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SEARCH FOR CONTACT INTERACTIONS IN THE DIMUON CHANNEL IN P-P COLLISIONS AT $\sqrt{s}$ = 7 TeV AT CMS

The standard model fails to explain the variety of observed quark and lepton flavors and their masses suggesting that there might exist a more fundamental basis. If quarks and leptons are composite particles made up of more basic constituents, a new physics interaction in the form of a four-ferm...

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Detalles Bibliográficos
Autor principal: Gollapinni, Sowjanya
Lenguaje:eng
Publicado: ProQuest/UMI Publishing 2012
Materias:
Acceso en línea:http://cds.cern.ch/record/1519119
Descripción
Sumario:The standard model fails to explain the variety of observed quark and lepton flavors and their masses suggesting that there might exist a more fundamental basis. If quarks and leptons are composite particles made up of more basic constituents, a new physics interaction in the form of a four-fermion contact interaction arises between them. Experimentally the signal is manifest as a deviation from the standard model prediction in the high-mass tail for the invariant mass distribution of the opposite-sign dimuon pairs. The Large Hadron Collider accelerator at the Center for European Nuclear Research is built to explore new physics possibilities from proton-proton collisions occurring at the world's highest center-of-mass energy. This thesis discusses in detail a search strategy for a new physics possibility based on a left-handed current model of contact interactions. Based on 5.3 fb$^{-1}$ of 2011 data as collected by the Compact Muon Solenoid detector, exclusion lower limits at 95\% confidence level are set on the compositeness energy scale $\Lambda$, for both destructive and constructive interferences of the new physics with the standard model Drell-Yan process. These limits form the most stringent limits to date and exceed the current published limits significantly.