145,164 research outputs found
Gluon polarisation from high transverse momentum hadron pairs production (COMPASS)
A new preliminary result of a gluon polarisation \Delta G/G obtained
selecting high transverse momentum hadron pairs in DIS events with Q^2>1
(GeV/c)^2 is presented. Data has been collected by COMPASS at CERN during the
2002-2004 years. In the extraction of contributions coming from
the leading order and QCD processes are taken into account. A new
weighting method based on a neural network approach is used. Also a preliminary
result of \Delta G/G for events with Q^2<1 (GeV/c)^2 is presented.Comment: Advanced Studies Institute On Symmetries And Spin (SPIN-Praha-2008)
20-26 Jul 2008, Prague, Czech Republic. The proceedings of the ASI will be
published in The European Physical Journal Special Topics (EJP ST) Serie
Compass Results on Gluon Polarisation from High pT hadron pairs
One of the goals of the COMPASS experiment is the determination of the gluon
polarisation \Delta G/G, for a deep understanding of the spin structure of the
nucleon. In DIS the gluon polarisation can be measured via the
Photon-Gluon-Fusion (PGF) process, identified by open charm production or by
selecting high p_T hadron pairs in the final state. The data used for this work
were collected by the COMPASS experiment during the years 2002-2004, using a
160 GeV naturally polarised positive muon beam scattering on a polarised
nucleon target. A new preliminary result of the gluon polarisation \Delta G/G
from high p_T hadron pairs in events with Q^2>1 (GeV/c)^2 is presented. In
order to extract \Delta G/G, this analysis takes into account the leading
process \gamma q contribution together with the PGF and QCD Compton processes.
A new weighted method based on a neural network approach is used. A preliminary
\Delta G/G result for events from quasi-real photoproduction (Q^2<1 (GeV/c)^2)
is also presented.Comment: prepared for the proceedings of the DSPIN09 - XIII Workshop on High
Energy Spin Physics, Dubna, Russia, September 1 - 5, 200
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