A particle made of force: physicists say they've found mysterious 'glueball' | Hacker News Reader

A particle made of force: physicists say they've found mysterious 'glueball'

nature.com

150 pointsBrajeshwar52 comments

> After almost two decades of searching, a team of physicists in China says it has observed strong evidence of a mysterious particle called a glueball, which is made entirely of force-carrying particles. > ... The discovery of glueballs would provide direct evidence that gluons can interact with themselves, researchers say. This is a key prediction of quantum chromodynamics

> "quantum chromodynamics"

I had to google it: "the study of the strong interaction between quarks mediated by gluons"

It’s the theory of colour charge essentially, counterpart to electrodynamics. Quarks have colour, rather than electrical charge. Mediating particle is the gluon, analogous to (but entirely different from) the photon

Its called chromodynamics because the interactions are described by the special unitary group of degree 3, which is the same group that describes how we perceive color interactions.

It's just the three dimensional nature of it plus the usual physics practice of giving things cheeky names. The vector space of (visible) colors is not acted symmetrically upon by SU(3); it doesn't transform symmetrically under charge-preserving unitary matrices. A blue strawberry with red leaves would not seem the same to us as a red strawberry with green leaves.

Now explain how quarks have flavour!

Why do they call it a "mysterious glueball" if the theory predicted it?

Because it's never been observed.

mysterious: strange, not known, or not understood.

They don't really know what it is or understand it.

https://archive.ph/9Lfum

This led me on a 1.5 hours long, entertaining chat session with Gemini learning about stuff in Physics - hopefully without much hallucinations. But definitely with a lot of typical - "You have arrived at a great insight.." like egging on by the AI :D

But learned a bunch about bosons, fermions, QCD, gluons, Kugelblitz, composite bosons and finally Noether’s Theorem on symmetry. Was a wild ride

How do you plan to make this newfound knowledge 'stick'? Do you have enough relevant/related knowledge that you'll remember it? Or is there a way to have Gemini make a bunch of cards for use with spaced repetition software?

Best way is to build a particle collider in your back yard. If you don't have the budget, write a simulator.

I was waiting for someone to make a glueball joke, TBH.

"You are absolutely right! ..."

You can use Gemini notebook notebooklm for this

Oh cool, will look into this. Have only used it to make podcasts in the past. I'm a little hesitant to build in a walled garden though. I'd rather store things in an open format that can be used with many platforms, not just the one.

Yea, I like the quiz feature a lot. It feel more efficient than both the podcast one (which mostly creates a very superficial high level talk on a level I typically already grasp), and the flashcard one in my experience.

share the thread ?

Isn't it significant in some sense that this was discovered in China first, and not the US?

In the sense of: we didn't know splitting the atom would change warfare forever, back when Einstein and others published on it. We don't know if there are discoveries of similar impact lying in wait somewhere. If China gets to such a discovery first, we are in Sputnik territory, to say the least.

We knew. That's why Roosevelt started the Manhattan project after scientists wrote to him warning about it, to be sure that the Germans or the Soviets didn't develop it first.

Plenty of things get discovered all over the world and this isn't a particularly earth shattering result. Discovering evidence of a particle predicted for 50 years is interesting but still pretty mundane.

The LHC which is doing much of the particle physics discovery is in Switzerland and France, if you need to be reminded, not the US.

The first strong force theory was published by Hideki Yukawa in Japan in 1935 (which won him the nobel prize) ... so uh, not exactly a sputnik problem.

Sputnik problems (and the nuclear race) are engineering and industrial races, not fundamental physics ones.

> The LHC which is doing much of the particle physics discovery is in Switzerland and France, if you need to be reminded, not the US.

Which is ironically an example of particle collider science happening overseas primarily because the US relinquished its lead on scientific discovery, despite having a similar-scale particle collider practically finished and ready to go [0].

[0]: https://en.wikipedia.org/wiki/Superconducting_Super_Collider

That would be classical 80:20 or more like 90:10 rule, few kms of tunnels ain't close to delivery in any feasible way, just the first baby steps.

The amount of continuous effort (and budget) that goes into just keeping CERN up and delivering is non-trivial. I live nearby and sometimes chat with folks working there (its >15,000 folks although not all do science).

Well they have plenty of spare time to do things like, for example, invent the web browser.

That was a time saving part and parcel of the job of exchanging text and images between researchers.

If you're reaching for examples of spare time activities, this was squeezed into 20 minutes of downtime: https://www.youtube.com/watch?v=1e1eLe1ihT0

"practically finished and ready to go" is a bit of an overstatement. They made some holes in the ground, and did preliminary research and manufacturing, but it was heavily mismanaged and fantastically over budget, so congress killed it

Einstein? Rutherford, I think

Why not let the man himself tell you (as a surrogate for Roosevelt) the story

https://www.atomicarchive.com/resources/documents/beginnings...

Ahh... I took "published" on splitting the atom to mean the scientific write up of having split the atom - which was Rutherford - rather than the looser meaning - having just written about the idea in general. My bad.

But nuclear fission was discovered by scientists working in Nazi Germany (except Meitner who had fled to Sweden by then).

It's foundational science. The US scuence system calls for utility and time to merket. In such a system there is little space for gluons.

That is untrue. US science is also funded by NSF grants - or were, before the Orange Idiot and his crew of apes began defunding science they didn't understand.

Much science is done by international (i.e., borderless) cooperation between teams of scientists, as well. Science is becoming, and ultimately should be, nationless.

you are trying to see something that's not quite there in this case. there is shit ton of very good research that happens all over the world. but i also sympathize with what you are trying insinuate and that's also probably happening.

HEP is undeniably an international effort, and it's silly to try and spin this into something akin to the space race. While this is a useful and frankly brilliant potential confirmation of existing theory, that's what it is: confirmation (sort of). Without CERN, without universities across the world including all across Asia none of this would be possible.

Very few endeavors are as truly international as this because the problems are so hard to even explore, and the machines required to do so are the most complex and highly engineered on Earth. Lets not lose that international spirit in science because the blowhard narcissists who run our countries would find that temporarily useful to them.

are we going to have force-fields now?

We have them now. You are not floating into space because of one right now. Also magnets.

No.

I thought a Plasma Window is a form of force-field.

> I thought a Plasma Window is a form of force-field.

Kind of. It weakly repels Gnome users.

Plasma is matter, not a force

Yet what is matter but a (strong) force

Matter is usually made of fermions (half-integer spin) whereas force is mediated by bosons (integer spin).

Matter is not a force. Matter and forces are two different things in physics.

And the "strong force" is another thing altogether.

I think their point might be that matter is what defines the location of the force field. I.e. it's the EM field doing the actual work.

Yea, that is it, and I agree with them. When we say that a particle is at some x,y,z, we just mean that the space at that location behaves in a certain manner, for some reason.

And since we don't like mysteries, we say that there is a "particle" there with so and so properties..

It's more like "behaved", because particle measurement events are always historic. Quantum fields are statistical distributions of possible future particle measurement events within spacetime.

That is, until we find a way to unify the fields

Interesting how should someone uses it IRL at the end of the day

AI-made?

Oh no. A new particle. Who would have guessed %]

And here I am, thinking I discovered "glueballs" in elementary school when we were given rubber cement to use.

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