957 research outputs found
Search for the Top Partner at the LHC using Multi-b-Jet Channels
Vector-like quarks are introduced in various new physics models beyond the
standard model (SM) at the TeV scale. We especially consider the case that the
quark is singlet (triplet) under the SU(2) (SU(3)) gauge group and
couples only to the third generation quarks of the SM. The vector-like quark of
this kind is often called a top partner. The top partoner decays into
and . In the ATLAS and CMS collaborations, the top partner has
been searched in the final states of and , while the search based on
the decay mode has not been started yet. However, the decay into
is important since it is significantly enhanced if some strong dynamics
exists in the TeV scale. In the presence of a light higgs boson, the decay mode
followed by produces three bottom quarks. We study
the sensitivity for the top partner using multi-b-jet events at the 8 TeV run
of the LHC experiment. The multi-b-jet eventss turn out to play a complementary
role to the existing and searches by the ATLAS and CMS
collaborations.Comment: 26 pages, 9 figures, 10 Table
High-Scale SUSY Breaking Models in light of the BICEP2 Result
The large value of the tensor-to-scalar ratio in the cosmic microwave
background radiation reported by the BICEP2 collaboration gives strong impact
on models of supersymmetry (SUSY). The large ratio indicates inflation with a
high-energy scale and thus a high reheating temperature in general, and various
SUSY models suffer from the serious gravitino and Polonyi problems. In this
article, we discuss a class of the high-scale SUSY breaking models which are
completely free from those problems. With especially focusing on the dark
matter relic abundance, we examine how the BICEP2 result narrows down the
parameter space of the models, assuming the simplest chaotic inflation model.
We find that the mass of the dark matter is predicted to be less than about 1
TeV thanks to the non-thermal production in the early universe through the
decay of abundant gravitinos produced after the reheating process. We also
discuss implications in some details to dark matter searches at collider and
indirect dark matter detection experiments.Comment: 17 pages, 6 figure
Indirect Probe of Electroweak-Interacting Particles at Future Lepton Colliders
Various types of electroweak-interacting particles, which have non-trivial
charges under the gauge symmetry,
appear in various extensions of the Standard Model. These particles are good
targets of future lepton colliders, such as the International Linear Collider
(ILC), the Compact LInear Collider (CLIC) and the Future Circular Collider of
electrons and positrons (FCC-ee). An advantage of the experiments is that, even
if their beam energies are below the threshold of the production of the new
particles, quantum effects of the particles can be detected through high
precision measurements. We estimate the capability of future lepton colliders
to probe electroweak-interacting particles through the quantum effects, with
particular focus on the wino, the Higgsino and the so-called minimal dark
matters, and found that a particle whose mass is greater than the beam energy
by 100-1000 GeV is detectable by measuring di-fermion production cross sections
with \% accuracy. In addition, with the use of the same analysis, we
also discuss the sensitivity of the future colliders to model independent
higher dimensional operators, and found that the cutoff scales corresponding to
the operators can be probed up to a few ten TeV
Pr内包カゴ状化合物PrIr2Zn20における超伝導と四極子秩序
内容の要約広島大学(Hiroshima University)博士(理学)Doctor of Sciencedoctora
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