The mass hierarchy problem associated with the standard model suggests that there might be more fundamental particles in nature. If quarks and leptons have substructures, known as preons, the manifestation of compositeness can be a four-fermion contact interaction. The experimental signal for contact interactions is a non-resonant enhancement of the number of events in the high-mass region of the dimuon mass spectrum. This dissertation describes a detailed search strategy for contact interactions using the Compact Muon Solenoid experiment. The dimuon mass spectrum above 300 GeV has been studied using the data collected in 2012 at sqrt(s) = 8 TeV corresponding to an integrated luminosity of 20.6 fb-1. The comparison of the observed mass spectrum with fully simulated Monte Carlo predictions for contact interactions in the context of the left-left isoscalar model with compositeness energy scale shows no signicant deviation from the standard model predictions. Exclusion lower limits are placed on Lambda of 14.8 TeV and 12.4 TeV at a 95 % condence level for constructive and destructive interference, respectively. The limits obtained from the study represent the most stringent limits to date.
","abstract_html":"<p>The mass hierarchy problem associated with the standard model suggests that there might be more fundamental particles in nature. If quarks and leptons have substructures, known as preons, the manifestation of compositeness can be a four-fermion contact interaction. The experimental signal for contact interactions is a non-resonant enhancement of the number of events in the high-mass region of the dimuon mass spectrum. This dissertation describes a detailed search strategy for contact interactions using the Compact Muon Solenoid experiment. The dimuon mass spectrum above 300 GeV has been studied using the data collected in 2012 at sqrt(s) = 8 TeV corresponding to an integrated luminosity of 20.6 fb-1. The comparison of the observed mass spectrum with fully simulated Monte Carlo predictions for contact interactions in the context of the left-left isoscalar model with compositeness energy scale shows no signicant deviation from the standard model predictions. Exclusion lower limits are placed on Lambda of 14.8 TeV and 12.4 TeV at a 95 % condence level for constructive and destructive interference, respectively. The limits obtained from the study represent the most stringent limits to date.</p>","abstract_has_math":false,"creators":["Kottachchi, Chamath"],"institution":null,"degree_name":"Ph.D.","degree_level":"Open Access Dissertation","degree_discipline":"Physics and Astronomy","degree_department":null,"school":null,"contributors":["Paul E. Karchin"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2014,"date_issued":"2014-01-01T08:00:00Z","date_published":"2014-01-01T08:00:00Z","updated_at":"2026-07-24T05:59:33Z","subjects":["CMS","Compositeness","Contact interaction","preons","Proton-Proton Collision","Quarks","Elementary Particles and Fields and String Theory","Physics"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://digitalcommons.wayne.edu/oa_dissertations/894","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Paul E. Karchin"]},{"key":"dc:creator","label":"Author","values":["Kottachchi, Chamath"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.available","label":"Dc Date Available","values":["2014-01-01T08:00:00Z"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Physics and Astronomy"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Open Access Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["CMS","Compositeness","Contact interaction","preons","Proton-Proton Collision","Quarks","Elementary Particles and Fields and String Theory","Physics"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://digitalcommons.wayne.edu/oa_dissertations/894"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["The mass hierarchy problem associated with the standard model suggests that there might be more fundamental particles in nature. If quarks and leptons have substructures, known as preons, the manifestation of compositeness can be a four-fermion contact interaction. The experimental signal for contact interactions is a non-resonant enhancement of the number of events in the high-mass region of the dimuon mass spectrum. This dissertation describes a detailed search strategy for contact interactions using the Compact Muon Solenoid experiment. The dimuon mass spectrum above 300 GeV has been studied using the data collected in 2012 at sqrt(s) = 8 TeV corresponding to an integrated luminosity of 20.6 fb-1. The comparison of the observed mass spectrum with fully simulated Monte Carlo predictions for contact interactions in the context of the left-left isoscalar model with compositeness energy scale shows no signicant deviation from the standard model predictions. Exclusion lower limits are placed on Lambda of 14.8 TeV and 12.4 TeV at a 95 % condence level for constructive and destructive interference, respectively. The limits obtained from the study represent the most stringent limits to date.
"]},{"key":"dc:title","label":"Title","values":["Search For Contact Interactions Using The Dimuon Mass Spectrum In P-P Collisions At Sqrt(s) = 8 Tev At Cms"]}]}],"canonical_facts":{"dc:contributor":["Paul E. Karchin"],"dc:creator":["Kottachchi, Chamath"],"dc:date.available":["2014-01-01T08:00:00Z"],"dc:description.abstract":["The mass hierarchy problem associated with the standard model suggests that there might be more fundamental particles in nature. If quarks and leptons have substructures, known as preons, the manifestation of compositeness can be a four-fermion contact interaction. The experimental signal for contact interactions is a non-resonant enhancement of the number of events in the high-mass region of the dimuon mass spectrum. This dissertation describes a detailed search strategy for contact interactions using the Compact Muon Solenoid experiment. The dimuon mass spectrum above 300 GeV has been studied using the data collected in 2012 at sqrt(s) = 8 TeV corresponding to an integrated luminosity of 20.6 fb-1. The comparison of the observed mass spectrum with fully simulated Monte Carlo predictions for contact interactions in the context of the left-left isoscalar model with compositeness energy scale shows no signicant deviation from the standard model predictions. Exclusion lower limits are placed on Lambda of 14.8 TeV and 12.4 TeV at a 95 % condence level for constructive and destructive interference, respectively. The limits obtained from the study represent the most stringent limits to date.
"],"dc:identifier":["https://digitalcommons.wayne.edu/oa_dissertations/894"],"dc:subject":["CMS","Compositeness","Contact interaction","preons","Proton-Proton Collision","Quarks","Elementary Particles and Fields and String Theory","Physics"],"dc:title":["Search For Contact Interactions Using The Dimuon Mass Spectrum In P-P Collisions At Sqrt(s) = 8 Tev At Cms"],"thesis:degree_discipline":["Physics and Astronomy"],"thesis:degree_level":["Open Access Dissertation"],"thesis:degree_name":["Ph.D."]},"updated_at":"2026-07-24T05:59:33Z"}