Published April 2017 | Version v1
Journal article Metadata-only

Leading-order determination of the gluon polarisation from semi-inclusive deep inelastic scattering data

Creators

  • 1. Universitaet Erlangen-Nuernberg, Physikalisches Institut, Erlangen (Germany)
  • 2. INFN, Trieste (Italy)
  • 3. Joint Institute for Nuclear Research, Dubna, Moscow region (Russian Federation)
  • 4. University of Turin, Department of Physics, Turin (Italy)
  • 5. INFN, Turin (Italy)
  • 6. CEA IRFU/SPhN Saclay, Gif-sur-Yvette (France)
  • 7. National Centre for Nuclear Research, Warsaw (Poland)
  • 8. Technische Universitaet Muenchen, Physik Department, Garching (Germany)
  • 9. University of Aveiro, Department of Physics, Aveiro (Portugal)
  • 10. University of Warsaw, Faculty of Physics, Warsaw (Poland)
  • 11. Universitaet Bonn, Physikalisches Institut, Bonn (Germany)
  • 12. Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik, Bonn (Germany)
  • 13. CERN, Geneva 23 (Switzerland)
  • 14. Universitaet Mainz, Institut fuer Kernphysik, Mainz (Germany)
  • 15. Charles University in Prague, Faculty of Mathematics and Physics, Prague (Czech Republic)
  • 16. LIP, Lisbon (Portugal)
  • 17. University of Trieste, Department of Physics, Trieste (Italy)
  • 18. Universitaet Freiburg, Physikalisches Institut, Freiburg (Germany)
  • 19. Academia Sinica, Institute of Physics, Taipei (China)
  • 20. University of Illinois at Urbana-Champaign, Department of Physics, Urbana, IL (United States)
  • 21. Abdus Salam ICTP, Trieste (Italy)
  • 22. Matrivani Institute of Experimental Research and Education, Calcutta (India)
  • 23. State Scientific Center Institute for High Energy Physics of National Research Center 'Kurchatov Institute', Protvino (Russian Federation)
  • 24. Yamagata University, Yamagata (Japan)
  • 25. Warsaw University of Technology, Institute of Radioelectronics, Warsaw (Poland)

Description

Using a novel analysis technique, the gluon polarisation in the nucleon is re-evaluated using the longitudinal double-spin asymmetry measured in the cross section of semi-inclusive single-hadron muoproduction with photon virtuality Q2 > 1 (GeV/c)2. The data were obtained by the COMPASS experiment at CERN using a 160 GeV/c polarised muon beam impinging on a polarised 6LiD target. By analysing the full range in hadron transverse momentum pT, the different pT-dependences of the underlying processes are separated using a neural-network approach. In the absence of pQCD calculations at next-to-leading order in the selected kinematic domain, the gluon polarisation Δg/g is evaluated at leading order in pQCD at a hard scale of μ2 = left angle Q2 right angle = 3 (GeV/c)2. It is determined in three intervals of the nucleon momentum fraction carried by gluons, xg, covering the range 0.04 < xg < 0.28 and does not exhibit a significant dependence on xg. The average over the three intervals, left angle Δg/g right angle = 0.113 ± 0.038(stat.) ± 0.036(syst.) at left angle xg right angle ∼ 0.10, suggests that the gluon polarisation is positive in the measured xg range. (orig.)

Availability note (English)

Available from: http://dx.doi.org/10.1140/epjc/s10052-017-4716-x

Additional details

Identifiers

DOI
10.1140/epjc/s10052-017-4716-x;

Publishing Information

Journal Title
European Physical Journal. C, Particles and Fields (Online)
Journal Volume
77
Journal Issue
4
Journal Page Range
p. 1-12
ISSN
1434-6052

INIS

Country of Publication
Germany
Country of Input or Organization
Germany
INIS RN
48053361
Subject category
S72: PHYSICS OF ELEMENTARY PARTICLES AND FIELDS;
Resource subtype / Literary indicator
Numerical Data
Descriptors DEI
COMPUTERIZED SIMULATION; DATA ANALYSIS; DEEP INELASTIC SCATTERING; DEUTERIUM TARGET; GEV RANGE 100-1000; GLUON MODEL; LITHIUM 6 TARGET; MONTE CARLO METHOD; MUON REACTIONS; MUON-NUCLEON INTERACTIONS; NEURAL NETWORKS; NUCLEONS; PARTICLE STRUCTURE; POLARIZATION-ASYMMETRY RATIO; POLARIZED TARGETS; RELATIVISTIC RANGE; SEMI-INCLUSIVE INTERACTIONS; SPIN ORIENTATION; THEORETICAL DATA; TRANSVERSE MOMENTUM
Descriptors DEC
BARYONS; CALCULATION METHODS; CHARGED-PARTICLE REACTIONS; DATA; DATA PROCESSING; DIMENSIONLESS NUMBERS; ELEMENTARY PARTICLES; ENERGY RANGE; FERMIONS; GEV RANGE; HADRONS; INCLUSIVE INTERACTIONS; INELASTIC SCATTERING; INFORMATION; INTERACTIONS; LEPTON REACTIONS; LEPTON-BARYON INTERACTIONS; LEPTON-HADRON INTERACTIONS; LEPTON-NUCLEON INTERACTIONS; LINEAR MOMENTUM; MATHEMATICAL MODELS; NUCLEAR REACTIONS; NUMERICAL DATA; ORIENTATION; PARTICLE INTERACTIONS; PARTICLE MODELS; PROCESSING; SCATTERING; SIMULATION; TARGETS

Optional Information

Collaborations
COMPASS Collaboration