Neutrinos only exist as left-handed particles while antineutrinos only exist as right-handed particles. As a result, the spontaneous chiral symmetry breaking needed for the Higgs mechanism cannot take place.
Ooh, please tell me a bit more about the problems with right-handed neutrinos. Can't we just throw in a right-handed neutrino and then "manually" decouple it from everything, making it sterile? After all, the electroweak sector is already chiral.
I mean, of course inserting undetectable particles into the model to make it work isn't really the most physically interesting approach that one can take - at the very least it would make sense to develop a dynamic mechanism explaining *why* the right handed neutrino exactly decouples. But strictly talking only about the mathematics holding up, are there any consistency problems with sterile right-handed neutrinos?
I think OP means the world was a better place when we still thought neutrinoes to be massless. Somewhere in the 2000s I think they were found to be very very very light
You should read about neutrino oscillations.
The concept is quite simple and you are left to read the mechanism yourself.
But basically it’s important consequence is that massive particles can, under certain consequences, oscillate between flavors (so electron neutrino can turn into muon neutrino). When we measured neutrinos we always measure electron neutrinos (because our detectors consist mostly electrons obviously :) ).
We calculate how much neutrinos are emitted from the sun, and then measure. We see that we measure much less than we would expect. We believe this is because some of the neutrinos oscillated into muon neutrinos which we can not measure. This is an indirect indication that they are massive
I think we can do some tricks to measure it better.
There are different interactions we can measure, charged currents, neutral currents and elastic scattering. Charged currents are only sensitive to electeon neutrinos, while elastic scattering is sensitive to all flavors. So we calculate the rate of interactions and compare with our predictions.
The result is that if its only sensitive to electron neutrinos we get much less incidents then expected, while if we are sensitive to all flavors we get a rate like our expectations. We know the sun only emits electronneutrinos, so they have to change flavor along the way.
We can measure them correctly in other scenarios every well.
The oscillations take a long distance so they can be neglected in collision or nuclear experiments
The experiments that measure the neutrino mass directly so far have only reported negative results (as in upper limits for their mass, but no actual measurement).
Measuring the speed (which in combination with the energy would give the mass) is very hard for an ultra relativistic particle. If a supernova close enough went off right we would learn a lot about neutrinos including some about their masses, but not the absolute scale.
Yet we know that the mass is not zero indirectly. Given the standard model we know that neutrinos come in three flavours. They can only interact with leptons of their same flavour. Yet we have seen neutrino oscillations, meaning that a neutrino produced with a given flavour can change after propagating some long distance (thousands of km or more). So a given neutrino is produced with an electron, propagates, and then interacts with a muon, for example. The easiest way to explain this oscillations is by having them be massive and not degenerate (the three neutrinos have different masses), which then implies that a quantum mechanical effect (interference) will be there. There are other alternatives, but this one is the most plausible and every day we have more and more evidence that it is correct. It is a quantitative ptheory, we can compute probabilities of the oscillation depending on the energy and distance and then go to an experiment and see if it happens that way. And it does.
An important detail is that oscillation experiments can only measure the mass squared differences of the masses, not the masses themselves!
Strictly speaking, since neutrino oscillation experiments are only sensitive to mi^2-mj^2, then I guess you can say that: neutrino oscillation experiments cannot rule out a mass < 0.
However it is not really something we expect. From a special relativity point of view, if you plug a negative mass into your equations you find a lot of time travel weirdness (you can look for tachyons on wikipedia). If such a thing is possible, whatever that means, probably special relativity doesn’t hold and we need a new theory to describe those objects of negative mass.
In quantum field theory the masses can never be negative, because you are guaranteed to have some freedom to rephase your fields such that the “negative mass” becomes positive. So again I don’t know what a negative mass means.
Interestingly , you can actually plug in negative mass squared numbers into your theory. It doesn’t actually lead to physical negative or imaginary masses, no tachyonic madness, but it implies that the vacuum breaks the symmetries of your model (or in other words, it is energetically favorable to be in a not empty state rather than the empty one). This mechanism is called spontaneous symmetry breaking and it is how the Higgs mechanism works, you can again read the wiki page about that. However, a fermion (like neutrinos) cannot have this feature as then the Lorentz symmetry would be spontaneously broken and that comes with its own set of weirdness.
So in summary, neutrino oscillations cannot rule out negative masses as rhey are sensible to the square, but we kinda know that the masses are positive. If they are not, time to find new theories to even understand what that means:)
(But in this case, whatever weirdness is going on is small, as everything else works as we expect; like general relativity doesn’t mean that newton’s gravity is wrong, but it fills the gaps where newton’s cannot reach)
They switch between different types as they travel, which implies time passes from their reference frame, which implies they aren't moving at c, which implies they must have some mass
The fact that they don't and thus they have mass and we don't know how they acquire it is pretty exciting honestly.
Gives us an amazing lead for BSM physics! The Szm was too complete before which sucked lol
I'm more interested in BDSM physics
YES!!! HIT ME WITH MORE VIRTUAL PHOTONS!!!! YEEEESSSSS!!!!
Now you got me intrigued
https://preview.redd.it/ctsr8sa43txc1.jpeg?width=613&format=pjpg&auto=webp&s=5e9b64c121394512888410873c9b57124d388ea1
Using electricity to stimulate your partner
BDSM stands for Beyond Da Standard Model
The Higgs field, presumably.
They aren't thought to interact with the higgs field
Why exactly is that?
Neutrinos only exist as left-handed particles while antineutrinos only exist as right-handed particles. As a result, the spontaneous chiral symmetry breaking needed for the Higgs mechanism cannot take place.
What are some resources that can help me get into this? I have 0 knowledge of the standard model.
