374 research outputs found
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
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
Testing ATLAS Diboson Excess with Dark Matter Searches at LHC
The ATLAS collaboration has recently reported a 2.6 sigma excess in the
search for a heavy resonance decaying into a pair of weak gauge bosons. Only
fully hadronic final states are being looked for in the analysis. If the
observed excess really originates from the gauge bosons' decays, other decay
modes of the gauge bosons would inevitably leave a trace on other exotic
searches. In this paper, we propose the use of the Z boson decay into a pair of
neutrinos to test the excess. This decay leads to a very large missing energy
and can be probed with conventional dark matter searches at the LHC. We discuss
the current constraints from the dark matter searches and the prospects. We
find that optimizing these searches may give a very robust probe of the
resonance, even with the currently available data of the 8 TeV LHC.Comment: 10 pages, 2 figures; v2: added references, fixed typos; v3: added
some clarifications and figures showing MET distributions, published versio
Indirect Probe of Electroweak-Interacting Particles with Mono-Lepton Signatures at Hadron Colliders
Electroweak-interacting massive particles (EWIMPs) exist in a broad class of
new physics models beyond the Standard Model. Searching for such particles is
one of most primary goal at the LHC and future colliders. The EWIMP generally
affects the LHC signatures through quantum corrections even without direct
productions. By measuring the Standard Model processes precisely, we can
indirectly probe the EWIMPs. In this paper, we study the current constraint and
future prospect of the EWIMPs by using the precision measurements of
mono-lepton production from the charged Drell-Yan processes at hadron
colliders. We found the mono-lepton signature can be a better probe than
dilepton signature from the neutral Drell-Yan processes.Comment: 10 pages, 7 figure
Probing Bino-Wino Coannihilation at the LHC
We study bino-wino coannihilation scenario in the so-called spread or
mini-split supersymmetry. We show that, in this model, a neutral wino has a
macroscopic decay length in a wide range of parameter space. This
characteristic feature could be observed as a displaced vertex plus missing
transverse energy event at the LHC. In this paper, we study the current
constraints and future prospects on the scenario based on the displaced vertex
search performed by the ATLAS collaboration. It is found that a sizable
parameter region can be probed at the 8 TeV LHC run. This search strategy will
considerably extend its reach at the next stage of the LHC running, and thus
play a crucial role to examine a possibility of bino dark matter in the
mini-split type supersymmetric models.Comment: 21 pages, 7 figures; version accepted for publication in JHE
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