# Jumping Spectra and Vanishing Couplings in Heterotic Line Bundle Standard Models

## TL;DR

This paper explores how moduli stabilization and topological constraints influence the spectrum and couplings in heterotic Line Bundle Standard Models on Calabi-Yau threefolds, revealing common occurrences of spectrum jumps and coupling vanishing.

## Contribution

It provides a detailed analysis of the impact of moduli fixing and topological effects on the physical properties of heterotic line bundle models, highlighting their prevalence.

## Key findings

- Spectrum jumps are common due to moduli stabilization.
- Many couplings vanish because of topological constraints.
- Both effects significantly influence model phenomenology.

## Abstract

We study two aspects of the physics of heterotic Line Bundle Standard Models on smooth Calabi-Yau threefolds. First, we investigate to what degree modern moduli stabilization scenarios can affect the standard model spectrum in such compactifications. Specifically, we look at the case where some of the complex structure moduli are fixed by a choice of hidden sector bundle. In this context, we study the frequency with which the system tends to be forced to a point in moduli space where the cohomology groups determining the spectrum in the standard model sector jump in dimension. Second, we investigate to what degree couplings, that are permitted by all of the obvious symmetries of the theory, actually vanish due to certain topological constraints associated to their higher dimensional origins. We find that both effects are prevalent within the data set of heterotic Line Bundle Standard Models studied.