Is the weak nuclear force really a force?
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- Опубликовано: 31 май 2024
- The weak nuclear force is often said to be the cause of some forms of radioactivity, but is it a force in the traditional sense? In this video, Fermilab's Dr. Don gives us a deeper dive into how the weak force works. It's a mind-blowing interaction in the subatomic world.
Fermilab physics 101:
www.fnal.gov/pub/science/part...
Fermilab home page:
fnal.gov 
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The "deeper dives" into these subjects are always the most fascinating. I'd like to see more.
i second that wholeheartedly .
@@causewaykayak I vote Aye on this motion
It's funny how this 'no one wants technicalities on teh internets' idea still exists. Nothing is too technical - more or less every level can be explained in an interesting and entertaining form
Very true
@@simonebest6013 Simone (?) you have Split an Infinitive which is a class of Sin entirely in its own category. To pay for this gross atrocity - when the sun vanishes instantly in compliance with your wishes - You wont be allowed to witness the event 👇🏿 so never be quite sure .... sorry about that but it's your own fault.
Honestly, I would genuinely appreciate a longer video going more in-depth about the Weak Force.
PBS spacetime has a few good videos on the topic, although they are not easy to grasp and they give you an idea on why this stuff is so notoriously difficult to understand properly.
I second that.
this is great! I'll be referencing this video when I need to cut corners with the weak force from now on
Please make a video related to weak force in detail
Onya Anton👍
Petrov!❤
Hello wonderful person 🙋♂️
@@okman9684Haha only Anton thinks we are wonderful people.
Now I am extremely intrigued to know how the electroweak force was discovered and what the combination of the two forces as actually the same force means when talking about particle interactions.
It’s a wild picture, much weirder than you might initially think. I’d love to see a video covering it.
Make a video on quantum physics pls vote.... 😢
@@moocowpong1
PBS Space-time Electroweak theory video:
ruclips.net/video/qKVpknSKgE0/видео.html
+1 🙂
It means that at extremely high energies, there is only one electroweak force, not separate electrical, magnetic, and weak forces. Which I guess many not be very helpful, but that's it.
Thanks Don, you are an expert who can explain. Very rare on the internet.
Very rare on Earth
rare but strong? ;)
For those still puzzled by the concept of mass uncertainty, the Heisenberg uncertainty principle states that the duration in time and uncertainty in a particle's energy are connected through a constant, ΔE Δt ≥ ħ/2. Additionally, as Einstein demonstrated with his famous equation E=mc², mass can be understood as a measurement of energy. Consequently, mass also carries inherent uncertainty.
This implies that the shorter a particle's lifespan, the wider the spread of its probability function becomes. Considering the weak boson particles, which decay rapidly, their mass also becomes probabilistic. Interestingly, even photons, conventionally regarded as massless, can exhibit mass if they engage in an interaction involving highly energetic photons that decay into a pair of matter and antimatter electrons. Thus, the transient photon, although typically short-lived, may acquire mass due to the inherent uncertainty.
Thanks! Extremely convenient to add imo
Sounds right, i always thought that there was more to the photon that met the eye. ! hahahhaaa
A photon is massless when it comes to special relativity but it has energy when it interacts with particles and, therefore, acts as a massed object
@@LadyAnuB They act like particles with momentum, not mass. (p=mv is only a close approximation of momentum when dealing with very massive objects moving at very slow speeds (compared to the speed of light).
@@StarkRG This is something that I need to brush up on considering this was ~30 years ago for me
Less than ten minutes and I learned more than hours of lectures. Thank you for these Dr. Lincoln
Weak interactions tend to take a long time because of what you said...except for the top quark, which decays so rapidly that it doesn't have time to form hadrons. The reason for this is that has more mass than two W and/or Z particles in their normal mass range so it doesn't have to rely on the low probability of producing them that the lower-mass quarks do. It does so directly, and since the speed of a force depends on the mass of the force boson, the reaction is far faster than the strong interaction.
There is also at least one quark produced during the decay, usually but not always a bottom quark.
That makes a lot of sense actually. Thank you
Dr. Don, more "deep dives" would be great. I always learn something from your videos. The production and the presentation are excellent. Thanks so much for the magnificent content all these years. You are appreciated!
The other weak force you don't hear physicist's mention is the Bar force. It's supposed to keep me from picking up a candy bar when I'm trying to lose weight. It rarely shows up but when it does, it has to be pretty strong to work.
They also have yet to explain why skittles occur in a short burst of high frequency. There must be more than the weak force at play here... and how do they account for all the red ones?
