Can you tell us initial assumptions (contrary of what you explain in the video) are coming from, i.e. why are neutrinos supposed to be massless and NEVER interacting? I'm over 30yo and I always heard that they probably have a very tiny mass and they barely interact with the matter, but hearing that the mass is supposed to be ZERO and they NEVER interact is a fresh concept to me! Where exactly does it come from? What's the reason behind expecting them to NOT have a mass, nor interaction?
Neutrino physics is the final frontier (for now) in particle physics. It is bound to result in brand new physics sooner or later. Hats off to all you brilliant scientists working on the mysteries of the universe!
For those who don't understand why oscillation necessarily implies mass, it's because they experience time, and massless particles do not experience time.
'massless particles do not experience time' - I've heard this aplenty for photons, yet it still makes my head spin. Like what does that even MEAN?! How do they travel if they don't experience time? Would a photon emitted at the beginning of the universe that didn't get absorbed by anything just 'see' the universe's end as soon as it was created? But in that case why wouldn't every other photon 'see' the end as soon as it's created? What's it like to 'not experience time', yet still be doing stuff that takes time?
@@ArawnOfAnnwn It's important to keep in mind what is meant by time. In physics, it refers to what a clock is showing. So what is a clock then? It's essentially any well-defined, measurable, periodic change. A second is defined as being a specific number of energy level transition changes of electrons in a Cesium 133 atom, for example (it's approximately 9.1 billion). So then if you have the right equipment to detect those changes, when you see that the 9.1 billion changes have happened, you know that 1 second has passed. However, if that Cesium atom begins to move relative to you, Special Relativity says that the amount of time it appears to you to take for those 9.1 billion changes in that moving Cesium atom to happen begins to grow. The closer it gets to light speed, the slower they appear to happen. If it was possible to accelerate that atom all the way to light speed then the changes would appear to you to stop happening entirely. If a measurement device was moving along with the Cesium atom, it would record the changes as happening at the same pace they appeared to be happening to you before the atom started moving. But that's because that Cesium atom is not moving relative to that measurement device. However, because the measurement device is moving relative to you, you wouldn't see it changing for the same reason you didn't see the Cesium atom changing (time dilation). In reality, nothing with mass can reach light speed so it wouldn't be possible for the Cesium atom to seem to completely stop those changes. But they will appear to slow way down as it gets closer and closer and experiments have measured and confirmed that this phenomenon does happen. Indeed, GPS satellites have to take gravitational time dilation into account because time also appears to pass more slowly the closer something is to a gravity source and so clocks on Earth tick slower from the perspective of the satellites orbiting up above Earth than the clocks on the satellites themselves do.
@@ArawnOfAnnwn Actually, massless particles also don't experience any distance either. So from their point of view they travel 0 distance in 0 time, which works out just fine.
@@Boopers So everything just comes at them? No, cos that would imply both distance and time still. So everything that they're ever going to interact with has already hit them as soon as they were created? Said interaction absorbs them, so did they ever exist to begin with? Do they even experience their own existence, when they don't experience any time of said existence? Just what is their existence like?!
@@ArawnOfAnnwn You can interpret it this way: Due to length contraption, which compresses length towards zero for an observer as they approach the speed of light, the perception of any finite distance in the direction of motion for a light speed observer (which massless things like photoons will be) is zero. From the perspective of a photon the universe is compressed into a perfectly flat sheet they are imbeded in, so they are literally always in all the places their trajectory will move through.
Also since right handed neutrinos would be very heavy and would'nt interact in any way but gravitationally, that makes them theoretical candidates for dark matter too
Hold the phone! The Higgs mechanism comes from breaking chiral symmetry? Is there a way to grasp this as a lay person without formal instruction in QFT?
kind of? It definitely makes more sense to me than it used to, but imo there's an upper limit on how "familiar" some topics within particle/astro physics can be. Like yeah, you can see dozens of models and come up with hundreds of metaphors and crunch mountains of numbers, but at the end of the day it's still always going to _kinnddaaa_ seem like black magic 🤷♂ (and I think that's neat; so much of theoretical physics deals with topics that are inherently unfathomable for humans... yet we dare to fathom anyway!)
I'd never heard of Ettore Majorana before today, interested to learn more about him esp. considering the praise he received and who said it. Another great video. :)
Are neutrinos “important” in everyday particle interactions? I.e. is their miniscule mass and difficulty in detection indicative of a very miniscule but important effect, or important for our understanding but largely irrelevant effect? (Example might help: detecting proton decay might be very interesting and helpful for our understanding, but the difficulty in detection is because it’s so rare as to be irrelevant for any experiment that isn’t itself trying to detect proton decay)
They are important in supernova explosions. Without the interaction of the neutrinos (i like to call it neutrino wind) the outer shells would just fall back on the core and the higher chemical elements generated in the fusion in the stars and in the supernova explosion could not leave the star remnants. Without them life as we know it would not be possible. Not to forget that without neutrinos a lot of the nuclear decays would not work.
If we are speaking about Majorana fermions, are we saying that these right handed heavier siblings may be Neutralinos? (which is one the coolest "and coldest" dark matter candidate by the way). Description actually fits Neutralinos but I happen to remember Majorana fermions instead of Dirac fermions to have mixed chiralities as they are their also own anti-particle.
Hey hey hey! Have anyone noticed the Fermilab bulding in the Netflix "Three Body Problem" new series? It's in the third episode, at 41:00 when the game AI does an exposition to Jin and Rooney and the Follower advances time. Or is it?
What if neutrinos are rotating not just in the 3 position dimensions but also in the 4th time dimension? If that were the case, would we observe as a small mass change would actually be the speed of time oscillating.
I keep wondering if there is some property or field they interact with such that they don't actually experience time and really are massless, but because of how we measure, (or similar) they only appear to oscillate.
What do you mean by “speed of time”? This doesn’t seem to immediately offer a meaning, other than “1” (1 second per second). I guess if you fixed a coordinate system you could talk about time per proper time, or proper time per time? What do you mean by “speed of time”?
Would right-hand (heavy) neutrinos somehow interact with left-hand neutrinos? And by having mass, would they also undergo some change in time, an oscillation or such? Oh, and should neutrino (the ones we know, left-handed) oscillation actually include some particle interaction, some exchange of hypothetic other particles between neutrinos of different flavors, which is not detected or detectable right now?
I find it rather amazing that during the collision of neutron stars, the hypernova releases much of its energy in the neutrinoes that drives the Rapid process synthesis of heavy elements, IIRC.
Is the diagram at 2:45 wrong? On the bottom right it looks like the symbol for a Muon Anti-Neutrino, but Beta Decay emits an Electron (Anti)Neutrino, not a Muon Neutrino. Anyone want to chime in, let me know
They would have to have longer wavelengths (-14 range) to be massless, like a 100MeV+ gamma ray. Too much energy in a neutrino. The permeability of the Higgs Field is what, 127-ish?
with disturbances between energies (which spread in forward spirals), vortices arise, which make these energies appear as matter, and in energy fields such as the Higgs, a torque is exerted on these vortices, this torque creates an apparent mass, a quantitative gravity,
It's weird that it would be surprising that neutrinos interact, since how could they be created if they don't interact at some level? Just reverse that reaction, and it's an interaction.
