The Weak Nuclear Force: Through the looking glass

Of all of the known subatomic forces, the weak force is in many ways unique. One particularly interesting facet is that the force differentiates between a particle that is rotating clockwise and counterclockwise. In this video, Fermilab’s Dr. Don Lincoln describes this unusual property and introduces some of the historical figures who played a role in working it all out.

[@juliafreitas2905]

Thank you so much for recognizing Wu Chien Shiung's relevance... as a young grad student I constantly feel insecure and afraid if someday I'll be overlook in science just for being a girl... what you said made me feel so happy and proud and also recharged me to continue on studying hard so that one day it can be me making a huge breakthrough in the STEM field! I really look up to you, Dr Don... Thank you for all the things you've taught me and for being an amazing person.

[@derblaue]

I didn't even know those 2 guys but only Wu. I guess my prof did at least one thing right by explicitly teaching us the Wu experiment,

[@guff9567]

@@derblaue Don CLEARLY hates Chinese men. You can best this is because he once offered his tender heart to a woman and she rejected him for a superior Chinese male.

[@zack_120]

Dr. Lincoln.

[@user-fw1bu6fd2i]

​@@zack_120💀, right😂

[@abebuckingham8198]

Ever since we've allowed women to go to school they have outperformed men academically. I looked for many possible reasons this could occur and the best explanation I can find is that women are simply smarter than men. In another hundred years this will be obvious to everyone and you and other women will be the reason. Keep it up.

[@donwald3436]

She also skipped a long-planned vacation to run the experiment herself. My hero!

[@MottyGlix]

Does anyone still use the word "heroine" for the female version of "hero"?

[@StanleyKowalski.]

@@MottyGlix it is still used

[@NoNameAtAll2]

@@MottyGlix noone likes heroin

[@johnny14980]

@@MottyGlix yeah nobody cares

[@rakeshsangwan6846]

Mrs Wu definitely deserve a Nobel Prize. We should keep raising our voices for this issue so much that a separate award is created to honour all those who deserved but were left by humanity in the past 😋

[@LunizIsGlacey]

That's a neat idea!

[@zack_120]

Excellent idea! This would give the Nobel cmt. a chance to correct itself, Unless it refuses to improve.

[@ghanshyam1990]

Really sad to learn that she was overlooked, her experimental design is brilliant!

[@mukeshsharma-iq8dp]

It happened also the discovery of the DNA., in Nuclear Physics- there is a long list of injustice that half of humanity suffered because of their gender......MCP was big and many women in Science got the short-end of the stick. I think its high time now to redress these mistakes and give them their due recognition,

[@guff9567]

Pointless

[@zack_120]

And her unmatched experimental skills. Read somewhere that many experimental scientists failed in carrying out the experiments until Professor Wu walked in.

[@dlbattle100]

To be clear, he also isn't on the Nobel prize committee now either. Had me going for a minute there.

[@pavel9652]

Exactly, I wasn't sure what it was supposed to mean, the joke was too hermetic ;)

[@kostantinos2297]

"Now, neither of these guys knew how to test this because they were *_cough_* theoretical physicists"

[@govamurali2309]

Angry Sheldon noises

[@curlykiddell368]

The shade 😂

[@naveedsegments]

Small dog barking

[@zack_120]

It's not hard to imagine how the Nobel cmt is blind and corrupted by ignoring such a landmark contribution of Mr. Wu. The discovery is historical also beautiful by iteself: the weak force only likes left handed particles, which may imply huge potential for future discoveries.

[@EugeneKhutoryansky]

At 2:35, what I think what you really meant to say was that if we measure the spin in the direction of motion, then it will be parallel or anti-parallel. It will be another matter if we, for example, instead measure the spin in a direction perpendicular to the direction of motion.

[@harsimratdhaliwal2806]

aye your videos go hard

[@MrVankog]

I've been wondering about the nature of the weak force for years, because it seems noone is covering this topic in depth. Finally a first step! *However, the video still hasn't taught me much about the weak force yet. Only about its preference for a certain spin.* I hope more is coming :-)

[@MrVankog]

Yeah, it sounds like it.

[@malcolmabram2957]

The weak force simplistically is concerned with nuclear decay, but it governs the structure of atomic nuclei. In some ways it is the most important of the forces. Without it atoms would become a chaotic mess of anything goes.

