UPDATE JULY 4, 2022
Questions [Joachim Mnich, CERN‘s head of research and computing]:
“Is the Higgs boson really a fundamental particle or is it a composite?”
“Is it the only Higgs-like particle that exists—or are there others?”
• Phys.org > “Large Hadron Collider revs up to unprecedented energy level” by Pierre CELERIER (July 4, 2022) – The new energy rate will allow them to further investigate the Higgs boson, which the Large Hadron Collider first observed on July 4, 2012.
The world’s largest and most powerful particle collider started back up in April after a three-year break for upgrades in preparation for its third run.
From Tuesday it will run around the clock for nearly four years at a record energy of 13.6 trillion electronvolts, the European Organization for Nuclear Research (CERN) announced at a press briefing last week.
After this [3rd] run, the collider will come back in 2029 as the High-Luminosity LHC, increasing the number of detectable events by a factor of 10.
Beyond that, the scientists are planning a Future Circular Collider—a 100-kilometer ring that aims to reach energies of a whopping 100 trillion electronvolts.
ORIGINAL POST FEBRUARY 6, 2019
I’ve encountered some articles recently about the current state of particle physics. Or, more broadly, “the direction of theoretical physics .” Concerns about its future. Whether new particle accelerators are needed (or even viable). An expensive rabbit hole. That research has become mired in wishful elegant mathematics. The absence of evidence being evidence of absence.
I didn’t record the first articles that I noticed on this topic. A footnote below , however, lists some examples of the negative sentiment.
In contrast, other articles (noted below) were optimistic about the situation.
• [Slate] Particle Physics Is Doing Just Fine: In science, lack of discovery can be just as instructive as discovery (January 31, 2019)
Recently, particle physics has become the target of a strange line of scientific criticism. … But the proposal that particle physicists are essentially setting money on fire comes with an insidious underlying message: that science is about the glory of discovery, rather than the joy of learning about the world. Finding out that there are no particles where we had hoped tells us about the distance between human imagination and the real world. It can operate as a motivation to expand our vision of what the real world is like at scales that are totally unintuitive. Not finding something is just as informative as finding something.
• [Forbes Senior Contributor Ethan Siegel] We Must Not Give Up On Answering The Biggest Scientific Questions Of All (February 5, 2019)
There’s an old saying in business that applies to science just as well: “Faster. Better. Cheaper. Pick two.” The world is moving faster than ever before. If we start pinching pennies and don’t invest in “better,” it’s tantamount to already having given up.
This morning, I noted that Chad Orzel weighed into the topic with an article summarizing the debate. He references some of the seminal posts.
• [Forbes Contributor Chad Orzel] The Thorny Question Of Whether To Build Another Particle Collider (February 5, 2019)
As I mentioned in that earlier post, though, this is a tricky topic to write about because it’s posing a genuinely difficult question about research priorities and resource allocation. As a result, while many of the arguments for and against are delivered with great passion and conviction, I don’t find any of them fully convincing. It’s just too easy to poke holes in most of the arguments being thrown around.
So, there’s a historical side to the topic — the struggle with prior “Big Science” projects. And a philosophical side — a debate about theory and scientific progress (which also has a long history).
 Examples of negative sentiment on research:
• [Vox] The $22 billion gamble: why some physicists aren’t excited about building a bigger particle collider: Particle accelerators have taught us so much about physics that the new one might have nothing to find (January 22, 2019)
• [NBC News] Why some scientists say physics has gone off the rails: Has the love of “elegant” equations overtaken the desire to describe the real world? (June 2, 2018)
• [Sabine Hossenfelder] How the LHC may spell the end of particle physics (December 27, 2018)
• [Sabine Hossenfelder] Particle Physics now Belly Up (June 23, 2018)
 Wiki: Relationship between mathematics and physics
“At this point an enigma presents itself which in all ages has agitated inquiring minds. How can it be that mathematics, being after all a product of human thought which is independent of experience, is so admirably appropriate to the objects of reality?” —Albert Einstein, in Geometry and Experience (1921).
On the relationship between mathematics and physics and the current state of affairs, see also: The Universe Speaks in Numbers: How Modern Maths Reveals Nature’s Deepest Secrets by science communicator Graham Farmelo (May 2019).
Since the 1970s … experiments at the world’s most powerful atom-smashers have offered few new clues. So some of the world’s leading physicists have looked to a different source of insight: modern mathematics. These physicists are sometimes accused of doing ‘fairy-tale physics’, unrelated to the real world. But in The Universe Speaks in Numbers, award-winning science writer and biographer Farmelo argues that the physics they are doing is based squarely on the well-established principles of quantum theory and relativity, and part of a tradition dating back to Isaac Newton.
 Physicist Jon Butterworth reviews Graham Farmelo’s book The Universe Speaks in Numbers in this Nature article “A struggle for the soul of theoretical physics” (16 April 2019).
