摘要
在粒子物理标准模型中,强相互作用由量子色动力学(quantum chromodynamics,QCD)描述.尽管QCD在高能标下的渐进自由特性已经得到大量实验验证,但人们对QCD在低能标下的非微扰特性仍然知之甚少,而强相互作用的夸克禁闭现象长期以来一直是世界难题.强子谱学是理解强相互作用的重要手段.五夸克态作为奇特强子态具有丰富的内部结构,为研究强相互作用提供了独特的平台.自2015年LHCb实验首次发现五夸克态以来,关于五夸克态的理论和实验研究相互促进,均得到了快速发展.本文将介绍LHCb实验在五夸克态研究中取得的进展,并展望LHCb新的运行取数和未来升级计划为五夸克态研究带来的机遇.
In the Standard Model of particle physics,the strong interaction is described by quantum chromodynamics(QCD).Although the asymptotic freedom of QCD at high energies has been extensively validated through experiments,our understanding of its non-perturbative characteristics at low energies remains limited,with the phenomenon of quark confinement in strong interactions being a longstanding global challenge.Hadron spectroscopy serves as a crucial means for understanding strong interactions.Pentaquark states,as one kind of exotic hadronic states with rich internal structures,provide a unique platform for studying strong interactions.Since the first discovery of pentaquark states by the LHCb experiment in 2015,both theoretical and experimental research on pentaquark states has developed rapidly,promoting each other.In this paper,we will introduce the progress made by the LHCb experiment in the study of pentaquark states,and look forward to the opportunities for pentaquark research brought by the new data taken and the future upgrade program from the LHCb experiment.The experimental search for pentaquark states has a long and controversial history,especially in early 2000s.However,the situation changed in 2015 when the LHCb experiment discovered several pentaquark candidates decaying into J/Ψp inΛ_(b)^(0)→J/ΨpK~-decays.This was a major turning point in exotic baryon spectroscopy.In 2015,the LHCb experiment reported observations of J/Ψp resonance structures in the decay of Λ_(b)^(0)→J/ΨpK~-,consistent with the hidden-charm pentaquark state with quark component ■.Initial observations showed a broader P_(c)(4380)^(+) and a narrower P_(c)(4450)^(+)resonance state.More recent results in 2019 have shown finer pentaquark structures.The peak at 4450 MeV was resolved into two states of P_(c)(4440)^(+)and P_(c)(4457)^(+).In addition,a new narrower peak P_(c)(4312)^(+) was observed.But the wider P_(c)(4380)^(+) state awaits further confirmation.Due to the SU(3) flavour symmetry,one would expect the existence of strang
作者
张黎明
傅金林
蔡浩
Liming Zhang;Jinlin Fu;Hao Cai(Department of Engineering Physics,Tsinghua Universiy,Bejing 100084,China;University of Chinese Academy of Sciences,Beijing 100089,China;School of Physical Science and Technology,Wuhan University,Wuhan 430072,China)
出处
《科学通报》
EI
CAS
CSCD
北大核心
2024年第31期4540-4549,共10页
Chinese Science Bulletin
基金
国家自然科学基金(12061141007)资助。
