[HN Gopher] A muon collider could revolutionize particle physics...
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A muon collider could revolutionize particle physics, if it can be
built
Author : rbanffy
Score : 64 points
Date : 2024-03-29 18:18 UTC (4 hours ago)
(HTM) web link (www.science.org)
(TXT) w3m dump (www.science.org)
| PaulHoule wrote:
| One interesting thing about muon accelerators is that they could
| produce enough neutrinos to be dangerous:
|
| https://accelconf.web.cern.ch/p99/PAPERS/WEBR6.PDF
|
| which might be a good thing in that the neutrino mass is a
| "missing part of the standard model" as opposed to "possible
| physics beyond the standard model". The neutrino mass term could
| explain dark matter, dark energy and the matter-antimatter
| asymmetry
|
| https://arxiv.org/abs/1303.6912
|
| whereas a Higgs Factory or top factory seems likely to be a big
| disappointment because all the evidence we have is that the Higgs
| field is as simple as it could possibly be and a top factory
| might end up just verifying that complex calculations people did
| 40 years ago (by the time the machine comes up) were right.
|
| Muon colliders are a possible path to a Higgs factory or top
| factory but the path to a muon accelerator that can revolutionize
| precise neutrino physics is much shorter and I think more
| rewarding.
|
| Notably neutrino physics is win-win. Either the right-handed
| neutrino exists as a heavy particle and is very likely to be the
| darkon or the neutrino is a Majorana fermion (is its own
| antiparticle) which is certainly a weird and interesting result.
| Contrast that to all the other poorly motivated darkon candidates
| such as sparticles, axions, etc.
|
| I remember reading a lot of papers about muon accelerators about
| 20 years ago, they have been a big research topic in the US and
| Japan because we didn't have CERN.
| rbanffy wrote:
| > enough neutrinos to be dangerous
|
| That would have to be a huge amount of these little things.
| PaulHoule wrote:
| ... and higher energy so that they have a higher interaction
| cross section
|
| https://arxiv.org/pdf/1305.7513.pdf
| science4sail wrote:
| > they could produce enough neutrinos to be dangerous
|
| Dangerous in the sense of "ionizing radiation" or in the sense
| of "this will overturn careers"? Getting killed by neutrinos
| sounds like a freak accident from a sci-fi story.
| PaulHoule wrote:
| Read the paper. You could get a dangerous dose if you were
| near the plane of the accelerator.
| LegitShady wrote:
| "near" is a relative term that isn't specific enough to get
| an idea of how dangerous something is.
|
| It's dangerous to be near hydrogen sulfide. It's dangerous
| to be near a primed hand grenade. It's dangerous to be near
| an artillery shell impact. It's dangerous to be near a
| drunk driver. It's dangerous to be near an active
| battlefield or even near a war.
|
| But they are all different nears.
|
| When you say its dangerous to be near the plane of the
| collision, are we talking 1m, 10m, 100m, 1000m, etc? Are
| there dangerous byproducts created that might kill you even
| after the event itself? That's useful information. A
| general "don't be near" isn't really helpful.
| __MatrixMan__ wrote:
| From the paper:
|
| > Most of the ionization energy dose deposited in a person
| will come from interactions in the soil and other objects in
| the person's vicinity rather than from the more direct
| process of neutrinos interacting inside a person. At TeV
| energy scales, much less than one percent of the energy flux
| from the daughters of such interactions will be absorbed in
| the relatively small amount of matter contained in a person,
| with the rest passing beyond the person.
|
| If you're looking to get bit by a radioactive spider, spiders
| living down range of such a collider might be a decent place
| to start.
| PaulHoule wrote:
| With high-energy particles the showers made when the
| particles hit something can be more dangerous than the
| original particles.
|
| For instance if you are building a space colony there is an
| optimal thickness for the biological shield: most high
| energy particles blast right through you and if you have
| too much shielding there are too many opportunities for a
| particle to explode a nucleus in the shield and multiply
| the number of radioactive particles dramatically. Off the
| top of the head I'd say about six feet of soil is about
| right, but you don't do better with 60 feet or anything
| reasonable until you are talking multiple kilometers (maybe
| of vacuum or air space) that give shower muons time to
| decay.