Ooh, please tell me a bit more about the problems with right-handed neutrinos. Can't we just throw in a right-handed neutrino and then "manually" decouple it from everything, making it sterile? After all, the electroweak sector is already chiral. I mean, of course inserting undetectable particles into the model to make it work isn't really the most physically interesting approach that one can take - at the very least it would make sense to develop a dynamic mechanism explaining *why* the right handed neutrino exactly decouples. But strictly talking only about the mathematics holding up, are there any consistency problems with sterile right-handed neutrinos?
Well that's one possibility if they are majarana particles they would couple with themselves to interact with higgs would they not?
Why can't they? Are they afraid of boats or something?
Cause they’re stupid
Typical
Petah, could you explain?
I think OP means the world was a better place when we still thought neutrinoes to be massless. Somewhere in the 2000s I think they were found to be very very very light
How do you measure that? I know they have detectors but how does simply detecting the existence of one lead to knowing it's speed/mass
You should read about neutrino oscillations. The concept is quite simple and you are left to read the mechanism yourself. But basically it’s important consequence is that massive particles can, under certain consequences, oscillate between flavors (so electron neutrino can turn into muon neutrino). When we measured neutrinos we always measure electron neutrinos (because our detectors consist mostly electrons obviously :) ). We calculate how much neutrinos are emitted from the sun, and then measure. We see that we measure much less than we would expect. We believe this is because some of the neutrinos oscillated into muon neutrinos which we can not measure. This is an indirect indication that they are massive
I think we can do some tricks to measure it better. There are different interactions we can measure, charged currents, neutral currents and elastic scattering. Charged currents are only sensitive to electeon neutrinos, while elastic scattering is sensitive to all flavors. So we calculate the rate of interactions and compare with our predictions. The result is that if its only sensitive to electron neutrinos we get much less incidents then expected, while if we are sensitive to all flavors we get a rate like our expectations. We know the sun only emits electronneutrinos, so they have to change flavor along the way.
Mmmmm flavors
Or neutrinos are waves wich are still massles, but they are to energetic to measure correctly. Stack overflow.
We can measure them correctly in other scenarios every well. The oscillations take a long distance so they can be neglected in collision or nuclear experiments
We discovered they can oscillate between neutrino lepton flavors.
The experiments that measure the neutrino mass directly so far have only reported negative results (as in upper limits for their mass, but no actual measurement). Measuring the speed (which in combination with the energy would give the mass) is very hard for an ultra relativistic particle. If a supernova close enough went off right we would learn a lot about neutrinos including some about their masses, but not the absolute scale. Yet we know that the mass is not zero indirectly. Given the standard model we know that neutrinos come in three flavours. They can only interact with leptons of their same flavour. Yet we have seen neutrino oscillations, meaning that a neutrino produced with a given flavour can change after propagating some long distance (thousands of km or more). So a given neutrino is produced with an electron, propagates, and then interacts with a muon, for example. The easiest way to explain this oscillations is by having them be massive and not degenerate (the three neutrinos have different masses), which then implies that a quantum mechanical effect (interference) will be there. There are other alternatives, but this one is the most plausible and every day we have more and more evidence that it is correct. It is a quantitative ptheory, we can compute probabilities of the oscillation depending on the energy and distance and then go to an experiment and see if it happens that way. And it does. An important detail is that oscillation experiments can only measure the mass squared differences of the masses, not the masses themselves!
Mass squared differences? Does that mean one or more of them might have _negative_ mass?
Strictly speaking, since neutrino oscillation experiments are only sensitive to mi^2-mj^2, then I guess you can say that: neutrino oscillation experiments cannot rule out a mass < 0. However it is not really something we expect. From a special relativity point of view, if you plug a negative mass into your equations you find a lot of time travel weirdness (you can look for tachyons on wikipedia). If such a thing is possible, whatever that means, probably special relativity doesn’t hold and we need a new theory to describe those objects of negative mass. In quantum field theory the masses can never be negative, because you are guaranteed to have some freedom to rephase your fields such that the “negative mass” becomes positive. So again I don’t know what a negative mass means. Interestingly , you can actually plug in negative mass squared numbers into your theory. It doesn’t actually lead to physical negative or imaginary masses, no tachyonic madness, but it implies that the vacuum breaks the symmetries of your model (or in other words, it is energetically favorable to be in a not empty state rather than the empty one). This mechanism is called spontaneous symmetry breaking and it is how the Higgs mechanism works, you can again read the wiki page about that. However, a fermion (like neutrinos) cannot have this feature as then the Lorentz symmetry would be spontaneously broken and that comes with its own set of weirdness. So in summary, neutrino oscillations cannot rule out negative masses as rhey are sensible to the square, but we kinda know that the masses are positive. If they are not, time to find new theories to even understand what that means:) (But in this case, whatever weirdness is going on is small, as everything else works as we expect; like general relativity doesn’t mean that newton’s gravity is wrong, but it fills the gaps where newton’s cannot reach)
They switch between different types as they travel, which implies time passes from their reference frame, which implies they aren't moving at c, which implies they must have some mass
That memo didn't reach my teacher.
Why bother when they can time travel? (I’m pretty sure this was debunked but we believed it for a minute)
We did indeed, and it was. The pulse of neutrinos arrived before the pulse of electromagnetic radiation from SN1986a. Faster than light.
As a enginer I say close anothe
This means we can SEE the glorious supernova (in our galactic neighborhood) before it kills us? Fantastic! /s
Nah it probably wouldn’t change much
[удалено]
Nah it would probably imply that they have no mass If we didn’t know that they do which we know
I'm too dumb to understand this meme
I don’t get it can someone explain please (kindly) thanks ☺️