13,968 research outputs found
The pentaquark in K-plus-d total cross section data
An analysis of -d total cross section data is undertaken to explore
possible effects of the recently observed resonance in the S=+1 hadronic system
with mass around 1.55 GeV. It is found that a structure corresponding to the
resonance is visible in the data. The width consistent with the observed
deviation from background is found to be MeV and the mass is
GeV/c for spin-parity \h^+ and \
GeV/c for \h^-. The errors are one standard deviation and statistical
only.
\Comment: 10 pages, 5 figures Replaced to correct references, add and correct
text. No change in content. More discussion of errors, increased error on
width, corrected one figur
Origin and evolution of the Amazonian craton
The Amazonian craton appears to be formed and modifed by processes much like those of the better-known Precambrian cratons, but the major events did not always follow conventional sequences nor did they occur synchronously with those of other cratons. Much of the craton's Archean style continental crust formation, recorded in granite-greenstone and high-grade terranes, occurred in the Early Proterozoic: a period of relative quiescence in many other Precambrian regions. The common Archean to Proterozoic transition in geological style did not occur here, but an analogous change from abundant marine volcanism to dominantly continental sedimentary and eruptive styles occurred later. Amazonian geology is summarized, explaining the evolution of the craton
Monte Carlo simulation of baryon and lepton number violating processes at high energies
We report results obtained with the first complete event generator for
electroweak baryon and lepton number violating interactions at supercolliders.
We find that baryon number violation would be very difficult to establish, but
lepton number violation can be seen provided at least a few hundred L violating
events are available with good electron or muon identification in the energy
range 10 GeV to 1 TeV.Comment: 40 Pages uuencoded LaTeX (20 PostScript figures included),
Cavendish-HEP-93/6, CERN-TH.7090/9
Pion double charge exchange on 4He
The doubly differential cross sections for the He
reaction were calculated using both a two-nucleon sequential single charge
exchange model and an intranuclear cascade code. Final state interactions
between the two final protons which were the initial neutrons were included in
both methods. At incident pion energies of 240 and 270 MeV the low-energy peak
observed experimentally in the energy spectrum of the final pions can be
understood only if the contribution of pion production is included. The
calculated cross sections are compared with data.Comment: 25 pages, 9 figure
Pathways to Parenting in New Zealand: Issues in Law, Policy and Practice
In New Zealand there are many ways to become a parent, including two-parent families of heterosexual and homosexual couples, single parents, adoptive parents, kin carers, wha ̄ngai arrangements, long-term fostering, guardianship and assisted reproductive technologies. In this paper we discuss the different pathways to parenthood, how they have come about, and New Zealand’s laws, policies and practices that make them possible but also challenging. Two areas of law of particular interest are the implications of the Adoption Act 1955, which continues to be discriminatory, although some of its provisions have been reinterpreted in the courts, and the Care of Children Act 2004, which introduced ‘modern’ parenting arrangements but allowed conflicts to remain with previous child care Acts. The new Home for Life policy introduced by the Ministry of Social Development will also be critically discussed, in light of its weaknesses. We conclude with implications of the varied pathways and identified gaps in our current knowledge that call for further research
An intermediate state between the kagome-ice and the fully polarized state in DyTiO
DyTiO is at present the cleanest example of a spin-ice material.
Previous theoretical and experimental work on the first-order transition
between the kagome-ice and the fully polarized state has been taken as a
validation for the dipolar spin-ice model. Here we investigate in further depth
this phase transition using ac-susceptibility and dc-magnetization, and compare
this results with Monte-Carlo simulations and previous magnetization and
specific heat measurements. We find signatures of an intermediate state between
the kagome-ice and full polarization. This signatures are absent in current
theoretical models used to describe spin-ice materials.Comment: 7 pages, 4 figure
The photon blockade effect in optomechanical systems
We analyze the photon statistics of a weakly driven optomechanical system and
discuss the effect of photon blockade under single photon strong coupling
conditions. We present an intuitive interpretation of this effect in terms of
displaced oscillator states and derive analytic expressions for the cavity
excitation spectrum and the two photon correlation function . Our
results predict the appearance of non-classical photon correlations in the
combined strong coupling and sideband resolved regime, and provide a first
detailed understanding of photon-photon interactions in strong coupling
optomechanics
Convex Functions and Spacetime Geometry
Convexity and convex functions play an important role in theoretical physics.
To initiate a study of the possible uses of convex functions in General
Relativity, we discuss the consequences of a spacetime or an
initial data set admitting a suitably defined convex
function. We show how the existence of a convex function on a spacetime places
restrictions on the properties of the spacetime geometry.Comment: 26 pages, latex, 7 figures, improved version. some claims removed,
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Pulping characteristics of Pinus caribaea from Fiji: The effect of rate of growth
Samples of Pinus caribaea Mor. var hondurensis Barr. and Golf. from Drasa and Seaqaqa in Fiji were sub-divided so that they represented the fastest and slowest growth rate on each site. It was found that the fast growing trees yielded approximately twice the volume of wood yielded by the slow growing trees. There were no significant differences in apparent wood density or chemical composition, in pulp yield or ease of digestion by the sulphate process or in the characteristics of the unbleached pulp. In the absence of better information on which to base a selection programme, the limited evidence of this trial indicates that the best policy for the forester producing pulp wood is to adopt methods and to make selections to obtain high volume production
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