The Future of Particle Physics
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MorningYearDayCERNLecture/Conference
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YearMusical developmentDose (biochemistry)Elementary particleLecture/ConferenceMeeting/Interview
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Bill of materialsRulerFeynman diagramParticleProzessleittechnikScoutingNeutronCrystal structureBosonAvro Canada CF-105 ArrowPositronScatteringElectronGreyHose couplingGeokoronaWeak interactionLunar nodeRelative articulationDayFACTS (newspaper)Radioactive decayFeynman diagramElementary particleCartridge (firearms)Cell (biology)Hot workingLamb shiftMagnetic momentNeutrinoRulerSpare partGreyContinuous trackProzessleittechnikMassShip classNeutronScatteringElectronNatürliche RadioaktivitätFullingKühlkörperRedshiftBrake shoeBird vocalizationStereoscopyMachineElectrodeKoerzitivfeldstärkeWeekForceLastGenerationSeries and parallel circuitsBoatHourCylinder headCableRail profileEnergy levelTissue paperYearStagecoachTrade windNeutrinoWill-o'-the-wispDyeingElectric power distributionSpeedometerHammockCorporal (liturgy)AlephOrder and disorder (physics)
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GreyHose couplingScatteringProzessleittechnikStud weldingElementary particleTurningHiggs bosonMassRRS DiscoveryMassRadioactive decayDayGentlemanLadungstrennungHose couplingCurrent densityTimerWeak interactionElementary particleHiggs bosonMachineTypesettingSunriseGround effect vehicleStrangenessGreyYearProzessleittechnikSeries and parallel circuitsThermostatHourBubble chamberFACTS (newspaper)LeadWeekTurningField strengthRailroad carBird vocalizationMeasuring cupCartridge (firearms)Direct currentSeeschiffOrbital periodStagecoachPaperBombComputer animation
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Elementary particlePlatingProzessleittechnikParticle physicsMaterialTypesettingBinary starYearDirect currentDrehmasseRRS DiscoveryRelative articulationDayDomäne <Kristallographie>Scale (map)Club (weapon)Angeregter ZustandSeparation processCartridge (firearms)Power (physics)DiffusionSeries and parallel circuitsReaction (physics)PaperOceanic climateWater vaporLecture/ConferenceMeeting/Interview
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Transcript: English(auto-generated)
00:13
Good morning everybody, welcome to this Agora talk by Professor Martinus Tini Feltman.
00:20
It's a pleasure to have you here. Twenty years ago you received your Nobel Prize and I think five days ago you had birthday. Happy birthday to him. So my name is Rolf Hoyer, I have been Director General of CERN for a few years
00:43
and I have the pleasure now to chair the talk. Tini, please. Thank you. I am sorry that the title of my talk, which I had to give before I made the talk, has no relation whatsoever to the content of the talk.
01:04
I often do it that way because there is nothing much you can do about it. So I will essentially try to give you a history of this field theory, what I will call field theory. The object that I am talking about is quantum field theory
01:24
and I will take some subject of it and I will tell you about the difficulties from it and I will give you a feeling, first of all, of what it is doing and I will also want, and that's very much my intention, to make you feel how difficult it is, real difficult.
01:43
And I can know that because I have been doing that for so many years and all the time there is a new twist, something. So field theory has been developing in a very slow manner. And if you look here, let's see where I am going to stand.
02:10
God damn it. Okay. So I will describe here the development of field theory, the theory describing the physics of elementary particles.
02:25
And the theory has had many difficulties, mainly of occurring, all the difficulties would occur in the theory that you try to make a real calculation but what you get as a result is infinite and nothing is much infinite in this world
02:41
so at that time you know something is wrong. That was the situation that, well, I've sort of had through all my life with field theory. You start off by saying everybody is infinite and then you work your way carefully around getting to the proper view and intention.
