New exotic matter particle, a tetraquark, discovered at CERN

https://phys.org/news/2021-07-exotic-particle-tetraquark.html

by mherrmann • 5 years ago

555 197 5 years ago

akomtu2• 5 years ago

The article (light on details, as usual) mentions that a slightly different configuration of a tetraquark would be very stable (again, not sure if that means nanoseconds or hours). If such stable multiquarks exist, without an electric charge they would be effectively untraceable, right? The only way to see such a particle would be to hit it precisely with an even smaller particle and get it to bounce back.

sethhovestol• 5 years ago

The more likely (I'm not a physicist) is to watch the decay of the particle and trace it back from there.

whatshisface12• 5 years ago

The only way to see such a particle would be to hit it precisely with an even smaller particle and get it to bounce back.

Bounce back from what force? Whatever forces would make it interact with a single particle would make it interact with a detector, which is itself made out of particles.

They say the extra-stable tetraquark would only be susceptible to decay via the weak force, which means you'd have to wait around until it decayed, and then you'd often be able to see some charged remnants.

akomtu2• 5 years ago

Can such tetraquarks form semi stable macroscopic structures like atoms? For example, if they aren't completely neutral, a group of them would be able to maybe attract an electron and become a quasiatom of some sort.

enkid• 5 years ago

I don't think that's a unique property to tetraquarks. Neutrons or neutrinos also are not electrically charged. I'm not sure what you mean by untraceable, but neutrinos rarely interact with other particles and many, many of them pass through you every second without you even noticing.

dukwon6• 5 years ago

A stable heavy-quark tetraquark shouldn't live longer than, say, the B_c meson, which has a lifetime of about 5×10^-13 s

danslo• 5 years ago

Such proximity in mass makes the decay "difficult," resulting in a longer lifetime of the particle, and indeed Tcc+, is the longest-lived exotic hadron found to date.

So... how long does it live?

whatshisface12• 5 years ago

The resonance width is inversely proportional to the lifetime, and if the resonance width is about 400keV, the particle would live for about 10^-21 seconds. For comparison, neutrons decay via the weak force in about 800 seconds, and delta baryons, a randomly chosen strong force decay, live for 10^-24 seconds. That makes this tetraquark long-lived for a strong decay, but that's way, way faster than a weak decay.

https://en.wikipedia.org/wiki/Resonance_(particle_physics)

Gravityloss3• 5 years ago

So not usable as spaceship fuel

phkahler• 5 years ago

Are these decays equivalent to drops to a lower energy state where that energy is mass?

im3w1l3• 5 years ago

Despite free neutrons decaying in 800s, there are many stable elements containing neutrons. Would it be possible to imagine a tetraquark as an ingredient of a stable particle?

BurningFrog2• 5 years ago

Then I wonder if this "particle" is just some components that takes 10^-21 seconds to bounce away from each other after colliding?

kmm• 5 years ago

Fun fact, the reason strange quarks are named strange is because when we discovered the first hadrons containing those quarks, they were strangely long-lived.

Long-lived here meaning 10^-10 seconds, instead of 10^-20 seconds. A whole tenth of a nanosecond!

ansible2• 5 years ago

That is actually quite a long time at the quantum scale.

tux33• 5 years ago

The article points to an ongoing conference as the source, unfortunately (despite having no registration fee) the live-stream is password protected for non-participants :(

https://www.eps-hep2021.eu/live_stream/

Edit: It seems the talks may be released, in the end

We would like to record your presentation at the EPS-HEP2021 conference and make it publicly available via the INDICO page and the DESY media streaming server until one week after the end of the conference.

jandrese• 5 years ago

They probably don't want internet randos jumping in and flooding the chat with porn.

tux33• 5 years ago

That makes sense for the zoom sessions.

But, although I've never run a conference, I naively can't see that broadcasting the plenary session's video a little broader (to the three to five latecomers likely to stick around!) would really cause problems.

Not to be a stereotypical "Concerned Facebook Taxpayer", but in general I'm really fond of CERN's transparency, and I appreciate all the work they do to keep science open. They're usually way ahead of the field and it's refreshing to see, I love following what comes out of the LHC data.

