antihelium


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Related to antihelium: sulphur hexafluoride, sulfur hexafluoride

antihelium

[¦an·tē′hē·lē·əm]
(atomic physics)
The antimatter counterpart of helium, whose atoms each consist of two orbiting positrons and a nucleus composed of two antiprotons and either one or two antineutrons.
References in periodicals archive ?
An antihelium nucleus found in Earth's vicinity would have had a long and arduous trip.
If it did traverse intergalactic space, the antihelium nucleus would eventually cross a threshold between the antimatter region and the neighboring matter region.
Finally, if an antihelium nucleus is to be recorded, it must approach the neighborhood of the Milky Way.
Even with the enormous number of particles that would be flowing out of an antimatter galaxy, the odds of an antihelium nucleus reaching a detector near Earth are small.
I don't see any reason why, in our conventional understanding of cosmology, we would see any antihelium in the universe," says Sean Carroll of the California Institute of Technology in Pasadena.
Some scientists have suggested that any region of antimatter might be so large that antihelium particles would never make it to Earth.