|
| Speaking of muons, it is an easy experiment often used in
| physics education to measure the the lifetime of cosmic ray
| muons produced in showers.
|
| https://www.physlab.org/wp-
| content/uploads/2016/04/Muon_cali...
|
| If a muon gets slowed down by matter you see a pulse of
| radiation, then you see a pulse of radiation a few
| microseconds later when the particle decays. If you measure
| the time gap in two-pulse events you can get the half-life.
| It was a popular experiment in Cornell's 510 lab for grad
| students who weren't particularly interested in doing
| experiments because it was so easy.
| Cthulhu_ wrote:
| Doctor Manhattan
| zem wrote:
| wow, i would not have imagined you could possibly produce a
| dangerous dose of _neutrinos_! the numbers involved must be
| extremely high.
| gattr wrote:
| Related XKCD: "How close would you have to be to a supernova
| to get a lethal dose of neutrino radiation?"
|
| https://what-if.xkcd.com/73/
| pfdietz wrote:
| Note that these neutrinos (from the collider) have much
| higher energy than those from a supernova.
| pfdietz wrote:
| It's not their number so much as their energy. The cross
| section for energetic neutrinos interacting with matter
| scales as energy squared, if I recall correctly. These
| neutrinos have cross sections too low to shield, but too high
| to ignore.
| amelius wrote:
| Yes, but I'm guessing you still can't blast someone on the
| opposite side of Earth with a stream of neutrinos going right
| through the core.
| _qua wrote:
| This is fascinating. Never would have thought neutrinos could
| be a problem!
| edwcross wrote:
| There was a discussion two months ago
| (https://news.ycombinator.com/item?id=39271472) about a paper
| on using neutrino beams to destroy nuclear weapons, which
| showed that neutrinos can be dangerous.
| Zardoz84 wrote:
| > they could produce enough neutrinos to be dangerous
|
| I find hard to believe that we can produce more neutrinos that
| the sun produces.
| ithkuil wrote:
| Doesn't the beam intensity decrease with the square of the
| distance?
| jiggawatts wrote:
| My initial gut reaction was that the authors were ignoring the
| obvious solution of simply putting the ring below ground level
| and setting up maintenance walkways above the ring instead of
| next to it.
|
| Then I realised the the Earth is spherical and that it doesn't
| matter how deep you put this thing, the beam will come out
| _somewhere_ , even if it needs to go through a thousand
| kilometres of regolith to get there.
|
| So there could be some random patch of grazing land somewhere
| in another country that's dangerous to go near whenever the
| experiment is running.
|
| PS: I solved the funding problem! Just tell the military about
| this new unstoppable death ray that can kill anyone even
| through the planet. [Disclaimer: death will be a decade from
| now due to cancer. Victim must remain stationary for one year.
| Construction work is required to retarget beam.]
| f6v wrote:
| I'm doing a PhD in quantitative field, not stupid by any means.
| But people doing physics seem out of this world to me. I feel
| like they're just orders of magnitude smarter. It's a shame the
| field seems a bit stagnant now. I hope they find a way to advance
| the knowledge without planet-scale accelerators. There should be
| a feasible and elegant compact solution.
| whatever1 wrote:
| They do have insane pattern recognition skills when it comes to
| models. Good mathematicians also have this.
|
| But the good ones are very hard working too, in order to build
| a big enough library of building blocks.
| Jensson wrote:
| > They do have insane pattern recognition skills when it
| comes to models. Good mathematicians also have this.
|
| The skills physicists and mathematicians build aren't very
| comparable.
|
| Physicists has the more complex equations and models,
| probably most complex of any field since physicists often
| invent new math to model things. Quantum field theory is
| insanely complicated math wise with infinite number of
| infinite integrals, mathematicians has still not figured out
| how to formalize that.
|
| Mathematicians focuses much less on modeling and equations so
| they aren't as good at that, instead they are much better at
| formal proofs and theorems. The skills are very different and
| doesn't translate well.
|
| Or in other words, physicists are experts at making complex
| math tools to model things. Mathematicians are experts at
| verifying tools that exists. Those two skills has less
| overlap than you might think.