So all that to say, maybe I've set my expectations a little high when it comes to physics and public access =)

whatshisface12• 5 years ago

Two more technical treatments:

https://cerncourier.com/a/new-tetraquark-a-whisker-away-from... https://lhcb-public.web.cern.ch/Welcome.html#Tcc

oldspleen• 5 years ago

someone please ELI5 and how this discovery is important for furthering our understanding of quantum numbers

whatshisface12• 5 years ago

The laws governing the strong force are somewhat well-known at this point, but calculations involving them are difficult and in many cases beyond our reach. Furthermore the fundamental constants are not known to a very high precision. Both of these problems can be addressed by collecting experimental data about how these particles behave in real life, both to pin down the constants, and to accept or reject calculation techniques.

dukwon6• 5 years ago

It won't improve our understanding of quantum numbers in general (a quantum number is just a discrete conserved quantity). The final paragraph mentions measuring the quantum numbers of this particular particle, namely its angular momentum and parity.

thereddaikon• 5 years ago

Is this the one that makes all the Sci-Fi gadgets do the impossible? I need to know if I should be excited or not.

dmitriid• 5 years ago

You just need to apply more quantum.

4e530344963049• 5 years ago

https://trimread.org/articles/31

amai2• 5 years ago

What is the charge of a tetraquark? Is it neutral?

whatshisface12• 5 years ago

A tetraquark is four quarks. There exist three -1/3e quarks (dsb), three +2/3e quarks (uct), and then their +1/3e and -2/3e antimatter counterparts. 1e is the charge of one electron. The stability of a tetraquark is mainly a color/strong force thing and the electric charge comes along for the ride. Stable atomic nuclei, which are held together by the strong force, go up to +83e and they still don't fall apart due to electric repulsion.

However, there is one constraint that might show up in charge. Tetraquarks always have two antiquarks, which is necessary for the color charge to come out to zero. Working out every possible combination is left as an exercise for the reader. :)

im3w1l3• 5 years ago

The highest possible charge is 2/3 + 2/3 + 1/3 + 1/3 = 2. Every swap of a quark to a lower charge one reduces the total charge by 1. So the possibilities are 2, 1, 0, -1, -2.

jjk1662• 5 years ago

This particular one is +1e but there are many other forms a tetraquark may be able to take.

mirthless• 5 years ago

Does it fit into the standard model? I thought higgs boson was the last undiscovered particle according to the standard model.

xhrpost• 5 years ago

You're referring to elementary particles. This is not elementary as it is composed of Quarks, which are part of the standard model and are elementary.

x3n0ph3n3• 5 years ago

tetra-quark: 4 quarks. It's composed of particles that are already part of the standard model, just an a previously unseen arrangement.

ur-whale• 5 years ago

Particles are compositional.

jdeaton• 5 years ago

I wonder if the sophons from Trisolaris would have blocked this discovery.

xondono• 5 years ago

Congratulations for the discovery of the next epicycle!

pseudobry• 5 years ago

I recently finished The Three-Body Problem and The Dark Forest, which explore the concept of aliens using their super advanced technology to mess with the results of Earth's particle accelerators, thereby stopping humanity's ability to develop technology based on new physics.

Is this discovery exciting? Or are we living in The Three-Body Problem?

bequanna• 5 years ago

Interesting.

For what reason are the aliens trying trying to stop us from discovering new physics? Stop us from blowing ourselves up? Blowing them up?

sylens• 5 years ago

Without ruining too much of the books (they are worth a read), there is conflict between us and the aliens and limiting technological progress is an important part of their strategy

godelski3• 5 years ago

The aliens are coming to Earth to take it over. They aren't much more advanced than us and so don't want us to be more advanced than the fleet that arrives (it takes them a few hundred years to get to Earth).

FinanceAnon• 5 years ago

If aliens don't like us, then why wouldn't they just destroy us, rather than troll our physicists and mess with the results?

