As the LHC has been Working and running people are beginning to ask the question: What comes next in the world of high-energy physics? Should there be another Collider? And it's kind of become an issue for some people because, The Large Hadron Collider, although it's doing fantastic science, It's measuring quantities to amazingly high precision, if you think of it in terms of the discovery of new particles, It's discovered one, which was the Higgs back in 2012. BRADY: Which is what it was built for! PROF: Exactly. PETER HIGGS: Really an incredible thing that it happened in my lifetime. PROF: But it's not found anything else. It's not found any evidence of dark matter, which throws through the world of supersymmetry. It's not found any evidence of more exotic things. Perhaps like extra dimensions or other new particles. It has demonstrated that we have effectively an interaction between the Higgs and the fermions, a force acting there that we need to understand better, because we can now probe that regime which we couldn't before. But the question is, Do we build an even bigger Collider? And it was brought to a forefront by the recent publication suggesting that there might be what they call a future circular Collider based at CERN. That's where the current Large Hadron Collider is. The Large Hadron Collider is underground in a ring that's about 25 kilometers long. The Future Circular Collider would be a ring that's a hundred kilometers long, four times the length. It would cost of order 10 to 20 billion pounds. Naturally a question that we need to ask ourselves, both as physicists but also society, Where do you want to invest these large amounts of money? There was a particular article that, at least within the particle physics community, was read a lot, by Sabine Hossenfelder, in which she said, Although she accepted that probing fundamental physics through a particle accelerator is the best microscope there is to do that, the fact that we've only made this one Discovery and we don't have any great ideas as to what is coming next in terms of theory Perhaps we should be deferring building maybe not even building a future Collider until we have our theories firmly better established and Then we can perhaps go ahead once we've said well this is almost certainly to be be the way forward and that and therefore that will dictate the form of any large Collider. BRADY: Rather than kind of fumbling in the dark PROF: I think that's a probably she would agree without that that the way that we if we Go ahead right now. We are will be basing it on physics that we already know but more speculative physics about what's coming next And so and it's a really important question to address for me personally I think it's it's a it's there's not a clear-cut answer I Remember back in the 1980s when the Large Hadron Collider was being put forward and maybe even slightly earlier People did think they knew what the solution was. They did think that Dark matter would be found in what was known as WIMPs, weakly interacting massive particles. There was we talked about a wimp miracle and There were natural candidates for this WIMPs, which were coming from supersymmetry The Higgs mechanism had been suggested back in the 60s and so there was a there was in some sense a well-defined path to go along and if I were in it But the very first conference I ever went to in 1983 was at the Royal Society and Stephen Hawking gave a talk there in which he said we Will know everything by the end of the century and it's all "N=8 super-gravity". He called it It was called and turned out not to be the case there was an example where we did think we knew where we were going and we the decision on the LHC was made and you do need to make these many years in advance, you know the LHC came into operation in 2008 Right, 20 odd years nearly thirty years after the initial proposal the proposal for the future circular Collider would have it starting in 2050 because you've got to build these things you've got to develop the technology Ed, are you saying that the large hadron collider didn't end up Discovering the thing it was built to discover? No it did. You're quite right You said at the very beginning its primary goal was to discover the Higgs, but it had secondary goals and there was a real feeling that it would probably be able to if it found the Higgs it would probably find the these WIMP particles because there was supersymmetric models which suggested that WIMP particles would be in the same sort of mass range as the Higgs. That wasn't the case And that wasn't the case they have just not they're just not showing up. In fact, no new particles of showing up. So the Argument for building the big circular Collider isn't there as strongly as it was for the LHC? In the sense of having a whole series of particles that you think you're going to find Yeah, as far as I can tell there's not, and in fact It would be a case that we'd be building it partly in order to actually use the upgraded LHC and of course the LHC itself still has many years left of its lifetime to go and Be using it Not only as a discovery machine to actually find new things that might might be there but also to as a high precision Machine to help us understand the standard model and in particular the Higgs and the interaction the Higgs has with fermions with the Things that you and I are made of the quarks and the leptons so to help us understand those interactions much much better because another way of finding new physics is to say here's my standard model prediction for some very exotic process then I go and measure that exotic process and I find a difference and the difference may only be in like the tenth decimal place but if you are Sure about the calculations that have gone into it and sure about the measurements then there's your probing your finding evidence of new physics This is the detector and that's one reason why you would go for it You know a much more powerful machine that can probe into these new areas Smaller length scales higher energy where things might pop up. We just don't know. It's one of the Frustrating things about this. There's two things that can go on here You can build a new Collider to find a new particle and have some paradigm change Yeah Or you can build one to just like fine tuning and get a higher resolution and better pictures and then two different arguments It feels like yeah, but in fine-tuning you looking for differences, right? It's not a case of I mean, yes, that's what you're always probing for you with a wave physics works Right as we basically we don't try to confirm models. We try to rule them out That's kind of in our heads we try to find deviations and that's what would this fine-tuning. It would be rather than having, you know Something smash you in the face. And so here I am, this brand new particle. Look at me. I've revolutionised things straight away It's a much more subtle way of doing it. You're finding deviations from what the standard model would say and and and Nature is can be like this it can it can hide These new ingredients that make it very difficult to find and if we don't build something, we're not going to find them this way Ed, I know it takes a lot of time to build these things, but still, wouldn't it make more sense to wait for the next really paradigm I think Sabine's got a very valid point here, but you know But but the question also is at what stage? In that process do you say AHA now it's time to build my new You know future circular collider Because there is kind of two two aspects to it one. Is that the technology involved in the under theorist? What do I know but I believe the technology involved in this is really complicated. Okay, you you they're always at the cutting edge developing things so what the LHC can do right today the back in the 1980s people no idea they'd be able to