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Measurement Shows the Electron's Stubborn Roundness (scientificamerican.com)
OneHundredAndTen writes: A new article in Nature reports of a new, extremely precise measurement of the electric dipole moment of the electron. The conclusion is that, within the margin of error of the measurement, the electron remains a perfect sphere. This implies that supersymmetric theories keep running out of corners to hide, that another nail is driven into their coffin, and that string theory looks less and less compelling. By lighting up the molecules with lasers, "the scientists were able to interpret how other subatomic particles alter the distribution of an electron's charge," reports Scientific American. "The symmetrical roundness of the electrons suggested that unseen particles aren't big enough to skew electrons into squashed oblong shapes, or ovals. These findings once again confirm a long-standing physics theory, known as the Standard Model, which describes how particles and forces in the universe behave."
Well, if electrons are so perfect, that only makes me wonder is Feynman's One-Electron postulate is actually true....
because it was not Feynman who postulated it?
I do not think they are claiming anything of the sort. They are saying that, as alternative theories become less likely, there is more reason to believe the Standard Model could be correct.
While it's best to say that something 'supports' a model, or is consistent with a model, scientists are human and may speak sloppily sometimes.
I'm sure the scientist understands the concept.
Does it even make sense to say an electron is "round"? Roundness to me seems to be a decidedly macroscopic idea. At those small scales, all you can really say is that there's something there that has a certain effect on the surrounding particles. But it's not like you can touch it and feel its shape. You can't even tell its exact position and speed (certainly not at the same time). So what does this roundness really mean? Its fields are perfectly symmetrical, maybe?
That's really intriguing because it allows traditional positive view to be imposed without trying to negate the p.o.v.
I wonder if that has always been the norm for physics.
What goes around comes around.
I'm trying to think of the last time an experiment to try to prove supersymmetry actually worked, and I honestly can't remember one. I do remember a solid handful over the past couple of decades that didn't pan out, though. AFAIK the best argument for supersymmetry at the moment is that someone thinks it would be awesome if things actually were arranged that way. That's pretty much it. At this point I think even string theory is more plausible than supersymmetry, and those guys are as wacky and as out-there as it gets!
I'm trying to teach myself to set people on fire with my mind... Is it hot in here?
The abstract:
"The standard model of particle physics accurately describes all particle physics measurements made so far in the laboratory. However, it is unable to answer many questions that arise from cosmological observations, such as the nature of dark matter and why matter dominates over antimatter throughout the Universe. Theories that contain particles and interactions beyond the standard model, such as models that incorporate supersymmetry, may explain these phenomena. Such particles appear in the vacuum and interact with common particles to modify their properties. For example, the existence of very massive particles whose interactions violate time-reversal symmetry, which could explain the cosmological matter–antimatter asymmetry, can give rise to an electric dipole moment along the spin axis of the electron. No electric dipole moments of fundamental particles have been observed. However, dipole moments only slightly smaller than the current experimental bounds have been predicted to arise from particles more massive than any known to exist. Here we present an improved experimental limit on the electric dipole moment of the electron, obtained by measuring the electron spin precession in a superposition of quantum states of electrons subjected to a huge intramolecular electric field. The sensitivity of our measurement is more than one order of magnitude better than any previous measurement. This result implies that a broad class of conjectured particles, if they exist and time-reversal symmetry is maximally violated, have masses that greatly exceed what can be measured directly at the Large Hadron Collider."
Now if only the Standard Model were an actual theory, instead of a list of empirical observations.
However, an electron is not just a point carrying charge. For instance it interferes with itself (so, wave nature) and it has spin (this weird property that classical point charges lack).
Every end has half a stick.
Everyone always wants to talk about the little tennis balls, but no one ever talks about the tiny little golden retrievers chasing them around.
According to quantum theory its a probability volume which is not necessarily round depending on the enviroment.
You'll just have to go with your GUT on that for now.
There are still a lot of questions on how the standard model actually works. String Theory was made to try to explain the results they see, however if you apply such theory there are aspects that are expected to happen which may be able to observe. If such aspects are found the theory is stronger, if they are absent then the theory is weaken, and perhaps may need to be altered, or even tossed out.
Real Science is all about observing and measuring. The theoretical stuff is just the first part of the process where the hypothesis are created. Then comes the part of observing and measuring where you actually see if this design will hold true.
If something is so important that you feel the need to post it on the internet... It probably isn't that important.
They are saying that, as alternative theories become less likely, there is more reason to believe the Standard Model could be correct.
