Anti Helium

[Diamond Cross]

ScienceDaily (Apr. 25, 2011) — 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 STAR experiment is uniquely capable of finding antihelium-4," says the STAR experiment's spokesperson, Nu Xu, of the Nuclear Science Division (NSD) at Lawrence Berkeley National Laboratory (Berkeley Lab). "STAR already holds the record for massive antiparticles, last year having identified the anti-hypertriton, which contains three constituent antiparticles. With four antinucleons, antihelium-4 is produced at a rate a thousand times lower yet. To identify the 18 examples required sifting through the debris of a billion gold-gold collisions."


Collisions of energetic gold nuclei inside STAR briefly recreate conditions in the hot, dense early universe only millionths of a second after the big bang. Since equal amounts of matter and antimatter were created in the big bang they should have completely annihilated one another, but for reasons still not understood, only ordinary matter seems to have survived. Today this excess matter forms all of the visible universe we know.


Roughly equal amounts of matter and antimatter are also produced in heavy-ion (gold nuclei) collisions at RHIC. The resulting fireballs expand and cool quickly, so the antimatter can avoid annihilation long enough to be detected in the Time Projection Chamber at the heart of STAR.

Rest of the story here:

Anti-helium discovered in Relativistic Heavy Ion Collider experiment

 

[Tharian]

And when I first saw the thread title, I thought this was going to be about how some folks are against those great balloons you can give kids before they let them go and they get stuck against the ceiling.

 

[Theo R Cwithin]

The most interesting factoid about anti-helium is that when you inhale a chestful, it makes you talk in a zany anti-MickeyMouse voice. It's great fun at kids' birthday parties, at least up until you explode in a burst of gamma rays.

 

[MarkB]

At first I was slightly freaked out by the concept of scientists deliberately creating larger and more complex amounts of antimatter. But now I'm freaked out by the idea that this machine contains a Time Projection Chamber. I'm not sure whether to be more worried for the future, or for the past.

 

[jonesy]

The most interesting factoid about anti-helium is that when you inhale a chestful, it makes you talk in a zany anti-MickeyMouse voice. It's great fun at kids' birthday parties, at least up until you explode in a burst of gamma rays.

No, that's Sulfur Hexafluoride. And it doesn't explode. Obviously.

 

[Umbran]

And when I first saw the thread title, I thought this was going to be about how some folks are against those great balloons you can give kids before they let them go and they get stuck against the ceiling.

Well, maybe they should be - as it stands now, the US faces a helium shortage.

 

[Relique du Madde]

Well, maybe they should be - as it stands now, the US faces a helium shortage.

Don't worry, we can always go to the moon an mine us some...


Oh yeah, I forgot Obama killed NASA and decided to de-fund all of Bush's proposed space debacles to get to Mars by 2050.

Hopefully the Chinese, the Indians, or Euros will lend us some helium rocks.

 

[Rhun]

Pretty cool research.

 

[Scott DeWar]

some times i wonder where the world will be in two years, or if the anti-mater expiraments will be the source of the great disater.

 

[Welverin]

some times i wonder where the world will be in two years, or if the anti-mater expiraments will be the source of the great disater.

They create far to little to make any sort of disaster, much less a great one.