do it at the level that they can do it because Technology is developed one of the reasons they've been able to do it is that there was always a funding stream to help support the superconducting magnets to help support the development of the Accelerator technology the detector technology if you put that on hold right and said, okay Let's just let the theories have a go now for a while until we come up with something What are these people going to do? They're not going to hang around. They're not going to play say yeah, this is okay Let's just there is take about five years. Let's go and do something else They're going to leave and the subject and the runs the real risk. It is an expensive city It's like Apollo they will leave and that's it. It'll be the end of it And and okay, if you if you prepared to accept that so be it that that's the nature of it there is one possible route through I And I think Cerner are playing this They're playing for two possible scenarios here There's another one, which is that although they've come out with this future Collider circular Collider paper And I personally think it's really exciting they've also is sort of at the same time come up with it with another set of papers where they're looking at actually what it Can we make use of what's around CERN at the moment to actually probe different types of physics, which would still be looking at underlying fundamental physics of our universe but not Requiring, you know? Really high energy particle collisions? And this is motivated partly by the fact that we've not seen any evidence of dark matter we've not seen these massive doubt matter particles and maybe What what is actually going on in the universe? these equivalent dark matter particles aren't very massive, they're maybe really light and They don't interact very much with us in which cases having a big heavy Large Hadron light Collider won't be the way to see them. We need more sophisticated Ready-made precisely-made detectors to pick up some of these lights particles like axions specific axion detectors and so one possibility is to actually look at and for a set of experiments That could be based around CERN using the the accelerators They've already gots and using some of the facilities they've already got so just bout better experiments under the existing ring They use it. Yes, so they use up I'd bolts is a thinking of it and gently place existing expect, you know, you use what you've got and then lots of us Go that was so exciting. And and of course you're building new things as well, but that's well. That's that's another possible and So why ever said that I could imagine? the community saying Okay Let's have this period where we go that route for a little while Let's keep the R&D going for the for the big accelerators But during that period we can be probing testing these these models of weak coupling regimes like dark matter particles screening mechanisms, which could account for you know the fifth force that Could be driving the accelerating universe But meanwhile carry on with its R&D invest in the R&D for the future accelerators And then hopefully some results will come out of these New set of proposals or some theoretical developments will emerge which say yeah. This is the way we should be going and Then you can sort of decide Ok Now we'll start the process on but there is always this risk back in the 80s people were absolutely certain I think a pretty certain about that not absolutely but fairly certain that WIMPs were the way forward and that supersymmetry was the way forward There was no question to build the Large Hadron Collider after the large electron positron Collider It was it was just the thing to do and it turned out not to be right It's er it who knows? That's the Excitement's of many ways of working in these kind of fields. What would you do, Ed? Because obviously you're biased yeah, but you do live in a world where you are also like, hospitals and potholes to be built, and your children are going out to the world that need infrastructure How do you think the money should be spent so it's a lot of money and I would spend it and I because for a number of reasons one is You know, it's not just the UK contributing to CERN. CERN has got 22 members It's got I don't know eight affiliated members, you know, there's 30 countries here will all contribute They'll contribute over many many years. Okay, it's not as if this is an immediate out-lay, so there's a dispersion of the actual finance. Of course hospitals need all the facilities they can but, you know particle physics live in hospitals right my you know my dear father who passed away when I went to the city hospital for him to have Radiology treatment. On the wall, is this amazing plaque, I've tried to find an image of it that talks about the cyclotron accelerator that they were using and The and that's that was the particle physics of the forties thirties forties fifties that is now in medicine the MRI scanner that was invented here at, here at Nottingham Uses technology from the physics environment where there was purely for research that is now been bedded in in hospitals all around the world medicine needs Funding in its own, right? Of course it does but it's had so much input from fundamental ideas fundamental physics ideas for a start and chemistry and radioisotopes that everywhere in medicine that to simply Simply say yeah we should be putting all of this into medicine for example is Not the way to make the major breakthroughs that will help people in the future in medicine either What makes us special what makes us special is our inquisitive nature. We want to know about the universe. We want to know about beautiful pictures and admire them we want to know about what makes the universe tick. And we should have the facilities to be able to invest in all of these
This is the best piece of popular media I've seen on this subject, as expected from Sixty Symbols.
One criticism I do have is the bit in the end: he seems to imply that people who don't argue for the next collider don't want that money going in to science at all, when the question here is more whether or not this specific project is the most efficient use of the money that goes into science. That seems like a reasonable question to ask to me.
(Nima Arkani-Hamed did actually raise some good points about whether we should treat this as a zero sum problem, but all this sounds a bit MMT-ish and I don't know enough about how funding large projects like this exactly works to have a well informed opinion on this.)
When the interviewer asked if the money wouldn't be better spent in hospitals for example, Ed quickly said that, well, hospitals benefit from particle physics too! I nearly broke into applause.
Greeks : “Knock that shit off.”
Just build one on the moon. New scope of data, huge humanity project which will boost morale and make a step forward in space population. Should be our manned base on the moon.
Hey, my old lecturer! He was awesome.
ELLHC?
Hossenfelder's complaint is validated once again.
You don't build a 100km tunnel in the ground to "grope in the dark" for a scientific accident.
is this fair though? I love physics and it would be awsome to solve the biggest mysteries of the cosmos. but how about other issues? doesn't fusion deserve more investment for example?
The LHC did not only discover the Higgs. It also discovered that QCD is interesting. That includes new resonances that are in fact "particles".
There is a lot to understand in the nonperturbative sectors of the standard model. The most promising models to decipher these sectors come from quantum gravity and string theory. The LHC community is slowly but surely realizing that these ideas are sound scientific motivations. Maybe 50 years ago people said this is too difficult to tackle, maybe we have matured enough to have the courage now.