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Strong evidence found for a fifth fundamental force of nature via Muon g-2 experiment

EviLore

Expansive Ellipses
Staff Member
This could radically improve our understanding of physics and the universe. There's still so much we don't understand and can't properly account for, e.g. dark matter and dark energy, that could be explained with an expanded physics model with a fifth fundamental force.


All of the forces we experience every day can be reduced to just four categories: gravity, electromagnetism, the strong force and the weak force.
Now, physicists say they have found possible signs of a fifth fundamental force of nature.
The findings come from research carried out at a laboratory near Chicago.
The four fundamental forces govern how all the objects and particles in the Universe interact with each other.
For example, gravity makes objects fall to the ground, and heavy objects behave as if they are glued to the floor.

The UK's Science and Technology Facilities Council (STFC) said the result "provides strong evidence for the existence of an undiscovered sub-atomic particle or new force".
But the results from the Muon g-2 experiment don't add up to a conclusive discovery yet.

There is currently a one in a 40,000 chance that the result could be a statistical fluke - equating to a statistical level of confidence described as 4.1 sigma.
A level of 5 sigma, or a one in 3.5 million chance of the observation being a coincidence, is needed to claim a discovery.
Prof Mark Lancaster, who is the UK lead for the experiment, told BBC News: "We have found the interaction of muons are not in agreement with the Standard Model [the current widely-accepted theory to explain how the building blocks of the Universe behave]."
The University of Manchester researcher added: "Clearly, this is very exciting because it potentially points to a future with new laws of physics, new particles and a new force which we have not seen to date."

The finding is the latest in a string of promising results from particle physics experiments in the US, Japan, and most recently from the Large Hadron Collider on the Swiss-French border.
Prof Ben Allanach, from Cambridge University, who was not involved with the latest effort, said: "My Spidey sense is tingling and telling me that this is going to be real.

"I have been looking all my career for forces and particles beyond what we know already, and this is it. This is the moment that I have been waiting for and I'm not getting a lot of sleep because I'm too excited."
The experiment, based at the Fermi National Accelerator Laboratory (Fermilab) in Batavia, Illinois, searches for signs of new phenomena in physics by studying the behaviour of sub-atomic particles called muons.
There are building blocks of our world that are even smaller than the atom. Some of these sub-atomic particles are made up of even smaller constituents, while others can't be broken down into anything else (fundamental particles).
The muon is one of these fundamental particles; it's similar to the electron, but more than 200 times heavier.

The Muon g-2 experiment involves sending the particles around a 14-metre ring and then applying a magnetic field. Under the current laws of physics, encoded in the Standard Model, this should make the muons wobble at a certain rate.
Instead, the scientists found that muons wobbled at a faster rate than expected. This might be caused by a force of nature that's completely new to science.

No one yet knows what this potential new force does, other than influence muon particles.
Theoretical physicists believe that it might also be associated with an as-yet undiscovered sub-atomic particle. There is more than one concept for what this hypothetical particle might be. One is called a leptoquark, another is the Z' boson (Z-prime boson).
Last month, physicists working at the LHCb experiment at the Large Hadron Collider described results that could point to a new particle and force.
Dr Mitesh Patel, from Imperial College London, who was involved with that project, said: "The race is really on now to try and get one of these experiments to really get the proof that this really is something new. That will take more data and more measurements and hopefully show evidence that these effects are real."
Prof Allanach has given the possible fifth force various names in his theoretical models. Among them are the "flavour force", the "third family hyperforce" and - most prosaic of all - "B minus L2".

In addition to the more familiar forces of gravity and electromagnetism (which is responsible for electricity and magnetism), the strong and weak forces govern the behaviour of sub-atomic particles.
A fifth fundamental force might help explain some of the big puzzles about the Universe that have exercised scientists in recent decades.
For example, the observation that the expansion of the Universe was speeding up was attributed to a mysterious phenomenon known as dark energy. But some researchers have previously suggested it could be evidence of a fifth force.
Dr Maggie Aderin-Pocock, co-presenter of the BBC's Sky at Night programme, told BBC News: "It is quite mind boggling. It has the potential to turn physics on its head. We have a number of mysteries that remain unsolved. And this could give us the key answers to solve these mysteries."

 
Good Burger Reading GIF


Wild stuff!
 
I thought they already managed to observe the Higgs Boson (god particle) back in 2012. I'm not sure I understand the difference here. I guess similar thypotheses and first one who gets there type thing.
 

