1,581 research outputs found
Prospects for Triple Gauge Coupling Measurements at Future Lepton Colliders and the 14 TeV LHC
The production is the primary channel to directly probe the triple gauge
couplings. We first analyze the process at the
future lepton collider, China's proposed Circular Electron-Positron Collider
(CEPC). We use the five kinematical angles in this process to constrain the
anomalous triple gauge couplings and relevant dimension six operators at the
CEPC up to the order of magnitude of . The most sensible information
is obtained from the distributions of the production scattering angle and the
decay azimuthal angles. We also estimate constraints at the 14 TeV LHC, with
both 300 fb and 3000 fb integrated luminosity from the leading
lepton and azimuthal angle difference distributions in
the di-lepton channel. The constrain is somewhat weaker, up to the order of
magnitude of . The limits on the triple gauge couplings are
complementary to those on the electroweak precision observables and Higgs
couplings. Our results show that the gap between sensitivities of the
electroweak and triple gauge boson precision can be significantly decreased to
less than one order of magnitude at the 14 TeV LHC, and that both the two
sensitivities can be further improved at the CEPC.Comment: 36 pages, 5 figures, 8 tables, version to appear in JHE
Type-III two Higgs doublet model plus a pseudoscalar confronted with , muon and dark matter
In this work, we introduce an extra singlet pseudoscalar into the Type-III
two Higgs doublet model (2HDM) which is supposed to solve a series of problems
in the modern particle-cosmology. With existence of a light pseudoscalar, the
excess measured at CMS and as well as the
anomaly could be simultaneously explained within certain parameter spaces that
can also tolerate the data on the flavor-violating processes
and Higgs decay gained at LHC. Within the same
parameter spaces, the DM relic abundance is well accounted. Moreover, the
recently observed Galactic Center gamma ray excess(GCE) is proposed to realize
through dark matter(DM) pair annihilations, and in this work, the scenario of
the annihilation being mediated by the pseudoscalar is also addressed.Comment: 14 pages, 8 figures, version to appear in NP
Two component dark matter with multi-Higgs portals
With the assistance of two extra groups, i.e., an extra hidden gauge group
and a global group, we propose a two component dark matter
(DM) model. After the symmetry being broken, we obtain
both the vector and scalar DM candidates. The two DM candidates communicate
with the standard model (SM) via three Higgs as multi-Higgs portals. The three
Higgs are mixing states of the SM Higgs, the Higgs of the hidden sector and
real part of a supplement complex scalar singlet. We study relic density and
direct detection of DM in three scenarios. The resonance behaviors and
interplay between the two component DM candidates are represented through
investigating of the relic density in the parameter spaces of the two DMs
masses. The electroweak precision parameters constrains the two Higgs portals
couplings ( and ). The relevant vacuum stability and
naturalness problem in the parameter space of and are
studied as well. The model could alleviate these two problems in some parameter
spaces under the constraints of electroweak precision observables and Higgs
indirect search.Comment: 27 pages, 16 figures. Version accepted for publication in JHE
Searching for cosmic string induced stochastic gravitational wave background with the Parkes Pulsar Timing Array
We search for stochastic gravitational wave background emitted from cosmic
strings using the Parkes Pulsar Timing Array data over 15 years. While we find
that the common power-law excess revealed by several pulsar timing array
experiments might be accounted for by the gravitational wave background from
cosmic strings, the lack of the characteristic Hellings-Downs correlation
cannot establish its physical origin yet. The constraints on the cosmic string
model parameters are thus derived with conservative assumption that the common
power-law excess is due to unknown background. Two representative cosmic string
models with different loop distribution functions are considered. We obtain
constraints on the dimensionless string tension parameter
, which is more stringent by two orders of magnitude
than that obtained by the high-frequency LIGO-Virgo experiment for one model,
and less stringent for the other. The results provide the chance to test the
Grand unified theories, with the spontaneous symmetry breaking scale of
being two-to-three orders of magnitude below GeV. The pulsar timing
array experiments are thus quite complementary to the LIGO-Virgo experiment in
probing the cosmic strings and the underlying beyond standard model physics in
the early Universe.Comment: 10 pages, 8 figures, 4 tables. Comments welcom
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