They're probably interesting to study on their own, but the engineering instinct is to want to build something out of them, or use them as tools, which seems pretty hard if they disintegrate in a quintillionth of a second!
If a particle can decay into a lighter set of particles and still obey all of the conservation principles, they will. The heavier they are, the more they're going to decay and the more "options" they have to decay. An electron isn't going to do anything because there is nothing lighter than an electron that still carries charge, etc. Something much heavier, like a free neutron, will fall apart into a proton, an electron, and an anti-electron neutrino.
These particles have options galore as to what they can fall apart into being, and so they do, and with great haste.
For the sake of my own edification, I'd like to follow this up with a few somewhat seemingly dumb questions if you dont mind:
Is it the case that a given particle is trying to settle into a "lowest energy state" possible? I am not using physics terms here. More like conceptually, are these particles, due to the number of options available to them, decaying into the lightest stable variant allowed by the laws of physics? if that is the case, then could we perhaps find ways to engineer structures within which these particles last for a whole lot longer than they should (on a human timescale)? And what is stopping us from doing that? is it the energy cost associated with such a structure/device or is there a more fundamental reason we cant do that?
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>>trying to settle into a "lowest energy state" possible?
What if its actually the reverse: Its attempting and succeeding to be the most it can be given the eddy of forces around it - the particle is "becoming" - not "falling apart"
> Is it the case that a given particle is trying to settle into a "lowest energy state" possible?
Not exactly. Energy is conserved during these decays. In fact, energy is conserved during all physical processes, so the "lowest energy state possible" is a little bit of a white lie. What makes it a white lie is that it is a very good approximation to the truth for thermodynamic systems, i.e. systems consisting of large numbers of particles. But for quantum systems, it is no longer a good approximation. In quantum systems, what happens is that you have a wave function that describes all of the possible states a system can be in. The more mass the system contains, the more possible states there are in its wave function, and so the more likely it is to end up in some state other than the one it started out in.
It is even possible for the process of decay to reverse itself, and for the constituent particles to come back together and reconstruct the original, but for that to happen all the constituents have to be brought back together, so as a practical matter this never happens spontaneously in nature. In fact, that is the whole reason for building the LHC -- to make particles (protons) come together and make high-mass systems which then decay in interesting ways.
> are these particles, due to the number of options available to them, decaying into the lightest stable variant allowed by the laws of physics?
Not the lightest stable variant, just to one of the possibilities described by that particle's wave function. These will always be subject to the constraints of conservation laws, so the decay products will always be lighter than the original. But which particular set of possible decay products is actually produced in any given decay event is fundamentally random.
> if that is the case, then could we perhaps find ways to engineer structures within which these particles last for a whole lot longer than they should (on a human timescale)?
No. The wave functions for particles are fixed by nature. They are what give particles their identities. They cannot be engineered. The only thing that we can engineer is the arrangement of particles. Particles are like Lego bricks. You can stick them together in lots of different ways, but you can't change the shape of a given brick. Sometimes quantum Lego bricks fall apart spontaneously, but there is no way to control that.
(Wouldn’t this be example of a structure that prevents decaying?)
Be careful to remember your conservation of baryon number when listing your options!
Both fusion and fission release energy when they occur. Which seems somewhat weird to me. Is it the cases that the reason a stable atom has less energy than the sum of its parts (as you pointed out) is because it gave off some energy during the fusion process?
That is correct. "Particle" is another one of those "white lies."
Sometimes they will have intermediates, which then decay, and then those products decay, and so on. That's quite common. Eventually they just ... fall apart. The more options, the faster. The greater the energy stepdown, the faster, by which I mean "can it release a gamma? Or fall apart into some much smaller things?"
However, it is independent of "nearby" structure, where nearby is any distance larger than the nucleus. So, no, we cannot contain these particles within anything to prevent their decay, it is like trying to build a bouncy castle around a hand grenade in hopes that it won't go off.
Note that there is an apparent delay in decay, from our perspective, when particles are moving very fast, like a relativistic muon lasting longer (although still a very brief period of time by our standards) than expected, simply due to special relativity. But here this also would not help.
Things fall apart, the center cannot hold, and so on.
That puts it in perspective. Thanks for the reply and for taking the time!
Most Particles Decay — But Why?
https://profmattstrassler.com/articles-and-posts/particle-ph...
Most Particles Decay — Yet Some Don’t!
https://profmattstrassler.com/articles-and-posts/particle-ph...
Neutron Stability in Atomic Nuclei
https://profmattstrassler.com/articles-and-posts/particle-ph...
It's more accurate to think of the energy "spreading out" (remember that mass is a form of energy too, since E=mc^2). The energy can rearrange (subject to conservation laws), between being one massive particle, or several lighter ones (in fact there's a superposition of possibilities, because quantum).
