Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Spectra in Standard-like Z_3 Orbifold Models   General features of the spectra of matter states in all 175 models found in a
previous work by the author are discussed. Only twenty patterns of
representations are found to occur. Accomodation of the Minimal Supersymmetric
Standard Model (MSSM) spectrum is addressed. States beyond those contained in
the MSSM and nonstandard hypercharge normalization are shown to be generic,
though some models do allow for the usual hypercharge normalization found in
SU(5) embeddings of the Standard Model gauge group. The minimum value of the
hypercharge normalization consistent with accomodation of the MSSM is
determined for each model. In some cases, the normalization can be smaller than
that corresponding to an SU(5) embedding of the Standard Model gauge group,
similar to what has been found in free fermionic models. Bizzare hypercharges
typically occur for exotic states, allowing for matter which does not occur in
the decomposition of SU(5) representations---a result which has been noted many
times before in four-dimensional string models. Only one of the twenty patterns
of representations, comprising seven of the 175 models, is found to be without
an anomalous U(1). The sizes of nonvanishing vacuum expectation values induced
by the anomalous U(1) are studied. It is found that large radius moduli
stabilization may lead to the breakdown of sigma-model perturbativity. Various
quantities of interest in effective supergravity model building are tabulated
for the set of 175 models. In particular, it is found that string moduli masses
appear to be generically quite near the gravitino mass. String scale gauge
coupling unification is shown to be possible, albeit contrived, in an example
model. The intermediate scales of exotic particles are estimated and the degree
of fine-tuning is studied.

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The categories of this paper are: alg-geom
8
The categories of this paper are: hep-ex
32
The categories of this paper are: atom-ph
37
The categories of this paper are: supr-con
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The categories of this paper are: plasm-ph
23
The categories of this paper are: solv-int
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The categories of this paper are: hep-lat
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The categories of this paper are: mtrl-th
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The categories of this paper are: q-fin
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The categories of this paper are: q-bio
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The categories of this paper are: gr-qc
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The categories of this paper are: eess
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The categories of this paper are: econ
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The categories of this paper are: cmp-lg
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The categories of this paper are: dg-ga
6
The categories of this paper are: astro-ph