Related papers: Yet another lesson on the stability conditions in …
We prove the existence of spontaneous symmetry breaking in suitably low-energy eigenstates of certain gapless and frustrated many-body quantum systems, namely symmetric quantum perturbations to classical models which exhibit spontaneous…
We present a novel realization of a composite Higgs, which can naturally produce top partners above the current LHC bounds without increasing the tuning above 10%. The essential ingredients are softened breaking of the Higgs shift symmetry…
Supersymmetric non--linear $\gs$--models in four dimensions with a $D$--term potentials can sometimes have singular kinetic metric terms. As the kinetic terms of scalar fields and their chiral fermionic partners are determine by this…
In this thesis, we investigate the implications of the LHC Higgs data on different BSM scenarios. Since the data seem to agree with the SM expectations, any nonstandard couplings will be strongly constrained. First we investigate, in a…
A new solution to the requirement of two-loop finiteness of the soft supersymmetry breaking terms (SSB) parameters is found in Finite-Gauge-Yukawa unified theories. The new solution has the form of a sum rule for the relevant scalar masses,…
In supersymmetric theories with a strong conformal sector, soft supersymmetry breaking at the TeV scale naturally gives rise to confinement and chiral symmetry breaking at the same scale. We investigate models where such a sector…
We investigate the possibility that supersymmetry is not a fundamental symmetry of nature, but emerges as an accidental approximate global symmetry at low energies. This can occur if the visible sector is non-supersymmetric at high scales,…
For the general two-Higgs doublet model with Yukawa sector of type II (type II 2HDM), the Higgs alignment limit conditions are obtained for the neutral Higgs bosons with indefinite CP-parity $h_1, h_2$ or $h_3$, based on the symbolic…
Boundary conditions on an extra-dimensional interval can be chosen to break bulk gauge symmetries and to reduce the rank of the gauge group. We consider this mechanism in models with gauge trinification. We determine the boundary conditions…
Composite Higgs models provide an attractive solution to the hierarchy problem. However, many realistic models suffer from tuning problems in the Higgs potential. There are often large contributions from the UV dynamics of the composite…
The plethora of scalar fields participating in the formulation of a softly broken supersymmetric theory can threat the stability of the standard vacuum. The generic situation is twofold. Directions in scalar field space may exist along…
In theories of phyiscs beyond the Standard Model (SM), visible sector fields often carry quantum numbers under additional gauge symmetries. One could then imagine a scenario in which these extra gauge symmetries play a role in transmitting…
We study spontaneous supersymmetry breaking in inhomogeneous extensions of ${\cal N}=1$ supersymmetric field theory models in 4-dimensions. The ${\cal N}=1$ Abelian Higgs model with the inhomogeneous mass parameter and the FI coefficient…
Any extension of the standard model that aims to describe TeV-scale physics without fine-tuning must have a radiatively-stable Higgs potential. In little Higgs theories, radiative stability is achieved through so-called collective symmetry…
In this paper we present a model for the spontaneous breaking of parity with two Higgs doublets and two neutral Higgs singlets which are even and odd under D-parity. The condition $ v_R >>v_L $ can be satisfied without introducing…
In the framework of a recently proposed topological approach to phase transitions, some sufficient conditions ensuring the presence of the spontaneous breaking of a Z_2 symmetry and of a symmetry-breaking phase transition are introduced and…
All global symmetries are expected to be explicitly broken by quantum gravitational effects, and yet may play an important role in Particle Physics and Cosmology. As such, any evidence for a well-preserved global symmetry would give insight…
Combining precision measurements and the Higgs boson search limit, the electroweak data has evolved to a point where new physics is favored whether the 3.2 sigma A_{FB}^b anomaly is genuine or not. Such new physics could greatly alter the…
We introduce a new class of Composite Higgs models in which electroweak symmetry is broken by a seesaw-like mechanism. If a global symmetry is broken sequentially at different scales, two sets of pseudo-Goldstone bosons will arise, one set…
These notes are an introduction to asymptotic symmetries in gauge theories, with a focus on general relativity in four dimensions. We explain how to impose consistent sets of boundary conditions in the gauge fixing approach and how to…