This book is about dark matter’s particle nature and the implications of a new symmetry that appears when a hypothetical dark matter particle is heavy compared to known elementary particles. Dark matter exists and composes about 85% of the matter in the universe, but it cannot be explained in terms of the known elementary particles. Discovering dark matter's particle nature is one of the most pressing open problems in particle physics. This thesis derives the implications of a new symmetry that appears when the hypothetical dark matter particle is heavy compared to the known elementary particles, a situation which is well motivated by the null results of searches at the LHC and elsewhere. The new symmetry predicts a universal interaction between dark matter and ordinary matter, which in turn may be used to determine the event rate and detectable energy in dark matter direct detection experiments. The computation of heavy wino and higgsino dark matter presented in this work has become a benchmark for the field of direct detection. This thesis has also spawned a new field of investigation in dark matter indirect detection, determining heavy WIMP annihilation rates using effective field theory methods. It describes a new formalism for implementing Lorentz invariance constraints in nonrelativistic theories, with a surprising result at 1/M^4 order that contradicts the prevailing ansatz in the past 20 years of heavy quark literature. The author has also derived new perturbative QCD results to provide the definitive analysis of key Standard Model observables such as heavy quark scalar matrix elements of the nucleon. This is an influential thesis, with impacts in dark matter phenomenology, field theory formalism and precision hadronic physics.

This thesis covers several theoretical aspects of WIMP (weakly interacting massive particles) dark matter searches, with a particular emphasis on colliders. It mainly focuses on the use of effective field theories as a tool for Large Hadron Collider (LHC) searches, discussing in detail the issue of their validity, and on simplified dark matter models, which are receiving a growing attention from the physics community. It highlights the theoretical consistency of simplified models, which is essential in order to correctly exploit their potential and for them to be a common reference when comparing results from different experiments. This thesis is of interest to researchers (both theorists and experimentalists) in the field of dark matter searches, and offers a comprehensive introduction to dark matter and to WIMP searches for students and non-experts.

This book is a broad-based text intended to help the growing student body interested in constructing and applying methods of effective field theory to solve problems in their research. It begins with a review of using symmetries to identify the relevant degrees of freedom in a problem, and then presents a variety of methods that can be used to construct various effective theories. A detailed discussion of canonical applications of effective field theory techniques with increasing complexity is given, including Fermi's weak interaction, heavy-quark effective theory, and soft-collinear effective theory. Applications of these techniques to study physics beyond the standard model, dark matter, and quantum and classical gravity are explored. Although most examples come from questions in high-energy physics, many of the methods can also be applied in condensed-matter settings. Appendices include various factoids from group theory and other topics that are used throughout the text, in an attempt to make the book self-contained.

The 'WIMP miracle' for the relic abundance of thermal dark matter motivates weak scale dark matter with renormalizable couplings to standard model particles. This work examines minimal models with such couplings that explain dark matter as a thermal relic. The models contain a singlet dark matter particle with cubic renormalizable couplings between standard model particles and `partner' particles with the same gauge quantum numbers as the standard model particle. The dark matter has spin 0, 1/2, or 1, and may or may not be its own antiparticle. Each model has 3 parameters: the masses of the dark matter and standard model partners, and the cubic coupling. Requiring the correct relic abundance gives a 2-dimensional parameter space where collider and direct detection constraints can be directly compared. This work focuses on the case of dark matter interactions with quarks and leptons.For quark models, collider and direct detection searches are remarkably complementary. Direct detection limits for the cases where the dark matter is not its own antiparticle require dark matter masses to be in the multi-TeV range, where they are extremely difficult to probe in collider experiments. The models where dark matter is its own antiparticle are strongly constrained by collider searches for monojet and jets +MET signals. These models are constrained by direct detection mainly near the limit where the dark matter and partner masses are nearly degenerate, where collider searches become more difficult.In the lepton case, the most sensitive collider probe is the search for leptons + MET, while the most sensitive direct detection channel is scattering off nuclei arising from loop diagrams. Here too collider and direct detection searches are highly complementary: colliders give the only meaningful constraint when dark matter is its own antiparticle, while direct detection is generally more sensitive if the dark matter is not its own antiparticle.

If you do not understand how communication works, then you may become perplexed and frustrated by interactions in the workplace. However, if you understand how communication works, then you have a good chance of diagnosing and fixing communication problems. Best of all, you can influence and motivate your employees, make better decisions, negotiate more effectively, build better work teams, and accomplish business objectives. This book discusses the various forms of communication.

The most popular class of dark matter candidates is the class of weakly-interacting massive particles (WIMPs). The Fermi Large Area Telescope has the possibility of indirectly detecting WIMPs by the flux from their annihilation/decay products. When a WIMP annihilates or decays directly into a photon gamma and another particle Y the photons are monochromatic. Detection of the resulting spectral line(s) would provide convincing evidence for particulate dark matter and could provide the WIMP mass. In the case of no detection, knowledge of the dark matter distribution can be used to place limits on the annihilation cross section and lifetime for the WIMP(s) to Y-gamma channel. We present the spectrum from 4.8 to 264 GeV and spectral line flux upper limits, obtained from a subset of this spectrum, from 7 to 200 GeV. The spatial region of the dataset covers a large portion of the sky, the high latitudes plus the Galactic Center. We report upper limits on the WIMP cross sections for annihilation to gamma-gamma and Z-gamma and lower limits on the WIMP lifetime for decay to gamma-neutrino. We discuss the implications of the spectrum and line flux limits for several dark matter models with optimistic branching ratios for photon channels.