Determination of the gluon polarisation in the nucleon using hadron pairs with high transverse momentum at COMPASS

The spin of the nucleon is the topic of many past and present experiments. While the quark helicity contribution to the nucleon has been measured, the contributions from gluons and orbital angular momentum are not constrained. <br> <br>This thesis is dedicated to the determination of the gluon polarisation in the nucleon. The analysis is based on the data taken by the COMPASS experiment at CERN during the years 2002 and 2003. From deep inelastic muon-deuteron scattering data, obtained with a polarised muon beam of 160 GeV on a polarised ^6LiD target, events with two hadrons with large transverse momentum (pt) have been selected. <br>This sample of high-pt hadron events contains an enriched fraction of photon-gluon fusion events that directly probe the gluons inside the nucleon. The requirement of hadron pairs with large transverse momentum does not fully suppress background events. Therefore, a Monte Carlo simulation with LEPTO is used to evaluate the fraction of photon-gluon fusion to background events. Taking into account the background contributions from the Monte Carlo simulation, the gluon polarisation Delta G/G has been extracted from the helicity dependent cross section asymmetry of the high-pt sample.

Author dc:creator

• Hedicke, Sonja

Contributors dc:contributor

• Königsmann, Kay

• Gluonpolarisation
• polarisierte tiefinelastische Streuung
• Helizitätsasymmetrie
• Hadronpaare mit hohem Transversalimplus
• COMPASS
• gluon polarisation
• polarised deep-inelastic scattering
• helicity asymmetry
• hadron pairs with high transverse momentum

Repository record source_url

https://freidok.uni-freiburg.de/data/2282

OAI identifier oai:identifier

oai:freidok.uni-freiburg.de:2282