Dark Matter from 't Hooft Anomaly Matching

TL;DR

This paper explores how composite fermions in confining gauge theories, stabilized by anomaly matching and accidental symmetries, can serve as dark matter candidates with specific models linking them to Standard Model particles.

Contribution

It introduces explicit models based on 't Hooft anomaly matching where dark matter is composite, charged under the SM, and its stability is automatically ensured by the theory's symmetries.

Findings

Models produce dark matter as composite states with SM charges.

Composite dark matter can resemble elementary particles like Winos and neutralinos.

Phenomenology depends critically on compositeness effects.

Abstract

Light fermions that arise as composite states in confining gauge theories are stable due to fermion number conservation. This leads to Dark Matter candidates that behave similarly to elementary DM but where the cosmological stability arises automatically from the accidental symmetries of the theory. We present explicit models based on 't Hooft anomaly matching conditions where DM is charged under the SM. For example an SU(N) gauge theory with fermions in the adjoint rep and triplet of SU(2)$_L$ gives rise to DM made of multiple "Wino" triplets, while SO(N) gauge theories with $N_F=N-4$ flavors produce neutralino-like systems or SM quintuplets. Compositeness effects are crucial to determine the phenomenology.