Off-campus UMass Amherst users: To download campus access dissertations, please use the following link to log into our proxy server with your UMass Amherst user name and password.

Non-UMass Amherst users: Please talk to your librarian about requesting this dissertation through interlibrary loan.

Dissertations that have an embargo placed on them will not be available to anyone until the embargo expires.

Author ORCID Identifier



Open Access Dissertation

Document Type


Degree Name

Doctor of Philosophy (PhD)

Degree Program


Year Degree Awarded


First Advisor

Stephane Willocq

Subject Categories

Elementary Particles and Fields and String Theory


A search is conducted for non-resonant new phenomena in the dimuon final states, originating from either contact interactions or large extra spatial dimensions. The proton-proton collision data recorded by the ATLAS detector at the LHC in 2012 at √s = 8 TeV, corresponding to an integrated luminosity of 20.5 fb-1, is used. The dimuon invariant mass spectrum is a discriminating variable in both searches, with the contact interaction search additionally utilizing the dimuon forward-backward asymmetry. No significant deviations from the Standard Model expectation are observed. Lower limits are set on the new physics parameters of interest at 95% credibility level. For qqμμ contact interactions, lower limits are set on the contact interaction scale Λ between 11.8 and 20.5 TeV. Lower limits are also set on the string scale MS for large extra spatial dimensions, from 2.8 TeV to 4.4 TeV. Results from the muon channel are combined with the electron channel to further extend the range of the lower limits on the contact interaction scale Λ to 15.4-26.3 TeV and the range of the lower limits on the string scale MS to 3.2-5.0 TeV. The lower limits both on Λ and MS are the most stringent limits to date.