Spectral Analysis of Excited Nucleons in Lattice QCD with Maximum Entropy Method

We study the mass spectra of excited baryons with the use of the lattice QCD simulations. We focus our attention on the problem of the level ordering between the positive-parity excited state N'(1440) (the Roper resonance) and the negative-parity excited state N^*(1535). Nearly perfect parity projection is accomplished by combining the quark propagators with periodic and anti-periodic boundary conditions in the temporal direction. Then we extract the spectral functions from the lattice data by utilizing the maximum entropy method. We observe that the masses of the N' and N^* states are close for wide range of the quark masses (M_pi=0.61-1.22 GeV), which is in contrast to the phenomenological prediction of the quark models. The role of the Wilson doublers in the baryonic spectral functions is also studied.Comment: 15 pages, 5 figures included, typos corrected, and references adde

テレメーター法による長距離走トレーニング強度の研究

In order to predict the training intensity in long distance running, the percent of maximum oxygen uptake in daily training was estimated from heart rate response which was measured by means of telemetering. Four male distance runners participated in this experiment. These results were summarized as follows ; 1) In order to clarify the difference between directly measured VO_2 max and that predicted from heart rate, oxygen uptake and heart rate were measured simultaneously in treadmill running which produced the same pattern as the daily training program. The differences of % of VO_2 max predicted from heart rate and measured directly were about 10% 2) The training intensity was evaluated by % of VO_2max which was predicted from the variation of heart rate in long distance running. The training intensity in 6, 000m continuous running was equivalent to 70～85% of VO_2max. In intermittent run ning, which consisted of 1, 000m run seven times and 3, 000m run five times, it indicated 90～100% of VO_2max. 3) There were rectilinear relationships between running speed and percent of maximum oxygen uptake. The regretion equation was different for each athlete. At a given running speed the large difference of % of VO_2max btween individuals was observed

Fatigue Damage Evaluation by Diffraction Contrast Tomography Using Ultra-Bright Synchrotron Radiation

A three-dimensional grain mapping technique for polycrystalline materials, called X-ray diffraction contrast tomography (DCT), was developed at SPring-8, which is the brightest synchrotron radiation facility in Japan. The developed technique was applied to an austenitic stainless steel. The shape and location of grains could be determined by DCT using the apparatus in a beam line of SPring-8. To evaluate the dislocation structure in fatigue, the total misorientation of individual grains was measured by DCT. The average value of the total misorientation over one sample was increased with the number of cycles. In a grain, the change of the total misorientation was largest for the primary slip plane. The maximum change of the total misorientation in fatigue was larger for planes with larger Schmid factor, and the first fatigue crack initiation was occurred in a grain, which had the greatest change of the total misorientation