# The Hydrogen Bond of QCD

## TL;DR

This paper proposes a novel QCD molecular model for exotic hadrons, using the Born-Oppenheimer approximation, revealing stable doubly heavy tetraquarks and new insights into the structure of exotic resonances.

## Contribution

It introduces a QCD analog of the hydrogen bond to describe exotic hadrons and confirms the stability of doubly heavy tetraquarks against strong decays.

## Key findings

- Exotic resonances X and Z may be QCD molecular states.
- Doubly heavy tetraquarks are stable against strong decays.
- A new molecular picture of exotic hadrons is proposed.

## Abstract

Using the Born-Oppenheimer approximation, we show that exotic resonances, X and Z, may emerge as QCD molecular objects made of colored two-quark lumps, states with heavy-light diquarks spatially separated from antidiquarks. With the same method we confirm that doubly heavy tetraquarks are stable against strong decays. Tetraquarks described here provide a new picture of exotic hadrons, as formed by the QCD analog of the hydrogen bond of molecular physics.