6,671 research outputs found
Chiral dynamics of -hyperons in the nuclear medium
Using SU(3) chiral perturbation theory we calculate the density-dependent
complex mean field of a -hyperon in
isospin-symmetric nuclear matter. The leading long-range -interaction arises from one-kaon exchange and from two-pion exchange with a
- or a -hyperon in the intermediate state. We find from the
conversion process at nuclear matter saturation density
fm an imaginary single-particle potential of
MeV, in fair agreement with existing empirical
determinations. The genuine long-range contributions from iterated (second
order) one-pion exchange with an intermediate - or -hyperon
sum up to a moderately repulsive real single-particle potential of
MeV. Recently measured ) inclusive spectra
related to -formation in heavy nuclei give evidence for a
-nucleus repulsion of similar size. Our results suggest that the net
effect of the short-range -interaction on the -nuclear mean
field could be small.Comment: 7 pages, 2 figures, published in: Phys. Rev. C 71, 068201 (2005
Erosive Hit-and-Run Impact Events: Debris Unbound
Erosive collisions among planetary embryos in the inner solar system can lead
to multiple remnant bodies, varied in mass, composition and residual velocity.
Some of the smaller, unbound debris may become available to seed the main
asteroid belt. The makeup of these collisionally produced bodies is different
from the canonical chondritic composition, in terms of rock/iron ratio and may
contain further shock-processed material. Having some of the material in the
asteroid belt owe its origin from collisions of larger planetary bodies may
help in explaining some of the diversity and oddities in composition of
different asteroid groups.Comment: 7 pages, 3 figure
Antikaon-nucleus dynamics: from quasibound states to kaon condensation
Coupled-channel Kbar-N dynamics near threshold and its repercussions in
few-body Kbar-nuclear systems are briefly reviewed, highlighting studies of a
K^-pp quasibound state. In heavier nuclei, the extension of mean-field
calculations to multi-Kbar nuclear and hypernuclear quasibound states is
discussed. It is concluded that strangeness in finite self-bound systems is
realized through hyperons, with no room for kaon condensation.Comment: Proceedings version of plenary talk at Quark Nuclear Physics (QNP09)
September 2009, Beijing; matches published versio
Some aspects of mathematical and chemical modeling of complex chemical processes
Some theoretical questions involved in the mathematical modeling of the kinetics of complex chemical process are discussed. The analysis is carried out for the homogeneous oxidation of ethylbenzene in the liquid phase. Particular attention is given to the determination of the general characteristics of chemical systems from an analysis of mathematical models developed on the basis of linear algebra
Embodied Empiricism
This is the introduction to a collection of essays on 'embodied empiricism' in early modern philosophy and the life sciences - papers on Harvey, Glisson, Locke, Hume, Bonnet, Lamarck, on anatomy and physiology, on medicine and natural history, etc
The Lower Estimate for Bernstein Operator
MSC 2010: 41A10, 41A15, 41A25, 41A36For functions belonging to the classes C2[0; 1] and C3[0; 1], we establish the lower estimate with an explicit constant in approximation by Bernstein polynomials in terms of the second order Ditzian-Totik modulus of smoothness. Several applications to some concrete examples of functions are presented
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