Various news about a possible future collider, all pointing to the CERN FCC-ee as the leading proposal.
- For up to date background technical information on proposed colliders, including cost estimates, see here.
- The Chinese CEPC plan is now on hold, as a decision was reached to not include it in China’s plans for the next five years (2026-30).
- As part of the European Strategy for Particle Physics update process, recommendations drafted earlier this month have now been released (see here and here). As expected, the main recommendation is to pursue the FCC-ee project, which will cost an estimated \$18 billion dollars or so. The fall-back recommendation in case this is too expensive is rather odd. People were expecting such a fall-back to be some sort of linear collider, which would cost half as much. Instead the fall-back recommendation was for essentially the same FCC-ee project, saving just 15% with various cuts to its capabilities. There’s a reaction to this from the linear collider people here.
- CERN today announced that private donors have pledged \$1 billion towards the FCC-ee project.
CERN will not make a final decision on this until 2028. I’ve always been skeptical that there is a viable financial path to funding a \$15 – \$20 billion new collider. Perhaps in our new world order where everything is controlled by trillionaire tech bros, the financing won’t be a problem.
Dr. Woit,
In light of this specific path chosen by the Europeans, what are your current, personal thoughts on the muon collider proposal for the U.S.? It doesn’t seem like the funding environment will be favorable to one until 2027 (after the midterm legislative reshuffle) at the earliest, and, even though it was slightly before my time, I’m still a little cautious from the story of the SCSC attempt. Personally, the muon approach seems to be the kind of ‘outside-the-box’ thinking we need, and I know a few people out my way who are pushing for it and doing good work on it, but my work is also in computational astrophysics, so I’m not close enough to it to trust my judgement.
Jesse Lee Buffaloe,
The muon collider proposal is a very different story, since there the problem is that there’s challenging new technology that needs to be developed. This requires funding, but at a much more modest scale than building a 100km tunnel. The whole science funding situation in the US is currently so bizarre that it’s hard to guess whether the needed research might be funded here. For the tech bros, this would be pocket change, maybe one of them will fund it…
Dr. Woit,
What are your thoughts of CN Yang’s “The feast is over” comment, which played a role in discouraging the China goverment from supporting Yifang Wang’s CEPC plan?
PZ,
I don’t really know much of anything about the situation in China, specifically have no idea how much effect Yang’s opposition had. Surely it didn’t help.
The problem with these proposals for a very large ring, both in China and in Europe is that the cost scales more or less linearly with the size, so these are very expensive to build. In addition, unlike the LHC, there’s no guarantee at all that there will be anything new in the energy range they can access. Yang wasn’t the only one among physicists to feel that this is not worth doing at this cost.
Not sure that LEP on steroids is the right thing although “cheap”, less risk and we know how to do it. The muon collider could probably achieve more interesting results. Europe, US and China should cooperate instead of compete.
Somehow deciding now is premature without seeing HL-LHC in operation. If HL-LHC gives no new pointers to new physics then this field is probably dead and the standard model wins. There is plenty of anomalies found but where do they point and could we be sure there is something to be discovered.
If no more accelerators then it is the end of high energy particle physics. We leave it to the astronomers to extrapolate the universe. Building colliders take an ecosystem of companies and when that is gone then the ability to build these is probably gone forever. The software and electronics is decades of evolution and the knowledge is in the mind of the people. When they are gone the field is dead. A future generation of humanity may return to building colliders but the price is likely to be prohibitive so it will probably never happen. It is the end of the conquest to understand the small.
Your CERN link says: “We’re proud to support the creation of the most powerful scientific instrument in history”. But LHC probed much higher energies than FCC.
It says: “The technologies emerging from this [FCC] project could benefit society in profound ways, from medicine to computing to sustainable energy”. But the more precise FCC measurements of Higgs couplings will have no practical application. The Higgs and the other particles discovered by high-energy physics in the past half century decay so fast that they found zero practical applications.
