Spectra in standard-like Z3 orbifold models

被引:44
|
作者
Giedt, J [1 ]
机构
[1] Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA
[2] Univ Calif Berkeley, Lawrence Berkeley Lab, Theoret Phys Grp, Berkeley, CA 94720 USA
基金
美国国家科学基金会;
关键词
D O I
10.1006/aphy.2002.6231
中图分类号
O4 [物理学];
学科分类号
0702 ;
摘要
General features of the spectra of matter states in all 175 models found in a previous work by the author are discussed. Only 20 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-dimensional string models. Only one of the 20 patterns of representations, comprising seven of the 175 models, is found lobe without an anomalous U(1). The sizes of nonvanishing vacuum expectation values induced by the anomalous U(I) 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. (C) 2002 Elsevier Science (USA).
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页码:67 / 126
页数:60
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