Theoretical study of antiparticle collisions and exotic-atom formation

反粒子碰撞和奇异原子形成的理论研究

• 批准号: 07640523
• 负责人: TOSHIMA Nobuyuki
• 金额: $ 1.54万
• 依托单位: University of Tsukuba
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1995
• 资助国家: 日本
• 起止时间: 1995 至 1997
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07640523/
• 关键词: positron; positronium; antiproton; muon; hyperspherical; resonance; 反陽子ヘリウム; ミューオン触媒核融合; 超球座標

(1) Positron scattering by atoms was studied by means of a large-scale hyperspherical close-coupling method. For the helium atom target we employ a mdel potential which reproduces the ionizaiton potential very accurately on the basis of the quasi single-electron atom approximaiton. All the adiabatic channel functions are coupled fully that are associated with the helium atomic states with n=1-4 and positronium states with n=1-5 in the separated -atom limit. The obtained formation cross sections agree well with the measured values and the present results are the bast among available theoretical values so far. In the case of electron scattering by positronium, hyperfine-structure transitions are studied including the spin-spin interactions explicitly. We also studied Feshbach-type resonances of the positronim negative-ion and tabulated systematically the energy shifts and widths in a wide energy region.(2) Formation of antiprotonic helium was studied in the collisions of antiproton with … More helium atoms and helium ions using a large-scale impact-parameter close-coupling method based on the pseudo state expansion. Highly excited states around n=38 are calculated accurately developing a new method for the decomposition of angular parts of wave functions. The energy eigenvalues and the life times of Auger decays agree excellently with measurements. The antiproton trapping in the first stage is analyzed representing ionization channles in terms of discretized pseudo continuum states. Proton-impact scattering was also calculated ststematically for comparison.(3) Muon transfer between hydrogen isotopes was studied in connection with the muon-catalyzed fusion reseach. The transfer cross sections from excited states are found to be larger than that from the ground state by several hundreds times. This is caused by the long-range interaction induced by the large dipole moment of the degenerate excited states. Feshbach-type resonaces are found and the cross sections are influenced considerably. Less

(1)用大尺度超球密耦合方法研究了正电子与原子的散射。对于氦原子靶，我们采用了一个模型势，该势在准单电子原子近似的基础上非常准确地再现了电离势。在分离原子极限下，与n=1-4的氦原子态和n=1-5的正电子偶素态有关的绝热通道函数都是完全耦合的。计算结果与实测值吻合较好，是目前理论计算结果中最好的。在电子被正电子偶素散射的情况下，研究了包括自旋-自旋相互作用在内的超精细结构跃迁。我们还研究了正负离子的Feshbach型共振，并系统地列出了宽能区的能移和宽度。(2)研究了反质子与氦原子碰撞中反质子氦的形成 ...更多信息 采用基于赝态展开的大尺度碰撞参数紧耦合方法对氦原子和氦离子进行了数值模拟。精确计算了n=38附近的高激发态，为波函数角部分的分解提供了一种新的方法。俄歇衰变的能量本征值和寿命与测量结果吻合得很好。第一阶段的反质子捕获分析代表电离通道的离散伪连续态。为了比较，还统计计算了质子碰撞散射。(3)在μ子催化聚变研究中，研究了氢同位素之间的μ子转移。从激发态的转移截面比从基态的转移截面大几百倍。这是由简并激发态的大偶极矩引起的长程相互作用引起的。Feshbach型共振被发现和截面的影响相当大。少

项目成果

Y.D.Wang,N.Toshima C.D.Lin: "One- and Two-electron prcesses in colllisions oy He with 10-500KeV/amu Be ^<q+>(q=2-4)and B^<q+>(q=2-5)Ions" Physica Scripta. T62-1. 63-68 (1996)

Y.D.Wang、N.Toshima C.D.Lin：“He 与 10-500KeV/amu Be ^<q >(q=2-4) 和 B^<q >(q=2-) 碰撞中的一电子和二电子过程

A.Igarashi,N.Toshima T.Shirai: "Hyperspehricl coupled-cahnnel calculations of positronium formation in low-energy positron-helium collisions" Physical Review A. 54-6. 5004-5009 (1996)

A.Igarashi,N.Toshima T.Shirai：“低能正电子-氦碰撞中正电子形成的超球耦合通道计算”物理评论 A. 54-6。

N.Toshima: "On the instability of excitation and capture cross sections in the two-center AO close-coupling calculations" J.Phys. B30. L131-L136 (1997)

N.Toshima：“关于两中心 AO 紧耦合计算中激发和捕获截面的不稳定性”J.Phys。

M. F. V. Lundsgaad, Z. Chen, C. D. Lin and N.Toshima: "Electron capture from circular Rydberg atoms" Physical Review A. 31. 1347-1350 (1995)

M. F. V. Lundsgaad、Z. Chen、C. D. Lin 和 N.Toshima：“从圆形里德伯原子中捕获电子”物理评论 A. 31. 1347-1350 (1995)