隐藏粲五夸克态与LHCb观测到的$P_{c}$态的性质
Hidden charm pentaquarks and the nature of $P_{c}$ states observed at LHCb
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中文总结 AI 辅助
在半相对论势夸克模型中统一研究隐藏粲五夸克态，发现LHCb观测到的$P_c$态可解释为强子分子，并阐明介子交换在束缚态形成中的关键作用。
中文摘要 AI 辅助
我们在半相对论势夸克模型框架内，对由隐藏粲五夸克$qqqc\bar{c}$（$q=u,d$）组成的低能$1S$波紧致态和强子分子进行了统一研究。除了夸克和/或反夸克之间的线性禁闭势和单胶子交换势外，我们还考虑了五夸克系统内重子和介子团簇之间的单玻色子交换势。我们还通过夸克交换模型，结合所获得的光谱，评估了衰变（fall-apart decays）。研究发现，LHCb合作组在2019年观测到的$P_c (4312)^+$、$P_c (4440)^+$和$P_c (4457)^+$可以分别很好地解释为$[\Sigma_c\bar{D}]_{1/2^-}^{1/2}(4318)$、$[\Sigma_c\bar{D}^*]_{1/2^-}^{1/2}(4437)$和$[\Sigma_c\bar{D}^*]_{3/2^-}^{1/2}(4458)$强子分子。同时，LHCb在2015年报告的$P_c(4380)^+$可能被指定为分子$[\Sigma_c^*\bar{D}]_{3/2^-}^{1/2}(4382)$，但该态表现为窄态，而非实验数据所示的宽态。我们的研究表明，$\sigma$和$\rho$介子交换对于形成同位旋$I=1/2$的$\Sigma_c^{(*)}\bar{D}^{(*)}$束缚态至关重要。根据$\sigma$交换的势强度，可能存在同位旋$I=1/2$的$\Lambda_c\bar{D}^{(*)}$和同位旋$I=3/2$的$\Sigma_c^{(*)}\bar{D}^{(*)}$的非常浅的束缚态。我们的研究可为未来实验中进一步探索隐藏粲五夸克态提供有用信息。
英文摘要
We carry out a unified study of the low-lying $1S$-wave compact states and hadronic molecules composed of hidden charm pentaquarks $qqqc\bar{c}$ ($q=u,d$) within a semirelativistic potential quark model. Apart from the linear confinement and one-gluon exchange potential between quarks and/or antiquarks, one-boson exchange potential is also included for baryon and meson clusters within the pentaquark system. We also evaluate the fall-apart decays by combining the obtained spectra within the quark exchange model. It is found that the $P_c (4312)^+$, $P_c (4440)^+$, and $P_c (4457)^+$ observed by the LHCb Collaboration in 2019 can be well explained by the hadronic molecules of $[Σ_c\bar{D}]_{1/2^-}^{1/2}(4318)$, $[Σ_c\bar{D}^*]_{1/2^-}^{1/2}(4437)$, and $[Σ_c\bar{D}^*]_{3/2^-}^{1/2}(4458)$, respectively. Meanwhile, $P_c(4380)^+$ reported by LHCb in 2015 may be assigned as the molecule $[Σ_c^*\bar{D}]_{3/2^-}^{1/2}(4382)$, except that it turns to be a narrow state other than a broad one shown by the experimental data. Our study shows that the $σ$- and $ρ$-meson exchanges are crucial for the formation of $Σ_c^{(*)}\bar{D}^{(*)}$ bound states with isospin $I=1/2$. Depending on the potential strength of the $σ$ exchange, there may exist very shallow bound states of $Λ_c\bar{D}^{(*)}$ with isospin $I=1/2$ and $Σ_c^{(*)}\bar{D}^{(*)}$ with isospin $I=3/2$. Our study may provide useful information for further exploring the hidden-charm pentaquarks in future experiments.
发表机构
- Hunan Normal University（湖南师范大学）
- Institute of High Energy Physics, Chinese Academy of Sciences（中国科学院高能物理研究所）
- University of Chinese Academy of Sciences（中国科学院大学）
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