This thesis presents a search for long-lived particles decaying into displaced electrons and/or muons with large impact parameters. This signature provides unique sensitivity to the production of theoretical lepton-partners, sleptons. These particles are a feature of supersymmetric theories, which seek to address unanswered questions in nature. The signature searched for in this thesis is difficult to identify, and in fact, this is the first time it has been probed at the Large Hadron Collider (LHC). It covers a long-standing gap in coverage of possible new physics signatures. This thesis describes the special reconstruction and identification algorithms used to select leptons with large impact parameters and the details of the background estimation. The results are consistent with background, so limits on slepton masses and lifetimes in this model are calculated at 95% CL, drastically improving on the previous best limits from the Large Electron Positron Collider (LEP).

This book summarizes the science to be carried out by the upcoming Cherenkov Telescope Array, a major ground-based gamma-ray observatory that will be constructed over the next six to eight years. The major scientific themes, as well as core program of key science projects, have been developed by the CTA Consortium, a collaboration of scientists from many institutions worldwide.CTA will be the major facility in high-energy and very high-energy photon astronomy over the next decade and beyond. CTA will have capabilities well beyond past and present observatories. Thus, CTA's science program is expected to be rich and broad and will complement other major multiwavelength and multimessenger facilities. This book is intended to be the primary resource for the science case for CTA and it thus will be of great interest to the broader physics and astronomy communities. The electronic version (e-book) is available in open access.

Supersymmetry is at an exciting stage of development. It extends the Standard Model of particle physics into a more powerful theory that both explains more and allows more questions to be addressed. Most important, it opens a window for studying and testing fundamental theories at the Planck scale. Experimentally we are finally entering the intensity and energy regions where superpartners are likely to be detected, and then studied. There has been progress in understanding the remarkable physics implications of supersymmetry, including the derivation of the Higgs mechanism, the unification of the Standard Model forces, cosmological connections such as a candidate for the cold dark matter of the universe and the scalar fields that drive inflation and their potential, the relationship to Planck scale theories, and more.While there are a number of reviews and books where the mathematical structure and uses of supersymmetry can be learned, there are few where the particle physics is the main focus. This book fills that gap. It begins with an excellent pedagogical introduction to the physics and methods and formalism of supersymmetry, by S Martin, which is accessible to anyone with a basic knowledge of the Standard Model of particle physics. Next is an overview of open questions by K Dienes and C Kolda, followed by chapters on topics ranging from how to detect superpartners to connections with Planck scale theories, by leading experts.This invaluable book will allow any interested physicist to understand the coming experimental and theoretical progress in supersymmetry, and will also help students and workers to quickly learn new aspects of supersymmetry they want to pursue.