Dark matter and localised fermions from spherical orbifolds?

TL;DR

This paper explores six-dimensional models with spherical orbifold extra-spaces, proposing localized fermions to address fermion spectrum issues and identifying conditions for stable dark matter candidates.

Contribution

It introduces a novel approach using localized fermions in spherical orbifold models to avoid fermion spectrum problems and analyzes dark matter stability within this framework.

Findings

Four compatible geometries for dark matter stability.

Models are under tension unless in a Higgs resonance funnel.

Collider and relic density constraints are combined.

Abstract

We study a class of six-dimensional models based on positive curvature surfaces (spherical 2-orbifolds) as extra-spaces. Using the Newman-Penrose formalism, we discuss the particle spectrum in this class of models. The fermion spectrum problem, which has been addressed with flux compactifications in the past, can be avoided using localised fermions. In this framework, we find that there are four types of geometry compatible with the existence of a stable dark matter candidate and we study the simplest case in detail. Using the complementarity between collider resonance searches and relic density constraints, we show that this class of models is under tension, unless the model lies in a funnel region characterised by a resonant Higgs s-channel in the dark matter annihilation.