03:04
And that has been going on for a long time and just an idea as to how difficult it is, let it be an idea to let me give you an idea. You start with something, you have to wait many years before there is another move,
03:20
typically 15, 20 years and that gives you an idea of what kind of thing it is. So in the course of the year we have been capable of treating those infinities and knowing what to do them. And in the end, so as I say here, the importance of the theory is
03:43
that you can calculate processes and check if they agree with experiment and they are not going to agree with experiment if they are infinite. So that is the aim of the thing. And here we start, I want to start at where it really starts,
04:02
with Lorenz around the year 1900. And around the year 1900, Lorenz made really big advances in the theory, which I don't think everyone appreciates enough, but anyway he did. And in this particular case,
04:22
where it goes about the self-energy of the electron, there was another guy, Mr. Max Abraham, who as you can see did not get very old. And then there was Lorenz and these two people produced a model. The first time that it was needed,
04:41
the model for an electron was thinking of it as some kind of a sphere, in which this charge is distributed on the surface of the sphere. It is a very crude way and I'll tell you also why. And so now what happens is that when you want to make a point electron,
05:02
you let that sphere shrink. But the energy, when you want to shrink all this together, you have to apply more and more energy all the time. And by the time you get to the real two points, you have spent an infinite amount of energy.
05:21
So that's the first infinity and you have here a thing. You can always make an electron having a given charge. We call that a regulator mechanism. You make things finite. There's a parameter in search that you get to what you think is physics. So that is what people had to live with at that time.
05:44
And what was wrong with that approach is not a thing that was immediately realized but it came later on. Quantum mechanics had to come before that. You cannot describe processes evolving standard.
06:01
You cannot describe processes of discerning the equation and things like that. They cannot describe theories where you create particles. So you need something else and that's where you need quantum field theory. Quantum field theory has in it the mechanism of creating other particles.
06:22
Quantum field theory was created in 1929 by Heisenberg and Pauli. And the calculation of the electron cell of energy was done by Weisskopf in 1939. And you can see how the enormous time intervals before any move was done.
06:42
So here you have these three people, Heisenberg, Pauli and Weisskopf. And this was the state up till about 1940. And the result of all that manipulation, particularly one of Weisskopf,
07:04
is that the degree of diversions of the electron, as you were shrinking the size of the electron, it became logarithmic instead of linear. So that was an advantage. Still not much, but still. And now if you deal with infinite objects,
07:24
you must make a way of making them finite so that in the limit you go to what you think is physics. But in the meantime you sit in this artificial situation with a parameter in it that moves essentially to physics.
07:42
That's called a regulator mechanism. If something is too big to handle, you size it down and then you let it go. The regulator mechanism is one of the difficulties of this field theory. And the question, no complication arrives.
08:03
The regulator mechanism may violate important properties that you have seen to be valid. And one of them is called Lorentz invariance. It's the relation between parameters in one system and the other anyway.
08:21
That is violated. Lorentz transformations cannot be, have to do something with that regulator mechanism that is not all right. So it's fear to give you an idea. You have an electron and the regulator mechanism is that you let that sink. But now if you move, if you give the electron some speed,
08:44
it actually of course changes form. The pieces should become sort of an act if you know what I mean. And so you can see very quickly that the regulator mechanism changes if you move.
09:02
If you go from one system that doesn't move to a system that moves. And so you don't like that. Now Pauli and Villar understood this and they developed a rather complicated regulator mechanism that could deal with that situation. That Pauli-Villar mechanism stood for a long time,
09:23
but then it turned out it was also not adequate. So that shows you one of the difficulties that you have in a theory. A sphere doesn't stay a sphere when you move. Okay, Lorentz invariance is of course the relation between a system here
09:41
and one that goes with a certain speed with respect to that original system. Now then there was the great revolution of 1948. In 1948 there were two experiments that could not be understood with the theory up to that point.
10:03
There was the Lamb shift and the anomalous magnetic moment of the electron. These were quantities you could measure and no one knew how to calculate them. So here's the big thing. We get something, it's of course anything you want, and every physicist wants something that you cannot calculate
10:23
and yet you know it is there because it's finite. So that gives you some push to start working on that. And the question was how do I solve that? It was solved in a manner which is sort of funny.
