Observation of an Antimatter Hypernucleus

TL;DR

This paper reports the first observation of antihypertritons produced in high-energy gold nucleus collisions, revealing insights into antimatter, strange quark behavior, and conditions similar to the early universe.

Contribution

It presents the first experimental detection of antihypertritons in high-energy nuclear collisions, demonstrating equilibrium in strange and non-strange quark populations.

Findings

Observation of 70 ± 17 antihypertritons and 157 ± 30 hypertritons.

Similar yields of hypertriton and helium3 suggest quark equilibrium.

Implications for antimatter, strange quark physics, and early universe conditions.

Abstract

Nuclear collisions recreate conditions in the universe microseconds after the Big Bang. Only a very small fraction of the emitted fragments are light nuclei, but these states are of fundamental interest. We report the observation of antihypertritons - composed of an antiproton, antineutron, and antilambda hyperon - produced by colliding gold nuclei at high energy. Our analysis yields 70 +- 17 antihypertritons and 157 +- 30 hypertritons. The measured yields of hypertriton (antihypertriton) and helium3 (antihelium3) are similar, suggesting an equilibrium in coordinate and momentum space populations of up, down, and strange quarks and antiquarks, unlike the pattern observed at lower collision energies. The production and properties of antinuclei, and nuclei containing strange quarks, have implications spanning nuclear/particle physics, astrophysics, and cosmology.