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arXiv 2011.01915hep-phhep-exhep-latnucl-th
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从有效场论和唯象的观点研究$P_{cs}(4459)$五夸克态

The $P_{cs}(4459)$ pentaquark from a combined effective field theory and phenomenological perspective

Fang-Zheng Peng, Mao-Jun Yan, Mario Sánchez Sánchez, Manuel Pavon Valderrama

备注：
16 pages, 1 figure; includes discussions on power counting, the J=1/2,3/2 hyperfine splitting, saturation, phenomenological relation between the Pcs(4459) and Pc(4440/4457) potentials, decay to $J/ψΛ$, etc
发表信息：
Eur. Phys. J. C 81, 666 (2021)
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摘要：

LHCb合作对$P_{cs}(4459)$的观测为已知的隐藏魅力五夸克组增加了一个新成员，其中包括$P_c(4312)$，$P_c(4440)$和$P_c(4457)$。预计$P_{cs}(4459)$具有$Λ$重子（$I=0$，$S=-1$）的轻夸克含量，但其自旋未知。它与$\bar{D}^* Ξ_c$阈值（$4478\,{\rm MeV}$处于同位旋对称极限）的接近性表明分子假说是$P_{cs}(4459)$的合理解释。虽然在没有耦合通道动力学的情况下，重夸克自旋对称性预测$\bar{D}^* Ξ_c$的两个自旋态是简并的，但功率计数参数表明与附近的$\bar{D} Ξ_c'$和$\bar{D} Ξ_c^*$通道的耦合可能是一个领先的顺序效应。这产生了一个超精细分裂，其中$J=\tfrac{3}{2}$ $\bar{D}^* Ξ_c$五夸克态将比$J=\tfrac{1}{2}$组态轻，我们估计其量级为$5-15\,{\rm MeV}$。我们还指出了一个偶然的对称性之间的$P_{cs}(4459)$和$P_c(4440/4457)$潜力。最后，我们认为，光谱和$J/ψΛ$衰变的$P_{cs}(4459)$可能表明一个边际偏好$J = \tfrac{3}{2}$超过$J = \tfrac{1}{2}$。

英文摘要：

The observation of the $P_{cs}(4459)$ by the LHCb collaboration adds a new member to the set of known hidden-charm pentaquarks, which includes the $P_c(4312)$, $P_c(4440)$ and $P_c(4457)$. The $P_{cs}(4459)$ is expected to have the light-quark content of a $Λ$ baryon ($I=0$, $S=-1$), but its spin is unknown. Its closeness to the $\bar{D}^* Ξ_c$ threshold -- $4478\,{\rm MeV}$ in the isospin-symmetric limit -- suggests the molecular hypothesis as a plausible explanation for the $P_{cs}(4459)$. While in the absence of coupled-channel dynamics heavy-quark spin symmetry predicts the two spin-states of the $\bar{D}^* Ξ_c$ to be degenerate, power counting arguments indicate that the coupling with the nearby $\bar{D} Ξ_c'$ and $\bar{D} Ξ_c^*$ channels might be a leading order effect. This generates a hyperfine splitting in which the $J=\tfrac{3}{2}$ $\bar{D}^* Ξ_c$ pentaquark will be lighter than the $J=\tfrac{1}{2}$ configuration, which we estimate to be of the order of $5-15\,{\rm MeV}$. We also point out an accidental symmetry between the $P_{cs}(4459)$ and $P_c(4440/4457)$ potentials. Finally, we argue that the spectroscopy and the $J/ψΛ$ decays of the $P_{cs}(4459)$ might suggest a marginal preference for $J = \tfrac{3}{2}$ over $J = \tfrac{1}{2}$.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

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