A muon collider could revolutionize particle physics, if it can be built
science.org
science.org
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.
That would have to be a huge amount of these little things.
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.
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.
As far as the danger, the paper estimates up to a few mSv/year if you hung out in the wrong place all the time. You definitely wouldn't want to have a town in the way of that, but it's not an immediate danger on an individual level. The danger would be greater/more concentrated if there were straight segments in the accelerator, or if it was closer to the surface (smaller circle of intersection).
What wad said was so vague as to be practically useless.
"...they give examples of accelerators buried at 300 meters which would create a radiation hazard at a radius of 62 kilometers"
Again, this is overly vague and unhelpful. As I replied to LegitShady, no specific mention is made about the type of radiation dangers or how long radiation would be expected to linger in soils etc.
More specific estimates of safe distances versus collider power would be helpful, same too about the nature and type of radioactive byproducts in soil (what elements would be expected to become radioactive along with their half-lifes, etc.).
Sometimes I think it ought to compulsory for scientists to study philosophy—at least its parts that deal with logic, language and semantics.
Philosophy defines near —like good— as a 'simple notion' that cannot be subdivided into simpler terms. The word needs qualifiers/quantifiers (figures, distances, amounts) for it to be useful—info that the paper was overly vague about or omitted to specify.
> 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.
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.
In theory hitting nukes with energetic neutrino ray would be enough to disarm them. By melting fissile material under normal circumstances.
I find hard to believe that we can produce more neutrinos that the sun produces.
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.]
If you mount two of them like a gyroscope, inside a spherical opening, the planes could overlap into a target-able beam.
https://arxiv.org/abs/physics/9908017 ("Potential Hazards from Neutrino Radiation at Muon Colliders")
But the good ones are very hard working too, in order to build a big enough library of building blocks.
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.
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.
(Disgruntled particle physicist, declaring colors)
This isn't really the case. In general in any class of mathematical objects, the physically realizable ones are the most tame. Physical realizability is a huge constraint that typically dramatically simplifies problems.
> Quantum field theory is insanely complicated math wise with infinite number of infinite integrals, mathematicians has still not figured out how to formalize that.
My understanding was that the issue is that QFT as used by physicists is known to be mathematically inconsistent. For example, see Haag's theorem [0]. As Wikipedia puts it "there does not exist a well-defined interaction picture for QFT, which implies that perturbation theory of QFT, which underlies the entire Feynman diagram method, is fundamentally ill-defined."
So the problem is not that we don't know how to formalize it, it's that what physicists are doing is known to be wrong. So we need some better argument for why it sometimes seems to work under the conditions it does. And that's arguably more about getting the physics right than it is about math.
This is something that happens in general: physicists will often use tools or arguments that are known not to be correct despite the fact that they work well in practice.
I think in general, that's a good thing. Physicists need to be able to brainstorm ideas in a way that is unconstrained by needing to formally prove them. In this process they might find something that works 60% of the time. Then someone will refine it to work 80% of the time, etc. But at the end of the day, the tools do have to be mathematically consistent for them to actually describe the physics, unless we live in a mathematically inconsistent universe.
So the characterization I'd give is that physicists are generally better at modeling, but also less constrained by the need to be correct.
> Mathematicians are experts at verifying tools that exists. Those two skills has less overlap than you might think.
This part is reversed IMO. Mathematicians created nearly every major tool used by physics since the history of humanity. Occasionally physicists will run ahead and come up with an idea that is lacking in tools, and they'll turn to mathematicians as the tool experts for help. Like, for example, Einstein did when trying to formulate relativity. More rarely, they'll come up with a novel tool like Feynman diagrams without knowing why they work, and then the mathematicians will be called in as the experts to sort things out.
And of course it is true that physicists will come up with ideas like the Ads/CFT correspondence that arise from physical considerations. It's also true that the problems of physics can inspire new mathematics simply because they're new and interesting problems.
Calculus was created by a physicist who didn't even bother it since he just published the resulting physics, Fourier analysis was created by a physicist etc. Mathematicians first and foremost formalizes things after they were created, they don't create many useful tools to begin with. Very few fundamental tools were made first by mathematicians.
They often call physicists/polymaths mathematicians after it happened since they published a lot of math, but they did the physics/natural first at the time. The formalist mathematicians we see today weren't even a thing 150 years ago, the useful tools developed by formalist mathematicians is basically zero, the new useful tools physics used the past 100 years were done by themselves.