Why would they specifically mess with the particle accelarators at this point? Why not with earlier physics?

kingkawn• 5 years ago

Because they're hundreds of years of space travel away so they send sentient protons to sabotage our particle physics so that we can't develop advanced enough technology to stop them by the time they arrive.

joshspankit• 5 years ago

Here’s a possibility: They are in the next universe over, and so far the only thing that passes between is gravity. Fine-grained control over gravity could allow them to mess with things but not destroy us (if they even wished to. I don’t even think Earth would vote to destroy an unknown civilization if the roles were reversed)

maininformer• 5 years ago

maybe we are their toys, or maybe our emotions is their energy source

AdamN• 5 years ago

In the book that's the state of human science when they learn of our existence. Also, they want our planet and it will take them a long time to get to earth - so long in fact that they predict that if our physics is allowed to mature they won't be able to beat us militarily by that time. They need to stop progress asap.

gizmo6864• 5 years ago

Spoilers below:

The Three Body Problem trilogy breaks down if you think about it too hard. The in-universe explanation was that the aliens did want to destroy us, and had an attack fleet heading towards us. However, the attack fleet was relativly slow, and they were concerned that by the time it reached us we would have advanced to the point where we might win in a fight. To prevent this, they sent smaller probes to us at near light speed. In theory, these weren't capable of causing significant damage, but they could cause enough of an effect that they could make the results of particle accelerators useless. Without being able to use particle accelerators, we wouldn't be able to advance our knowledge of fundamental physics, so the aliens were confident that when their attack fleet reached us we would be defenseless.

By itself, what I have written is not particularly absurd, but if you look at the other things those advanced probes ended up being able to do, they could have easily just killed everyone.

JetSetWilly• 5 years ago

Because your interstellar equivalent of the CIA can obtain the political capital to prevent a civilisational rival from emerging via subtle manipulations, but it can't obtain the political capital and consensus needed to commit wholesale genocide.

There's a big difference between the scenarios.

midrus• 5 years ago

Maybe because we're their big brother tv show or just their zoo

nolok• 5 years ago

Haven't read those specific books, but "keep the species at the level they were when discovered for preservation" is a very common trope of such things, and usually mapped on how humanity considers that "preserving a species" means keeping it exactly as they were when first discovered.

yarky• 5 years ago

If you insist on looking at it from our perspective, how about curiosity? Let's see how far they (us) keep trying to make sense out of this nonsense. Trolling in the name of science I guess.

People from North Sentinel Island might ask themselves the same question about us.

artursapek• 5 years ago

I troll people I don't like all the time

f6v• 5 years ago

It’s a great book, but it suffers from the same old issue. A civilization that is capable of packing a robot into particle by manipulating higher dimensions doesn’t need to take our planet. They could terraform Mars or any other planet they want.

s5300• 5 years ago

Perhaps we look to be an exceptional vacation spot, and there are space Karen's who desire an "all natural" planet instead of a terraformed one.

hllooo• 5 years ago

iirc the solar system contained the closest planets, which is why they chose it. I don't think it matters if they want mars or earth, there's no way we would let them do that (send a massive military fleet definitely just to mars). they wanted to ensure their technology remained superior by the time they arrived

alasdair_3• 5 years ago

I had the same problem with the books. If the sophon is that omniscient and that powerful, it could do far more than just mess with experiments.

I also never understood the wallfacers - why can’t they communicate via encryption, using a private key stored in each individuals mind alone?

shoto_io2• 5 years ago

Why not just for fun? Like riding horses even though you have a car.

micromacrofoot• 5 years ago

Spoiler: It took them so long to get to earth that they were concerned about humans becoming a formidable opponent in the meantime. Had human advancement not been halted humans would have much faster access to Mars than they would.

whymad• 5 years ago

True for what it is, but this is handled in the books. They literally don’t want our planet, they want our star.

And the dark forest: without a history of correlated interaction we have no reason to believe they will allow us to live, so we can’t allow them to live, so they can’t allow us to live.

Eliding a more major spoiler, they absolutely intended to annihilate us on arrival and they would have gotten away with it if it weren’t for, ah, “those meddling kids”. Everything else was cloak and dagger.

