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|Title: ||Searching for deviations from the standard model in top decays and prompt eμ events with the ATLAS detector|
|Authors: ||Patel, Nikhul|
|Issue Date: ||8-May-2014|
|Publisher: ||University of Sydney|
School of Physics
|Abstract: ||This thesis demonstrates two different approaches to searching for inconsistencies between the SM expectation and 4.6 fb-1 of proton-proton collision data, collected by ATLAS in 2011, at a centre of mass energy of 7 TeV.
The charged Higgs analyses involve determining whether-or-not there exists an excess of top quarks decaying to tau leptons, and whether this is compatible with the hypothesised existence of a light charged Higgs boson.
The focus is on trying to separate the possible charged Higgs signal events produced via top quark pairs from their SM counterparts, and ensuring that the SM backgrounds and their uncertainties are determined accurately in order to maximise the sensitivity to a potential signal.
Ultimately no signal is observed and an upper limit on the branching ratio t->bH+ is set ranging from 1-5% over a charged Higgs mass range of 90-160 GeV, assuming a charged Higgs decaying exclusively to a tau lepton and neutrino.
The second approach, taken in an inclusive dilepton analysis, was to determine and implement a method to test the agreement with the SM over the much larger phase space set by a minimal selection of an electron and oppositely charged muon.
A goodness-of-fit test of data against the SM expectation is conducted over the transverse missing energy and jets multiplicity parameter space that naturally separates the main processes that produce such eμ final states. No statistically significant deviation from the SM is observed over the parameter space considered.
The work presented in this thesis provides no statistically significant evidence for the inconsistency of the SM with data collected by ATLAS in 2011 in either opposite sign eμ events, or the rate of top quark decay to a tau final state.|
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|Rights and Permissions: ||The author retains copyright of this thesis. It may only be used for the purposes of research and study. It must not be used for any other purposes and may not be transmitted or shared with others without prior permission.|
|Type of Work: ||PhD Doctorate|
|Type of Publication: ||Doctor of Philosophy Ph.D.|
|Appears in Collections:||Sydney Digital Theses (University of Sydney Access only)|
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|patel_nd_thesis.pdf||PhD thesis||9.47 MB||Adobe PDF|
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