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The Proton Just Got Smaller

inflame writes "A new paper published in Nature has said that the proton may be smaller than we previously thought. The article states 'The difference is so infinitesimal that it might defy belief that anyone, even physicists, would care. But the new measurements could mean that there is a gap in existing theories of quantum mechanics. "It's a very serious discrepancy," says Ingo Sick, a physicist at the University of Basel in Switzerland, who has tried to reconcile the finding with four decades of previous measurements. "There is really something seriously wrong someplace."' Would this indicate new physics if proven?"

13 of 289 comments (clear)

  1. Ummm... by Monkeedude1212 · · Score: 5, Insightful

    "'The difference is so infinitesimal that it might defy belief that anyone, even physicists, would care"

    Does this sentence bother any one else? Just me?

    1. Re:Ummm... by Securityemo · · Score: 4, Insightful

      Most people live in the world of senses, not the gulfs between the stars or in the mathematical models we've scrounged together to explain the eldritch abomination we call "reality". Rewrite it as "The difference is so infinitesmal that it's amazing we've come so far as to care about it." Happy?

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    2. Re:Ummm... by Anonymous Coward · · Score: 5, Insightful

      According to the article the difference is 4%. How is that small? I'm not even a physicist and that seems like a pretty huge difference to me.

    3. Re:Ummm... by Bakkster · · Score: 4, Insightful

      And thus, the reason why the % exists. It allows us to determine if a 1kg change is significant (weight of a bowling ball), insignificant (weight of the earth), of wildly significant (weight of a swallow) by giving a single digit which compares the magnitude of change to the initial value.

      In other words, 4% of a value is not an 'infinitesimal' change, even if the values of concern are generally considered to be infinitesimally small. As far as relative change, it is significant enough to care (1/25th).

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    4. Re:Ummm... by prgrmr · · Score: 4, Insightful

      It's the author's way of saying he doesn't understand physics, and that he doesn't get why anyone else would.

    5. Re:Ummm... by wurp · · Score: 5, Insightful

      Size is a somewhat ambiguous concept. I *think* what's been discovered to be off by 4% is the radius of the charge distribution. If that's true, then the volume is off by more than 12%.

      If the results of this experiment are accurate, it's a Big Deal.

    6. Re:Ummm... by mea37 · · Score: 4, Insightful

      If your lamp is emitting protons, I recommend staying away from it.

  2. Re:Previous measurement error? by thue · · Score: 5, Insightful

    > 4% sure does seem significant. But more interesting is that the measurement is thought to be much more precise because of the method of measurement.

    No. The interesting thing is that the proton size is now shown to be different than expected from theory. Which means that the theory is wrong. Which is the first step in exciting new physics.

  3. Re:Previous measurement error? by MozeeToby · · Score: 4, Insightful

    In other words, it's a "that's funny..." kind of moment.

    "The most exciting phrase to hear in science, the one that heralds new discoveries, is not 'Eureka!' (I found it!) but 'That's funny...'"
        -Asimov

  4. Re:Misleading use of absolute numbers by Anonymous Coward · · Score: 4, Insightful

    (0.8768-0.84184)/0.8768 = 0.03987

    Why didn't you say "about 4%"?

  5. Re:Ridiculous notion. by Remus+Shepherd · · Score: 4, Insightful

    No, such a size is not defined. But it could be, if it were a useful measurement. It would have to be defined in relation to the gravitational fields in the neighborhood, which would make it around the same radius as the L1 Lagrange point. Voila, we have defined a gravitational 'size', and it can even be represented graphically.

    Nothing exists unless someone has defined it; by the same token, anything can be defined in some way.

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  6. Re:Previous measurement error? by radtea · · Score: 4, Insightful

    But if all that checked out and you still had this discrepancy, you'd start to wonder if your ruler and your micrometer were really measuring the same units.

    The grape analogy is not a particularly good one. Consider instead a peach analogy. With an electron you're looking at it from 20 m away. With a muon from 10 cm away.

    At 10 cm you're going to be vastly more sensitive to the detailed structure of the peach. What at 20 m looked like it could be characterized adequately by a single radial parameter is now clearly a copmlex shape that doesn't even have a very sharp boundary, being covered with fuzz and all.

    By far the most likely explanation of this result is something slightly wrong with our understanding of the tails of the proton's structure function, not anything as deep as physics beyond the standard model.

    Massive neutrinos aside--as they require only the most minor tweak in the form of off-diagonal elements in the KM matrix--physics beyond the standard model is a bit like fusion power: we've been a few years away from detecting it for the past thirty years... It's gotta be out there somewhere, granted, but I'll be shocked if this experiment is the smoking gun.

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  7. Re:Ridiculous notion. by Ungrounded+Lightning · · Score: 5, Insightful

    The journalists who write about science often use bad, confusing, or just plain nonsensical terms. But it's almost always the journalists, and you can't really fault them for dumbing down their story to appeal to the largest group of readers.

    Sure I can. Because it breaks the story, making it false. This confuses the readers further and makes the story have less value than not running the story at all. Yes I know the REAL job of newsies is to attract eyeballs to sell to advertisers. But they pay for the eyeballs by offering information, so "dumbing down" the story until it's worse-than-useless is outright fraud. (And it's a big part of why the old news media are dying.)

    English is a very expressive language. It's usually possible to come up with wording that can get the meaning across just as clearly and just about as tersely. For instance, in this case the proton didn't just "get smaller" i.e. suddenly change size. "New measurement technique finds protons unexpectedly smaller." is my first attempt - and I'm NOT an expert in such composition. News writers are SUPPOSED to be experts in this, so there's no excuse for them.

    Slashdot had an article and discussion on this - and science popularization - a few days ago.

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