Now that was a very strong elucidation of the weak force Dr. Don! Well done! 👍👍💥💥
This was a really interesting video. The notion that a lightweight W boson is possible, but rare, and is required for the interaction is just plain amazing.
Yes, more of these deeper dives please. This is excellent, so clear I could happily use it with my son.
I can't emphasize enough how I love Dr. Don charismatic, very well didactic videos. I've been following for years
Fantastic Quick Video. This cleared up several questions I've had for years, but never bothered to deep-dive myself. Thank you.
Yes, I'd love to watch/listen to a deeper dive on the Weak Force, please! Thanks for the video.
On the topic of is-it-a-force... The results of Pauli's exclusion principle sure looks like a force, as it counteracts the ability of half spin particles to be in the same state, i.e. to bunch up together. I would really appreciate a video explaining the distinction in that case. Thanks.
Pauli exclusion is not pushing anything. E.g. due to it, a neutron inside neutron star can't decay, because there is "no available electron states" for resulting electron to exist in. But neutron feels no force.
@@denysvlasenko1865 When you draw a free body diagram of a weight on a table, you have the gravitational force pushing downwards and the normal force pushing upwards. The normal force is caused by Pauli exclusion.
Don, thank you so much! I've been asking this question for such a long time and couldn't really get a straight answer! Now I have one! Great topic and, as always, great video!
Imagine this guy as a lecturer! He would be Feynman-level awesome! Actually a full lecture series wouldn't be a bad idea, if you can ever spare the time!
That would be great! Full lecture series please
He's done at least one series for the Great Courses / Teaching Company / Wondrium
This man is completely awesome. And Femilab producing these instructional videos for the general public, solid information on physics that would take us years to learn, is also awesome. Thanks all!! 🏆🏆🏆
Agreed. It is a hands-down the best scientific channel on RUclips. Or at very least the best when it comes to physics.
Top tier physics channel for sure
Try Lecture series The Theory of Everything on Great Courses signature collection!
Interesting explanation of the weak force, especially describing the W bosons with the required energy as rare. From what I have been told before, the reason the weak force is considered weak is due to its lack of range, and that's due to the boson force carries having so much mass that their lifetimes are short as per the uncertainty principle. Are these two explanations equivalent?
yes, but the latter one is passé. see: Breit Wigner Distribution.
Thank you for this enlightening info ;)
First time I've learnt something concrete about the weak nuclear force, rather than that, "It's responsible for some forms of radioactivity..." fob-off I normally read. Great, and good to have the fob-off explicitly acknowledged!
YES! Thanks a million, Don, I understood this on a whole new level now.
I love this kind of "deep-dive" video; it's short, to the point and understandable. 🏆 PERFECT!
Thanks for explaining this. Can you elaborate further on how elementary particles can change? Does this imply that maybe they are not elementary? Even just changing properties without changing to a whole different kind of particle seems to suggest some underlying structure.
That is an open question in particle physics. Personally, I think your conjecture is likely to be true, however there is zero direct evidence supporting it. So, wait and see.
no structure, but underlying symmetry is required. Here it's called weak isospin (because it's weak, and has the same math as spin). The same way an electron can flip it's spin by exchanging a photon, a quark can flip its` flavor by exchanging a weak boson.
@polanve ultimately it’s because in electroweak theory, an electron and a neutrino are two sides of the same coin; they’re both part of an “isospin doublet”, and likewise for two different quarks. But we see electroweak theory through the lens of broken symmetry. What seems like a fundamental change to the nature of the particle is like the particle rotating so that a different face of it is visible through that lens.
So, you may have seen Feynman diagrams where there are vertices where there’s a wavy line representing a photon, and two straight lines representing an electron, meeting at a point,
And depending on how these are arranged, this can represent any of:
1) an electron absorbing a photon, and then carrying on its way
2) an electron emitting a photon, and then carrying on its way
3) either of the 2 above things except replace “electron” with “positron”
4) a photon decaying into an electron and a positron
5) an electron and positron annihilating and producing a photon.
This kind of interaction has 3 parts to it, an electron part, the flipped-around version of the electron part[1], and the photon part.
Note that there’s the photon part, where the photon is the force carrying particle, a boson,
and then there’s a pair of electron parts.
To have an interaction that gives a change in identity, you would have it so that the 3 lines meeting at the point, are of three different kinds. One of the 3 kinds would be the W or Z boson, and the other two lines would be the two different flavors of particles that things are going between.
