118907734
Separation of the variables in the solar neutrino problem.
122585803
Construction and properties of acrylic vessels in the RENO detector
Abstract The aim of the RENO (Reactor Experiment for Neutrino Oscillation) is to measure the smallest neutrino mixing angle, θ 13 . The RENO detector consists of four concentric cylindrical layers: the target, γ - catcher , buffer and veto. Acrylic is used for the target and γ - catcher vessels, both of which contain liquid scintillator. Acrylic was chosen because it has good transmittance in the wavelength range of 400 – 430 nm and also does not react with liquid-scintillating solvents. In order to reduce systematic uncertainties, the target volume should be identical to a level of less than 0.1% between the near and far detectors. Furthermore, the acrylic vessel should not have any leaks. In this paper, we investigate the optical properties, design and construction of the acrylic vessels used in the RENO detector.
121615298
Measurement of the refractive index of the LAB-based liquid scintillator and acrylic at RENO
In this paper, we describe the first measurement of the refractive index of the linear alkyl benzene (LAB)-based liquid scintillator and acrylic used at the Reactor Experiment for Neutrino Oscillation (RENO). The refractive index of a material is an important optical property and the prism spectrometer is the most common device for measuring the refractive index. Using the minimum deviation technique, which requires an exact measurement of the apex angle, we determined the refractive indices at six different wavelengths and then fitted them. We also compared the refractive index of the LAB-based liquid scintillator with the refractive indices of other liquid scintillator solvents commonly used in reactor neutrino experiments.
117078167
Real Time, Directional Measurement of BORON-8 Solar Neutrinos in the Kamiokande-II Detector and Search for Short-Time Variation
184667614
Current Status of RENO Experiment
122749310
RENO: Reactor experiment for neutrino oscillation at Yonggwang
The RENO experiment is under construction to measure the value of the smallest and unknown neutrino mixing angle θ13. The experiment will compare the measured fluxes of electron antineutrinos at two detectors located at 290 m and 1.4 km distances from the center of the Yonggwang nuclear reactors in Korea. It is planned to start data-taking in early 2010. An estimated systematic uncertainty associated with the measurement is less than 0.6%. With three years of data, the experiment will search for the mixing angle values of sin22θ13 down to 0.02.
14759979
Reddening Behaviors of Galaxies in the SDSS Photometric System
ABSTRACT. We analyze the behaviors of reddening vectors in the SDSS photometric system for galaxies of different morphologies, ages, and redshifts. As seen in other photometric systems, the dependence of reddening on the spectral energy distribution (SED) and the nonlinearity of reddening are likewise nonnegligible for the SDSS system if extinction is significant (1mag 1 mag ). These behaviors are most significant for the g g filter, which has the largest bandwidthtocentral-wavelength ratio among SDSS filters. The SDSS colors involving adjacent filters show greater SED dependence and nonlinearity. A procedure for calculating the correct amount of extinction from an observed color excess is provided. The relative extinctions between (i.e., the extinction law for) SDSS filters given by Schlegel etal., which were calculated with an older version of filter response functions, would underestimate the amount of extinction in most cases by 5% 5 % to 10% (maximum 20% 20 % ). We recommend A/A5500 A / A 5500 values...
118247985
N=5 three-algebras and 5-graded Lie superalgebras
We discuss a generalization of N=6 three-algebras to N=5 three-algebras in connection to anti-Lie triple systems and basic Lie superalgebras of type II. We then show that the structure constants defined in anti-Lie triple systems agree with those of N=5 superconformal theories in three dimensions.
16692832
Evaporation of Compact Young Clusters near the Galactic Center
We investigate the dynamical evolution of compact young clusters (CYCs) near the Galactic center (GC) using Fokker-Planck models. CYCs are very young (<5 Myr), compact (<1 pc), and only a few tens of parsecs away from the GC, while they appear to be as massive as the smallest Galactic globular clusters (~104 M?). A survey of cluster lifetimes for various initial mass functions, cluster masses, and Galactocentric radii is presented. Short relaxation times due to the compactness of CYCs and the strong tidal fields near the GC make clusters evaporate fairly quickly. Depending on cluster parameters, mass segregation may occur on a timescale shorter than the lifetimes of most massive stars, which accelerates the cluster's dynamical evolution even more. When the difference between the upper and lower mass boundaries of the initial mass function is large enough, strongly selective ejection of lighter stars makes massive stars dominate even in the outer regions of the cluster, so the dynamical evolution of those clusters is weakly dependent on the lower mass boundary. The mass bins for Fokker-Planck simulations were carefully chosen to properly account for a relatively small number of the most massive stars. We find that clusters with a mass 2 ? 104 M? evaporate in 10 Myr. Two CYCs observed near the GC?the Arches cluster (G0.121+0.17) and the Quintuplet cluster (AFGL 2004)?are interpreted in terms of the models; their central densities and apparent ages are consistent with the hypothesis that they represent successive stages of cluster evolution along a common track, with both undergoing rapid evaporation. A simple calculation based on the total masses in observed CYCs and the lifetimes obtained here indicates that the massive CYCs make up only a fraction of the star formation rate (SFR) in the inner bulge estimated from Lyman continuum photons and far-IR observations. This is consistent with the observation that many stars in the inner bulge form outside the large clusters.
122861815
Beam test of the CsI(Tl) calorimeter for the BELLE detector at the KEK-B factory
We studied the performance of a prototype electromagnetic calorimeter for the BELLE detector at the KEK proton synchrotron for an energy range of 0.25-3.5 GeV. The prototype consisted of an array of 6 x 5 CsI(Tl) crystals with 30 cm length (16.2 radiation lengths) and about 6 cm x 6 cm cross section. The scintillation light of each CsI(Tl) crystal was read out by two large-area PIN photodiodes and charge-sensitive preamplifiers attached at the rear face of the crystal. We measured the energy and position resolution for electrons and the e/pi separation for two sets of matrix configurations: one corresponded to the center and the other to the edge of the barrel calorimeter. The overall performance measured by the test proves that the prototype calorimeter is satisfactory for the use in the BELLE detector.
14620141
Evolution of Debris of a Tidally Disrupted Star by a Massive Black Hole: Development of a Hybrid Scheme of the SPH and TVD Methods
The evolution of the stellar debris after tidal disruption due to the super massive black hole's tidal force is difficult to solve numerically because of the large dynamical range of the problem. We developed an SPH (Smoothed Particle Hydrodynamics) - TVD (Total Variation Diminishing) hybrid code in which the SPH is used to cover a widely spread debris and the TVD is used to compute the stream collision more accurately. While the code in the present form is not sufficient to obtain desired resoultion, it could provide a useful tool in studying the aftermath of the stellar disruption by a massive black hole.