This is what it is: it is a neutrino oscillation, an interconversion.
This is what it is: it is a neutrino oscillation, an interconversion.
That is, touch the Standard Model, well, just like Newton’s law, right? There, Newton’s first-second law – they are, of course, wrong. Everyone knows that they are wrong, and the correct laws are the laws of the theory of special relativity. Therefore, there, what you are taught in school, "Newton’s laws" – they are wrong. But we must understand that they are correct – they work – in the area of ??their applicability, when the speeds, for example, of particles or, there, bodies are much less than the speed of light. Then everything is fine, Newton’s laws work, and the expansion of Newtonian mechanics must have happened in such a way (and it happened) that in the correct limit, the limit when the speeds are small compared to the speed of light, Newtonian mechanics is restored. The same is true here: in the limit of energies of comparatively low ones, those to which we have reached, the Standard Model must be restored from any theory. And already inside the Standard Model itself, you can see that you can’t do anything with the masses unless you introduce something like the Higgs mechanism.
Question. Excuse me, please. If we don’t find Higgs at all, can we say that he just might be heavier?
V. A. Rubakov. Who can be heavier? Higgs? No, it should be relatively light, it should be within reach. This is the whole, as they say, the intrigue that the Higgs cannot be made heavier, its mass should be comparable to the mass of those particles that we know, which received mass due to the Higgs mechanism. That is, 172 GeV are the heaviest particles, well, the Higgs can have 300 GeV, well, 400 GeV. But not much more.
Question. But if we compare with leptons – carriers, the same W, are many times heavier. Why can’t it be many times harder here?
V. A. Rubakov. Can not be. This is theoretically impossible, this, as they say, contradicts … So, so. There are iron, as they say, theoretical arguments that say that it cannot be heavier than 800 GeV, this, as they say, is absolutely iron argument on this topic. Less iron – 400, and, so to speak, not at all iron – 200.
Question. Are there any hypotheses explaining symmetry breaking and not using the Higgs boson?
V. A. Rubakov. There is. But … There are, of course; so to speak, scientists are a people … theorists are an inventive people, they do not stop at a single possible explanation, they are looking for alternatives. But this means that all of them, in one way or another, lead to the existence of new particles similar – not literally identical in their properties, but similar to the Higgs boson. They are sometimes similar in a rather broad sense, but still these are particles with masses lower than TeV, and still these are particles whose properties are quite close to those of the Higgs boson. So the Higgs boson itself will not necessarily be discovered in such a simple version, but something analogous must necessarily exist in nature.
Okay, let’s go further.
So, well, it is important for me that you imagine what the scales are in nature, in fundamental physics, which now seem to be fundamental. The scales of lengths and, accordingly, energies.
Question. Can i ask you?
V. A. Rubakov. Yes. I can’t see where.
Question. Here is the field causing symmetry breaking. But as far as I know, it’s kind of scalar.
V. A. Rubakov. Exactly. It’s not rotational symmetry or anything.
Okay. But for something interesting, it must probably be anisotropic?
V. A. Rubakov. Not. No no no. Anisotropic – if you and I would live then in an anisotropic world, in a world where it would be …
Question. (inaudible) If it’s not anisotropic, then how is it …
V. A. Rubakov. No, it breaks the so-called internal symmetries. These are not the symmetries that we know, that you know (these are the symmetries, there, in relation to space shifts, time shifts or rotations in space). There is the so-called internal symmetry – symmetry, which has nothing to do with the symmetries of space. In particle physics, there are a lot of such symmetries, and in particular, here, the masslessness of a photon is a manifestation of one of these symmetries. And here is the Higgs field – it is not scalar with respect to internal symmetries, as you said. It knows, feels and transforms with these internal symmetries. Just as the vector rotates during the transformation of rotations, so the Higgs field rotates, but not in our space, but, as it were, in the inner space. And it breaks this internal symmetry.
Okay, so the scale. There is a fundamental scale that refers to strong interactions: it is about 10-13 cm, the size of a proton or the scale of nuclear forces, if you like, and the corresponding energy is about GeV. The second scale is the scale of electroweak interactions. Electromagnetic weak interactions actually represent some kind of unified interaction, but it is precisely due to this very violation of symmetry that we do not really see this. Weak interactions are responsible for phenomena such as beta decay, for such rare and rare phenomena – that’s why they are weak interactions.
