169 research outputs found
Standard Model bundles of the heterotic string
We show how to construct supersymmetric three-generation models with gauge
group and matter content of the Standard Model in the framework of
non-simply-connected elliptically fibered Calabi-Yau manifolds Z. The elliptic
fibration on a cover Calabi-Yau, where the model has 6 generations of SU(5) and
the bundle is given via the spectral cover description, has a second section
leading to the needed free involution. The relevant involution on the defining
spectral data of the bundle is identified for a general Calabi-Yau of this type
and invariant bundles are generally constructible.Comment: 23 pp; minor remarks adde
The Background Field Method for N = 2 Super Yang-Mills Theories in Harmonic Superspace
The background field method for N=2 super Yang-Mills theories in harmonic
superspace is developed. The ghost structure of the theory is investigated. It
is shown that the ghosts include two fermionic real omega-hypermultiplets
(Faddeev-Popov ghosts) and one bosonic real omega-hypermultiplet
(Nielsen-Kallosh ghost), all in the adjoint representation of the gauge group.
The one-loop effective action is analysed in detail and it is found that its
structure is determined only by the ghost corrections in the pure super
Yang-Mills theory. As applied to the case of N=4 super Yang-Mills theory,
realized in terms of N=2 superfields, the latter result leads to the remarkable
conclusion that the one-loop effective action of the theory does not contain
quantum corrections depending on the N=2 gauge superfield only. We show that
the leading low-energy contribution to the one-loop effective action in the N=2
SU(2) super Yang-Mills theory coincides with Seiberg's perturbative holomorphic
effective action.Comment: 17 pages, Late
An M-Theory Perspective on Heterotic K3 Orbifold Compactifications
We analyze the structure of heterotic M-theory on K3 orbifolds by presenting
a comprehensive sequence of M-theoretic models constructed on the basis of
local anomaly cancellation. This is facilitated by extending the technology
developed in our previous papers to allow one to determine "twisted" sector
states in non-prime orbifolds. These methods should naturally generalize to
four-dimensional models, which are of potential phenomenological interest.Comment: 58 pages, LaTe
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