Examining Extra Neutral Gauge Bosons in Non-Universal Models and Exploring the Phenomenology of the Bestest Little Higgs Model at the LHC.

摘要

This thesis expands upon the literature in two distinct areas - exploring properties of extra neutral gauge boson (Z') observables, and exploring the phenomenology of the Bestest Little Higgs model at the Large Hadron Collider.;In the second Part, the heavy quark sector of the Bestest Little Higgs model is explored. With an integrated luminosity of 1.14 fb-1 at the LHC (7 TeV), the discovery reach for new heavy top quarks in the model is found to be above 350 GeV for two sample regions of parameter space. This is lower than most experimental studies suggest since the lightest heavy top partners in the Bestest Little Higgs model decay to a combination of bW, tZ and th final states, rather than to a singular decay mode. Expanding on this, measurements of the masses of the heavy top partners, heavy bottom quark and exotic +5/3 charge quark are simulated in the bb¯W+W - and tt¯W+W - final states to explore the capability of the LHC experiments to determine the Yukawa coupling parameters, which are necessary for understanding the degree of cancellation for the top loop contribution to the Higgs mass. With an integrated luminosity of 100 fb-1 for 14 TeV collisions, it should be possible to measure the masses of either the T 6 and T5 quarks or the T 6 and the B quarks, the combinations of which give insight to different Yukawa parameters, respectively. Measuring all heavy quark states will prove to be difficult without a significant increase in luminosity over the design goal of 100 fb-1. The heaviest top partner states are suppressed by the available phase space and decay primarily to non-Standard Model final states, which results in an event rate that is too low to be seen at 100 fb-1 of integrated luminosity.;In the first Part, it is shown that two well known Z' observables, the centre-edge asymmetry and forward-backward asymmetry, can be calculated using only the pseudorapidity values of the final state decay products. The benefit of this method is that pseudorapidity can be measured very precisely, which reduces systematic uncertainties that arise from compounding errors in calculating the full kinematics of each event. The forward-backward asymmetry of hadronic final states with large DeltaR is also simplified, as the pseudorapidity of the centroid of such fat jets can be used. Additionally, this thesis explores the application of cross section ratios (Z' → tt¯, Z' → bb¯, and Z' → r +r- to Z' → mu +mu-) to exploring the class of models with non-universal couplings, such as Topcolor and Technicolor models. It is clear that uniquely identifying non-universal couplings necessarily requires measuring decays of the Z' to third generation final states.