Description
- Abstract:
- The Standard Model (SM) of particle physics has proven to be a very successful theory in explaining many experimental observations involving electroweak and strong interactions. Nevertheless, the SM is an incomplete theory as it does not describe gravity. The inclusion of gravity requires a theory that is valid up to the Planck scale. If no new physics resides above the SM, running the SM up to the Planck scale leads to divergence terms in the Higgs mass calculation. With the observation of the Higgs boson at 125 GeV, this can only be achieved by a large amount of fine-tuning to the SM parameters, known as the Hierarchy problem. Thus, many theories Beyond the Standard Model (BSM) were proposed. This thesis presents searches for new elementary particles through their decays to tau leptons using the data collected by the Compact Muon Solenoid (CMS). First, a search for a massive Higgs boson is presented in the context of the Minimal Supersymmetry Standard Model (MSSM). The MSSM tackles the Hierarchy problem by predicting super partners to the SM particles. These new particles introduce extra correction terms in the Higgs mass calculation and automatically cancel out the diverging terms which need fine-tuning. Here, the decay channel of H → hh → 𝜏𝜏bb is studied with a tau, anti-tau lepton pair and a b, anti-b quark pair as the final state. The second part of the thesis focuses on the search for a new neutral gauge boson, denoted as Z’. Many BSM theories, ranging from Grand Unification Theories, which hope to unite the strong and electroweak interactions, to the Little Higgs Model, all predict the presence of extra gauge bosons. In this thesis, we present the search for the Z’ boson through its decay into a pair of tau, anti-tau leptons in the context of the Sequential Standard Model.
- Notes:
- Thesis (Ph. D.)--Brown University, 2017
Access Conditions
- Rights
- In Copyright
- Restrictions on Use
- Collection is open for research.
Citation
Mao, Zaixing,
"Search for New Physics with Tau Lepton Final States"
(2017).
Physics Theses and Dissertations.
Brown Digital Repository. Brown University Library.
https://doi.org/10.7301/Z0N58JVJ
