Identifying Supersymmetry at the CERN LHC and Indirect Dark Matter Detection Experiments.

Supersymmetry;LHC;Dark Matter;Physics;Science;Physics

Grajek, Phillip R.Pierce, Aaron Thomas ;

University of Michigan

关键词: Supersymmetry;    LHC;    Dark Matter;    Physics;    Science;    Physics;   

Others  :  https://deepblue.lib.umich.edu/bitstream/handle/2027.42/63818/elementl_1.pdf?sequence=1&isAllowed=y

瑞士|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

Supersymmetry (SUSY) remains the most well-motivated scenario for new physicsbeyond the Standard Model. There is strong reason to expect that if nature is supersymmetric it will be observed at the LHC. Consequently, searches for SUSY areamong the primary tasks of the LHC program. However, much of this work focuseson scenarios such as mSUGRA, which include many simplifying assumptions. It isnecessary, therefore, to consider the broader SUSY parameter space, and explore theimplications of various other model choices on the spectrum of possible experimental signatures. This thesis addresses this phenomenologically challenging problem.We present several studies that examine the relationship between various SUSYscenarios and experimental phenomena, and introduce new techniques to extractmeaningful information about fundamental parameters. First, we discuss identification of multiple top quark production from gluino decay at the LHC. We find that4-top production can be discovered in excess of Standard Model backgrounds with∼ 500 pb^−1 of data. We argue that statistical reconstruction of this scenario is extremely difficult due to large combinatorical uncertainty. We demonstrate a novelapproach whereby information about the gluino decay fraction into top quarks maybe extracted with low luminosity, thus providing early evidence for multi-top produc-tion. Next, we investigate the problem of identifying gaugino mass unification fromLHC measurements. We consider mirage-mediation models, where gaugino massuniversality is controlled by a single parameter α (α → 0 gives the universal limit).We show that that by utilizing a χ^2 -like metric on the signature space it is possibleto detect non-universality to α ≃ 0.3 with only a few fb^−1 of data for the majorityof the parameter space. Finally, we examine the excess positron flux reported bythe HEAT, AMS, and PAMELA experiments. We argue that annihilation of light(200 GeV), non-thermally produced wino-like LSP WIMPs can explain the excesses.However we find this candidate does not convincingly model the recent PAMELAmeasurements if traditional astrophysical propagation parameters are assumed.