Introduction to the Terascale

We briefly review the status of the electroweak theory, in the Standard Model and beyond, on the brink of the LHC start.Comment: Lecture given at the SLAC Summer Institute, July 200

Obscuration-dependent evolution of Active Galactic Nuclei

We aim to constrain the evolution of AGN as a function of obscuration using an X-ray selected sample of $\sim2000$ AGN from a multi-tiered survey including the CDFS, AEGIS-XD, COSMOS and XMM-XXL fields. The spectra of individual X-ray sources are analysed using a Bayesian methodology with a physically realistic model to infer the posterior distribution of the hydrogen column density and intrinsic X-ray luminosity. We develop a novel non-parametric method which allows us to robustly infer the distribution of the AGN population in X-ray luminosity, redshift and obscuring column density, relying only on minimal smoothness assumptions. Our analysis properly incorporates uncertainties from low count spectra, photometric redshift measurements, association incompleteness and the limited sample size. We find that obscured AGN with $N_{H}>{\rm 10^{22}\, cm^{-2}}$ account for ${77}^{+4}_{-5}\%$ of the number density and luminosity density of the accretion SMBH population with $L_{{\rm X}}>10^{43}\text{ erg/s}$, averaged over cosmic time. Compton-thick AGN account for approximately half the number and luminosity density of the obscured population, and ${38}^{+8}_{-7}\%$ of the total. We also find evidence that the evolution is obscuration-dependent, with the strongest evolution around $N_{H}\thickapprox10^{23}\text{ cm}^{-2}$. We highlight this by measuring the obscured fraction in Compton-thin AGN, which increases towards $z\sim3$, where it is $25\%$ higher than the local value. In contrast the fraction of Compton-thick AGN is consistent with being constant at $\approx35\%$, independent of redshift and accretion luminosity. We discuss our findings in the context of existing models and conclude that the observed evolution is to first order a side-effect of anti-hierarchical growth.Comment: Published in Ap

New Physics and the LHC

In these lectures I start by briefly reviewing the status of the electroweak theory, in the Standard Model and beyond. I then discuss the motivation and the possible avenues for new physics, on the brink of the LHC start.Comment: 35 pages, 8 figures. Lectures given at the Lake Louise Winter Institute, Lake Louise, Alberta, Canada, 18-23 February 200

Les Houches 2011: Physics at TeV Colliders New Physics Working Group Report

We present the activities of the "New Physics" working group for the "Physics at TeV Colliders" workshop (Les Houches, France, 30 May-17 June, 2011). Our report includes new agreements on formats for interfaces between computational tools, new tool developments, important signatures for searches at the LHC, recommendations for presentation of LHC search results, as well as additional phenomenological studies.Comment: 243 pages, report of the Les Houches 2011 New Physics Group; fix three figure

The landscape of QCD axion models

We review the landscape of QCD axion models. Theoretical constructions that extend the window for the axion mass and couplings beyond conventional regions are highlighted and classified. Bounds from cosmology, astrophysics and experimental searches are reexamined and updated.Comment: Review article for Physics Reports, 151 pages. Few typos and signs corrected. Matches journal versio

New Physics Ideas from Strongly Coupled Theories

The work in this thesis attempts to account for New Physics (NP) to extend the Standard Model (SM) in two complementary ways. The main aim is to address the problem of dark sectors/dark matter in the SM. The first part of the thesis extends the SM with a putative new sector which is SM-neutral and light with mass similar to the MeV scale. This dark sector can give phenomenological signatures in future neutrino oscillation experiments. The second part of the thesis involves extending both the SM matter and SM gauge group with a new strong force called dark colour. Vector-like dark fermions charged under dark colour are added which can give a composite baryon - a dark matter candidate with mass close to 100 TeV. Such theories can have an ultraviolet completion in unified SU(5) theories, we find that this requirement can strongly constrain such composite DM theories as well as give novel predictions for DM cosmology

Weak Scale Supersymmetry

Supersymmetric models of particle physics predict new superpartner matter states for each particle in the Standard Model. These superpartners will have wide ranging implications, from cosmology to observations at high energy accelerators, such as CERN's LHC. In this 2006 text, the authors develop the basic concepts of supersymmetry and show how it can be incorporated into a theoretical framework for describing unified theories of elementary particles. They develop the technical tools of supersymmetry using four-component spinor notation familiar to high energy experimentalists and phenomenologists. The text takes the reader from an abstract formalism to a straightforward recipe for writing supersymmetric gauge theories of particle physics, and ultimately to the calculations necessary for practical applications at colliders and in cosmology. This is a comprehensive, practical and accessible introduction to supersymmetry for experimental and phenomenological particle physicists and graduate students. It has been reissued as an Open Access publication

Methods for High Resolution Study of the Geometry of Active Galactic Nuclei with Applications of Reverberation Mapping and Optical Interferometry

All but a few Active Galactic Nuclei are too distant for any single aperture telescope to resolve, yet the geometry of these objects is key to our understanding of the evolution of galaxies in the universe. To study the geometry of Active Galactic Nuclei, methods are leveraged using smaller telescopes to gain resolution rather than relying on larger and larger single aperture telescopes. Principally, these are via reverberation mapping which utilizes temporal and spectral resolution to gain spatial resolution and interferometry which sacrifices the light gathering power of large aperture telescopes for high angular resolution. To provide a tool for recovering geometric indicators of AGNs from reverberation mapping data, an image reconstructing algorithm is developed utilizing the alternating direction method of multipliers with compressed sensing regularization. This new algorithm is applied to the Arp 151 dataset from the Lick AGN Monitoring Project 2008. In addition to the reverberation mapping algorithm, the first calibrated extragalactic results for the CHARA Array are presented for NGC 4151. At the extreme detection limit for the instruments of the CHARA Array, the observational strategies utilized for successful observations and the results obtained are discussed