10:40
Mr. Kramers from Leiden, who was a great physicist I must say, he died a bit too early but in any case, he had this idea of renormalization. A new idea and all it did really is notice the fact that you have an electron
11:00
and the mass of the electron, if you can imagine, here is physics, here is the electron and I've made a sphere. And then when I go to physics there is something, the experimental mass is going to be the sum of the two, the electron what it is like that
11:21
and then the electron that has to do is the cell of energy of the electron. That infinity that I was talking about in the beginning that you get when you push the thing together. Now Kramers argued that the great invention of Kramers which shows you that great inventions are not just necessarily complicated
11:44
but what Kramers said, hey, the experiment thing is the bare electron without its sphere or whatever plus the cell of energy of the electron. Well, he said, I don't know what bare is
12:01
and if cell of infinity, why should I not absorb it in the bare mass? So Kramers got the idea that if you have a free parameter in the theory, you can actually hide some infinity in there and you will not sense it. So you understand, here is the theory, somewhere has an infinity in it
12:24
and by the time you get to the answers that the infinity has cancelled away and you're left with a finite piece. That's what Kramers did and that was a breakthrough and so in 1948 that breakthrough did help people in computing these two quantities,
12:45
the one of the Lamb shift and the anomalous magnetic moment of the electron. So here we are now, we have arrived till about 1950 and all that theory has gone all the way from Lorenz in the old times
13:00
to this situation today, you're not even clear what you have done but in any case we now have a theory that at least works in certain cases and that works very well. Now, this has become something a part of field theory and in field theory there can be two kinds of field theory,
13:25
field theory where every infinity can be absorbed in a free parameter and theory, so you cannot do that. The first one you call renormalizable and the other you say is non-renormalizable, of course.
13:43
So after you have done this renormalization in a proper manner, you can start computing experimental quantities. Then there comes quantum electrodynamics and there was another advantage which perhaps took some time for people to understand how much of an advance it was.
14:06
It is Feynman who made a contribution in formulating and computing this theory and he did that by introducing diagrams like you see one over there and these diagrams would, you have a diagram, you look to a certain process,
14:25
you know what diagrams are going to correspond to it and then you can compute by certain rules, Feynman rules, you can actually do a computation. It was a very beautiful and simple way of keeping track of all the complications of field theory.
14:45
So given such a diagram, you can compute what it does and that allows the theory to produce experimentally observable results. Now quantum electrodynamics, that is what this produces.
15:04
I tell it to you here extremely briefly but it is quite a big subject. Quantum electrodynamics through the Feynman rules became a very easily manageable theory and that was a god gift because if you look to the authors of those days
15:24
that were doing things not using Feynman rules, you had a hard time just understanding vaguely what they were doing. Well anyway, there comes the next complication. You see, I'm still busy talking field theory.
15:43
The next complication is that apart from quantum electrodynamics, electrons, scattering of a position, things like that, there are other interactions that we would like to describe also and one of those interactions is the weak interactions as we used to call it.
16:05
There was a class of interaction. No one knew anything about them but the only thing in common was they were weak, much smaller than the electromagnetic ones. So if you had the competition between these two forces,
16:23
you know that you would never see the weak one because the other one was so much bigger. Well, one of the processes that belongs to that class is the decay of protons. You see the neutron, the other neutron. You see the neutron can decay and it does in three particles,
16:44
a neutrino, electron and a proton. And I have to tell you that people had been studying that, of course, for a very long time, not in the least by Fermi and this particular process suggested something.
17:02
You started to write down exactly what's possible and what's not possible. The way that goes is you write down something that contains a lot of free parameters and you fix those parameters by looking to experiment and then something comes out in the end which you believe is more or less corresponding to the experiment.
17:24
So that's what happened there and what you discovered is that this process and others very analogous to that, they suggest that you couldn't see it. I mean that's really the horror.
17:40
You go through all this business and now you have to deal with particles you cannot see. The particles you cannot see, there is one. We think, we thought in those days. I remember those days very well. I got in the business more or less at this point. So you knew there was a W. You think, you thought, and then you ask yourself what is the mass of that particle.