EviLore

Expansive Ellipses
Staff Member
Wild stuff!
Basically, up to this point, we've observed four fundamental forces in the universe:

Electromagnetic force (electricity, magnetism, light/radiation)
Gravity
Strong force (binds nuclei of atoms together, involved in nuclear fusion)
Weak force (responsible for radioactive decay, involved in nuclear fission)

Our understanding of the universe, galaxies, solar systems, stars, the Earth, atoms, and subatomic particles is all based on these physical forces.

But, we clearly have an incomplete picture, as dark matter and dark energy, among other things, demonstrate.

This Muon g-2 experiment has demonstrated the existence of a previously unknown fifth force. This is looking like the biggest physics breakthrough in decades.

Understanding electromagnetic forces and mechanics brought about the industrial revolution. Understanding nuclear forces brought forth the atomic age. We don't have any idea what this discovery could mean, yet, but it's probably a Big Deal.
 

Ballistik

Member
I thought they already managed to observe the Higgs Boson (god particle) back in 2012. I'm not sure I understand the difference here. I guess similar thypotheses and first one who gets there type thing.

From what I read in the article, the Muon g-2 experiment is about these particles called muons, they run them through an experiment where they apply a magnetic field to them. Using the Standard Model and making all the calculations, they expect the particles to wobble at a certain rate when observed. When they measure it, they actually appear faster. So their coming to an understanding that there's another force in the universe acting on the muon particles... something unaccounted for in their measurement.
 
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OmegaSupreme

advanced basic bitch
Basically, up to this point, we've observed four fundamental forces in the universe:

Electromagnetic force (electricity, magnetism, light/radiation)
Gravity
Strong force (binds nuclei of atoms together, involved in nuclear fusion)
Weak force (responsible for radioactive decay, involved in nuclear fission)

Our understanding of the universe, galaxies, solar systems, stars, the Earth, atoms, and subatomic particles is all based on these physical forces.

But, we clearly have an incomplete picture, as dark matter and dark energy, among other things, demonstrate.

This Muon g-2 experiment has demonstrated the existence of a previously unknown fifth force. This is looking like the biggest physics breakthrough in decades.

Understanding electromagnetic forces and mechanics brought about the industrial revolution. Understanding nuclear forces brought forth the atomic age. We don't have any idea what this discovery could mean, yet, but it's probably a Big Deal.
Thanks for the rundown. I'm exhausted and should be sleeping so this helped out a lot. Lots of cool breakthroughs lately.
 

EviLore

Expansive Ellipses
Staff Member
I thought they already managed to observe the Higgs Boson (god particle) back in 2012. I'm not sure I understand the difference here. I guess similar thypotheses and first one who gets there type thing.
The observation of the Higgs boson confirmed our existing theoretical model of particle physics. We had been looking to confirm it for decades, and the Large Hadron Collider was built in part to do so.

This is the discovery of a new fundamental force that was previously unknown.
 
The observation of the Higgs boson confirmed our existing theoretical model of particle physics. We had been looking to confirm it for decades, and the Large Hadron Collider was built in part to do so.

This is the discovery of a new fundamental force that was previously unknown.

I had thought the Higgs Boson was the standard model influencing the sub atomic. In this article it even seems to state 3 hypotheses competing for the same sub atomic particle force explanation. It seems the muon hypothesis is a non standard model and the Z Prime Boson is a child of the Higgs Boson standard model.

There is more than one concept for what this hypothetical particle might be. One is called a leptoquark, another is the Z' boson (Z-prime boson).

Maybe I'm just confused. I haven't studied physics for over 25 years.
 

EviLore

Expansive Ellipses
Staff Member
I had thought the Higgs Boson was the standard model influencing the sub atomic. In this article it even seems to state 3 hypotheses competing for the same sub atomic particle force explanation. It seems the muon hypothesis is a non standard model and the Z Prime Boson is a child of the Higgs Boson standard model.



Maybe I'm just confused. I haven't studied physics for over 25 years.
Particle physics :lollipop_downcast_sweat:
 
Basically, up to this point, we've observed four fundamental forces in the universe:

Electromagnetic force (electricity, magnetism, light/radiation)
Gravity
Strong force (binds nuclei of atoms together, involved in nuclear fusion)
Weak force (responsible for radioactive decay, involved in nuclear fission)

Our understanding of the universe, galaxies, solar systems, stars, the Earth, atoms, and subatomic particles is all based on these physical forces.

