高激发开粲介子的产生和衰变研究

In recent years, many new resonances as suspect open-charmed mesons were found in experiments. Before determining the classification of these new particles, it is necessary to conduct a thorough study about the spectrum of open-charmed mesons. This project attempts to carry out the research on the properties of production and decay processes of highly excited open-charmed mesons, with D_{sJ}(3040)^+ as the typical one, via the improved mothed of Bethe-Salpeter equation based on the potential model, in the interpretation of heavy-light-quark bound state. The main topics to expand in two ways: on one hand, the widths of the B or B_s meson’s weak decays and the production rates of the highly excited open-charmed mesons birthing from them will be studied; on the other hand, all the possible OZI-allowed strong decay widths of the highly excited open-charmed mesons above the threshold are going to be investigated and used to estimate the total width of the particle. Due to the method of good relativistic kept in both the wave functions and the decay amplitudes adopted，the results of this subject should be more precise compared with those of the previous approaches of non-relativistic models. Here we attempt to solve the mixing issue of 1^+ state, and apply it efficiently to the processes which highly excited open-charmed mesons are involved in. This program would help people understand the meson spectrum of open-charmed states in depth, and provide advice or guidance to the further research on open-charmed mesons both theoretically and experimentally.

近年来实验上发现了许多疑似开粲介子的新共振态。在判定这些新粒子的类别归属之前，有必要对传统开粲介子谱进行彻底研究。本项目试图通过基于势模型改进的Bethe-Salpeter方程方法，按照重-轻夸克束缚态诠释对以D_{sJ}(3040)^+为代表的高激发开粲介子产生和衰变过程进行研究。课题主要沿两个方向展开：一是研究B或B_s介子弱衰变的衰变宽度与高激发开粲态介子在其中的产生率，二是研究质量处于阈上的高激发开粲介子可能发生的OZI允许强衰变的各道分宽度并用以估计该粒子总宽度。由于所采用的方法中无论波函数还是衰变振幅都保持了良好的相对论性，本课题的结论与以往采用非相对论模型的处理方式相比应更为准确。我们还将解决1^+态的混合态问题，并将其有效应用于对高激发开粲介子参与的过程研究中。本项目会帮助人们深入地理解开粲态介子谱，为理论和实验中对开粲介子的进一步研究提供建议或指导。

本课题针对高激发态开粲介子，利用基于势模型改进的相对论性Bethe-Salpeter方法，结合曼德尔斯塔姆机制对衰变矩阵元进行处理，进而精确计算衰变宽度和分支比。该方法考虑了相对论修正项带来的贡献，允许更为细致地对于开粲介子的高激发态组成和谱系开展研究，从而加深和丰富对于粲介子弱衰变过程和非微扰QCD的理解。随着LHC的运行，含粲介子的数据积累也越来越丰富。$D_{sJ} (3040)^+$和$D_J(3000)^0$极有可能为$D_s(2P)$和$D(2P)$态，二者产生于实验上的$e^+e^-$相互作用和$D\pi$道。结果表明，$B_s$和$B$的半轻衰变是可供大量产生$D_{sJ} (3040)^+$和$D_J(3000)^0$的极好研究平台。呼吁对于高激发的$2P$态含粲介子感兴趣的实验组重点关注以上半轻衰变道的数据。