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Antihelium Discovered By STAR 94

Posted by Soulskill from the makes-your-voice-really-low-then-vaporizes-your-lungs dept.
Medevilae writes with this excerpt from ScienceBlog: "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 US Department of Energy's Brookhaven National Laboratory. ... Ordinary nuclei of helium atoms consist of two protons and two neutrons. Called alpha particles when emitted in radioactive decays, they were found in this form by Ernest Rutherford well over a century ago. The nucleus of antihelium-4 (the anti-alpha) contains two antiprotons bound with two antineutrons. ... 'It’s likely that antihelium will be the heaviest antiparticle seen in an accelerator for some time to come,' says STAR Collaboration member Xiangming Sun of Berkeley Lab’s NSD. '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.'"
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Antihelium Discovered By STAR More

Antihelium Discovered By STAR

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  • Here comes the alchemy (Score:5, Funny)

    by tibbetts ( 7769 ) <jason@@@tibbetts...net> on Monday April 25, 2011 @01:04PM (#35932066) Homepage Journal
    We're that much closer to mastering alchemy, because someday we'll be able to produce anti-antimony, i.e. mon(e)y.

  • Stuff that anti-matters? (Score:4, Funny)

    by erroneus ( 253617 ) on Monday April 25, 2011 @01:08PM (#35932134) Homepage

    I guess Slashdot is expanding its scope to include stuff that anti-matters as well! And now it seem they are trying to up their anti- by trying to produce larger and more complex stable anti-atoms?

    • As opposed to its current production of antipathy?

    • I was anticipating someone was going to post something like this. Oh slashdot, you and your anticlimactic antics of antique natures.

    • >I guess Slashdot is expanding its scope to include stuff that anti-matters as well!

      I thought that was Idle.

    • I knew this username was bound to pay off some day.

    • I guess Slashdot is expanding its scope to include stuff that anti-matters as well! And now it seem they are trying to up their anti- by trying to produce larger and more complex stable anti-atoms?

      Pshaw, we've had RSS on here for years already!

  • No Positrons, No Anti-matter (Score:5, Interesting)

    by Covalent ( 1001277 ) on Monday April 25, 2011 @01:11PM (#35932186)
    Without positrons (anti-electrons) orbiting the nucleus, these are just high energy anti-particles. Technically anti-matter, but not really available for interesting study. What would be much more interesting would be molecular anti-hydrogen, complete with positron bonding. Then you could test many properties of anti-matter. But cooling and storing is still a major problem. This is an interesting discovery, but we're no closer to really understanding anti-matter because of it (or, for that matter, having warp drive.)

    • Re:No Positrons, No Anti-matter (Score:4, Interesting)

      by doconnor ( 134648 ) on Monday April 25, 2011 @01:23PM (#35932364) Homepage

      Quirks and Quarks had a story [www.cbc.ca] a few months ago about the quest to make anti-hydrogen.

    • Re: (Score:2)

      by ae1294 ( 1547521 )

      Without positrons (anti-electrons) orbiting the nucleus, these are just high energy anti-particles. Technically anti-matter, but not really available for interesting study.

      What would be much more interesting would be molecular anti-hydrogen, complete with positron bonding. Then you could test many properties of anti-matter.

      But cooling and storing is still a major problem. This is an interesting discovery, but we're no closer to really understanding anti-matter because of it (or, for that matter, having warp drive.)

      Whhhaaat? Positron bonding is the easy part.... big hunks of negative particles love positive particles...

      • The charge is used to isolate the particle. Once it is positron bound, it is overall neutral. How do you isolate it?

    • Re: (Score:3)

      by gr8_phk ( 621180 )

      Without positrons (anti-electrons) orbiting the nucleus, these are just high energy anti-particles. Technically anti-matter, but not really available for interesting study. What would be much more interesting would be molecular anti-hydrogen, complete with positron bonding.

      But at least the nuclei stand a chance of magnetic confinement. Neutral atoms not so much.

