{"id":{"repo_id":"freiburg-diss","oai_identifier":"oai:freidok.uni-freiburg.de:2282"},"canonical_url":"https://search.dev.ndltd.org/etd/freiburg-diss/oai:freidok.uni-freiburg.de:2282","repository":{"repo_id":"freiburg-diss","name":"University of Freiburg","base_url":"https://freidok.uni-freiburg.de/oai/oai2.php"},"display":{"title":"Determination of the gluon polarisation in the nucleon using hadron pairs with high transverse momentum at COMPASS","abstract":"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.","abstract_html":"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. &lt;br&gt; &lt;br&gt;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. &lt;br&gt;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.","abstract_has_math":false,"creators":["Hedicke, Sonja"],"institution":null,"degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":["Königsmann, Kay"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":null,"date_issued":"","date_published":null,"updated_at":"2026-07-24T02:22:40Z","subjects":["Gluonpolarisation","polarisierte tiefinelastische Streuung","Helizitätsasymmetrie","Hadronpaare mit hohem Transversalimplus","COMPASS","gluon polarisation","polarised deep-inelastic scattering","helicity asymmetry","hadron pairs with high transverse momentum"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://freidok.uni-freiburg.de/data/2282","outbound_label":"Repository record","outbound_source":"source_url"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Königsmann, Kay"]},{"key":"dc:creator","label":"Author","values":["Hedicke, Sonja"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:type","label":"Dc Type","values":["DoctoralThesis"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Gluonpolarisation","polarisierte tiefinelastische Streuung","Helizitätsasymmetrie","Hadronpaare mit hohem Transversalimplus","COMPASS","gluon polarisation","polarised deep-inelastic scattering","helicity asymmetry","hadron pairs with high transverse momentum"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["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.","Der Spin des Nukleons ist der Untersuchungsgegenstand zahlreicher Experimente. Der Helizitätsbeitrag der Quarks zum Spin des Nukleons ist gut erforscht, allerdings sind die Beiträge der Gluonen und des Bahndrehimpluses weitgehend unbekannt. <br>Diese Arbeit widmet sich der Messung der Gluonpolarisation im Nukleon. Die Analyse basiert auf den Daten, die in den Jahren 2002 und 2003 mit dem COMPASS-Experiment am CERN aufgezeichnet wurden. Aus diesen Daten der tiefinelastischen Myon-Deuteron-Streuung werden Ereignisse ausgewählt, die zwei Hadronen mit grossem Transversalimpuls (pt) enthalten. <br>Diese Auswahl von \"high-pt\" Hadronpaaren besteht zu einen grossen Anteil aus Photon-Gluon-Fusions-Ereignissen, die einen direkten Zugang zu den Gluonen im Nukleon erlauben. Die Forderung nach Hadronpaaren mit hohem Transversalimplus führt aber nicht dazu, dass Untergrundereignisse durch Streuung am Quark <br>vollständig unterdrückt werden. Deswegen wird eine Monte Carlo-Simulation durchgeführt um die Anteile von Photon-Gluon-Fusions-Ereignissen und Untergrund zu bestimmen. Unter Berücksichtigung dieser Untergrundbeiträge wird die <br>Gluonpolarisation Delta G/G aus der Asymmetrie der helizitätsabhängigen Wirkungsquerschnitte der \"high-pt\" Ereignisse bestimmmt."]},{"key":"dc:format.medium","label":"Dc Format Medium","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Determination of the gluon polarisation in the nucleon using hadron pairs with high transverse momentum at COMPASS","Bestimmung der Gluonpolarisation im Nukleon unter Verwendung von Hadronpaaren mit hohem Transversalimpuls bei COMPASS"]}]}],"canonical_facts":{"dc:contributor":["Königsmann, Kay"],"dc:creator":["Hedicke, Sonja"],"dc:description.abstract":["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.","Der Spin des Nukleons ist der Untersuchungsgegenstand zahlreicher Experimente. Der Helizitätsbeitrag der Quarks zum Spin des Nukleons ist gut erforscht, allerdings sind die Beiträge der Gluonen und des Bahndrehimpluses weitgehend unbekannt. <br>Diese Arbeit widmet sich der Messung der Gluonpolarisation im Nukleon. Die Analyse basiert auf den Daten, die in den Jahren 2002 und 2003 mit dem COMPASS-Experiment am CERN aufgezeichnet wurden. Aus diesen Daten der tiefinelastischen Myon-Deuteron-Streuung werden Ereignisse ausgewählt, die zwei Hadronen mit grossem Transversalimpuls (pt) enthalten. <br>Diese Auswahl von \"high-pt\" Hadronpaaren besteht zu einen grossen Anteil aus Photon-Gluon-Fusions-Ereignissen, die einen direkten Zugang zu den Gluonen im Nukleon erlauben. Die Forderung nach Hadronpaaren mit hohem Transversalimplus führt aber nicht dazu, dass Untergrundereignisse durch Streuung am Quark <br>vollständig unterdrückt werden. Deswegen wird eine Monte Carlo-Simulation durchgeführt um die Anteile von Photon-Gluon-Fusions-Ereignissen und Untergrund zu bestimmen. Unter Berücksichtigung dieser Untergrundbeiträge wird die <br>Gluonpolarisation Delta G/G aus der Asymmetrie der helizitätsabhängigen Wirkungsquerschnitte der \"high-pt\" Ereignisse bestimmmt."],"dc:format.medium":["application/pdf"],"dc:subject":["Gluonpolarisation","polarisierte tiefinelastische Streuung","Helizitätsasymmetrie","Hadronpaare mit hohem Transversalimplus","COMPASS","gluon polarisation","polarised deep-inelastic scattering","helicity asymmetry","hadron pairs with high transverse momentum"],"dc:title":["Determination of the gluon polarisation in the nucleon using hadron pairs with high transverse momentum at COMPASS","Bestimmung der Gluonpolarisation im Nukleon unter Verwendung von Hadronpaaren mit hohem Transversalimpuls bei COMPASS"],"dc:type":["DoctoralThesis"]},"updated_at":"2026-07-24T02:22:40Z"}