[@pureenergy5051]

@@malcolmabram2957 The word "decay" means transform. You don't know why forces exist so you don't know that there would be a chaotic mess

[@malcolmabram2957]

@@pureenergy5051 Thanks for your reply. The weak forces is why there is a periodic table of elements, without which matter would become chaotic. Nuclei cannot get too big, and there must be a balance between neutrons and protons. The question is identifying the rules that govern the way the weak force behaves. Why is C13 stable, but C14 is not etc, etc, etc?

[@pureenergy5051]

@@malcolmabram2957 For 35 years I have been reading that all subatomic particles are governed by consciousness. There is major reason why there are forces, otherwise why use the word "behaves"? The rules are the purpose of why we are being created in the first place.

[@adamarchy]

I am so glad I follow this channel. Thank you, Dr. Lincoln!

[@williamfrederick9670]

You explain everything perfectly I'm beyond awe-inspired by the content of this channel

[@agarwalamit081]

I finally subscribed to your videos. It really brought back the motivation to learn more of Physics and revise my maths. You have kept the videos simple (not necessarily easy to grasp everything though) but included bare minimum information to get an insight into the topic.

[@anthonywilbanks8189]

I really enjoy all of these Don Lincoln videos. thanks for making them

[@pronounjow]

After watching this video (a couple of times so far), this is the first time I have any understanding of the weak force at all. I'm looking forward to more videos on this and related topics!

[@pronounjow]

***** Please!

[@wexer82]

I'm so glad I came upon this channel.

[@richthenative]

Did not now of these three physicists, thanks for the annotation pertaining to spin. Special thanks for the important history lesson. Reminds me of Watson-Crick and Franklin, whom was essentially passed by. Good to make things right to help keep us on track to do the correct thing...always. Great series of educational pieces from Fermi.

[@alexjaybrady]

Her experiment showed something stranger than pretty much anything else ive heard in any of these great videos, and theyre all often mindblowing.

[@slalibert]

Great video on a mysterious and fascinating subject. More please!

[@stephenlee685]

Thank you for this video. My father very much wanted Dr. Wu to join in the prize. It's interesting that this video comes from Fermi Lab, The Fermi Lab's first director, Robert Wilson and Dr. Wu both worked at Berkeley at the same time.

[@bcddd214]

Loved the ending! I adore this series!

[@bruinflight1]

Every time I see a new upload on this channel it's like a stadium of avid football fans cheering a touchdown in my mind :-) Thanks Dr. D!!! Keep 'em coming!

[@ednwab]

Well done for showing how important she was, a similar issue relates to Watson and Crick, Rosalind Franklin is hardly ever mentioned but it was her fabulous X-ray work that was critical in the discovery of how DNA fits together and works.

[@alexandrugheorghe5610]

Thanks for this great video Don.

[@federicopasqua3916]

"Theoretical Physicist" -cit. I laughed. I laughed a lot

[@alibinkhalid9289]

another great video as always. thank you man

[@jaykariansaul4911]

Awesome vid! i love the fact that what ever this science is it keeps evolving and we keep learning new things!

[@maurod6180]

THANKS FOR SHARING THIS CONTENT!! one of the best videos of youtube...

[@opioid01]

A woman studying a discriminating force..got discriminated on. The irony😅

[@tokamak4219]

I love your vids! This one should be a blast

[@dAvrilthebear]

Subscribed! You are probably the first channel on youtube to touch the spin the weak force. However, as some commentors below/above, I hope for more videos on these topics. What does the weak force actually do? How does it do it?

[@markandrews1219]

Thank you for another informative video. I am even daring enough to take credit for motivating this video being made since I requested a video on the Weak Force several months ago. Hopefully the next amazing video topic will cover why the electron does not crash into the nucleus and if it is a standing wave or point like object held in an orbital. A more serious question....if the other forces do not care about spin...how do we explain the alignment of electron spin with magnetism?

[@weixiong1.0]

She is the best and the most influential scientist unknown to the general public, an Unsung hero of humanity.

[@davidroux7987]

Sir Your explanations are a treasure. So clear. A good account of the Wu experiment is given in Krane's Introduction to Nuclear Physics.

[@UshiromiyaXyrius]

Amazing explanation!

[@markholm7050]

Why is there not a playlist for Dr Lincoln's videos on the Fermilab KZbin channel?

[@pabloagsutinnavavieyra2308]

I'm very intrigued with the begginig of the video. Those other fuzzier forces where do they appear? Is it related to technicolor? I want to know please!