18:06
Well, you didn't really know. And all in all, it's full of mysteries if you wish. But in any case, you started thinking in those days and I came rather early quite convinced of that.
18:21
You got to thinking of the fact that there was an intermediate particle. So somewhere in this thing, there's a particle and it has a functional outer heart. You see it in the second diagram. There you see how we were thinking that this new particle was functioning.
18:42
You had the node neutral. It would decay in a proton and that new particle. And given that it is quantum mechanics, you really don't know how heavy that will be. And then that new particle decays in a neutrino, anti-neutrino in this case, and an electron. So in that way, you could understand that process
19:02
and you could add one thing. Look, if you know it that way, you cannot fix the mass of that new particle. But you couldn't. It was, it could be something. You could adjust the parameters to accommodate any mass. So at that time, which was around, let's say, 1963,
19:24
we had, the physicists had themselves faced the following question, what is the mass of the vector motion? And this was just very difficult. And why it was so difficult? Well, we found it out quickly enough.
19:43
It turned out that that particle was exceedingly heavy of the order of magnitude of 80 times, 80 times the mass of the proton. So there is a virtual particle, meaning it exists only a fraction of a second, and it is so heavy, 80 times heavier.
20:04
Well, it gets very hard to produce. Our machines were not big enough. Experimentalists didn't know how to handle it. And so all together at that time, we were poking around. I remember experimentalists getting to introductions
20:21
where the vector pose of mass was, the one that they would measure would hang around 3 GeV. It was way off of what it could be. So there was a very long time that we have, a very long time, less than 10 years, that we have lived with this W, with this W particle,
20:42
of which we didn't know the mass. Now, the next thing you can do, if you look, the next thing what you can ask is, hey, if there's one W, why shouldn't there be other ones? Or the W that were coming from the neutral decay
21:02
were having an electric charge. So could there be neutral ones? So the search for neutral currents of that type started on and became very important in physics for some time. And there was, it was about at this point
21:22
that you had to start making a theory. And the theory was awfully complicated. I cannot say differently, but really, when you started on it, after a day or so, you got overwhelmed.
21:41
Certainly happened to me. And so you started off by this interaction. Totally hypothetical, but you just assume there exists the simplest possible interaction between Ws, and there is a W here. These are the assumptions you made.
22:04
And now here, the theory, you start doing all kinds of things, and then there's new infinities arise, and the question is, if there are infinities, will the theory be renormalizable?
22:21
Are we capable of handling the theory? And I can tell you this, when you start off by that theory, with this interaction only, what you get is a totally unmanageable theory. And it gets very complicated later on. So you start to introduce, what happens is,
22:40
the smart guy doesn't give up. He takes that interaction, he computes if there are any bad infinities, ones that he cannot absorb in some parameter. And he takes that theory, he looks at the bad infinities, if he can make them go away by adding on other interactions.
23:01
So one starts to complicate theory, adding more interactions between the participants in that theory, in the hope that you get less and less infinities. And in this case, bad infinities indeed did appear, and you had to introduce extra interactions
23:21
if you wanted to get a theory that would make any sense. And the only guide that we so far use in building the theory is renormalizability. The only thing we want is that with the interactions that we have been introducing,
23:41
all the answers, all the infinities, can be absorbed in the given parameters. In short, you tried to add interactions in such a way that the theory is renormalizable. Now those infinities occur, and you have to introduce a four-point interaction,
24:01
nicely enough, very elementary there, very simple. You have to introduce that interaction, and it makes so many infinities go away. In fact, most of them go away. And of course, that interaction in itself gives rise to yet other processes.
24:22
So you solve one complication by adding another complication, and that means you have to start from zero to see if you are still getting somewhere. Well, the next thing you do is you make new diagrams, and you choose the strengths,
24:41
the coupling concepts of that new interaction in such a way that all the bad interactions cancel. That's the way it's made. Am I exceeding some timer or something or other? Yeah, the second order. It's not that I intend to stop.