But, we clearly have an incomplete picture, as dark matter and dark energy, among other things, demonstrate.

This Muon g-2 experiment has demonstrated the existence of a previously unknown fifth force. This is looking like the biggest physics breakthrough in decades.

Understanding electromagnetic forces and mechanics brought about the industrial revolution. Understanding nuclear forces brought forth the atomic age. We don't have any idea what this discovery could mean, yet, but it's probably a Big Deal.
Yep. If this 5th force will be able to explain Dark Energy and Dark Matter. Wooo Boy !!
 

ManaByte

Gold Member
Basically, up to this point, we've observed four fundamental forces in the universe:

Electromagnetic force (electricity, magnetism, light/radiation)
Gravity
Strong force (binds nuclei of atoms together, involved in nuclear fusion)
Weak force (responsible for radioactive decay, involved in nuclear fission)

Our understanding of the universe, galaxies, solar systems, stars, the Earth, atoms, and subatomic particles is all based on these physical forces.

But, we clearly have an incomplete picture, as dark matter and dark energy, among other things, demonstrate.

This Muon g-2 experiment has demonstrated the existence of a previously unknown fifth force. This is looking like the biggest physics breakthrough in decades.

Understanding electromagnetic forces and mechanics brought about the industrial revolution. Understanding nuclear forces brought forth the atomic age. We don't have any idea what this discovery could mean, yet, but it's probably a Big Deal.
Working Star Trek GIF by University of Alaska Fairbanks
 

EviLore

Expansive Ellipses
Staff Member
Any idea on how frequent experiments come in at or around 4.1 sigma? I assume this is pretty rare.
Muons are at a similar scale to electrons and the measurements involved with this Muon g-2 experiment are very tiny. Particle physics requires extreme p-values for discoveries because of the roles of chance involved at that scale--as opposed to, say, testing whether a COVID vaccine is effective, which is a much more straightforward observation. The last significant discovery for particle physics at that 5-sigma threshold was the Higgs boson in 2012, I think. To my knowledge, they're looking to get to 5-sigma on this by next year.
 

EviLore

Expansive Ellipses
Staff Member
Yep. If this 5th force will be able to explain Dark Energy and Dark Matter. Wooo Boy !!
I'm listening to this interview with Dan Hooper, physicist at Fermilab (where this Muon experiment was conducted) and author of a book on the questions of dark matter and dark energy. He was asked a question about the implications for this news re: explaining dark matter (timecoded to question):





He thinks that, if confirmed at 5-sigma confidence, this will lead to a new standard model of physics, and may indeed explain and account for dark matter, either via a new fundamental force or via a new particle, possibly from the as-yet-unproven supersymmetry extension of particle physics.
 

CloudNull

Banned
I'm listening to this interview with Dan Hooper, physicist at Fermilab (where this Muon experiment was conducted) and author of a book on the questions of dark matter and dark energy. He was asked a question about the implications for this news re: explaining dark matter (timecoded to question):





He thinks that, if confirmed at 5-sigma confidence, this will lead to a new standard model of physics, and may indeed explain and account for dark matter, either via a new fundamental force or via a new particle, possibly from the as-yet-unproven supersymmetry extension of particle physics.

You just sent me down a rabbit hole of learning about supersymmetry... wild stuff.

The fact that we still know so little about gravity when it comes to particle physics blows my mind. It will be great to see if this leads to filling in the gaps and it will be interesting to see how it changes the standard model.
 
The g-factor derived from the standard model measures how strongly particles align with a magnetic field. Similar to how a compass-needle would align with the magnetic north pole.
Quantum theory predicted a g-factor of 2 for electrons. Physical experiments have confirmed a g-factor of 2.001159652181643. Yes, those are 15 decimals, that is how insanely precise those experiments really are.

The name of the experiment references this number "g minus 2", i.e. that one parts in a billion left-over bit.

When the same theory is applied to muons, the g-factor is way off. Muons are basically the same as electrons, yet the standard model cannot predict its correct g-factor. Muons are 200 times larger than electrons, which means that their likelihood of interacting with other quantum particles is about 40.000 times more likely. Even when accounting for this, the numbers are off. This leads scientists to believe in the existence of another yet to be discovered particle.

