Astrophysical implications of a visible dark matter sector from a custodially warped GUT

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. We find that exchange of order 100 GeV radion, an integral part of this class of models, generically results in a sizable Sommerfeld enhancement of the annihilation rate for DM mass at the TeV scale. No ad-hoc dark sector is required to obtain boosted annihilation cross sections and hence signals. Such a mild hierarchy between the radion and DM masses can be natural due to the pseudo-Goldstone boson nature of the radion. We study the implications of a Sommerfeld enhancement specifically in warped grand unified theory (GUT) models, where proton stability implies a DM candidate. We show, via partially unified Pati-Salam group, how to incorporate a custodial symmetry for Z → bb into the GUT framework such that a few TeV Kaluza-Klein (KK) mass scale is allowed by electroweak precision tests. Among such models, the one with the smallest SO(10) (fully unified) representation, with SU (5) hypercharge normalization, allows us to decouple the DM from the electroweak gauge bosons. Thus, a correct DM relic density can be obtained and direct detection bounds are satisfied.Looking at robust CR observables, we find a possible future signal in thep/p flux ratio consistent with current constraints. Using a different choice of representations, we show how to embed in this GUT model 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. As an aside and independent of GUT or DM model, the strong coupling between KK particles and tau's can lead to striking LHC signals.

Scalar simplified models for dark matter

“…This is the well-known "Higgs Portal" scenario for dark matter [130][131][132][133][134][135][136][137][138][139][140][141][142][143][144][145][146][147][148][149] (similarly, one could consider the "dilaton" portal [150][151][152][153]). …”

Ultravisible warped model from flavor triviality and improved naturalness

“…However, one could imagine embedding the above theory into some form of unification model (for an SO(10) grand unified theory (GUT) see for example [74][75][76][77][78][79][80]), which would explain why the couplings are related to each other. 6 Finite radiative corrections to these quantities are proportional to the bulk masses themselves [81].…”

Higgs phenomenology in warped extra dimensions with a fourth generation

“…(31) and (32) to compute the flavor violating Higgs Yukawa couplings, parametrized by the a ij 's as defined in Eq. (35).…”

“…An additional benefit of the extension of a fourth generation in warped models, could be the inclusion of the fourth generation neutrino, which may become a novel dark matter candidate [34], typically missing in minimal models (see however [35] for different approaches).…”