# The Hydrogen Bond of QCD in Doubly Heavy Baryons and Tetraquarks

## TL;DR

This paper extends the Born-Oppenheimer approximation to analyze the QCD hydrogen bond in doubly heavy baryons and tetraquarks, comparing results with existing models and lattice QCD to support a molecular picture of these exotic states.

## Contribution

It introduces a detailed treatment of the QCD hydrogen bond in doubly heavy baryons and tetraquarks using the Born-Oppenheimer approximation, providing new insights into their structure.

## Key findings

- Support for the molecular interpretation of doubly heavy exotic states
- Agreement with constituent quark model and lattice QCD results
- Enhanced understanding of the QCD hydrogen bond in heavy hadrons

## Abstract

In this paper we present in greater detail previous work on the Born-Oppenheimer approximation to treat the hydrogen bond of QCD, and add a similar treatment of doubly heavy baryons. Doubly heavy exotic resonances X and Z can be described as color molecules of two-quark lumps, the analogue of the H_2 molecule, and doubly heavy baryons as the analog of the H_2^+ ion, except that the two heavy quarks attract each other. We compare our results with constituent quark model and lattice QCD calculations and find further evidence in support of this upgraded picture of compact tetraquarks and baryons.