Thursday, February 21, 2019

Burton Richter on the Future of Particle Physics

Burton Richter.
[Image: NobelPrize.org]
The 1976 Nobel Prize was jointly awarded to Burton Richter and Samuel Ting for the discovery of the J/Psi particle. Sounds like yet-another-particle, I know, but this morsel of matter was a big step forward in the development of the standard model. Richter, sadly, passed away last summer.

Coincidentally, I recently came across a chapter Richter wrote in 2014 to introduce Volume 7 of the “Reviews of Accelerator Science and Technology.” It is titled “High Energy Colliding Beams; What Is Their Future?” and you can read the whole thing here. For your convenience I below quote some parts that are relevant to the current discussion of whether or not to build a next larger particle collider, specifically the 100 TeV pp-collider (FCC), planned by CERN.

Some of Burton’s remarks are rather specific, such as the required detector efficiency and the precision needed to measure the Higgs’ branching ratios. But he also comments on the problem that particle colliders deliver a diminishing return on investment:
“When I was much younger I was a fan of science fiction books. I have never forgotten the start of one, though I don’t remember the name of the book or its author. It began by saying that high-energy physics’ and optical astronomy’s instruments had gotten so expensive that the fields were no longer funded. That is something that we need to think about. Once before we were confronted with a cost curve that said we could never afford to go to very high energy, and colliding beams were invented and saved us from the fate given in my science fiction book. We really need to worry about that once more.

“If the cost of the next-generation proton collider is really linear with energy, I doubt that a 100-TeV machine will ever be funded, and the science fiction story of my youth will be the real story of our field [...]”
He points towards the lack of technological breakthroughs in accelerator design, which is the major reason why the current method of choice for higher collision energies is still digging longer tunnels. As I mentioned in my recent blogpost, there are two promising technologies on the horizon which could advance particle colliders: high-temperature superconductors and plasma wakefield acceleration. But neither of those is likely to become available within the next two decades.

On the superconductors, Burton writes:
“I see no well-focused R&D program looking to make the next generation of proton colliders more cost effective. I do not understand why there is as yet no program underway to try to develop lower cost, high-Tc superconducting magnets [...]”
About plasma wakefield acceleration he is both optimistic and pessimistic. Optimistic because amazing achievements have been made in this research program already, and pessimistic because he doesn’t see “a push to develop these technologies for use in real machines.”

Burton also comments on the increasingly troublesome disconnect between theorists and experimentalists in his community:
“A large fraction of the 100 TeV talk (wishes?) comes from the theoretical community which is disappointed at only finding the Higgs boson at LHC and is looking for something that will be real evidence for what is actually beyond the standard model [...]

“The usual back and forth between theory and experiment; sometimes one leading, sometimes the other leading; has stalled. The experiments and theory of the 1960s and 1970s gave us today’s Standard Model that I characterized earlier as a beautiful manuscript with some unfortunate Post-it notes stuck here and there with unanswered questions written on them. The last 40 years of effort has not removed even one of those Post-it notes. The accelerator builders and the experimenters have built ever bigger machines and detectors, while the theorists have kept inventing extensions to the model.

“There is a problem here that is new, caused by the ever-increasing mathematical complexity of today’s theory. When I received my PhD in the 1950s it was possible for an experimenter to know enough theory to do her/his own calculations and to understand much of what the theorists were doing, thereby being able to choose what was most important to work on. Today it is nearly impossible for an experimenter to do what many of yesterday’s experimenters could do, build apparatus while doing their own calculations on the significance of what they were working on. Nonetheless, it is necessary for experimenters and accelerator physicists to have some understanding of where theory is, and where it is going. Not to do so makes most of us nothing but technicians for the theorists.”
Indeed, I have wondered about this, whether experimentalists even understand what is going on in theory-development. My impression has been that most of them regard the ideas of theorists with a mix of agnosticism and skepticism. They believe it doesn’t matter, so they never looked much into the theorists’ reasoning for why the LHC should see some fundamentally new physics besides the Higgs-boson. But of course it does matter, as Burton points out, to understand the significance of what they are working on.

Burton also was no fan of naturalness, which he called an “empty concept” and his judgement of current theory-development in high energy particle physics was harsh: “Simply put, much of what currently passes as the most advanced theory looks to be more theological speculation, the development of models with no testable consequences, than it is the development of practical knowledge.”

A wise man; gone too soon.

15 comments:

  1. Nice post Dr. Sabine.

    Burton Richter's generation must have had a sorcery of some special genius.

    This anecdote from Abdus Salam is golden (about supersymmetry and beauty):

    "Dirac said to me, if this theory is true, it would have been discovered long ago."

    I strongly recommend the conversation:

    https://youtu.be/AmUI2qf9uyo?t=253

    The time label in the link is where the above anecdote nearly starts but the full conversion is also bliss.

    ReplyDelete
  2. I clicked on the "here" link and saw the error message below in Pale Moon, Firefox, and Chrome... Visiting the site by shortening the url I found that you have to purchase the article,
    "Access content
    To read the fulltext, please use one of the options below to sign in or purchase access.
    Personal Login
    Purchase Save for later
    ISBN: 978-981-4651-48-6 (hardcover) $108.00
    ISBN: 978-981-4651-50-9 (ebook) $43.00
    ================================================
    error message

    "The page isn’t redirecting properly

    Pale Moon has detected that the server is redirecting the request for this address in a way that will never complete.

    This problem can sometimes be caused by disabling or refusing to accept cookies.

