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RE: Let quarks be free! (Particle Physics Series – Episode 3C)

in #science7 years ago

Nice post, as usual.

Just a comment (as usual too) :)

This is the first time I heard 'Quantum FlavorDynamic Theory'. Actually, this is a name that is not used anymore (after googling a little but, I have found it). Please trade if for the theory of the electroweak interactions. This sounds much better to my ears :D

Sorry Quarks, you cannot be set free...

Actually two comments: this is why we accelerate the protons to very high energies. There, the quark becomes free as the strong coupling constant is actually not constant but vary with the energy (by virtue of quantum effects).

And a third comment, to come with the coffee: the 'pi-meson' wording is not really used. We prefer to call those guys pions :)

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Oh yes, yes... I totally understand this conversation

:/

Hi @lemouth, thank you for your great comments, as usual :-)

I actually stumbled on the term QFD recently, and I liked it. I chose it on purpose due to the clear categoriation it provides (QED, QFD and QCD). I know from a previous discussion we had, that the recent theoretical progress has made this delimitation void, and that the term electroweak is more representative of our current understanding and models. However, I stick to the old description for now, for clarity purposes, until I find a way to express the new description with the same simplicity (Still, I will add a few words to the post).

we accelerate protons to very high energies
I chose to just mention 'experiments' that led to verify asymptotic freedom without going into the details (If my memory is correct, I think it was proven by studying the scattering of an electron beam). The highest the energies involved, the more loose the quarks appeared... this is consistent with what you are describing.

I also use Pion with my IB students, never Pi-Meson, haha! But here I chose this wording as it reminds the reader that is just discovering this topic via Steemit, that a pion is a Meson without needing him or her to go to the appendix or consult elder posts. yet, it is a good idea to add the name pion in brackets.

I definitely don't like QFD (I cannot even find it has been heavily used in history)... The reaons is that understanding the origins of flavour is one of the big puzzle of our time and we don't have any solution yet, although plenty of proposals for an underlying theory. By reading it like this, it sounds like being a solved problem, which is not. I hope you understand my concerns (this one I will not let it pass).

Also, QED and QCD are special in the sense these are unbroken symmetries. The symmetries are exact. The story is different for the weak interactions.

On different topic, you may like this illustration. Data shows that at small energies, the strong coupling is stronger and stronger (confinement) and at large energies, it is weaker and weaker (asymptotic freedom). :)

...the origins of flavour is one of the big puzzle of our time and we don't have any solution yet...By reading it like this, it sounds like being a solved problem, which is not.

That is a very convincing argument, and it does hit a chord.

There is a fine line between simplification (so that all can understand) and accuracy, and here I agree, I kind of crossed it a little ;-).

Thanks for this excellent remark. I edited the text.

Thanks a lot! :)

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