441 research outputs found
ppK- bound states from Skyrmions
The bound kaon approach to the strangeness in the Skyrme model is applied to
investigating the possibility of deeply bound states. We describe the
system as two-Skyrmion around which a kaon field fluctuates. Each
Skyrmion is rotated in the space of SU(2) collective coordinate. The rotational
motions are quantized to be projected onto the spin-singlet proton-proton
state. We derive the equation of motion for the kaon in the background field of
two Skyrmions at fixed positions. From the numerical solution of the equation
of motion, it is found that the energy of can be considerably small, and
that the distribution of shows molecular nature of the system.
For this deep binding, the Wess-Zumino-Witten term plays an important role. The
total energy of the system is estimated in the Born-Oppenheimer
approximation. The binding energy of the state is MeV.
The mean square radius of the subsystem is
fm.Comment: Oct 2007, 15 pages, 8 figures; added references, corrected typo
Kaonic nuclei studied based on a new framework of Antisymmetric Molecular Dynamics
We have developed a new framework of Antisymmetrized Molecular Dynamics
(AMD), to adequately treat the I=0 \={K}N interaction, which is essential to
study kaonic nuclei. The improved points are 1) pK/n\={K} mixing and 2)
total spin and isospin projections. These improvements enable us to investigate
various kaonic nuclei (ppnK, pppK, pppnK, BeK and
BK) systematically. We have found that they are deeply bound and
extremely dense with a variety of shapes.Comment: 10 pages, 5 figure
A search for deeply bound kaonic nuclear states
We have measured proton and neutron energy spectra by stopping negative kaons
on liquid helium4. Two distinct peak structures were found on both spectra,
which were assigned to the formation of new kinds of strange stribaryons. In
this paper, we summarize both results.Comment: 7 pages, 3 figures, HYP2003 conference proceeding
Antigen p57/Kip2 as a potential negative regulator of human astrocytoma growth
This study was performed to determine the relationship between p57/Kip2 and the growth of human astrocytomas. Immunohistochemical staining for p57/Kip2, p53, p16, and Ki67 antigen was performed on paraffin-embedded tissue specimens obtained from 36 patients with astrocytoma. Expression of p57/Kip2, p53, p16, and Ki67 antigen was generally increased in association with the astrocytoma tumor grade. Expression of p16 was higher in patients whose tumors express p57/Kip2 in greater than 10% of tumor cells (p < 0.05). Expression of p53 also tended to be higher, but not to a statistically significant extent, in patients whose tumors express p57/Kip2 in greater than 10% of tumor cells. These findings suggest that p57/Kip2 inhibits the growth of human astrocytomas, and may function in parallel with p16 and p53. However, p57/Kip2 is, by itself, insufficient to arrest the cellular proliferation of human astrocytomas.ArticleJOURNAL OF CLINICAL NEUROSCIENCE. 16(12):1615-1618 (2009)journal articl
CFD analysis of the fluidised bed hydrodynamic behaviour inside an isothermal gasifier with different perforated plate distributors
The hydrodynamic behaviour of gas-solid mixtures inside Bed Fluidised Beds (BFB) gasifiers has a major impact on the gasification process due to particles - gas and particle - particle contact mechanisms. The Discrete Phase Model DPM with Multiphase Particle-in-Cell method MPPIC was used as a CFD approach to study the hydrodynamic behaviour of an 800 height x 83 mm φ prototype fluidised bed gasifier with 4 different perforated plate distributors. In terms of bubble forming, pressure drop and superficial velocity, the type D distributor, i.e. triangular, had the best performance among the other types and in turn better bed height and bed movement, thus allowing best fluidisation performance as a consequence of better flow distribution
New effective nuclear forces with a finite-range three-body term and their application to AMD+GCM calculations
We propose new effective inter-nucleon forces with a finite-range three-body
operator. The proposed forces are suitable for describing the nuclear structure
properties over a wide mass number region, including the saturation point of
nuclear matter. The forces are applied to microscopic calculations of
() nuclei and O isotopes with a method of antisymmetrized molecular
dynamics. We present the characteristics of the forces and discuss the
importance of the finite-range three-body term.Comment: 15 pages, 11 figures, submitted to Phys.Rev.
New Way to Produce Dense Double-Antikaonic Dibaryon System, \bar{K}\bar{K} NN, through Lambda(1405)-Doorway Sticking in p+p Collisions
A recent successful observation of a dense and deeply bound \bar{K} nuclear
system, K^-pp, in the p + p \rightarrow K^+ + K^-pp reaction in a DISTO
experiment indicates that the double-\bar{K} dibaryon, K^-K^-pp, which was
predicted to be a dense nuclear system, can also be formed in p+p collisions.
We find theoretically that the K^- -K^- repulsion plays no significant role in
reducing the density and binding energy of K^-K^-pp and that, when two
\Lambda(1405) resonances are produced simultaneously in a short-range p+p
collision, they act as doorways to copious formation of K^-K^-pp, if and only
if K^-K^-pp is a dense object, as predicted.Comment: 8 pages, 9 figures, Accepted Apr. 19, 201
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