    • It may not be an atom, but they did produce two antiprotons and two antineutrons bound by the strong force. AFAIK that's never been observed before, and it does count for something. Also, the heavier these things are, the easier they are to cool, so it may not be long before someone can produce "real" antihelium.

      • Re: (Score:2)

        by Belial6 ( 794905 )
        My question though is, what is an anti-neutron? If it is in the nucleus, and it has a neutral charge, what is the difference?

        • Re: (Score:3)

          by jo_ham ( 604554 )

          It has the opposite magnetic moment, and various other properties that are reversed compared to a normal neutron.

    • Without positrons (anti-electrons) orbiting the nucleus, these are just high energy anti-particles. Technically anti-matter, but not really available for interesting study. What would be much more interesting would be molecular anti-hydrogen, complete with positron bonding. Then you could test many properties of anti-matter. But cooling and storing is still a major problem. This is an interesting discovery, but we're no closer to really understanding anti-matter because of it (or, for that matter, having warp drive.)

      Not really sure why this got modded up... There's no such thing as "technically" antimatter vs "really" antimatter. Helium is still helium even without the electrons (elements are designated by their number of protons or anti-protons and has nothing to do with their electrons). It just has an ionic charge (ie. plasma, alpha particle). Anti-helium is not an exception. It IS really available for interesting study or you wouldn't be reading the article. And making it a "whole" atom by adding positrons would RE

  • Does it make your voice really low (Score:4, Funny)

    by bareman ( 60518 ) on Monday April 25, 2011 @01:14PM (#35932244) Homepage Journal

    when you inhale it?

    • Re: (Score:2)

      by ae1294 ( 1547521 )

      when you inhale it?

      No... it would make it high... it's lighter than air.. I won't recommend it though... Wait.. no... I would recommend it.. make sure you film it for us...

    • Yes, but side-effects also include pulling your entire body towards the earth's core as if you were being yanked by a tow truck right through the upper crust.

  • I already prepping my Barry White impersonation.

  • he cried as he dragged the heavy weight behind him

  • Anti-helium has a mass exactly equal (well, if CPT is a good symmetry) to helium. The mass of helium is roughly 4 amu, which is ~4 GeV. The mass of the top quark is *significantly* more than that. The mass of the top (and antitop) is 172 GeV.

    • Try RTFS and/or RTFA:

      It’s likely that antihelium will be the heaviest antiparticle seen in an accelerator for some time to come..

  • How anticlimactic.
  • 'After antihelium the next stable antimatter nucleus would be antilithium'

    Then we can have deep voices and even worse mood swings.
  • Comment removed based on user account deletion

    • Re:Okay, I get some of this . . . (Score:5, Informative)

      by pclminion ( 145572 ) on Monday April 25, 2011 @01:42PM (#35932678)

      An anti-neutron is like a neutron, but instead of being composed of an up quark and two down quarks, it is composed of an anti-up quark and two anti-down quarks. Each of the quarks has an electrical charge -- they add in such a way that the sum is zero. For an anti-neutron, the quarks have the opposite charges as before, but they still all add to zero.

    • Re:Okay, I get some of this . . . (Score:4, Informative)

      by Ironchew ( 1069966 ) on Monday April 25, 2011 @01:46PM (#35932728)

      "Ordinary" neutrons would annihilate anti-protons if they got sufficiently close, i.e., to form a nucleus. On a semi-related note, I remember reading that charge-reversal isn't the only property of antimatter; it can also be thought of like quantum spin-reversal or time-reversal (ordinary matter going backwards in time). Weird stuff.

      • Re:Okay, I get some of this . . . (Score:4, Informative)

        by pclminion ( 145572 ) on Monday April 25, 2011 @01:57PM (#35932906)

        On a semi-related note, I remember reading that charge-reversal isn't the only property of antimatter; it can also be thought of like quantum spin-reversal or time-reversal (ordinary matter going backwards in time).

