Masses of fully heavy tetraquarks $$QQ {\bar{Q}} {\bar{Q}}$$ Q Q
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Regular Article - Theoretical Physics
Masses of fully heavy tetraquarks Q Q Q¯ Q¯ in an extended relativized quark model Qi-Fang Lü1,2,3,a , Dian-Yong Chen4,b , Yu-Bing Dong5,6,7,c 1
Department of Physics, Hunan Normal University, Changsha 410081, China Synergetic Innovation Center for Quantum Effects and Applications (SICQEA), Changsha 410081, China 3 Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education, Changsha 410081, China 4 School of Physics, Southeast University, Nanjing 210094, China 5 Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China 6 Theoretical Physics Center for Science Facilities (TPCSF), CAS, Beijing 100049, China 7 School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 101408, China
2
Received: 29 June 2020 / Accepted: 8 September 2020 © The Author(s) 2020
Abstract Inspired by recent measurement of possible fully charmed tetraquarks in LHCb Collaboration, we investigate the mass spectra of fully heavy tetraquarks Q Q Q¯ Q¯ in an extended relativized quark model. Our estimations indicate that the broad structure around 6.4 GeV should contain one or more ground states for ccc¯c¯ tetraquarks, while the narrow structure near 6.9 GeV can be categorized as the first radial excitation of ccc¯c¯ system. Moreover, with the wave functions of the tetraquarks and mesons, the strong decays of tetraquarks into heavy quarkonium pair are qualitatively discussed, which can be further checked by the LHCb and CMS Collaborations.
1 Introduction Since the observation of X (3872) in 2003 [1], the searching for hadrons beyond the conventional mesons and baryons have become one of intriguing topics in the past decades. On the experimental side, a growing number of new hadron states have been observed experimentally. Some of these states cannot be accommodated into the traditional mesons or baryons, which can be good candidates of molecular or tetraquark states. Recent experimental and theoretical status can be found in the literature reviews [2–10]. Among the observed new hadron states, those with heavy quark components are particularly interesting, since the spectroscopy of traditional mesons and baryons with heavy quarks are much clear than the light hadrons. Moreover, the
interactions involved heavy quarks are supposed to be dominated by the short range potential generated by one gluon exchange rather than the long range potential resulted from light meson exchanges. Thus, the new hadron states composed by four heavy quarks should be good candidates of compact tetraquark states rather than deuteron-like molecular states. A possible excess at 18.4 ± 0.1(stat.) ± 0.2(syst.)GeV/c2 in four lepton channel was reported, which may be a bbb¯ b¯ tetraquark state [11,12]. This structure is below the threshold of bottomonium meson pair, which demonstrates that the decays into bottomonium meson pair through quark rearrangement should be hindered. However, the LHCb and CMS Collaborations analyzed the invariant mass distrib
