Hidden-charm pentaquarks with color-octet substructure in QCD sum rules
Hidden-charm pentaquarks with color-octet substructure in QCD sum rules
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DOI：
10.1103/physrevd.101.014002
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发表时间：
2019-08
影响因子：
5
通讯作者：
A. Pimikov;H. Lee;Pengming Zhang
中科院分区：
文献类型：
--
作者：
A. Pimikov;H. Lee;Pengming Zhang
We study the hidden-charm pentaquark states $udsc\bar{c}$ with spins 1/2, 3/2, and 5/2 within the QCD sum rules approach. First, we construct the currents for the particular configuration of pentaquark states, that consist of the flavor singlet three-quark cluster $uds$ of spins 1/2 and 3/2 and the two-quark cluster $\bar cc$ of spin 1, where both clusters are in color-octet state. To obtain QCD sum rules, the operator product expansion for the correlators is performed up to dimension-10 condensates. The extracted masses from QCD sum rules for the hidden-charm pentaquark states $uds$-$\bar{c}c$ are about 4.6 GeV (5.6 GeV) for spin 1/2$^\pm$, about 5.1 GeV (6.0 GeV) for spin 3/2$^\pm$, about 6.1 GeV (5.9 GeV) for spin 5/2$^\pm$, where the masses of positive parity states given in parentheses. Additionally, based on the flavor singlet pentaquark states, it is also shown that other pentaquark states of the clusters as $udc$-$\bar{c}s$ and $usc$-$\bar cd$ lead to the similar masses to $uds$-$\bar cc$ case within error bars. Furthermore, in order to see whether any of the states, observed by LHCb Collaboration, could be understood as the pentaquark of the two clusters in the color-octet state, we study the pentaquark formed by the two clusters $udc$-$\bar cu$, where the three-quark cluster is assumed to have the same flavor structure as the above $uds$ cluster. We come to the conclusion that if the observed pentaquark will be found to have spin 1/2 and negative parity, then it could be described as a state of two color-octet clusters.
