U.S.-Bulgarian Cooperative Research: Metastable States of Exotic Helium Atoms and Delayed Annihilation of Antiprotons in Helium

这项美国-保加利亚合作研究奖将研究“外来氦原子的亚稳态和氦中反质子的延迟湮灭”。主要研究人员是特拉华大学的Krzysztof Szalewicz博士和保加利亚科学院核研究与核能研究所的Dimitre D. Bakalov博士。该项目的目的是为反质子氦的亚稳态和反质子氦的延迟湮灭现象提供高精度的从头算量子力学描述。该项目将为氦中的负介子或反质子停止时形成的少体束缚系统的能级提供精确的理论值，以及这些能级之间各种跃迁（俄歇、辐射和激光刺激）的速率。用变分方法计算类氦原子的介子和反质子的库仑能级，相对精度为10的-7次方。相对论和量子电动力学修正——包括精细和超精细分裂——将在微扰理论的一阶中进行评估。在强度高达10 ^ 4高斯的外均匀磁场中，还将评估能级的塞曼分裂。最后，对分子簇的影响进行了评价。这项工作应该能回答当前关于反物质的非常重要的问题，如果没有这次合作，这些问题是不可能完成的。这项在物理和天文学方面的研究实现了将美国和保加利亚的顶尖专家聚集在一起的计划目标，在平等、互惠和互利的基础上，在相互感兴趣和能力强的领域结合互补的努力和能力。* * * ? ?

INT-96 Szalewicz This U.S.-Bulgaria Cooperative Research award will study "Metastable States of Exotic Helium Atoms and Delayed Annihilation of Antiprotons in Helium." The principal researchers are Dr. Krzysztof Szalewicz of the University of Delaware and Dr. Dimitre D. Bakalov of the Institute for Nuclear Research and Nuclear Energy of the Bulgarian Academy of Sciences. The purpose of the project is to provide a high accuracy of ab initio quantum mechanical description of the metastable states of antiprotonic helium and of the phenomenon of delayed annihilation of antiprotons in helium. The project will give precise theoretical values for the energy levels of the few-body bound systems that are formed when stopping negative muons or antiprotons in helium, as well as the rates of various transitions (Auger, radiative, and laser stimulated) between these levels. The Coulomb energy levels of the muonic and antiprotonic helium-like atom will be calculated with a relative accuracy of 10 to the -7 using variational methods. The relativistic and quantum electrodynamics corrections -- including the fine and hyperfine splitting -- will be evaluated in the first order of perturbation theory. The Zeeman splitting of the levels in external homogeneous magnetic field of intensity up to 10 to the 4th Gauss will also be evaluated. Finally, the effect of molecular clusters will be estimated. This work should answer very important current questions about antimatter which could not be accomplished without this collaboration. This research in physics and astronomy fulfills the program objectives of bringing together leading experts in the U.S. and Bulgaria to combine complementary efforts and capabilities in areas of strong mutual interest and competence on the basis of equality, reciprocity, and mutuality of benefit. *** ??