| vcxy wrote:
| Interesting way to look at it. Your description of what
| physicists are experts at matches my math PhD pretty
| closely. I focused on mathematical modeling. I now work
| with a bunch of physicists, so I guess that checks out.
| Jensson wrote:
| Yeah, if you work on the applied side of math it can be
| very similar to what people do in physics. But I was
| thinking more about pure math.
|
| Edit: I think the main difference there is that in
| applied math they still prove that the models are
| mathematically correct. In physics they just show that
| the model align with experiments and skip math formalism.
| vcxy wrote:
| Yeah, that seems true and it's basically the value
| proposition I bring to my work.
| lokimedes wrote:
| I was with you on the generalities, but oh do theoretical
| physics suffer from math envy when it comes to formalism.
| Basically since the invention of quantum mechanics, has
| physics been dominated by "proofs" and "theorems" like
| the physical world is assumed to be axiomatically defined
| by Heisenberg's and Pauli's principles, and everything
| else is just maths. No small part of the stagnation I
| sense in physics today stems from too deep a faith in the
| ultimate truth of the mathematical models we call
| theories. It doesn't help the fact that we rely on Taylor
| expansions and perturbation methods for most experimental
| predictions. The Higgs hunt and the passivity of the
| (experimental) physicists in challenging this stupid
| theory-driven search for new physics is emblematic of
| this era. If only math was seen as a modeling language
| and not somehow truth/consistency itself, physics would
| be much better off.
|
| (Disgruntled particle physicist, declaring colors)
| Jensson wrote:
| Yeah, I saw that as well, met some professors in grad
| school that started talking about physics in terms of
| axioms and proofs instead of experimental results and
| models. At that point I lost interest and just went with
| math instead, if it is going to be math anyway why not go
| with the real thing.
| pinko wrote:
| not all physics is particle physics! gravitational-wave
| physics, for just one example, is not the least bit stagnant!
| and soft matter physics is amazingly fertile ground right
| now...
| wholinator2 wrote:
| Yes, there's quantum computers and information with
| fundamental tests of quantum mechanics, condensed matter with
| superconductors, soft Condensed matter in Biophysics with dna
| and protein folding, computational physics that underpins
| huge swaths of theoretical chemistry. There's many many other
| fields of physics, each with dozens of exciting projects
| going on right now.
|
| Particle physics/cosmology is closest in some sense to
| "fundamental physics". Its also, as i understand, the most
| competitive field in physics right now with the highest
| achieving theoretical mathematician people (i.e. the super
| geniuses) but that's also an effect of the slowly drying
| funding making the field more selective. It's by no means the
| only field in physics and there are extremely intelligent and
| hard working people in all fields of physics doing high
| impact, world changing research because they love it.
| drowsspa wrote:
| I did a Master's in Condensed Matter Physics and I still agree
| with you. (edit: obviously I'm not including myself there)
| pinko wrote:
| I will also add, as an academic who works closely with hundreds
| of physicists, that although they are indeed typically smarter
| in one dimension, they are also _considerably_ dumber than your
| average person in others. It turns out life is all about
| tradeoffs!
| whamlastxmas wrote:
| My partner with a PhD in particle physics says this all the
| time about herself
| dylan604 wrote:
| TFA: The P5 report calls for R&D on a muon collider, stating,
| "This is our muon shot."
|
| That just doesn't have the same ring to it as "moon shot". I hope
| they do not continue using this phrase. It doesn't have the same
| gravitas nor is it awe inspiring. I highly doubt it help earn
| funding. In fact, it leaves me with a negative charge.
| jjtheblunt wrote:
| It's just physicists and their quarky humor.
| Sharlin wrote:
| > It doesn't have the same gravitas
|
| This just in: Physicists now refer to the proposed muon
| collider project as their "Sorry, We're Fresh Out Of Gravitas"
| shot.
| kjs3 wrote:
| "Sorry, We're Fresh Out Of Gravitas" is going to be the GSV
| name in my Ian Banks Culture fanfic.
