14 research outputs found
The General Warped Solution with Conical Branes in Six-dimensional Supergravity
We present the general regular warped solution with 4D Minkowski spacetime in
six-dimensional gauged supergravity. In this framework, we can easily embed
multiple conical branes into the warped geometry by choosing an undetermined
holomorphic function. As an example, for the holomorphic function with many
zeroes, we find warped solutions with multi-branes and discuss the generalized
flux quantization in this case.Comment: 1+19 pages, no figure, JHEP style, version to appear in JHE
Local SU(5) Unification from the Heterotic String
We construct a 6D supergravity theory which emerges as intermediate step in
the compactification of the heterotic string to the supersymmetric standard
model in four dimensions. The theory has N=2 supersymmetry and a gravitational
sector with one tensor and two hypermultiplets in addition to the supergravity
multiplet. Compactification to four dimensions occurs on a T^2/Z_2 orbifold
which has two inequivalent pairs of fixed points with unbroken SU(5) and
SU(2)xSU(4) symmetry, respectively. All gauge, gravitational and mixed
anomalies are cancelled by the Green-Schwarz mechanism. The model has partial
6D gauge-Higgs unification. Two quark-lepton generations are localized at the
SU(5) branes, the third family is composed of split bulk hypermultiplets. The
top Yukawa coupling is given by the 6D gauge coupling, all other Yukawa
couplings are generated by higher-dimensional operators at the SU(5) branes.
The presence of the SU(2)xSU(4) brane breaks SU(5) and generates split gauge
and Higgs multiplets with N=1 supersymmetry in four dimensions. The third
generation is obtained from two split \bar{5}-plets and two split 10-plets,
which together have the quantum numbers of one \bar{5}-plet and one 10-plet.
This avoids unsuccessful SU(5) predictions for Yukawa couplings of ordinary 4D
SU(5) grand unified theories.Comment: 38 pages. v2: Typos correcte
F-theory duals of singular heterotic K3 mode
We study F-theory duals of singular heterotic K3 models that correspond to Abelian toroidal orbifolds . While our focus is on the standard embedding, we also comment on models with Wilson lines and more general gauge embeddings. In the process of constructing the duals, we work out a Weierstrass description of the heterotic toroidal orbifold models, which exhibit singularities of Kodaira type , , , and . This construction unveils properties like the instanton number per fixed point and a correlation between the orbifold order and the multiplicities in the Dynkin diagram. The results from the Weierstrass description are then used to restrict the complex structure of the F-theory Calabi–Yau threefold such that the gauge group and the matter spectrum of the heterotic theories are reproduced. We also comment on previous approaches that have been employed to construct the duality and point out the differences and limitations in our case. Our results show explicitly how the various orbifold models are connected and described in F-theory
F-Theory Duals of Singular Heterotic K3 Models
We study F-theory duals of singular heterotic K3 models that correspond to abelian toroidal orbifolds T4/ZN. While our focus is on the standard embedding, we also comment on models with Wilson lines and more general gauge embeddings. In the process of constructing the duals, we work out a Weierstrass description of the heterotic toroidal orbifold models, which exhibit singularities of Kodaira type I∗0,IV∗,III∗, and II∗. This construction unveils properties like the instanton number per fixed point and a correlation between the orbifold order and the multiplicities in the Dynkin diagram. The results from the Weierstrass description are then used to restrict the complex structure of the F-theory Calabi-Yau threefold such that the gauge group and the matter spectrum of the heterotic theories are reproduced. We also comment on previous approaches that have been employed to construct the duality and point out the differences to our case. Our results show explicitly how the various orbifold models are connected and described in F-theory