# Project X and Flavor Physics

Last week Fermilab hosted two workshops on the so-called Project X proposal for building a linac designed to produce a high-intensity proton beam. The first workshop dealt with issues surrounding the proposed accelerator itself, the second with the physics that it might be able to investigate. Project X is being discussed in the context of an increasing realization that prospects for the ILC getting approved and built anytime soon are slim, so the US particle physics community in general, and Fermilab in particular, need to have a viable plan B for what they will be doing during the next decade. DOE secretary Ohrbach, in a recent talk at Fermilab made it clear that he thinks the ILC project is still at the stage of an R and D project, not yet near the point where a decision about it can be made and a full engineering design developed. For commentary about this from Barry Barish, director of the ILC project, see here.

One argument for Project X is that it would help develop some of the linac technology needed for the ILC, but the main arguments for the machine revolve around a striking change of direction for US particle physics, from the use of colliders to do experiments at the energy frontier to fixed-target physics at lower-energies. In some ways this would be a return to the older style of particle physics experiments that was the norm before the era of colliders. The point of Project X would be to produce a beam capable of being used to generate more intense beams of neutrinos that could contribute to neutrino physics, and to do what is now often called “flavor physics”. This is the study of phenomena involving heavy quarks and/or rare decays, with the hope of seeing beyond the standard model effects that occur not in lowest order approximation, but in higher order contributions to decay rates. There are quite a few decays that one can look for that either can’t occur at all in the standard model, or only can occur at unobservably small rates. An observation of such a decay and measurement of its rate would provide evidence of new physics. Many such studies already conducted provide strong bounds on quite a few possibilities, so one can imagine competing with colliders such as the LHC to either rule out or find new TeV-scale physics by doing this sort of experiment.

One interesting document to read about this is the account of a panel discussion on charm physics that occurred this past August. A participant emphasized how history has recently been running against the people working on flavor physics, telling the following story:

… over lunch we were talking about the future of the field, and I was drifting off, and ended up in a fantasy world where things were done the right way. And in this world the LHC was in fact built and came on the air, and found the Higgs, and found many new events that we couldn’t explain with the Standard Model. And people had realised that in order to interpret these possible signals of new physics, we would also have to have flavour physics studies of rare phenomena, so that we could start to see patterns emerging… and working symbiotically together, the LHC and the flavor sector would get to the root of what was happening, something that would be very difficult if not impossible to do with the LHC alone.

But then I woke up. And I thought about a colloquium I’d given recently, where one of the chief experimentalists there took me into his office and shut the door and said to my face, “Flavor physics is dead!” and apparently he’s not the only one who said it: some pretty important people have said it. And when something like that is said over and over it begins to have a truth of itself.

Deciding whether Project X makes sense will require figuring out exactly what kinds of experimental results it will make possible that would not be possible using existing or currently planned facilities. For more about this, see the introductory and wrap-up talks by Joe Lykken and a talk by Jon Bagger that summarizes the issues well. The workshop also featured an excellent talk by Michelangelo Mangano summarizing the current situation of particle physics, emphasizing what it might be possible to learn through other means than the LHC, which is what is getting almost all the attention these days. He pointed to the activities of the CERN Working Group on the Interplay Between Collider and Flavour Physics that are documented at this web-site.

Update: Alexey Petrov was at the Project X workshop, and has a very interesting posting about it.

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### 35 Responses to Project X and Flavor Physics

1. Flip says:

Thanks for pointing us to the workshop PW!

A quick note: streaming video of most of the talks are available at the Fermilab VMS site: http://www-visualmedia.fnal.gov/VMS_Site_2/

Click on “streaming video archive” and search under series: “High Intensity Proton Source.”

Cheers,
F

2. Peter Woit says:

Thanks Flip!

Personally I can’t stand watching videos on the computer, and only will do this if there are no slides available, or if I can’t figure out from the slides what the speaker was talking about. Maybe this is a generational difference, or maybe I just have the short attention span young people are always accused of having…

3. Dave Miller says:

Peter,

In a time when hundreds of billions are going down the tube in Iraq, it’s easy for us physicists to think that of course we should be given a few billion (or is it a few dozen billion?) to build the next accelerator.