In essence, the muon g-2 experiment almost confirmed (1 in a 100.000 probability) the existence of a such a new particle. These experiments are mindbogglingly precise, so there's still a slight possibility that the current results might just be a statistical fluke.
So far it's looking good though, but more independent experiments need to be made.
 
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jufonuk

not tag worthy
This could radically improve our understanding of physics and the universe. There's still so much we don't understand and can't properly account for, e.g. dark matter and dark energy, that could be explained with an expanded physics model with a fifth fundamental force.





What a Time to be alive, no seriously. This could be game changing.
 
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I wonder if this is like the weak force to electroweak and is a particle-level or energy-dependent aspect of "gravity"? It can't be a macro-level force - it would have been seen by now in physics.

I hope it's a completely separate force, though (or at least as separate as the others are in the current state of the universe). It would be awesome if there was another property like mass, charge, and color that was behind the scenes influencing the low level.
 
I'm listening to this interview with Dan Hooper, physicist at Fermilab (where this Muon experiment was conducted) and author of a book on the questions of dark matter and dark energy. He was asked a question about the implications for this news re: explaining dark matter (timecoded to question):





He thinks that, if confirmed at 5-sigma confidence, this will lead to a new standard model of physics, and may indeed explain and account for dark matter, either via a new fundamental force or via a new particle, possibly from the as-yet-unproven supersymmetry extension of particle physics.

sweet_jesus.gif
 
Basically

I'm with you.

Electromagnetic force (electricity, magnetism, light/radiation)

Gravity
Strong force (binds nuclei of atoms together, involved in nuclear fusion)
Weak force (responsible for radioactive decay, involved in nuclear fission)

Our understanding of the universe, galaxies, solar systems, stars, the Earth, atoms, and subatomic particles is all based on these physical forces.

But, we clearly have an incomplete picture, as dark matter and dark energy, among other things, demonstrate.

This Muon g-2 experiment has demonstrated the existence of a previously unknown fifth force. This is looking like the biggest physics breakthrough in decades.

Understanding electromagnetic forces and mechanics brought about the industrial revolution. Understanding nuclear forces brought forth the atomic age. We don't have any idea what this discovery could mean, yet, but it's probably a Big Deal.

uhhh...
 
So, does this put "hidden variables" back on the table?

I'm not a quantum guy, but I know Bell's theorem deals with the hidden variable problem:


Consequently, the only way that hidden variables could explain the predictions of quantum physics is if they are "nonlocal", somehow associated with both halves of the pair and able to carry influences instantly between them no matter how widely the two halves are separated. As Bell wrote later, "If [a hidden-variable theory] is local it will not agree with quantum mechanics, and if it agrees with quantum mechanics it will not be local."

It looks like it constrains the kind of hidden variables which can exist. The logic in "If [a hidden-variable theory] is local it will not agree with quantum mechanics, and if it agrees with quantum mechanics it will not be local." is overstated because it is just "statement+contrapostive".

The applicable logic is "If there is a hidden variable which agrees with quantum mechanics, then it's influence is not local." If I'm taking the definition of "local" right, if this experiment does demonstrate a fifth force that agrees with quantum mechanics, then this force is able to exert influence instantly across space. All information transfer (translation of particles, application of force) in the universe is limited by the speed of light - particles can't go faster than light speed, gravity propagates at light speed, the propagation of electromagnetism (and presumeably the weak force because they are linked) IS light so it obviously propagates at light speed. I'm assuming the strong force propagates at light speed as well, though I don't know that for certain. So it sounds like this new force can propagate faster than light if Bell's theorem holds.
 
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Bogey

Banned
The g-factor derived from the standard model measures how strongly particles align with a magnetic field. Similar to how a compass-needle would align with the magnetic north pole.
Quantum theory predicted a g-factor of 2 for electrons. Physical experiments have confirmed a g-factor of 2.001159652181643. Yes, those are 15 decimals, that is how insanely precise those experiments really are.

The name of the experiment references this number "g minus 2", i.e. that one parts in a billion left-over bit.

When the same theory is applied to muons, the g-factor is way off. Muons are basically the same as electrons, yet the standard model cannot predict its correct g-factor. Muons are 200 times larger than electrons, which means that their likelihood of interacting with other quantum particles is about 40.000 times more likely. Even when accounting for this, the numbers are off. This leads scientists to believe in the existence of another yet to be discovered particle.

