Novel Pentaquarks from Diquark-Triquark Model
Novel Pentaquarks from Diquark-Triquark Model
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发表时间：
2015-10
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通讯作者：
R. Zhu;C. Qiao
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作者：
R. Zhu;C. Qiao
我们用组成双夸克-三夸克模型来解释最近由LHCb合作发现的charmonon -五夸克态，即P_c(4380)$和P_c(4450)$。我们分析了三夸克的颜色吸引构型，并首次定义了五夸克态的非局域波函数，其中二夸克和三夸克都不是紧致的类点，而是具有非零大小。建立了基于自旋轨道相互作用的有效重夸克-三夸克哈密顿量。然后得到$\frac{5}{2}^+$和$\frac{3}{2}^-$之间的最小轨道激发质量分裂可以接近$100$MeV，这自然澄清了具有挑战性的问题，即$P_c(4450)$和$P_c(4380)$之间的小质量分裂。该模型还可以理解$P_c(4380)$的宽衰减宽度和$P_c(4450)$的窄衰减宽度的问题。预测的新型五夸克可以从实验中得到验证，这可以反过来检验重夸克-三夸克模型。
We use constituent diquark-triquark model to explain the charmonium-pentaquark states, i.e. $P_c(4380)$ and $P_c(4450)$ which have been recently discovered by the LHCb collaboration. We analyze the color attractive configuration for the triquark and define the nonlocal wave functions for the pentaquark state for the first time, where both diquark and triquark are not a compact pointlike, but have a nonzero size. An effective diquark-triquark Hamiltonian based on spin-orbital interaction is established. One then obtain the minimum orbital excitation mass splitting between $\frac{5}{2}^+$ and $\frac{3}{2}^-$ can be near $100$MeV, which naturally clarifies the challenging issue, i.e. the small mass splitting between $P_c(4450)$ and $P_c(4380)$. The issue that broad decay width of $P_c(4380)$ and narrow decay width of $P_c(4450)$ can also be understood in this model. The predicted novel pentaquarks can be tested from experiment, which can inspect the diquark-triquark model conversely.