Mass spectra of hidden heavy-flavor tetraquarks with two and four heavy quarks

Abstract

Inspired by the observation of the $X(6900)$ by LHCb and the $X(6600)$ (with mass $6552\pm 10$ $\pm 12$ MeV) recently by CMS and ATLAS experiments of the LHC in the di-$J/\Psi$ invariant mass spectrum, we systemically study masses of all ground-state configurations of the hidden heavy-flavor tetraquarks $q_1{Q}_2{\bar{q}}_3{\bar{Q}}_4$ and $Q_1{Q}_2{\bar{Q}}_3{\bar{Q}}_4$ ($Q=c,b$;$q=u,d,s$) contaning two and four heavy quarks in the MIT bag model with chromomagnetic interaction and enhanced binding energy. Considering color-spin mixing due to chromomagnetic interaction, our mass computation indicates that the observed $X(6600)$ is likely to be the $0^{++}$ ground states of hidden-charm tetraquark $cc\bar{c}\bar{c}$ with computed masses $6572$ MeV, which has a $0^{++}$ color partner around $6469$ MeV. The fully bottom system of tetraquark $bb\bar{b}\bar{b}$ has masses of 19685 MeV and 19717 MeV for the the $0^{++}$ ground states. Further computation is given to the tetraquark systems $sc\bar{s}\bar{c}$, $sb\bar{s}\bar{b}$, $cb\bar{c}\bar{b}$, $nc\bar{n}\bar{c}$ and $nb\bar{n}\bar{b}$, suggesting that the $Z_c(4200)$ is the tetraquark $nc\bar{n}\bar{c}$ with $J^{PC}=1^{+-}$. All of these tetraquarks are above their lowest thresholds of two mesons and unstable against the strong decays.

References in corpus (24)

• Observation of a narrow charmonium-like state in exclusive B+ -> K+ pi+pi- J/psi decays
• Observation of a New Narrow Charmonium State in Exclusive B+-->K+ pi+pi- J/psi Decays
• Observation of a charged charmoniumlike structure in e+e- to pi+pi-J/psi at \sqrt{s}=4.26 GeV
• Pentaquark and Tetraquark states
• Observation of a resonance-like structure in the pi^+- psi' mass distribution in exclusive B-->K pi^+- psi' decays
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• Baryons with two heavy quarks: Masses, production, decays, and detection
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• Hunting for exotic doubly hidden-charm/bottom tetraquark states
• Heavy-flavored tetraquark states with the $QQ\bar{Q}\bar{Q}$ configuration
• Four-quark spectroscopy within the hyperspherical formalism
• Tetraquarks composed of 4 heavy quarks
• All-heavy tetraquarks
• Analysis of the $QQ\bar{Q}\bar{Q}$ tetraquark states with QCD sum rules
• All-charm tetraquarks
• Analysis of the vector and axialvector $QQ\bar{Q}\bar{Q}$ tetraquark states with QCD sum rules
• Masses and magnetic moments of hadrons with one and two open heavy quarks: heavy baryons and tetraquarks
• A model-independent confirmation of the $Z(4430{)}^{-}$ state
• Fully heavy pentaquarks
• Quark-level analogue of nuclear fusion with doubly-heavy baryons

Cited by in corpus (4)

• P-wave fully charm and fully bottom tetraquark states
• Strong decays of the fully-charm tetraquark states with explicit P-waves via the QCD sum rules
• Possible bound states in the triple-${\eta }_c$ and triple-$J/\psi$ systems
• Prospects for compact hexaquarks under the limitation imposed by quark confinement