25:00
No, no, just continue. Okay. In this way, you can, in that theory, get off almost all of the bad infinities, and the resulting theory has several new, very well-defined interactions. It exists already for strange reasons,
25:22
and it's called the Yang-Mills theory. Now, one stubborn infinity remains. So we were doing that theory, and after canceling, really, a large number of infinities, there was one who just insisted on being there
25:42
and couldn't get rid of it. That infinity, very stubborn, occurred, among others, when you scattered two Ws, a totally hypothetical process, but on paper, at least, you could figure out what's happening there, and it turns out you could cancel that infinity, too,
26:03
by introducing yet one more particle, and that particle was already introduced somewhere in a theory. It's called the Higgs particle, after a man now called Higgs, who is an admiral, and that's a diagram of a type that you had to add
26:21
that would come because of the Higgs particle, it's the dotted line, and that particle solved all the problems, and we got a new theory for the weak interactions that was renormalizable and that you could calculate everything from,
26:41
and then you could start calculating and doing experiments, and I can assure you that it was a great day when we found out that we could, in this way, indeed, and it was the truth, this was the way the world was made. It was not just a fantasy in our heads, it was there,
27:00
and those experimental verification were there in that period. They took a while because all of that is not that easy, but the new theory, can you see how we get there, there it is, and we get that,
27:21
coming after Lorenz, we get that whole buildup of a theory, and there you stand, and in the end it turns out the truth, which is really very nice. Now this new parameter, this Higgs particle, the renormalizability of the theory,
27:40
this strange concept of being able to cancel all infinities, can you imagine, theoretically, what a funny concept this is, that that leads to physics, and the physics is the existence of the Higgs particle. At that time you didn't have to specify the mass of the Higgs,
28:01
so that made things a little bit easier, but anyway, here are these two people, I consider like the key people of that history I'm talking about, Mr. Peter Higgs, who was sitting in Chapel Hill in 1965, and who, I might say, didn't really know what was going on,
28:22
and then there's Mr. Kramas, who died too early, and that, in a sense, was the end of everything, and if you wish, you can now ask questions, I'll try to answer that.
28:42
Thank you very much for this very nice talk, this very nice overview. Questions? People who want to ask questions, please go to the microphone so that he can really hear it. Please. And take into account that I'm deaf. Okay. Is this loud enough?
29:01
How do we do that, by the way? Okay, first of all, thank you very much for this nice overview, my name is Mortier, and I wanted to ask, given the original title of your talk, I still want to ask your opinion on the future of particle physics, so you as a theorist, what do you see as the future,
29:21
where should we look for new physics, and if it's allowed, I would also like us to ask a similar question to Mr. Heuer, but in terms of the, it's not allowed, okay, then I focus on this. So you want to know the future of elementary particle physics? Yes, where should we look? There isn't really any.
29:40
What did you say? No, I couldn't hear it, sorry. You got out in time, you see, he was the director of CERN, up until today, more or less, well, not quite, and so he left, so at a time that he didn't know anymore what to do. The question is, can you predict where you go?
30:00
In that sense, you can ask a future of particle physics would imply that there is something in the theory that tells me where to go, but I have to say to my horror, I just have not the foggiest, and I don't think most people do not, but I have no idea where we would have to go to,
30:20
for all I care, and that's the real difference with the present state of affairs. If you take the theory as we have it today, and we move up to ten energy scales, it's still a perfect theory. So there is nothing that you have to repair or change or whatever to improve it,
30:42
and for this reason, you don't know what the answer is to your question, you just don't know. But then, don't forget, that's the way it goes in physics all the time. When you do experiments such as Mr. Röntgen, in those older days, he was doing experiments,
31:01
and do you think he was busy trying to fight the Röntgen race? Of course not. No one would do the existence of those things, and he got them by accident. He had a plate of some material hanging somewhere, and the thing changed when he was directing in that direction.
