A search is presented for the decay of the Standard Model Higgs boson or another scalar boson to a pair of weakly-interacting, long-lived particles in 20.3 fb$^{-1}$ of proton-proton collisions at $\sqrt{s} = 8$ TeV recorded in 2012 by the ATLAS detector. The strategy requires that one of the long-lived particles decay inside ...

The axion is a hypothetical elementary particle resulting from a solution to the “Strong-CP” problem. This serious problem in the standard model of particle physics is manifested as a 10<super>10</super> discrepancy between the measured upper limit and the calculated value of the neutron's electric dipole moment. Furthermore, ...

The searches for a Beyond Standard Model (BSM) heavy CP-odd Higgs boson $A$ decaying to $Zh$ in the context of two-Higgs-doublet models (2HDM), and Minimal Supersymmetric Standard Model (MSSM) neutral Higgs bosons $H/A$ decaying to a tau pair are presented. The search for the heavy CP-odd Higgs boson, $A$, is conducted through ...

Since it was conjectured almost 20 years ago, AdS/CFT duality, or holography, has enabled steady progress in understanding certain gauge theories in the strongly coupled limit. In this thesis we examine various aspects of holography and holographic techniques, as well as particular applications to the dynamics of strongly ...

The neutrino, an elementary particle, has been the subject of experimental investigation for over 50 years. Recent experiments have shown that neutrinos have mass and oscillate, but questions about fundamental properties of the neutrino remain. The observation of neutrinoless double-beta decay could determine whether lepton ...

The first measurement of the inclusive cross-section of the <italic>Z</italic> boson decaying to two tau leptons was measured with the ATLAS detector at the LHC. The data sample in this analysis represents an integrated luminosity of 35 pb<super>-1</super> of proton-proton collisions at a center of mass energy of sqrt(s)=7 ...

In this thesis the development and study of a method for a model-dependent measurement of the muon neutrino charged current (CC) single pion interaction's positive pion momentum spectrum is proposed. The measurement is part of the Tokai-to-Kamioka (T2K) experiment and was performed in Tokai at the near detector hall, using ...

In this thesis the development and study of a method for a model-dependent measurement of the muon neutrino charged current (CC) single pion interaction's positive pion momentum spectrum is proposed. The measurement is part of the Tokai-to-Kamioka (T2K) experiment and was performed in Tokai at the near detector hall, using ...

The theory of quantum chromodynamics (QCD) encodes the strong interactions that bind quarks and gluons into nucleons and that bind nucleons into nuclei. Predictive control of QCD would allow nuclear structure and reactions as well as properties of supernovae and neutron stars to be theoretically studied from first principles. ...

The Tokai-to-Kamiokande (T2K) experiment is an off-axis, long baseline neutrino oscillation experiment based in Japan. One of the largest sources of systematic uncertainty in the oscillation analysis is the uncertainty on neutrino cross sections. In this thesis, we use the π<super>0</super> detector (P0D) of the T2K Near ...