Stable double-heavy tetraquarks: Spectrum and structure

Bound states of double-heavy tetraquarks are studied in a constituent quark model. Two bound states are found for isospin and spin-parity I(J(P)) =0(1(+)) in the bbud channel. One is deeply bound and compact made of colored diquarks, while the other is shallow and extended as a BB* molecule. The former agrees well with lattice QCD results. A systematic decrease in the binding energy is seen by replacing one of the heavy quarks to a lighter one. Altogether we find ten bound states. It is shown for the first time that hadrons with totally different natures emerge from a single Hamiltonian. (C) 2021 The Authors. Published by Elsevier B.V.

Automated summary

In this study, bound states of double-heavy tetraquarks are investigated using a constituent quark model. Two bound states with different properties are found in the bbud channel, one being deeply bound and compact made of colored diquarks, while the other is shallow and extended as a BB* molecule. By replacing one heavy quark with a lighter one, a systematic decrease in binding energy is observed, leading to the discovery of a total of ten bound states. It is the first time that hadrons with completely different natures have emerged from a single Hamiltonian.