Pentaquark baryon in anisotropic lattice QCD

The pentaquark (5Q) baryon is studied in anisotropic quenched lattice QCD with renormalized anisotropy a_s/a_t = 4 for a high-precision mass measurement. The standard Wilson action at β= 5.75 and the O (a) improved Wilson quark action with k = 0.1210(0.0010)0.1240 are employed on a 12^3 × 96 lattice. Contribution of excited states is suppressed by using a smeared source. We investigate both the positive- and negative-parity 5Q baryons with I = 0 and spin J = 1/2 using a non-NK-type interpolating field. After chiral extrapolation, the lowest positive-parity state is found to have a mass, m_ = 2.25 GeV, which is much heavier than the experimentally observed Θ^+ (1540). The lowest negative-parity 5Q state appears at m_ = 1.75 GeV, which is near the s-wave NK threshold. To distinguish spatially-localized 5Q resonances from NK-scattering states, we propose a new general method imposing a ‘‘Hybrid Boundary Condition (HBC),’’ where the NK threshold is artificially raised without affecting compact five-quark states. The study using the HBC method shows that the negative-parity state observed on the lattice is not a compact 5Q state but an s-wave NK-scattering state.journal articl

68年運動 : ドイツ・西ヨーロッパ・アメリカ [翻訳]

application/pdfArticle言語と文化 .13 ,p.37-42departmental bulletin pape

Quasi-one-dimensional electronic structure of (DMET)_2CuCl_2

The anisotropic transfer integrals characterizing the quasi-one-dimensional (Q1D) electronic structure are determined experimentally for the new organic superconductor (DMET)_2CuCl_2 by angle-dependent magnetoresistance and polarized reflectance measurements. Lebed resonances and third angle effect are observed in the angle-dependent magnetoresistance; the latter gives the ratio of the inter- and intra-stack transfer integrals as t_{a'} / t_b=0.1. From the anisotropy of the plasma frequency found in the polarized reflectance spectra, the intraand inter-stack transfer integrals are deduced as t_b=0.28 eV and t_{a'}=0.028 eV, respectively, in good agreement with the results of the third angle effect. The observed anisotropy of the transfer integrals is the same as those for the Q1D TMTSF salts, which is consistent with the appearance of the field-induced spin-density-wave states at magnetic fields similar to those of the Q1D TMTSF salts.journal articl

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Controlled Crystalline Structure and Surface Stability of Cobalt Nanocrystals

The synthesis of monodispersed 10 nm cobalt nanocrystals with controlled crystal morphology and investigation of the surface stability of these nanocrystals are described. Depending on the surfactants used, single crystalline or multiple grain nanocrystals can be reproducibly produced. The relative surface stability of these nanocrystals is analyzed using the temperature dependences of the dc magnetic susceptibility. The novel method, which allows sensitive monitoring of the surface stability, is based on the observation that, with particle oxidation, an anomalous peak appears at 8 K in zero-field-cooled magnetization measurements. It is found that the surfactant protective layer is more important for long-term stability at room temperature, while the high-temperature oxidation rate is controlled by the crystal morphology of the nanoparticles

A genome-wide linkage scan for body mass index on Framingham Heart Study families-0

<p><b>Copyright information:</b></p><p>Taken from "A genome-wide linkage scan for body mass index on Framingham Heart Study families"</p><p>http://www.biomedcentral.com/1471-2156/4/s1/S97</p><p>BMC Genetics 2003;4(Suppl 1):S97-S97.</p><p>Published online 31 Dec 2003</p><p>PMCID:PMC1866538.</p><p></p>me 3, (C) chromosome 11, and (D) chromosome

ソーラードライヤーシステムに関する基礎的研究 (第2報) : 籾乾燥のための太陽熱コレクターシミュレーション

application/pdf(1)The flat plate collector was produced for grain drying application. The performance tests were conducted with three type of air flow using various air flow rates. 1) Collector efficiency increases as air flow rates increase. Among three types of air flow, the order of efficiency is first, the reversed flow type, follwed by two-way flow type and the upper flow type. 2) The air temperature rise decrease as air flow rates increase. Especially in the reversed flow type, air temperature rise beyond 15℃ is attained when he average solar radiation is 1.2 cal/cm²min. Thus, the results indicate that the reversed flow type offers the best performance of the three types of air flow. (2) The mathematical model of the solar collector was developed as one part of solar grain drying simulation. Simulation results for the temperatures of the absorbing plate,the cover and the air showed reasonable agreement with the experimental data. It was demonstrated that this model was reasonably valid for simulation studies of rise drying. (3) Then, the simulation model was used to predict collector performance. The results were as follows: 1)Temperatures of the absorbing plate rise with an increase in the air flow rates and with a decrease in the collector area. 2) Air temperature is raised as air flow rates decrease and the collector area increases. 3) Collector efficiency increases with an increase in air flow rates. These conclusions agree well with the experimental results, showing that this model can be also used for the prediction of collector performance. (4) Simulation results showed the expression of the relationship between air flow rate and the energy collected to the each collection area. Thus, if air flow rate and collection area are assumed, energy collection can be calculated. Then, the relationship of energy collected and the collection area to air flow rates are shown in eqs.(21),(22). These can be used to predict the collection area when solar radiation is received in the drying season Aug.-Oct..departmental bulletin pape