Related papers: Embedded Defects
We examine the soft supersymmetry breaking parameters that result from various ways of embedding the Standard Model (SM) on D-branes within the Type I string picture, allowing the gaugino masses and $\mu$ to have large CP- violating phases.…
We discuss extensions of the Standard Model through extending the electroweak gauge symmetry. An extended electroweak symmetry requires a list of extra fermionic and scalar states. The former is necessary to maintain cancellation of gauge…
In a recent paper, Chivukula and Golden claimed that the electroweak symmetry--breaking sector could be hidden if there were many inelastic channels in the longitudinal $WW$ scattering process. They presented a model in which the $W$'s…
Potentially realistic string models often contain additional abelian gauge factors besides the standard model group. The consequences of such extended gauge structure are manifold both for theory and phenomenology as I show focussing in the…
We investigate the region of restored electroweak symmetry around a superconducting cosmic string coupled to the Weinberg-Salam model with an extra Higgs doublet. We show that the presence of the extra Higgs fields, and in particular their…
We explicitly analyse $O(\alpha')$ corrections to heterotic supergravity on toroidal orbifolds and their resolutions, which play important roles in string phenomenology as well as moduli stabilisation. Using a conformal factor ansatz that…
The standard electroweak model with Dirac neutrinos is extended by way of the principles of electroweak quark-lepton symmetry and weak topological-charge confinement to account for quark-lepton charge relations which, if not accidental, are…
We consider the 1-loop effective potential in type I string theory compactified on a torus, with supersymmetry broken by the Scherk-Schwarz mechanism. At fixed supersymmetry breaking scale M, and up to exponentially suppressed terms, we…
We point out a novel possible mechanism by which the electroweak hierarchy problem can be avoided in the (effective) quantum field theory. Assuming the existence of a UV complete underlying fundamental theory and treating the cutoff scale…
The main features of the recently found classically stable quasi-topological membranes and strings in generic, topologically trivial and weakly coupled two-Higgs extensions of the standard model are briefly reviewed. A variety of localized…
This thesis is almost entirely devoted to studying string theory backgrounds characterized by simple geometrical and integrability properties. The archetype of this type of system is given by Wess-Zumino-Witten models, describing string…
We analyse descriptions of electroweak symmetry breaking in terms of ultralocal antisymmetric tensor fields and gauge-singlet geometric variables, respectively; in particular, the Weinberg--Salam model and, ultimately, dynamical electroweak…
The non-linear sigma model of the dimensionally reduced Einstein (-Maxwell) theory is diagonally embedded into that of the two-dimensional heterotic string theory. Consequently, the embedded string backgrounds satisfy the (electro-magnetic)…
We review the main results of our investigations motivated by the tadpole potentials of ten-dimensional strings with broken supersymmetry. While these are at best partial indications, it is hard to resist the feeling that they do capture…
String theory dynamics on certain fivebrane supertube backgrounds is described by an exactly solvable null-gauged WZW model. We use this description to compute the spectrum of closed string excitations on the three-charge non-supersymmetric…
We consider the minimal U(1)' extension of the standard model (SM) with the classically conformal invariance, where an anomaly-free U(1)' gauge symmetry is introduced along with three generations of right-handed neutrinos and a U(1)' Higgs…
Metastable cosmic strings provide a minimal and predictive origin for the stochastic gravitational-wave background reported by Pulsar Timing Array experiments. We analyse this possibility in electroweak-like dark sectors with a single-stage…
We demonstrate new applications of the trace embedding lemma to the study of piecewise-linear surfaces and the detection of exotic phenomena in dimension four. We provide infinitely many pairs of homeomorphic 4-manifolds $W$ and $W'$…
We derive constraints on the Randall-Sundrum scenario with the standard model fields in the bulk. These result from tree level effects associated with the deformation of the zero mode wave-functions of the W and the Z once electroweak…
An electroweak model is formulated in a finite, four-dimensional quantum field theory without a Higgs particle. The W and Z masses are induced from the electroweak symmetry breaking of one-loop vacuum polarization graphs. The theory…