Loop-Corrected Compactifications of the Heterotic String with Line Bundles

TL;DR

This paper analyzes heterotic string compactifications on Calabi-Yau manifolds with line bundle structures, computing one-loop corrections to gauge couplings and Fayet-Iliopoulos terms, and presents explicit models including one with Standard Model symmetry.

Contribution

It introduces loop-corrected compactification models with line bundles, providing explicit tadpole-free examples and analyzing their low-energy consequences.

Findings

Computed one-loop gauge couplings and Fayet-Iliopoulos terms.

Constructed explicit models with realistic gauge groups.

Identified models with Standard Model gauge symmetry.

Abstract

We consider the E8 x E8 heterotic string theory compactified on Calabi-Yau manifolds with bundles containing abelian factors in their structure group. Generic low energy consequences such as the generalised Green-Schwarz mechanism for the multiple anomalous abelian gauge groups are studied. We also compute the holomorphic gauge couplings and induced Fayet-Iliopoulos terms up to one-loop order, where the latter are interpreted as stringy one-loop corrections to the Donaldson-Uhlenbeck-Yau condition. Such models generically have frozen combinations of Kaehler and dilaton moduli. We study concrete bundles with structure group SU(N) x U(1)^M yielding quasi-realistic gauge groups with chiral matter given by certain bundle cohomology classes. We also provide a number of explicit tadpole free examples of bundles defined by exact sequences of sums of line bundles over complete intersection Calabi-Yau spaces. This includes one example with precisely the Standard Model gauge symmetry.