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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?"
Maybe, but this is still surprising. Measure a grape with a metre rule, you should still be able to say 'it's between a centimetre and a centimetre and a half.' Measure it with a micrometer, and you'd expect to see a result like 'It's 1.2144 centimetres.' If the micrometer instead measured the grape at 0.7218 centimetres, well, you'd be puzzled. First of all, of course, you'd check you were doing it right. You'd examine your micrometer and make sure you were operating it correctly. You'd recheck how you measured it with the metre rule - is it zero from where the number is printed, or from the edge of the ruler, is the ruler maybe worn down at the edge?
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.
Hence the suggestion of new physics. Theoretically the muon should act like a heavy electron - interacting with the proton in just the same way, so that it can be used as a more precise probe on the size of the proton. It would be the micrometer to the electron's metre rule. If it doesn't - if the muon interacts with the proton in some unexpected way so as to throw the measure off - then we've discovered something beyond the standard model.
There are quite a few indications that there is physics beyond the standard model - heavy neutrinos, the abundance of matter over antimatter, the dark matter - and so if we can add this to the list then maybe it can help pin down just what sort of a new theory we're looking for. We've got to have something to do once the good people of Geneva finally hammer us out a Higgs, after all :-)
Real Daleks don't climb stairs - they level the building.
Which means that the theory is wrong
At best it means either the theory or the experiment is wrong, and the "wrong" can vary from mundane to really interesting, with the vast weight of probability on the side of mundane.
The structure function of the proton is not simple, and calculating it depends on QCD approximations that are even less simple. The notion that it can be characterized by a single parameter is questionable.
Muons probe a very different part of the proton structure function than electrons. Muon orbitals are much smaller than electron orbitals, so protons look even less like a point mass to them. As such it is not surprising that they would result in a significantly different value for a single parameter in a particular model of the proton, even if the experiment is not in error somehow. By far the hardest part of the structure function of nucleons to model in QCD are the tails, and that is exactly what muons will be most sensitive too.
This is how experimentalists react to anomalous results: the most probable explanation, always, is that the people doing the work screwed up. We then set out to prove how they screwed up. If we can't, we start to think about other corrections seriously.
Theorists will of course have no difficulty explaining this result, even if it later turns out to be incorrect. But even if the results are correct, they will almost certainly be accounted for by relatively insignificant tweaking of QCD estimates of the proton structure function, which is good solid science, but not the kind of great big deal that TFA seems to want to make of it.
Blasphemy is a human right. Blasphemophobia kills.
If it were grains of sand packed under the foundation of your house, it might be important.
But protons only aggregate in small groups that don't get close to each other very often. In fact, they emit a force-field that prevents it, so the size of the proton rarely if ever comes into play even in interatomic interactions.
Which brings up a rather glaring point: SLAC, Fermilab, CERN, et al have been colliding protons together for decades. You'd think they would have noted something funny in the statistics by now to indicate that their colliding objects were consistenly not colliding with the predicted probabilities. If "size" means anything, it means the most when you try to make objects bash each other head-on.
I'll be rightly surprised if the re-review of past data confirms that the 4% discrepancy was there and they simply ignored it.
And maybe I missed this yesterday when I read the story (linked from Twitter; /. is about as timely as the Wall Street Journal any more), but is the 4% volume, cross-sectional area, or radius? A 4% volume difference would be trivially easy to miss; a 4% radius error would be one hell of an oversight.
My money is on the possibility that the guys doing this new research bollixed the theory that predicts the frequency to use in their experiment. And then on the possibility that the theory they're using has never been confirmed very well. QED seems to be more concerned with photons and electrons and other less-massive particles (in fact, it doesn't say anything about mass, and if this 4% is real maybe it's a way to link gravity and GUT (the Grand Unified Theory of electromagnetism, the weak force, and the strong force...) to make the GUTE (Grand Unified Theory of Everything).
> oh well, i'm figuring that he's probably right seeing as science is just a bunch of atheistic dogma anyway...
Considering that Max Plank said:
"Eine neue wissenschaftliche Wahrheit pflegt sich nicht in der Weise durchzusetzen, daß ihre Gegner überzeugt werden und sich als belehrt erklären, sondern vielmehr dadurch, daß ihre Gegner allmählich aussterben und daß die heranwachsende Generation von vornherein mit der Wahrheit vertraut gemacht ist."
which is translated as
"A new scientific truth does not triumph by convincing its opponents and making them see the light, but rather because its opponents eventually die, and a new generation grows up that is familiar with it."
or paraphrased as the common English phrase:
"Truth never triumphs -- its opponents just die out."
"Science advances one funeral at a time."
You might be right on the dogma bit.
http://en.wikiquote.org/wiki/Max_Planck