Phenomenological studies in astronomy and collider physics
Abstract
In Part I, we investigate the evolution of the population of Active Galactic Nuclei (AGNs) on cosmological time scales. We use the largest, most uniform, and one of the most spectroscopically complete Chandra sample to date to construct hard (2-8 keV) rest-frame X-ray luminosity functions (HXLFs) of spectroscopically identified AGNs to z ∼ 5. In addition, we use a 2-8 keV local sample selected by the very hard (14-195 keV) SWIFT 9-month Burst Alert Telescope (BAT) survey to construct the local 2-8 keV HXLF. In Part II, we study various signatures of New Physics models at collider experiments. We begin by presenting leading-order (LO) cross sections for the production of three top quarks ( ttt ?,ttt ) at the Large Hadron Collider (LHC) and we give examples of two new physics models which have a significant enhancement to this channel. With efficient identification and reconstruction of the top quarks, we demonstrate that the triple-top signal could potentially provide evidence for new physics at the LHC. In Part II we also present a benchmark in the parameter space of the Next-to-minimal Super-symmetric Standard Model (NMSSM) that provides for a dramatic multilepton signal and no jets containing 5 or more leptons resulting from the cascade decays of the third lightest neutralino, [Special characters omitted.] c03, and the lightest chargino, [Special characters omitted.] c±1, via light charged sleptons. This is a very clean signal with almost no standard model (SM) background. We demonstrate the detectability of this signal at the LHC and, in addition, show that simple measurements of the mass differences of heavy particles in the decay chains can be made by looking at kinematic edges in the invariant mass distributions 2, 3, and 4 leptons.
- Publication:
-
Ph.D. Thesis
- Pub Date:
- 2011
- Bibcode:
- 2011PhDT........11Y