(But the interaction has to be compatible with the symmetries, so there are some charges that need to be conserved by this interaction. So any kind of charge that the two flavors might differ in, has to be matched/carried by the charges of the boson.
Err.. I said the interaction “has to be” compatible with the symmetries, but maybe I should just say “is compatible with the symmetries”.)
[1]: “flipped around” in that either one is the input “electron goes into interaction” and one is output “electron comes out of interaction”, or one is electron and one is positron (i.e. anti-electron)
the “flipped around” iirc corresponds to the Hermitian conjugate of some operator, which is pretty much like taking the complex-conjugate transpose of a matrix.
You should look into quantum field theory.
Particles are waves or peaks of energy in a field (universe-spanning medium that holds and exchanges energy with fields it overlaps with, and has fundamental symmetries (rules of how it operates explainable by different kinds of math like points vectors tensors etc)
Every electron acts like an electron because it is just a small part of the same "object".
The weak force bosons involve the photon field, and the higgs field.
Before a certain symmetry was broken (by not having enough energy to operate that way), the 3 other higgs particles overlapped with the 3 other photons and became the weak bosons. But back during the electroweak unification era there were 2 chargless higgs, 2 charged higgs, and 2 chargless photons 2 charged photons.
What a classical explanation of a quantum phenomenon. I'm going to use that now, thanks!
You think I could run with it and talk about the weak force as though I'm pulling things out of the bag and tossing it again with less contents? Or does that analogy break down?
This was a far better way to learn about it than either simply reading about it or trying to make sense of static drawings. I certainly appreciate it, it helps me grasp the concept better.
No one explained weak force like you did. Thank you
Could you please make a video explaining how the time dilation due to the difference in gravitation between the surface and the center of star affects the behavior and lifecycle of the star?
Can you explain why the weak force is “related” to the electromagnetic?
Great vid as always! Keep up the good work guys!
You ahould look into electroweak unification era. Its on Wikipedia
W+, w-, and z boson used to be split up into 3 extra higgs particles and 3 extra photons. When the symmetry broke they "fell into" eachother and became the weak bosons. What used to be 1 force with more particles became 2 forces with less particles
@@orbismworldbuilding8428 does this imply that the laws of physics were mutable at the time of the big bang and had to "harden" into the more stable laws we see now?
@@aresh004 the laws of physics just work like the laws of physics at that energy level. If we put enough energy into someparticles they would act like they used to before, during, and shortlely after the big bang.
Its possible that when we lose enough energy, physics will change again and act differently at those energy levels.
If the false vacuum theory is true, a false vacuum decay would be an event that results in a significant change in physics.
@@aresh004 not really
Think of a phase transition from solid to liquid to gas, gas always acts like gas under those conditions (certain ranges of pressure and temperature) and physics is the same way, with laws and particle interactions changing depending on the phase of the universe.
I know I’m late to this video and to your channel, but wanted to confirm that deep dives like this are very welcome.
The heavy sack and boat analogy made so much sense on recoil 🙌🏼
The funny thing about the strong force is that it becomes weak at high energy levels.
And the weak force is stronger than the strong force at those energies.
Good to know
How can a quark with a mass less than a proton emit a W+ boson with a mass 82 times greater than proton's mass?
Because the mass of a W+ boson isn't always 80 GeV; there's a diminishingly small but non-zero probability of one being created with a significantly lower mass (~1 MeV or so for weak force interactions to occur)
As far as I understand it's a question of two factors: (1) mass is nothing but energy, (2) quantum fluctuations (probability) which beat logic (unless you're strongly quantum-minded, I guess).
What trainjumper said
Virtual particles can have any mass. The W boson in interactions are virtual particles.
@@tonywells6990 it means virtual particles are not physically real, its producing phantom energy?
Please keep the deep dives coming, and sharpen more corners!
Prof. Lincoln, an off-topic argument: in a next video can you explain the problem of the self-energy of the electron and its solution by introducing what is known as mass renormalization?
I miss your mustache
It was only held together by weak forces, and I'm sure it will recur from its own natural processes, given enough time. ⚛️😂
The moustache had it's own gravitational field that hindered his other force fields
Same
@@MurseSamsonLMAO
😂
I would like to hear more details about how it works, about strength comparisons, particle energies for certain scenarios and stuff. As far as I understand it now, it should rather be called "rare force" than "weak force".
I always asked myself "what the weak nuclear force actually do?" for years, never being curious enough to look it up. The popular books and shows always just mentioned the "it's responsible for nuclear decay etc.". And finally the answer came. Thanks!
