Want to read Slashdot from your mobile device? Point it at m.slashdot.org and keep reading!

 



Forgot your password?
typodupeerror
×
Science

Particle Mystery Deepens, As Physicists Confirm That the Muon Is More Magnetic Than Predicted (sciencemag.org) 66

sciencehabit writes: A potential chink in physicists' understanding of fundamental particles and forces now looks more real. New measurements confirm a fleeting subatomic particle called the muon may be ever so slightly more magnetic than theory predicts, a team of more than 200 physicists reported this week. That small anomaly -- just 2.5 parts in 1 billion -- is a welcome threat to particle physicists' prevailing theory, the standard model, which has long explained pretty much everything they've seen at atom smashers and left them pining for something new to puzzle over. "Since the 1970s we've been looking for a crack in the standard model," says Alexey Petrov, a theorist at Wayne State University. "This may be it." But Sally Dawson, a theorist at Brookhaven National Laboratory, notes the result is still not definitive. "It does nothing for our understanding of physics other than to say we have to wait a little longer to see if it is real."

For decades, physicists have measured the magnetism of the muon, a heavier, unstable cousin of the electron, which behaves like a tiny bar magnet. They put muons in a vertical magnetic field that makes them twirl horizontally like little compass needles. The frequency at which the muons twirl reveals how magnetic they are, which in principle can point to new particles, even ones too massive to be blasted into existence at an atom smasher like Europe's Large Hadron Collider. That's because, thanks to quantum uncertainty, the muon sits amid a haze of other particles and antiparticles flitting in and out of existence. These "virtual" particles can't be observed directly, but they can affect the muon's properties. Quantum mechanics and Albert Einstein's theory of special relativity predict the muon should have a certain basic magnetism. Familiar standard model particles flitting about the muon increase that magnetism by about 0.1%. And unknown particles lurking in the vacuum could add another, unpredictable increment of change.
Further reading: Finding From Particle Research Could Rewrite Known Laws of Physics.
This discussion has been archived. No new comments can be posted.

Particle Mystery Deepens, As Physicists Confirm That the Muon Is More Magnetic Than Predicted

Comments Filter:
  • Not to dismiss fundamental work - it's fascinating and important in its own right - but is there any technology we have or are investigating that makes use of muons?
    • by MightyMartian ( 840721 ) on Wednesday April 07, 2021 @12:02PM (#61247538) Journal

      No, but that hardly invalidates basic research. Understanding the fundamental interactions of nature not only answers questions, but also leaves room open into the future for new applications. In the 18th century, electricity was a curiousity that made for neat parlor tricks like frogs legs jumping and hair standing up. Less than a century after those fascinating but pretty ineffectual tricks, the world was introduced to the first long distance high speed communication network. So finding physics beyond the Standard Model (which, let's be honest, physicists have suspected for decades now) may not have applications now, but if we manage to pierce the veil to higher energy physics, maybe we figure out a quantum theory of gravity, which could, in the future, have enormous technological ramifications.

      • by AcidFnTonic ( 791034 ) on Wednesday April 07, 2021 @01:17PM (#61247872) Homepage

        The masses act more like it's a popularity contest.

        They won't help you design or ponder about it.
        They won't help you build it because you are wrong and wasting time.
        They won't help you test it but instead actively push FUD trying to discredit you.
        They they mock you for going against the grain if they haven't stopped you yet.

        Then once you prove it all works, they demand you to give it to them for free, complain that they should be able to literally rob you of it because freedom, then call you evil for daring to keep a penny after all that hard work.

        When it's time for recognition there will be none because everyone knows how "obvious" the invention is.

        If you have ever built anything you'll see this process happen. When you fail over and over they notice. If you succeed it's because you are a thieving bastard robbing the kindness of society.

        It's a wonder people still invent shit for other people.

        • It's a wonder people still invent shit for other people.

          People I think invent things because they are driven to for themselves. I have a job which ultimately involves making things (software currently). If I was independently wealthy I would spen a good chunk of my time writing code or in a workshop.

        • by gtall ( 79522 ) on Wednesday April 07, 2021 @02:12PM (#61248078)

          Jesus, what a post-modern dystopic view of science you have. Scientists generally don't give a damn about the "masses" regardless of how they think of them. And near as I can tell, the masses don't give damn about science, certainly not enough to actively discredit it . . . except for the Christian nutjobs, but they only talk to each other and normal people pay them no mind.

          • by jythie ( 914043 )
            Eh I am guessing they have some particular slight in mind, or some strawman that they fear is coming for them, and are too simple of a person to not generalize it to 'all inventors'.
            • My guess is that they have bought into Ayn Rand's rhetoric (sounds like a paraphrase of the John Galt speech in Atlas Shrugged).
        • by sjames ( 1099 ) on Wednesday April 07, 2021 @05:10PM (#61248796) Homepage Journal

          It depends. If your great invention is rounded edges like on a speed limit sign but for a phone, nobody's impressed.