So, their scale is larger in energy, and this is precisely why the weakness of the interaction is connected: the larger the scale of energy, the weaker the interaction. This is, as they say, the situation. Their size … size is smaller. The typical size for them is just 10–16 cm, the very size above which the LHC is trying to break through, will be able to break through, and this is where the interest lies.
And finally, there is the scale of gravitational interactions. You can’t discount gravity as well. This is a very weak force. Well, so to speak, on Earth it seems that it is strong, but this is due to the fact that the Earth is large. If you look at the interaction of protons with each other, then the electrical forces between them – Coulomb interactions – are many, many orders of magnitude stronger than gravitational ones. Gravitational forces are weak.
And this is also associated with its own scale, an insanely small scale of lengths. Never in its life will humanity reach it on accelerators. 10–33 cm is an insanely small value. And, accordingly, the energies are gigantic – 1019 GeV. This is crazy energy, never in life will an accelerator be built for such energies.
Question. (inaudible) And if the accelerator does not work, then maybe you get (inaudible) cosmic particles (inaudible)?
V. A. Rubakov. No, cosmic rays don’t help either. This means that we are talking about the energy in the center of mass system. In the center-of-mass system, cosmic rays have many orders of magnitude lower energy. Nothing will help. We will never break into this area. This is just maybe with the help of cosmological data. And then, the chapter 24 of a tree grows in brooklyn summary question is big.
But, nevertheless, there is such a huge difference in the scale of fundamental interactions. I want you to understand this. And this is one of the very strange phenomena in nature that exist. Well, my point is that the Standard Model that I was talking about is experimentally tested – really well tested. Electrodynamics verified, accuracy level 10–8–10–12. Better than one billion. One trillion in places. And this must be taken into account: when you are trying to come up with a new theory, you must not forget that the old one has been verified with high accuracy. We know about the electroweak sector, about electromagnetic weak interactions with somewhat worse accuracy, if we talk about energies of the order of a hundred GeV. There, the accuracy is 0.1% – also excellent accuracy, I must say. You yourself understand that such accuracy – 0.1% – at the level of the world of elementary particles is a serious matter.
Why is this accuracy important? I’ll tell you what: electrodynamics has been tested with such high accuracy, and this allows you to test quantum theory. Quantum theory is not a trivial thing. It has, in addition to, so to speak, simple effects, there are so-called "radiation corrections". This is what it is. This means that in a vacuum, in addition to this hypothetical Higgs field, all particles are necessarily present, for example, electrons and positrons. They are formed and destroyed. Again, according to the principle of uncertainty, you can create a couple of particles for a short time – an electron with a positron – and then they annihilate back. It happens all the time in a vacuum. Quark with antiquark also appear-annihilate. This is all the time the processes that go on in a vacuum, and the presence of such processes – it leads … these are processes invisible to the eye, but it leads to an influence, to the fact that the vacuum – its such structure – affects the observable values. For example, at the level of energy in the hydrogen atom. This precision, in particular, is achieved by measuring – precise measurements – of the energy level in the hydrogen atom. They know about the electron-positron pairs that are created and destroyed in a vacuum (basically, electron-positron pairs are deposited). But not only: quarks also invest, less, but they invest. Therefore, when it comes to accuracy like 0.001, this means that the experiment is sensitive to these radiation effects – as they say, radiation corrections – to effects that are essentially quantum and the effects that occur in this vacuum.
On this basis, even before the real part … the top quark (for example), the t quark, was discovered, its mass was predicted. How? Quarks are also born and destroyed in this vacuum, and they affect the properties of other particles, such as W and Z bosons. And the measurement – the exact measurement – of the properties of the known particles led to the prediction of the mass of this t-quark, and the prediction was like this: 170-180 GeV. Really – 172. So theorists – they also eat their bread for a reason, they know how to predict – on the basis of quantum theory – to predict different things. In particular, such a prediction was made. Yes?
Question. Sorry, I heard that they want to prove the big bang theory with the help of the collider?
