Physical Sciences and Mathematics Commons^™

Chasing New Physics: From Electroweak Baryogenesis To Dark Matter, Huaike Guo

Doctoral Dissertations

The origin of the baryon asymmetry in the universe and the nature of the dark matter remain mysteries and addressing these cosmological puzzles requires physics beyond the standard model. Electroweak baryogenesis remains a highly testable framework for explaining the baryon asymmetry and is employed in this work to study the capability of baryon generation for beyond standard model physics models and to explore new physics discovery potential in high energy and precision frontier. Weakly interacting massive particles as cold dark matter are also studied in this work featuring loop induced direct detection signals and novel nuclear responses within the recently …

Search For Long-Lived, Weakly Interacting Particles That Decay To Displaced Hadronic Jets In Proton-Proton Collisions At √S = 8 Tev With The Atlas Detector, Preema R. Pais

Doctoral Dissertations

Many new physics models predict the existence of neutral, weakly interacting, long-lived particles that can decay within the detector volume, producing a distinctive experimental signature. A search is performed for a pair of such particles, using proton-proton collision data at √s = 8 TeV collected by the ATLAS detector in 2012, corresponding to a total integrated luminosity of 20.3 fb^-1. Novel techniques are developed for the reconstruction of displaced decays to hadronic jets in the inner tracking detector and muon spectrometer. No significant deviation is found from the number of background events expected from Standard Model processes. The …

Prospects For Infrared Quantum Gravity: From Cosmology To Black Holes, Basem K. Mahmoud El-Menoufi

Doctoral Dissertations

Although perturbatively non-renormalizable, general relativity is a perfectly valid quantum theory at low energies. Treated as an effective field theory one is able to make genuine quantum predictions by applying the conventional rules of quantum field theory. The low energy degrees of freedom and couplings of quantum gravity are fully dictated by the symmetries of general relativity. To realize the full EFT treatment one has to supplement the theory with experimental input necessary to fix the Wilson coefficients of the most general Lagrangian. In spite of the fact that this is not feasible, one can still extract the leading quantum …

Hadron Physics In Tests Of Fundamental Symmetries, Chien Yeah Seng

Doctoral Dissertations

Low energy precision tests of fundamental symmetries provide excellent probes for the Beyond Standard Model Physics. Theoretical interpretations of these experiments often involve the application of non-perturbative Quantum Chromodynamics in the study of hadronic matrix elements that may either serve as signals of new physics or Standard Model backgrounds. In this work I present a series of studies on different hadronic matrix elements using various low-energy effective approaches to Quantum Chromodynamics, and discuss the impact of these studies on our knowledge of Standard Model and Beyond Standard Model physics.

Toward A Precision Measurement Of The Theta_13 Mixing Angle With The Double Chooz Detectors, Ben Thomas Rybolt

Doctoral Dissertations

Neutrinos are the most numerous and least understood particle in the universe. In the last few decades numerous experiments have been devoted to discovering their properties. The Double Chooz experiment was designed to make a precise measurement of θ₁₃ [theta 13], the neutrino mixing parameter which describes flavor oscillations governing short baselines. To accomplish this measurement, two identical neutrino detectors have been deployed at a near and far baseline outside two commercial nuclear reactors. The neutrino flux and spectrum at the near and far detector sites will determine the disappearance of anti-neutrinos created inside the reactors.

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