Thanks Again for the Great Video Dr. Lincoln!!! I love getting to see the world the way you see it and hear all these parts of physics I may miss out on otherwise!
Have a wonderful week sir! ✨
THANK YOU...
PROF. DR. LINCOLN...!!!
Yes please on the deeper dives! The way you explain things is very intuitive (and comical at times) 😊
Always great to see another video by Dr Don!
Thank you. I needed this explanation.
I've been trying to fully understand the weak force for years! Thanks for the vid.
Great video! I have so many questions!!
1) If every fundamental particle has a range of possible masses, does each particle have a specific, definite mass prior to observation? Or is its mass fundamentally probabilistic like the position of an electron prior to observation? And what does this have to do with the Higgs field/boson? (This topic might merit a whole other video).
2) What causes quarks to decay by emitting W bosons? And what is the order of decay? You mentioned that a top quark becomes a bottom quark which in turn becomes a charm quark. Can a charm quark then emit a W+ boson to become a strange quark, which can emit a W- boson to become an up quark, and then a final W+ to become a down quark? Can lower-mass particles ever absorb W bosons to become more massive particles, or does it only go one way?
3) What about Z bosons!? You barely mentioned them!
Your videos are always amazing. Great content, thank you
Thanks for the vid, Don! The information density was very high on this one. I am pleased, and so is my cat. :)
Can't say enough good things about Don. Keep it up champ
You are extremely talented at explaining complex stuff . Thanks !
Please another video about weak force, very insteresting. Thank you Dr. Don!!!
Some laypersons contend that gratitude is also a force. If it succeeds in compelling, compelling content, all the more so. Thank you Fermilab (and all the other creators inspired by your contributions).
Exeedingly interesting, Dr Lincoln! Thank you!
Very nice explanation and Video. Thank you!
This answers a question that bugged me for a long time. Thanks, and please more deep dives.
Thank you! I've been wondering about this for years!
A great, short explanation about something that should had been learned when we learned about this force.
The hardest to understand of the forces, in an easy to understand video!
. Loved this deeper dive. Thank you.
I'd love to see more deep dives, Dr. Lincoln!
I'd definitely love a longer, more in-depth video about the Weak Force. I wish your videos were much longer in general!
I'd also love an explanation of the Pauli Exclusion Principle and how exactly it works, in terms of forces. I've heard so many conflicting explanations, each one stated with more gusto and certainty than the last, about something as simple as "why don't I fall through my chair?" and how that relates to "Why don't white dwarves collapse?"
Obviously the latter is from electron degeneracy pressure, which is related to the Pauli Exclusion Principle, yet nobody ever describes _how_ that happens. Sure, okay, no two fermions can occupy the exact same quantum state, but when they try, something _stops_ them. This is presumably a force of some kind, because F=ma. Without that force, the particles would continue to move closer to each other. The fact that they don't, means there's a force... right? But what force is it?
Similarly, I've heard descriptions of solid-solid object interactions as being governed by the electromagnetic force, but I've also seen very convincing claims, backed up by mathematical analysis, that says that would be far, far too weak, and that the real reason I don't fall through my chair is the Pauli Exclusion Principle, but... that seems very unlikely, and nobody has yet been able to explain to my satisfaction _how_ that happens.
So I'd love a video that can answer this question. When two particles get near each other, enough that their wave functions begin to overlap and they become at-risk of sharing the same quantum state, *something happens* to prevent that. What is that something? So far whenever I ask that question, all I get is "The Pauli exclusion principle prevents it." But that's just a name for some words describing a concept. Without more concept beneath that to be revealed, it can't prevent _anything,_ you know? There's nothing in there that feels satisfying in the same way that electromagnetism, gravity, or even the strong or weak forces does.
Excellent comment. I’ve wondered the same about white dwarves.
That is an excellent explanation under 10 minutes.
Love your episodes!
Excellent work an thanks, please do the "deep dive" into this topic
Finally and explanation that makes sense. Thanks.
I have watched this channel at 11 years old and this is amazing❤❤🎉
Man I love you videos. Thanks!
Thank you for this explanation, I learned something new today
Thank you. It might have been my question you were answering. I appreciate the Fuller deeper explanation. I see this RUclips channel as the place to go when I listen to other educational channels and I'm left with questions because of their abbreviated or over simplified explanations of physics. I first really noticed that when you addressed the twin paradox without having to arbitrarily invoke acceleration.
Would you consider doing a deep dive into the concepts are around Machs principle and the weird fact that acceleration is not relative? My guess is that it has something to do with the absolute geometry of space-time and the nature of causality, but I don't know.