    ReplyDelete
    Replies
    1. Mike,

      The link is working fine with me and I get no purchase request without institutional login, so I think it's a problem with your browser setting, not with the link. In any case, there's an arXiv version here.

      Delete
  3. O.k., so then let's just stop doing HEP, there are many other research fields worth pursuing.

    ReplyDelete
    Replies
    1. ... or we come up with some new ideas. If you look at what neutrino physicists do, they just set up a detector and wait. Wouldn't that be an alternative paradigm for HEP? What I have in mind is setting up a detector on the moon and wait until a high energy cosmic particle hits it (e.g. a 1 PeV particle !!!). Does that makes sense ? (Couldn't find anything on Google, but I found this: https://www.sciencedaily.com/releases/2018/08/180809112435.htm)

      Delete
  4. Frank Herbert (Author of Dune) and David Zindell (Author of Neverness) are two science fiction author who had some interesting insights into how science might be regarded in the very far distant future.

    Frank Herbert believed our own technological curiosity would eventually lead to our own enslavement from AI, and that the cost of breaking free from this would be that humanity would need to take control back from the machines by limiting how much we allowed technology to surpass our own understanding, divesting ourselves of many of their benefits and becoming more socially primative, and in some sense becoming our own computers once again.

    David Zindell took another path. He speculated our computers would become our gods (moon sized computers acting like neurons connected across star systems by networks of tachyons), and humanity would separate the sciences into guild like religions and mystical orders of mathematicians and technicians, each jealously holding dogmatic pieces of fragmented knowledge too great and too specialized for any individual to really have any overlapping understanding between specializations. In addition, he guessed that the AI gods humanity built would themselves follow their creators into conflict over resources and ideology, with AI star killing wars spanning thousands of years and millions of solar systems.

    Both visions offer interesting speculations about what happens psychologically and sociologically when the body of scientific knowledge eclipses the ability of people to comprehend it.

    ReplyDelete
    Replies
    1. I am rather skeptical of the AI claims we can generate conscious entities in computing systems. For one thing there is a sort of Pinocchio problem in being certain any AI system is conscious, even if it passes the most rigorous Turing test. Biological organisms and neural systems such as brains function very differently than computers. Computers fit far more in the Cartesian order of things with ideas of some created structure that sets a system in motion. Biology is really Darwinian with natural selection processes that from the nuts and bolts up generate organisms.

      The danger with computers is that we will become lost in our own virtual worlds, where we have no clear idea of what is ontologically real and what is a digital fantasy. I think with the media and some of the odd-ball politics of late we are getting an early taste of this. Also robotic systems could becomes little kill-bots that pose a growing problem. Computer systems are not what was envisioned decades ago as these truth oracles, but may in time be far more in the way of "lying machines" that increasingly lead all of humanity into ever more delusional domains of nonsense.

      Delete
  5. Hi Sabine:

    Great, insightful post, as always.

    I believe the disconnect between Theorists and Experimentalists goes both ways. As you mentioned, Experimentalists look at theory with suspicion. On the other side, (some) Theorists look upon experiments with little interest. It is this detachment from the empirical side of their discipline what may have led (some) them to the rollercoaster of baseless, speculative sciece of the last decades.

    ReplyDelete
  6. I find it amusing that at the bottom of this blog there is a big announcement "Quantum Space Elements, Is this the theory of everything in Physics?"
    Even though S. Hossenfelder can't find the ultimate theory, Google Ads can!

    ReplyDelete
  7. Richter points out the problem of accelerator physics having underfunded next-generation R&D on a gamble that the findings of the LHC would make higher-energy colliders of the current style easier to fund. Like seemingly everything else in experimental high-energy physics, the people pushing for advanced accelerators are organized into a committee and issue plaintive reports asking for the rest of the community to get on board and give them some money to experimentally address the various technological hurdles. Here's one such from 2017: http://www.lpgp.u-psud.fr/icfaana/ANAR2017_report_r.pdf, claiming a 2030 target date could be achieved for a technical design report. I'm not holding my breath.

    ReplyDelete
  8. What is lacking about increasingly more powerful accelerators is the combination of futuristic technology with futuristic physics of particles.It should not be just the often heard issue of a more and more powerful collider. There are lots of hidden and new physics with quarks, electrons, protons, glons. There is a hidden world that requires a critical assessment before conceiving what the future requires in terms of accelerators.

    ReplyDelete
  9. What Richter points out is something that depressed me early on. It was very clear that one can't really be a theoretical and experimental HE physicist. In many ways the complexity complained about with pure theory is similar with experimental physics that involves extremely sophisticated methods and technology.

    ReplyDelete
  10. "I do not understand why there is as yet no program underway to try to develop lower cost, high-Tc superconducting magnets [...]”

    There is!

    ReplyDelete
  11. Sabine, have you looked into advanced accelerator technologies other than plasma wake-field? There are more near term technologies (like dielectric wake-field accelerators) that do not have as many problems to solve as plasma wake-field accelerators. Perhaps those techniques should receive priority for funding, so that a more reasonable collider could be built.

    ReplyDelete
    Replies
    1. The 2027 report I linked above goes into great comparative detail about four main categories of advanced accelerator technology, including dielectrics.

      Delete

PLEASE READ THE COMMENT RULES BEFORE COMMENTING.

Comment moderation on this blog is turned on.
Submitted comments will only appear after manual approval, which can take up to 24 hours.
Comments posted as "Unknown" go straight to junk. You may have to click on the orange-white blogger icon next to your name to change to a different account.