标题： 基于NAHE的自由费米子和Type I Z2^n模型的开 descendant 显示英文标题

标题： Open Descendants of NAHE-based free fermionic and Type I Z2^n models

摘要： NAHE集合构成了现实的自由费米子模型的基础，对应于增强对称点处的 Z2×Z2 角球，其中 (h_{11},h_{21})=(27,3)。 或者，通过从格点上一般点处的 Z2×Z2 角球开始，并加上一个自由作用的 Z2 对合，也可以得到具有相同数据的流形。 本文研究了基于NAHE模型的流形上的I型向量量规对偶，通过纳入这种自由作用的平移来实现。 我们给出了在Type I 真空中的新模型，这些模型由 Z2^n（n=2,3）调制。 对于 n=2 的情况，Z2×Z2 结构是一种复合角球Kaluza-Klein平移排列。 分区函数提供了一个更简单的具有手征物质的谱。 对于 n=3 的情况，讨论的是 T6/(Z2×Z2) 谱的 Z2 调制。 额外的投影显示出具有手征物质的增强的闭弦和开弦扇区。 相应的，从 Z2×Z2 角球中存在的那些改变的膜堆栈。 此外，我们讨论了从开弦扇区得出的模型，有离散扭转和没有离散扭转的情况。 显示英文摘要

摘要： The NAHE-set, that underlies the realistic free fermionic models, corresponds to Z2XZ2 orbifold at an enhanced symmetry point, with (h_{11},h_{21})=(27,3). Alternatively, a manifold with the same data is obtained by starting with a Z2XZ2 orbifold at a generic point on the lattice and adding a freely acting Z2 involution. In this paper we study type I orientifolds on the manifolds that underly the NAHE-based models by incorporating such freely acting shifts. We present new models in the Type I vacuum which are modulated by Z2^n for n=2,3. In the case of n=2, the Z2XZ2 structure is a composite orbifold Kaluza-Klein shift arrangement. The partition function provides a simpler spectrum with chiral matter. For n=3, the case discussed is a Z2 modulation of the T6/(Z2 X Z2) spectrum. The additional projection shows an enhanced closed and open sector with chiral matter. The brane stacks are correspondingly altered from those which are present in the Z2 X Z2 orbifold. In addition, we discuss the models arising from the open sector with and without discrete torsion.