[en] The following topics are dealt with: The ascertainment of scientific virgin territory by means of the LHC ar CERN, the study of actual questions of cosmology and astrophysics like dark matter and dark energy by means of the LHC, the presently existing anomalies in the data with regards to new phenomena together with statistical methods for the correct estimation of such observations, the supplement of other experiments for the LHC experiments, the Higgs boson, supersymmetry, higher dimensions, the study of quantum gravity in accelerator experiments with regards to the string theory. (HSI)

[en] The following topics are dealt with: The development of the Standard Model on the base of relativity theory, quantum theory, and the detection of new particles, the physics of the Standard Model, the production of new particles with the LHC, the importance of the discovery of a Higgs boson for our picture of the world. (HSI)

[en] The following topics are dealt with: The classical scalar field, canonical quantization, interactions, path integrals for scalar fields, regularization and renormalization, the Dirac field, gauge fields, gauge symmetries and Ward identities, quantum electrodynamics together with their regularization and renormalization, the standard model of particle physics. (HSI)

[en] In this thesis we have investigated phenomenological implications which arise for cosmology and collider physics when the electroweak symmetry breaking sector of warped higgsless models is extended to include warped supersymmetry with conserved R parity. The goal was to find the simplest supersymmetric extension of these models which still has a realistic light spectrum including a viable dark matter candidate. To accomplish this, we have used the same mechanism which is already at work for symmetry breaking in the electroweak sector to break supersymmetry as well, namely symmetry breaking by boundary conditions. While supersymmetry in five dimensions contains four supercharges and is therefore directly related to 4D N=2 supersymmetry, half of them are broken by the background leaving us with ordinary N=1 theory in the massless sector after Kaluza-Klein expansion. We thus use boundary conditions to model the effects of a breaking mechanism for the remaining two supercharges. The simplest viable scenario to investigate is a supersymmetric bulk and IR brane without supersymmetry on the UV brane. Even though parts of the light spectrum are effectively projected out by this mechanism, we retain the rich phenomenology of complete N=2 supermultiplets in the Kaluza-Klein sector. While the light supersymmetric spectrum consists of electroweak gauginos which get their O(100 GeV) masses from IR brane electroweak symmetry breaking, the light gluinos and squarks are projected out on the UV brane. The neutralinos, as mass eigenstates of the neutral bino-wino sector, are automatically the lightest gauginos, making them LSP dark matter candidates with a relic density that can be brought to agreement withWMAP measurements without extensive tuning of parameters. For chargino masses close to the experimental lower bounds at around m_χ⁺∼100.. 110 GeV, the dark matter relic density points to LSP masses of around m_χ∼90 GeV. At the LHC, the standard particle content of our model shares most of the key features of known warped higgsless models. We have performed Monte Carlo simulations of warped higgsless LSP and NLSP production at a benchmark point using O'Mega/WHIZARD, concentrating on /p_T in association with third generation quarks. After background reduction cuts on the quark momenta and angles, we get hadronic cross sections of σ>100 fb at 14 TeV with characteristic /p_T distributions for χχt anti t final states, while the final states with bb pairs have much lower event rates and shapes which are hard to discern in experiments. Our results suggest that the discovery of warped higgsless LSP dark matter at the LHC via missing energy is within reach for the first few fb^-1 at 14 TeV if b and in particular t identification is reliable. (orig.)

[en] I discuss the current theoretical and phenomenological constraints on additional chiral fermions beyond the three Standard Model generations of quarks and leptons. While the conventional fourth generation is virtually ruled out from Higgs searches, direct searches and perturbativity, other fermion representations are still in better shape in this respect. We derive the bounds on Higgs masses and exotic fermion masses from perturbativity and vacuum stability, and relate the different scenarios to current Higgs searches at the LHC.

[en] The framework of E₆ GUTs permits the unification of Matter and Higgs fields in the fundamental representation. If some of the resulting exotics remain light at the Terascale, an alternative to standard MSSM unification must be realized in nature. The talk adresses the challenges involved in the construction of such unification scenarios and superpotentials, and outlines solutions in 4D and on T²/Γ compactifications.

[en] Supersymmetric extensions of warped higgsless models of electroweak symmetry breaking provide a dark matter candidate which naturally has a relic density compatible with recent observations. We find an extended particle spectrum which reflects the close relationship of N=1 SUSY in 5 dimensions with N=2 SUSY in four dimensions. Among the new states in the gauge multiplets are scalars with properties which add interesting aspects to the forthcoming Higgs searches at the LHC

[en] We introduce a minimal supersymmetric extension of a Higgsless model for electroweak symmetry breaking in a warped extra dimension. In contrast to the nonsupersymmetric version, our model naturally contains a candidate for cold dark matter. No Kaluza-Klein parity is required, because its stability is guaranteed by an R-parity. We discuss the regions in parameter space that are compatible with the observed dark matter content of our Universe and are allowed by electroweak precision measurements as well as direct searches.

[en] We investigate single Higgs and Higgs pair production at the LHC in models of Universal Extra Dimensions. After calculating the relevant cross sections, we use the UED model as a testing ground for the Effective Field Theory approach to physics beyond the Standard Model. We show how the UED contributions to Higgs production can be matched to a dimension-6 operator. We then discuss the range of validity of this approach, in particular for Higgs pair production, and determine the sensitivity to the number of KK modes in the loop.

[en] We present a supersymmetric TeV-scale theory with a matter content filling complete E₆ multiplets arising from an orbifold construction with E₆ constituting the gauge group in the bulk of the extra dimensions. The main focus lies on the structures linking the Lagrangian parameters at the orbifold compactification scale to the TeV-scale spectra as well as their algorithmic realization in the automated spectrum generator EXSPECT. Among the most interesting features in this setup are the multi-scale gauge coupling unification scheme, top-bottom Yukawa unification, and its implications on the vacuum structure breaking the electroweak symmetry. In order to find solutions on the high-dimensional space of input parameters incorporating the aforementioned aspects, we use Monte-Carlo Markov-Chain techniques. The first results obtained with this method as well as a phenomenological study of the production of the heavy neutral gauge boson at the LHC for these cases conclude our discussion.