Study supports Standard Model of particle physics, excludes alternative models

Unprecedented look at electron brings us closer to understanding the universe
In this artist's representation, an electron orbits an atom's nucleus, spinning about its axis as a cloud of other subatomic particles are constantly emitted and reabsorbed. Several hypotheses predict particles, as yet undetected, would cause the cloud to appear slightly pear-shaped. ACME researchers peered at the shape with unprecedented, extreme precision. To the limits of their experiment, they saw a perfectly round sphere, implying that certain types of new particles -- if they exist at all -- have properties different from those theorists expected. Credit: Nicolle R. Fuller, National Science Foundation

In a new study, researchers at Northwestern, Harvard and Yale universities examined the shape of an electron's charge with unprecedented precision to confirm that it is perfectly spherical. A slightly squashed charge could have indicated unknown, hard-to-detect heavy particles in the electron's presence, a discovery that could have upended the global physics community.

"If we had discovered that the shape wasn't round, that would be the biggest headline in physics for the past several decades," said Gerald Gabrielse, who led the research at Northwestern. "But our finding is still just as scientifically significant because it strengthens the Standard Model of particle physics and excludes alternative models."

The study will be published Oct. 18 in the journal Nature. In addition to Gabrielse, the research was led by John Doyle, the Henry B. Silsbee Professor of Physics at Harvard, and David DeMille, professor of physics at Yale. The trio leads the National Science Foundation (NSF)-funded Advanced Cold Molecule Electron (ACME) Electric Dipole Moment Search.

The sub-standard Standard Model

A longstanding theory, the Standard Model of particle describes most of the fundamental forces and particles in the universe. The model is a mathematical picture of reality, and no laboratory experiments yet performed have contradicted it.

This lack of contradiction has been puzzling physicists for decades.

"The Standard Model as it stands cannot possibly be right because it cannot predict why the universe exists," said Gabrielse, the Board of Trustees Professor of Physics at Northwestern. "That's a pretty big loophole."

Gabrielse and his ACME colleagues have spent their careers trying to close this loophole by examining the Standard Model's predictions and then trying to confirm them through table-top experiments in the lab.

Attempting to "fix" the Standard Model, many alternative models predict that an electron's seemingly uniform sphere is actually asymmetrically squished. One such , called the Supersymmetric Model, posits that unknown, heavy subatomic particles influence the electron to alter its perfectly spherical shape—an unproven phenomenon called the "." These undiscovered, heavier particles could be responsible for some of the universe's most glaring mysteries and could possibly explain why the universe is made from matter instead of antimatter.

"Almost all of the alternative models say the electron charge may well be squished, but we just haven't looked sensitively enough," said Gabrielse, the founding director of Northwestern's new Center for Fundamental Physics. "That's why we decided to look there with a higher precision than ever realized before."

Squashing the alternative theories

The ACME team probed this question by firing a beam of cold thorium-oxide molecules into a chamber the size of a large desk. Researchers then studied the light emitted from the molecules. Twisting light would indicate an electric dipole moment. When the light did not twist, the research team concluded that the electron's shape was, in fact, round, confirming the Standard Model's prediction. No evidence of an electric dipole moment means no evidence of those hypothetical heavier particles. If these do exist at all, their properties differ from those predicted by theorists.

"Our result tells the scientific community that we need to seriously rethink some of the alternative theories," DeMille said.

In 2014, the ACME team performed the same measurement with a simpler apparatus. By using improved laser methods and different laser frequencies, the current experiment was an order of magnitude more sensitive than its predecessor.

"If an electron were the size of Earth, we could detect if the Earth's center was off by a distance a million times smaller than a human hair," Gabrielse explained. "That's how sensitive our apparatus is."

Gabrielse, DeMille, Doyle and their teams plan to keep tuning their instrument to make more and more precise measurements. Until researchers find evidence to the contrary, the electron's round shape—and the universe's mysteries—will remain.

"We know the Standard Model is wrong, but we can't seem to find where it's wrong. It's like a huge mystery novel," Gabrielse said. "We should be very careful about making assumptions that we're getting closer to solving the mystery, but I do have considerable hope that we're getting closer at this level of precision."


