805 research outputs found
Matching the BPS Spectra of Heterotic - Type I - Type I' Strings
We give a detailed discussion of the matching of the BPS states of heterotic,
type I and type I' theories in d=9 for general backgrounds. This allows us to
explicitly identify these (composite) brane states in the type I' theory that
lead to gauge symmetry enhancement at critical points in moduli space. An
example is the enhancement of to .Comment: 11 pages; minor typos in eq. (3), (4) and on page 9 have been
corrected; two footnotes taking into account additional references have been
added; version to appear in Physics Letters
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
Effect on the electron EDM due to abelian gauginos in SUSY extra U(1) models
The electric dipole moment of an electron (EDME) is investigated in the
supersymmetric extra U(1) models. Neutralino sector is generally extended in
these models and then the neutralino contribution will be important for the
analysis of the EDME. Kinetic term mixings of abelian gauginos are taken into
account in our analysis. Numerical results for the extra U(1) models show that
the EDME can be affected by the extra U(1) in a certain range of soft
supersymmetry breaking parameters even if the extra U(1) gauge boson is heavy.
The EDME may be a clue to find an extended gauge structure in the
supersymmetric models.Comment: 16 pages, latex, 3 figure
Dilatonic Inflation and SUSY Breaking in String-inspired Supergravity
The theory of inflation will be investigated as well as supersymmetry
breaking in the context of supergravity, incorporating the target-space duality
and the nonperturbative gaugino condensation in the hidden sector. We found an
inflationary trajectory of a dilaton field and a condensate field which breaks
supersymmetry at once. The model satisfies the slow-roll condition which solves
the eta-problem. When the particle rolls down along the minimized trajectory of
the potential V(S,Y) at a duality invariant point of T=1, we can obtain the
e-fold value \sim 57. And then the cosmological parameters obtained from our
model well match the recent WMAP data combined with other experiments. This
observation suggests one to consider the string-inspired supergravity as a
fundamental theory of the evolution of the universe as well as the particle
theory.Comment: 10 pages, 4 eps figures. Typos and references corrected. Final
version to appear in Mod. Phys. Lett.
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