  • LEPTOPRODUCTION
  • NUCLEONS
  • BEAM

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