@@while_coyoteYes, I also thought that comment was odd! (I think the “if the interaction producing them is possible, then the interaction absorbing them should also be possible” thing should follow from the Lagrangian density being self-adjoint. Like, if there’s a term that has a creation operator for the neutrino, the Hermitian conjugate, which should include the annihilation operator, should also be included)
My understanding of electron mass is that it's caused by the Higgs Mechanism, which causes electrons to rapidly oscillate between left and right handedness. My question is, could neutrino mass come from the mechanism that causes them to rapidly oscillate flavor?
F=ma and E=mc. If it exists, it has mass. The question is, what kind of mass? Atomic mass or Radiant Energy mass as in an electrical charge. A photon has mass in that it has an electrical charge. It has mass in that it has a wavelength. Mass is Space and Space is 3 dimensions. Or in the case of photons, one dimension which is its wavelength. E=mc. If it has an electrical charge, it has mass. Atomic mass if the acceleration value is < c. Otherwise Radiant energy if = c. First you need to understand what mass is which is just energy. What you should be asking is; what is mass at absolute zero aka. Zero Acceleration/No energy.
You have hit on a very important "domain lexicon" confusion in the modern world. Somebody in the hard sciences will have a very different definition of what "theory" means compared to the general public. To the general public, the word "theory" mostly means an unproven verbal explanation for why something has happened. As you point out, in the hard sciences this is considered merely a hypothesis. Then the math fun starts. The next step is usually to try to find mathematical relationships that predictively describe this hypothesis. You are now at the "model" stage. If your model survives comparing outputs with other well tested models, theories, and observations, only then does it get to the status of "theory" in the hard sciences. Unfortunately, this distinction is incredibly difficult to explain to most people.
A hypothesis is a guess that can be tested with an experiment. A theory is a model for a phenomenon. They're completely different categorically. A theory that doesn't predict anything can still be a theory, just a bad one.
I understand why Dirac spinors have a left- and right-chiral Weyl spinor because of non-equivalent SL(2, C) representations, but I still don't understand why the weak force only binds to left-handed fermions. Maybe one day.
Neutrinos have mass. Or the theories from which we deduced that are wrong. It wouldn't be the first time it turned out the latter was the explanation of an anomaly in physics. We make experiments to try and assess the mass of neutrinos. And keep on reducing the upper bound to the neutrino mass. But upper bounds for the mass aren't as helpful as lower bounds. What if the neutrino weighs 0.00000000000000000000000000001eV or something, can we ever measure that? Fortunately, the delta-m-squared point mentioned means that theory does give us a theoretical lower bound for the mass of the heaviest neutrino flavour. We know the rate of oscillation, so we know that the largest delta-m-squared has to be at least approx (0.05eV)^2. And so the heaviest type of neutrino has to be at least approx 0.05eV. If we carry out an experiment with a sensitivity capable of assessing the mass of neutrinos in that range, provided it addresses all flavours, then either we will learn the mass of the neutrino - well the heaviest kind at least. Or we will have proved that something is wrong with our theories. I hope the new experiment being carried out has that sensitivity. I asked someone working on that experiment if it does, but didn't get an answer.
What's going on with these extensions to the standard model you read about on wikipedia? Are any of them widely popular, or are they the purview of only a handful of physicists.
My favorite is one that wouldn't be counted in your hundreds. Neutrinos don't have mass--they can't because they travel at c. They are elliptically polarized photons that weakly interact with matter. They appear to oscillate because of these interactions with matter.
How can we be sure that the math we have come up with for neutrino oscillation being correlated to the difference of their mass states actually corresponds to reality? Maybe our assumption that neutrinos must have mass in order to experience time so as to be able to oscillate is just wrong. And if neutrinos actually DO have mass, it should be possible to reverse their handedness by swinging them around a black hole or even a near-maximum mass neutron star. If this happens, do you get a sterile neutrino or an antineutrino?
i've been wondering: wouldn't it be possible that what we see as oscillations actually stems from interactions the neutrinos undergo on their way, thus opening the possibility for them to be massless again. if they however indeed have to have a mass, then why is it that we only ever seem to detect neutrinos that travel negligibly close to the speed or light, even from distant supernovae?
I've read that we can detect neutrinos from neutrino generating sources that we make in the lab, and they're a lot easier to detect than cosmic neutrinos. I'm not a physicist and I don't really know the implications. I assume these neutrinos caused by nuclear decays on Earth are lower energy and travelling significantly slower (keep in mind, 0.99c is much, much slower than 0.9999c in terms of energy of interactions). But anyway, nuclear decays are very energetic and explosive, and even large particles like alpha particles can be ejected very fast. Since neutrinos are at least a billion times smaller than a proton, I imagine they must be ejected extremely fast because of conservation of momentum.
Could neutrinos existed before space, mass, and energy? They don't interact with matter, could they be distorted by existing in a dimension that we don't understand yet, but being observed in the third?
If a particle has a mass, it cannot be only right- or left handed because then you can be faster than it and this changes it's chirality with respect to your reference frame, doesn't it?
If you are willing to entertain the neutrino being a fundamentally different particle that gets it's mass in a fundamentally different way are the assumptions behind the argument that oscillations require they have mass still assumed to be valid? Could the oscillations be fundamentally different and neutrino in fact have zero mass?
@JonBrase, mass oscillations require a statistically suitable environment: free neutrinos can because their mass is so low; bound quarks can because they have neighbors to borrow from. Charged leptons will statistically only be seen to decay.
@@steveschunk5702 So basically, because we only see neutrinos or quarks in highly relativistic environments? Would we see the same thing with charged leptons in a collider beam at energies >> m_tau , or is there more to it than that?
I would think that the oscillations would be: suppose e_1, e_2, e_3 are the three mass eigenstates, and the initial state is (a e_1 + b e_2 + 3 e_3), Then, I think the phases should be something like, exp(i t m * (some constant) ) where m is the mass of each of the 3 mass eigenstates? (Err... it might be more complicated than I’m imagining... might need to throw in something about Pauli matrices?) And then, uh... Hm. Wait, these probabilities, are they for going between flavor eigenstates, or between mass eigenstates?
Left handed neutrinos only interact via gravity and weak interactions, which makes them difficult to detect. They have extremely small masses. However, if right handed neutrinos exist, shouldn't they interact via gravity? or am I missing something?
Would there be changes in the neutrino oscillation probabilities if the particles were influenced by relativistic effects, in other words, would the oscillations be the same if the source moves towards a detector at relativistic speed?
@@drdca8263 Indeed. Same thing with light, which can have its wavelength changed depending on the relative motion of its source. Can neutrino oscillation be "redshifted"? And considering the particle has mass, how would the detection probabilities of each flavor change, if at all, because of relativistic effects? Could such anomalies help finding the exact masses of these particles?
IMHO the simplest explanation is that neutrinos are on the limit of measurable mass by human technology and as such genuinely oscillate in their mass like every other fundamental particle only the oscillation is more significant for them as a proportion of their average mass. Spin is either R or L, genuine and superluminal as calculated and this Majorana particle does not annihilate upon collision with its opposite spin neutrinos because not enough superluminal fundamental particles of which the neutrinos ( and all other fundamental particles) collide to be measurable ( like galaxies passing through each other without colliding ). Fewer neutrinos are produced than hypothesised and they collide more often and more dramatically due to the high relative mass of the long- lived elementary particles they collide with resulting in adequate numbers of superluminal fundamental particles colliding to cause the resulting mayhem and resulting short- lived particles seen in cloud chambers and neutron detectors.
