2006/11/30 by Tatsuo Kobayashi, Hans Peter Nilles, Felix Plöger +2 · 1 citation
Physics and Astronomy · #hep-ph #hep-th
paper · pdf · doi:10.1016/j.nuclphysb.2007.01.018
published as Nucl.Phys.B768:135-156,2007 · 27 pages, 4 figures, v2: matches version published in Nuclear Physics B
arxiv created 2007/01/31 · arxiv updated 2009/12/01
We study the origin of non-Abelian discrete flavor symmetries in superstring theory. We classify all possible non-Abelian discrete flavor symmetries which can appear in heterotic orbifold models. These symmetries include D4 and Delta(54). We find that the symmetries of the couplings are always larger than the symmetries of the compact space. This is because they are a consequence of the geometry of the orbifold combined with the space group selection rules of the string. We also study possible breaking patterns. Our analysis yields a simple geometric understanding of the realization of non-Abelian flavor symmetries.