Related papers: Heterotic Orbifold Models
The discovery of Standard-Model like Higgs at 125 GeV may raise more questions than the answers it provides. In particular, the hierarchy problem remains unsolved, and the Standard Model Higgs quartic self-coupling becomes negative below…
An analysis of a special class of type II string theory compactifications is presented. We focus on recent work in one particular orientifold background of intersecting brane models and the resulting four dimensional gauge group and matter…
Twin Higgs models are the prime illustration of neutral naturalness, where the new particles of the twin sector, gauge singlets of the Standard Model (SM), ameliorate the little hierarchy problem. In this work, we analyse phenomenological…
We show that in heterotic string theory -- and dual corners of the landscape including Type I string theory -- the QCD axion mass is bounded from below by $m_a \gtrsim 0.5$ neV, a direct consequence of the model-independent axion whose…
Starting from the Nambu-Goto bosonic string, a four dimensional superstring model is constructed using the equivalence of one boson to two Majorana-Weyl fermions. The conditions of anomaly cancellation in a 'heterotic' string theory lead to…
General features of the spectra of matter states in all 175 models found in a previous work by the author are discussed. Only twenty patterns of representations are found to occur. Accomodation of the Minimal Supersymmetric Standard Model…
We analyze a gauge-Higgs unification model which is based on a gauge theory defined on a six-dimensional spacetime with an $S^2$ extra-space. We impose a symmetry condition for a gauge field and non-trivial boundary conditions of the $S^2$.…
Motivated by orbifold grand unified theories, we construct a class of three-family Pati-Salam models in a Z6 abelian symmetric orbifold with two discrete Wilson lines. These models have marked differences from previously-constructed…
A geometric approach to the standard model in terms of the Clifford algebra $% C\ell_{7}$ is advanced. The gauge symmetries and charge assignments of the fundamental fermions are seen to arise from a simple geometric model involving extra…
We modify a recently proposed heterotic model hep-th/0703210, giving three net-generations of standard model fermions, to get rid of an additional U(1) factor in the gauge group. The method employs a stable SU(5) bundle on a Calabi-Yau…
The goal of identifying the Standard Model of particle physics and its extensions within string theory has been one of the principal driving forces in string phenomenology. Recently, the incorporation of artificial intelligence in string…
We describe the construction of string theory models with semirealistic spectrum in a sector of (anti) D3-branes located at an orbifold singularity at the bottom of a highly warped throat geometry, which is a generalisation of the…
I briefly describe the recent construction of the first specific string D-brane models yielding just the SM massless fermion spectrum. One of the most remarkable facts predicted by these constructions is that the global symmetries of the SM…
We perform model searches on smooth Calabi-Yau compactifications for both the supersymmetric E8xE8 and SO(32) as well as for the non-supersymmetric SO(16)xSO(16) heterotic strings simultaneously. We consider line bundle backgrounds on both…
Nonstandard parafermions are built and their central charges and dimensions are calculated. We then construct new N=2 superconformal field theories by tensoring the parafermions with a free boson. We study the spectrum and modular…
We discuss a model in which the Standard Model (SM) Higgs sector has been extended by additional real and complex triplets. The $\rho\approx 1$ constraint is satisfied by restricting the potential to have an enlarged $\hisym $ global…
Using the current precision electroweak data, we look for the minimal particle content which is necessary to add to the standard model in order to have a complete unification of gauge couplings and gravity at the weakly coupled heterotic…
Moduli stabilisation is key to obtaining phenomenologically viable string models. Non-geometric compactifications, like T-duality orbifolds (T-folds), are capable of freezing many moduli. However, in this Letter we emphasise that T-folds,…
The idea of unification attempts to explain the structure of the Standard Model (SM) in terms of fewer fundamental forces and/or matter fields. However, traditional grand unified theories based on $SU(5)$ and $\mathrm{Spin}(10)$ shed no…
We examine how to construct explicit heterotic string models dual to F-theory in eight dimensions. In doing so we learn about where the moduli spaces of the two theories overlap, and how non-perturbative features leave traces on a purely…