The Standard Model IS correct. It has been tested and the once a theory is tested the results cannot be unproven. Now it might be that the Standard Model only works for certain conditions or it might be a subset of a more comprehensive theory. Newton's laws of motion very correctly describe large objects moving slowly but the theory was subsumed into Einstein's theory of general relativity. Newton's laws fall out of relativity under certain conditions to a high degree of accuracy and utility. We might come to a better and more comprehensive understanding of the universe but what we have already proven about the Standard Model will stand forever.
Now we know that the Standard Model is an incomplete understanding of the universe. But what it has been shown to describe it describes very accurately and that will always remain true no matter what else we learn in the future. It makes testable and correct predictions about the behavior of some bits of the universe so QED it is correct for at least those phenomena.
Now if only the Standard Model were an actual theory, instead of a list of empirical observations.
It is a theory that made testable predictions (like the Higgs boson) that were later proven to be correct via experiment. If that's not a theory then nothing is.
Ever heard of a ball of string?
(Probably a rounding error anyway)
I'm trying to think of the last time an experiment to try to prove supersymmetry actually worked
None ever have which is why we are still looking for it since it is still one of the most promising theories to explain both why the Higgs is so low in mass and what Dark Matter is. However, this result really has nothing to do with Supersymmetry. Discovering an electric dipole moment for an electron would be an example of time reversal (T) violation (as the paper says in its abstract).
Supersymmetry does not require any new T-violation. While it is possible for SUSY to include new T-violation not including it does not affect the theory in any significant way. So, while this result is very interesting it really does not have any significant implications for SUSY which far, far more constrained by the non-observation of any evidence for it at the LHC.
GOOD! Finally solve for Pi! LOL
Now if only the Standard Model were an actual theory, instead of a list of empirical observations.
There's plenty of theory behind the Standard Model. It's the core of modern physics. Observed results are explained mathematically, those models make predictions, and the predictions keep being verified. It's a very solid theory.
No one like it, because it's not elegant. There are just too many seemingly arbitrary fields and quantum numbers, and the math is nearly intractable. It's a big stinking mess that keeps successfully predicting all observations.
It's very clear now that string theory has failed at every level. It started as a quest to simplify the Standard Model, but the math is even worse, it has even more tunable parameters, and it keeps failing to predict anything. Perhaps we'd have a better alternative to the Standard Model if decades of brilliant minds weren't wasted chasing string theory nonsense.
Socialism: a lie told by totalitarians and believed by fools.
They have falsified many forms of string theory. Specifically, all forms requiring supersymmetry to squash the electron.
This shows superstrings can be falsified.
It also falsifies many other extensions to the standard model.
This is interesting as it shows you can falsify categories of solutions, which may help physics advance more rapidly.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
Scientific theories can never be proved to be correct.
They most certainly can be proven correct and are routinely. You are confused about what being falsifiable means and what being correct means. Being falsifiable means that we can state what data would cause us to declare a theory to be incorrect. It does not mean the theory cannot be proven correct. Correct in the context of a theory means it provides useful predictions. Arguments to the contrary are nothing but philosophical masturbation about whether we really know anything for certain.
To give an example I can make a prediction with effectively 100% confidence that the Earth will rotate on its axis causing the Sun to rise somewhere to the East of me tomorrow. That theory has been tested daily for millions of years and it IS correct for any meaningful definition of the word correct. I also can tell you what data would cause me to declare my sunrise theory incorrect which means the theory is falsifiable. But falsifiable does not mean incorrect. If I have overwhelming confirmatory data and no data contradicting my hypothesis then the theory is correct until such time as contradicting data is found.
They will agree with experiments, and they will make predictions that are later verified, but that doesn't imply that they are correct.
If a theory makes a prediction that is verified by experiment then the theory is correct. If the theory does not agree with experiments then it is incorrect. There is no third option. If a future theory provides a more accurate model of what is happening that does not render the previous theory incorrect insofar as it has been verified by experiment. Correct simply means it provides a verifiable prediction.
They are useful, that's all. Newton's theory of gravity is (extremely) useful, even if it is known NOT to be correct.
Newton's theory IS correct. You can use it to predict the motion of many objects to a very high degree of precision. It is just useful/correct only for certain conditions of speed and size. General relativity did not render Newton's theories false. It just showed that they are a special case of the theory of general relativity much like the theory of special relativity is just a special case of general relativity.
That is kind of a large gap to trot around stating you have determined a constraint, no?
Are you saying.. they've been stringing us along? I guess they're at the end of their rope now.
Ughh.. I won't be here all week.
