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Author ORCID Identifier
N/A
AccessType
Open Access Dissertation
Document Type
dissertation
Degree Name
Doctor of Philosophy (PhD)
Degree Program
Physics
Year Degree Awarded
2018
Month Degree Awarded
February
First Advisor
Carlo Dallapiccola
Second Advisor
Ben Brau
Third Advisor
Michael Ramsey-Musolf
Fourth Advisor
Grant Wilson
Subject Categories
Elementary Particles and Fields and String Theory
Abstract
A search for long-lived, massive particles decaying into dimuon pairs, in 32.9 fb-1 of data analyzed from the ATLAS detector is presented. Two signal models are considered: GGM SUSY, where the long lived particle mass is between 300-1000 GeV, and the dark photon model, where the ZD mass is between 20-60 GeV. An excess over the predicted background is observed in the GGM channel, however the angular/kinematic distributions of the excess vertices are consistent with a detec- tor/conditions related issue. A modified selection is used for the GGM channel which increases the signal sensitivity. 95% confidence level (CL) upper limits on the signal cross sections times branching fraction are set as a function of cτ for both benchmark models. The cτ limits for the GGM channel extend from 2.57-1050 cm, and the cτ limit for the ZD channel extends from 0.32-1572 cm. 95% CL upper limits on the ZD cross section are also set in the coupling-cτ plane, for a range of BF(H→ ZDZD).
DOI
https://doi.org/10.7275/11258826.0
Recommended Citation
Bernard, Nathan, "Search for long-lived, massive particles decaying into dimuon vertices in pp collisions at 13 TeV with the ATLAS detector at the LHC" (2018). Doctoral Dissertations. 1154.
https://doi.org/10.7275/11258826.0
https://scholarworks.umass.edu/dissertations_2/1154