发表机构
School of Physics, Peking University; School of Physics and Center of High Energy Physics, Peking University（北京大学物理学院; 北京大学物理学院和高能物理中心）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究利用神经网络变分蒙特卡洛方法系统研究五夸克系统，发现21个浅束缚分子态候选，无深束缚态，为未来五夸克搜索提供指导。
AI 中文摘要
我们使用组分夸克势模型中的神经网络变分蒙特卡洛方法，对五夸克系统的基态进行了系统研究。我们研究了所有具有负宇称的明显奇异五夸克系统，这些系统不能通过轻夸克或奇异夸克对的产生和湮灭与常规重子混合。我们穷尽了387种颜色、自旋和同位旋组态，并识别出21个五夸克束缚态候选，其结合能范围从2到15 MeV。一个引人注目的观察结果是，所有束缚态都是浅束缚分子态，不存在深束缚的五夸克态。$QQqq\bar{Q}$、$ssqq\bar{Q}$、$Qsqq\bar{Q}$和$Qqqq\bar{Q}$束缚态由一个重矢量介子和一个重子组成，而$QQqq\bar{s}$和$Qqqq\bar{s}$束缚态由一个$K$介子和一个重子组成。作为交叉验证，非束缚系统的基态能量从上方收敛到重子-介子阈值，这与S波散射态一致，并为束缚态判据提供了可靠的基线。特别是，我们在$qqqc\bar{c}$和$qqsc\bar{c}$通道中分别重现了最低散射态$\eta_c N$和$\eta_c \Lambda$，其中实验上观测到了隐粧五夸克共振。我们还发现所有全重五夸克态都是非束缚的。我们的结果为未来在LHCb、Belle II及其他实验中的五夸克搜索提供了有价值的指导。
英文摘要
We present a systematic study of the ground states of pentaquark systems using the neural network variational Monte Carlo method within the constituent quark potential model. We investigate all manifestly exotic pentaquark systems with negative parity, which cannot mix with the conventional baryons through the creation and annihilation of light or strange quark pair. We exhaust 387 color, spin, and isospin configurations and identify 21 pentaquark bound state candidates with binding energies ranging from $2$ to $15$ MeV. A striking observation is that all of the bound states are shallowly bound molecular states, and a deeply bound pentaquark state does not exist. The $QQqq\bar{Q}$, $ssqq\bar{Q}$, $Qsqq\bar{Q}$ and $Qqqq\bar{Q}$ bound states are composed of a heavy vector meson and a baryon, while the $QQqq\bar{s}$ and $Qqqq\bar{s}$ bound states are composed of a $K$ meson and a heavy baryon. As a cross-validation, the ground-state energies of the unbound systems converge to the baryon--meson thresholds from above, which are consistent with the S-wave scattering states and provide a reliable baseline for the bound-state criterion. Especially, we reproduce the lowest scattering states $η_c N$ and $η_c Λ$ in the $qqqc\bar{c}$ and $qqsc\bar{c}$ channels respectively, where the hidden-charm pentaquark resonances were observed experimentally. We also find that all fully heavy pentaquark states are unbound. Our results provide valuable guidance for future pentaquark searches at LHCb, Belle II, and other experiments.
Comments15 pages, 4 figures
