162 research outputs found
Higgsino Dark Matter in High-Scale Supersymmetry
We study a supersymmetric (SUSY) Standard Model in which a Higgsino is light
enough to be dark matter, while the other SUSY particles are much heavier than
the weak scale. We carefully treat the effects of heavy SUSY particles to the
Higgsino nature, especially taking into account the renormalization effects due
to the large hierarchy between the Higgsino and the SUSY breaking scales.
Inelastic scattering of the Higgsino dark matter with a nucleus is studied, and
the constraints on the scattering by the direct detection experiments are
discussed. This gives an upper limit on the new physics scale. Bounds on the
dark matter-nucleon elastic scattering, the electric dipole moments, and direct
production of Higgsinos, on the other hand, give a lower limit. We show the
current status on the limits and discuss the future prospects.Comment: 28 pages, 12 figures. Version accepted for publication in JHE
Electroweakly-Interacting Dirac Dark Matter
We consider a class of fermionic dark matter candidates that are charged
under both the SU(2) and U(1) gauge interactions. In this case a
certain amount of dark matter-Higgs couplings, which can split the dark matter
into a pair of Majorana fermions, should be present to evade the constraints
from the dark matter direct detection experiments. These effects may be probed
by means of the dark matter-nucleus scattering via the Higgs-boson exchange
process, as well as the electric dipole moments induced by the dark matter and
its SU(2) partner fields. In this article, we evaluate them with an
effective field approach. It turns out that the constraints coming from the
experiments for the quantities have already restricted the dark matter with
hypercharge . Future experiments have sensitivities to probe this
class of dark matter candidates, and may disfavor the cases if no
signal is observed. In this case, only the and cases may be the
remaining possibilities for the SU(2) charged fermionic dark matter
candidates.Comment: 5 pages, 3 figure
Hidden Charged Dark Matter and Chiral Dark Radiation
In the light of recent possible tensions in the Hubble constant and the
structure growth rate between the Planck and other measurements, we
investigate a hidden-charged dark matter (DM) model where DM interacts with
hidden chiral fermions, which are charged under the hidden SU(N) and U(1) gauge
interactions. The symmetries in this model assure these fermions to be
massless. The DM in this model, which is a Dirac fermion and singlet under the
hidden SU(N), is also assumed to be charged under the U(1) gauge symmetry,
through which it can interact with the chiral fermions. Below the confinement
scale of SU(N), the hidden quark condensate spontaneously breaks the U(1) gauge
symmetry such that there remains a discrete symmetry, which accounts for the
stability of DM. This condensate also breaks a flavor symmetry in this model
and Nambu-Goldstone bosons associated with this flavor symmetry appear below
the confinement scale. The hidden U(1) gauge boson and hidden
quarks/Nambu-Goldstone bosons are components of dark radiation (DR) above/below
the confinement scale. These light fields increase the effective number of
neutrinos by above the confinement scale for
, resolving the tension in the measurements of the Hubble constant by
Planck and Hubble Space Telescope if the confinement scale is eV.
DM and DR continuously scatter with each other via the hidden U(1) gauge
interaction, which suppresses the matter power spectrum and results in a
smaller structure growth rate. The DM sector couples to the Standard Model
sector through the exchange of a real singlet scalar mixing with the Higgs
boson, which makes it possible to probe our model in DM direct detection
experiments. Variants of this model are also discussed, which may offer
alternative ways to investigate this scenario.Comment: 20 pages, 4 figures; v2: version accepted for publication in PL
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