4,228 research outputs found
Axion dark matter with explicit Peccei-Quinn symmetry breaking in the axiverse
It is shown that the required high quality of the Peccei-Quinn (PQ) symmetry
can be a natural outcome of the multiple QCD axion models. In the axiverse, a
hypothetical mass mixing between the QCD axions and axion-like particles (ALPs)
can occur, which leads to an interesting phenomenon called the level crossing.
In this paper, we investigate this mass mixing between one QCD axion and one
ALP with the explicit PQ symmetry breaking in the early Universe. The dynamics
of the axions and their cosmological evolutions when the level crossing occurs
in this scenario are studied in detail. Then we focus our attention on the
axion dark matter (DM) abundance. With several typical parameter sets for level
crossing, we find that in the presence of the explicit PQ symmetry breaking
term in the mixing, the total axion DM abundance is dominated by ALP and
significantly suppressed.Comment: 20 pages, 7 figure
New feature of low charm quark hadronization in collisions at TeV
Treating the light-flavor constituent quarks and antiquarks that can well
describe the data of light-flavor hadrons in collisions at
TeV as the underlying source of chromatically neutralizing the charm quarks of
low transverse momenta (), we show that the experimental data of
spectra of single-charm hadrons , ,
and at mid-rapidity in the low range
( GeV/) in collisions at TeV can
be well understood by the equal-velocity combination of perturbatively-created
charm quarks and those light-flavor constituent quarks and antiquarks. This
suggests a possible new scenario of low charm quark hadronization, in
contrast to the traditional fragmentation mechanism, in collisions at LHC
energies. This is also another support for the exhibition of the effective
constituent quark degrees of freedom for the small parton system created in
collisions at LHC energies.Comment: 7 pages, 5 figure
Chaos-based wireless communication resisting multipath effects
This work is supported by NSFC (China) under Grants No. 61401354, No. 61172070, and No. 61502385; by the Innovative Research Team of Shaanxi Province under Grant No. 2013KCT-04; and by Key Basic Research Fund of Shaanxi Province under Grant No. 2016JQ6015.Peer reviewedPublisher PD
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