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New results on quark helicity distributions and gluon polarization from the COMPASS experiment at CERN
The new results on quark helicity distributions and on the gluon polarization DG=G from the COMPASS experiment will be presented. COMPASS is a DIS experiment using polarized muons with an energy of 160 GeV scattered off polarized deuteron and proton targets. Quark helicity distributions are obtained...
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Lenguaje: | eng |
Publicado: |
2009
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Materias: | |
Acceso en línea: | http://cds.cern.ch/record/1283249 |
Sumario: | The new results on quark helicity distributions and on the gluon polarization DG=G from the COMPASS experiment will be presented. COMPASS is a DIS experiment using polarized muons with an energy of 160 GeV scattered off polarized deuteron and proton targets. Quark helicity distributions are obtained from inclusive and semi-inclusive reactions from the 2002-2004 and 2006 deuteron data and from the 2007 proton data. The gluon polarization DG=G is determined from photon-gluon fusion (PGF) events. Two methods based on LO QCD approximation are used to extract PGF events: the selection of open-charm events via the observation of D and D0 mesons or of a pair of high-pT hadrons. The open-charm result is obtained from the 2002- 2004 and 2006 data and it is updated with additional charm channels contributions. For these contributions a new method of the signal strength parameterization based on a neural network classification is used. The high-pT hadron pair result is obtained from the 2002-2004 data using a new method of accounting for background processes. European |
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