Dear Fermilab, is there any chance you could sort the "Even Bananas" TH-cam playlist chronologically so that new viewers can watch all the videos in the order they came out?
Ignoring the near impossible task of estimating the number of anything in a star and weight to such a precision to be able to do something like that. There's a bigger problem that it's a Neutron star not Neutrino star.
@@ResandOuies "A Rapidly Cooling Neutron Star" James M. Lattimer Department of Physics and Astronomy, Stony Brook University, ... Astrophysicists have found the first direct evidence for the fastest neutrino-emission mechanism by which neutron stars can cool. ... In a newly born neutron star, neutrinos are temporarily trapped in the opaque stellar core, but they diffuse out in a matter of seconds, leaving most of their energy to heat the matter in the core to more than 500 billion kelvin. Over the next million years, the star mainly cools by emitting more neutrinos. ..."
Right-handed neutrinos does have an appeal to it - we know that dark matter is essentially something that only interacts via gravity, which is basically what's being described. We've also been looking for what exactly dark matter is. Maybe it's just a bunch of right handed neutrinos that refuse to interact with anything except gravity?
For your information - a month and a half ago an interesting paper appeared, which completely revealed all the secrets of neutrinos: "Direct derivation of the neutrino mass"
Until someone could explain to me the relationship between the neutrino and DNA… because this is what it is all about… the mass is related to the information that it is carrying, and impacting us all every second starting from our genetic imprinting.
I've been told that neutrinos are not massive enough to explain dark matter despite how very many there are. But maybe the much more massive right-handed neutrinos could be dark matter?
it's not that the mass doesn't work out, it's the speed. Even very cold light neutrinos would have speeds way above the escape velocity of galaxies. RH neutrinos were posited in the 80s, which is fine for particle physics, but I think the cosmologist may have ruled them out, but idk.
I have heard that neutrinos are their own anti-particle. I assume this comes from observation of mutual annihilation. If such an even has been observed, would not the energy released tell us about the mass?
We don't know if they are their own anti-particle (aka a Majorana fermion) yet, but we are looking for signs of that "mutual annihilation" you mentioned, specifically by looking for a rare form of double beta decay. Beta decay releases either an electron or positron and an associated anti-neutrino/neutrino. If they are Majorana fermions, then some of the time those double beta decays will be neutrinoless and this affects the energy distribution to the outgoing beta particle which can be measured. If we can then observe enough events to measure the rate of this neutrinoless double beta decay that will tell us something about the neutrino mass.
@@atticmuse3749 double beta decay neutrinos are off shell, so their mass is wrong anyway. All the electrons tell you is the difference in energy of the nuclear states, minus some tiny recoil energy of the nucleus.
@@DrDeuteron my understanding is that the rate of neutrinoless double beta decay is related to neutrino mass, but I do not know the exact details. And what I meant is that based on the energies of the two electrons emitted, you can tell whether they come from a standard double beta decay or a neutrinoless one.
OK but something seems circular here. In what way would these hypothetical right-handed neutrinos be "heavier" than the left-handed ones, if this discrepancy is an explanation for how neutrinos have mass at all?
I believe particles get their mass because they contain energy, and are charged. This weak charge interacts with weak EM fields. The particles experience a resistance to all the weak EM fields (all wavelengths of light not just the Higgs) particles are bathed within when they move. It explains why when a proton is accelerated it increases in mass, which is a resistance to motion. The faster it travels through all the EM fields produced by all the bodies in the universe, the more mass or resistance it experience. According to measurements of the CMB when it's used as a standard of rest, our galaxy is moving about 1,370,000 mi/h towards what's called the great attractor. Our solar system is orbiting the center of the galaxy at roughly 536,000 mi/h while it recedes away from the central black hole at around 900,000 mi/h. The Earth orbits the sun at about 97,000 mi/h while at the equator it spins on it's axis at roughly 1,000 mi/h. I believe all the energy contained inside matter, moving through countless weak EM fields striking matter from every direction is what produces the resistance called mass. It's not just one Higgs field causing the resistance, but all of the energy fields put together.
Given how difficult it is to analyze particles without interfering with them, then I always remain a bit skeptical given mankind's history of theories don't exactly have a good track record of being right. I mean, particle physics is still relatively new. Give it another five-hundred years or so, and we'll probably be looking back at how our premature conclusions led to misconceptions. It's happened before anyway. Such an example is phlogiston.
If super heavy right hand neutrinos exist, how would they get made? The missing mass should be detectable in any process that makes neutrinos, shouldn't it?
"IF" modern science is correct that energy cannot be created nor destroyed, (one of the foundations of physics), then one would naturally assume the energy needed to make a neutrino would have to come from somewhere.
Energy and mass can be exchanged; a down quark has a mass of 5 MeV, and decays into an up quark with 2 MeV, and a W boson with a mass of 80 GeV, and that boson decays into an electron (.5 MeV) and a neutrino (idfk, but it’s low). The math ain’t mathin’, but, though mass isn’t, kinetic energy is conserved. A right handed neutrino with an incredibly high mass would just be moving (comparatively) slowly. That’s why a photon (massless) can decay into (massive) leptons. Oh, that’s also kind of the whole point of the E=mc^2 thing, but whatever.
Let's turn that around: why would the Standard Model have 3 flavor generations? So that neutrinos would have mass. 😸And thus far it seems they may break chirality a lot more than the quark sector, perhaps explaining matter/antimatter asymmetry. Having right handed neutrinos would make them more like the other fields, and if sterile they would be dark matter candidates - never mind that without axions we would add more finetuning to the already observed 10^-4 - 10^-6 of the Standard model. Let's go for the whole monty! 🙀
The first couple video cuts between Dr. Duffy and Dr. Machado felt a little strange. Her voice came back in before the transition started and it was a bit distracting. Otherwise, this was great. Neutrinos are such neat, weird little particles!
For these mysteries, the solution is always dependent on experimental data. Newton worked just fine (although there were some misgivings from the beginning) until the experimental data showed a problem. Newton still works fine for the most part which is amazing when you think about it. In order or us to make progress in physics we need better tools and better data. I think a lot of questions will be answered when we can use gravity like we use light. However, that may not solve all the problems. What using gravity will do is give us new questions, one we don't know to ask, that may give us insight into answers that, right now, are beyond our reach.
Dark matter is axions that are right-handed neutrinos? Virtual photons with some mass are right-handed neutrinos? Electrons are right-handed neutrinos?
but you can't make them in a mass states, since the weak interaction deals with flavor states. I look at it like birefrignet crystals, there are two polarizations(ordinary and extraordinary) that propagate with fixed index of refraction (like a mass, sort of)...but if we only have polarizers that see chocolate = (e+o) and vanilla = (e-o), the we're going to see flavor oscillations when we send chocolate into the crystal.
@@DrDeuteron I'm currently not well-versed in the weak interaction, but oscillation doesn't seem to equal just a _superposition_ of different basis states... there's something more...
thinking about it, when lets say electron neutrinos νᵉ interacts weakly, could the momentum they impart (assuming all prepared in the same way) be different depending on the mass state projected at that point (which is tiny, I know)?
