18,859 research outputs found
M theory, Joyce Orbifolds and Super Yang-Mills
We geometrically engineer d=4 N=1 supersymmetric Yang-Mills theories by
considering M theory on various Joyce orbifolds. We argue that the
superpotential of these models is generated by fractional membrane instantons.
The relation of this superpotential to membrane anomalies is also discussed.Comment: v2: A careless error which appeared at the end of section four and
propagated to section six has been corrected. (The mistake was to identify
the Coxeter number of the gauge group with the order of a certain finite
group). The results are unchanged. Some references have also been added. v3:
A previously unrecognised monodromy recognised. New monodromy free examples
added. 21 pages, Late
N=1 Heterotic/M-theory Duality and Joyce Manifolds
We present an ansatz which enables us to construct heterotic/M-theory dual
pairs in four dimensions. It is checked that this ansatz reproduces previous
results and that the massless spectra of the proposed dual pairs agree. The new
dual pairs consist of M-theory compactifications on Joyce manifolds of
holonomy and Calabi-Yau compactifications of heterotic strings. These results
are further evidence that M-theory is consistent on orbifolds. Finally, we
interpret these results in terms of M-theory geometries which are K3 fibrations
and heterotic geometries which are conjectured to be fibrations. Even
though the new dual pairs are constructed as non-freely acting orbifolds of
existing dual pairs, the adiabatic argument is apparently not violated.Comment: 25 pages, Late
Planes, branes and automorphisms: I. Static branes
This is the first of a series of papers devoted to the group-theoretical
analysis of the conditions which must be satisfied for a configuration of
intersecting M5-branes to be supersymmetric. In this paper we treat the case of
static branes. We start by associating (a maximal torus of) a different
subgroup of Spin(10) with each of the equivalence classes of supersymmetric
configurations of two M5-branes at angles found by Ohta & Townsend. We then
consider configurations of more than two intersecting branes. Such a
configuration will be supersymmetric if and only if the branes are G-related,
where G is a subgroup of Spin(10) contained in the isotropy of a spinor. For
each such group we determine (a lower bound for) the fraction of the
supersymmetry which is preserved. We give examples of configurations consisting
of an arbitrary number of non-coincident intersecting fivebranes with
fractions: 1/32, 1/16, 3/32, 1/8, 5/32, 3/16 and 1/4, and we determine the
resulting (calibrated) geometry.Comment: 26 pages (Added a reference and modified one table slightly.
- …