P5 Report

There is a HEPAP meeting going on today, with release of the long-awaited P5 report prioritizing future HEP spending. The report is available here now, to be officially unveiled later in the day and discussed at the HEPAP meeting. The muon collider as a future project gets a strong endorsement as the “muon shot”.

The full report is now available here.

See press coverage of this at Nature and the New York Times.

There will be continued discussion of the P5 report at HEPAP tomorrow, and at a Town Hall at Fermilab on Monday.

While the theory side of HEP in principle is part of this report, the attention to theory is minimal, with the report recommendations about theory, in total:

  • The substance-less “Enhance research in theory to propel innovation, maximize scientific impact of invest-
    ments in experiments, and expand our understanding of the universe.”
  • A more substantive call to give university theorists on DOE grants more money, with no attempt to prioritize what the money would be for:

    Increase DOE HEP-funded university-based theory research by $15 million per year in 2023 dollars (or about 30% of the theory program), to propel innovation and ensure international competitiveness. Such an increase would bring theory support back to 2010 levels. Maintain DOE lab-based theory groups as an essential component of the theory community.

    In the page or so of text about theory, the emphasis is on the phenomenology part of theory in contact with experiment. About formal theory there is just

    Theorists uncover the mathematical patterns that describe the universe and explore alternate mathematical universes to deepen our understanding of nature. Theoretical investigations into quantum gravity have unlocked connections between extreme space-time geometries and information theory. The perspectives theorists bring to particle physics play an important role in inspiring young scientists.

Update: Sabine Hossenfelder has her reaction to the P5 report here. I’m sympathetic to her critique that, as far as experiments go, the report is an argument for “more of the same”. But I’m not at all sympathetic to her alternative: “Personally, I think what they should do is spend some money on serious theory development” instead of funding experiments. If there’s a part of science where money spent by the US has been much more of a waste than in HEP experiment, it’s HEP theory, which is now pretty much intellectually dead. There’s a good argument that the way HEP theory funding works has been a driving factor in this fatal illness, so that the problem with HEP theory is not too little funding but too much.

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12 Responses to P5 Report

  1. p. says:

    “This less favorable scenario will lead to a loss of US leadership in many areas, especially the science of the G3 dark matter experiment, and will damage our reputation as a reliable international host for DUNE and as a partner for a Higgs factory. We still make investments in the future, but at a significantly reduced level for small-scale experiments, including ASTAE, theory, computing, instrumentation, and collider R&D. In this scenario, it would be increasingly difficult to maintain US competitiveness as an international partner in accelerator technology.” -p43

    Can someone explain please to an obvious idiot, WTF the USA feels the need to lead the world in this? Is there no comprehension about these folk that such a policy is seen as elitist, narcissistic, capitalist juggernaut? Or is that the deliberate intent? Or maybe you think the rest of the world is such a corrupt load of savages they need leading? Just curious

  2. Peter Woit says:

    I think you’re not understanding the nature of this report. It’s intended as a prioritization of requests from the US HEP physics community to US government agencies for funding. The intended audience is government officials, legislators, etc. who will be asked to approve large expenditures for HEP research. No one is going to try to make the case to a US congressman: “give us $1 billion/year so we can do research second in importance to what the Europeans are doing at CERN.”

  3. Amitabh Lath says:

    A couple of things stuck out for me: the report mentions muon collider research, as well as a “portfolio of small-scale and agile experiments”. I admit to being on the fence about the viability of a muon collider, but the idea of small-scale and agile experiments is exciting.

  4. tulpoeid says:

    Interesting comment in the press release about the report, by Hitoshi Murayama, P5 panel chair:
    “Our thinking about what dark matter might be has also changed [since the previous P5 process], forcing the community to look elsewhere — to the cosmos.”

  5. Peter Woit says:

    I was surprised that a CMB experiment is the P5 highest priority, had assumed that this was an issue for astronomy funding priorities, not HEP physics funding priorities. It seems one argument for this is the lack of a WIMP showing up at the LHC or in direct dark matter detection experiments means one should look is cosmology. I hadn’t realized cosmology experiment were getting funded out of the DOE HEP physics budget.

  6. anon says:

    CMB-S4 is (or at least was when it was discussed in the Astro Decadal Survey) supposed to be a joint roughly 50-50 split DOE-NSF effort. With the way (ground-based) astro funding is looking, it would never get built with only NSF money.

