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Leading-order determination of the gluon polarization from high-p T hadron electroproduction

  • The Hermes collaboration
  • A. Airapetian
  • N. Akopov
  • Z. Akopov
  • E. C. Aschenauer
  • W. Augustyniak
  • R. Avakian
  • A. Avetissian
  • E. Avetisyan
  • S. Belostotski
  • N. Bianchi
  • H. P. Blok
  • H. Böttcher
  • C. Bonomo
  • A. Borissov
  • V. Bryzgalov
  • M. Capiluppi
  • G. P. Capitani
  • E. Cisbani
  • M. Contalbrigo
  • P. F. Dalpiaz
  • W. Deconinck
  • R. De Leo
  • M. Demey
  • L. De Nardo
  • E. De Sanctis
  • M. Diefenthaler
  • P. Di Nezza
  • J. Dreschler
  • M. Düren
  • M. Ehrenfried
  • G. Elbakian
  • F. Ellinghaus
  • U. Elschenbroich
  • R. Fabbri
  • A. Fantoni
  • L. Felawka
  • S. Frullani
  • D. Gabbert
  • G. Gapienko
  • V. Gapienko
  • F. Garibaldi
  • G. Gavrilov
  • V. Gharibyan
  • F. Giordano
  • S. Gliske
  • H. Guler
  • C. Hadjidakis
  • M. Hartig
  • D. Hasch
  • T. Hasegawa
  • G. Hill
  • A. Hillenbrand
  • M. Hoek
  • Y. Holler
  • B. Hommez
  • I. Hristova
  • A. Ivanilov
  • H. E. Jackson
  • R. Kaiser
  • T. Keri
  • E. Kinney
  • A. Kisselev
  • M. Kopytin
  • V. Korotkov
  • P. Kravchenko
  • L. Lagamba
  • R. Lamb
  • L. Lapikás
  • I. Lehmann
  • P. Lenisa
  • P. Liebing
  • L. A. Linden-Levy
  • W. Lorenzon
  • X.-R. Lu
  • B. Maiheu
  • N. C. R. Makins
  • B. Marianski
  • H. Marukyan
  • V. Mexner
  • C. A. Miller
  • Y. Miyachi
  • V. Muccifora
  • M. Murray
  • A. Mussgiller
  • E. Nappi
  • Y. Naryshkin
  • A. Nass
  • M. Negodaev
  • W.-D. Nowak
  • L. L. Pappalardo
  • R. Perez-Benito
  • N. Pickert
  • M. Raithel
  • D. Reggiani
  • P. E. Reimer
  • A. Reischl
  • A. R. Reolon
  • C. Riedl
  • K. RithEmail author
  • S. E. Rock
  • G. Rosner
  • A. Rostomyan
  • J. Rubin
  • Y. Salomatin
  • A. Schäfer
  • G. Schnell
  • K. P. Schüler
  • B. Seitz
  • C. Shearer
  • T.-A. Shibata
  • V. Shutov
  • M. Stancari
  • M. Statera
  • J. J. M. Steijger
  • J. Stewart
  • F. Stinzing
  • S. Taroian
  • B. Tchuiko
  • A. Trzcinski
  • M. Tytgat
  • A. Vandenbroucke
  • P. B. van der Nat
  • G. van der Steenhoven
  • Y. Van Haarlem
  • C. Van Hulse
  • M. Varanda
  • D. Veretennikov
  • I. Vilardi
  • C. Vogel
  • S. Wang
  • S. Yaschenko
  • H. Ye
  • Z. Ye
  • W. Yu
  • D. Zeiler
  • B. Zihlmann
  • P. Zupranski
Open Access
Article

Abstract

Longitudinal double-spin asymmetries of charged hadrons with high transverse momentum p T have been measured in electroproduction using the Hermes detector at Hera. Processes involving gluons in the nucleon have been enhanced relative to others by selecting hadrons with p T typically above 1 GeV. In this kinematic domain the gluon polarization has been extracted in leading order making use of the model embedded in the Monte Carlo Generator Pythia 6.2. The gluon polarization obtained from single inclusive hadrons in the p T range 1 GeV < p T < 2.5 GeV using a deuterium target is \( \frac{{\Delta g}}{g}\left( {\left\langle x \right\rangle, \left\langle {{\mu^2}} \right\rangle } \right) = 0.049\pm 0.034\left( {stat} \right)\pm 0.010\left( {sys\text{-}exp} \right)_{ - 0.099}^{ + 0.126}\left( {sys\text{-}models} \right) \) at a scale \( \left\langle {{\mu^2}} \right\rangle = 1.35\;{\text{Ge}}{{\text{V}}^2} \) and \( \left\langle x \right\rangle = 0.22 \). For different final states and kinematic domains, consistent values of \( \frac{{\Delta g}}{g} \) have been found within statistical uncertainties using hydrogen and deuterium targets.

