Quark recombination model for polarizations in inclusive hyperon productions at high energy

We investigate the transverse polarization of hyperons produced by the photon induced reactions using the quark recombination model. This model reproduces polarizations of hadrons produced by the hadron-hadron collisions and accounts for the origin of the empirical rule by DeGrand and Miettinen. We find significant polarizations in the hyperon photoproduction by applying this model to the \gamma N \ra \Lam $(\Sigma^{0}) + X$ reaction.Comment: Latex, 6 page with 6 figures, to be published in proceedings of APCTP Workshop on "Strangeness Nuclear Physics", Feb. 19-22, Seoul, Kore

Validation of 241Am Capture Cross Section through Integral Test Using Criticality Data of Light-water Moderated MOX Cores

AbstractIn the development of JENDL-4.0, the thermal and resonance capture cross section of 241Am was increased by about 8-9% to reduce the overestimation of criticality observed in the MOX-Fueled light-water-moderated cores using 241Am-rich plutonium-fuel.The revised data gives the better results of criticality prediction for those cores than that with JENDL-3.3. The Pu ageing problem was also investigated using the revised data. This problem is that the calculated k-effs for critical MOX cores with different experiment dates showed the tendency of increase with time. The change of k-eff in seven years was about 0.2%dk/k with JENDL-3.3 and it was reduced to about 0.1%dk/k with JENDL-4.0. These results show that the revision of 241Am capture cross section seemed to be successful, although there still remains the tendency of k-eff increase with time. On the other hand, the recent measurement of thermal and resonance capture cross section of 241Am indicates that the data of JENDL-3.3 should be increased by about 18%, that is about 8% greater than that of JENDL-4.0.In the present study, the possibility of further revision of 241Am capture cross section was studied through the integral test for Pu ageing problem by reflecting the recent experimental data. Three criticality data of a light-water moderated MOX core with different experiment date (7 years interval at maximum) have been analyzed with JENDL-3.3 and 4.0 libraries. In addition, the calculations with the number density of 241Am multiplied by 1.18 for JENDL-3.3 and by 1.08 for JENDL-4.0 were also conducted to simulate the increase of 241Am capture cross section suggested by the recent measurement. The results show that the increase tendency of k-eff as a function of time observed in the calculations with JENDL-4.0 is not found in those with modified 241Am number density. This means that the improvement of 241Am capture cross section will be achieved by employing the recent experimental data

Near-Infrared Spectroscopy of the Cool Brown Dwarf, SDSS 1624+00

Using the Subaru Telescope, we have obtained multiple near-infrared spectra of the cool brown dwarf, SDSS 1624+00, in search of spectral variability in an 80 minute time span. We have found the suspected variability of water vapor absorption throughout the observations, which requires confirmation by a longer time baseline. After coadding the spectra, we have obtained a high-quality spectrum covering 1.05 to 1.8 um. Three kinds of spectral indicators, the water vapor bands, methane band, and KI lines in J band, suggest that SDSS 1624+00 is warmer and dustier than Gl 229B.Comment: 6 figures, to appear in PAS