In essence, the muon g-2 experiment almost confirmed (1 in a 100.000 probability) the existence of a such a new particle. These experiments are mindbogglingly precise, so there's still a slight possibility that the current results might just be a statistical fluke.
So far it's looking good though, but more independent experiments need to be made.

I watched the same video.

And while their explanation somewhat made sense to me, the conclusion sounded like "... And that's why a new particle might be at play here".

What I didn't get is how they got from "new particle" to "new force of nature"!?
 

DeepEnigma

Gold Member
Basically, up to this point, we've observed four fundamental forces in the universe:

Electromagnetic force (electricity, magnetism, light/radiation)
Gravity
Strong force (binds nuclei of atoms together, involved in nuclear fusion)
Weak force (responsible for radioactive decay, involved in nuclear fission)

Our understanding of the universe, galaxies, solar systems, stars, the Earth, atoms, and subatomic particles is all based on these physical forces.

But, we clearly have an incomplete picture, as dark matter and dark energy, among other things, demonstrate.

This Muon g-2 experiment has demonstrated the existence of a previously unknown fifth force. This is looking like the biggest physics breakthrough in decades.

Understanding electromagnetic forces and mechanics brought about the industrial revolution. Understanding nuclear forces brought forth the atomic age. We don't have any idea what this discovery could mean, yet, but it's probably a Big Deal.
darth vader GIF
 

CloudNull

Banned
The g-factor derived from the standard model measures how strongly particles align with a magnetic field. Similar to how a compass-needle would align with the magnetic north pole.
Quantum theory predicted a g-factor of 2 for electrons. Physical experiments have confirmed a g-factor of 2.001159652181643. Yes, those are 15 decimals, that is how insanely precise those experiments really are.

The name of the experiment references this number "g minus 2", i.e. that one parts in a billion left-over bit.

When the same theory is applied to muons, the g-factor is way off. Muons are basically the same as electrons, yet the standard model cannot predict its correct g-factor. Muons are 200 times larger than electrons, which means that their likelihood of interacting with other quantum particles is about 40.000 times more likely. Even when accounting for this, the numbers are off. This leads scientists to believe in the existence of another yet to be discovered particle.

In essence, the muon g-2 experiment almost confirmed (1 in a 100.000 probability) the existence of a such a new particle. These experiments are mindbogglingly precise, so there's still a slight possibility that the current results might just be a statistical fluke.
So far it's looking good though, but more independent experiments need to be made.
This is a fantastic summarization.

Its great to potentially be finding the answer to physics issues that we have known about for years. The world burns on one end while major scientific breakthroughs happen on the other. Truly is exciting times.
 

Toons

Member
If something comes of this it'll be fascinating but will take a long time to see any actual ramifications of it. Oh well, I'm here for the ride regardless
 
I'm not a quantum guy, but I know Bell's theorem deals with the hidden variable problem:




It looks like it constrains the kind of hidden variables which can exist. The logic in "If [a hidden-variable theory] is local it will not agree with quantum mechanics, and if it agrees with quantum mechanics it will not be local." is overstated because it is just "statement+contrapostive".

The applicable logic is "If there is a hidden variable which agrees with quantum mechanics, then it's influence is not local." If I'm taking the definition of "local" right, if this experiment does demonstrate a fifth force that agrees with quantum mechanics, then this force is able to exert influence instantly across space. All information transfer (translation of particles, application of force) in the universe is limited by the speed of light - particles can't go faster than light speed, gravity propagates at light speed, the propagation of electromagnetism (and presumeably the weak force because they are linked) IS light so it obviously propagates at light speed. I'm assuming the strong force propagates at light speed as well, though I don't know that for certain. So it sounds like this new force can propagate faster than light if Bell's theorem holds.

This isn't quite right. Bell's Inequality is just another quantum no-go theory which, in this case, puts limits on local realism in reality. Locality is a tricky thing in physics at small scales and as you scale up your particle number. I wouldn't be surprised to see a breakthrough in this area in the next decade or two that extends past current holography, which is already an impressive field if you consider AdS/CFT correspondence.

I haven't read up on this extensively yet, but what EviLore posted is orthogonal to QM and Bell's Inequality I'd assume. It wouldn't impact the speed of light and it's importance as a cosmic speed-limit on information transfer.

It would likely be another force that is only applicable over extreme scales in terms of size and strength -- which is why we haven't discovered it yet if it exists. Very interesting though!

I'll be back later if I didn't explain well enough or whatever. Take care.
 
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