@@GeoffryGifari it’s best just to read the Wikipedia page on how an initial flavor state propagates. The superposition is complex, so each mass state has its phase propagating at different spatial rates, so as the phases change, the mass states add up to different mixtures of flavor states. Without the complex numbers, it doesn’t work, so if your imagining a real linear combination, it’s not going to seem like enough.
'Speed of light': 'Speed' is distance divided by time, 'distance' being 2 points in space with space between those 2 points. Modern science also claims that 'space' can contract, expand and warp and that 'time' can vary and warp. How can the speed of light be constant across the vast universe 'if' space and/or time are contracting, expanding, varying or warping? And, what exactly is 'space' that it can contract, expand and warp? What exactly is 'time' that it can vary and warp? * These are not questions for you to answer here, just questions I have that I believe need answers to.
@@charlesbrightman4237imagine a chihuahua that always runs at 5mph. if you put him on a moving sidewalk, he still runs at 5mph but he doesn't move at 5mph relative to the buildings. i think light and spacetime can work like that. is this the river model of relativity? no expert but this may be a part of the story
The 'speed of light' is just how fast things move when there's nothing slowing them down. Particles are waves; they can't not move. The ones that have mass are slowed down by bumping into the Higgs field
@@nmarbletoe8210Sounds like Galilean relativity, where there's no max speed. Light is a Chihuahua that runs at 5 mph relative to the sidewalk, 5 mph relative to the buildings, and 5 mph relative to someone running the other direction. It's an absurd notion that no one would believe if scientists hadn't spent so many years verifying it over and over again. Something about the sidewalk, or about the Chihuahua, or about the act of observing it, is not as simple as it seems
I’m no scientist, but if there’s all this dark matter that we know is there but we can’t see, and neutrinos have mass that we can’t see…do you know where I am going with this?
Dark matter clusters around galaxies. The neutrino won't fit because it is so light, it would just keep going through empty space. But maybe the right hand neutrino, if slow, might fit (from what I understand).
This is a good idea! - this has been a proposed possible solution to dark matter for a few decades. You should look into this if you're interested! PBS Space Time did a great video about it. I'll see if I can find the link for you.
@@harrkev Dark matter probably does not actually exist. The singular big bang theory is a fairy tale for various reasons, the CMBR from the supposed bang should be long gone by now, and the red shift observations have a more normal already known physics explanation, no dark energy nor dark matter needed.
Neutrinos and dark matter is an excellent topic as there are some overlapping ideas. We discussed this in a previous episode: th-cam.com/video/RnUOR1p69cY/w-d-xo.html
@@harrkev this is good thinking too. There was another theory I read about, where there might be a gravitational vortex around the galaxy, at the extreme edges of the gravitational pull of galaxy clusters, curving space-time and preventing these neutrinos from leaving their local group. 🤷♂️ It was just a theory, but AFAIK (I'm an amateur too), there is still no concrete enough evidence (six sigma+ statistical confidence) that we can definitively rule out some of these theories without more support at the moment.
I look at the problem in a different way. A neutrino travels at the speed of light. Therefore it cannot have mass. So the hypothesis that led you to conclude that it has mass must be wrong. Richard
Three-dimensional space appears to be an expression of two-dimensional space. Maybe Buddhist iconography has it more correct. 2-dimensional white matter and dark matter (absolute hot/absolute cold) at equilibrium, they may bind perpendicularly to create a dynamic 2-dimensional field that results in a 3-dimensional space. Angular momentum has to be initiated at a fundamental level.
Neutrinos and dark matter is an excellent topic as there are some overlapping ideas. We discussed this in a previous episode: th-cam.com/video/RnUOR1p69cY/w-d-xo.html
@@fermilab : Thanks for the link. That previous video means a little more now, in hindsight. It used the term "sterile neutrino" and didn't mention the right-handedness. Perhaps in a future video, you'll discuss the attempts to tweak the neutrino model to allow sterile neutrinos to account for the bulk of dark matter.
Corrections: The diagram at 2:43 should show an electron antineutrino not a muon antineutrino. Additionally at 3:05 the first number should be 0.26eV.
Thanks!
Can you tell us initial assumptions (contrary of what you explain in the video) are coming from, i.e. why are neutrinos supposed to be massless and NEVER interacting?
I'm over 30yo and I always heard that they probably have a very tiny mass and they barely interact with the matter, but hearing that the mass is supposed to be ZERO and they NEVER interact is a fresh concept to me!
Where exactly does it come from? What's the reason behind expecting them to NOT have a mass, nor interaction?
Hypothesis, for the explanation of neutrino mass.
Not Theories.
Then why don't you fix it and repost?
Instructions unclear, my bananas are now all chirally right handed and glowing neutrino color.
Isn't invisible green a great color? It works very well for sleeping furiously also.
El. Psy. Congroo.
This Reddit meme is really boring, stop doing it
I'm curious about the meaning of this comment...🤔
@@juliacoala I think it exists as both a joke and an innuendo until the waveform collapses....
Neutrino physics is the final frontier (for now) in particle physics. It is bound to result in brand new physics sooner or later. Hats off to all you brilliant scientists working on the mysteries of the universe!
Please never stop Even Bananas! I hope Prof Don doesn't mind, but this is becoming better and better with each video
We can be spoiled and have both! That would make me really happy 😊
For those who don't understand why oscillation necessarily implies mass, it's because they experience time, and massless particles do not experience time.
'massless particles do not experience time' - I've heard this aplenty for photons, yet it still makes my head spin. Like what does that even MEAN?! How do they travel if they don't experience time? Would a photon emitted at the beginning of the universe that didn't get absorbed by anything just 'see' the universe's end as soon as it was created? But in that case why wouldn't every other photon 'see' the end as soon as it's created? What's it like to 'not experience time', yet still be doing stuff that takes time?
@@ArawnOfAnnwn It's important to keep in mind what is meant by time. In physics, it refers to what a clock is showing. So what is a clock then? It's essentially any well-defined, measurable, periodic change. A second is defined as being a specific number of energy level transition changes of electrons in a Cesium 133 atom, for example (it's approximately 9.1 billion).
So then if you have the right equipment to detect those changes, when you see that the 9.1 billion changes have happened, you know that 1 second has passed. However, if that Cesium atom begins to move relative to you, Special Relativity says that the amount of time it appears to you to take for those 9.1 billion changes in that moving Cesium atom to happen begins to grow. The closer it gets to light speed, the slower they appear to happen. If it was possible to accelerate that atom all the way to light speed then the changes would appear to you to stop happening entirely. If a measurement device was moving along with the Cesium atom, it would record the changes as happening at the same pace they appeared to be happening to you before the atom started moving. But that's because that Cesium atom is not moving relative to that measurement device. However, because the measurement device is moving relative to you, you wouldn't see it changing for the same reason you didn't see the Cesium atom changing (time dilation).
In reality, nothing with mass can reach light speed so it wouldn't be possible for the Cesium atom to seem to completely stop those changes. But they will appear to slow way down as it gets closer and closer and experiments have measured and confirmed that this phenomenon does happen. Indeed, GPS satellites have to take gravitational time dilation into account because time also appears to pass more slowly the closer something is to a gravity source and so clocks on Earth tick slower from the perspective of the satellites orbiting up above Earth than the clocks on the satellites themselves do.
