20 research outputs found
Warped Radion Dark Matter
Warped scenarios offer an appealing solution to the hierarchy problem. We
consider a non-trivial deformation of the basic Randall-Sundrum framework that
has a KK-parity symmetry. This leads to a stable particle beyond the Standard
Model, that is generically expected to be the first KK-parity odd excitation of
the radion field. We consider the viability of the KK-radion as a DM candidate
in the context of thermal and non-thermal production in the early universe. In
the thermal case, the KK-radion can account for the observed DM density when
the radion decay constant is in the natural multi-TeV range. We also explore
the effects of coannihilations with the first KK excitation of the RH top, as
well as the effects of radion-Higgs mixing, which imply mixing between the
KK-radion and a KK-Higgs (both being KK-parity odd). The non-thermal scenario,
with a high radion decay constant, can also lead to a viable scenario provided
the reheat temperature and the radion decay constant take appropriate values,
although the reheat temperature should not be much higher than the TeV scale.
Direct detection is found to be feasible if the DM has a small (KK-parity odd)
Higgs admixture. Indirect detection via a photon signal from the galactic
center is an interesting possibility, while the positron and neutrino fluxes
from KK-radion annihilations are expected to be rather small. Colliders can
probe characteristic aspects of the DM sector of warped scenarios with
KK-parity, such as the degeneracy between the radion and the KK-radion (DM)
modes.Comment: 43 pages, 16 figures; added reference
Warped Universal Extra Dimensions
We consider a 5D warped scenario with a KK-parity symmetry, where the
non-trivial warping arises from the dynamics that stabilizes the size of the
extra dimension. Generically, the lightest Kaluza-Klein (KK) particle is the
first excitation of the radion field, while the next-to-lightest Kaluza-Klein
particle is either the first excitation of the (RH) top quark or the first
KK-parity odd Higgs. All these masses are expected to be of order the
electroweak scale. We present simple analytical expressions for the masses and
wavefunctions of the lowest lying KK modes, and derive the Feynman rules
necessary for phenomenological applications. The framework allows to
interpolate between a strongly warped scenario a la Randall-Sundrum (RS), and a
weakly warped scenario that shares properties of both RS and Universal Extra
Dimensions models.Comment: 41 pages, 13 figures. Minor comments added. Published versio