Explore further

Electron's shapeliness throws a curve at supersymmetry

More information: ACME Collaboration, Improved limit on the electric dipole moment of the electron, Nature (2018). DOI: 10.1038/s41586-018-0599-8
Journal information: Nature

Citation: Study supports Standard Model of particle physics, excludes alternative models (2018, October 17) retrieved 16 July 2019 from https://phys.org/news/2018-10-standard-particle-physics-excludes-alternative.html
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Oct 17, 2018
I would like to see a 'video' of an electron emitting photons and assuming lower energy orbital. THAT is the degree of precision and information gathering that they need to get to before they find some of these answers.

Until they all they can say is, "Well, it does it."

Oct 17, 2018
Video or it didn't happen?

SMH.

You need lots of photons to capture video of an event. How can you take a video of an event involving the collapse of an electron orbit and the emission of a single photon?

The investigation of the dipole moment of an electron has to be undertaken indirectly. This experiment measures the properties of photons emitted from collapsing electron shells and infers from there.

Your demand for a video is... look, just sign up for a physics class and inform yourself, mkay? And there's no need to waste the internet's bandwidth with opinions about science that aren't grounded in science.

Oct 17, 2018
LOLOL, Considering they are announcing they have 'confirmed' the spherical nature of the electron to a higher degree of certainty, but they still don't know exactly what it is, or how it does it's photon stripping trick.

I am not saying video or it did not happen, I am merely looking forward to us being ABLE to do it, maybe within my lifetime as fast as things have been going. No need to Auto-Bash anyone. Infer is just an 'educated guesstimate'.

Oct 18, 2018
"The Standard Model as it stands cannot possibly be right because it cannot predict why the universe exists," said Gabrielse, the Board of Trustees Professor of Physics at Northwestern.

Wow. What an extraordinary admission! Wow. That ontological problem is a real zinger, huh.

Oct 18, 2018
Steelwolf amazingly wrote, "I am merely looking forward to us being ABLE to do it (make videos of one-photon events), maybe within my lifetime as fast as things have been going."

Reading comprehension problem?

Oct 18, 2018
rubiks6 wrote, "Wow. What an extraordinary admission! Wow."

This is the first you're hearing about this?

The Standard Model isn't complete. Nobody in physics *ever* said it was complete.

That doesn't mean it's wrong, dude. It just means there's a lot more to the story than the model can tell us.

Oct 18, 2018
Wow! Haha. Gotta love smack-talking geeks! Even as an inference, it's interesting. If you think it's wrong, get your PhD and get in the game!

Oct 18, 2018
When they are doing work on This scale, which would have been laughed at by You and Your gang of 1 voters just days ago of someone said it could be done. Since THIS is out, I am looking forward to being able for them to make virtual vids of such things as a photon being released from an electron and the elecron's relaxing to lower energy state. They ARE using things other than photons to do this kind of imagery.

https://phys.org/...tem-menu

Laugh as you will, you are holding the dumb end of the stick if you do not think we eventually Will have such 'vids'. I remember when writing IBM in singe atoms was a huge thing. Now they just filmed an ultrafast laser photon packet in real time, I do not see where there should be difficulties in making further advances along that line.

Surely it is on their Wish List of Things to do.

Oct 18, 2018
Fast camera capture of light is a different thing entirely. The camera samples photons in a stream.

You can't use that technique to capture video of a single photon emerging as an electron orbit collapses. With one photon, you get one interaction. Run it into a sensor and it's absorbed. You don't see it until you see it; and you only see it once. You can't make a video from one frame.

But then you said 'virtual' video, and that makes me think that what you're really asking for is CGI.

CGI is great. But you do know that CGI isn't showing an actual thing, right? It's a cartoon.

Oct 18, 2018
Do you have understanding of such things as the study of X-ray diffraction patterns, electron beam microscopy etc? And how the scale has been getting finer and finer, and yet they show their schematics etc of Exactly What they have found in their studies, but yes, it is done with computer generated representations, but anymore, working at atomic level or near it, you HAVE to use different forms of inferring what is going on. For them to have enough actual information to be able to create a pure, fully realized model of EXACTLY how photons interact with electrons, both capture and release.

