手征夸克模型和手征幺正理论分别在奇特强子态和共振态及感兴趣介子的各种衰变分子比等相关物理问题中的应用

The exploration of exotic states and resonances , which are closely related with the recent experimental data from the large research facilities, is theoretically important and meaningful. 1) Recent WASA-at-COSY Collaboration claimed the existence of a d* exotic state, since its mass is above the threshold of ΔNπ channel, while its width is much smaller than the decay width of Δ, it is surely a very interesting exotic state involving new physical mechanisms, so it is obviously worthwhile investigating. Because the short-range interaction mechanism may have different effects on the multiquark exotic state, the chiral su(3) quark model and the extended chiral su(3) quark model will be utilized. Both models meet the requirements of the QCD chiral symmetry, but the short range mechanisms are totally different, one is from one-gluon-exchange and antother from vector meson exchange. We will investigate the possible existence of some interesting multiquark states, analyzing the effects from different short range mechanisms, hidden color channel and the mixing of scalar meson. The study of exotic state may open a door to new physical phenomena. 2) Many new resonance states and new decay branching ratios of mesons with charm quark and bottom are given by experimental groups. We will be in close connection with the large research facilities of BES, LHCb, MAINZ, ELSA, JLab, COSY, ... where experimental work is currently done. We will use the chiral unitary theory, which has successfully described many hadron resonance states confirmed experimentally, to further investigate and predict various new resonances. The nature of the resonances, the different decay (hadronic, weak, radiative) branching ratios of mesons with charm quark and bottom will be investigated and predicted by using the chiral unitary approach, testing the idea that these resonances are dynamically generated from the interaction of pairs of pseudoscalar mesons or pairs of vector mesons or meson-baryon. All these studies will be helpful in testing the theoretical models, understanding the nature of interaction. It may provide reasonable and possible guidance for future experiments.

紧密结合目前大科学装置上的实验进行相关的理论探索是重要且极有意义的。1) 最近WASA实验证实了d*奇特态的存在，其质量在ΔNπ阈之下且衰变宽度很窄，无疑其结构涉及新的物理机制，值得深入研究。由于短程相互作用机制对这种多夸克奇特态产生不同影响，本项目将利用满足QCD手征对称性要求的具有不同短程作用机制的两个模型即手征SU(3)夸克模型和扩展手征SU(3)夸克模型并考虑隐色道及标量介子混合角等因素来深入研究其他多夸克态存在可能性；2) 最近BES, MAINZ, ELSA , JLab, COSY, LHCb等很多实验组发现了一些新共振态和某些带粲和底夸克的感兴趣介子的弱衰变和强子与辐射衰变分支比实验数据。本项目将紧密结合这些最新的实验结果，利用手征幺正理论来研究和预言这些新共振态性质。这些工作将有助于检验模型理论，深入认识相互作用的本质，并为实验上新粒子寻找提供可能的合理依据和指导。

紧密联系国际上目前运行及未来拟建大科学装置上实验，开展了多夸克奇特态和强子共振态的理论探索。一方面，多夸克奇特态是一类全新物质结构，其是否存在，无疑是检验相互作用基本理论的重要场所。我们在满足QCD手征对称性要求的手征SU(3)夸克模型下，挑战了单个重子为色单态这一传统观念，探索了两个色八重态重子构成隐色道的耦合效应对双重子这一多夸克态结构的影响。找到一种新方法计算隐色道相互作用矩阵元，从而避免了复杂的群论计算。然后通过动力学计算，预言了非奇异d*镜像核的结构并进一步拓展到带奇异数系统，研究发现隐色道耦合效应对多夸克态形成非常重要。另一方面，在手征幺正理论下没有任何可调参数，在含粲和底夸克的介子弱衰变过程中检验共振态的分子性质，还研究了激发态的强子衰变和辐射衰变分支比问题。从理论上挑战实验声称1420MeV峰是新轴矢量共振态，通过三角奇异衰变机制完美解释了实验悬而未决的问题，从而开辟一个新视角去重新检验PDG新共振态性质；新探索性地研究含粲重子四体衰变过程和同位旋破缺模式；提出一种新颖代数方法研究含粲和底夸克介子半轻子衰变，建立了简洁的衰变振幅解析式，在没有任何可调参数下，预言了所有反应衰变分支比，探讨了螺旋度问题和超出标准模型新物理。对不同G宇称和衰变末态建立了衰变振幅解析式，研究了极化问题。 在tau衰变中开辟一个新方向检验共振态的分子性质，通过G宇称筛选不同反应，预言衰变分支比均在实验可测的范围内。这些工作会有助于检验模型理论，加深对相互作用本质的认识，并为实验提供可能的合理依据和指导。