But this is real money — it could be used to build a lot of libraries or hospitals (or pay for a lot of mathematicians or theoretical physicists or a few new football stadiums or…). Is there any credible case to spend it on a new accelerator?

My Ph.D. is in particle theory from Stanford (SLAC), and I actually knew Barry Barish when I was an undergrad at Caltech, but I have since moved into other fields. Even from my perspective as a former insider, I am only mildly curious about the results that will be coming out of the LHC (curious enough to follow your blog, of course – thanks for all the effort you put in). Why should we expect our fellow taxpayers to fund a machine, the results from which do not interest most people and indeed which most people cannot even understand?

You have a rather unique view and position in the field of physics. Looked at objectively, can you think of any reason our fellow taxpayers should fund Project X – except of course to keep physicists employed?

All the best,

Dave

4. chris says:

hi dave,

“can you think of any reason our fellow taxpayers should fund Project X – except of course to keep physicists employed?”

when i hear this kind of argument, it always reminds me of that famous story about faraday. when asked by the king what good his novelty experiments on electricity were he responded by saying, that one day there will be taxes on it.

seemed pretty outlandish then, right? seems pretty outlandish now to hope for anything relevant to be discovered at a new accelerator.

5. Roger says:

Dave has a point. There is a feeling here that this is something just to keep people employed. The physics involved in project X is reasonably interesting but, in the absence of discoveries of non-Standard Model physics at the LHC, may just be more of the same fare we’ve been served over the past few decades.

This is an issue not only for Fermilab, but concerns the whole field of experimental particle physics. The most recent advances in fundamental physics have come from the astrophysics experiments – is this a trend for the future ?

If the LHC provides no surprises I can see good not not compelling arguments for further investment in large scale collider experiments.

6. Roger says:

Dave has a point. There is a feeling here that this is something just to keep people employed. The physics involved in project X is reasonably interesting but, in the absence of discoveries of non-Standard Model physics at the LHC, may just be more of the same fare we’ve been served over the past few decades.

This is an issue not only for Fermilab, but concerns the whole field of experimental particle physics. The most recent advances in fundamental physics have come from the astrophysics experiments – is this a trend for the future ? If the LHC provides no surprises I can see good not not compelling arguments for further investment in large scale collider experiments.

7. chris says:

roger,

i think what we have seen over the past decades is the other fields catching up while hep-ex is – comparatively – starving. until basically the 80s politicians funded this field because of the perceived relevance for nuclear devices of whatever sort. now that it is clear that the results are not anymore directly relevant and biotech is the current cool technology, funds have decreased accordingly.

i am fully in favor of any alternative way to learn about fundamental physics and indeed the astrophysics results of the last decade are impressive. but ultimately, if you want to know the physics at a certain scale, you have to go there somehow. and that costs and therefore it is slow. but i do not see an alternative. except of course if we just decide that we don’t care at all.

8. Dave Miller says:

Chris,

Of course, I’ve always loved that anecdote from Faraday (what physicist doesn’t?).

But I’m skeptical that it is relevant any longer. Elementary particle/ high-energy physics has been around for a long time now. But no practical result has ever come from it, nor is there any on the horizon. And there seems to be an obvious reason for this — charmonium, the W/Z particles, the higher baryon resonances, the tau lepton, etc. are so massive and so unstable that it is hard to see what role they can ever be made to serve in everyday life.

Of course, it is always possible that when Lubos finds the complete solution to superstring theory that this will lead to countertop antigraivty and baryon non-conservation (which would provide an unlimited energy source).

But in all honesty, can you envision in your wildest dreams any practical result from particle physics in the next century? Faraday could (and did) accurately envision such results from his work, as the famous anecdote shows. I’ve been thinking about this (occasionally!) for more than thirty years since I was an undergrad — I still remember George Zweig’s idea of using muons to catalyze fusion — and I cannot think of any plausible practical consequences.