[@tresajessygeorge210]

THANK YOU PROFESSOR LINCOLN...!!!

[@mrgd7813]

U r awesome, doctor. Thank u..

[@horacioperezvonrossum5597]

Where can l see video # 2 from serial You start yesterday, can't find it. Thanks Dr. Lincoln.

[@vincentrusso4332]

Never to late to award a noble prize in her name or honor, and the next video I would like in GED format.

[@UrgeidoitNet]

love this !

[@agmessier]

I've never hear that before about the spin of a particle being aligned with the direction of travel. But doesn't the direction of travel depend on your frame of reference? How can spin be an attribute of the particle itself if it depends on who's observing it?

[@orjanlindunger2731]

I have watched this video a couple of times but now (on a bigger monitor) I discovered the neutrino oscillations taking place on Don's shirt. 😂 Thanks for a great video!

[@Gary_Allan111]

great video

[@josemariodelapiedra611]

I had the honor of meet her at CERN I’m 2018 . I do admire her to

[@carrellwashington4007]

Hey! Does anyone know where to find the video playing in the background at around 3:10?

[@simonmcgrath4112]

Dr. D u r the man!!

[@ravenous9577]

Thanks this is really awesome! Ive wondered about these things for ages, but I have one more question that keeps bothering me... why is using the weak force to transmute atoms so inefficient? I cant remember perfectly, but i heard a story about a man who held an experiment with tons of gallons of chlorine, but when using the weak force he only got 3 boron (i think it was boron) atoms out of it. I understand that you need the electrons to get super close to the atom in order for the neutrinos to hit the quarks, but i still dont know why the weak force can be so inefficient.

[@pulley1fan]

I know its difficult, but have the neutrinos from these interactions been confirmed as left-handed? With all the news about symmetry breaking, is it possible there's another one here?

[@gutterball10]

how do they account for the interaction of the electron with the magnetic field being subjected against the Cobalt? or the magnetic field being created by the alignment of all the electron spins in the material?

[@KetoCrush]

I love your channel...truly...but what does this mean? You explained the nuts and bolts, but not the implications, unless of course that went entirely over my head.

[@roneyandrade6287]

I'll one day be a particle physicist

[@IronMan-qi3yg]

Sash or chicane?

[@dirtperson5234]

Crack or meth?

[@JC-je3jc]

Did you just assume my collapsed wave function?

[@SaadMohammedGhori]

Go for it bro!

[@yuutaakagami2406]

amen

[@veganevolution]

So does this suggest that the weak force is an efficient way for increasing order since it will turn random direction into a certain direction, with no extra energy input to the system?

[@mathmachine4266]

So...the spin is different depending on the chosen reference frame?

[@ranjanarch4890]

Can you describe(graphically) what actually spin is in quantum work? If you are saying the sub atomic particle is not classically spinning then how is it moving? I am not interested in the number given to spin but its actual physical movement.

[@orconvacation]

Can you please do a video about the upper limits of temperature (if there are any), and about the recent discovery that the weak nuclear force and electromagnetism, in high temperatures become one and the same?

[@anteconfig5391]

I'm wondering about the weak force. We can perturb the electromagnetic field by actively spinning magnets around and controlling the flow of electrons in a conductor, but are we any close to being able to harnessing the power of the weak force.

[@Darkanight]

I love Dr. Lincoln

[@duncancampbellauthor]

I have 3 daughters. This story pisses me off ... and makes me very happy. Wrongs can be righted! Wu never got the Nobel prize, but she got recognition on the Internet! Guess which one has more fans?!?! Thank you, Don!

[@Super_Beast124]

Well said sir, we agree completely

[@anttumurikka8728]

can spin run anything else than left or right like both way same time or both ways randomly

[@01rai01]

Never been so outraged by the end of a Fermilab video

[@cgaccount3669]

But madam Currie won 2 Nobel prizes at a time when it was even harder for women in science. And we also have to remember the Nobel prize is like the Oscars. Only an elite few get a say

[@VanDzungNguyen]

Why at 4:49 electron has spin +1/2? Did I misunderstand something?

[@matthewclark1006]

Don is freaking amazing

[@lartinmindahl]

Pls tell me where you find all your cool t-shirts.