They definitely would have terraformed every planet in the system once they were sure we were gone. Or more likely deconstructed them, at that point in their development.

ASalazarMX5• 5 years ago

Super spoiler below:

Their tri-solar system was too unstable to terraform, they needed a stable solar system to migrate to. Of course ours was the nearest with an habitable planet (otherwise there wouldn't be much of a story), so they can immediately colonize Earth, and probably begin the centuries-long process of terraforming the neighboring planets.

AlexCoventry• 5 years ago

There's also the weird aspect that [rot13'd for spoilers] gur fbcubagf frrz gb or noyr gb vasyhrapr naq dhrel znggre, ohg pna'g frrz gb ernq crbcyr'f zvaqf be xvyy gurz.

Panoramix• 5 years ago

Spoilers ahead

It was such a letdown, the book starts great, and then the explanation turns out to be magical Alien proton computers? Yikes. It was so promising.

I eventually read the whole trilogy, I have very mixed feelings about it. It had some pretty cool ideas but it's hard to get past all the giant plot holes and outlandish fantasy. I guess you have to be in the mood to constantly brush off the bad parts (and boy there are many) and plunge forward.

WORMS_EAT_WORMS• 5 years ago

The whole book is fun and creative fiction. Just enjoy it like you would enjoy any non-real TV or movie.

If you haven’t read the series, saw the spoilers here, and are no longer thinking about it… don’t get discouraged. Pay off in Book 3 via the space concepts are worth it still. Mind blowing fun stuff

cmurf• 5 years ago

Human story tellers are very attached to humanity, so the stories tend to anthropomorphize aliens. Most alien stories rehash old religious and hero stories. What do we have to offer aliens? In the category of vague as well as less is more, Arrival/Stories of Your Life and Others are about as compelling as it gets - humanity hasn't yet achieved full potential, going further out on a limb is folly (however entertaining it might be, it becomes less compelling).

The more truly alien, the less in common we have in all respects, the more boring that story turns out to be because? We're a selfish, self-interested, loathsome species who consistently overestimates its importance. The more different a fellow human is, the vast majority of people reject that individual because of their (weird) non-social behaviors.

So these alien stories strike me as deification, angels, devils, i.e. the supernatural, and don't adequately explain why or how any alien civilization would take interest in us, except via our own attachments to ourselves. This is central to good science fiction because they are stories ultimately about exploring something about humanity, it's not really about aliens at all. They're entirely incidental even if they seem important, aliens are just a literary device. But getting to science-non-fiction, a factual case of aliens, that's quite hard for most humans to imagine at all.

Consider how poorly most people coped with covid, and then consider how much more traumatic an alien visit would be, even assuming they were nice.

In Arthur C. Clarke's Childhood's End (1953) those aliens were "nice" but with a really big caveat. (And neatly explained devils.) But again, humans are the central part of that story, not aliens. It wouldn't and couldn't have been interesting to focus on the interests of the aliens without us being part of the story - we're just too self-interested by nature. The aliens' interests would have been boring to us, we just don't have the necessary common frame of reference with such beings. How could we?

amelius2• 5 years ago

Or perhaps the laws of physics that we observe are becoming more complicated over time, as a consequence of some deeper law of physics.

alasdair_3• 5 years ago

The simulation we all live in is getting a new patch with higher resolution models.

majkinetor• 5 years ago

You spoiled it for me, I am on 1/4 of the first book :S

whytaka• 5 years ago

Oh blood, I just got this book. Is this a huge spoiler?

kryptn• 5 years ago

Same. It's been on my list, but this is more detail than I wanted to see.

efsavage• 5 years ago

Rest easy, there is a lot more to the books than that.