31:23
So that's normally the nature of physics, and that's equally normally the question of the practice of physics, or the experiments of physics. You go in a direction, in a domain, which you don't know, and you try to clear it up,
31:41
and then you may or may not in the process make an interesting discovery. It's always interesting, but I hope I made myself clear. I'm not saying that you should go in some other direction, because they also don't know what they're doing. I think you made it perfectly clear.
32:01
I mean, if you would know the future, it would be too easy, and I tell you my opinion privately, but not here. Okay, then I'll talk to you later. Thank you. Come on. Any more questions? Come on. And we want only questions that are easy to answer. There's one. Easy to answer.
32:21
Okay, let's try. So could you give us some insights maybe where the problems are in finding quantum gravity, because we have seen how you go from electrodynamics to quantum field theories, but people have a very... Insight into quantum gravity, was it? Yes.
32:41
We didn't make much progress, and just to be sure, it's not that I don't believe in it, because both my companion of the time, Mr. Toft, and me, I think we made one of the very first real advances in the quantum, quantum of gravity. But then very quickly,
33:00
you run into another problem, and all I can say is we don't understand it today, and maybe we'll understand it tomorrow, or maybe this must be left to our grandchildren or something like that. But there's a piece that no one knows how it goes. Gravity towards quantum gravity
33:20
is one big question mark. What can I say? Okay, it was an easy-to-answer question. It's not that easy, no. I agree. The lady. Hi. I would like to know a little bit your opinion about just relating
33:41
to this first question. The standard model theory is great. It predicts a lot of things, but we do have some things that are not perfect. That's why we have some BSM theories. So is there one in particular that you like more, or I don't know what do you think about them? Is there any type of BSM theory
34:02
which you like more than the other? The question is what makes me like a theory? And the answer is sort of trivial. It has to work. For example, many theories, it looks like they could work, but then we don't see them experimentally.
34:21
We don't find anything. So I don't know what's your advice for us. I mean, I think we're in a moment that it's a bit hard to keep going, right? Like after so many years where particles kept popping up everywhere. Now it looks like we have many theories that might be good in paper, but then experimentally we just keep excluding. So I don't know,
34:41
just your opinion or some advice for us young scientists. What's she like here? Well, I think she wants to know what you advise or what you should do. You see,
35:01
I can only tell you this. If you make the right choice, you will eventually sit here. I like this advice.
35:23
No, you can talk. So I have a question related to the issue of quantum gravity. So in particular it is true that it was shown starting from the Einstein-Albert action
35:41
that there are divergences at one loop level and that this was shown... Short, please. Short. Okay. Okay. There are divergences starting from the Einstein-Albert action, but when adding a more additional scalar degrees of freedom,
36:01
namely by considering the stellar action, it was shown that this is renormalizable. And this seems similar to what has been seen in the case of... So what is the question? So the addition of scalar degrees of freedom seems to cure the problems of...
36:26
Don't go away. If I understood correctly, she wants to know if the addition of a scalar particle or a scalar field
36:40
solves essentially everywhere the divergences. In the case of gravity for example. Adding a particle in the case of gravity? I still don't get it.
37:01
Me neither.
37:21
Yeah, that is what I said. I thought. Yeah. Does this solve the divergences? Adding a scalar particle into the field, into the theory. Okay, I think
37:42
we skipped that question. I'm sorry. That's too complicated for an experimentalist like me. Due to malcommunication we are not getting anywhere. We introduce another question. Hello. Both having been directors at CERN, do you have some sort of funny stories
38:02
from organizing such interesting characters I think? It's a question to me. Either one of you. This is not my event. I'm just moderating. And just tell them that there is nothing funny about being director of CERN. Thank you.
38:20
That's a correct answer, yes. Give first the floor to the lady and then it's you. Okay, I have a shorter question. As you say we have this standard model that works very well with the Higgs, but we have some particles like the neutrinos that don't seem to
38:41
interact with the Higgs. Do you think we will have some insights this way? We have the standard model and the particles are interacting with the Higgs, but there is something else like the neutrinos which don't seem to interact with the Higgs. Could that be a hint where we have to go?