[@PakornThaipituk]

With all respect, I am curious your explanation spin directions (are they called chirality?) at 2.36. Is this only true at ultra-relativistic limit? Or if the explanation is always true, how can I think about spin of an electron at rest? My understand is, for example, an electron (at rest or slowly moving) can have spin in arbitrary directions. Once an external magnetic field is applied, the spin's directions are said with respect to direction of the magnetic field.

[@ffggddss]

Gee, I was sorta expecting at least a mention of electroweak unification. In particular, how did Glashow, Weinberg, and Salam manage to do that when EM doesn't care about chirality, while the weak force does? Or was that, 'beyond the scope of this text?'

[@Gitohandro]

ffggddss Go look up his video "why is the weak force weak"

[@user-ib4pe7si5b]

Can someone help me out with 4:50... i.e. why the decay of electon or anti- neutrino would be in/opposte the direction of the spin of cobalt nucleus spin?

[@richardbraakman7469]

How was quantum spin even discovered / measured before the discovery that the weak force responds to it?

[@SIUL1970ABC]

I cant find the electromagnetism force video. Any hint? Thanks.

[@japiereinders626]

I try to understand...... Thanks! It helps....

[@42ckev]

Can you explain W & Z bosons please?

[@hoggif]

That was a very good video! You could perhaps explain more about spin and what it really is? As far as I know it is not real rotation like in the macro word but I've yet to see an explanation what it really is. (It is often described as "like spinning macro object but not really spinning" which leaves out what it *really* is!)

[@maxrothman7368]

hoggif I believe that the spin corresponds more to the symmetry of the particle, as in how many times you see the sameface during its rotation. I hope this clarifies it.

[@richardpaulphilips9561]

Max Rothman But the particles isn't rotating at all! In fact, elementary particles doesn't have spacial dimensions. Think of spin like you think of electric charge: We know what it does but we don't know what it is. Spin is just like that: something we can measure, like charge, but depends on how we "look" at it. Let's be honest: Nobody knows what spin is, neither what charge is. This lack of knowledge is what pushes science forward!

[@nmarbletoe8210]

Try this: spin is the second result of Noether's theorem for rotational symmetry. The first result is conservation of angular momentum, the second is quantum spin.

[@otballard]

I love Don.

[@tims.440]

Could someone please point me towards his video on electromagnetism? Thanks.

[@MakeMeScientific]

good one sir. #makemescientific

[@user-xx1ib8mx8j]

The same happened with Franklin on DNA structure with Watson and Crick in the biology world.

[@jballenger9240]

Your a magnificent scientist for letting us know about the the extraordinary female scientist, Dr. Wu. Sadly it seems not giving credit where credit is due, continues. Thank you for keeping her name alive.

[@koenth2359]

Throughout the video there is an interesting particle formation on on you shirt... where the leptons and their neutrinos interact! First direct observation of the W boson!?

[@dp0813]

Great video! The pace is perfect and extra points for pointing out Wu's accomplishments & contributions. I'm no social justice warrior but credit should be given where it's due! 👍

[@dellaroccia]

the spin is something I never really understood. you say the spin is aligned to the direction of motion. but motion is something relativ to a point of reference. what is the spin of a particle when watched from different inertial systems that are in movement relative to each other or whats the direction of the spin when the particle doesn't move at all?

[@nmarbletoe8210]

True. What happens is that when the spin is measured, it always points aligned or counteraligned to the magnetic field that is used to measure it. If the spin was in-between before measurement, this skews the probability of the two results. But the results always are either "up or down"

[@lastblow4563]

The 2 guys will live in infamy for taking credit for Wu Chien Shiung's work and keeping the Nobel Price for themselves! Thanks, Don, for doing her justice.

[@pavel9652]

Not necessarily. I don't know the full story, but it depends on the details. Did they provide the full documentation or did they hide her contribution? If it was an external decision from the committee it is not their fault. It would ruin the prize for me myself, especially if she was my colleague.

[@nmarbletoe8210]

NO it's not their fault

[@michal.gawron]

2:45 The direction of motion is relative to the observer. This means that spin will be relative to the observer doesn't it? Which means if there are interactions involving spin direction, then they will look different for differently moving observers, right?

[@alienrenders]

You'd have to travel faster than the particle to change the relative direction. I'm not even going to think about what happens to different frames of references interacting at the quantum level.

[@WedersonWinchester]

This thing is absurdly interesting.

[@ModestConfidence]

ty all gems

[@yzyz7779]

Tq info professor 👍👍👍that means weak nuklear force got his positions on powerful strong nuklear force because trigger by electromagnetic?so weak nuklear force is actually Electromagnetic on evolution 2 perhaps?