Do you honestly think high-energy physics will ever “pay off” in practical economic terms (not counting as a physicists’ full-employment program)? Practical results are not the only reason for science, of course, and we all have a perfect right to pursue our hobbies and interests on our own time and money. But is there any honest reason to urge our fellow taxpayers who lack our interests to spend tens of billions on this?

Dave

9. Peter Orland says:

Dave Miller (who I used to know a bit when I’d visit SLAC during the
summers) raises an important issue. I think this is the central reason
why physicists should popularize their work with as little dishonesty
and hype as possible.

I think we can get the public interested in what we do thereby persuading them that funding experiments is valuable. It’s
important, though, that they not be lied to in the process, since they will not readily forgive us. NOTE: The space station and the space shuttle, devoid of scientific or technological value, can get away with such dishonesty – they have much larger budgets and a military connection.

10. Dave Miller says:

Peter Orland,

One of the main virtues of our host (Peter Woit) is that he does urge such honesty.

I remember when I was a grad student at SLAC that it was sort of a joke (openly discussed among faculty) that the only reason we were funded is that the feds were hopeful/afraid that we’d come up with another weapon like the nuclear bomb. Everyone laughed about it because we knew it was unlikely, but there was a consensus that no one should let the funding sources in on the joke.

Years later, a friend who had ties with the defense establishment told me that the feds weren’t that dumb but that they did view the HEP program as a good technical training program for people who would end up working on nuclear weapons, SDI, and more conventional military programs (which happened to a lot of my classmates).

While I do endorse complete honesty, I do suspect that we may find that our fellow citizens care a great deal more about Monday Night Football and Paris Hilton than about science.

Dave

11. Roger says:

Chris – I totally agree. Progress will best be made with collisions at the energy scale one wishes to investigate. However, the problem will arise if the LHC does nothing other than confirm that the SM is a great low energy effective theorem. In this situation, there is no clear guidance as to which energy scale one would need to probe to make progress. Rare decays are of course sensitive to physics occuring at high mass scales but, with the exception of the tenuous g-2_muon result, there is so far little to suggest anything exciting so far. To carry on trying in this area is a good but not compelling argument for further large scale investment.

I’m a collider physicist so my career is tied up in all of this. However, should the LHC not do anything exciting I would be tempted to change fields and move in an astrophysics direction where one is more likely to make progress.

Accelerators are a comparatively recent technique and it may be that they’ve had their day. It may also be that in a few years time we’ll be discussing some of the greatest discoveries mankind has ever made.

Slightly off-topic here and I hope Peter won’t delete this but I’m a little gloomy that the latter possibility will happen given that the “compelling” argument for new physics at the LHC is the hierarchy problem. I’ve never been convinced by this, possibly because I don’t appreciate it fully. Will someone explain to me why the hierarchy problem seems to have been elevated to “big problem” status and why it should be taken seriously ? I’m happy with the mathematics of it but it seems to rest of so many assumptions. To me, the strong CP problem or electric charge quantisation are “bigger” problems.

12. DB says:

This plan B sounds sensible. Whatever turns up at the LHC it is likely to be the Saturn V of our time. The LHC was sold on its ability to discover the Higgs, if it exists, whilst leveraging existing accelerator assets. Although it had a great case it was really touch and go on a number of occasions during the budget approval process. As things stands, neither the ILC nor CLIC can boast a similar clear-cut rationale and without it they will never see the light of day. Of course, the LHC may yet provide that rationale. However, even if the LHC astounds us, I don’t believe politicians have the appetite for yet more mega-budget physics.
As we have seen in recent years with Kamiokande and Sudbury and now Auger, the detection – be it terrestrial or space-based – of astrophysical sources of HEP particles will continue to see lots of action whatever turns up at the LHC. Solid, low-hype, reasonable-cost physics which delivers in spades.
(Well it used to be low-hype, but recently some idiots have begun to refer to UHECR’s (ultra high-energy cosmic rays) as “oh my God particles”)

13. woit says:

Dave,

I believe one motivation for “Project X” is that it’s a lot less expensive than something like the LHC/ILC, so can probably be built within the current level of US HEP funding. So, particle physicists don’t need to ask the public for increased funding, just a continuation of the current level. I happen to think that’s not hard to justify: it’s a very small fraction of government spending, has spinoffs, a small chance of dramatic breakthroughs that are technologically useful, but, most importantly, I think the effort to understand nature in this fundamental way is a worthwhile thing for humanity to be putting some of its resources into. While most people are not well-informed about particle physics, my experience is that most of them put it in a category of interesting things they wish they knew more about, and have no problem with a few dollars/year of their taxes being devoted to this pursuit.

