There are several hints that the strong and electroweak forces unify at some very large energy typically assumed to be at around 10 GeV. The quantum fields of the standard model fit nicely into simple representations of a grand unified theory [1] such as e.g. SUð5Þ or SOð10Þ. The idea of unification is extremely attractive for several reasons. For example, a grand unification drastically reduce...

We give a classification of 3-family SO(10) and E6 grand unification in string theory within the framework of conformal field theory and asymmetric orbifolds. We argue that the construction of such models in heterotic string theory requires certain Z6 asymmetric orbifolds that include a Z3 outerautomorphism, the latter yielding a level-3 current algebra for the grand unification gauge group SO(...

We give a classification of 3-family SO(10) and E6 grand unification in string theory within the framework of conformal (free) field theory and asymmetric orbifolds. We argue that the construction of such models in the heterotic string theory requires certain Z6 asymmetric orbifolds that include a Z3 outer-automorphism, the latter yielding a level-3 current algebra for the grand unification gau...

After a brief review of orbifold grand unified theory, we discuss two topics related to the choice of boundary conditions on the orbifold S1/Z2: dynamical rearrangement of gauge symmetry and equivalence classes of boundary conditions.

Abstract A novel invariant gauge field theory realization of Kac-Moody extensions of w∞(w1+∞) algebras and based on a Lie group G is constructed. The most relevant physical feature of this theory is that it describes an effective field theory of ”colored” internal w∞(w1+∞) strings when G = SU(3). We conclude with a discussion of how these theories might provide infinite higher conformal-spins e...

OBJECTIVE To identify examples of how social theories are used in systematic reviews of complex interventions to inform production of Cochrane guidance. STUDY DESIGN AND SETTING Secondary analysis of published/unpublished examples of theories of social phenomena for use in reviews of complex interventions identified through scoping searches, engagement with key authors and methodologists supp...

This document is intended to stimulate debate and discussion in preparation of the Escience Scoping Study Expert Seminar for archaeology and the historic environment. It is a tentative, partial and therefore controversial delineation of the challenges and opportunities which the E-science agenda presents archaeologists and the historic environment sector. It proposes areas of specific activity ...

We consider a supersymmetric hypercolor gauge theory with six flavors of quarks interacting strongly at the grand unification scale. Dynamical breaking of the grand unified SU(5)GUT produces a massless pair of composite color-triplet states. A use of the missing partner mechanism yields eventually a pair of massless Higgs doublets, giving large masses to the color-triplet partners. We prove tha...

In the standard model matter fields form complete representations of a grand unified group whereas Higgs fields belong to incomplete ‘split’ multiplets. This remarkable fact is naturally explained by ‘local grand unification’ in higher-dimensional extensions of the standard model. Here, the generations of matter fields are localized in regions of compact space which are endowed with a GUT gauge...