| ok_dad wrote:
| People should have more fun while doing important work. Being
| too serious when on the cutting edge leads to an overinflated
| ego.
| lapetitejort wrote:
| I'm neutrino on the phrase
| bashinator wrote:
| I think if you can find a way to reconcile gravitas with
| quantum field theory, you're in for several igNobel prizes.
| bell-cot wrote:
| You know you've read too much SF when...your first reaction to
| the title is "A time machine could revolutionize physics, if it
| can be built".
| rbanffy wrote:
| Well... It could.
| perihelions wrote:
| - _" Decaying muons also radiate energetic neutrinos, creating a
| novel radiation safety challenge. Shooting horizontally from the
| collider ring, these elusive particles would zip through the
| earth and emerge dozens of kilometers away."_
|
| I understand you have neutrinos leaking from the entire collider
| ring, along all the tangent rays? That fills out an entire
| geometric plane!
| delichon wrote:
| Maybe the collider is the basis of a neutrino transmitter.
| The purpose of this study was to inspect the possibility of
| using neutrinos for communications for military submarines ...
| Because neutrinos are nearly unaffected by matter, a neutrino
| beam could traverse directly through the earth from the
| transmission site to the submarine. A directional beam would
| allow confidential information to be passed only to the
| intended recipient. Neutrino communications would also be
| totally jam-proof. As an additional benefit, a neutrino message
| could be received in the deepest of waters, leaving a submarine
| less vulnerable to enemy attacks. -- https://www.physics.ucla.e
| du/~hauser/neutrino_communication_paper/siljah_mod.htm
|
| But the conclusion isn't optimistic about the receiver.
| PaulHoule wrote:
| Already people do experiments where they shoot a proton beam
| at a target and then detect the resulting neutrino beam at a
| far distance, for instance
|
| https://www.dunescience.org/
|
| and
|
| https://en.wikipedia.org/wiki/2011_OPERA_faster-than-
| light_n...
|
| A muon storage ring with straight sections would produce
| powerful beams in the direction of the straight sections when
| the muons decay which would produce orders of magnitude
| higher flux than existing accelerator neutrino experiments
| not to mention a highly collimated beam.
|
| (I am still amused by the superluminal neutrino flap because
| (a) it wasn't the first case where people thought they saw
| superluminal neutrinos, I remember seeing an experiment at
| Los Alamos Lab where curve fitting the neutrino mass was
| giving an imaginary (superluminal) number in the 1990s, and
| (b) it sounds so much like something out of
| https://en.wikipedia.org/wiki/Steins;Gate)
|
| The OPERA experiment does show that if your equipment was
| calibrated properly you could possibly get a high data rate
| from turning your source on and off rapidly, however, I don't
| think you can turn a muon storage ring on and off.
| perihelions wrote:
| - _" however, I don't think you can turn a muon storage
| ring on and off."_
|
| What if you had two storage rings whose straight sections
| were at slightly different angles, and a switch bridging
| them? Populate one ring for "on", move muons to the
| alternate ring for "off".
| wholinator2 wrote:
| I have a question. Doesn't observing some signal require
| interacting with it? And wouldn't most interaction sufficient
| to gain a high fidelity signal modify the underlying
| particles in some way that might destroy the message? How, if
| we can retrieve the message in the beam with accuracy, do we
| not simultaneously gain the technology to disrupt the beam?
| Isn't jamming just loud and sophisticated form of
| communication? If we can communicate, how are we not
| simultaneously able to jam?
| ars wrote:
| Neutrinos are directional. Any jamming would come from a
| different direction.
|
| The jammer can't match the direction - as the submarine
| moves the direction of the source changes in a predictable
| way, the jammer would change in a different way.
|
| Think of it as a tiny light bulb blinking as you walk in a
| circle around it. Doesn't matter where you put the jamming
| light bulb it won't be in the center of your circle like
| the source light bulb is.
| karol wrote:
| I'll try without it.