The question about “Project X” I think is not whether it’s affordable, but whether the possible physics results it can achieve are worth it, in comparison with other ways of spending the money. That’s the question this workshop was devoted to looking at.

PW:

One argument for Project X is that it would help develop some of the linac technology needed for the LHC, but the

I guess this should be “ILC”? Great post!

DM:

But no practical result has ever come from it, nor is there any on the horizon.

I guess one reason why many countries are funding this kind of experiments, such as the LHC, is that lots of practical results are coming out from them. Not in the form of making a cure for cancer from the Higgs boson, of course, but as related technology developments. This blog is one among many, and probably the least important, such developments.

Even more relevant, today low-energy particle accelerators are being used (and commercially built) for a myriad of important uses: as sources of synchrotron light and low-energy electron, nucleon and ion beams for research in materials science, nuclear physics, biophysics, biotechnology and medicine. One of the hospitals in the city where I live is seriously considering buying one for cancer treatments. I have no idea what kind of accelerator or what kind of treatments this is about.

Yet, current commercial and non-commercial low-energy accelerators where one day developed as the bleeding-edge laboratories of particle physics. In a few decades the LHC might well be considered a low-energy machine for applied science. I’m sure more concrete examples can be given, maybe someone else knows what DESY is going to be used for now that HERA has been decommissioned. Germans are certainly not going to just demolish it……..

15. What’s wrong with oh my god particles ? I find it quite funny, unconventional, witty, and pulling the leg of Higgs nicknames aficionados. I do not think we should be concerned with over- or under-hyping our experiments. Catch-words are useful in that they lower the barrier with non-scientists and give some humorous side to things. How are we going to take the public on our side of the funding battle if we show disdain for popularization and trivialization of science ? Science is not ours, it is everybody’s.

T.

16. nn says:

Chris,

If your arguments about practical usefulness of science are correct where would that leave astronomy beyond the solar system? (I’m excluding the solar system because e.g. watching NEOs clearly
has a practical purpose — just ask the dinosaurs)

But it is arguably doubtful there will ever be any practical application
of astronomy at a larger scale or cosmology.

And some of the astronomy projects (like Hubble or Webb or the
larger earth based telescopes) were/are also quite expensive in
LHC scale.

But I still find the results very interesting (not being an astronomer
myself) and would be sad if it wasn’t funded anymore.

One advantage the astronomers have over the particle physicists
is that their results are generally easier to understand for
the layman. Perhaps that is something physicists need to work
on.

17. Pingback: Project X workshop « Symmetry factor

18. Markk says:

Speaking as one of those taxpayers, not a professional academic, the reason to fund things like High energy physics are twofold.

First and most important is that these are things should be done in a society in which I am proud to belong. As a society, curiosity about our universe and seeking of knowledge about it, are part of the definition of being healthy. When we lose that, and stop spending the pittance we do on things like HEP, we are sick and not long to remain as a coherent society. This is the classic point that everyone from Hardy to Lederman and who knows how many others have made. We are not spending NIH style money on high energy physics even if we would have built the SSC. You can make a point about funding levels, but that is a whole different administrative point, not an issue with goals.

Secondly, as a practical matter, as an engineer, and person who used to hire engineers, I think that we need to keep a bank of knowledge of people who are doing research at the frontiers and can reproduce old research. Somebody who people can turn to for that little bit deeper knowledge and experience, when they have to.

