Low energy effective theories of composite dark matter with real representations

TL;DR

This paper develops a low energy effective theory for composite dark matter candidates arising from real representations, including detailed treatment of Wess-Zumino-Witten terms, vector mesons, and flavor singlet effects, applicable to various theories.

Contribution

It introduces a comprehensive effective field theory framework for real-representation composite dark matter, incorporating Wess-Zumino-Witten terms, vector mesons, and flavor singlet states, with potential broad applicability.

Findings

Constructed a consistent low energy effective theory including Wess-Zumino-Witten terms.

Analyzed the impact of flavor singlet states on dark matter phenomenology.

Provided a formalism extendable to higher representations and discrete symmetry considerations.

Abstract

We consider pseudo Nambu-Goldstone bosons arising from Dirac fermions transforming in real representations of a confining gauge group as dark matter candidates. We consider a special case of two Dirac fermions and couple the resulting dark sector to the Standard Model using a vector mediator. Within this construction, we develop a consistent low energy effective theory, with special attention to Wess-Zumino-Witten term given the topologically non-trivial coset space. We furthermore include the heavier spin-0 flavour singlet state and the spin-1 vector meson multiplet, by using the Hidden Local Symmetry Lagrangian for the latter. Although we concentrate on special case of two flavours, our results are generic and can be applied to a wider variety of theories featuring real representations. We apply our formalism and comment on the effect of the flavour singlet for dark matter phenomenology. Finally, we also comment on generalisation of our formalism for higher representations and provide potential consequences of discrete symmetry breaking.