“une fois n’est pas coutume” (as one might say in French) some relatively positive news to be taken with caution and with a good dose of skepticism, e.g. wrt donations, IMHO. But it is a progress overall and I do like it. Thank you for posting this update.
Peter Woit wrote:
“In addition, unlike the LHC, there’s no guarantee at all that there will be anything new in the energy range they can access. ”
I’m honestly surprised that any scientist would critique a proposal for a scientific experiment to explore a previously unexplored frontier on the basis that it’s not guaranteed to make a discovery.
David Nataf,
What’s at the heart of the debate here is the cost/benefit analysis, and for this rational expectations about what we will learn from the FCC-ee are relevant.
If the FCC-ee was a \$1-5 billion project that could readily be funded out of the CERN budget there would be a very strong argument for doing it. But my concern is that I haven’t heard what the plan is for where the $18 billion are going to come from. If Jeff Bezos is going to provide it, forgoing his next generation yacht, that’s great. If it’s going to come out of defunding and mortgaging the future of a wide range of other scientific activity, that’s a different story.
The budget is a problem, huge problem indeed, but even more might be the human resources and the young physicists’ generation committing with enthusiasm to such a long-term project. In the communication strategy, which CERN and other great HEP Labs are definitively improving, there is IMHO a sense in also emphasizing, next to the fall back to society (the case is there, according to studies, e.g. https://home.cern/news/news/cern/society-benefits-investing-particle-physics) a “mission”, a re-committing, in a “post-truth World”, to the scientific objectivity, curiosity and the pursuit of Truth which goes beyond the careers and even life horizons. The brick contribution to building cathedrals as in the past has also been given as an example … with my apologizes for looking “naïve”. Of course the management needs to put in place the necessary HR frameworks. Re budget, “donations” are welcome but you need to be skeptic, validate and be cautious with potential “fine” prints.
I believe I’ve read (perhaps here) that eschewing a new collider to probe the energy frontier would lead inevitably to the extinction of a population of physicists and technologists with first-hand knowledge of how to build an operate such a machine. If thereafter a new generation of physicists theorized or discovered a compelling reason to build a next-generation collider, it would be extremely difficult to revivify that broken heritage. Perhaps so difficult as to effectively end the era of big collider physics. Is that a valid concern?
David Nataf,
This analysis is much too simplistic. I think it’s clear that whether you should build it depends on whether the chance of seeing something new and interesting is 50% or 0.1%.
Peter Shor,
I’m assuming that if we’re actually exploring the unknown we won’t know if it’s 0.1% or 50%.
Peter Woit,
I take your point about finite funding. In the long run I’m not sure if experiment physics she related science can survive at all given developments in political economy. I think of instruments like the LHC and James Webb as being like great cathedrals, but that doesn’t get built in a vacuum.
LMMI,
It’s a valid concern. The counter-argument is that, with the LEP/LHC tunnel size, circular colliders reached the limits of that technology due to fundamental physics reasons (synchrotron radiation) in the case of e+/e- and difficult physics/engineering reasons (limits on dipole magnetic fields) in the case of p+/p-. That we’ll no longer have people who know how to design and operate these kinds of colliders may be an unavoidable result of them reaching the end of their usefulness.
This argument though doesn’t apply to linear or muon colliders, so one reason its surprising this latest report doesn’t point to them as fall-back options to explore.
The main issue with funding future colliders is that while the price tag on even the cheapest of these is on the order of 10 billion dollars, the entire world budget on particle physics is about 3 billion (1 billion in the US, 1 billion in europe, and 1 billion everywhere else put together). Assuming one wants to continue to spend a large fraction of that on existing research and projects is how we get into the 20 year plus timeline for even the projects we know are technologically possible today (FCC-ee, linear e+e- collider at ~few TeV or less COM, somewhat larger and higher energy proton-proton machine).
For sure , for a scientific project that is a huge price tag. On the other hand, that is also the estimated cost of ONE of the proposed new “Trump Class” battleships. A sad statement about our priorities…