Thesis (Ph. D.)--University of Wisconsin--Madison, 1981. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 293-310).

Thesis (Ph.D.) -- Virginia Commonwealth University, 2005. / Title from title-page of electronic thesis. Prepared for: Dept. of Mechanical Engineering. Bibliography: p. 112-123.

Tübingen, Universiẗat, Diss., 2001.

Thesis (Ph. D.)--University of Texas at Austin, 2006. / Vita. Includes bibliographical references.

Ph.D.

Thesis (Ph. D.)--University of Chicago, Dept. of Physics, March 2001. / Includes bibliographical references. Also available on the Internet.

The standard model of particle physics can explain most measurements of elementary particle properties and interactions performed to date. However, it does not naturally explain the relatively light Higgs boson mass or the existence of small neutrino masses, and has no explanation for the dark matter observed in the universe. Many extensions to the standard model have been proposed to attempt to address these questions, and several predict the existence of heavy charged gauge bosons, usually referred to as W' bosons. The Large Hadron Collider at CERN is the largest and most powerful particle accelerator in the world and offers the opportunity to search for W' bosons using the CMS experiment, a large multi-purpose particle detector. Results are presented from a search for a W' boson produced in proton-proton collisions at a center of mass energy sqrt(s)=8 TeV and decaying into a top and a bottom quark, using a dataset collected by the CMS experiment corresponding to an integrated luminosity of 19.5 fb^-1. Various models of W' boson production are studied by allowing for an arbitrary combination of left- and right-handed fermionic couplings. The analysis is based on the detection of events with an electron or muon, jets and missing transverse energy in the final state. No evidence for W' boson production is found and 95% confidence level upper limits are obtained on the production cross section for several mass hypotheses and compared to theoretical predictions. For W' bosons with purely right-handed couplings, and for those with left-handed couplings when ignoring interference effects, the observed 95% confidence level limit on the W' boson mass is M(W')>2.05 TeV. These are the most stringent limits obtained to date in this channel.

abstract: Cosmology, carrying imprints from the entire history of the universe, has emerged as a precise observational science over the past 30 years. It can probe physics beyond the Standard Model at energy scales much higher than the weak scale. This thesis reports on some important probes of beyond standard model physics derived in a cosmological setting - (I) It is shown that primordial gravitational waves left over from inflation carry unique detectable CMB signatures for neutrino masses, axions and any other relativistic species that may have been present. (II) Higgs Inflation, the most popular and compelling inflation model with a higgs boson is studied next and it is shown that quantum effects have so far been incorrectly incorporated. A spurious gauge ambiguity arising from quantum effects enters the canonical prediction for observables in Higgs Inflation that must be addressed. (III) A new novel mechanism for generating the observed baryon asymmetry of the universe via decaying gravitinos is proposed. If the Supersymmetry (SUSY) breaking scale is high, then in the presence of R-parity violation, gravitinos can successfully reproduce the baryon asymmetry and evade all low energy constraints. (IV) The final chapter reports on a new completely general analysis of simplified models used in direct detection of dark matter. This is useful to explore what high energy physics constraints can be obtained from direct detection experiments. / Dissertation/Thesis / Doctoral Dissertation Physics 2015

abstract: The identity and origin of dark matter is one of the more elusive mysteries in the fields of particle physics and cosmology. In the near future, direct dark matter detectors will offer a chance at observing dark matter non-gravitationally for the first time. In this thesis, formalisms are developed to analyze direct detection experiments and to quantify the extent to which properties of the dark matter can be determined. A range of non-standard assumptions about the dark matter are considered, including inelastic scattering, isospin violation and momentum dependent scattering. Bayesian inference is applied to realistic detector configurations to evaluate parameter estimation and model selection ability. A complete set of simplified models for spin-0, spin-1/2 and spin-1 dark matter candidates are formulated. The corresponding non-relativistic operators are found, and are used to derive observational signals for the simplified models. The ability to discern these simplified models with direct detection experiments is demonstrated. In the near future direct dark matter detectors will be sensitive to coherent neutrino scattering, which will limit the discovery potential of these experiments. It was found that eleven of the fourteen non-relativistic operators considered produce signals distinct from coherent scattering, and thus the neutrino background does not greatly affect the discovery potential in these cases. / Dissertation/Thesis / Doctoral Dissertation Physics 2016

abstract: The work presented in this dissertation examines three different nonequilibrium particle physics processes that could play a role in answering the question “how was the particle content of today’s universe produced after the big bang?” Cosmic strings produced from spontaneous breaking of a hidden sector $U(1)_{\rm X}$ symmetry could couple to Standard Model fields through Higgs Portal or Kinetic Mixing operators and radiate particles that contribute to the diffuse gamma ray background. In this work we calculate the properties of these strings, including finding effective couplings between the strings and Standard Model fields. Explosive particle production after inflation, known as preheating, would have produced a stochastic background of gravitational waves (GW). This work shows how the presence of realistic additional fields and interactions can affect this prediction dramatically. Specifically, it considers the inflaton to be coupled to a light scalar field, and shows that even a very small quartic self-interaction term will reduce the amplitude of the gravitational wave spectrum. For self-coupling $\lambda_{\chi} \gtrsim g^2$, where $g^2$ is the inflaton-scalar coupling, the peak energy density goes as $\Omega_{\rm GW}^{(\lambda_{\chi})} / \Omega_{\rm GW}^{(\lambda_{\chi}=0)} \sim (g^2/\lambda_{\chi})^{2}$. Finally, leptonic charge-parity (CP) violation could be an important clue to understanding the origin of our universe's matter-antimatter asymmetry, and long-baseline neutrino oscillation experiments in the coming decade may uncover this. The CP violating effects of a possible fourth ``sterile" neutrino can interfere with the usual three neutrinos; this work shows how combinations of various measurements can help break those degeneracies. / Dissertation/Thesis / Doctoral Dissertation Physics 2016