Search for Contact Interactions in the Dimuon Channel in $pp$ Collisions at $$\sqrt{s} = 7$$ TeV at CMS

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 2012

DOI:https://doi.org/10.2172/1127914· OSTI ID:1127914

Gollapinni, Sowjanya ^[1]

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1. Wayne State Univ., Detroit, MI (United States)

The standard model fails to explain the variety of observed quark and lepton avors 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% con dence level are set on the compositeness energy scale , 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 signi cantly.

• Research Organization: Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
• Sponsoring Organization: USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
• DOE Contract Number: AC02-07CH11359
• OSTI ID: 1127914
• Report Number(s): CERN-THESIS--2012-268; FERMILAB-THESIS--2012-28
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS