Single-spin azimuthal asymmetry in exclusive electroproduction of pi(+) mesons

HERMES Collaboration

Research output: Contribution to journalArticleAcademicpeer-review


A single-spin asymmetry in the distribution of exclusively produced pi(+) mesons azimuthally around the virtual photon direction relative to the lepton scattering plane has been measured for the first time in deep-inelastic scattering of positrons off longitudinally polarized protons. Integrated over the experimental acceptance, the sin moment of the polarization asymmetry of the cross section is measured to be -0.18 +/- 0.05(stat.) +/- 0.02(syst.). The asymmetry is also studied as a function of the relevant kinematic variables, and its magnitude is found to grow with decreasing x and increasing -t and vanish at t --> t(min) (where x is the Bjorken scaling variable and t is the squared four-momentum transferred to the nucleon). (C) 2002 Elsevier Science B.V. All rights reserved.
Original languageEnglish
Pages (from-to)85-92
Number of pages8
JournalPhysics Letters B
Issue number1-4
Publication statusPublished - 23 May 2002
Externally publishedYes



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