262 research outputs found
Multiple anomalous U(1)s in heterotic blow-ups
The existence of multiple anomalous U(1)s is demonstrated explicitly in a
blow-up version of a heterotic Z_3 orbifold. Another blow-up of the same
orbifold supports further evidence for the type-I/heterotic duality in four
dimensions. It has a single anomalous U(1) which does not factorize
universally. As multiple anomalous U(1)s as well as non-universal factorization
have never been established on heterotic orbifolds explicitely, these findings
might appear contradictory at first sight. Possible inconsistencies are avoided
by reinterpreting a charged twisted state as a second non-universal localized
axion. The mismatch between the charges of the orbifold and blow-up spectra is
resolved by suitable field redefinitions. The anomaly of the field
redefinitions corresponds to the difference of blow-up and heterotic orbifold
anomalies.Comment: 7 pages LaTe
Spontaneous localization of bulk matter fields
We study models compactified on S^1/Z_2 with bulk and brane matter fields
charged under U(1) gauge symmetry. We calculate the FI-terms and show by
minimizing the resulting potential that supersymmetry or gauge symmetry is
spontaneously broken if the sum of the charges does not vanish. Even if this
sum vanishes, there could be an instability as a consequence of localized
FI-terms. This leads to a spontaneous localization of charged bulk fields on
respective branes.Comment: 11 pages, LaTeX, 1 figur
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