The worry — expressed by a number of theorists and writers over several decades — is that theoretical physics has become a monoculture too focused on a small clutch of concepts and approaches. Those include string theory, overstated predictions of new discoveries, over-reliance on mathematical elegance as a guide and a general drift into what physicist and writer [science communicator] Jim Baggott, in Farewell to Reality (2013), called “fairytale physics” [multiverse, superstring theory, and supersymmetry*], divorced from its empirical base. Notable critiques have come from theoretical physicists including Peter Woit, Lee Smolin and, more recently, Sabine Hossenfelder … . Science writer Graham Farmelo clearly intends The Universe Speaks in Numbers as a riposte.
These [historical advances in physics] are brilliant successes of the mathematical approach, and Farmelo leads us through them adeptly, with a mixture of contemporary accounts and scientific insight. He also casts a sceptical eye on the stories the players tell about themselves — and here the tensions start to be felt.
During what Farmelo calls “the long divorce” between mathematics and theoretical physics from the 1930s to the 1970s, …* Wiki: [Baggott stated:] “When you start asking ‘Do we live in a hologram?’ Then you are crossing into metaphysics, and you are heading down the path of allowing all kinds of things that have no evidence to back it up, like creationism.” … He [Baggott] feels that empirical data provides an anchor for these people to “return to reality” and that science without evidence is “most dangerous.” … Science writer Philip Ball, in a review of Farewell in The Guardian, stated that Baggott was right “although his target is as much the way this science is marketed as what it contains.”
21 thoughts on “The future of (particle) physics?”
I found this Symmetry Magazine article (10/25/2018) interesting regarding particle research and the Standard Model: “Already beyond the Standard Model — We already know neutrinos break the mold of the Standard Model. The question is: By how much?”
The future of particle physics at Fermilab:
This U.S. Department of Energy podcast / article “S3 E7: DUNE: The Neutrinos Must Flow” (May 7, 2019) discusses the key role neutrinos play in the Standard Model regarding explaining why anything exists — why the symmetries of the Big Bang did not just result in matter and anti-matter annihilating, leaving nothing — as least no matter, only a “bath of energy.” This article contains some interesting pictures and [visualization] videos, as well as a transcript of the podcast. Over a 1000 scientists from around the world … a “megascience” experiment.
Fermilab: “Long-Baseline Neutrino Facility pre-excavation work is in full swing” (May 2, 2019).
Fermilab > Youtube: “Small Particles, Big Science: The International LBNF/DUNE Project” (March 28, 2016).
Department of Energy Announces $75 Million for High Energy Physics Research
LiveScience: “Physicists Search for Monstrous Higgs Particle. It Could Seal the Fate of the Universe” by Paul Sutter, Astrophysicist, June 5, 2019
This Interesting Engineering article “Fermilab is Still Alive After CERN – While it may no longer be the world’s premier atom smasher, interesting physics is still going on at Fermilab, and the neutrino might just be ready to give up its secrets” (June 23, 2019) is yet another look at ongoing research at Fermilab.
The article includes a YouTube video by Don Lincoln: “Everything you need to know about Fermilab” (published on Jan 22, 2019).
An interesting interview by Quanta Magazine of Carlo Rubbia, “an Italian particle physicist and inventor who shared the Nobel Prize in Physics in 1984 with Simon van der Meer for work leading to the discovery of the W and Z particles at CERN: “A Call for Courage as Physicists Confront Collider Dilemma” by Thomas Lewton, Contributing Writer (August 7, 2019).
– – –
The Quanta Magazine article also is referenced by Ethan Siegel, who discusses the pros and cons of current colliders in his Forbes article > “Forget About Electrons And Protons; The Unstable Muon Could Be The Future Of Particle Physics” by Ethan Siegel Contributor, Starts With A Bang Contributor Group (August 22, 2019).
But there are issues with muons, e.g., instability – “a mean lifetime of just 2.2 microseconds before decaying away.”
Fermilab also is involved in the hunt for dark matter.
Fermilab > Department of Energy awards Fermilab funding for next-generation dark matter research (October 18, 2019 | edited by Leah Hesla)
And here’s a (more recent) retrospective by Chad Orzel on his view of the future of particle physics:
Forbes > “What I Was Wrong About In Physics” by Chad Orzel Contributor (Sep 11, 2019)
• YouTube > PBS Space Time > “Can Future Colliders Break the Standard Model?” – Matt O’Dowd (August 24, 2020)
• Symmetry Magazine > “Defining the next decade of US particle physics” by Scott Hershberger (Oct 1, 2020) – The “Snowmass” process seeks to identify the most promising questions to explore in future research.
Re muons and the search for new physics … particle spin … magnetic moment … Feynman diagrams … QED, QCD … multi-photon (virtual) interactions (perturbative corrections) … W and Z bosons … gluons (self-interacting) … hadrons (particles bound by strong force) … (supercomputer) simulations vs. dispersion relation method …
• Symmetry Magazine > “The many paths of muon math” by Daniel Garisto (Oct 20, 2020) – Here’s how physicists calculate g-2, the value that will determine whether the muon is giving us a sign of new physics.
Re history of the Standard Model … the LHC … Higgs …
• Inverse > “By Coming Together, 3,000 Scientists Changed The Course Of Physics Forever” by Grace Browne (Oct 22, 2020) – “Without this collaboration, it would not have been discovered.”