@@ArawnOfAnnwn Actually, massless particles also don't experience any distance either. So from their point of view they travel 0 distance in 0 time, which works out just fine.
@@Boopers So everything just comes at them? No, cos that would imply both distance and time still. So everything that they're ever going to interact with has already hit them as soon as they were created? Said interaction absorbs them, so did they ever exist to begin with? Do they even experience their own existence, when they don't experience any time of said existence? Just what is their existence like?!
@@ArawnOfAnnwn You can interpret it this way: Due to length contraption, which compresses length towards zero for an observer as they approach the speed of light, the perception of any finite distance in the direction of motion for a light speed observer (which massless things like photoons will be) is zero. From the perspective of a photon the universe is compressed into a perfectly flat sheet they are imbeded in, so they are literally always in all the places their trajectory will move through.
Please never stop with Even Bananas
neutrino mystery assures endless research. She said in another video that the more we learn, the more questions will appear
Also since right handed neutrinos would be very heavy and would'nt interact in any way but gravitationally, that makes them theoretical candidates for dark matter too
dark matter made of neutrinos would have been hot, the dark matter is cold
I am from India Your videos explain science in the most understandable way, thank you very much.
Thnks, Fermilab! Keep on doing cool videos, and kudos to Kirsty and Pedro!
I'm unsure as to why anyone would have assumed that neutrinos had 0 mass. Every other fermion has mass. Why would neutrinos be so special?
A refreshing, information-dense video on neutrinos. What a wonderful treat.
Happy to see you back, Kirsty.
Nice Explanation
Here's what I think is wild: During matter-antimatter annihilation, with a large proportion of the energy produced taking the form of neutrinos.
Hold the phone! The Higgs mechanism comes from breaking chiral symmetry? Is there a way to grasp this as a lay person without formal instruction in QFT?
Go read up on chiral symmetry on Wikipedia, that's a good start.
kind of? It definitely makes more sense to me than it used to, but imo there's an upper limit on how "familiar" some topics within particle/astro physics can be. Like yeah, you can see dozens of models and come up with hundreds of metaphors and crunch mountains of numbers, but at the end of the day it's still always going to _kinnddaaa_ seem like black magic 🤷♂
(and I think that's neat; so much of theoretical physics deals with topics that are inherently unfathomable for humans... yet we dare to fathom anyway!)
If the mass of sterile neutrinos is so large, like very close to the GUT scale, do we have any chance at all to detect them?
I'd never heard of Ettore Majorana before today, interested to learn more about him esp. considering the praise he received and who said it. Another great video. :)
Are neutrinos “important” in everyday particle interactions? I.e. is their miniscule mass and difficulty in detection indicative of a very miniscule but important effect, or important for our understanding but largely irrelevant effect?
(Example might help: detecting proton decay might be very interesting and helpful for our understanding, but the difficulty in detection is because it’s so rare as to be irrelevant for any experiment that isn’t itself trying to detect proton decay)
They are important in supernova explosions. Without the interaction of the neutrinos (i like to call it neutrino wind) the outer shells would just fall back on the core and the higher chemical elements generated in the fusion in the stars and in the supernova explosion could not leave the star remnants. Without them life as we know it would not be possible. Not to forget that without neutrinos a lot of the nuclear decays would not work.
@@Techmagus76 that’s fascinating!
That’s actually a really good example of what I was asking about, thanks for the answer!!! :)
If we are speaking about Majorana fermions, are we saying that these right handed heavier siblings may be Neutralinos? (which is one the coolest "and coldest" dark matter candidate by the way). Description actually fits Neutralinos but I happen to remember Majorana fermions instead of Dirac fermions to have mixed chiralities as they are their also own anti-particle.
Wait why are these videos actually so good
Always enjoy your videos.
Hey hey hey!
Have anyone noticed the Fermilab bulding in the Netflix "Three Body Problem" new series?
It's in the third episode, at 41:00 when the game AI does an exposition to Jin and Rooney and the Follower advances time.
Or is it?
👀
Neutrinos having mass? Thats bananas! 😛
(Sorry, had to be, just came home from work and I need to unwind a bit.)
What if neutrinos are rotating not just in the 3 position dimensions but also in the 4th time dimension? If that were the case, would we observe as a small mass change would actually be the speed of time oscillating.
I keep wondering if there is some property or field they interact with such that they don't actually experience time and really are massless, but because of how we measure, (or similar) they only appear to oscillate.
What do you mean by “speed of time”? This doesn’t seem to immediately offer a meaning, other than “1” (1 second per second).
I guess if you fixed a coordinate system you could talk about time per proper time, or proper time per time?
What do you mean by “speed of time”?
Would right-hand (heavy) neutrinos somehow interact with left-hand neutrinos? And by having mass, would they also undergo some change in time, an oscillation or such? Oh, and should neutrino (the ones we know, left-handed) oscillation actually include some particle interaction, some exchange of hypothetic other particles between neutrinos of different flavors, which is not detected or detectable right now?
Very clear. Thankyou!
I find it rather amazing that during the collision of neutron stars, the hypernova releases much of its energy in the neutrinoes that drives the Rapid process synthesis of heavy elements, IIRC.
Is the diagram at 2:45 wrong? On the bottom right it looks like the symbol for a Muon Anti-Neutrino, but Beta Decay emits an Electron (Anti)Neutrino, not a Muon Neutrino. Anyone want to chime in, let me know
Thanks for catching that! You are correct the diagram should show an electron antineutrino.
@@fermilab Thank you for the reply!! Small detail but I only realized it because I learned from the best (FermiLab) :)
They would have to have longer wavelengths (-14 range) to be massless, like a 100MeV+ gamma ray. Too much energy in a neutrino. The permeability of the Higgs Field is what, 127-ish?
Always fascinating!
with disturbances between energies (which spread in forward spirals),
vortices arise, which make these energies appear as matter,
and in energy fields such as the Higgs, a torque is exerted on these vortices,
this torque creates an apparent mass, a quantitative gravity,
It's weird that it would be surprising that neutrinos interact, since how could they be created if they don't interact at some level? Just reverse that reaction, and it's an interaction.
They aren't made from particles that don't interact. You seem to imply they are made from themselves, and that doesn't work.
@@thekaxmax I'm saying, some interaction creates them, so the reverse of that interaction should also be possible.
@@while_coyoteYes, I also thought that comment was odd!
(I think the “if the interaction producing them is possible, then the interaction absorbing them should also be possible” thing should follow from the Lagrangian density being self-adjoint. Like, if there’s a term that has a creation operator for the neutrino, the Hermitian conjugate, which should include the annihilation operator, should also be included)
The audio has issues, look into that as well :))
not exactly physics-related but your eye makeup (whatever that's called, idk lol) looks really cool!!
My understanding of electron mass is that it's caused by the Higgs Mechanism, which causes electrons to rapidly oscillate between left and right handedness.
My question is, could neutrino mass come from the mechanism that causes them to rapidly oscillate flavor?
F=ma and E=mc. If it exists, it has mass. The question is, what kind of mass? Atomic mass or Radiant Energy mass as in an electrical charge.