As an example, lets say a SM Higgs is found and nothing else and no signs of anything else at LHC. Do we turn off all the colliders then? If so, then why don’t we stop teaching theoretical high energy physics – there is no point, we for sure then could never do anything with it and by the same reasoning it should go also. We lose the knowledge in peoples minds then. It might be in books, but that isn’t online in heads. Now suppose some odd results come in from, say materials, that indicate long lived particles or other odd behavior. We’ll have people from other areas that can jump in the research but there will be a gap, and people might not even notice it really, because there will be nobody with the theoretical background and nobody with the practical background to understand what is going on. I would say we’d end up spending a lot more money, and a lot more time at that point rebuilding the knowledge we would have had, if we even understand what we have in the first place.

19. Peter Woit says:

Thanks! Fixed.

20. chris says:

hi nn,

also to that i can only answer by going into history. i think it was around 1850, when in a prominent textbook on astronomy the composition of distant stars was listed as one of the things that can never possibly be accessible to humans.

my only answer is, who knows. how can you be so sure that what you find out there will not at one point in the future change our daily life.
just to give a particularly bad and uninspired example, how do you know that watching supanovae going off in distant galaxies in the full spectrum will not be a main tourist attraction of the 54th century?

21. chris says:

dear dave miller,

thanks for your long reply. i have only spend the last 1.5 decades in hep, so i grew up during the most boring of all times so to say. and yes, i do have similar doubts that results of any practical relevance in the mid-term future will come out of hep soon. and a third yes, i am also in it for the knowledge and not the technology, which is of course the motivation for almost every person doing hep i guess. but still. we are scratching at the frontier. per definition we don’t know what comes next. there are people who claim that at 1 TeV you start leaving our brane and go into the bulk of the universe. and this is just the result of wild speculations while idling and waiting for nature to tell us what is there really.

i can’t imagine any possible practical use of HEP within the next century except the spin-offs that i don’t really want to count. but again, if i knew what to expect, i wouldn’t do research. and after all, the periods in physics where everything seemd to be settled until now were followed by the most dramatic changes always. of course, one should not rely on this. but it still is possible i think.

22. Low Math, Meekly Interacting says:

I may be unusually interested compared to the average non-physicist, but this taxpayer, at least, is willing and driven to vote for politicians who promise (however obliquely) to give experimental HEP in the US a good financial boost.

If the theorists in the field are victims of the success of the S.M., they must at least be equally victims of having to wait about 20 years too long for TeV-scale accelerators.