The rest of your tutelage does fine for a beginner, but is useless verbiage otherwise, all you are trying to do is the Capt Stumpd trick of making fun of someone and maligning them by attributing their work to, say a cartoon...Would you tell major physicists that their models were wrong since they look like cartoons? How about the chalkboard work of decades past.

Oct 18, 2018
And consider such articles as this:
https://phys.org/...ore.html

Finer and finer. Will get there yet.

Don't be a Luddite.

Oct 18, 2018
Steelwolf, don't be obtuse.

One photon = one interaction.

That's all you get.

You don't make videos of that. You can model it. You can offer CGI representations of it.

You're running into the quantum limit here. Lots of photons = you can capture videos. One photon, you can't.

Vague talk of 'advancing tech' won't help you. One photon = one interaction with a sensor. You don't get any more.

That's really, really basic physics, dude.

Oct 18, 2018
It's a strange request to ask not to video an electron in transition

You video because it's there, you video because you can as it is a test of expertise to video an electron in transition irrespective if it only one electron
Until we actually get down to the nitty-gritty of videoing it, as seeing is believing is another reason for videoing it
Modelling is not real, getting your hands dirty is real!

Oct 18, 2018
It's mind blowing that some people think you can take a video, using photons, of an electron changing energy states in an atom which in turn emits a single photon. Are you serious?

Oct 19, 2018
To be very precise, a dipole moment for the electron would mean its field is not symmetrical in 3D. It would have two lobes sticking out instead of being a sphere. This would either indicate the existence of unknown virtual particles or a composite electron.

The alternatives to the Standard Model are not panning out.

Oct 19, 2018
jimmybobber wrote, "It's mind blowing that some people think you can take a video, using photons, of an electron changing energy states in an atom which in turn emits a single photon. Are you serious?"

Our educational system is failing badly. The internet keeps us from sweeping that ugly fact under the rug - it's right out in plain sight.

Oct 19, 2018
Since Urgelt has proven himself to be a Non-science and put downs only poster, he goes to the Ignore column now. I dont mind people who can use actual data arguments, as some here I disagree with, but some JUST bash others, so on the list you go.

Oct 19, 2018
Consider that the Scanning Tunneling Electron Microscopy has been around a couple decades now, and they are finally able to take actual vids of ultrafast laser photon packets, and with x-ray diffraction they study how those x-ray PHOTONS happen to bounce off from other atoms and they can then piece together how the original material had to be based on how those photons were dispersed, we are getting to 'below photon' resolution with our data, and so representations OF that data do tend to be shown as 'representations in CGI' because That IS The Way things are Done now, like it or not.

We have gotten to the point where we ALWAYS study 'representations' once we have sorted out the data and what it means then we build the proper model. At all scales.

That IS how science works, especially in the Mainstream. So why Urgelt felt he had to single me out, I dunno, but it sure seems like a Vote Pool group with bots voting automatically and posting against specific individuals.


Oct 19, 2018
Since Urgelt has proven himself to be a Non-science and put downs only poster, he goes to the Ignore column now. I dont mind people who can use actual data arguments, as some here I disagree with, but some JUST bash others, so on the list you go.


Urgent had the science right, you were the one with the impossible fantasy.
You were not put down, your mistakes were pointed out and corrected, what else do you expect on a science site?

Oct 19, 2018
It's a strange request to ask not to video an electron in transition
You video because it's there, you video because you can as it is a test of expertise to video an electron in transition irrespective if it only one electron
Until we actually get down to the nitty-gritty of videoing it, as seeing is believing is another reason for videoing it
Modelling is not real, getting your hands dirty is real!

The difficulty is how you achieve it, possibly using the electrons dipole moment could be a way

Oct 19, 2018
jimmybobber wrote,
It's mind blowing that some people think you can take a video, using photons, of an electron changing energy states in an atom which in turn emits a single photon. Are you serious?
Our educational system is failing badly. The internet keeps us from sweeping that ugly fact under the rug - it's right out in plain sight.
There are still people who think if you could get small enough you could see atoms. It's all those movies with animations of little balls flying around. In reality it's more like soccer mixed with baseball with a million of each kind of ball in the dark. And the only hint you can get of what's going on is to catch a ball and figure where it came from. And from that you have to deduce the rules because there isn't any rulebook.

Brain surgery by telephone.

