Astrophysical Implications of a Visible Dark Matter Sector from a Custodially Warped-GUT

TL;DR

This paper investigates how warped extra-dimensional models with radion-mediated Sommerfeld enhancement can produce detectable cosmic ray anti-matter signals from dark matter annihilation, consistent with collider and direct detection constraints.

Contribution

It introduces a warped GUT framework with a custodial symmetry that naturally enhances dark matter annihilation signals without requiring a dark sector, and explores observable cosmic ray and collider signatures.

Findings

Potential future anti-proton flux ratio signals in cosmic rays.

A viable dark matter relic density consistent with direct detection bounds.

Strong LHC signals from KK particles coupled to tau leptons.

Abstract

We explore, within the warped extra dimensional framework, the possibility of finding anti-matter signals in cosmic rays (CRs) from dark matter (DM) annihilation. Exchange of order 100 GeV radion, an integral part of our setup, generically results in Sommerfeld enhancement of the annihilation rate for TeV DM mass. No dark sector is required to obtain boosted annihilation cross sections. A mild hierarchy between the radion and DM masses can be natural due to the pseudo-Goldstone boson nature of the radion. Implications of Sommerfeld enhancement in warped grand unified theory (GUT) models, where proton stability implies a DM candidate, are studied. We show, via partially unified Pati-Salam group, how to incorporate a custodial symmetry for Z->b\bar b into the GUT framework such that a few TeV Kaluza-Klein (KK) mass scale is allowed by precision tests. The model with smallest fully unified SO(10) representation allows us to decouple the DM from the electroweak sector. Thus, a correct DM relic density is obtained and direct detection bounds are satisfied. Looking at robust CR observables, a possible future signal in the \bar p / p flux ratio is found. We show how to embed a similar custodial symmetry for the right handed tau, allowing it to be strongly coupled to KK particles. Such a scenario might lead to observed signal in CR positrons; however, the DM candidate in this case can not constitute all of the DM in the universe. Independently of the above, the strong coupling between KK particles and tau's can lead to striking LHC signals.