          OTOH, if you invent the transistor, it's worth something.

        • by ceoyoyo ( 59147 )

          They don't. People invent things for themselves because they're curious, idealistic, or need something that doesn't exist for their own purposes; or they invent for a select group of people who do appreciate it.

          The mass market, which you've described, mostly gets crap slapped together by shysters. Yes, they deserve it.

      • by sjames ( 1099 )

        And of course those funny rocks that always point the same way if you float them on a bit of wood sure came in handy when ships wanted to sail beyond the sight of land. Turns out all that gazing up at the stars paid off for that as well.

      • No, but that hardly invalidates basic research.

        You can't really say that yet. There are certainly not practical consequences we know of yet but you could easily have said the same of Rutherford's discovery of the nucleus or Dirac's prediction of antimatter etc. at the time they were discovered. Today nuclear physics is critical to a whole host of things from power plants to diagnosing cancer with isotopes that emit positrons (anti-electrons).

        Fundamental physics research needs 50-100 years of maturity before we can really see if it has practical appl

    • by Anonymous Coward on Wednesday April 07, 2021 @12:02PM (#61247542)
      Muon tomography [wikipedia.org].
    • by Anonymous Coward
      There was no known use for lasers when they were discovered....
      • The "death ray" was conceived in the 20's.

        The laser was invented in the 1960's.

        • by Sique ( 173459 )
          "Death rays" have nothing to do with Lasers, except for the fact that you can use Lasers as a very power hungry way to kill people.

          Whenever mankind discovers something, one of the first ideas is to use it to throw it at other people or at least to use it to throw other things at people, may it be feasible or not. With the discovery of X rays in the late 19th century, there was the idea to throw "rays" (of whatever kind) at people, and the "death ray" was born. But there was no actual effort to build one,

        • by john83 ( 923470 )
          The laser was [i]built[/i] in the 60s. Einstein published the theory of stimulated emission of radiation in 1917.
        • by ceoyoyo ( 59147 )

          And yet we're only just starting to turn lasers into death rays, after they've spent 40 years becoming one of the most useful and versatile fundamental technologies we've ever produced.

    • Not directly, but this experiment show results [youtube.com] that possibly undermine the Standard Model. Should that result pan out, you can be sure that there are going to be a whole lot of other new areas of research developed in consequence, some of which will certainly produce practical results.

    • by OrangeTide ( 124937 ) on Wednesday April 07, 2021 @12:14PM (#61247602) Homepage Journal

      Elementary particle research has far reaching implications for a society dependent on ever shrinking microscopic electronics.

      • Only insofar as the fundamental particle is the electron (and the photon, by extension).

        Muonics will never be as widespread because it is a short-lived particle, and the effects we are apparently seeing will never have any effect at the electron mass-energy range.
    • Someone looked into it and it seems you can make a Bitcoin miner out of the blue ones.
      I'm investing and so are all of WSB.
      Don't Miss Out.

      onceinabluemuon.com

    • Probably not. But there wasn't any practical value of understanding proton spin when they first looked at it, either.
    • by AvitarX ( 172628 ) <me@@@brandywinehundred...org> on Wednesday April 07, 2021 @12:32PM (#61247704) Journal

      Hertz had this to say when he discovered the basis of radio communication:
      “It's of no use whatsoever. This is just an experiment that proves Maestro Maxwell was right—we just have these mysterious electromagnetic waves that we cannot see with the naked eye. But they are there.”

      20 years later it allowed morse code transmission across the Altantic (at a narrow spot), 40 years later we had radio stations.

      It can take time to figure things out, even when the discovery is not immediately obvious.

    • by crunchygranola ( 1954152 ) on Wednesday April 07, 2021 @12:36PM (#61247728)

      Cosmic ray muons are being used to detect underground cavities and chambers [nature.com].

      • by cfalcon ( 779563 )

        So I'm not clear on this- do I hope that we invent the murder robots BEFORE the muon technology they can use to hunt organic rebels down in the caves, so that we can survive a bit longer, or AFTER to minimize human suffering?

    • Not to dismiss fundamental work - it's fascinating and important in its own right - but is there any technology we have or are investigating that makes use of muons?

      Most of the other responses are talking about past physics discoveries that turned into a major technological breakthrough a few decades down the line (while implicitly suggesting you're somehow unaware of this).

      So I take that to mean no, there is no, there is no technology we have or are investigating that makes use of muons. Well other than muon tomography [wikipedia.org].

      But at some point in the future it's quite plausible we'll figure out a much more important technology based on muons specifically. Though considering

    • by jythie ( 914043 )
      All depends on what you value I guess. 'practical' is neither neural nor absolute, but carries with it assumptions about what has value.
    • As others have mentioned, muon tomography can be used to study geological structure and do non-desrructive searches of shipping containers, for dxample, for fissile materials. Muon spin resonance can be used to study the magnetic structure if materials. They also do chemistry, so they can be used to understand properties of chemical compounds.