Another perspective on the Muon g-2 experiment at Fermilab … precision mapping of the magnetic field is critical throughout the 45-meter circumference ring … to achieve field measurements accurate to 70 parts per billion … a trolley system [holding 17 probes] to drive measurement probes around the ring and collect data …
• Phys.org > “Scientists work to shed light on Standard Model of particle physics” by Savannah Mitchem, Argonne National Laboratory (Nov 5, 2020)
I’ve sometimes wondered about beam quality in particle accelerators. Wrangling clusters of trillions of particles at relativistic speeds.
It’s sort of like lasers, which I once imagined as purely monochromatic (coherent single frequency) light waves.
Beam loss is a major issue – “beam halos” which stray outside confinement fields and might touch the walls of the accelerator. It wastes energy (among other things), like in many devices where energy is lost to heat rather than primary output.
Phys.org > “After 20 years, physicists find a way to keep track of lost accelerator particles” by Jeremy Rumsey, Oak Ridge National Laboratory (February 23, 2021)
Maximum allowable density (for which beam halo is manageable)
Computer modeling simulation (for understanding beam loss patterns)
As a follow-up for some previous comments …
In anticipation of the first results from Fermilab’s Muon g-2 experiment, this article recaps the history of the muon’s magnetic moment. Spectroscopy … Dirac equation … empirically a tad extra magnetism … Schwinger’s virtual photons … looking for a slight additional wobble in the rotation of their spins … a muon decays into an electron and two neutrinos.
• Symmetry Magazine > “The mystery of the muon’s magnetism” by Brianna Barbu (03/30/2021) – A super-precise experiment at Fermilab is carefully analyzing every detail of the muon’s magnetic moment.
Presented by theoretical physicist Sean Carroll, this YouTube video, part of a series, is a useful historical overview of the The Large Hadron Collider, the largest machine ever built.
• YouTube > Wondrium > Sean Carroll > “The Large Hadron Collider” (Nov 5, 2021)
This Quantum Magazine article (below) reminded me that data from Big Science programs continues to be analyzed for years (perhaps decades) after being collected. In this case, much ado about the W boson.
• Quanta Magazine > “Newly Measured Particle Seems Heavy Enough to Break Known Physics” by Charlie Wood (April 7, 2022) – A new analysis of W bosons [using prior data] suggests [pending confirmation] these particles are significantly heavier [by 0.1%] than predicted by the Standard Model of particle physics.
This article includes a useful recap of the role of W and Z bosons in the so-called weak force.
• Beyond the Standard Model – sliver of reality?
“Ambulance-chasing” in physics? 
When an online news site publishes your opinion piece with a title you didn’t write (or see beforehand) …
• blogspot.com > Back Reaction > “I’ve said it all before but here we go again” by Sabine Hossenfelder – group think keeps grant cycles churning
A WAY FORWARD?
• The Guardian > Opinion > Particle physics > “No one in physics dares say so, but the race to invent new particles is pointless – Sabine Hossenfelder”
Credit: Pixabay/CC0 Public Domain with atomic decal added
Science is a human endeavor, and push back and skepticism can be helpful when inspiring positive change. Yes, unbridled curiosity can go off the rails in the wider scheme of priorities. But “broad brush” claims can thwart communicating science.
So, Jackson Ryan makes a case for pushing particle physics forward – in the context of “questions worth asking, conversations worth having.”
• Cnet > “Are Particle Physicists Wasting Time Inventing New Particles? No, but It’s Complicated” by Jackson Ryan (Oct 3, 2022) – Sabine Hossenfelder’s commentary about the “doldrums” in particle physics is not “blowing the whistle” on something secret.
A thing regarding the completness of the Standard Model: lepton flavor universality.
• Wiki > Lepton flavour universality
This article contains some useful diagrams on the Standard Model.
• Scientific American > “Rule-Breaking Particles Pop Up in Experiments around the World” by Andreas Crivellin [theoretical physicist, University of Zurich and the Paul Scherrer Institute in Switzerland] (November 1, 2022)
Andreas Crivellin chronicles his research regarding whether there are forces that discriminate among lepton generations.
He then summarizes “four different indications that lepton flavor universality might not hold true.” Measurements of certain particle decay processes: two involving quarks and leptons, and beta decay. And LHC collisions of two protons – “more electrons were produced in comparison to muons than expected.”
At points, there’s speculation that virtual particle interactions might explain departures from decay predictions.
However, “some of the most intriguiing signs that particles are breaking the rules of physics are measurments of muons …” – Fermilab’s G-2 experiment.
Enter leptoquarks! Or, heavy fermions. New models. And future particle accelerators.
The article’s illustrations help mere mortals follow his detective story. Here’s one example.
(image link) The Standard Model by Jen Christiansen
Image credit: Jen Christiansen, Senior Graphics Editor, Scientific American
This article is a big-think recap (you may encounter a subscription paywall).
Visions of Grand Unified Theories (GUTs)? Is there a future for string theory?
• New York Times > “Where is Physics Headed (and How Soon Do We Get There)?” by Dennis Overbye (January 25, 2023) – Two leading scientists discuss the future of their field.
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