منابع مشابه
Novel Type I Compactifications
We argue that there are two distinct classes of type I compactification to four dimensions on any space. These two classes are distinguished in a mysterious way by the presence (or absence) of a discrete 6-form potential. In simple examples, duality suggests that the new class of compactifications have reduced numbers of moduli. We also point out analogous discrete choices in M, F and type II c...
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Generalizing the recent work on three-family Type I compactifications, we classify perturbative Type I vacua obtained via compactifying on the T 6/Z2 ⊗ Z2 ⊗ Z3 orbifold with all possible Wilson lines. In particular, we concentrate on models with gauge groups containing the Standard Model gauge group SU(3)c ⊗ SU(2)w ⊗ U(1)Y as a subgroup. All of the vacua we obtain contain D5-branes and are non-...
متن کاملOn Four Dimensional N = 1 Type I Compactifications
We consider four dimensional N = 1 supersymmetric Type I compactifications on toroidal orbifolds T /Γ. In particular, we focus on the Type I vacua which are perturbative from the orientifold viewpoint, that is, on the compactifications with well defined world-sheet expansion. The number of such models is rather constrained. This allows us to study all such vacua. This, in particular, involves c...
متن کاملWallman-type Compactifications
All spaces in this paper are Tychonoff. A Wallman base on a space X is a normal separating ring of closed subsets of X (see Steiner, Duke Math. J. 35 (1968), 269-276). Let T be a compact space and £ a Wallman base on T. For XCZT, define £x = {Ar)X\AE£}. Theorem 1. If X is a dense subspace of T, then T = w£x iff cItAHclrB = 0 whenever A, S£& and AC\B = 0. Theorem 2. T = w£xfor each dense XCZT if...
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It has recently been proposed that certain nonsupersymmetric type II orbifolds have vanishing perturbative contributions to the cosmological constant. We show that techniques of Sen and Vafa allow one to construct dual type II descriptions of these models (some of which have no weakly coupled heterotic dual). The dual type II models are given by the same orbifolds with the string coupling S and...
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ژورنال
عنوان ژورنال: Journal of High Energy Physics
سال: 2002
ISSN: 1029-8479
DOI: 10.1088/1126-6708/2002/01/032