| m0llusk wrote:
| It might be worth considering just how much other physics could
| be done with these resources. Improve education and
| experimentation for many other investigations instead. There is
| still much to learn about fluid dynamics, the chemistry of water,
| alternative plastics, and many other open questions. The vast
| amounts of resources poured into exotic reactors could educate
| many more physicists, launch many more satellites, and operate
| many more laboratories. Moving forward with very large projects
| may effectively starve out other investigations that might
| ultimately have far more practical applications. In some ways
| this proposal seems more like a lack of imagination than a
| positive surplus of imagination.
| bigbillheck wrote:
| That's all true, but they wouldn't spend the money on those
| kinds of things, they'd just buy more fighter jets.
| PaulHoule wrote:
| I'd say that the "missing" neutrino mass term and the identity
| of the dark matter particle (quite likely a neutrino) are two
| of the most interesting problems in physics and I'm afraid that
| Team LHC's interest in (I think boring) Higgs and Top factories
| could crowd out investment in the much more interesting area of
| neutrino physics the way that you say.
|
| The good news is that going down the muon accelerator route you
| probably need to build a neutrino factory to validate the
| technology long before you can build those other things.
| rrix2 wrote:
| just one more accelerator bro. just one slightly larger
| accelerator than the one we just got online. we can revolutinize
| physics with just one more accelerator bro
| ceejayoz wrote:
| The article is about a much _smaller_ accelerator.
|
| > A muon collider could be much smaller and cheaper than a
| functionally equivalent proton collider, advocates say. It
| could fit on the 2750-hectare campus of the United States's
| dedicated particle physics lab, Fermi National Accelerator
| Laboratory (Fermilab), enabling the U.S. to reclaim the lead in
| the continuing competition for the highest energy collider.
| Most important, younger physicists say, it might be built
| sooner than a more conventional competitor, perhaps in as few
| as 25 years. "If you want you can add 10 years to that, that's
| still a lot better than when I'm dead," Holmes says.
| rrix2 wrote:
| :) When I made the joke I was thinking about energy levels
| and theoretical physicists'/string theorists insistence that
| we're just a bit more energy away from evidence of the grand
| unified theory
| coldtea wrote:
| Wasn't that what was said for the LHC?
| vouaobrasil wrote:
| I feel like this sort of research cannot be good in either
| direction: it seems like a waste of money and resources for
| society to fund this and other abstract things which can only
| lead to amusing mathematical models that will have zero impact on
| society, which is a bad thing because we have very real problems.
| But, if it DOES lead anywhere, the technology could be
| devastating and we're probably too stupid to use it. Seems
| pointless to me.
| jstummbillig wrote:
| That's one too many conditionals in the title to not be a little
| suspicious. Exciting, still.
| casey2 wrote:
| Building more colliders isn't what I would call a revolution,
| more like status quo. What would be a revolution is if a series
| of scientifically sound (tabletop) experiments started advancing
| the field.
| parhamn wrote:
| > if a series of scientifically sound (tabletop) experiments
|
| Does fruit hanging this low still exist?
| floxy wrote:
| https://news.stanford.edu/2019/09/25/precision-physics-
| table...
|
| https://phys.org/news/2014-12-world-compact-tabletop-
| particl...
| peterfirefly wrote:
| For a sufficiently long table:
|
| https://en.wikipedia.org/wiki/AWAKE
|
| https://en.wikipedia.org/wiki/Plasma_acceleration
|
| Nobody knows if wakefield accelerators will be good enough
| but they are improving fast and they aren't too expensive to
| build.
| ndngmfksk wrote:
| If such tabletop experiments were possible, then surely the
| particle physicists who use these colliders would be building
| them? As far as I can see, they're requesting colliders because
| to the best of their knowledge, colliders are necessary.
|
| A muon collider would be revolutionary in the sense that it
| would open up a new energy range for lepton collisions. It
| would also be a technological marvel.
| nlavezzo wrote:
| This is very cool.
|
| That said, it reminded me of a funny collider meme I saw
| recently:
|
| https://tinyurl.com/2k8u4dk6
| UberFly wrote:
| 22 billion would be a bargain bro :)
| manojlds wrote:
| The Trisolarans won't allow us to.
| sp332 wrote:
| The LHC has been doing lead-lead collisions (occasionally) for a
| few years now. How much more energetic would this smaller muon
| reactor be?
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