160 research outputs found
ATLAS on-Z Excess Through Vector-Like Quarks
We investigate the possibility that the excess observed in the leptonic-jets +\slashed{E}_T ATLAS SUSY search is due to pair productions of a
vector-like quark decaying to the first-generation quarks and boson. We
find that the excess can be explained within the 2 (up to 1.4)
level while evading the constraints from the other LHC searches. The preferred
range of the mass and branching ratio are GeV and -, respectively.Comment: 8 pages, 2 figure
Heavy WIMP through Higgs portal at the LHC
LHC constraints on Higgs-portal WIMPs are studied. Scalar, vector and
anti-symmetric tensor fields are considered. They are assumed to be heavier
than a half of the Higgs boson mass. We investigate 8 TeV LHC results on
signatures of the vector boson fusion, mono-jet and associated production of
the boson, which proceed via virtual exchange of the Higgs boson. We show
that Higgs-portal interactions of the vector and tensor WIMPs are constrained
to be less than 0.43 and 0.16, respectively, while those for the scalar are
very weak. Prospects of the 14 TeV LHC are also discussed.Comment: 14 pages, 3 figure
Unitarity Bounds on Dark Matter Effective Interactions at LHC
The perturbative unitarity bound is studied in the monojet process at LHC.
The production of the dark matter is described by the low-energy effective
theory. The analysis of the dark matter signal is not validated, if the
unitarity condition is violated. It is shown that the current LHC analysis the
effective theory breaks down, at least, when the dark matter is lighter than
O(100) GeV. Future prospects for = 14 TeV are also discussed. The
result is independent of physics in high energy scales.Comment: 14 pages, 12 figures; v2: footnotes and references are added; figures
are slightly change
Radiative CP Phases in Supergravity Theories
In this letter, we point out that possible sources of CP violation originate
from radiative corrections to soft terms which are ubiquitous in supergravity
theories and also in other high-energy frameworks of supersymmetry breaking.
With these radiative phases of gaugino masses and scalar couplings, a complex
phase of Higgs holomorphic mass parameter is generated via
renormalization-group running down to low energy. It is found that its phase
value is mainly controlled by wino as well as gluino, which generally receive
different radiative corrections to their complex phases, even if the leading
part of mass parameters follow from the universality hypothesis. The
radiatively generated phases are constrained by the existing experimental
bounds on electric dipole moments, and may be detectable in future
measurements. They are also found to be available for the cancellation
mechanism to be worked.Comment: 14 pages, 5 figures, references adde
Future Prospects for Stau in Higgs Coupling to Di-photon
We study future prospects of the stau which contributes to the Higgs coupling
to di-photon. The coupling is sensitive to new physics and planned to be
measured at percent levels in future colliders. We show that, if the excess of
the coupling is measured to be larger than 4 %, the lightest stau is predicted
to be lighter than about 200 GeV by taking vacuum meta-stability conditions
into account. Such a stau can be discovered at ILC. Moreover, we show how
accurately the stau contribution to the coupling can be reconstructed from the
information that is available at ILC. We also argue that, if the stau mixing
angle is measured, the mass of the heaviest stau can be predicted by measuring
the Higgs coupling, even when the heaviest stau is not yet discovered at the
early stage of ILC.Comment: 16 pages, 4 figures, 1 table; references added, to be published in
JHE
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