Physics Commons^™

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 …

On The Spin Evolution Of Isolated Pulsars, Oliver Quinn Hamil

Doctoral Dissertations

Neutron stars are the remnants of supernova explosions, and harbor the densest matter found in the universe. Because of their extreme physical characteristics, neutron stars make superb laboratories from which to study the nature of matter under conditions of extreme density that are not reproducible on Earth. The understanding of QCD matter is of fundamental importance to modern physics, and neutron stars provide a means of probing into the cold, dense region of the QCD phase diagram.

Isolated pulsars are rotating neutron stars that emit beams of electromagnetic radiation into space which appear like lighthouses to observers on Earth. Observations …

Measurement Of Production And Decay Properties Of Bs Mesons Decaying Into J/Psi Phi With The Cms Detector At The Lhc, Giordano Cerizza

Doctoral Dissertations

The production of hadrons containing b-quarks has been measured in proton anti-proton collisions up to center-of-massenergies of 1.96 TeV at the Tevatron. Information at lower energy is provided by electron-positron collision experiments.The underlying theory of hadronic interactions is tuned to those data but cannot reliably predict reaction rates from first principlesfor higher energies. Therefore, it is important to test the extrapolations and optimize model parameters for the new energy regime at the LHC. The b-hadrons from proton-proton collisions are a major source of background in searches for the Higgs boson andother heavy not-yet-discovered particles. Hence, it is important to quantify …