[@fuseteam]

Start by making a playlist of all you particle physics videoxD

[@EyeOfAllah]

Weak Force should be called Change Force and Strong Force should be Binding Force

[@juvnchy]

ok Marie

[@sqwirl05]

Except that the strong force becomes repulsive at extremely tiny, near-Planck scale distances. That's what causes degenerate neutron matter, like in neutron stars, to resist gravity's attempt to pull the matter (or crush it, if that makes more sense in a mental picture) into the infinite density state of a singularity. Without this aspect of the force, there would only be black holes, no neutron stars. So in this case, it's more of an unbinding force since it resists gravity's push to . That's quantum physics, just when you think you get a handle on it, here come the notable exceptions!

[@noahzaeshorts1402]

@@sqwirl05 As far as I know, the repulsive pressure in degenerate matter is caused by the Pauli exclusion principle, not by the strong force.

[@sqwirl05]

@@noahzaeshorts1402 My mistake, you're right. I was thinking of nucleons in general, but if the particles are the same, then, yes, the Pauli force is far stronger than the short-range strong force repulsion effect. So, the strong force repulsion keeps a proton and neutron separate by > 0.7 fm, but the Pauli force keeps two neutrons or protons apart.

[@Feyser1970]

@@sqwirl05 stop inventing things

[@dans4323]

Love your videos! But this one, instead of answering questions it just created more questions. Especially, when you jumped to the conclusion that this means the weak force cares about spin you should have explained why it would mean that.

[@harthur2010]

Oh, nice dig on "Theoretical Physicists" :)

[@wesamhashish9]

You talking to me :)

[@loge10]

Not being a scientist, I thought he was going to say it was because they were Chinese... It was the 50's after all...

[@ulriklm1]

He didn’t explain the weak force, just talked about spin and that experiment

[@guff9567]

... and then shat all over it with gender politics

[@MC-hm5pc]

I ended up here through the KZbin rabbit hole, guess I have a new interest now.

[@jamesruscheinski8602]

Could have a Nobel prize for experimental as well as theoretical science

[@GuerrasLaws]

Force (physics) does not exist physically in the same way that an object with mass, thus making it “not” the initial cause of pushing, pulling, shaping objects, motion, work or being a Vector Quantity (Magnitude + Direction). In physics, the word, “Force” as we know it, turns out to be nothing more than an expression to express an idea, like one would use the word “Love” to express one's feelings. But, physics and in mathematics, still use “Force” as thou it were something physical that could enable the initial cause of motion making it counterintuitive. Example: Without applying the Energy from within you, choose an object of your choices to push and pull by simply applying “only” the Force or Net Force. Meaning that Energy (applied energy) is the origin of motion and not “Force”. Once Energy (E) is applied, it creates what is known as Momentum (p). When this Momentum (object in motion) comes in contact with another object(s), it makes a surface contact that will enable you to push and pull. Example: Ep=ma, Ep=mv and so on. Note: Ep is not to be confused as Kinetic Energy in any way. Momentum represents things like work, wave, gravity, light, lightning, tsunami, earthquake, current, electricity, motion, magnetism, hurricane, etc. Without Energy, there is no Momentum. Without Momentum, there is no surface contact on an object(s) to push, pull, work, shaping objects, motion, etc. Momentum does not and cannot exist without the applied Energy that creates it. Energy and Momentum or “Ep” is the one and only common denominator that links all fundamental forces of nature. Without Ep, all fundamental forces of nature would be inert and non-existence. Energy is energy, but it’s when Energy (E) is being applied that creates the Momentum (p) making it the initial cause of motion. Example: Ep. By applying the right amount of Energy, nothing is immovable or unstoppable. ~ Guadalupe Guerra

[@VladVladislav790]

I am hearing phase issues in the sound of this video, maybe you should try treating walls and/or floor and/or ceiling of a room, you are recording in, so mic would pick up only one source of sound, instead of all the reflections

[@jamesruscheinski8602]

Beta decay of neutron through weak nuclear force leads to electron as well as proton? Electron has to do with difference between neutron and proton? Since difference between neutron and proton is up and down quark, does beta decay have to do with change from down quark in neutron to up quark in proton (if have description of quarks in neutrons and protons correct)? Beta decay (electron) through weak force from down quark in neutron change to up quark in proton from strong nuclear force demonstrates relationship between weak nuclear force and strong nuclear force?

