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Study of low energy ^^-KN interaction

低能^^-KN相互作用的研究

基本信息

批准号：
11440076
负责人：
IWASAKI Masahiko
金额：
$ 8.26万
依托单位：
TOKYO INSTITUTE OF TECHNOLOGY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2001
项目状态：
已结题

项目摘要

We have been studying the strong interaction between nucleon and K meson (kaon) by replacing an electron in the hydrogen atom with kaon, which has a strange quark. When, kaon stops in the gaseous hydrogen target, kaonic hydrogen atom is generated. The energy of the emitted x ray from the successive deexcitation gives energy shift and line width broadening from the electromagnetic value, especially for the transition to the ground. Therefore, the precise measurement of this X rays gives the most basic information of the ^^-KN interaction at the low energy limit. We have succeeded to observe the kaonic hydrogen 2p to 1s transition at KEK PS-E228 (KpX), and began the DAΦNE-DEAR experiment to deduce the isospin dependence of the interaction by detailed study both on K-d and K-p atom X rays observations.However, the way of the research is not necessarily smooth. The biggest problem is that the accelerator operation had been delayed substantially from the schedule away beyond the expectation. Moreover, we had been suffered by the huge background, which exceeded the expectation by 100 times more. On the other hand, this difficulty promoted a joint research with the theory with Akaishi et al. It is shown that the kaon may form a stable state inside the nuclei, based on the results i) our GSI experiment S218 revealed that the pi meson can exist inside the nuclei, and ii) our KpX result indicated strongly attractive nature between kaon and proton. If there exist deeply bound kaonic state inside nuclei, the purpose of this research program can be achieved more directly in more efficient way. By the present grant, we were able to start the search for the deeply-bound kaonic state at KEK (PS-E471).

我们一直在研究核子与K介子（kaon）之间的强相互作用，方法是用具有奇异夸克的kaon取代氢原子中的电子。当k介子停在气态氢靶时，生成k介子氢原子。连续去激发所发射的x射线的能量从电磁值产生能量移位和线宽展宽，特别是向地的过渡。因此，对这种X射线的精确测量给出了低能极限下^^-KN相互作用的最基本信息。我们在KEK PS-E228 （KpX）上成功地观察到了kaonic氢的2p到1s跃迁，并通过K-d和K-p原子X射线的详细研究，开始了DAΦNE-DEAR实验来推导相互作用的同位旋依赖。然而，研究的道路并不一定是一帆风顺的。最大的问题是，加速器的运行被大大推迟，远远超出了预期。而且，我们已经遭受了巨大的背景，超过预期的100倍。另一方面，这一困难促进了与Akaishi等人的理论联合研究。我们的GSI实验S218揭示了介子π介子可以存在于原子核内，KpX结果表明了介子与质子之间具有很强的吸引力，表明了介子可以在原子核内形成稳定的状态。如果原子核内存在深束缚态，则可以更直接、更有效地达到本研究计划的目的。在目前的资助下，我们能够开始在KEK （PS-E471）上寻找深束缚的kaonic态。