Keywords

Lepton-Nucleon Scattering 

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Open Access This article is distributed under the terms of the Creative Commons Attribution License which permits any use, distribution and reproduction in any medium, provided the original author(s) and source are credited.

Authors and Affiliations

  • The Hermes collaboration
  • A. Airapetian
    • 12
    • 15
  • N. Akopov
    • 25
  • Z. Akopov
    • 5
  • E. C. Aschenauer
    • 6
    • 26
  • W. Augustyniak
    • 24
  • R. Avakian
    • 25
  • A. Avetissian
    • 25
  • E. Avetisyan
    • 5
  • S. Belostotski
    • 17
  • N. Bianchi
    • 10
  • H. P. Blok
    • 16
    • 23
  • H. Böttcher
    • 6
  • C. Bonomo
    • 9
  • A. Borissov
    • 5
  • V. Bryzgalov
    • 18
  • M. Capiluppi
    • 9
  • G. P. Capitani
    • 10
  • E. Cisbani
    • 20
  • M. Contalbrigo
    • 9
  • P. F. Dalpiaz
    • 9
  • W. Deconinck
    • 5
    • 15
    • 27
  • R. De Leo
    • 2
  • M. Demey
    • 16
  • L. De Nardo
    • 15
    • 5
  • E. De Sanctis
    • 10
  • M. Diefenthaler
    • 14
    • 8
  • P. Di Nezza
    • 10
  • J. Dreschler
    • 16
  • M. Düren
    • 12
  • M. Ehrenfried
    • 12
  • G. Elbakian
    • 25
  • F. Ellinghaus
    • 4
    • 28
  • U. Elschenbroich
    • 11
  • R. Fabbri
    • 6
  • A. Fantoni
    • 10
  • L. Felawka
    • 21
  • S. Frullani
    • 20
  • D. Gabbert
    • 11
    • 6
  • G. Gapienko
    • 18
  • V. Gapienko
    • 18
  • F. Garibaldi
    • 20
  • G. Gavrilov
    • 5
    • 17
    • 21
  • V. Gharibyan
    • 25
  • F. Giordano
    • 5
    • 9
  • S. Gliske
    • 15
  • H. Guler
    • 6
  • C. Hadjidakis
    • 10
    • 29
  • M. Hartig
    • 5
    • 30
  • D. Hasch
    • 10
  • T. Hasegawa
    • 22
  • G. Hill
    • 13
  • A. Hillenbrand
    • 6
  • M. Hoek
    • 13
  • Y. Holler
    • 5
  • B. Hommez
    • 11
  • I. Hristova
    • 6
  • A. Ivanilov
    • 18
  • H. E. Jackson
    • 1
  • R. Kaiser
    • 13
  • T. Keri
    • 13
    • 12
  • E. Kinney
    • 4
  • A. Kisselev
    • 17
  • M. Kopytin
    • 6
  • V. Korotkov
    • 18
  • P. Kravchenko
    • 17
  • L. Lagamba
    • 2
  • R. Lamb
    • 14
  • L. Lapikás
    • 16
  • I. Lehmann
    • 13
  • P. Lenisa
    • 9
  • P. Liebing
    • 6
    • 31
  • L. A. Linden-Levy
    • 14
  • W. Lorenzon
    • 15
  • X.-R. Lu
    • 22
  • B. Maiheu
    • 11
  • N. C. R. Makins
    • 14
  • B. Marianski
    • 24
  • H. Marukyan
    • 25
  • V. Mexner
    • 16
  • C. A. Miller
    • 21
  • Y. Miyachi
    • 22
  • V. Muccifora
    • 10
  • M. Murray
    • 13
  • A. Mussgiller
    • 5
    • 8
  • E. Nappi
    • 2
  • Y. Naryshkin
    • 17
  • A. Nass
    • 8
  • M. Negodaev
    • 6
  • W.-D. Nowak
    • 6
  • L. L. Pappalardo
    • 9
  • R. Perez-Benito
    • 12
  • N. Pickert
    • 8
  • M. Raithel
    • 8
  • D. Reggiani
    • 8
  • P. E. Reimer
    • 1
  • A. Reischl
    • 16
  • A. R. Reolon
    • 10
  • C. Riedl
    • 6
  • K. Rith
    • 8
    Email author
  • S. E. Rock
    • 5
    • 32
  • G. Rosner
    • 13
  • A. Rostomyan
    • 5
  • J. Rubin
    • 1
    • 14
  • Y. Salomatin
    • 18
  • A. Schäfer
    • 19