In principle the probability of switching back-and-forth is equal, e.g. the probability of particle A decaying into a B+C pair, is identical to the probability of a B+C collision producing an A. However, most of the directions those light particles can take will result in them flying apart rather than colliding; that spreads out the energy, so it can no longer switch back into the massive particle configuration.
Note that this is essentially the first and second laws of thermodynamics (energy is conserved, and concentrations tend to "spread out" over time)
Some of the heavy elements assembled in colliders are described as decaying so quickly that one side of the nucleus is coming together even as the other side is disintegrating, a sort of brief wave of existence traveling at nearly the speed of light across this thing that has been forced together and wants to fly apart.
(Or at least, that's the magnitude of a Higgs boson decay, about 160 yoctoseconds.)
To save some googling: about 10^-22 seconds for a Higgs boson decay. Whe a nanosecond, one tick in a 1GHz clock, is 10^-9 seconds.
Also note that they're not rare and there's a fair bit of neat science behind that too.
> About 10,000 muons reach every square meter of the earth's surface a minute
(from https://www.scientificamerican.com/article/muons-for-peace/ ).
There's also neat stuff with time dilation and muons ( http://hyperphysics.phy-astr.gsu.edu/hbase/Relativ/muon.html ) - there should be far fewer observed muons at the surface if muons didn't experience time dilation from their relativistic speeds.
> The historical experiment upon which the model muon experiment is based was performed by Rossi and Hall in 1941. They measured the flux of muons at a location on Mt Washington in New Hampshire at about 2000 m altitude and also at the base of the mountain. They found the ratio of the muon flux was 1.4, whereas the ratio should have been about 22 even if the muons were traveling at the speed of light, using the muon half-life of 1.56 microseconds. When the time dilation relationship was applied, the result could be explained if the muons were traveling at 0.994 c.
(note: mean lifetime and half-life are different numbers)
The thing here is that 2.2 μs is slow, but even with something that is that fast (on a human scale), there's a lot of neat science that can be done with them. They've even made muonic atoms (where the electron is replaced by a muon) https://en.wikipedia.org/wiki/Exotic_atom ... and that leads to possibilities on lowering fusion temperature ( https://en.wikipedia.org/wiki/Muon-catalyzed_fusion ) because the muon is much closer to the nucleus in its ground state.
Lone neutrons are unstable, they decay in about 15 minutes to lighter particles. They have only a few MeV mass difference to the stable final state (the proton + electron + anti-neutrino).
For comparison, these particles are 2000+ MeV above their ground states so they decay pretty quickly.
(It might not even exist, after all…)
> There exists no formal definition of a WIMP, but broadly, a WIMP is a new elementary particle which interacts via gravity and any other force (or forces), potentially not part of the Standard Model itself, which is as weak as or weaker than the weak nuclear force, but also non-vanishing in its strength.
That's not regular matter.
Its MACHOs that are made up of regular matter (well, brown dwarfs and black holes).
There are also theories that put an undetected form of neutrino as dark matter which would be a bit more regular.
> Its MACHOs that are made up of regular matter (well, brown dwarfs and black holes).
I mean...isn't this "technically correct" on a level that's beyond even the usual extremes of pedantry? Or maybe I'm missing something?
There's no cheese in my fridge, only blocks of cheese that are made up of cheese...
A MACHO is a low-energy star or whatever that would explain the apparent presence of dark matter without actually requiring anything exotic like WIMPs. The idea is that these objects are (relatively) massive, numerous, and so low-energy that they are hard to detect and their combined mass would theoretically explain the effects we currently attribute to dark matter.
Or in other words, a WIMP would be like claiming that your fridge is disintegrating your cheese, and a MACHO would be the kid raiding the fridge for cheese at midnight when you're asleep.
To twist that by claiming such a particle would still be viewed as matter just like all the rest of the matter that goes into the stress-energy tensor is where the pedantry started in this thread. The original statement is pretty clear in its intent. The pedantic reading that followed that comment results in "normal" matter just being all matter by definition and hence "normal" is redundant since there can't be abnormal matter. That clearly isn't what the first comment intended since they actually meant something by "normal".
Edit: there is an excellent in-depth (but math-light) explanation about the Higgs mechanism by Leonard Susskind. I highly recommend it if you are interested, it lasts about 1h (plus some Q&A) and is extremely approachable, while being presented by an established authority in the field.
This is incorrect — the coupling with the Higgs field is responsible for the rest mass of electrons and isolated quarks.
> and even less to do with the mass of hadrons
Yes, this is true — the contribution of the separate masses of the constituent quarks to the mass of hadrons is small, like you write.
