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Spectra of Strangeness Production Reactions and Baryon Excited States in Nuclear Medium

核介质中奇异产生反应和重子激发态的光谱

基本信息

批准号：
15540284
负责人：
KOHNO Michio
金额：
$ 0.7万
依托单位：
Kyushu Dental College
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

项目摘要

The study of the Σ-N interaction is essential to understanding the physics of octet baryons. However, in contrast to the A, the Σ single-particle (s.p) potential in nuclear media, which reflects basic properties of the Σ-N interaction, has not been established, because experimental information is scare. Even its sign has not been established Recently, (π^-,K^+) spectra corresponding to Σ formation were measured employing various nuclei targets at KEK with better precision, using 1.2 GeV/c π^-. Based on these spectra, it was found that the potential deduced from their DWIA analysis is strongly repulsive, as large as 100 MeV. Considering the importance of understanding the Σ-N interaction for our description of the whole octet baryon-baryon interactions, it is desirable to carry out an independent analysis of the KEK experiments. In this study, I develop a semiclassical method for the DWIA approach and apply it to (π^-,K^+) inclusive spectra. The expression of the double differential cross section consists of the incoming pion distorted wave function, the outgoing kaon distorted wave function and the undetected hyperon distorted wave function at each collision point, where conservation of the classical local momentum holds. The application of this model to the (π^-,K^+) inclusive spectrum obtained with 28Si targets at KEK has shown that the shape and magnitude of the spectrum is satisfactorily reproduced by a repulsive Σ-nucleus potential of the order of 30-50 MeV. This magnitude, in turn, constrains the Σ-N potential model and thereby improve our understanding of the interactions between complete octet baryons. The present framework can be easily applied to describe other inclusive spectra, such as (K,π),(π,η), (γ,K), and soon. It is also straightforward to consider multistep contributions.

研究八重态重子与N原子的相互作用对理解八重态重子物理是必不可少的.然而，与A相反，由于实验资料的缺乏，核介质中反映核-N相互作用基本性质的单粒子势（s.p）还没有建立起来。最近，在KEK用1.2 GeV/c π^-，用各种不同的核靶，以更高的精度测量了对应于质子形成的（π^-，K^+）谱。基于这些光谱，人们发现，从他们的DWIA分析推导出的潜力是强烈的排斥，高达100 MeV。考虑到理解重子-重子相互作用对我们描述整个八重态重子-重子相互作用的重要性，对KEK实验进行独立的分析是必要的。在这项研究中，我开发了一个半经典的DWIA方法，并将其应用于（π^-，K^+）包含光谱。双微分截面的表达式由入射的π扭曲波函数、出射的K介子扭曲波函数和未探测到的超子扭曲波函数组成，在每个碰撞点处经典局域动量守恒成立。将该模型应用于在KEK下用28 Si靶获得的包含（π^-，K^+）的能谱表明，能谱的形状和大小可以用30-50 MeV量级的排斥性π-核势令人满意地再现。这个量级反过来又限制了N-N势模型，从而提高了我们对完整八重态重子之间相互作用的理解。该框架可以很容易地应用于描述其他包含谱，如（K，π），（π，η），（γ，K）等。考虑多步贡献也很简单。