Related papers: Anomalies, Beta Functions and Supersymmetric Unifi…
Recently, conceptually new physics beyond the Standard Model has been proposed by Georgi, where a new physics sector becomes conformal and provides "unparticle" which couples to the Standard Model sector through higher dimensional operators…
Supersymmetric (SUSY) theories are often thought to give large branching ratios for $b \rightarrow s \gamma$ from charged Higgs loops. We show that in many cases chargino loop contributions can cancel those of the Higgs, and SUSY can give…
We construct a supersymmetric flipped SU(5) grand unified model that possesses an $R$ symmetry. This $R$ symmetry forbids dangerous non-renormalizable operators suppressed by a cut-off scale up to sufficiently large mass dimensions so that…
We study the consequences of combining SUSY with a pseudo Nambu-Goldstone boson Higgs coming from an SO(5)/SO(4) coset and partial compositeness. In particular, we focus on how electroweak symmetry breaking and the Higgs mass are reproduced…
We review the theoretical and experimental status of minimal grand unified theories (GUTS), contrasting the failure of minimal non-supersymmetric $SU(5)$ with the success of the minimal supersymmetric $SU(5)$ and minimal supersymmetric…
Models with gauge-Higgs unification on a flat space are typically affected by common problems, the main of which are the prediction of a too small top and Higgs mass and a too low compactification scale. We show how, by breaking the SO(4,1)…
Requiring that supersymmetric SU(5) and SU(6) grand unifications in the heterotic string theory must have 3 chiral families, adjoint (or higher representation) Higgs fields in the grand unifiedgauge group, and a non-abelian hidden sector,…
Non-Abelian gauge theories may have continuum limits in more than four dimensions, supported by non-trivial ultra-violet fixed points. Moreover, such theories can be expected to be accessible to Wilson's epsilon expansion. We investigate…
In the standard model in universal extra dimensions (UED) the mass of the Higgs field is driven to the cutoff of the higher-dimensional theory. This re-introduces a small hierarchy since the compactification scale 1/R should not be smaller…
We consider the doublet-triplet splitting problem in supersymmetric SU(5) grand unified theory in five dimensions where the fifth dimension is non-compact. We point out that an unnatural fine-tuning of parameters in order to obtain the…
In this letter we consider the distinctive phenomenology of supersymmetric models in which the scale of SUSY breaking is very low, \sqrt{F}= O(TeV), focusing on the Higgs sector and the process of electroweak breaking. Using an effective…
We examine a scenario where the Higgs is part of an approximate conformal field theory, and has a scaling dimension greater than one. Such an unparticle Higgs (or Unhiggs) can still break electroweak symmetry and unitarize WW scattering,…
A grand unified model based on SU(5) and supersymmetry is presented. Pairs of superfields belonging to 15 and 15* representations are newly introduced, while gauge coupling unification is satisfied. Improper mass relations in the minimal…
We study models of supersymmetric grand unification based on the SO(10) gauge group. We investigate scenarios of non-universal gaugino masses including models containing a mixture of two representations of hidden sector chiral superfields.…
We consider composite Higgs models where the Higgs is a pseudo-Nambu Goldstone boson arising from the spontaneous breaking of an approximate global symmetry by some underlying strong dynamics. We focus on the SO(5) -> SO(4) symmetry…
We argue for the existence of additional constraints on SU(2) gauge theories in four dimensions when realized in ultraviolet completions admitting an analog of D-brane nucleation. In type II string compactifications these constraints are…
Supersymmetric models with a strongly interacting superconformal hidden sector (HS) may drive soft SUSY breaking scalar masses, bilinear soft term B\mu and Higgs combinations m_{H_{u,d}}^2+\mu^2 to small values at some intermediate scale,…
A natural model of realizing the effective supersymmetry is presented. Two sets of the Standard Model-like gauge group $G_1\times G_2$ are introduced, where $G_i=SU(3)_i\times SU(2)_i\times U(1)_i$, which break diagonally to the Standard…
A familiar anomaly affects SU(2) gauge theory in four dimensions: a theory with an odd number of fermion multiplets in the spin 1/2 representation of the gauge group, and more generally in representations of spin 2r+1/2, is inconsistent. We…
We study the little hierarchy between mass parameters in the Higgs sector and other SUSY breaking masses. This type of spectrum can relieve the fine-tuning problem in the MSSM Higgs sector. Our scenario can be realized by superconformal…