A photon has mass in that it has an electrical charge. It has mass in that it has a wavelength. Mass is Space and Space is 3 dimensions. Or in the case of photons, one dimension which is its wavelength.
E=mc. If it has an electrical charge, it has mass. Atomic mass if the acceleration value is < c. Otherwise Radiant energy if = c.
First you need to understand what mass is which is just energy.
What you should be asking is; what is mass at absolute zero aka. Zero Acceleration/No energy.
mass doesn't exist, it's always rest mass
the rest energy that you have if you got slower than c
Thanks for the video. With 100 theories you mean 100 hypothesis right?? (because we are not able to test it?)
You have hit on a very important "domain lexicon" confusion in the modern world.
Somebody in the hard sciences will have a very different definition of what "theory" means compared to the general public.
To the general public, the word "theory" mostly means an unproven verbal explanation for why something has happened.
As you point out, in the hard sciences this is considered merely a hypothesis.
Then the math fun starts.
The next step is usually to try to find mathematical relationships that predictively describe this hypothesis.
You are now at the "model" stage.
If your model survives comparing outputs with other well tested models, theories, and observations, only then does it get to the status of "theory" in the hard sciences.
Unfortunately, this distinction is incredibly difficult to explain to most people.
no. particle physics isn't high school science class.
@@NullHand thanks for the extremely clear explanation. Really helps!!!
A hypothesis is a guess that can be tested with an experiment. A theory is a model for a phenomenon. They're completely different categorically. A theory that doesn't predict anything can still be a theory, just a bad one.
what is being done in the experimental side of things to solve this question?
Would conservation of lepton number imply that an electron is something like a neutrino with an electric field attached?
I understand why Dirac spinors have a left- and right-chiral Weyl spinor because of non-equivalent SL(2, C) representations, but I still don't understand why the weak force only binds to left-handed fermions. Maybe one day.
Neutrinos have mass. Or the theories from which we deduced that are wrong. It wouldn't be the first time it turned out the latter was the explanation of an anomaly in physics.
We make experiments to try and assess the mass of neutrinos. And keep on reducing the upper bound to the neutrino mass. But upper bounds for the mass aren't as helpful as lower bounds. What if the neutrino weighs 0.00000000000000000000000000001eV or something, can we ever measure that? Fortunately, the delta-m-squared point mentioned means that theory does give us a theoretical lower bound for the mass of the heaviest neutrino flavour. We know the rate of oscillation, so we know that the largest delta-m-squared has to be at least approx (0.05eV)^2. And so the heaviest type of neutrino has to be at least approx 0.05eV. If we carry out an experiment with a sensitivity capable of assessing the mass of neutrinos in that range, provided it addresses all flavours, then either we will learn the mass of the neutrino - well the heaviest kind at least. Or we will have proved that something is wrong with our theories. I hope the new experiment being carried out has that sensitivity. I asked someone working on that experiment if it does, but didn't get an answer.
What's going on with these extensions to the standard model you read about on wikipedia? Are any of them widely popular, or are they the purview of only a handful of physicists.
My favorite is one that wouldn't be counted in your hundreds. Neutrinos don't have mass--they can't because they travel at c. They are elliptically polarized photons that weakly interact with matter. They appear to oscillate because of these interactions with matter.
How can we be sure that the math we have come up with for neutrino oscillation being correlated to the difference of their mass states actually corresponds to reality? Maybe our assumption that neutrinos must have mass in order to experience time so as to be able to oscillate is just wrong.
And if neutrinos actually DO have mass, it should be possible to reverse their handedness by swinging them around a black hole or even a near-maximum mass neutron star. If this happens, do you get a sterile neutrino or an antineutrino?
Thanks for the informative video! Is there something wrong with the lighting on the left side of your face (right side of the frame)?
i've been wondering: wouldn't it be possible that what we see as oscillations actually stems from interactions the neutrinos undergo on their way, thus opening the possibility for them to be massless again.
if they however indeed have to have a mass, then why is it that we only ever seem to detect neutrinos that travel negligibly close to the speed or light, even from distant supernovae?
inertia maybe?(the first idea sounds credible actually)
I've read that we can detect neutrinos from neutrino generating sources that we make in the lab, and they're a lot easier to detect than cosmic neutrinos. I'm not a physicist and I don't really know the implications. I assume these neutrinos caused by nuclear decays on Earth are lower energy and travelling significantly slower (keep in mind, 0.99c is much, much slower than 0.9999c in terms of energy of interactions). But anyway, nuclear decays are very energetic and explosive, and even large particles like alpha particles can be ejected very fast. Since neutrinos are at least a billion times smaller than a proton, I imagine they must be ejected extremely fast because of conservation of momentum.
Could neutrinos existed before space, mass, and energy? They don't interact with matter, could they be distorted by existing in a dimension that we don't understand yet, but being observed in the third?
If a particle has a mass, it cannot be only right- or left handed because then you can be faster than it and this changes it's chirality with respect to your reference frame, doesn't it?
If you are willing to entertain the neutrino being a fundamentally different particle that gets it's mass in a fundamentally different way are the assumptions behind the argument that oscillations require they have mass still assumed to be valid? Could the oscillations be fundamentally different and neutrino in fact have zero mass?
Here's an interesting question: Why do quarks and neutrinos have mixing between mass and flavor states, but leptons have a 1-to-1 correspondence?
@JonBrase, mass oscillations require a statistically suitable environment: free neutrinos can because their mass is so low; bound quarks can because they have neighbors to borrow from. Charged leptons will statistically only be seen to decay.
@@steveschunk5702 So basically, because we only see neutrinos or quarks in highly relativistic environments? Would we see the same thing with charged leptons in a collider beam at energies >> m_tau , or is there more to it than that?
Can things have mass, which is not positive number? Can mass be negative, complex or otherwise weird?
Are neutrinos affected by the warped space around a black hole? Might the effects of such hint at aspects of quantum gravity?
any energy in the vacuum is getting aten by black holes
Thought oscillation are in one direction from heavy to lighter?
I would think that the oscillations would be:
suppose e_1, e_2, e_3 are the three mass eigenstates, and the initial state is (a e_1 + b e_2 + 3 e_3),
Then, I think the phases should be something like, exp(i t m * (some constant) ) where m is the mass of each of the 3 mass eigenstates?
(Err... it might be more complicated than I’m imagining... might need to throw in something about Pauli matrices?)
And then, uh...
Hm.
Wait, these probabilities, are they for going between flavor eigenstates, or between mass eigenstates?
I don't know which theory is my favourite,
because I've only heard 3...out of the "over a hundred".
Left handed neutrinos only interact via gravity and weak interactions, which makes them difficult to detect. They have extremely small masses. However, if right handed neutrinos exist, shouldn't they interact via gravity? or am I missing something?
Would there be changes in the neutrino oscillation probabilities if the particles were influenced by relativistic effects, in other words, would the oscillations be the same if the source moves towards a detector at relativistic speed?
I believe the neutrinos are already moving at a relativistic speed compared to the system from which they are emitted?
@@drdca8263 Indeed. Same thing with light, which can have its wavelength changed depending on the relative motion of its source. Can neutrino oscillation be "redshifted"? And considering the particle has mass, how would the detection probabilities of each flavor change, if at all, because of relativistic effects?
