Dark Matter Production Associated With a Heavy Quarkonium at B Factories

We investigate light dark matter production associated with a heavy quarkonium at B factories in a model-independent way by adopting the effective field theory approach for the interaction of dark matter with standard model particles. We consider the effective operators for the dark matter-heavy quark interaction, which are relevant to the production of dark matter associated with a heavy quarkonium. We calculate the cross sections for dark matter production associated with a J/psi or eta_c to compare with the standard model backgrounds. We set bounds on the energy scale of new physics for various effective operators and also obtain the corresponding limits for the dark matter-nucleon scattering cross sections for light dark matter with mass of the order of a few GeV.Comment: 13 pages, 5 figures, references adde

Scattering Amplitudes For All Masses and Spins

We introduce a formalism for describing four-dimensional scattering amplitudes for particles of any mass and spin. This naturally extends the familiar spinor-helicity formalism for massless particles to one where these variables carry an extra SU(2) little group index for massive particles, with the amplitudes for spin S particles transforming as symmetric rank 2S tensors. We systematically characterise all possible three particle amplitudes compatible with Poincare symmetry. Unitarity, in the form of consistent factorization, imposes algebraic conditions that can be used to construct all possible four-particle tree amplitudes. This also gives us a convenient basis in which to expand all possible four-particle amplitudes in terms of what can be called "spinning polynomials". Many general results of quantum field theory follow the analysis of four-particle scattering, ranging from the set of all possible consistent theories for massless particles, to spin-statistics, and the Weinberg-Witten theorem. We also find a transparent understanding for why massive particles of sufficiently high spin can not be "elementary". The Higgs and Super-Higgs mechanisms are naturally discovered as an infrared unification of many disparate helicity amplitudes into a smaller number of massive amplitudes, with a simple understanding for why this can't be extended to Higgsing for gravitons. We illustrate a number of applications of the formalism at one-loop, giving few-line computations of the electron (g-2) as well as the beta function and rational terms in QCD. "Off-shell" observables like correlation functions and form-factors can be thought of as scattering amplitudes with external "probe" particles of general mass and spin, so all these objects--amplitudes, form factors and correlators, can be studied from a common on-shell perspective.Comment: 79 page

WHAT DO AUDITORS PROMISE THEIR GOVERNMENTAL AUDIT CLIENTS? WHAT DO GOVERNMENTAL AUDIT CLIENTS WANT? AUDIT PROPOSAL EVIDENCE FROM GOVERNMENTAL AUDIT PROCUREMENT PROCESSES

This dissertation, consisting of two studies, analyzes a dataset of audit proposals to investigate auditors’ impression management strategies and audit procurement quality in the public sector. Text based analytic methods are employed to examine the content of audit proposals, which were submitted for government audit engagements in fifteen states. The first study investigates auditors\u27 marketing language and hypothesizes that CPA firms will project a cooperative, non-independent image in audit proposals to impress potential clients. The results suggest that CPA firms, especially larger ones, project a persona of a cooperative and trustworthy service provider than to present themselves as independent auditors. In addition, CPA firms self-portray more independence when client management is involved in a procurement process compared to when an independent state audit agency selects the auditor. Responding to the PCAOB\u27s (2013) concern about auditors\u27 commercial interests and marketing materials, the findings suggest that CPA firms’ marketing language may threaten perceived auditor independence and thus are important to regulators, practitioners, and decision makers. The second study examines the association between auditor selection and perceived audit service qualities in audit proposals. Based on agency theory and prior research, this study predicts that government clients will choose an auditor whose audit proposal reflects more perceived audit quality attributes and that this association will be stronger for states with higher political competition or lower perceived risk of corruption. The results indicate that government clients tend to select an auditor who emphasizes competence, is a predecessor auditor, and, is less expensive. The findings provide insights into governmental audit procurement practices and the determinants of auditor selection decisions in the public sector. The dissertation contributes to the literature by creating a new, unexplored dataset of audit proposals, developing and validating linguistic categories related to the concepts of auditor independence, relationship marketing, and competence, and exploring potential threat of audit firms’ marketing materials to the appearance of auditor independence