Permutation orbifolds of heterotic Gepner models

Abstract

We study orbifolds by permutations of two identical N=2 minimal models within the Gepner construction of four dimensional heterotic strings. This is done using the new N=2 supersymmetric permutation orbifold building blocks we have recently developed. We compare our results with the old method of modding out the full string partition function. The overlap between these two approaches is surprisingly small, but whenever a comparison can be made we find complete agreement. The use of permutation building blocks allows us to use the complete arsenal of simple current techniques that is available for standard Gepner models, vastly extending what could previously be done for permutation orbifolds. In particular, we consider (0, 2) models, breaking of SO(10) to subgroups, weight-lifting for the minimal models and B-L lifting. Some previously observed phenomena, for example concerning family number quantization, extend to this new class as well, and in the lifted models three family models occur with abundance comparable to two or four.

Heterotic line bundle standard models

“…From figure 1 we read off c 2 (T X) = (24,24,24,24,56) and from figure (2) we have c 2 (V ) = (12,12,12,12,32). With |Γ| = 2 this means that for our example…”

“…Only a relatively small number of models exhibiting a realistic massless spectrum have been constructed in this way, some with [6] and some without [5,11,18] antibranes, reflecting the considerable technical problems associated with vector bundles on smooth Calabi-Yau manifolds. They are complemented by models found in related heterotic constructions such as those based on orbifolds [19][20][21][22][23][24][25][26][27][28], on the free fermionic strings [29][30][31], and on Gepner models [32][33][34].…”

Jumping spectra and vanishing couplings in heterotic Line Bundle Standard Models

“…Later, the concept of Line Bundle Standard Models was introduced: it was realized that simple sums of line bundles could be phenomenological viable in this context [19,20]. This work is of course complemented by extensive model building efforts in other heterotic constructions, see for example [26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43]. This lead to very large numbers of heterotic models being produced with exactly the standard models charged matter content.…”

The string theory landscape

“…1(b). 160 These authors noticed however that solutions to the tadpole conditions do not generically lead to the expected anomaly free representation (5)+(10), but to more complicated solutions involving the symmetric tensor (15). One can also start with a split stack, but then more input would seem to be required.…”