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RE: Charmonia, bottomonia & toponia - the fantastic beasts of particle physics

in StemSocial • 7 months ago (edited)

I could follow it easily. Almost as if somebody finally explained particle physics experiments in English. 🙂

I have few questions though. Mostly, regarding how I am trying to wrap my imagination around it.

Particle-antiparticle pairs are supposed to annihilate (like that owl, anti-owl did in discord). What stops a quark and an anti quark pair from immediate annihilation. Is the color force between them repulsive to hold them apart?

Is it known that decay time of a known particle can change when they form a composite particle. Say if t1 is decay time for particle x and t2 is of particle y. The decay time of xy is either t3 > t1 or t2 if it gets stable, or t4<t1 or t2 if it becomes more unstable? Is this what you think is happening with toponium, that it is getting more stable as a composite particle? Or you were able to see an even 10-25s small?

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 7 months ago 

Thanks a lot for your feedback and the questions (which I will enjoy answering). You imagination is really cool here!

Particle-antiparticle pairs are supposed to annihilate (like that owl, anti-owl did in discord). What stops a quark and an anti quark pair from immediate annihilation. Is the color force between them repulsive to hold them apart?

This works especially with owls (and @mathowl I guess)... More seriously, there are two items here.

  1. Annihilation requires quarks and antiquarks to collide. Here, you are talking about quarks and antiquarks that are produced from a collision. They are thus very energetic and move away from the collision point.
  2. There is also the behaviour of the strong (colour) force. At high energies, it is weaker than at low energies. When a very energetic quark is produced, it will just radiate until it reaches lower energies. After a while (and possibly many radiation), its energy is small enough so that composite state formation can take over (by creating extra quark-antiquark pairs from the vaccuum thanks to quantum effects).

Is it known that decay time of a known particle can change when they form a composite particle. Say if t1 is decay time for particle x and t2 is of particle y. The decay time of xy is either t3 > t1 or t2 if it gets stable, or t4<t1 or t2 if it becomes more unstable? Is this what you think is happening with toponium, that it is getting more stable as a composite particle? Or you were able to see an even 10-25s small?

Here there is no decay time of toponium because it does not exist. We see the effect of a bound state without having a real one. That's the (quantum field theory) magic behind it.

I hope this clarifies, although I am unsure I have fully answered the questions. Feel free to come back to me where needed.

Wow. Well thanks for the explanation. Let's see of I got this right. So itsince they are created in a pair formation, their initial state is moving away from each other. Also given that the strong force is weak at high energy, the quark and anti-quark don't come close enough.

Well a virtual particle showing it's effects! I mean I never though you can actually feel effects of something that didn't exist. Now what I am going to say may sound naive, but then my understanding of quantum physics is limited to very basics, so do forgive me. How does this magic exist? I mean something that never really existed, how can their effects pop into existence and become measurable? I know, I would need to read up on QFT probably to understand this. But is there a simple explanation that I can read/watch to wrap my head around this, which seems to be blown right now! 😁