  7. Peter, I always thought that both your and Sabine’s opinions are equally bad. But it looks like Sabine is more reasonable than you.

    hep-th funding is very low. There are so many good researchers doing popular mainstream research, and after 6+ years of postdoc, they are forced to leave to Google/AnthropicAI, etc, and do some uninteresting high-paying job. If postdocs who work in mainstream approaches in top universities and get thousands of citations cannot get a job, obviously, nonmainstream approaches cannot get any job since it’s harder to compare and measure progress among nonmainstream postdocs. I hope I don’t need to share the inspire links of people who wrote very famous papers related to holography who had to leave the field in the last few years, as you probably know the situation. I think since you don’t like string theory/holography maybe you are blindly advocating for less funding. But if more funding is given nonmainstream approaches will also benefit, not just mainstream approaches.

    It seems you just want the entire hep-th field to die. I cannot understand what you will gain from that. Understanding fundamental physics is like the real purpose of humanity. It seems you are blaspheming against fundamental physics.

  8. Peter Woit says:

    “Photino Birds”,
    First of all, what’s with the anonymity and identifying as a weird sci-fi fandom site? How am I or anyone else supposed to tell the difference between a serious argument from an informed person and something unserious that should be ignored?

    If you are an informed person and this is supposed to be a serious argument, I’ll just point out that it’s not a very good one. You’re arguing that more hep-th funding is needed, to go to support the people adding to the 20,000 papers on the heavily overhyped topic of holography. Yes, there are too many such people on the market, so their job prospects are not great. What is needed though is not more funding to keep them doing holography, but redirection of current funding to other “non-mainstream” topics.

  9. JE says:

    Hi Peter,

    While I do not share Photino Birds’ view –or “shoot in the foot”– that holography can be a good example of non-mainstream physics that should (continue to) be supported with more hep-th funding, I think he has a case arguing against your comment that, “If there’s a part of science where money spent by the US has been much more of a waste than in HEP experiment, it’s HEP theory, which is now pretty much intellectually dead.”

    And more so when you say: “I was surprised that a CMB experiment is the P5 highest priority, had assumed that this was an issue for astronomy funding priorities, not HEP physics funding priorities.”

    First, because little or no sympathy for more/continuing hep-exp and hep-th funding can be fairly misinterpreted as “It seems you just want the entire hep-th field to die.” Perhaps you could explain where you would put taxpayers’ money more clearly to stake your case.

    Second, although I may be biased by my own research, there could be a deep, largely unexplored, connection between the CMB and hep-th. In other words, I can understand why CMB experiments can be among P5’s highest priorities. Or, more generally speaking, certain cosmological observations closely related to hep-th, which could shed more light on theory than big particle colliders (not including the muon collider, which seems quite reasonable an option) and at a much lower cost.

    And third, given the critical state of the field and the manifest inability of mainstream physics to find a solution, I would put my two cents in non-mainstream rather than mainstream physics, including outsider (privately-funded) research. Unlikely as you may think it is, if a lone researcher or a small group of privately-funded researchers came with a viable solution to the hep-th crisis, it would deal a big blow to the whole academic system. And perhaps with good reason.

  10. Peter Woit says:

    My comment about CMB was simply about the source of the funding. I would have assumed that microwave telescope funding would be categorized under astronomy, not DOE HEP.

    I’m writing more about this in the next posting, but my point about hep-th funding is that, with about 4000 hep-th arXiv submissions/year and order of magnitude 10,000 active hep-th researchers in the world, the problem with progress coming to a halt is not due to not enough funding. Yes, maybe some very different funding mechanisms would help, but no one is even discussing that, instead just asking for more of the same.

  11. JE says:


    Thanks for the clarification. Looking forward to reading that posting.

    Perhaps discussing these mechanisms could be worthwhile. More “non-mainstream” research could be needed after so much mainstream (at least until mainstream theory becomes non-mainstream, as it happens to be the case with holography now, according to some sources). This may suggest that the difference between mainstream and non-mainstream can start to become unclear after the debacle of string theory.

    So I would rather talk about promising lines of research -mainstream or not-, which better be publicly-funded.

  12. JE,

    The tides are shifting in that direction, holography becoming non-mainstream. Recently, Eran Palti (swamplander) https://x.com/EranPalti/status/1740626727490248743 noticed this. Several people who usually work on AdS/CFT toy models have gone back to doing proper string theory this year. In the last 10 years, most people worked on holography toy models and proper string theory was not popular. Exactly solvable models like JT gravity taught many things, but they are not UV complete. People always knew that these toy models were temporary. There is only one UV complete quantum gravity we know: perturbative string theory. So it is not far fetched that proper string theory will again be the hot topic in the future, as it is still the most promising theory. Using AdS/CFT as a nonperturbative definition of string theory is a cop-out. People must find an independent nonperturbative definition of string theory using new techniques and try to prove the AdS/CFT correspondence. PhDs and postdocs must do what is popular now. Research in proper string theory in the last 10 years was not good for postdoc opportunities, etc, due to sociology but that might change soon.

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