# Can quarks and antiquarks exist in an atom without annihilating?

Elaborating on antimatter, where atoms consist of antiprotons, antineutrons, and positrons

Is it possible to have something in between? with antiprotons, positrons, and regular neutrons? Can such an atom exist in a stable mode without the anti-upquarks annihilating the upquarks and likewise for the antidowns and downs?

Taking, for simplicity, an example analogous to deuterium, an atom consisting of an antiproton, a neutron and a positron. Is then the reaction$$\bar{u}\bar{u}\bar{d}+udd\rightarrow\bar{u}d+Energy$$inevitable? Or can these quarks/antiquarks exist safely confined within their respective particle in the nucleus to make a stable atom?

• @CosmasZachos No, antiprotons (negatively charged) would attract positions (positively charged), resulting in the same closed orbits seen in atomic physics. What matters is whether neutrons are problematic.
– J.G.
Sep 14, 2021 at 13:41
• @J.G. sorry, you are right... I was turned around... Sep 14, 2021 at 14:09