ASalazarMX5• 5 years ago

In the books, the Sophons got in the way of the accelerated particle beam but somehow avoided being destroyed themselves. They wouldn't have allowed a new particle to be discovered.

godelski3• 5 years ago

They were destroyed but could bring themselves back together. The thing is that the particles are intelligent so could break apart in random ways that didn't match what particle physicists expected (they would then recombine outside the detector as to not be exposed).

rsynnott7• 5 years ago

In the Three Body Problem, the naughty aliens break reproducibility in particle accelerator experiments; they start giving random results. So we're good for now.

tomudding• 5 years ago

Unrelated to this topic, but Death's End is also a great book if you haven't started reading it. I can also recommend Ball Lightning which more or less takes place before the events in the The Three-Body Problem.

misiti3780• 5 years ago

which book was better?

xwdv• 5 years ago

Can someone explain the practical use for this? Better batteries or something?

piyh• 5 years ago

Another tick forward in fundamental physics that will pay off as some theoretical framework getting slightly more grounded and paying off in a tangential way 70 years from now.

spxtr• 5 years ago

The new particle contains two charm quarks and an up and a down antiquark. Several tetraquarks have been discovered in recent years (including one with two charm quarks and two charm antiquarks), but this is the first one that contains two charm quarks, without charm antiquarks to balance them.

This is not the first time a tetraquark has been measured, but instead it's the first time a tetraquark with two charm quarks and no charm antiquarks. That's still nice work, but I was initially confused by the headline ("didn't they discover those already?").

lisper• 5 years ago

I read it as: "CERN has discovered a new particle, and that new particle is an instance of a known class of particles called tatraquarks". The wording is a little sloppy and ambiguous, but headlines are pretty tightly constrained so I'm willing to cut the writers a little slack on this. I've seen much worse.

skinwill• 5 years ago

Normal human here, can someone speculate on potential industrial uses?

Zenst• 5 years ago

Too early for that, though does open up other science that may well. Might finally pave the way for gravity shields, food replictor...or nothing.

The aspect that this tetraquark breaks down into something with more mass will certainly be interesting for study.

nabla9• 5 years ago

Nobody expects noting. No reason to expect anything whatsoever.

The particle is incredibly short-lived, requires a massive particle accelerator to create, and is hard to detect.

This is just another high-energy physics experiment. The hope is that someday something comes out that does not fit into existing models and is a sign of new physics.

WaitWaitWha• 5 years ago

I am unclear if they produced a tetraquark particle, or they simulated the particle.

... used Google’s quantum computer to demonstrate a genuine ...

Algol• 5 years ago

I don't see a mention of quantum computers in the article. I think LHCb detected the particle.

archsurface• 5 years ago

Why do these things take so long to find? Do they not show up in all collisions - why not, wrong matter, wrong speed? Do they regularly appear, but the "camera" has limitations? Is the "camera" all-seeing, but measurement interpretation inefficient? All/some of the above?

ManBlanket• 5 years ago

I think it's a matter of theory supporting observed data. They point the, "camera" at a bunch of experiments, which generates a ton of data, then it's up to theoretical physicists to explain the results. Once the results of a theory have been explained and then reproduced it stands on solid ground. I'm just speculating, of course. But that is sort of how astronomy works, at the polar opposite end of a similar field.

dukwon6• 5 years ago

Your comment kind of implies that theorists analyse the data. (They don't even have access to it.) Analysis is the job of experimental physicists (like me) and can take years.

We don't wait until we have theoretical interpretations before publishing the discovery of a new particle. In fact, our results are kept confidential until the end of the collaboration's internal review process. In the absence of leaks, the first any theorist should hear of this new particle would have been the conference talk or press release.

peter303• 5 years ago

Some physicists will get an idea for a new particle or decay mode. Then they will postulate various decay modes that could be captured by the detectors. The short-lived new particle arent directly detectable, but daughter particles may be. Particles leave characteristic signatures on the two large CERN detectors, each which consists of an onion of thousands of directional and intensity sensors. Then they computer search quadrillions of already recorded events at the detectors for a significant number of candidate events. This may take months for a postdoc or grad student to do.

I recall the Higgs had about 80-some possible decay modes. Only a handful of them could be measured above background noise. A couple of teams pursued two classes of them and found results.

dukwon6• 5 years ago

Do they not show up in all collisions

This is the biggest factor

why not, wrong matter, wrong speed?

Quantum mechanics is probabilistic. The probability of these particular particles in these particular collisions is very small. So we need to do a lot of collisions in order to have a statistically significant signal.

but the "camera" has limitations?

