Seung Lee: A Visible Custodially Warped-GUT Dark Matter Sector & Astrophysical Implications

A Visible Custodially Warped-GUT Dark Matter Sector & Astrophysical Implications

Seung Lee, Weizmann Institute

The recent/future experimental searches for anti-matter in
cosmic rays up to energies of roughly a TeV motivates studies of particle physics models of dark matter (DM) where DM annihilation dynamics could yield observed signal. We explore this possibility within the warped extra dimensional grand unified framework in which proton stability implies a possible DM candidate. We find that exchange of order 100 GeV radion can result in a sizable Sommerfeld enhancement of the annhilation cross-section. The enhancement is a fairly generic feature of the framework, associated with the pseudo Goldstone boson nature of the radion field. Thus, unlike in various proposed models, no dark sector is required to obtain boosted annihilation rates. Custodial symmetry for Z → b ̄b is required in order to ameliorate little hierarchy problem of the realistic bulk warped models. We show how to incorporate it into partially unified, Pati-Salam group, and into full unification via non-canonical representations. This representations also allow us to decouple the Z′-DM couplings and obtained a correct DM relic density. Looking at robust cosmic ray observables (suggested recently in arXiv:0907.1686) we find a future signal in the anti-proton to proton flux consistent with current constraints. The custodial symmetry allows for emergence of composite taus which may lead to observed signal in cosmic rays and the LHC. However, this possibility requires additional DM sources.