53,067 research outputs found
The Coulomb interaction and the inverse Faddeev-Popov operator in QCD
We give a proof of a local relation between the inverse Faddeev-Popov
operator and the non-Abelian Coulomb interaction between color charges
Geochemistry and petrogenesis of volcanic rocks from Daimao Seamount (South China Sea) and their tectonic implications
The South China Sea (SCS) experienced three episodes of seafloor spreading and left three fossil spreading centers presently located at 18°N, 17°N and 15.5°N. Spreading ceased at these three locations during magnetic anomaly 10, 8, and 5c, respectively. Daimao Seamount (16.6. Ma) was formed 10. my after the cessation of the 17°N spreading center. Volcaniclastic rocks and shallow-water carbonate facies near the summit of Daimao Seamount provide key information on the seamount's geologic history. New major and trace element and Sr-Nd-Pb isotopic compositions of basaltic breccia clasts in the volcaniclastics suggest that Daimao and other SCS seamounts have typical ocean island basalt-like composition and possess a 'Dupal' isotopic signature. Our new analyses, combined with available data, indicate that the basaltic foundation of Daimao Seamount was formed through subaqueous explosive volcanic eruptions at 16.6. Ma. The seamount subsided rapidly (>. 0.12. mm/y) at first, allowing the deposition of shallow-water, coral-bearing carbonates around its summit and, then, at a slower rate (<. 0.12. mm/y). We propose that the parental magmas of SCS seamount lavas originated from the Hainan mantle plume. In contrast, lavas from contemporaneous seamounts in other marginal basins in the western Pacific are subduction-related
Dark viscous fluid described by a unified equation of state in cosmology
We generalize the CDM model by introducing a unified EOS to describe
the Universe contents modeled as dark viscous fluid, motivated by the fact that
a single constant equation of state (EOS) () reproduces the
CDM model exactly. This EOS describes the perfect fluid term, the
dissipative effect, and the cosmological constant in a unique framework and the
Friedmann equations can be analytically solved. Especially, we find a relation
between the EOS parameter and the renormalizable condition of a scalar field.
We develop a completely numerical method to perform a minimization to
constrain the parameters in a cosmological model directly from the Friedmann
equations, and employ the SNe data with the parameter measured
from the SDSS data to constrain our model. The result indicates that the
dissipative effect is rather small in the late-time Universe.Comment: 4 pages, 2 figures. v2: new materials added. v3: matches the version
to appear in IJMP
Interpretations and Implications of the Top Quark Rapidity Asymmetries and
Forward-backward asymmetries and are observed in the
top quark rapidity distribution and in the rapidity distribution of charged
leptons from top quark decay at the Tevatron proton-antiproton collider,
and a charge asymmetry is seen in proton-proton collisions at the Large
Hadron Collider (LHC). In this paper, we update our previous studies of the
Tevatron asymmetries using the most recent data. We provide expectations for
at the LHC based first on model independent extrapolations from the
Tevatron, and second based on new physics models that can explain the Tevatron
asymmetries. We examine the relationship of the two asymmetries and
. We show their connection through the spin correlation
between the charged lepton and the top quark with different polarization
states. We show that the ratio of the two asymmetries provides independent
insight into new physics models that are invoked to fit the top quark
asymmetry. We emphasize the value of the measurement of both asymmetries, and
we conclude that a model which produces more right-handed than left-handed top
quarks is favored by the present Tevatron data.Comment: Some figures changed. A typo in appendix fixed. Published in Physical
Review
Electrodynamic response of type II Weyl semimetals
Weyl fermions play a major role in quantum field theory but have been quite
elusive as fundamental particles. Materials based on quasi two-dimensional
bismuth layers were recently designed and provide an arena for the study of the
interplay between anisotropic Dirac fermions, magnetism and structural changes,
allowing the formation of Weyl fermions in condensed matter. Here, we perform
an optical investigation of YbMnBi, a representative type II Weyl
semimetal, and contrast its excitation spectrum with the optical response of
the more conventional semimetal EuMnBi. Our comparative study allows us
disentangling the optical fingerprints of type II Weyl fermions, but also
challenge the present theoretical understanding of their electrodynamic
response
Superheavy Supersymmetry from Scalar Mass--A Parameter Fixed Points
In supersymmetric models, the well-known tension between naturalness and
experimental constraints is relieved if the squarks and sleptons of the first
two generations are superheavy, with masses of order 10 TeV, and all other
superpartners are light, with masses of order 1 TeV. We show that even if all
scalar masses and trilinear A parameters are of order 10 TeV at some high
scale, a mass-squared hierarchy of order 400 may be generated dynamically
through renormalization group evolution. The required high energy relations are
consistent with grand unification, or, alternatively, may be realized in
moduli-dominated supersymmetry-breaking scenarios.Comment: 12 pages, 3 figure
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