Look back up at my post, now look back down, you're on the Internet. Now look back up. I'm a signature.
Perhaps we'd have a better alternative to the Standard Model if decades of brilliant minds weren't wasted chasing string theory nonsense.
I don't mind letting brilliant minds spend decades, and mere billions, trying out an alternative theory of how the universe works. It's still money better spent than the trillions that have been spent over the same period on things with little or no social value.
My braincell assigns it to Wheeler. But IANAphysicist.
Birds are not dinosaur descendants;birds are dinosaurs, for all useful meanings of "birds", "are" and "dinosaurs"
All theories are a list of empirical observations that are generalized more or less elegantly, and they all eventually break. Seems like the more elegant a theory is, the sooner it breaks.
Good question. I found this helpful: https://www.quora.com/How-does-refraction-work-If-a-photon-interacts-with-matter-it-is-absorbed-but-it-passes-through-a-transparent-material-Therefore-it-is-not-absorbed-therefore-it-does-not-interact-So-what-happens-to-slow-the-speed-of/
Strange things are afoot at the Circle-K.
Strings are 1D and this is a test in 3D - don't we expect to see an electron in 3D space? The 1D projection would be a point plus a radius ... if I recall correctly.
Maybe the equations say something else?
My God, it's Full of Source!
OUTSIDE_IP=$(dig +short my.ip @outsideip.net)
Then you can't tell if they're round, or if they're square, man.
It's the Hufflepuff Electron Uncertainty Principle.
Of course, they escape when you open the box, and it takes forever to catch them again.
-- Tigger warning: This post may contain tiggers! --
But weren't string theories just supposed to be abstract models of computation rather than a theory that subatomic particles were literally n-dimensional strings? Similarly, even if an electron is measured to be a sphere does not mean it is literally a particle.
I tried to type a response, but didn't have time.
Quantum gravity isn't a part of it. So, until someone figures that out in a way consistent with the observations made so far, the story is still evolving. The Standard Model does an amazing job of accounting for much of what we have seen. My hope is the Event Horizon Telescope project will reveal clues to this. It's likely based on its successes that the Standard Model is correct up to the edges of its predictions. It might be a minor modification to extreme cases, or it might be a major revision to how the math is done, but it's missing something.
Right, just like General Relatively broke. Oh wait.
When all you have is a hammer, every problem starts to look like a thumb.
If you want to get really pedantic, scientific theories are never "proven" to be correct, they are only shown to make correct predictions.
A distinction without a difference. Think for half a moment about what the word "correct" really means. The whole point of going out to gather evidence is to prove whether or not the predictions of the theory are correct. You make a prediction and and then you go gather evidence to see it matches your prediction. If the evidence supports the prediction then QED it is a correct model at least for the conditions tested. A theory might only work for some conditions and there might be better models but if it makes predictions that are supported by evidence then by definition it is correct.
You seem confused about the difference between the words incorrect and falsifiable. Just because a theory has a means by which it can be shown to be false (meaning it is falsifiable) does NOT mean it cannot be shown to be true. It just means that we know what it would take to prove it to be false.
No theory has ever been proven correct, and they cannot be by definition.
Common misconception. You are confused about the fact that all theories are falsifiable but that's NOT the same thing as saying that they cannot be correct. Theories that make testable predictions supported by evidence are by definition correct. Where you argument goes of the rails is that you are confusing what being falsifiable means. All scientific theories are falsifiable, meaning that you can specify the evidence required to prove them false and that you must always be willing to accept such evidence if found. That does NOT mean that such evidence necessarily exists nor does it mean that a theory cannot ever be correct.
Calling a theory correct simply means it makes testable predictions supported by evidence for the conditions tested.
Further think for just a moment about what the word "correct" means. If I make a prediction and that prediction comes to pass then by definition my prediction was correct. There is nothing else meaningful you can call it. Now maybe I just got lucky with my prediction which is why we insist that predictions of scientific theories be reproducible. But if a theory makes a testable prediction and the evidence supports that prediction (with reproducibility) then by definition that theory is correct for any meaningful definition of the word correct. A scientific theory can be (and is) simultaneously correct and falsifiable.
Yes, exactly -- wait.
It will never break on where it works now, it will just be discovered that in some special circumstances the theory no longer predicts correctly.
That said conceivably some postulates and constants on which the theory is based may change over eons -- who is to say they must remain fixed to what they now appear to have been through time -- but in practical terms it will never break for us.
And then, there are exceptions to everything, maybe this particular theory, unlike most others, will never break.