The Dynamical Diquark Model: Fine Structure and Isospin

Abstract

We incorporate fine-structure corrections into the dynamical diquark model of multiquark exotic hadrons. These improvements include effects due to finite diquark size, spin-spin couplings within the diquarks, and most significantly, isospin-dependent couplings in the form of pionlike exchanges assumed to occur between the light quarks within the diquarks. Using a simplified two-parameter interaction Hamiltonian, we obtain fits in which the isoscalar $J^{PC}=1^{++}$ state---identified as the $X(3872)$---appears naturally as the lightest exotic (including all states that are predicted by the model but have not yet been observed), while the $Z_c(3900)$ and $Z_c(4020)$ decay predominantly to $J/\psi$ and ${\eta }_c$, respectively, in accord with experiment. We explore implications of this model for the excited tetraquark multiplets and the pentaquarks.

arXiv comment19 pages, no figures. Version accepted to appear in JHEP

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Cited by in corpus (13)

• Diquark Correlations in Hadron Physics: Origin, Impact and Evidence
• The Simple Spectrum of $c\bar{c}c\bar{c}$ States in the Dynamical Diquark Model
• Spectrum of the Hidden-Bottom and the Hidden-Charm/Strange Exotics in the Dynamical Diquark Model
• Hidden charm tetraquark states in a diquark model
• Fine Structure of Pentaquark Multiplets in the Dynamical Diquark Model
• The Spectrum of $P$-Wave Hidden-Charm Exotic Mesons in the Diquark Model
• Assignments of the $X(4140)$, $X(4500)$, $X(4630)$ and $X(4685)$ based on the QCD sum rules
• Doubly-Charged $T_{cc}^{++}$ States in the Dynamical Diquark Model
• Exotic Hadrons from Scattering in the Diabatic Dynamical Diquark Model
• Doubly charmed hexaquarks in the diquark picture
• Radiative Transitions of Charmoniumlike Exotics in the Dynamical Diquark Model
• Spectrum of Hidden-Charm, Open-Strange Exotics in the Dynamical Diquark Model
• Hadronic molecules and multiquark states