New confining force solution of QCD axion domain wall problem

TL;DR

This paper proposes a new confining force in QCD axion models that prevents problematic domain walls from forming, thereby solving key cosmological issues and reducing axion dark matter contributions.

Contribution

It introduces a novel confining force that eliminates axion domain walls early, offering a new solution to longstanding cosmological problems in axion theories.

Findings

The new force generates an axion potential that erases axion strings early.

Axion walls decay before QCD effects, reducing dark matter contribution.

Addresses the cosmological domain wall problem in axion models.

Abstract

The serious cosmological problems created by the axion-string/axion-domain-wall system in standard axion models are alleviated by positing the existence of a new confining force. The instantons of this force can generate an axion potential that erases the axion strings long before QCD effects become important, thus preventing QCD-generated axion walls from ever appearing. Axion walls generated by the new confining force would decay so early as not to contribute significantly to the energy in axion dark matter.