Sure. While we regularly upgrade our detectors or build newer, fancier ones, there will always be some limitations.

but measurement interpretation inefficient?

It's certainly slow. It can take months/years to infer a result from the data. The major bottleneck is people. Even the thousands-strong armies of physicists who work on the LHC experiments would take decades to fully exploit the available datasets.

rkagerer• 5 years ago

Neat! What can you imagine might be applications for exotic particles like this? (even if if it's a stretch or fictional)

svachalek• 5 years ago

Given the massive energy required to do experiments like these and the microscopic scale in both physical and time dimensions I think we're centuries away from doing something practical with the particle itself. It may be the missing piece of some future technology we can't even imagine yet.

I think the more immediate motivation is to help either validate our current understanding of how the universe works, or to break the model in an interesting way.

dukwon6• 5 years ago

In the world of double-open-heavy-flavour hadrons (to which this particular tetraquark belongs), you get bullshit headlines like this https://www.sciencealert.com/new-quark-fusion-releases-signi...

ThinkBeat2• 5 years ago

"Quarks are the fundamental building blocks from which matter is constructed."

I sometimes wish would include "In our current model", "We now think that", or some other qualifier.

Such absolute statements have been made frequently prior to our current understanding.

I have no special knowledge to lead me to believe that quarks are not the end all of parties.

But I was happy with atom being the fundamental thing, and then electrons, neutrons, protons were the thing as well.

The other day I read about Fractons "quasiparticles or Partial Particles", so now I have to figure those out as well.

I have lost track if the graviton has been found yet. I dont think it has.

From a purely layman's sense of esthetics the current model for particle physics is messy and a little spooky.

I have an odd hobby. I collect old paper encyclopedias from pre 1970 For every language that I speak. It takes up MASSIVE amounts of space.

The oldest I have been able to acquire on a limited budget Is 1880.

It is always fun to track concepts over time.

They all state what the world is like, and how it works as bombastic facts.

Yet over time, most of it gets replaced or at least highly refined and things are removed.

Particle physics is an active field with much still to learn or figure out. Let us keep that in mind.

brianpan2• 5 years ago

"We now think that" is the qualifier on the entirety of physics. It's redundant.

h2odragon• 5 years ago

I'll certainly give the authors of the papers the benefit of a presumption of humility; it's the people "translating into layman's terms" and "passing on knowledge" that introduce Authority, and other errors, as part of the process.

"Think for yourself, schmuck" is the only dogma worth petting.

abainbridge• 5 years ago

Haha. True. Some parts of physics are way shakier than others though. For example, the whole big bang, dark matter, dark energy area needs the qualifier of, "We know we've got something wrong here, but its the best we've got". (eg see https://en.wikipedia.org/wiki/Big_Bang#Problems_and_related_...). I'm trying not to be controversial here. I'm just using this as an example of physics with well known problems.

Regarding, "Quarks are the fundamental building blocks", do we actually think that? If so, why? I'm genuinely curious. Is it just because we haven't seen anything more fundamental? That would violate your "We now think that" qualifier - ie if that is the reason, the qualifier should be "We have NO reason to think that...".

complexmango• 5 years ago

If only epidemiologists had such humility

gizmo6864• 5 years ago

I sometimes wish would include "In our current model", "We now think that", or some other qualifier.

There is actually good reason to think quarks aren't fundemental. Even ignoring the empirical shortcomings of the standard model (specifically the incompatibility with General Relativity), it just doesn't "look" like a fundemental model.

Specifically, it is essentially a periodic table of elementary particles, with 3 "generations" of matter particles. Like the periodic table of the elements, this structure is highly suggestive that there is some deeper underlying structure.

geertj• 5 years ago

I agree that we don’t know. But there is also evidence that quarks are fundamental. Based on all our measurement, they are point like particles with no internal structure or size.

atulatul• 5 years ago

I came here to write something else. But after typing I felt it would be sort of bikeshedding. So did not add it. And now I am going to see if any other comments sound like bikeshedding. (including this one probably.) :)

New exotic matter particle, a tetraquark, discovered at CERN

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