        That's really the most correct way to think about it. Take the electron, for instance. It always repels other electrons, period. If you get an electron going backward in time, it still repels other electrons, but because time is flipped around it looks like an attraction. It is not just charge but ALL the properties of the particle which are reversed.

        In the case of a neutron, imagine it not as a neutral particle but as an electric dipole (tripole really, but for simplicity imagine it's a dipole). When you get sufficiently far away from it, the net electric field is pretty much zero. It's not until you look at it very closely that you see the two opposite charges. Now, you can reverse those charges and still, at big distances it looks like there's no field. But you did in fact reverse the charges.

        • Re: (Score:2)

          by 3Cats ( 113616 )

          based on reading the above, my addled brain immediately thinks that all the antimatter went back in time to before the big bang,( to negative infinity and beyond,) while normal matter went forward in time. There. Solved THAT mystery.

      • Comment removed based on user account deletion

        • If you draw a Feynman diagram showing the annihilation of an electron with a positron, it looks like an electron which momentarily goes backward in time, and some photons shooting out. If you do the calculations, you get the right answer (the "answer" is the probability of it happening). That's really all you can say about it.

          It's not really like an electron goes forward in time for a while, then decides to mix it up a little and turns around and goes backward in time. It's just that there's no way to disti

      • The magnetic moment is also reversed.

  • That is the first time I've heard of a virus making a scientific discovery. I just hope the Iranians don't find a way to weaponize it.

    • Re: (Score:2)

      by ae1294 ( 1547521 )

      I just hope the Iranians don't find a way to weaponize it.

      All they need is a bag of party balloons and we are all screwed!

      You and I in a little toy shop
      Buy a bag of balloons with the money we've got
      Set them free at the break of dawn
      Til one by one, they were gone
      Back at base bugs in the software
      Flash the message, something's out there
      Floating in the summer sky
      99 red balloons go by

      99 red balloons
      Floating in the summer sky
      Panic bells it's red alert
      There's something here from somewhere else
      The war machine springs to life
      Opens up one eager eye
      Focusing it on the sky as

  • I thought anti-helium was sulphur hexafluoride [youtube.com]
  • When we run out of helium, we can manufacture anti-helium to replace it! ;)
  • The next, higher one than helium is going to be lithium? I'm gonna go out on a limb here and predict the next one after that will be beryllium.
  • From the beginning, the 10 radical isotopes are: Tucharium, -5; Dongor, -17; Lu, -31; Kartex, -79; Sharbar, -101; Ulanium, -127; Hyduron, -173; Simonsium, -211; Metite, -239; Krasnov, -307; These are the ten radical isotopes, from the beginning.
  • Does it make you sound like Paul Robeson/James Earl Jones?

  • Does anyone know if there is any possibility if antimatter might repel regular matter gravitationally? That is an experiment I would like to see. It's an assumption that the stars we see are ordinary matter. There really is no way of knowing from a distance. We don't get hit by antimatter meteors so we can tell matter and antimatter don't occur in close proximity to each other. So I total which of the following are true:

    -Antimatter is extremely rare in the universe maybe none exists today.

    -Antimatter is rep

    • I think your 2nd and 3rd assertions are false, however the first one has an interesting side note. Ever heard of a PET scan [wikipedia.org]? That's antimatter - Positron Emission Tomography. That nasty radioactive Potassium in bananas, 40K? It emits positrons (B+ decay) approximately 11% of the time. From this article [wikipedia.org]: "In a human body of 70 kg mass, about 4,400 nuclei of 40K decay per second." That's 484 positrons/sec being annihilated within your body!
      Antimatter is all around us.

    • Does anyone know if there is any possibility if antimatter might repel regular matter gravitationally?

      The idea does sound intuitively attractive, but I'm pretty sure that it doesn't work in practice. I can't recall enough physics to say why, but I don't think it's the case.

      It's an assumption that the stars we see are ordinary matter. There really is no way of knowing from a distance.

      The assumed symmetry of matter vs antimatter would preclude being able to tell the difference by spectroscopy (checking thi

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