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We introduce a set of CMSSM benchmark scenarios that take into account the constraints from LEP, Tevatron, $b to s gamma$, $g_mu - 2$ and cosmology. The benchmark points are chosen to span the range of different generic possibilities, including focus-point models, points where coannihilation effects on the relic density are important, and points with rapid relic annihilation via direct-channel Higgs poles, as well as points with smaller sparticle masses. We make initial estimates of the physics reaches of different accelerators, including the LHC, and $e^+ e^-$ colliders in the sub- and multi-TeV ranges. We stress the complementarity of hadron and lepton colliders, with the latter favoured for non-strongly-interacting particles and precision measurements.
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The recent discovery of a Higgs boson by the LHC experiments has profound implications for supersymmetric models. In particular, in the context of restricted models, such as the supergravity-inspired constrained minimal supersymmetric standard model, one finds that preferred regions in parameter space have large soft supersymmetry-breaking trilinear couplings. This potentially gives rise to charge- and/or color-breaking minima besides those with the correct breaking of $SU(2)_L times U(1)_Y$. We investigate the stability of parameter points in this model against tunneling to possible deeper color- and/or charge-breaking minima of the one-loop effective potential. We find that allowed regions of the parameter space with light staus or with light stops are seriously constrained by the requirement that the tunneling time out of the normal electroweak-symmetry-breaking vacuum is more than a fifth of the age of the known Universe. We also find that thumb rule conditions on Lagrangian parameters based on specific directions in the tree-level potential are of limited use.
{it Why continue looking for supersymmetry?} Over and above the aesthetic and theoretical motivations from string theory, there are several longstanding phenomenological motivations for TeV-scale supersymmetry such as the electroweak scale, and the lightest supersymmetric particle (LSP) as cold dark matter. Run~1 of the LHC has actually provided three extra motivations, namely the stabilization of the electroweak vacuum, and successful predictions for the Higgs mass and couplings. {it How to look for it?} There are several examples of emergent supersymmetry, the most recent being on the surfaces of topological insulators, and some sort of effective supersymmetry could be useful for boosting the power of laser arrays. At the LHC, attention is moving towards signatures that had previously been neglected, such as long-lived charged particles - which might be an opportunity for the MoEDAL experiment.
If new physics is found at the LHC (and the ILC) the reconstruction of the underlying theory should not be biased by assumptions about high--scale models. For the mapping of many measurements onto high--dimensional parameter spaces we introduce SFitter with its new weighted Markov chain technique. SFitter constructs an exclusive likelihood map, determines the best--fitting parameter point and produces a ranked list of the most likely parameter points. Using the example of the TeV--scale supersymmetric Lagrangian we show how a high--dimensional likelihood map will generally include degeneracies and strong correlations. SFitter allows us to study such model--parameter spaces employing Bayesian as well as frequentist constructions. We illustrate in detail how it should be possible to analyze high--dimensional new--physics parameter spaces like the TeV--scale MSSM at the LHC. A combination of LHC and ILC measurements might well be able to completely cover highly complex TeV--scale parameter spaces.
Effective Field Theories (EFTs) capture effects from heavy dynamics at low energy and represent an essential ingredient in the context of Standard Model (SM) precision tests. This document gathers a number of relevant scenarios for heavy physics beyond the SM and presents explicit expressions for the Wilson coefficients in their low-energy EFT. It includes i) weakly coupled scenarios in which one or a few particles of different spins and quantum numbers interact linearly with the SM and generate EFT effects at tree-level, ii) scenarios where heavy particles interact quadratically whereupon the resulting EFT arises only at loop-level and iii) strongly coupled scenarios where the size of Wilson coefficients is controlled by symmetry arguments. This review aims at motivating experimental EFT studies in which only a subset of all possible EFT interactions is used, as well as facilitating the theoretical interpretation of EFT fits.
General relativity (GR) is the current description of gravity in modern physics. One of the cornerstones of GR, as well as Newtons theory of gravity, is the weak equivalence principle (WEP), stating that the trajectory of a freely falling test body is independent of its internal structure and composition. WEP is known to be valid for the normal matter with a high precision. However, due to the rarity of antimatter and weakness of the gravitational forces, the WEP has never been confirmed for antimatter. The current direct bounds on the ratio between the gravitational and inertial masses of the antihydrogen do not rule out a repulsive nature for the antimatter gravity. Here we establish an indirect bound of 0.13% on the difference between the gravitational and inertial masses of the positron (antielectron) from the analysis of synchrotron losses at the Large Electron-Positron collider (LEP). This serves as a confirmation of the conventional gravitational properties of antimatter without common assumptions such as, e.g., coupling of gravity to virtual particles, dynamics of distant astrophysical sources and the nature of absolute gravitational potentials.
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