4,859 research outputs found
Neutral kaon photoproduction on the deuteron
Neutral kaon photoproduction on the deuteron has been investigated by
including the final state effects and compared with the experimental data.
Comparison shows that the models used in this calculation can reproduce the
data in the channel regions fairly well but still give over
predictions in the channel. It seems that the tensor target
asymmetries are more suitable for studying the final state effects. The
extractions of the elementary photoproduction amplitude are also demonstrated.Comment: 6 pages, 6 figures, talk given by A. Salam at Fourth Asia-Pacific
Conference on Few-Body Problems in Physics 2008 (APFB08), Depok, Indonesia,
August 19-23, 200
The electronic transport properties and microstructure of carbon nanofiber/epoxy composites
Carbon nanofibres (CNF) were dispersed into an epoxy resin using a
combination of ultrasonication and mechanical mixing. The electronic transport
properties of the resulting composites were investigated by means of impedance
spectroscopy. It was found that a very low critical weight fraction (pc = 0.064
wt %) which may be taken to correspond to the formation of a tunneling
conductive network inside the matrix. The insulator-to-conductor transition
region spanned about one order of magnitude from 0.1 to 1 wt %. Far from the
transition, the conductivity increased by two orders of magnitude. This
increase and the low value of the conductivity were explained in terms of the
presence of an epoxy film at the contact between CNF. A simple model based on
the CNF-CNF contact network inside the matrix was proposed in order to evaluate
the thickness of that film.Comment: 7 page
The precedence of syntax in the rapid emergence of human language in evolution as defined by the integration hypothesis
Our core hypothesis is that the emergence of human language arose very rapidly from the linking of two pre-adapted systems found elsewhere in the animal world—an expression system, found, for example, in birdsong, and a lexical system, suggestively found in non-human primate calls (Miyagawa et al., 2013, 2014). We challenge the view that language has undergone a series of gradual changes—or a single preliminary protolinguistic stage—before achieving its full character. We argue that a full-fledged combinatorial operation Merge triggered the integration of these two pre-adapted systems, giving rise to a fully developed language. This goes against the gradualist view that there existed a structureless, protolinguistic stage, in which a rudimentary proto-Merge operation generated internally flat words. It is argued that compounds in present-day language are a fossilized form of this prior stage, a point which we will question
Electron Correlations in the Quasi-Two-Dimensional Organic Conductor -(BEDT-TTF)I investigated by C NMR
We report a C-NMR study on the ambient-pressure metallic phase of the
layered organic conductor -(BEDT-TTF)I [BEDT-TTF:
bisethylenedithio-tetrathiafulvalene], which is expected to connect the physics
of correlated electrons and Dirac electrons under pressure. The orientation
dependence of the NMR spectra shows that all BEDT-TTF molecules in the unit
cell are to be seen equivalent from a microscopic point of view. This feature
is consistent with the orthorhombic symmetry of the BEDT-TTF sublattice and
also indicates that the monoclinic sublattice, which should make three
molecules in the unit cell nonequivalent, is not practically influential on the
electronic state in the conducting BEDT-TTF layers at ambient pressure. There
is no signature of charge disproportionation in opposition to most of the
-type BEDT-TTF salts.
The analyses of NMR Knight shift, , and the nuclear spin-lattice
relaxation rate, , revealed that the degree of electron correlation,
evaluated by the Korringa ratio [)], is in an
intermediate regime. However, NMR relaxation rate is enhanced above
200K, which possibly indicates that the system enters into a quantum
critical regime of charge-order fluctuations as suggested theoretically.Comment: 19pages, 6figure
Transport criticality of the first-order Mott transition in a quasi-two-dimensional organic conductor, -(BEDT-TTF)Cu[N(CN)]Cl
An organic Mott insulator, -(BEDT-TTF)Cu[N(CN)]Cl, was
investigated by resistance measurements under continuously controllable He gas
pressure. The first-order Mott transition was demonstrated by observation of
clear jump in the resistance variation against pressure. Its critical endpoint
at 38 K is featured by vanishing of the resistive jump and critical divergence
in pressure derivative of resistance, , which are consistent with the prediction of the dynamical mean field
theory and have phenomenological correspondence with the liquid-gas transition.
The present results provide the experimental basis for physics of the Mott
transition criticality.Comment: 4 pages, 5 figure
Lambda-N scattering length from the reaction gamma d -> K^+ Lambda n
The perspects of utilizing the strangeness-production reaction gamma d -> K^+
Lambda n for the determination of the Lambda n low-energy scattering parameters
are investigated. The spin observables that need to be measured in order to
isolate the Lambda n singlet (1S0) and triplet (3S1) states are identified.
Possible kinematical regions where the extraction of the Lambda n scattering
lengths might be feasible are discussed.Comment: 8 pages, 4 figure
Inclusive and exclusive photoproduction on the deuteron: - and -threshold phenomena
Inclusive and exclusive photoproduction on the deuteron are
investigated theoretically. Modern hyperon-nucleon forces and a recently
updated kaon photoproduction operator for the process are
used. Sizable effects of the hyperon-nucleon final state interaction are found
near the and thresholds in the inclusive reaction.
Angular distributions for the exclusive process show clear final state
interaction effects in certain kinematic regions. Precise data especially for
the inclusive process around the threshold would help to clarify
the strength and property of the interaction.Comment: 14 pages, 10 figure
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