论文标题
如何揭示三个或以上的五夸克州的性质？
How to reveal the nature of three or more pentaquark states?
论文作者
论文摘要
在手性统一的方法中，借助重夸克自旋对称性的约束，我们研究了$ {\ bar d}^{（*）}σ_C^{（*）} $ channels的耦合通道相互作用，该通道与lhcbbssection报告了三个pentaquark like $ p_c $ nates。在目前的工作中，我们考虑了通过框图对相互作用势的触发交换的贡献，因此提高了$ {\ bar d}^*σ_c^{（*）} $ spin多重多重质量的质量中的退化。将$ j/ψp$不变的质量分布安装在$λ_b^0 \中\ j/ψk^ - p $衰减，我们发现在直接的$ J/ψp$中，LHCB pentaquark态在$λ_b^0 $ decay中不能在直接$ j/ψp$中复制，并且只能在$ decay decay de $ depies $ de $ depions $ neties depions^0 $ {\ bar d}^*σ_c^{（*）} $，它进一步支持这些状态的性质为$ \ bar {d}σ_c$分子。根据获得的拟合结果，我们研究了与其他衰减通道的部分衰减宽度/分支比率，$ \ bar {d}^*λ_c$，$ \ bar {d}λ_c$和$η_cn $，以及相应的不变质量分布。与$ j^p = \ frac {1} {2}^ - $，$ p_c（4312）$，$ p_c（4440）$和$ \ bar {d}^*σ_c^* $ 4500 meV的$ houd $ to $ to $ hount $ n $ n $ n $η_分布。相比之下，具有$ j^p = \ frac {3} {2}^ - $，$ p_c（4457）$的状态，（预测的）窄$ p_c（4380）$和$ \ bar {d}^*σ_c^* $的限制状态，大约是4520 mev，decay $ decacy n $ not $。因此，将来应该研究$η_cn $通道，以提供对这些状态的性质的进一步见解，尤其是$ p_c（4440）$和$ p_c（4457）$的状态。
Within the chiral unitary approach and with the constraints of heavy quark spin symmetry, we study the coupled channel interactions of ${\bar D}^{(*)}Σ_c^{(*)}$ channels, close to whose thresholds three pentaquark-like $P_c$ states have been reported by the LHCb Collaboration. In the present work, we take into account the contributions of pion exchanges via box diagrams to the interaction potentials, and therefore lift the degeneracy in the masses of ${\bar D}^*Σ_c^{(*)}$ spin multiplets. Fitting the $J/ψp$ invariant mass distributions in the $Λ_b^0 \to J/ψK^- p$ decay, we find that the LHCb pentaquark states can not be reproduced in the direct $J/ψp$ production in the $Λ_b^0$ decay, and can only be indirectly produced in the final state interactions of the $Λ_b^0$ decay products, ${\bar D}^*Σ_c^{(*)}$, which further supports the nature of these states as $\bar{D}Σ_c$ molecules. Based on the fit results obtained, we study the partial decay widths/branching ratios to other decay channels, $\bar{D}^* Λ_c$, $\bar{D} Λ_c$, and $η_c N$, and the corresponding invariant mass distributions. The resonances with $J^P=\frac{1}{2}^-$, $P_c(4312)$, $P_c(4440)$ and the one of $\bar{D}^* Σ_c^*$ around 4500 MeV, have large partial decay width into $η_c N$, and thus, can be easily seen in the $η_c N$ invariant mass distributions. By contrast, the states with $J^P=\frac{3}{2}^-$, $P_c(4457)$, the (predicted) narrow $P_c(4380)$ and the bound state of $\bar{D}^* Σ_c^*$ with a mass of about 4520 MeV, do not decay into $η_c N$. Therefore, the $η_c N$ channel should be studied in future to provide further insights into the nature of these states, especially that of the $P_c(4440)$ and $P_c(4457)$.
