Stable double-heavy tetraquarks: spectrum and structure

TL;DR

This paper investigates double-heavy tetraquarks using a constituent quark model, discovering multiple bound states with varying structures, including deeply bound compact states and loosely bound molecular states, aligning with lattice QCD results.

Contribution

It demonstrates for the first time that different types of hadrons can emerge from a single Hamiltonian in the study of double-heavy tetraquarks.

Findings

Identified two bound states in the bbar{u}ar{d} channel with different structures.

Found a total of ten bound states across various configurations.

Observed systematic decrease in binding energy with lighter heavy quarks.

Abstract

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 bb\bar{u}\bar{d} 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.