Proton-size puzzle deepens
nature.com
nature.com
(You direct your sarcasm at an easy target; it is also too easy to turn a blind eye to all the glaring omissions and gross misrepresentations - i.e., effectively, lies - purposefully made in popular texts for the sake of making the material more "accessible" for the general reader.)
The electron is inside the proton only a tiny amount of time [1] but it's enough to measure it.
[1] A better explanation should use probabilities and wave functions, but the main idea is that.
Or do you mean that the point where it can no longer be undone in principle can be considered as a cutoff for "collapse"?
Singularities makes the mathematics simpler (an approximation to the reality being worked with). Keep in mind that QM and all of its associated trappings are approximations (useful but still approximations). This is no different to the use of mathematics in any other field.
Thank you, and I wish the article had said that.
The "normal sense" for _any_ measured value, in order to be considered a reliable measurement, whether it be length, weight, or number of electrons contained within, must necessarily be established as an average of independent samples sufficient to narrow the measurement error to within the desired precision boundaries. You might as well say that you don't have a height in the normal sense because some days you stand slightly more erect than others, except that would be a misunderstanding of "normal sense" and also "height". If you can only reliably measure protons along a single particular dimensional axis, and then only on average through sampling, then you have no way of saying that it isn't actually, factually, literally a sphere, and using spherical measurement terms is reasonable. If you want, feel free to mentally prepend the word "approximately" any time you read any measurement of anything. It will always be slightly more accurate, even when just counting things.
For me, it's mainly interesting because two different fields of physics meet, nuclear physics (electron scattering) experiments, and atomic physics (spectroscopy).
Otherwise, it's the same as with all basic science. We don't know what it is "good for" until somebody figures out how to cure cancer with it.
The paper this article refers to is in particular interesting, because it finds a value not in agreement with earlier measurements of the /same/ type. The indicated 3.3 sigma shift in the Rydberg constant, one of the most exact measured quantities in existence, is a little bit worrying, but such shifts happen more often than they should.
Since you asserted an answer to the question before I managed to ask, I'm happy to subordinate my question. But I will also suggest your specific answer, cure cancer, won't work. I need to kill cells, which requires a cascade of large molecules interacting at energies on the order of a fraction of an eV, or massive amounts of high energy radiation.
I can kill cells directly with high energy radiation, however, the energies for this investigation, the hydrogen 2s-4p transition, (1,2) are trivial (486 nm is visible light). Also, radiotherapy isn't really good at interrogating cell type, the current standard for new cancer therapies (immunotherapy).
(1) http://science.sciencemag.org/content/358/6359/79
(2) https://indico.mitp.uni-mainz.de/event/14/contribution/11/ma...
Sometimes we don't know what new knowledge will enable us to do until the PhDs, engineers, and technicians get their hands on it.
People care because it's jarring that something so 'known' and basic might be different.
And yeah the cancer part was more a 'holy grail' thing. replace it with 'cures poverty' and his point still stands
If the proton and muon sizes were different, then a bunch of physicists would be chomping away at being able to replace the Standard Model and get the Nobel Prize.
As it stands, it looks like there's a question of why the old measurements were off, and that's about it.
They are different, in fact the muon is believed to be a point particle and not to have any internal structure like, for example, the proton. Nonetheless one can assign a non-zero radius to the muon in specific contexts due to its interaction with the vacuum.
Thank you for your correction.
Also, the proton is not 4% smaller. Protons are obviously whatever size they are.
The discrepancy comes from the fact there are two techniques to measure the proton size. Both experiments do their thing and then there's a way to interpret the results that would tell you the size of the proton (look up proton form factors).
However, when you do the interpretations, which depend on some theoretical calculations, you get different results. The general thinking around this result, because nobody has found any issue with the experimental results, is that there are some additional interactions that are stronger than expected that need to be accounted for (there are some unknown quantities that allow this).
One of the interactions would only affect the muonic hydrogen measurement - basically there are some different interactions between muons and protons than between electrons and protons because of the muon's mass and those might be different than originally thought.
The other is a type of interaction that could affect both normal and muonic hydrogen. This new measurement shows that the interactions that affect both has to play an important role in understanding this discrepancy. There are other measurements trying to measure this effect independently (not using hydrogen at all).
It does raise curious questions, namely what is it that we missed that lead us to believe the previous results. If the proton is indeed so much smaller, what is it that was skewing the results of the previous experiments? Perhaps this signals new physics and strange new effects.
And that may eventually lead to cold fusion and jetpacs :)
"Some researchers speculated that perhaps some previously unknown physics could make muons act differently than electrons. This would have required a revision of the standard model of particle physics, which predicts that muons and electrons should be identical in every way except for their masses — and might have pointed to the existence of yet-to-be-discovered elementary particles."
This is the reason for this precision research: it could give you the hint for where to look for new physics. This result, far from "deepening the proton-size puzzle", says that muons do not have any new physics. In other words, it's a null result.
Radius being understood to be somewhat metaphorical here.
Therefore, I posit (plausibly wrongly btw, I am not a physicist)_ that there is some measurement inaccuracy which stems from this, which is a function of this 400x size difference.