Exploring the landscape of CHL strings on Td

ANAMARIA FONT; BERNARDO FRAIMAN; MARIANA GRAÑA; CARMEN A. NÚÑEZ; HECTOR PARRA FREITAS

JOURNAL OF HIGH ENERGY PHYSICS

SPRINGER

Lugar: Berlin; Año: 2021 vol. 21

1126-6708

Compactifications of the heterotic string on special Td/Z2 orbifolds realize alandscape of string models with 16 supercharges and a gauge group on the left-movingsector of reduced rank d + 8. The momenta of untwisted and twisted states span a latticeknown as the Mikhailov lattice II(d) , which is not self-dual for d > 1. By using computeralgorithms which exploit the properties of lattice embeddings, we perform a systematicexploration of the moduli space for d ≤ 2, and give a list of maximally enhanced pointswhere the U(1)d+8 enhances to a rank d + 8 non-Abelian gauge group. For d = 1, thesegroups are simply-laced and simply-connected, and in fact can be obtained from the Dynkindiagram of E10. For d = 2 there are also symplectic and doubly-connected groups. Forthe latter we find the precise form of their fundamental groups from embeddings of latticesinto the dual of II(2). Our results easily generalize to d > 2.