Baryon, my wayward son

And not just heavy particles, either: they’re finding heavy antiparticles these days. Then again, “heavy” is relative, even relativistic:

Eighteen examples of the heaviest antiparticle ever found, the nucleus of antihelium-4, have been made in the STAR experiment at RHIC, the Relativistic Heavy Ion Collider at the U.S. Department of Energy’s Brookhaven National Laboratory.

The nucleus, as you’d expect, consists of two antiprotons bound to two antineutrons; it therefore has a baryon number of -4. The next step, presumably, will be some form of antilithium, perhaps -6 or -7 — lithium has two stable isotopes, 6 and 7 — but we probably shouldn’t hold our breath:

“After antihelium the next stable antimatter nucleus would be antilithium, and the production rate for antilithium in an accelerator is expected to be well over two million times less than for antihelium.”

Of which, you’ll remember, we’ve obtained a mere dozen and a half nuclei. Still, I like the Fark blurb: “We’ve created 18 atoms of anti-helium” say giggling scientists with super deep voices.


  1. fillyjonk »

    26 April 2011 · 8:27 pm

    “Does this antineutron make me look heavy?”

  2. McGehee »

    26 April 2011 · 8:54 pm

    Anti-particles? Will the intolerance never end?

  3. Tam »

    26 April 2011 · 9:41 pm

    This title won you 200 Nerd Points from both of us at Roseholme Cottage.

  4. CGHill »

    26 April 2011 · 9:42 pm

    I am deeply honored.

  5. Dan B »

    28 April 2011 · 3:36 pm

    Actually, given the relative (lack of) abundance of lithium, beryllium, and boron (not related to OU Prez Dave, US Rep Dan, or those currently heading northbound on Broadway Extension), it may be more likely to expect anti-carbon first, despite requiring 3 times the energy and being about 1/27 as likely to appear out of the quantum foam as anti-helium.

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