Do antimatter atoms exist naturally in the Universe?

Determine whether antimatter atoms, such as antihydrogen or heavier antiatoms, exist in nature somewhere in the Universe, as opposed to only being produced artificially in laboratory settings.

Background

The article explains that in quantum field theory, particles and antiparticles are excitations of the same field and that particle–antiparticle pairs are often produced in high-energy processes. While antihydrogen atoms have been created in laboratories since 1995—primarily at CERN’s Antimatter Factory—the text emphasizes that the natural occurrence of antiatoms in the Universe remains unresolved.

This question links to broader searches in cosmic rays for antinuclei and to astrophysical scenarios that might harbor primordial antimatter structures, but the paper notes that, so far, convincing natural antiatom detections have not been made.