The gluon polarisation in the nucleon has been determined by detecting charm production via D0 meson decay to charged K and π in polarised muon scattering off a longitudinally polarised deuteron target. The data were taken by the COMPASS Collaboration at CERN between 2002 and 2006 and correspond to an integrated luminosity of 2.8 fb−1. The dominant underlying process of charm production is the photon–gluon fusion to a_(c barc) pair. A leading order QCD approach gives an average gluon polarisation of <Δg/g>_x=−0.49±0.27(stat)±0.11(syst) at a scale μ^2≈13 (GeV/c)^2 and at an average gluon momentum fraction <x>≈0.11. The longitudinal cross-section asymmetry for D0 production is presented in bins of the transverse momentum and the energy of the D0 meson.

Gluon polarisation in the nucleon and longitudinal double spin asymmetries from open charm muoproduction

BRADAMANTE, FRANCO;BRESSAN, Andrea;DALLA TORRE, SILVIA;DUIC, VENICIO;GIORGI, MARCELLO;LEVORATO, STEFANO;MARTIN, ANNA;PESARO, GIULIA;SCHIAVON, PAOLO;SOZZI, FEDERICA;TAKEKAWA, STEFANO;TESSARO, SUSANNA;
2009

Abstract

The gluon polarisation in the nucleon has been determined by detecting charm production via D0 meson decay to charged K and π in polarised muon scattering off a longitudinally polarised deuteron target. The data were taken by the COMPASS Collaboration at CERN between 2002 and 2006 and correspond to an integrated luminosity of 2.8 fb−1. The dominant underlying process of charm production is the photon–gluon fusion to a_(c barc) pair. A leading order QCD approach gives an average gluon polarisation of <Δg/g>_x=−0.49±0.27(stat)±0.11(syst) at a scale μ^2≈13 (GeV/c)^2 and at an average gluon momentum fraction ≈0.11. The longitudinal cross-section asymmetry for D0 production is presented in bins of the transverse momentum and the energy of the D0 meson.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11368/2293995
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