383 research outputs found
Cyclic Permutations in Kazama-Suzuki String Models
Moddings by cyclic permutation symmetries are performed in 4-dimensional
strings, built up from N=2 coset models of the type . For some exemplifying cases, the massless chiral and antichiral states
of are computed. The extent of the equivalence between different
conformal invariant theories which possess equal chiral rings is analyzed.Comment: 26 pages, LaTex fil
N=2 Coset Compactifications with Non-Diagonal Invariants
We consider 4-dimensional string models obtained by tensoring N=2 coset
theories with non-diagonal modular invariants. We present results from a
systematic analysis including moddings by discrete symmetries.Comment: 29 page
Nondiagonal Coset Models and their Poincar\'E Polynomials
coset models of the type with nondiagonal
modular invariants for both and are considered. Poincar\'e
polynomials of the corresponding chiral rings of these algebras are
constructed. They are used to compute the number of chiral generations of the
associated string compactifications. Moddings by discrete symmetries are also
discussed.Comment: 22 pages, (RevTex), preprint GTCRG-92-1 and CNEA-CAB-039/92. % Minor
changes in the result
On Susy Standard-like models from orbifolds of D=6 Gepner orientifolds
As a further elaboration of the proposal of Ref. [1] we address the
construction of Standard-like models from configurations of stacks of
orientifold planes and D-branes on an internal space with the structure
. As a first step, the construction of
D=6 Type II B orientifolds on Gepner points, in the diagonal invariant case and
for both, odd and even, affine levels is discussed. We build up the explicit
expressions for B-type boundary states and crosscaps and obtain the amplitudes
among them. From such amplitudes we read the corresponding spectra and the
tadpole cancellation equations. Further compactification on a T^2 torus, by
simultaneously orbifolding the Gepner and the torus internal sectors, is
performed. The embedding of the orbifold action in the brane sector breaks the
original gauge groups and leads to N=1 supersymmetric chiral spectra. Whenever
even orbifold action on the torus is considered, new branes, with worldvolume
transverse to torus coordinates, must be included. The detailed rules for
obtaining the D=4 model spectra and tadpole equations are shown. As an
illustration we present a 3 generations Left-Right symmetric model that can be
further broken to a MSSM model.Comment: 40 pages, 2 figures, added references, table 3 correcte
Particle models from orientifolds at Gepner-orbifold points
We consider configurations of stacks of orientifold planes and D-branes
wrapped on a non trivial internal space of the structure {(Gepner model)^{c=3n}
x T^{2(3-n)}}/Z_N, for n=1,2,3. By performing simple moddings by discrete
symmetries of Gepner models at orienti fold points, consistent with a Z_N
orbifold action, we show that projection on D-brane configurations can be
achieved, generically leading to chiral gauge theories. Either supersymmetric
or non-supersymmetric (tachyon free) models can be obtained. We illustrate the
procedure through some explicit examples.Comment: 36 pages, no figures Corrected sign of eq. 6.26 references added,
minor correction
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