粲偶素和类粲偶素衰变行为的唯象学研究

The decay behaviors of charmonia and charmonium-like states closely connect to the perturbative and unperturbative properties of QCD (Quantum Chromodynamics), researches on these decay behaviors can deepen our understanding of QCD. Many new decay modes of charmonia and abundant charmonium-like states have been observed in recent years. These new experimental measurements are great challenges of present theories and phenomenological models. Discrepancies between experimental measurements and investigations based on perturbative QCD appear in many new decay modes of charmonia. The researches on the decay behaviors of charmonia based on measurements from BESIII as well as other experimental results in the world will help us to unveil the new mechanisms in charmonia decay and find better phenomenological models to describe the unperturbative property of QCD. The discoveries of charmonium-like states provide good opportunities for searching high excited charmonia and QCD permitted exotic states. However, the properties of these charmonium-like states are still unclear at present, and it is necessary and interesting to perform further researches on these states. In present program, we will study the decay behaviors of charmonium-like states from three aspects, which are high excited charmonia, molecular states and special mechanism productions. These investigations will enlarge our knowledge of charmonium-like states and help us to find the nature of these states. The researches can also provide important information for further experimental detections of charmonia and charmonium-like states.

粲偶素和类粲偶素的衰变行为与微扰QCD和非微扰QCD有密切关系，研究这些衰变行为能够加深我们对QCD的理解和认识。近年来，实验上观测到粲偶素的许多新衰变模式和众多类粲偶素，对现有的理论和唯象模型提出了挑战。粲偶素的许多新衰变模式与微扰QCD的计算有较大的差异。我们将基于实验观测，特别是高能所BESIII上的相关实验，研究粲偶素的衰变行为，探索新的机制以更好地描述QCD的非微扰效应。类粲偶素的发现为寻找高激发态粲偶素和QCD允许的奇特态提供了非常好的机遇。但是到目前为止，人们对许多类粲偶素的本质还不清楚，对类粲偶素性质的进一步研究是非常有意义的。本项目将从粲偶素、分子态、特殊机制产生等方面对类粲偶素的衰变行为开展研究，加深我们对类粲偶素的认识并进一步确定其本质。这些研究也将为实验上进一步探测粲偶素和类粲偶素提供理论支持。

粲偶素和类粲偶素的研究是最近十多年来强子物理的研究热点和前沿。本项目通过不同的角度对这些新强子态的谱学和衰变行为进行了深入的研究。对于一些近阈的新强子态，我们在分子态的框架下对他们的谱学和衰变行为进行了研究。我们通过介子交换模型计算强子对形成束缚态的可能性，然后利用有效拉氏量方法计算这些分子态的衰变行为，并与相关的实验观测比较来进一步评估该新强子态解释为分子态的可能性。对于一些可能的介子高激发态，我们通过与组分夸克模型计算得到的质量比较确定其可能在介子谱中的位置，然后利用3P0模型计算其强衰变行为，并与实验观测比较进一步确定其性质。我们还对一些类粲偶素提出了非共振态解释，认为这些类粲偶素并不是真正的强子态，而是由于某些干涉造成的。我们这些研究一方面对目前实验观测提出了解释，另一方面预言一些新的现象，为实验上进一步观测新强子态提供理论支持。