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

Kaustubh Agashe, Kfir Blum, Seung J. Lee, and Gilad Perez
Phys. Rev. D 81, 075012 – Published 20 April 2010

Abstract

We explore, within the warped extra dimensional framework, the possibility of finding antimatter 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 a partially unified Pati-Salam group, how to incorporate a custodial symmetry for Zbb¯ 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 the p¯/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 an observed signal in CR positrons; however, the DM candidate in this case cannot constitute all of the DM in the Universe. As an aside and independent of the GUT or DM model, the strong coupling between KK particles and tau’s can lead to striking LHC signals.

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  • Received 17 January 2010

DOI:https://doi.org/10.1103/PhysRevD.81.075012

©2010 American Physical Society

Authors & Affiliations

Kaustubh Agashe1, Kfir Blum2, Seung J. Lee2, and Gilad Perez2

  • 1Maryland Center for Fundamental Physics, Department of Physics, University of Maryland, College Park, Maryland 20742, USA
  • 2Department of Particle Physics and Astrophysics, Weizmann Institute of Science, Rehovot 76100, Israel

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Issue

Vol. 81, Iss. 7 — 1 April 2010

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