Physics Letters B (Jul 2018)

Semi-inclusive π0 target and beam-target asymmetries from 6 GeV electron scattering with CLAS

  • S. Jawalkar,
  • S. Koirala,
  • H. Avakian,
  • P. Bosted,
  • K.A. Griffioen,
  • C. Keith,
  • S.E. Kuhn,
  • K.P. Adhikari,
  • S. Adhikari,
  • D. Adikaram,
  • Z. Akbar,
  • M.J. Amaryan,
  • S. Anefalos Pereira,
  • J. Ball,
  • N.A. Baltzell,
  • M. Battaglieri,
  • V. Batourine,
  • I. Bedlinskiy,
  • A.S. Biselli,
  • S. Boiarinov,
  • W.J. Briscoe,
  • J. Brock,
  • W.K. Brooks,
  • S. Bültmann,
  • V.D. Burkert,
  • Frank Thanh Cao,
  • C. Carlin,
  • D.S. Carman,
  • A. Celentano,
  • G. Charles,
  • T. Chetry,
  • G. Ciullo,
  • L. Clark,
  • L. Colaneri,
  • P.L. Cole,
  • M. Contalbrigo,
  • O. Cortes,
  • V. Crede,
  • A. D'Angelo,
  • N. Dashyan,
  • R. De Vita,
  • E. De Sanctis,
  • M. Defurne,
  • A. Deur,
  • C. Djalali,
  • G. Ddoge,
  • R. Dupre,
  • H. Egiyan,
  • A. El Alaoui,
  • L. El Fassi,
  • L. Elouadrhiri,
  • P. Eugenio,
  • G. Fedotov,
  • S. Fegan,
  • R. Fersch,
  • A. Filippi,
  • J.A. Fleming,
  • T.A. Forest,
  • A. Fradi,
  • M. Garçon,
  • Y. Ghandilyan,
  • G.P. Gilfoyle,
  • K.L. Giovanetti,
  • F.X. Girod,
  • C. Gleason,
  • W. Gohn,
  • E. Golovatch,
  • R.W. Gothe,
  • M. Guidal,
  • N. Guler,
  • L. Guo,
  • H. Hakobyan,
  • C. Hanretty,
  • N. Harrison,
  • M. Hattawy,
  • D. Heddle,
  • K. Hicks,
  • G. Hollis,
  • M. Holtrop,
  • S.M. Hughes,
  • Y. Ilieva,
  • D.G. Ireland,
  • B.S. Ishkhanov,
  • E.L. Isupov,
  • D. Jenkins,
  • H. Jiang,
  • K. Joo,
  • S. Joosten,
  • D. Keller,
  • G. Khachatryan,
  • M. Khachatryan,
  • M. Khandaker,
  • A. Kim,
  • W. Kim,
  • A. Klein,
  • F.J. Klein,
  • V. Kubarovsky,
  • S.V. Kuleshov,
  • L. Lanza,
  • P. Lenisa,
  • K. Livingston,
  • H.Y. Lu,
  • I.J.D. MacGregor,
  • N. Markov,
  • M. Mayer,
  • M.E. McCracken,
  • B. McKinnon,
  • C.A. Meyer,
  • T. Mineeva,
  • M. Mirazita,
  • V. Mokeev,
  • R.A. Montgomery,
  • A. Movsisyan,
  • C. Munoz Camacho,
  • P. Nadel-Turonski,
  • L.A. Net,
  • S. Niccolai,
  • G. Niculescu,
  • I. Niculescu,
  • M. Osipenko,
  • A.I. Ostrovidov,
  • R. Paremuzyan,
  • K. Park,
  • E. Pasyuk,
  • E. Phelps,
  • W. Phelps,
  • J. Pierce,
  • S. Pisano,
  • O. Pogorelko,
  • J.W. Price,
  • Y. Prok,
  • D. Protopopescu,
  • B.A. Raue,
  • M. Ripani,
  • D. Riser,
  • A. Rizzo,
  • G. Rosner,
  • P. Rossi,
  • F. Sabatié,
  • C. Salgado,
  • R.A. Schumacher,
  • E. Seder,
  • Y.G. Sharabian,
  • A. Simonyan,
  • Iu. Skorodumina,
  • G.D. Smith,
  • D.I. Sober,
  • D. Sokhan,
  • N. Sparveris,
  • I. Stankovic,
  • S. Strauch,
  • M. Taiuti,
  • M. Ungaro,
  • H. Voskanyan,
  • E. Voutier,
  • N.K. Walford,
  • D.P. Watts,
  • X. Wei,
  • L.B. Weinstein,
  • M.H. Wood,
  • N. Zachariou,
  • J. Zhang,
  • Z.W. Zhao

Journal volume & issue
Vol. 782
pp. 662 – 667

Abstract

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We present precision measurements of the target and beam-target spin asymmetries from neutral pion electroproduction in deep-inelastic scattering (DIS) using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. We scattered 6-GeV, longitudinally polarized electrons off longitudinally polarized protons in a cryogenic 14NH3 target, and extracted double and single target spin asymmetries for ep→e′π0X in multidimensional bins in four-momentum transfer (1.0<Q2<3.2 GeV2), Bjorken-x (0.12<x<0.48), hadron energy fraction (0.4<z<0.7), transverse pion momentum (0<PT<1.0 GeV), and azimuthal angle ϕh between the lepton scattering and hadron production planes. We extracted asymmetries as a function of both x and PT, which provide access to transverse-momentum distributions of longitudinally polarized quarks. The double spin asymmetries depend weakly on PT. The sin⁡2ϕh moments are zero within uncertainties, which is consistent with the expected suppression of the Collins fragmentation function. The observed sin⁡ϕh moments suggest that quark gluon correlations are significant at large x. Keywords: Semi-inclusive deep-inelastic scattering, Single spin asymmetries, Double spin asymmetries, Transverse momentum distributions, Collins fragmentation