Oct 19, 2018
One of the best things I ever saw was a display at Lawrence Berkeley where they had a shape underneath a disc of wood so you couldn't see it, and you could turn the shape and the wood and shoot pinballs at it. The idea was to figure out what the shape was by looking at how the pinballs bounced back off it. This is what particle physics is.

Oct 19, 2018
@Da Schneib, Ojorf,jimmybobber, Urgelt. Although perhaps not quite relevant here, a while back I was in conversation with a EU proponent but the lines of discussion were similar. He argued that the most fundamental entity was what he called 'a unit of pure energy'.(I could extract no further mathematical/experimental information from him.) He argued that with this 'unit' we would be able (eventually) to 'see' individual photons (as well as other quantum entities). As a layman just about the only argument I thought was appropriate, that we might detect the interaction of the two but this was not the same as 'seeing' and individual photon. He was unconvinced. Perhaps those of you being more professional would have approached his argument with greater impact than I. Any advice, just in case I should encounter this again?

Oct 19, 2018
@Mimath224
Any advice, just in case I should encounter this again?
run

Oct 19, 2018
Seeing individual atoms used to be considered impossible too, let alone being able to directly manipulate them like we did over 20 years ago with writing IBM in Xenon atoms on a Nickle crystal face with a scanning tunneling electron microscope. Now we build and race Nano-cars!

Calling this impossible, when we really know nothing at all about the supposedly Superfine material that quarks and gluons, as a liquid, represent. We know it breaks down into particles of sizes we can detect, but how much action is actually going on there with further decay below the limits of our detection.

These or such energies, as when taken at too large of a scale, shows an even field. But scanning at a much finer grade finds that the flat looking football field is full of holes and ruts under the grass.

Narrowing down defect in electrons was a big thing, narrowing down to if electron was Earth the defects would be less than a millionth of a human hair!

Only a matter of time til there are vids.

Oct 20, 2018
Mimath224, your friend is positing a great big huge change to theory.

Which is great! We like ideas that are outside of the box. But theories in science are constrained: they have to fit the available evidence. And they have to *explain.*

So - the way forward for proponents of this smaller-than-photons energy is to first explain it mathematically, and then propose experiments for detecting it.

I think you'll find that none of this has been done. There are no mathematics describing this unknown smaller-than-photons energy, nor have any experiments been proposed to show it exists.

In other words, it's just unscientific blather.

If you can't explain and detect this so-called energy, then you can't design sensors to make videos with it.

Oct 20, 2018
Funny, that is what they said about atoms, or electrons, or a whole big shopping list of particles they have detected now.

We have the math and the paths laid out for a lot of it, CGI is How scientists show their data these days, so I am waiting for the based on actual data from finer than photon particles (since there is a variable minimum size due to their frequency) and so considering I have come from watching Black and White TV and Dick Tracey watches were thought to never happen, let alone a computer much smaller than a large desk, was never believed back in the '60s. Someone tell you back then what we would have today and you would be thrown out on your bum for being a lying vagabond and charlatan.

In the 60's they could not understand what it would mean to be able to be running a number of our quantum level experiments and the electron beam lithography that is taken for granted is scarcely less than magic for most people, carving with electrons?

"Impossible"

Oct 20, 2018
Finer than photon particles, Steelwolf?

Pray tell, what physics are you talking about? Where are the peer-reviewed papers proposing this theory?

Light is quantized. There is *no* theory for packets of energy smaller than photons, and no evidence for it, either.

Oct 20, 2018
@Mimath224
Any advice, just in case I should encounter this again?
run

Made me smile, Ha! Thanks.

Mimath224, your friend is positing a great big huge change to theory.

Which is great! We like ideas that are outside of the box. But theories in science are constrained: they have to fit the available evidence. And they have to *explain.*

So - the way forward for proponents of this smaller...

I think you'll find that none of this has been done...

In other words, it's just unscientific blather.

...then you can't design sensors to make videos with it.

Quite. What I did notice was it seemed more of a 'cult' where this 'unit' idea was almost held aloft and anyone else not agreeing was wrong. Thanks for the reply.

Oct 20, 2018
rustyyorkie and the other woowhooists, saw it in a comicbook! As proof-positive that whatever fraud they are selling should be unquestionably believed by the gullible,

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