    • Comment removed based on user account deletion
    • by joe_frisch ( 1366229 ) on Wednesday April 07, 2021 @10:30PM (#61249496)
      This particular property isn't useful, but muons can travel a very long distance through matter. Cosmic ray muons have been used to map the structure of the pyarmids. There has been discussion of using muon beams to "X-ray" cargo ships without needing to unload them. Muons have been proposed as the projectiles to use in next generation particle accelerators (see "muon collider"). Muon catalyzed fusion power generation is probably not possible to make practical, but the physics isn't completely insane. My bet is that it will never work, but its not loonie tunes. So, some possibilities, but no major technological applications now. OTOH, muon science isn't very expensive. This particular measurement has no direct application I can imagine, but it does tell us something fundamental about the universe, and in the long run that often is useful in ways we don't originally imagine
    • by ceoyoyo ( 59147 )

      Well, muon catalyzed fusion would completely change the world if we could figure out a more efficient way to generate muons.

    • This work can help identify failures in your theories and measurement methods. [schlockmercenary.com]
  • This article [phys.org] claims that the most recent calculations (requiring hundreds of millions of CPU hours (whatever that means)) actually brought the calculations more in line with the observations over the past 20 years.

    • requiring hundreds of millions of CPU hours (whatever that means)

      That's the number of hours it needs to run on a CPU to do the calculation.

    • by PPH ( 736903 )

      CPU hours (whatever that means)

      Could we have that figure in potential Bitcoins mined please?

  • Cool! (Score:4, Insightful)

    by spaceyhackerlady ( 462530 ) on Wednesday April 07, 2021 @12:23PM (#61247668)

    It's one thing to confirm theories and models to high precision. It's quite another thing to look at the data, scratch one's head and think "That's funny..."

    When I read stuff like this, what they're doing at CERN, other places, it tempts me to go back to school so I can be part of it.

    ...laura

  • Objoke (Score:5, Funny)

    by nospam007 ( 722110 ) * on Wednesday April 07, 2021 @12:55PM (#61247812)

    Daughter was doing science homework. ..

    Me: "What is a cow's favorite elementary particle?"
    Her: "..."
    Me: "A Muon"
    Her: "Get out."

    • Apparently you are less magnetic than expected.

    • Daughter was doing science homework. ..

      Me: "What is a cow's favorite elementary particle?"
      Her: "..."
      Me: "A Muon"
      Her: "Get out."

      Quality dad joke. You have done your duty properly.

    • by quenda ( 644621 )

      Me: "What is a cow's favorite elementary particle?"

      Eh? Americans pronounce muon like moo-on?
        As an English-speaker, I'd have chosen a cat for the joke. Meow-on.

  • Only at the very end of the analysis did they open the envelopes containing the secret frequency—on a Zoom meeting because of COVID-19 restrictions. “Definitely there was this atmosphere of extreme tension,” says Hannah Binney, a graduate student and team member from the University of Washington, Seattle.
    • by ceoyoyo ( 59147 )

      Fortunately they found the envelopes. There was some drama and the announcement was delayed because the theorist who had the envelopes claimed to have lost them (either on the train or the dog ate them) and then wouldn't come out of his house or answer messages.

      There are some clips of the zoom unveiling:

      https://youtu.be/ZjnK5exNhZ0?t... [youtu.be]

  • The HEP community will have to do significantly better than that if they are going to obtain support for the multi-billion dollar particle accelerators that they want to build next - there is much more to physics than HEP, and funds are not infinite.
    • by cusco ( 717999 )

      They just need to get the Pentagon interested, at which point the funding never ends.

  • We've known since the early twentieth century that current theories including general relativity can predict the motions OF EXACTLY ZERO STARS IN OTHER GALAXIES. ZERO so this muon thing is news? Give me a break.... They've been wrong for fifty years about everything.
    • by k2r ( 255754 )

      They've been wrong for fifty years about everything.

      Please return your computer, it does not work since most of it is based on what “they” have been wrong about.

  • We've been measuring muons for years and they're bigger now! It's all our fault!
  • Here is an overview video [youtube.com] from FermiLab on this muon experiment.

    This BBC article says that the experiment may point to a fifth fundamental force [bbc.com].

  • This is not the first time that they have had significant discrepancies between the experimental measurement and the theoretical prediction. The last time this happened there was an error in the theory calculation where a class of Feynman diagrams was given the wrong sign and the discrepancy become much less significant with the correction.

    This result is certainly very interesting and the significance is certainly higher than before so this might be evidence of something. However, it is astoundingly hard
  • Why the Muon g-2 Results Are So Exciting!:

    https://www.youtube.com/watch?... [youtube.com]

    Muon g-2 experiment finds strong evidence for new physics:

    https://www.youtube.com/watch?... [youtube.com]

    Enjoy!

  • Except they didn't "confirm" it. That will require years more experiments. What they did was to find it was more likely to be correct than previously demonstrated.

As you will see, I told them, in no uncertain terms, to see Figure one. -- Dave "First Strike" Pare

Working...