For example, generalized functions where done by physicists, mathematicians scoffed at it saying it is inconsistent as you said here, but then after over 100 years apparently it all worked out just and the physicists were right that you can work with functions that are defined by their properties when integrated instead of their values. The same will happen to QFT, it isn't wrong to work with infinities its just that mathematicians aren't good enough to figure out how to formalize such tools but such tools working with infinities works.
I have studied both theoretical physics and pure mathematics at a graduate level and published in both, I have a fair idea how the fields works. Rarely formalizing a tool can open up for more usages of it, but that is about it.
Calculus was discovered by a number of people. I'm assuming you're thinking of Newton, who was a professor of mathematics and whose advisor was a mathematician. Remember the fundamental theorem of calculus had been proven by mathematicians Gregory and Barrow (Newton's advisor) before Newton, not to mention the work of people like Fibonacci. Calculus as we know it today was mainly developed by the mathematician Leibniz independently of Newton.
> Fourier analysis was created by a physicist etc
Joseph Fourier was a mathematician whose advisor was mathematician Joseph-Louis Lagrange whom he succeeded at ENS.
> Mathematicians first and foremost formalizes things after they were created, they don't create many useful tools to begin with. Very few fundamental tools were made first by mathematicians.
This is wildly wrong and contrary to history.
> They often call physicists/polymaths mathematicians after it happened since they published a lot of math
The people I'm calling mathematicians, like Newton and Fourier, are people who trained in mathematics and had mathematical advisors. What other definition do you want of a mathematician other than one who does math, studied math, is employed to do and teach math, and whose advisor was a mathematician?
For example, while Wikipedia calls Fourier a mathematician and physicist, Britannica just calls him a mathematician. Britannica does mention that he was also an Egyptologist but never calls him a physicist.
> generalized functions where done by physicists
Distributions have been used by mathematicians since the 19th century. I'm aware of no examples of physicists claiming priority. Physicists do often use them incorrectly, for example a lot of physicists view the Dirac delta "function" as a function despite the fact that no functions have those properties. They sometimes confuse that, as you seem to do, with thinking that mathematicians don't understand what generalized functions are about.
Douglas adams solved it though, he understands why this flawed physics seems to work -- 6x9 = 42
Your point stands though: mathematicians are indeed able to cope with path integrals. But several of the models -- qed, Higgs, electroweak, basically everything but qcd -- used in particle theory suffer from a fatal flaw, the Landau pole. They can only exist as incomplete approximations to something else.
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.
With intensity going past LHC is looking very difficult but not necessarily impossible. There's been advances in compact linear accelerators that look promising.
With sensitivity we're got a lot of untapped potential to observe high energy particles/physics produced by nature.
I don't mean to trivialize the difficulties but there's reasons to be optimistic about us learning new physics in the coming decades.
That said, it reminded me of a funny collider meme I saw recently:
Does fruit hanging this low still exist?
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.
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.
I agree that muon colliders are a better investment than something like the Future Circular Collider though, it's an area that hasn't been as thoroughly explored.
Energy scales for new physics can be enormous for all we know, I do not see any reason to expect that new physics hides "around the corner" (in a 1.5 orders of magnitude FCC or muon collider could give us). Muon collider is at least looking in a different place, and it's definitely more interesting than FCC for me, but I'm still not 100% sure it is the right thing to do, given the limited resources.
I understand you have neutrinos leaking from the entire collider ring, along all the tangent rays? That fills out an entire geometric plane!
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.edu/~hauser/neutrino_communication_paper/siljah_mod.htm
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.
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".
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.
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.
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.
This just in: Physicists now refer to the proposed muon collider project as their "Sorry, We're Fresh Out Of Gravitas" shot.
So when the posted article says,
muons are fundamental particles that put all their energy into a collision, enabling a muon collider to compete with a hadron collider running at 10 times the energy. So the muon collider could be much smaller and, hence, cheaper. A 10-TeV muon collider could be had for $18 billion, advocates estimate.
it actually understates the case for a muon collider. It is not just more efficient, it's also cleaner, since muons, like electrons, don't do strong interactions.
> 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.
Also we haven't built a collider that's even close to the collision energies of the SSC, which was cancelled mid-construction over 30 years ago. We're still playing catch-up.