Basic Science Research by High Intensity Meson Beams

在欧洲核子研究中心进行了亚稳态反质子原子的激光共振光谱实验。当一个能量与从亚稳态到短寿命态的跃迁相匹配的脉冲激光在反质子到达后被发射时，在反质子湮灭时间谱的延迟部分预计会出现一个尖锐的尖峰。我们使用了来自欧洲核子研究中心低能反质子环（LEAR）的200MeV/c的反质子束。我们在597.26nm的激光波长处发现了一个尖峰，这是由(n, iota) =(39,35)到（38,34）态的共振跃迁引起的。因此，我们已经确定了氦中反质子的亚稳态是由中性反质子氦原子的亚稳态引起的。关于寻找深束缚电子原子，我们准备了一个实验，将在GSI与德国的一个小组合作完成。在TRIUMF的介子设备上进行了各种实验。本项目的目的之一是获得对高Tc超导体的基本认识，特别是铜氧化物层结构的作用和氧对超导性的贡献。由于在TRIUMF的强负μ子通道是由UTMSL和TRIUMF合作建立的，负μ子自旋方法（mu^-SR）已被广泛应用于该主题。利用高质量的单晶，在LaSrCuO体系上获得了精确的顺磁位移，其随温度、掺杂剂浓度和相对于晶体轴的磁场方向的变化而变化。对负介子氧（mu^-O）的弛豫也进行了研究，以得到电子自旋的动力学方面。一个显著的成就是成功地分离了不同氧位点的mu^-O信号，这为氧的作用提供了线索。对于水，也可以得到mu^-O的化学状态。为了对金属氧化物中mu^-O的基本认识，对三维过渡金属氧化物中mu^-O的研究是必然的。对各种3d过渡金属氧化物进行了研究，特别是对MnO中顺磁位移的温度依赖性的精确测量揭示了有趣的局部磁有序。在毛伊岛举行的国际减灾会议上报告了其中一些成就。少

Experiments on laser resonance spectroscopy on metastable antiprotonic atoms were carried out at CERN. When a pulsed laser with an energy matched to a transition from a metastable state to a short lived state is fired after the arrival of an antiproton, a sharp spike is expected to appear on a delayed part of the antiproton annihilation time spectrum. We used the antiproton beam of 200MeV/c from the Low Energy Antiproton Ring (LEAR) of CERN.We discovered a sharp spike at a laser wave length of 597.26nm which was assigned to a resonance transition from the (n, iota) =(39, 35) to the (38, 34) state. Thus, we have established that the metastability of antiprotons in helium arises from the metastable states of the neutral antiprotonic helium atomcule.Regarding the search for deeply-bound pionic atoms we prepared an experiment to be done at GSI in collaboration with a group in Germany.Various experiments were carried out at the TRIUMF muon facilities. One of the purposes of this project is … More to obtain the basic understanding of high Tc superconductors, especially the role of the copper-oxide layer structure and the contribution of oxygen to the superconductivity. Since the intense negative muon channel at TRIUMF was built by the collaboration between UTMSL and TRIUMF, the negative muon spin rotation method (mu^-SR) has been intensively applied to this subject.By using a single crystal of good quality, precise paramagnetic shift was obtained on the LaSrCuO system with its dependence on temperature, on dopant concentration and on magnetic field direction with respect to the crystal axis. The relaxation of negative muonic oxygen (mu^-O) has also been studied to get the dynamic aspect of the electron spin.One remarkable achievement is the success of the separation of mu^-O signals for different oxygen sites, which gives the hints for the role of oxygen.Also for water knowledge of chemical state of mu^-O can be obtained. For the basic understanding of mu^-O in metal oxides, the study of mu^-O in 3d transition metal oxides is inevitable. The study is performed on various 3d-transition metal oxides, especially the precise measurement of temperature dependence of paramagnetic shift in MnO reveals an interesting local magnetic ordering.Some of these achievements were reported at the muSR international conference in Maui. Less