V. A. Rubakov. Well, let’s leave such questions at the end – of a general nature. Let’s ask questions …
Question. Can I have another question? In general, how do they arise, quarks? Well, in general, particles: you say they arise, are obtained from nothing?
V. A. Rubakov. In a vacuum? Yes, it is not forbidden, it is not forbidden for a pair of particles to appear for a short time, and everything that is not forbidden – everything happens. And there are no reasons. It is not forbidden – it means that it happens. That’s all the reasons.
Question. And if the Higgs boson is not found, does it make sense and can humanity now build a more powerful accelerator?
V. A. Rubakov. If the Higgs boson is not found, then I am afraid that it will be very difficult for humanity to explain why a new accelerator is needed. Because, so to speak, if you have nothing but the known particles, then it will be extremely difficult to explain why you need more energy, where again nothing will be found. Well, there is a chance that nothing will be discovered … It will, of course, be very difficult to explain, so to speak, to people, and to physicists in the first place – to themselves, because the expectation is connected precisely with this area of ??energy, which will be studied using the Large Hadron Collider.
Okay. So, despite the fact that …
Question. Please forgive me this question. If in a vacuum a pair of particles appears as if out of nothing for a short time, does it mean that conservation laws are violated for a short time?
V. A. Rubakov. For a short time, yes. And this is connected exactly with that uncertainty relation, it works for momentum and coordinates, as I wrote there, and there is also a certainty relation for energy and time. It should be of the order of this very Planck constant. For a short time you can have energy that is different from the average energy of the usual, so for a short time – yes, some energy may appear.
Even though the Standard Model is so well tested, there are some very serious considerations that suggest that the Standard Model is actually incomplete. That there must be a completely new physics, not the one that was shown on this transparency, on this little screen, where the composition of the particles of the Standard Model was shown. There must be new physics, new particles.
So, in fact, we know that the Standard Model is incomplete. This is a little distracting from the conversation, but this is the largest discovery in recent years in particle physics. So I decided to mention it. It doesn’t seem to have any direct relation to what will happen at the LHC, but nevertheless, it is really the biggest discovery, and I’ll talk about it. This is a discovery that leads to the notion that yes, the Standard Model needs to be extended, that this is not the whole truth.
This is what it is: it is a neutrino oscillation, an interconversion. So, for example, the Sun … You remember that there are three different types of neutrinos: there are three leptons – an electron, a muon and a tau lepton – and, accordingly, three neutrinos – an electron, a muon and a tau neutrino. Three different types. So, in the Sun, in thermonuclear reactions, an electron neutrino is formed. And they arrive on Earth as neutrinos of other types: muonic and tau. Neutrinos turn into each other. Or in the atmosphere, due to the interaction of cosmic rays with the atmosphere, muonic neutrinos are born. And they arrive at the detector … Neutrinos interact very weakly, they fly through the entire Earth without interacting, and occasionally they are nevertheless detected in detectors. This means that they arrive at the detector as tau neutrinos – there is also a transformation. This means that neutrinos are, in fact, a lot of experiments, large collaborations, collaboration of different scientists from different countries. This means that it is confirmed: it is confirmed by ground-based experiments, accelerator and reactor experiments, where neutrinos are also born, neutrinos are also born in a nuclear reactor. And the fact that such mutual transformations of neutrinos of one type into others actually occur is an experimentally established fact today. This was done quite recently – well, recently by the standards of particle physics, on the order of, let’s say, 10 years, how to count. Well, the scale is. And such a phenomenon cannot be described within the Standard Model. The Standard Model, even with the Higgs mechanism, forbids neutrinos from having mass. So there is disorder in the Standard Model, and this disorder, in particular, is due to the fact that for some reason neutrinos turn into each other, although the Standard Model forbids them to do this. Well, here I have included some conservation laws that prohibit doing this, to the Standard Model, well, it doesn’t matter.
So now another piece of evidence of the incompleteness of the Standard Model has come from cosmology: dark matter. This means that in cosmology it is required, without this to go, it is impossible to go anywhere, it is required that new particles exist: stable, massive and electrically neutral. There are no such in the Standard Model. Stable, massive (heavy) and electrically neutral.
How is this known? It is known for a variety of reasons. Well, if you sum up all these considerations, it turns out that the picture of what the energy in our Universe consists of – it turned out to be very strange.