Strange pentaquarks and excited Ξ-hyperons in Ξ-b →J/ψ∧K-final states

• 作者: Marek Karliner Jonathan L.Rosner
• 来源期刊: 科学通报（英文版）
• 年，卷（期）: 2021,（13）
• 所属期刊栏目: NEWS & VIEWS
• 页码范围: 1256-1257
• 页数: 2页
• 语种: 英文

摘要

Besides the observed quark-antiquark and three-quark states,the quark model predicts other states with integral charges,such as qq(qq)(tetraquarks)and qqqq(q)(pentaquarks).In 2015,the LHCb Collaboration observed J/ψp resonances consistent with pen-taquarks in∧0b→ J/ψpK-decays[1],with minimal quark content ccuud.Two states were seen:a narrow one at 4450 MeV and a broader one at 4380 MeV.A subsequent analysis with more data[2]resolved the peak at 4450 MeV into two,separated by 17 MeV,and discovered another narrow one at 4312 MeV.Ref.[2]employed a one-dimensional analysis of the J/ψp spectrum,which is not sensitive to a broad state like Pc(4380),so the final verdict on the latter will have to wait till an amplitude analysis of the additional data.The low-mass peak may be a J=1/2 ∑C(D)S-wave molecule,while the two upper ones may be J=1/2 and 3/2 S-wave molecules of ∑C(D)* separated by hyperfine splitting.