Thanks! Very enlightening information about the Weak force!
I think a video would be helpful which would show simplified Standard Model's Lagrangian and explain how you can "read off", without any calculations, what its terms actually mean: how you can see which particles can interact, what determines the strength of interactions, what terms are not allowed by postulated symmetries of the theory, and what this means.
A LOT of people watching these videos never actually dab into math of the theory. Some seem to even coming to the conclusion that "science" is just some sciency-sounding words strung together and lots of handwaving (and they mimic this with hilarious results). They genuinely do not understand that there is actual rigorous mathematical "meat" beneath it, the handwaving is actually not allowed as a part of the theory. Everything has to logically come out of the math. IOW: they have rather erroneous understanding how science works. This is worth improving.
I enjoyed your explanation of a force with two boats and also between two particles. This is the case of a repulsion force. I would like to see a similar explanation for an atractive force. Thank you.
the ball has negative momentum
@@DrDeuteron That is a non-intuitive mathematical explanation, not very understandable.
one can imagine people on a big rug pulling the rug from each other. These are no more than vague illustrations/metaphors, don't expect them to correspond precisely to quantum processes.
@@jaimeduran9423 well virtual particles have the energy and momentum required to conserve energy and momentum between the two real particles, after the fact. So in a bound circular orbit, that would be energy = 0, momentum < 0, mass--> imaginary.
plus: the exchange is not time ordered...it's not like one emits and the other absorbs. There is no intuitive value to the analogy.
Dr. Don is a force, too. THE force. May he be with us!
Cool topic Don, thanks.
Best explanation of this ever
Definitely need a deeper dive with explanations of how neutrinos interact using the weak force.
So you know how quarks interact with it?
Think of that, but keep in mind that a neutrino is a "down lepton" while an electron is an "up lepton".
@@orbismworldbuilding8428 > a neutrino is a "down lepton" while an electron is an "up lepton".
The opposite. e- needs to emit W- to become a neutrino. d needs to emit W- to become an u. Thus, electron is a "down"-type particle, and neutrino is "up"
@@denysvlasenko1865 oh cool! I didn't know that
Very good to know
@@denysvlasenko1865 thank you!
I would love a deeper dive series!
Nicely done.
Toujours aussi intéressant MERCI
Very interesting, thank you!
Thank you, this helped a lot!
I agree with many that the deeper dives are very interesting and I personally would like to see more of them.
Awe at those opening and closing cards!!
Dear Don,
I'm an avid fan of the videos you release on a regular basis and grateful for the hard work you put into making particle physics more accesible to the audience. I was wondering if there would be on option of making a video regarding weak hypercharge and weak isospin with the perspective of how and why (to our best understanding) matter gains charge as this has been buggin me for a while now.
I understand that currently our understanding and explanation is that there needs to be a conserved quantity for every symmetry (thank you Emmy) however you of all people should be aware how new perspective of various attempts of explaining the same phenomenon could lead to new insights for some people
Is degeneracy pressure a force? It's the most common "force" we feel in everyday life - the "force" that pushes back on us when we push something and the "force" that keeps us from sinking into the floor.
Great video.
Thank you for the excellent video. Actually, you have defined the general concept of a force, which means to change a state of an object - a particle's position, its identity, its quantum state, etc. A physicist comes to this general concept of a force when he or she steps into the philosophy of physics.
I'm interested in quantum- and astrophysics since I was a child, but I never heared of the mass-distribution until now. You, Sir, blew my mind today.
Absolutely I want to hear more. 🤩
Another channel in Germany calls it always: 'Eine Tiefbohrung setzen' and I love it. 😊
Best channel ever!
Wow! I had no idea. After all the physics I've learned and explanations I've heard, this was new to me.
Great video
Nice one !
I need an even deeper dive! I've never heard any of this before, and hearing it now tells me there must be more! I want the titanic of deep dives
Dr lincoln back at it again 🔥🔥
Thank you very much. It is definitely the best (which means the most concise yet not oversimplified) physics RUclips channel. Fermilab did the God's work when decided to launch it and promote real scientific knowledge on every platform possible.
What a week ! JWST detecting CH3+, IceCube results for high-energy neutrinos and NANOGrav's evidence for the gravitational wave background. I'm looking forward to learning more details about all those great news (or at least some of them) !
Excellent deeper dive
Excellent t-shirt 😎
Fascinating.
I think it is interesting that you talk about the weak force and mention quarks and Zs and Ws, but not a mention about the beta particle (electron) or the neutrino (and their anti parts) which are actually produced in the decay.