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

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

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

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

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

Strangeness and Hadron Structure

The nucleon wave function may contain a significant component of ssbar pairs, according to several measurements including the pi-nucleon sigma term, charm production and polarization effects in deep-inelastic scattering. In addition, there are excesses of phi production in LEAR and other experiments, above predictions based the naive Okubo-Zweig-Iizuka rule, that may be explained if the nucleon wave function contains a polarized ssbar component. This model also reproduces qualitatively data on Lambda polarization in deep-inelastic neutrino scattering. The strange component of the proton is potentially important for other physics, such as the search for astrophysical dark matter.Comment: 18 pages, 8 eps figures included, talk presented at 16th International Conference On Few-Body Problems In Physics (FB 16), 6-10 Mar 2000, Taipe

From HERA to the LHC

Some personal comments are given on some of the exciting interfaces between the physics of HERA and the LHC. These include the quantitative understanding of perturbative QCD, the possible emergence of saturation phenomena and the Colour-Glass Condensate at small x and large Q^2, the link between forward physics and ultra-high-energy cosmic rays, and new LHC opportunities opened up by the discovery of rapidity-gap events at HERA, including the search for new physics such as Higgs bosons in double-diffraction events.Comment: 14 pages and 9 figures latex using cernrep.cls and mcite.sty, Individual Contribution to the HERA-LHC Worksho