Could such anomalies help finding the exact masses of these particles?
Can another scalar field that interacts with Neutrinos be ruled out?
IMHO the simplest explanation is that neutrinos are on the limit of measurable mass by human technology and as such genuinely oscillate in their mass like every other fundamental particle only the oscillation is more significant for them as a proportion of their average mass. Spin is either R or L, genuine and superluminal as calculated and this Majorana particle does not annihilate upon collision with its opposite spin neutrinos because not enough superluminal fundamental particles of which the neutrinos ( and all other fundamental particles) collide to be measurable ( like galaxies passing through each other without colliding ).
Fewer neutrinos are produced than hypothesised and they collide more often and more dramatically due to the high relative mass of the long- lived elementary particles they collide with resulting in adequate numbers of superluminal fundamental particles colliding to cause the resulting mayhem and resulting short- lived particles seen in cloud chambers and neutron detectors.
Shouldn't there be an energy deficit in the overall reaction that matches the mass/energy of the hypothesized right-handed neutrino?
Shouldn't you use "100s of hypotheses" instead of "theories"?
Dear Fermilab, is there any chance you could sort the "Even Bananas" TH-cam playlist chronologically so that new viewers can watch all the videos in the order they came out?
So if the right-handed neutrino could be a very heavy neutrino that has no or next to no interaction with anything, could it be dark matter?
Could right hand nutrino be dark matter of they r very massive?
Why are the neutrinos named after electron tau etc.
Could you approximate a neutrino mass by measuring the gravitational effects of a neutron star?
Ignoring the near impossible task of estimating the number of anything in a star and weight to such a precision to be able to do something like that. There's a bigger problem that it's a Neutron star not Neutrino star.
@@ResandOuies "A Rapidly Cooling Neutron Star" James M. Lattimer Department of Physics and Astronomy, Stony Brook University,
...
Astrophysicists have found the first direct evidence for the fastest neutrino-emission mechanism by which neutron stars can cool. ... In a newly born neutron star, neutrinos are temporarily trapped in the opaque stellar core, but they diffuse out in a matter of seconds, leaving most of their energy to heat the matter in the core to more than 500 billion kelvin. Over the next million years, the star mainly cools by emitting more neutrinos. ..."
Right-handed neutrinos does have an appeal to it - we know that dark matter is essentially something that only interacts via gravity, which is basically what's being described. We've also been looking for what exactly dark matter is. Maybe it's just a bunch of right handed neutrinos that refuse to interact with anything except gravity?
For your information - a month and a half ago an interesting paper appeared, which completely revealed all the secrets of neutrinos: "Direct derivation of the neutrino mass"
Until someone could explain to me the relationship between the neutrino and DNA… because this is what it is all about… the mass is related to the information that it is carrying, and impacting us all every second starting from our genetic imprinting.
I've been told that neutrinos are not massive enough to explain dark matter despite how very many there are. But maybe the much more massive right-handed neutrinos could be dark matter?
it's not that the mass doesn't work out, it's the speed. Even very cold light neutrinos would have speeds way above the escape velocity of galaxies.
RH neutrinos were posited in the 80s, which is fine for particle physics, but I think the cosmologist may have ruled them out, but idk.
@@DrDeuteronThank you. It makes sense to me, now that you have clarified it.
I have heard that neutrinos are their own anti-particle. I assume this comes from observation of mutual annihilation. If such an even has been observed, would not the energy released tell us about the mass?
We don't know if they are their own anti-particle (aka a Majorana fermion) yet, but we are looking for signs of that "mutual annihilation" you mentioned, specifically by looking for a rare form of double beta decay. Beta decay releases either an electron or positron and an associated anti-neutrino/neutrino. If they are Majorana fermions, then some of the time those double beta decays will be neutrinoless and this affects the energy distribution to the outgoing beta particle which can be measured. If we can then observe enough events to measure the rate of this neutrinoless double beta decay that will tell us something about the neutrino mass.
how do you measure nu + nu --> nothing, since you need a bazillion neutrinos and 10^27-ish target atoms to detect one per week?
@@DrDeuteron You measure the energies of the electrons that are emitted in the double beta decay.
@@atticmuse3749 double beta decay neutrinos are off shell, so their mass is wrong anyway. All the electrons tell you is the difference in energy of the nuclear states, minus some tiny recoil energy of the nucleus.
@@DrDeuteron my understanding is that the rate of neutrinoless double beta decay is related to neutrino mass, but I do not know the exact details. And what I meant is that based on the energies of the two electrons emitted, you can tell whether they come from a standard double beta decay or a neutrinoless one.
Did Machado mean "Higgs _Field"_ when he said at 3:58 that particles get mass by interacting with the "Higgs Boson"?
yes.
Fascinating
OK but something seems circular here. In what way would these hypothetical right-handed neutrinos be "heavier" than the left-handed ones, if this discrepancy is an explanation for how neutrinos have mass at all?
I believe particles get their mass because they contain energy, and are charged. This weak charge interacts with weak EM fields. The particles experience a resistance to all the weak EM fields (all wavelengths of light not just the Higgs) particles are bathed within when they move. It explains why when a proton is accelerated it increases in mass, which is a resistance to motion. The faster it travels through all the EM fields produced by all the bodies in the universe, the more mass or resistance it experience.
According to measurements of the CMB when it's used as a standard of rest, our galaxy is moving about 1,370,000 mi/h towards what's called the great attractor. Our solar system is orbiting the center of the galaxy at roughly 536,000 mi/h while it recedes away from the central black hole at around 900,000 mi/h. The Earth orbits the sun at about 97,000 mi/h while at the equator it spins on it's axis at roughly 1,000 mi/h.
I believe all the energy contained inside matter, moving through countless weak EM fields striking matter from every direction is what produces the resistance called mass. It's not just one Higgs field causing the resistance, but all of the energy fields put together.
that completely violates special relativity, where "moving" is meaningless.
Given how difficult it is to analyze particles without interfering with them, then I always remain a bit skeptical given mankind's history of theories don't exactly have a good track record of being right.
I mean, particle physics is still relatively new. Give it another five-hundred years or so, and we'll probably be looking back at how our premature conclusions led to misconceptions. It's happened before anyway. Such an example is phlogiston.
Neutrinos operate differently than anything else... We do not have the mathematics to explain them !!
If super heavy right hand neutrinos exist, how would they get made? The missing mass should be detectable in any process that makes neutrinos, shouldn't it?
"IF" modern science is correct that energy cannot be created nor destroyed, (one of the foundations of physics), then one would naturally assume the energy needed to make a neutrino would have to come from somewhere.
Energy and mass can be exchanged; a down quark has a mass of 5 MeV, and decays into an up quark with 2 MeV, and a W boson with a mass of 80 GeV, and that boson decays into an electron (.5 MeV) and a neutrino (idfk, but it’s low). The math ain’t mathin’, but, though mass isn’t, kinetic energy is conserved. A right handed neutrino with an incredibly high mass would just be moving (comparatively) slowly. That’s why a photon (massless) can decay into (massive) leptons.
Oh, that’s also kind of the whole point of the E=mc^2 thing, but whatever.