  • G. Schnell
    • 6
    • 22
  • K. P. Schüler
    • 5
  • B. Seitz
    • 13
  • C. Shearer
    • 13
  • T.-A. Shibata
    • 22
  • V. Shutov
    • 7
  • M. Stancari
    • 9
  • M. Statera
    • 9
  • J. J. M. Steijger
    • 16
  • J. Stewart
    • 6
  • F. Stinzing
    • 8
  • S. Taroian
    • 25
  • B. Tchuiko
    • 18
  • A. Trzcinski
    • 24
  • M. Tytgat
    • 11
  • A. Vandenbroucke
    • 11
  • P. B. van der Nat
    • 16
  • G. van der Steenhoven
    • 16
  • Y. Van Haarlem
    • 11
    • 33
  • C. Van Hulse
    • 11
  • M. Varanda
    • 5
  • D. Veretennikov
    • 17
  • I. Vilardi
    • 2
  • C. Vogel
    • 8
  • S. Wang
    • 3
  • S. Yaschenko
    • 6
    • 8
  • H. Ye
    • 3
  • Z. Ye
    • 5
  • W. Yu
    • 12
  • D. Zeiler
    • 8
  • B. Zihlmann
    • 11
  • P. Zupranski
    • 24
  1. 1.Physics DivisionArgonne National LaboratoryArgonneU.S.A.
  2. 2.Istituto Nazionale di Fisica NucleareSezione di BariBariItaly
  3. 3.School of PhysicsPeking UniversityBeijingChina
  4. 4.Nuclear Physics LaboratoryUniversity of ColoradoBoulderU.S.A.
  5. 5.DESYHamburgGermany
  6. 6.DESYZeuthenGermany
  7. 7.Joint Institute for Nuclear ResearchDubnaRussia
  8. 8.Physikalisches InstitutUniversität Erlangen-NürnbergErlangenGermany
  9. 9.Istituto Nazionale di Fisica Nucleare, Sezione di Ferrara and Dipartimento di FisicaUniversità di FerraraFerraraItaly
  10. 10.Istituto Nazionale di Fisica NucleareLaboratori Nazionali di FrascatiFrascatiItaly
  11. 11.Department of Subatomic and Radiation PhysicsUniversity of GentGentBelgium
  12. 12.Physikalisches InstitutUniversität GießenGießenGermany
  13. 13.Department of Physics and AstronomyUniversity of GlasgowGlasgowU.K.
  14. 14.Department of PhysicsUniversity of IllinoisUrbanaU.S.A.
  15. 15.Randall Laboratory of PhysicsUniversity of MichiganAnn ArborU.S.A.
  16. 16.National Institute for Subatomic Physics (Nikhef)AmsterdamThe Netherlands
  17. 17.Petersburg Nuclear Physics InstituteGatchinaRussia
  18. 18.Institute for High Energy PhysicsProtvinoRussia
  19. 19.Institut für Theoretische PhysikUniversität RegensburgRegensburgGermany
  20. 20.Istituto Nazionale di Fisica Nucleare, Sezione Roma 1, Gruppo Sanità and Physics LaboratoryIstituto Superiore di SanitàRomaItaly
  21. 21.TRIUMFVancouverCanada
  22. 22.Department of PhysicsTokyo Institute of TechnologyTokyoJapan
  23. 23.Department of Physics & AstronomyVU UniversityAmsterdamThe Netherlands
  24. 24.Andrzej Soltan Institute for Nuclear StudiesWarsawPoland
  25. 25.Yerevan Physics InstituteYerevanArmenia
  26. 26.Brookhaven National LaboratoryUptonU.S.A.
  27. 27.Massachusetts Institute of TechnologyCambridgeU.S.A.
  28. 28.Institut für PhysikUniversität MainzMainzGermany
  29. 29.IPN (UMR 8608) CNRS/IN2P3 - Université Paris-SudOrsayFrance
  30. 30.Institut für KernphysikUniversität Frankfurt a.M.Frankfurt a.M.Germany
  31. 31.Institute of Environmental Physics and Remote SensingUniversity of BremenBremenGermany
  32. 32.SLAC National Accelerator LaboratoryMenlo ParkU.S.A.
  33. 33.Carnegie Mellon UniversityPittsburghU.S.A.

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