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New exotic matter particle, a tetraquark, discovered at CERN

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Re: New exotic matter particle, a tetraquark, discovered at CERN

#161

Post by shmageggy »

cynicalkane wrote: post #146
Panoramix wrote: post #136

Earlier quoted context omitted.

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 b…

Spoilers. There are a few parts of the book, according to the translator, that are done in the manner of a Chinese folktale, which he tried to translate to a different style in English. I'm no expert, but I got the impression the sophont chapter was in this category. It has this otherworldly silliness with the multiple attempts to create a sophont going wrong in different dimensions, calculated to fit the repetitive…

> Anyway, I doubt it was meant to be hard sci-fi.

Which was extremely disappointing, given that it was billed as such by many, and until the aforementioned mumbo-jumbo was doing a seemingly nice job on that front.

Re: New exotic matter particle, a tetraquark, discovered at CERN

#162

Post by kkylin »

tux3 wrote: post #26
jandrese wrote: post #19

Earlier quoted context omitted.

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

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 o…

Many online conferences I've attended this past year have both a Zoom meeting for registered participants and a YouTube "simulcast" for people who don't care about asking questions. I haven't run one and don't know if the logistics are complicated; maybe the organizers just didn't think of doing it. Anyway, these days most conferences seem to be pretty quick at putting videos out, though of course our attention will be elsewhere next week...

Re: New exotic matter particle, a tetraquark, discovered at CERN

#163

Post by hnuser123456 »

Gravityloss wrote: post #154
hnuser123456 wrote: post #113

Earlier quoted context omitted.

Huh, "black holes move when you push them" is interesting. I suppose you could feed it with a beam, but focusing a beam down to attometer-size beamwidth seems like the hardest part, ignoring making a subatomic black hole in the first place. But sure, I suppose capturing the radiation and redirecting most of it back into the black hole to push it and maintain its size, and just enough spare to push the ship itself at…

Power scales to the square of exhaust velocity while thrust linearly, so if you have a very good power to weight power source like a black hole, you can use a very high exhaust velocity and thus can get by with very little reaction mass. Which is good. Also, you can make a spaceship out of an asteroid (or from asteroid materials) so multi WTC mass is not a problem.

I see. I was assuming we were thrusting with nothing but gamma radiation, which is the speed of light, unbeatable, but I see with such small black holes, we may end up with some matter evaporating from it. I suppose that's one more benefit to larger, colder black holes: more likely to have lightspeed radiation than massive particles.

We could go for something closer to the temperature of the sun / wavelength of green light, about 10^19kg, easy to reflect, but that's about 0.1% the mass of the moon and would only output about 3.5 microwatts. Could try to balance between an amazingly reflective mirror to EUV or shorter wavelengths, which is more physically realistic than reflecting gamma rays, and usable power output, but that's simply out of reach at the moment. I wonder if we had an atomically smooth mirror, the smallest wavelength we could reflect with efficiency, and thus the highest power black hole we could use. Maybe it makes more sense for the black hole to have much higher mass than the spaceship, but 1g acceleration will be difficult.

Looks like most atoms are about 0.1nm, so 10^18kg black hole, for 350 microwatts. Like turning on a laser pointer attached to the moon and expecting usable thrust. Still far too large and not powerful enough to be a useful power source like a a 10^8kg black hole for around a petawatt. Either we figure out how to reflect deep gamma rays or it won't happen.

Re: New exotic matter particle, a tetraquark, discovered at CERN

#164

Post by BurningFrog »

Gravityloss wrote: post #13
whatshisface wrote: post #11

Earlier quoted context omitted.

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…

So not usable as spaceship fuel

Needs to be a very short trip.

Re: New exotic matter particle, a tetraquark, discovered at CERN

#165

Post by BurningFrog »

whatshisface wrote: post #11
danslo wrote: post #3

>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?

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…

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

Re: New exotic matter particle, a tetraquark, discovered at CERN

#166

Post by iainmerrick »

roywiggins wrote: post #126
SkyMarshal wrote: post #109

Earlier quoted context omitted.

They could send the subatomic particles from Trisolaris to Earth at light speed, and then use the entangled pair of particles (one on earth, its mate on Trisolaris) to monitor events on earth in real-time. As already said, that preserves the planet, prevents a potential enemy from further developing technologically, and enables real-time monitoring of and interference with that enemy's activities.

>and then use the entangled pair of particles (one on earth, its mate on Trisolaris) to monitor events on earth in real-time. This, of course, breaks the known laws of physics, since lightspeed is a hard limit on the speed of causality. You can't use entanglement that way in the real world (if QM is anywhere close to correct)

Right, that was the huge issue I had with the story. In most respects it seemed to be trying hard to be speculative hard SF in the Arthur C Clarke vein (i.e. fine to introduce exotic new physics, but only very carefully and consistently) so it was very surprising to have that gaping hole at the centre.

The aliens had instantaneous communications, and could directly influence events on earth, but still had to travel at sublight speeds? It wanted at least an acknowledgement of the inconsistency, and a token effort at explanation. As others have noted, it’s not at all clear why they couldn’t simply have killed off the humans remotely.

Re: New exotic matter particle, a tetraquark, discovered at CERN

#167

Post by peter303 »

archsurface wrote: post #129

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?

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.

Re: New exotic matter particle, a tetraquark, discovered at CERN

#168

Post by IAmGraydon »

spxtr wrote: post #59

> 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 qua…

Like nearly everything from the media, it's a lie designed for clicks.

Re: New exotic matter particle, a tetraquark, discovered at CERN

#169

Post by elmomle »

IAmGraydon wrote: post #168
spxtr wrote: post #59

> 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 qua…

Like nearly everything from the media, it's a lie designed for clicks.

Let's not throw baby out with bathwater. This kind of thinking has been so harmful for social cohesion, and we need a cohesive society if we're going to have a prayer of handling the worst problems we've ever faced as a species in a way that future generations will be remotely proud of.

Re: New exotic matter particle, a tetraquark, discovered at CERN

#170

Post by bawolff »

elmomle wrote: post #169
IAmGraydon wrote: post #168

Earlier quoted context omitted.

Like nearly everything from the media, it's a lie designed for clicks.

Let's not throw baby out with bathwater. This kind of thinking has been so harmful for social cohesion, and we need a cohesive society if we're going to have a prayer of handling the worst problems we've ever faced as a species in a way that future generations will be remotely proud of.

We have no hope of facing those problems if our social cohesion is so fragile that it can't even handle calling an article out as clickbait.
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