That said, although I found Dr. Robert Wilson’s eloquent statements in defense of mere discovery both inspiring and moving, nothing seems to persuade the legislator and executive quite like fear. It’s hard to imagine the Apollo program without the Cold War. “We’re losing our technological edge to Europe, including the FRENCH!”, or the prospect of having to outsource nuclear research to China, might succeed where appeals to such frivolities as human curiosity may fail. The mere thought that China seeks to land a robot on the Moon seems to be enough to motivate our leaders to waste (in my opinion) $100 billion on human flights to Mars, so there’s a lesson to be learned, however sordid and cynical it may be. 23. nn says: chris, I think you’re misunderstanding me. I wasn’t arguing against funding astronomy. Just pointing out that if D.M.s efficiency/cost metric would be strictly applied astronomy would likely suffer too. And some other very interesting, but most likely also relatively useless areas of science (although admittedly most are not as costly as HEP or high-end astronomy). But it’s not a pure HEP issue; more a general science problem. Also there might be always uses for everything of course, although they are hard to predict. Standard example is number theory — which used to be considered 100% useless — makes public key cryptography and the internet go around these days. But then the number theorists also never needed any billion dollar toys to play around with. 24. srp says: I will once more shout down the well here. The bottleneck is current accelerator technology. If a substantial fraction of the resources proposed for ILC or Project X were allocated to basic technology development of wakefield accelerators, could they be deployed in a reasonable time frame? If the likely answer is yes, then that strikes me as the no-brainer strategy, since it allows much higher energies at affordable prices (and device sizes). Experimental particle physics is rapidly being painted into a corner; it needs to innovate a way to smash through the walls. As a taxpayer, I would be much happier paying for breakthrough accelerator research than for low-payoff conservative designs. If the physics community got behind this strategy they could appeal to a) the scientific superiority of ultra-high energy at affordable prices, b) the American love of invention, and c) the possibility of spinoff technology. Of course, if there were a sound argument that wakefield technology is scientifically unsound or technologically too hard, then this strategy would be a poor one. Yet I have found no such statement, nor, curiously, much interest in assessing whether this technology is truly promising. It’s like going for brain surgery before finding out if you can cure your headache by taking some aspirin. No commitments to any future accelerator proposals should be made until that wakefield assessment is made. 25. Peter Woit says: srp, It’s my impression that the sort of acceleration technology you’re talking about is nowhere near the development stage, but requires a lot more research to even see whether it is really feasible. There’s a good argument for putting more resources into that research, but it’s a very different thing, on a different scale in terms of money (less) and time (more) than the ILC or Project X. In those cases the technology is in place now, and the question is whether to spend the large sums needed to build a machine sometime soon (years, not decades). 26. Dave Miller says: Peter, Thanks for clarifying the cost issue on Project X. Chris, I think you’re thinking of Auguste Comte, the philosopher and founder of positivism: >We can never know what the stars are made of, Comte gloomily concluded in 1835: >>On the subject of stars, all investigations which are not ultimately reducible to simple visual observations are…necessarily denied to us… We shall never be able by any means to study their chemical composition. ( http://www.astrosociety.org/pubs/mercury/33_05/rainbows.html ) Markk, Having moved from academic HEP to emgineering work in industry, I’m a bit skeptical of the “keep a bank of people with knowledge around argument.” No one is suggesting that theorists be prevented from pursuing and publishing work in theory or that people like Peter Woit and I be liquidated because we still possess some knowledge of HEP. Assuming that we can continue to live in an affluent society with freedom of speech, etc., there will be people who continue to know and learn this stuff. The issue is simply why our fellow taxpayers should pay big bucks for bleeding-edge experiments. And, on that issue, srp’s point makes a good deal of sense to me. Do HEP experiments have to be this expensive? I understand the underlying physical reasons for the big accelerators, but do we also have a bit of a “NASA problem” here? Other countries (and now some private companies) have shown that you can put stuff in orbit a lot cheaper than NASA used to charge. Is it possible that srp is right and that we have gone for the immediate gratification of the big colliders and had too little deferred gratification aimed at accelerator technology development? Dave _____ 27. djm says: srp, There are many other “high risk, high payoff” technologies in accelerator R&D than just wakefield, and even more low risk, lower payoff, some of which is being funded at a modest level through DOE, ILC, etc. It is a topic that could certainly be funded better. There is a distinct sense from ILC meetings I’ve attended that they don’t want to talk about possible accelerator technology breakthroughs, because it could interfere with selling the current design. IOW, if a breakthrough may be 5 years out (which it always could be), why not wait for that and redesign? Current technology is impressive but has a distinctly brute-force flavor, which does not appeal to those of us who have made clever technology work in other contexts (e.g. at lower energies). 28. djm says: Dave Miller: “Other countries (and now some private companies) have shown that you can put stuff in orbit a lot cheaper than NASA used to charge.” Every successful orbit to date has been entirely or largely subsidized by a large government with enormous resources. Yes, it is cheaper to launch from Kazakhstan than Florida. 29. srp says: djm: I just mentioned wakefield because I’ve heard of it. If other stuff looks like it might be better, then resources can be put into parallel projects. An intelligent research program in accelerator technology development obviously should allocate resources to multiple paths until one emerges as the best option. The behavior you describe in ILC meetings, where people don’t want the possiblility of breakthroughs to deter investments in the here and now is pretty common in all large organizations. It’s even rational in many cases. The current situation is not one of those cases. Given the current context–a dead end for conventional accelerator technology with marginal rationales being cooked up just to keep the game going after the LHC–it would make sense for the physics community to get behind advanced accelerator technology development the way it now gets behind conventional behemoths like the ILC or Project X. This is one of those rare situations where investing in the cool new cutting-edge stuff is more fiscally, politically, and scientifically responsible than sticking with the tried and true. 30. wb says: srp, The real promise of wakefield accelerators is in the range of 1 – 100 GeV where light sources can become university laboratory tools and where multi-spectral beams can be used to probe matter with femtosecond simultaneity. Once one is honest with oneself about building high energy colliders with such objects you do a calculation of the electrical power required for such devices. For all the charm about so-called compact size the power requirements come from very simple calculations of luminosity in terms of beam power. As a starting point note that at L=10^33 an ILC requires ~350 MW. Scaling to where a post LHC collider should really be (1.5 TeV in the c.m.), one see that a wall plug power of ~3 GW will be required. Be an optimist and imagine that lasers are 100% wall plug efficient and that wakefield accelerators will be as efficient as rf driven accelerators, and you may convince yourself that a post LHC linear collider will only require 1 GW of electrical power. There are many more practicalities that put TeV scale wakefield colliders far beyond what can be delivered in the next decade even if one can pay the power bill. Laser driven accelerators have made great progress and they do have great promise for accelerator based science that can be delivered in the next decade if that R&D funded at 2 to 3 times the present rate. Unfortunately high energy physics is not one of those promises. 31. srp says: wb: Thanks for your insights. The advanced accelerator community does not appear to see things the same way; see for example http://cerncourier.com/cws/article/cern/30148 where the author talks entirely in terms of high-energy physics applications and never discusses power issues (although he is worried about applying wakefield technology to positrons). This stance could be technological hubris or grantsmanship, of course–I think the tokamak fusion community has been accused of similar sins–but I need to explore the issue more thoroughly to know whether your dismissal is the end of the argument. 32. srp says: And this guy is talking about 10TeV with 360MW wall-plug power: http://www.bnl.gov/ATF/Meetings/AAC04/plenaryabstracts/Monday/GeraldDugan.pdf Of course, there are some feats of beam compression involved to get the desired luminosity, and I have no way of telling whether these are plausible. But if it took spending$100 million to find out, I’d support that.

