Physicists trap a single antimatter particle for a month

(scientificamerican.com)

109 points | by mooreds 2 days ago

11 comments

  • foobarbecue 27 minutes ago
    I don't get how they know they have one in there. I mean they're measuring the magnetic field but how on earth do you make sufficiently precise measurements to detect a single particle!?!

    Edit: this is explained pretty extensively in the paper (https://cfp.physics.northwestern.edu/documents/2026OnePositr...). I'm gonna need to do some background reading though...

    • sandworm101 20 minutes ago
      They let it go and listen for the pop? Let it fall from the magnetic containment and you should see a predictable emission as it collides with some normal matter. Detecting single photons is what detectors are all about.
      • tomrod 3 minutes ago
        This made me laugh very hard. Thank you.

        I think this is a fascinating technology. I wonder if it is currently energy positive (so that we can engineer it into a functional source) or at least if it can be extended to be captured in bulk (antimatter rockets!).

  • fsh 36 minutes ago
    Exciting results. The electron's magnetic moment is probably the most precise standard model prediction, and Gabrielse's group has measured it with 13 digits of accuracy. The positron is predicted to have exactly the same magnetic moment, but this has not been measured since 1987. With the new trap, they should be able to finally match the electron's precision.
  • dguest 4 hours ago
    Direct link to article: https://arxiv.org/abs/2605.08147
  • androiddrew 1 hour ago
    I kind of want to know how they safely deal with its release (destruction)
    • gus_massa 58 minutes ago
      As the sibling comments say, it's a single positron so the energy released is tiny. I tried to find positrons sources in common life, the best I could find was https://en.wikipedia.org/wiki/Positron_emission_tomography The relevant paragraph are

      > For a typical dose (245 MBq) of FDG, one of the most common radiotracers used for PET neuroimaging and cancer patient management,[48] the effective radiation dose is 4.7 mSv.[49]

      and

      > This limitation restricts clinical PET primarily to the use of tracers labelled with fluorine-18, which has a half-life of 110 minutes and can be transported a reasonable distance before use.

      Where "245 MBq" means 2*10^8 positrons per second for. And "110 minutes" means a half disappears every 2 hours, so the total sum is equivalent to 4 hours but I'm missing some small constant and they ae probably averaging the dose. I guess "3 hours" is a good compromise but multiply it by 2 or 4 if you prefer a smaller or bigger number. Anyway, 3 hours are 10^4 seconds, so the total numbers of positrons in a PET is approximately 2*10^8 * 10^4 = 2*10^12.

      • Sharlin 29 minutes ago
        And whether it’s a positron or an electron (beta+ or beta- decay) doesn’t seem to matter that much as far as equivalent dose is concerned, the energy deposited is only fractionally higher in the case of a positron. (But PET can only work with positrons because it’s exactly the pairs of 0.511 MeV annihilation gammas that it’s designed to detect!)
      • Razengan 12 minutes ago
        > I tried to find positrons sources in common life

        Good outlook. Positive vibes only.

    • SwellJoe 1 hour ago
      It's one particle. It's not a bomb.
    • goda90 40 minutes ago
      Ejecting the warp core is a common strategy.
    • Retr0id 1 hour ago
      If it's a single particle I don't think there's much to worry about?
    • ungovernableCat 1 hour ago
      E=mc*2 but m is really really tiny
  • DoctorOetker 3 hours ago
    whats up with all the comments making analogies with AI torture repository?

    One might measure the "amount of computation going on" as a proxy for consciousness, but "number of dissipative logic gates" can't be right since one can construct larger reversible circuits containing the same computation (and hence dissipation is a poor measure), although one could then use the total number of bits (including trash bits) as the measure.

    but I don't understand why particle physics?

    having all other comments (at the time of writing) be about consciousness of individual particles, seems to indicate these commenters specifically believe particle physics or antimatter to directly describe consciousness?

    Or is this some kind of "disinfo inoculation campaign" to render us immune to "sentient rights propaganda"?

    • jatora 1 hour ago
      It's definitely just jokes due to using the word 'trap'. You might need to get some sleep lol
    • KPGv2 2 hours ago
      I don't see comments on SI's website. I assume you mean here. Those are jokes.
      • swores 47 minutes ago
        To be fair, I can see why they didn't realise that considering none of them are remotely funny.
  • pizzafeelsright 3 hours ago
    of course the cyclotron going clockwise.
  • snailshare 2 days ago
    Does this hurt the positron?
    • largbae 0 minutes ago
      The end annihilation was actually the electron switching to backwards through time. At the beginning of the experiment the positron switches back to forward and continues on its way.

      https://en.wikipedia.org/wiki/One-electron_universe

    • brenkc 5 hours ago
      Call PETA (People for the Ethical Treatment of Antimatter)
      • sirlancer 3 hours ago
        Physicists for the Ethical Treatment of Atoms
    • arj 4 hours ago
      Poor thing, all alone
      • Razengan 3 hours ago
        It could have been an entire universe, like ours, if some theories/cosmologies are correct :)
    • ggyyyg 4 hours ago
      [flagged]
  • bozdemir 4 hours ago
    That's matter cruelty. We need more ethical ways to study those poor things. Does anyone know what happened after the experiment ? Did they finally let it go?
    • tomaskafka 1 hour ago
      It was given freedom at the end of experiment, and was immediately eaten by its abundant natural predator, just like it happens in nature.
    • gcascio 3 hours ago
      Matter rights matter.
      • Scarblac 3 hours ago
        But antimatter rights antimatter? Or do they become lefts.
    • saidnooneever 2 hours ago
      I sure hope it doesnt come back for revenge damn
    • consensus1 3 hours ago
      It's worse than that. They annihilated it completely.
      • mixtureoftakes 3 hours ago
        Drawing the line at matter welfare when the world still has this much human suffering will never stop being wild to me
    • exe34 2 hours ago
      I was going to comment "I bet it's pissed" and then worried about drawing dang on myself, but you started it... Also: https://www.facebook.com/watch/?v=1254917172263794.

      "Wild? I was absolutely livid!"

  • lifeisstillgood 28 minutes ago
    The parents of the anti-matter particle then freeze time just as the containment is about to explode, allowing Picard and Geordi to wander around the facility looking for clues - until one scientists head slowly turns - they are also awake !!
  • jimnotgym 4 hours ago
    I hope they took precautions against the Camerlengo stealing it
    • ButlerianJihad 3 hours ago
      Positrons are just as Catholic as electrons: they both have the same mass!
  • shireboy 1 hour ago
    The Ackbar Effect