[@Markoul11]

Actually, spin quantum number ms of fermion particles at rest (no linear motion) is graphically symbolized with the rotation arrows shown here in this link, drive.google.com/file/d/1N73sd_6tVAlzHHvxSa2beXNl2KZTZh-t/view?usp=sharing but because the "spin up" +1/2 and "spin down" -1/2 added text characterization to these quantum numbers, there is a great confusion and mix up also among physicists with the magnetic moment vectors convention symbol which are opposite direction to the spin up and down characterizations for left chirality fermion particles, if you get them literally as up and down directions (which is wrong practice in my opinion and confusion created due the right hand rule applied to visualize spin). As you can see in the linked image, spin down ms=-1/2 is actually opposite to the magnetic moment vector which is clearly is pointing up S to N which is counter intuitive. In the case of Right handed chirality fermion particles like the positron, the magnetic moment vector agrees with the spin up or down direction text characterization. Again, quantum spin of particles should not be confused with linear vectors like the magnetic moments. update: What the denotations "spin up" and "spin down" as shown by the direction of the thumb is pointing when applying the right hand rule for visualizing the spin of the particle at rest (no linear motion) and wrongly assumed by many as the spin vector (which is not), is a actually the mechanical angular momentum vector. Imagine it as the direction a screw is going, thus up or down when screwed in or unscrewed.

[@ciudadanubis]

Don. Is this an explanation why there are no antimater in the universe?, I mean, because I'm engineer, not physicist, I'm wondering if this interaction of the weak force may explain why the universe is full of matter and without antimatter. If the experiment shows that Co60 decayment always is with certain spins of the electron and neutrino... ¿Is this relevant?

[@frankschneider6156]

+ciudadanubis Yes, that's actually the current best guess. The weak force has also more similar asymmetric properties and there are a ton of other similar experiments (this was just the first one). It's thus reasonable to assume, that the perceived asymmetry between matter and anti-matter of the universes resulted somehow from this.

[@frankschneider6156]

+ScienceNinjaDude True and it's imho primarily a gut feeling, just making a connection between two anomalies. But understanding that would imho be Nobel prize wothy. If we would be able to somehow really understand what was going on, that would massively deepen our understanding of the early universe and the forces that govern it. It's especially interesting as the strong and the electromagnetic force who are thought to be incarnations of the same general force do not exhibit such a behavior.

[@naiteakhiangte1773]

ciudadanubis The anti-matter you called is prevalently known as Dark Matter (of Dark Energy). This is not a new issue of the scientist and is also portraited in TV series like The Flash (althought it was just written to best suit for the series and is not meant to argue with physics).

[@joebender3662]

An excellent conjecture I don't know if it is true or not but it is suggestive and maybe there are other asymmetries which also favour matter.. bravo to that connection!

[@DFPercush]

This may shed a small light on your question, although he goes on to say that this does not explain everything. But, there is a difference in the time it takes certain particles to decay based on whether they are matter or antimatter. kzbin.info/www/bejne/Y4mvf2hrgdtmibMm15s ... the preceding video is kzbin.info/www/bejne/ZnKnnoaJmrWoo80 if you're interested.

[@pifdemestre7066]

How are we able to measure the spin of a particle ? I can see two scenarios: 1) with the interaction through the other forces, hence spin matters for this interaction. 2) with the interaction through the weak force, hence we already knew that spin matter.

[@ikarienator]

Spin matters but the direction of spin does not matter for the other forces. Just like the electric charge matters but whether defining the charge of an electron to be positive or negative doesn't matter. By changing the spin, other forces simply act as if the particle is mirrored. After all, mirroring a spinning object changes its direction of spin. Not for the weak nuclear force, a mirrored particle behaves differently in such interactions.

[@pifdemestre7066]

ok, it seems to be a matter of symmetry. If I properly understood it mean that if you show a record and its mirror image of an experiment with the three other forces you cannot say which one is the true one (but people will assign opposite spin to particles). However with the weak forces, scientific could tell this one it the real one, and this one is the mirror.

[@ikarienator]

Pif de Mestre in fact it is proposed that we can use this test to communicate with extraterrestrial civilization to establish scientific conventions, that is, those signs that we defined arbitrarily.

[@azarashichen]

Side note: any Chinese-speaking person would presume Wu was a male if they only knew her by name. Wu had a given name typically given to a male.