33. wb says:

srp,

Gerry Dugan is certainly an expert and not one pushing his own research program in this talk. Look at his CLIC example. This has 30 MW of beam power. At 10% wall plug efficiency and accounting for overhead power for the facility, CLIC will need at least 500 MW. (note that is completely consistent with ILC estimates at 1 TeV. At 3 TeV CLIC also needs other miracles to actual maintian nanometer beams in collision in space and time. No one has demonstrated that such control systems can close the loop or are stable. Nonetheless, I agree that search for such capability is worthwhile. It will tell us the limits of are capabilities with linear colliders.

His 10 TeV system at 1e36 luminosity assumes an efficiency that is rather incredible. Despite the fact, that the present state of laser efficiency from wall plug to ultra-short pulse lasers is ~1% and that the efficiency from that lase pulse to a beam is also of that order, the stated ifficentcy to two significant figures is 16%. The beams must be controlled to 1 Angstrom in the vertical plane. I’ll have to think more about whether that last claim makes physical sense even.

The bottom line is that this technology will not be ready for 2025 even if R&D funding were increased many-fold. Fortunately the laser technology gets driven by commercial and defense interests. The only sure path forward to the 10 TeV mass scale is a very large hadron collider. Is that affordable? are we capable of managing a project of such large physical size? I’m not sure. I only advocate avoiding the hype and making sure that LHC and its upgrades give the very best possible physics output.

34. Howard Walker says:

Mr. Woit,

I have just finished “Not Even Wrong” and loved it. While it confirms my thoughts about String Theory, I was really quite pleased to see that professionals like yourself are coming out against it. I am quite angry though that so much money and time is being lost on this red herring and that it will not end any time soon as THEY are in charge.

If the TOE were to be announced tomorrow, THEY would say THAT is exactly what they have been saying all along and THAT IS what String theory really was all along. And THAT is what really bugs me to no end.

Please keep up the fight for real science.

Howard