On The Warped Heterotic Axion

TL;DR

This paper investigates the axion in warped heterotic string backgrounds, showing that its decay constant depends on the warped throat's mass scale, and proposes a natural mechanism for realizing the axion within specific bounds.

Contribution

It constructs a novel AdS-like geometry in heterotic string theory and links the axion decay constant to the longest warped throat's mass scale.

Findings

f_a is determined by the longest throat's mass scale

A new AdS-like heterotic geometry is constructed

The model suggests a natural way to achieve the required f_a range

Abstract

We study the axion in a warped heterotic background. It is shown that the axion decay constant, f_a, is sensitive to the warped mass scale of the throat. As an explicit model, we construct a novel AdS-like geometry in heterotic string theory. We demonstrate that in this background f_a is given by the mass scale of the longest throat in the compactification. The question of obtaining f_a within the required bound 10^9--10^12 GeV is reduced to the construction of a throat inside the heterotic string theory compactification with warped mass scale in the above range. This provides a natural mechanism for realising the axion in heterotic string theory.