To use a more relatable analogy, it's a bit like using quantum mechanics to build a skyscraper. In principle it should be possible, it practice it is incalculable. Newtonian physics does the job fine in that scenario.
In general, materials researchers for something like concrete are going to be better off exploring the (very large!) high dimensional space of possible formulations of existing concrete ingredients and pushing out the pareto frontier for the best possible concrete that way. Also, one probably shouldn't be using bleeding-edge concrete tech for a skyscraper foundation - in a safety critical application like that you just build it 1.2x bigger than you need and it'll still be much cheaper and safer than a process like what you just described.
Materials research is super interesting, though, even if it's not building up from quantum-particle scale research. And atomic / molecular features of inputs can yield interesting material candidates.
Source: I work (as a software dev, not a materials researcher) at Citrine Informatics, selling software to assist companies who are trying to do practical materials things like make better concrete.
Material sciences, condensed matter physics, chemistry and etc work up from the abstraction layer of "atoms". It's a quite well defined and relevant layer. So, until that work brings some different configuration¹ for atoms, they will have no impact at all.
1 - It doesn't need to be as new elements, but even for the resonance between the nucleus and electrosphere they didn't create anything new, and only things affecting the electrosphere matter. (Even then, they didn't create anything new on a nucleus either.)
Like all things in science has any stopped to think if we should push it?
We see it day in and day out where science has developed something without slowing down to do research into the affects other than the one they are scoped in on while making what they are making. I'm specifically thinking of the new chemical sciences that have brought out some formulas that are great at a specific thing, but are absolutely tragic to nature in so many more ways. The science shows these chemicals to be tragically toxic, yet that info gets shoved in a drawer so inventors can make money.
Great, we made something, but we should be able to say thanks but no thanks. Let's put that in the column of good idea, good science tech to achieve, but best left alone. Take that learning and try to achieve the samething in a different manner so that it doesn't kill everything else.
Shelving discoveries based on the perceived effect they (could) have (who would even evaluate that?) is a slippery slope if I ever seen one.
This is precisely what should happen though. We made ICE powered cars that used leaded gasoline because reasons, but the results of that were horrible for everything except the ICE. We shelved that tech because it was just bad.
We've shelved the widespread use of lead in paint. We've shelved the widespread use of asbestos in lots of things. There's nothing wrong with realizing the juice isn't worth the squeeze. We know that it is something that happens. Sometimes we make something that comes with a heavy cost. Obviously we don't have a way to know that until it exists. Then again, we should be able to start recognizing that particular chemical chains results in bad things so we should be super careful with the new thing because it is looks like something we've seen before. We can do this with virus and what not. Why not with chemistry?
The LHC employs a lot of people working on smart things. CERN gave rise to the world wide web and there are many other innovations in computing, construction, and theory that come from the work being done there.
> The Large Hadron Collider took about a decade to construct, for a total cost of about $4.75 billion. [1]
> Since the opening of Mercedes-Benz Stadium in 2017, the Falcons organization has publicly pegged the cost of the building at $1.5 billion [2]
It's the same order of magnitude of cost as a sports stadium. It's a tiny slice of the worldwide economy.
We don't know where the key discoveries in "theory state space" are, so we continue to search. Finding the right evidence or surprises could lead to rapid changes in how we think and view the universe.
I'm sure some medieval people must have found scientific tinkerers wasteful as well.
Diversification of investment is good. It's not like all research dollars are going to high energy physics.
[1] https://www.forbes.com/sites/alexknapp/2012/07/05/how-much-d...
[2] https://www.ajc.com/sports/atlanta-falcons/mercedes-benz-sta...
The inventor of leaded gasoline (Thomas Midgley) also invented CFCs, but at least we didn't already know those were bad for the ozone layer at the time.
I doubt that the science can show a compound to be tragically toxic any more than it could show a compound to be hilariously toxic, frightenly toxic or delightfully toxic.
Apart from an observer, who is typically human (though sometimes in our mind an athropomorphized animal or superhuman deity) I'm not sure anything in nature can be tragic. It just is. No one mourns the trilobites.
If those models had predictive power that translates to atomic scale you wouldn't need a multibillion collider to prove them.
One of the few molecular level effects that depends on the virtual particles that are important in the standard model is the Lamb shift https://en.wikipedia.org/wiki/Lamb_shift
In this case the virtual particle is a virtual photon, not a virtual weird particle, so it's just scratching the standard model.
I'm not sure if the g-2 Anomalous magnetic dipole moment of electrons https://en.wikipedia.org/wiki/Anomalous_magnetic_dipole_mome... can be measured with a cheap equipment.