Research Article

Observation of an Antimatter Hypernucleus

See allHide authors and affiliations

Science  04 Mar 2010:
DOI: 10.1126/science.1183980


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—comprised of an antiproton, antineutron, and antilambda hyperon—produced by colliding gold nuclei at high energy. Our analysis yields 70 ± 17 antihypertritons (H¯Λ¯3) and 157 ± 30 hypertritons (HΛ3). The measured yields of HΛ3 (H¯Λ¯3) and 3He (3He¯) 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.