Let's turn that around: why would the Standard Model have 3 flavor generations? So that neutrinos would have mass. 😸And thus far it seems they may break chirality a lot more than the quark sector, perhaps explaining matter/antimatter asymmetry. Having right handed neutrinos would make them more like the other fields, and if sterile they would be dark matter candidates - never mind that without axions we would add more finetuning to the already observed 10^-4 - 10^-6 of the Standard model. Let's go for the whole monty! 🙀
Maybe neutrino masses aren't that different from 'all the other particles'? Maybe we're only looking at some of 'all the other particles'?
Nice motivation to do something, to break illusion that all is invented many years ago.
The first couple video cuts between Dr. Duffy and Dr. Machado felt a little strange. Her voice came back in before the transition started and it was a bit distracting. Otherwise, this was great. Neutrinos are such neat, weird little particles!
0.26eV then 0.026eV. Which is it?
Yeah this video feels very sloppy
Thanks for catching that! The first number at 3:05 should be 0.26 eV.
Thanks for being responsive to feedback.
For these mysteries, the solution is always dependent on experimental data. Newton worked just fine (although there were some misgivings from the beginning) until the experimental data showed a problem. Newton still works fine for the most part which is amazing when you think about it. In order or us to make progress in physics we need better tools and better data. I think a lot of questions will be answered when we can use gravity like we use light. However, that may not solve all the problems. What using gravity will do is give us new questions, one we don't know to ask, that may give us insight into answers that, right now, are beyond our reach.
Dark matter is axions that are right-handed neutrinos? Virtual photons with some mass are right-handed neutrinos? Electrons are right-handed neutrinos?
When a neutrino is travelling in space, does it stay in the same mass state?
but you can't make them in a mass states, since the weak interaction deals with flavor states. I look at it like birefrignet crystals, there are two polarizations(ordinary and extraordinary) that propagate with fixed index of refraction (like a mass, sort of)...but if we only have polarizers that see chocolate = (e+o) and vanilla = (e-o), the we're going to see flavor oscillations when we send chocolate into the crystal.
@@DrDeuteron ah so can I say that a neutrino "settles" to a mass state a short while after being created in a flavor state?
@@DrDeuteron I'm currently not well-versed in the weak interaction, but oscillation doesn't seem to equal just a _superposition_ of different basis states... there's something more...
thinking about it, when lets say electron neutrinos νᵉ interacts weakly, could the momentum they impart (assuming all prepared in the same way) be different depending on the mass state projected at that point (which is tiny, I know)?
@@GeoffryGifari it’s best just to read the Wikipedia page on how an initial flavor state propagates. The superposition is complex, so each mass state has its phase propagating at different spatial rates, so as the phases change, the mass states add up to different mixtures of flavor states. Without the complex numbers, it doesn’t work, so if your imagining a real linear combination, it’s not going to seem like enough.
What mechanism accelerates neutrino at the speed of light?
'Speed of light': 'Speed' is distance divided by time, 'distance' being 2 points in space with space between those 2 points. Modern science also claims that 'space' can contract, expand and warp and that 'time' can vary and warp. How can the speed of light be constant across the vast universe 'if' space and/or time are contracting, expanding, varying or warping?
And, what exactly is 'space' that it can contract, expand and warp?
What exactly is 'time' that it can vary and warp?
* These are not questions for you to answer here, just questions I have that I believe need answers to.
@@charlesbrightman4237imagine a chihuahua that always runs at 5mph. if you put him on a moving sidewalk, he still runs at 5mph but he doesn't move at 5mph relative to the buildings. i think light and spacetime can work like that. is this the river model of relativity? no expert but this may be a part of the story
@@nmarbletoe8210 And yet:
What exactly is 'space' and what exactly is 'time'?
The 'speed of light' is just how fast things move when there's nothing slowing them down. Particles are waves; they can't not move. The ones that have mass are slowed down by bumping into the Higgs field
@@nmarbletoe8210Sounds like Galilean relativity, where there's no max speed. Light is a Chihuahua that runs at 5 mph relative to the sidewalk, 5 mph relative to the buildings, and 5 mph relative to someone running the other direction. It's an absurd notion that no one would believe if scientists hadn't spent so many years verifying it over and over again. Something about the sidewalk, or about the Chihuahua, or about the act of observing it, is not as simple as it seems
Neutrino Mass... let me explain. A long time ago, Neutrino Jesus was born...
I’m no scientist, but if there’s all this dark matter that we know is there but we can’t see, and neutrinos have mass that we can’t see…do you know where I am going with this?
Dark matter clusters around galaxies. The neutrino won't fit because it is so light, it would just keep going through empty space.
But maybe the right hand neutrino, if slow, might fit (from what I understand).
This is a good idea! - this has been a proposed possible solution to dark matter for a few decades.
You should look into this if you're interested! PBS Space Time did a great video about it. I'll see if I can find the link for you.
@@harrkev Dark matter probably does not actually exist. The singular big bang theory is a fairy tale for various reasons, the CMBR from the supposed bang should be long gone by now, and the red shift observations have a more normal already known physics explanation, no dark energy nor dark matter needed.
Neutrinos and dark matter is an excellent topic as there are some overlapping ideas. We discussed this in a previous episode: th-cam.com/video/RnUOR1p69cY/w-d-xo.html
@@harrkev this is good thinking too. There was another theory I read about, where there might be a gravitational vortex around the galaxy, at the extreme edges of the gravitational pull of galaxy clusters, curving space-time and preventing these neutrinos from leaving their local group. 🤷♂️
It was just a theory, but AFAIK (I'm an amateur too), there is still no concrete enough evidence (six sigma+ statistical confidence) that we can definitively rule out some of these theories without more support at the moment.
Maybe there's an oldtrino?
I look at the problem in a different way. A neutrino travels at the speed of light. Therefore it cannot have mass. So the hypothesis that led you to conclude that it has mass must be wrong. Richard
Three-dimensional space appears to be an expression of two-dimensional space. Maybe Buddhist iconography has it more correct. 2-dimensional white matter and dark matter (absolute hot/absolute cold) at equilibrium, they may bind perpendicularly to create a dynamic 2-dimensional field that results in a 3-dimensional space.
Angular momentum has to be initiated at a fundamental level.
🦋🇺🇸🧐I’m new so I’m still learning 😊🤫🤷🏼♀️
What about odd bananas?
And that is not breaking relativity? Because the neutrino velocity is c, and c is not reachable for any particle with mass.
100 theories means yours can't be considered wrong no matter how weird so still worth a paycheque.
In the maths, can you say neutrinos have infinitesimal mass? Nilpotent neutrinos? M^2 == 0, but M not == 0
M is not an operator. however, "ladder operators" in angular momentum are nilpotent.
Liked and shared.
My guess is that there are Three Higgs Bosons. One for normal matter, one for neutrinos, and one for Dark Matter.
Did the video mention the possibility that right-handed neutrinos are dark matter? If so, I missed it.
Neutrinos and dark matter is an excellent topic as there are some overlapping ideas. We discussed this in a previous episode: th-cam.com/video/RnUOR1p69cY/w-d-xo.html
@@fermilab : Thanks for the link. That previous video means a little more now, in hindsight. It used the term "sterile neutrino" and didn't mention the right-handedness.
Perhaps in a future video, you'll discuss the attempts to tweak the neutrino model to allow sterile neutrinos to account for the bulk of dark matter.
We want the guy back!!!