316 research outputs found
Partially Composite Dark Matter
In a class of theories where the Higgs field emerges as a pseudo
Nambu-Goldstone boson, it is often assumed that interactions to generate the
top Yukawa coupling provide the Higgs potential as well. Such a scenario
generically requires a little cancellation in the leading contribution to the
Higgs potential, and the electroweak scale is generated by the balance between
the leading and the subleading contributions. We, instead, consider the
possibility that the contribution from the dark matter particle balances
against that from the top quark. The thermal relic of the new particle explains
the abundance of dark matter in a consistent region of the parameter space, and
the direct detection is found to be promising.Comment: 16 pages, 2 figures, v2: minor changes, references adde
Natural supersymmetric spectrum in mirage mediation
Current results of LHC experiments exclude large area of light new particle
region, namely natural parameter space, in supersymmetric extension models. One
of the possibilities for achieving the correct electroweak symmetry breaking
naturally is low scale messenger scenario. Actually, the next-to-minimal
supersymmetric standard model with TeV scale mirage mediation realizes the
natural electroweak symmetry breaking with various mass spectra. In this paper,
we show the possible mass spectrum in the scenario, e.g. degenerate and/or
hierarchical mass spectrum, and discuss these features.Comment: 37 pages, 2 figures;v2 minor chang
Can R-parity violation hide vanilla supersymmetry at the LHC?
Current experimental constraints on a large parameter space in supersymmetric
models rely on the large missing energy signature. This is usually provided by
the lightest neutralino which stability is ensured by the R-parity. However, if
the R-parity is violated, the lightest neutralino decays into the standard
model particles and the missing energy cut is not efficient anymore. In
particular, the UDD type R-parity violation induces the neutralino decay to
three quarks which potentially leads to the most difficult signal to be
searched at hadron colliders. In this paper, we study the constraints on the
R-parity violating supersymmetric model using a same-sign dilepton and a
multijet signatures. We show that the gluino and squarks lighter than a TeV are
already excluded in constrained minimal supersymmetric standard model with
R-parity violation if their masses are approximately equal. We also analyze
constraints in a simplified model with R-parity violation. We compare how
R-parity violation changes some of the observables typically used to
distinguish a supersymmetric signal from standard model backgrounds.Comment: 14 pages, 4 figure
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