39:01
I'm not saying that you cannot find variations about the standard model that are possibly another theory. And we are not trying to find theories that would fit everything and yet are different theories. Actually what you will find is very limited. I think there is not too many possibilities.
39:22
But why would you? I think most of us are quite happy if we have some theory to some situation and later on we may start to investigate what is still the best evidence, the only possible and so on. So certainly those things,
39:41
those questions may be asked, but not immediately, I would say. I hope I answered your question. I have this feeling that I am not answering anything. Well maybe nobody can right now. I think these questions concern really the future and they are difficult
40:01
to answer in any case. Yeah, that's of course the other thing. You are in this business like I have been for so many years and then you have the worries that you had. I remember at CERN John Bell and I were good friends in those days. We started walking
40:20
the corridors of CERN wondering if we would ever get to interactions for the W, finding it, if it were let's say a hundred GEV. And we both started to laugh because that sounded so much like a totally absurd energy in 1963.
40:42
But did we know that we got later on storage rings, colliding rings and at last the energy went up way beyond what we were thinking. I think we were naive to the extreme. So what you speculate today,
41:03
tomorrow you speculate something else because you have gotten a new insight. In that way it may help to speculate on something so that you know the limits of the possible. Thank you. I keep hope then. In any case.
41:21
I'm curious, what experimental results are you guys most looking forward to over the next 10 or 20 years? What are the experiments that you guys are most excited to see turn on? Which experiments are you most excited about for the next 10 years?
41:40
Where would you like to see? What are you doing, I think he has to do something with neutrinos if I'm not mistaken. I don't know what is exciting can only be discovered if you wait a bit and see what comes out
42:01
and that's the way it is and that's the way it will always be. You do research and an essential part of it is that you are busy doing something or you don't know what it is and what for. So what do you want?
42:20
But if you want to know that you can always go look in another field and you see what people are busy with. I've been looking at people who are busy looking to soap bells. I thought that for my life of it I had no idea what was interesting about soap bells and indeed
42:40
there was nothing. Okay, so your conclusion is stay in particle physics, okay? I'm from China and recently many particle physicists suggested China to build a larger accelerator.
43:04
So there are some debates. Someone thinks yes China should do but some other people especially turning young think China should not build such an accelerator. So what is your opinion?
43:22
What is your opinion about the next large accelerator? Which by it? Well, there's a number of things you should take into account. First there are only a few parts that you can actually use to be accelerated. Protons, electrons, you're already halfway.
43:42
You can use muons. It gets more difficult. So anyway, so that limits your number of machines that you can make. Then you can make colliders or circular colliders and so on and then again what I've seen in my life is that usually in any one given situation
44:02
there's essentially only one choice. And then that's the way it goes. The reason is that your choices are limited. There's only so much you can do with the existing operators and capabilities as well as the money. So in that case
44:21
making the question of what would be the best accelerator to make it just sort of makes me laugh. We never had that choice. So if I meant my understanding
44:40
of your overview is correct you basically propose the neutral vector boson before any hints of this particle. So how would the situation different from our current situation of standard model?
45:00
She said if she understands correctly your recipe was to introduce a scalar particle. A vector, neutral vector. A vector? Yes. Yes, sure. A neutral vector. Yes. And what is different to this situation today? Yes, so there's
45:20
no hint of this particle but you still proposed that one and that will lead to a great achievement of a standard model. I don't understand. The question is you have a scaled particle and then you discover a way of how things work and that consequences you start
45:40
shearing and you say it works. And then someone says shouldn't you try something else and see if it works and say you can do it. But in all frankly I think the particle that we had a scalar particle X particle
46:01
I think it's exceedingly difficult to find an alternative. So it's I don't know how we cannot answer your question. You should come with the answer. Can I readdress my question? So I mean the neutral vector boson.
46:23
Okay, I can answer later. I think we have to wrap up now because I think the time is over if I'm not mistaken. So first of all thank you very much for the lecture and secondly for answering the unanswerable questions on the future.
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