Theoretical Summary: 1999 Electroweak Session of the Rencontres de Moriond

The following aspects of the electroweak interactions are discussed, based on presentations here: the status of the Standard Model, CP violation, neutrino masses and oscillations, supersymmetry and models in extra dimensions, and future projects. Particular emphasis is laid on the tests of CP and CPT by KTeV and CPLEAR, on the problems of degenerate neutrinos, on supersymmetric dark matter, on future long-baseline neutrino beams, and on muon storage rings that may be used as neutrino factories.Comment: 25 LaTeX pages, 5 eps figures, Invited talk presented at the 1999 Electroweak Session of the Rencontres de Morion

Outlook on Neutrino Physics

Some of the hot topics in neutrino physics are discussed, with particular emphasis on neutrino oscillations. After proposing credibility criteria for assessing various claimed effects, particular stress is laid on the solar neutrino deficit, which seems unlikely to have an astrophysical explanation. Comments are also made on the possibility of atmospheric neutrino oscillations and on the LSND experiment, as well as cosmological aspects of neutrinos and neutralinos. Several of the central issues in neutrino physics may be resolved by the new generation of experiments now underway, such as CHORUS, NOMAD and Superkamiokande, and in preparation, such as SNO and a new round of accelerator- and reactor-based neutrino-oscillation experiments. At the end, there is a brief review of ways in which present and future CERN experiments may be able to contribute to answering outstanding questions in neutrino physics.Comment: 27 pages, LaTex, uses sprocl.sty, Invited Talk presented at the conclusion of the Neutrino 96 Conference, Helsinki, June 199

Prospects for Future Collider Physics

One item on the agenda of future colliders is certain to be the Higgs boson. What is it trying to tell us? The primary objective of any future collider must surely be to identify physics beyond the Standard Model, and supersymmetry is one of the most studied options. it Is supersymmetry waiting for us and, if so, can LHC Run 2 find it? The big surprise from the initial 13-TeV LHC data has been the appearance of a possible signal for a new boson X with a mass ~750 GeV. What are the prospects for future colliders if the X(750) exists? One of the most intriguing possibilities in electroweak physics would be the discovery of non-perturbative phenomena. What are the prospects for observing sphalerons at the LHC or a future collider?Comment: 17 pages, 14 figures, contribution to the Hong Kong UST IAS Programme and Conference on High-Energy Physics, based largely on personal research with various collaborator

The Physics Landscape after the Higgs Discovery at the LHC

What is the Higgs boson telling us? What else is there, maybe supersymmetry and/or dark matter? How do we find it? These are now the big questions in collider physics that I discuss in this talk, from a personal point of view.Comment: Invited plenary talk at SILAFAE 2014, Medell\'in, Colombia, 12 pages, 21 figure

Limits of the Standard Model

Supersymmetry is one of the most plausible extensions of the Standard Model, since it is well motivated by the hierarchy problem, supported by measurements of the gauge coupling strengths, consistent with the suggestion from precision electroweak data that the Higgs boson may be relatively light, and provides a ready-made candidate for astrophysical cold dark matter. In the first lecture, constraints on supersymmetric models are reviewed, the problems of fine-tuning the electroweak scale and the dark matter density are discussed, and a number of benchmark scenarios are proposed. Then the prospects for discovering and measuring supersymmetry at the LHC, linear colliders and in non-accelerator experiments are presented. In the second lecture, the evidence for neutrino oscillations is recalled, and the parameter space of the seesaw model is explained. It is shown how these parameters may be explored in a supersymmetric model via the flavour-changing decays and electric dipole moments of charged leptons. It is shown that leptogenesis does not relate the baryon asymmetry of the Universe directly to CP violation in neutrino oscillations. Finally, possible CERN projects beyond the LHC are mentioned.Comment: Lectures given at the PSI Summer School, Zuoz, August 2002, 40 pages, 28 figures, uses axodraw.sty, cernrep.cls (included

Supersymmetry for Alp Hikers

These lectures provide a phenomenological introduction to supersymmetry, concentrating on the minimal supersymmetric extension of the Standard Model (MSSM). In the first lecture, motivations are provided for thinking that supersymmetry might appear at the TeV scale, including the naturalness of the mass hierarchy, gauge unification and the probable mass of the Higgs boson. In the second lecture, simple globally supersymmetric field theories are introduced, with the emphasis on features important for model-building. Supersymmetry breaking and local supersymmetry (supergravity) are introduced in the third lecture, and the structure of sparticle mass matrices and mixing are reviewed. Finally, the available experimental and cosmological constraints on MSSM parameters are discussed and combined in the fourth lecture, and the prospects for discovering supersymmetry in future experiments are previewed.Comment: 45 pages, 19 figures, Lectures at the European School of High-Energy Physics, Beatenberg, Switzerland, 26 Aug - 8 Sept 200

Looking Back at the First Decade of 21st-Century High-Energy Physics

On the occasion of the Tenth Conference on String Phenomenology in 2011, I review the dramatic progress since 2002 in experimental tests of fundamental theoretical ideas. These include the discovery of (probably fermionic) extra dimensions at the LHC, the discovery of dark matter particles, observations of charged-lepton flavour violation, the debut of quantum gravity phenomenology and the emergence of space-time from the string soup.Comment: 18 pages, 16 eps figures, uses ws-procs9x6.cls (included

Higgs Physics

These lectures review the background to Higgs physics, its current status following the discovery of a/the Higgs boson at the LHC, models of Higgs physics beyond the Standard Model and prospects for Higgs studies in future runs of the LHC and at possible future colliders.Comment: 52 pages, 45 figures, Lectures presented at the ESHEP 2013 School of High-Energy Physics, to appear as part of the proceedings in a CERN Yellow Repor

Theory Summary and Prospects

This talk reviews some of the theoretical progress and outstanding issues in QCD, flavour physics, Higgs and electroweak physics and the search for physics beyond the Standard Model at the Tevatron and the LHC, and previews some physics possibilities for future runs of the LHC and proposed future hadron colliders.Comment: 14 pages, 7 figures, Presented at the Second Annual Conference on Large Hadron Collider Physics Columbia University, New York, U.S.A June 2-7, 201

Beyond the Standard Model for Hillwalkers

In the first lecture, the Standard Model is reviewed, with the aim of seeing how its successes constrain possible extensions, the significance of the apparently low Higgs mass indicated by precision electroweak experiments is discussed, and defects of the Standard Model are examined. The second lecture includes a general discussion of the electroweak vacuum and an introduction to supersymmetry, motivated by the gauge hierarchy problem. In the third lecture, the phenomenology of supersymmetric models is discussed in more detail, with emphasis on the information provided by LEP data. The fourth lecture introduces Grand Unified Theories, with emphases on general principles and on neutrino masses and mixing. Finally, the last lecture contains short discussions of some further topics, including supersymmetry breaking, gauge-mediated messenger models, supergravity, strings and $M$ phenomenology.Comment: Lectures presented at 1998 European School of High-Energy Physics, 64 pages LaTeX, 37 eps figures, uses cernrep.cl