Spectra in standard-like Z_3 orbifold models
- LBNL Library
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 accommodation 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. Bizarre 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-dimensiona lstring 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.
- Research Organization:
- Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, CA (US)
- Sponsoring Organization:
- USDOE Director, Office of Science. Office of High Energy and Nuclear Physics. Division of High Energy Physics; National Science Foundation
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 838525
- Report Number(s):
- LBNL--48864
- Journal Information:
- Annals of Physics, Journal Name: Annals of Physics Journal Issue: 1 Vol. 297
- Country of Publication:
- United States
- Language:
- English
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