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In the brief periods that the quark-gluon plasma exists, particles and antiparticles are equally probable, leading to a large collection of heavy and light nuclei and anti-nuclei. It also leads to some fantastic sentences, like the following: “Hypernuclei bring a third dimension into play, based on the strangeness quantum number of the nucleus, thus allowing the territory of antinuclei with nonzero strangeness.”
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 (Formula) and 157 ± 30 hypertritons (Formula). The measured yields of Formula (Formula) and 3He (3Formula) 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.
2010-03-07 | achtphasen | 23:27:41 | 
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