Any particle physicists?

[tycoonist]

i have a question based on my recent learning of particle physics:

since the neutral pion (i.e. pi-0) is formed from either an up quark and an anti-up quark or a down and an anti-down quark, wouldn't it annihilate? because i was taught that anti matter annihilated when it met its regular counterpart.

 

[mboettcher]

Thats how its created I believe. In the annihilation. The energy has to go somewhere. IN this case its (at least in part) in the pion (which has been shown to be massless recently I believe?). Anyway I'm not a particle physicist nor would I recommend becoming one for a couple deceades (accelerators aren't at the top of the budget lists during recessions). I'm going to go look this info up to make sure. Be back In an hour or so.

 

[mboettcher]

OK, I'm an idiot and that was a smart question. Anyway wikipedia has a good explanation. Neutral pions are only found in superpositions.

The neutral combinations of up with anti-up and down with anti-down have identical quantum numbers, so they are only found in superpositions

 

[TyrionLannister]

Ok...

So how can I incorporate this into my Civ 4 strategy?

 

[tycoonist]

ah i may have posted this in the wrong forum... can an admin move this to off-topic/science or something? *facepalm*

 

[popejubal]

Ok...

So how can I incorporate this into my Civ 4 strategy?

Amphibious neutral pions are the superior.

Good tacticians create their armies from baryons. Truly great tacticians create their armies from tachyons.

"Where your enemy is strong, be nowhere. Where your enemy is weak, be everywhere." -sounds like a tachyon to me.

 

[SergeiKirov]

I think it's because they're orbiting each other, like electrons around a nucleous (if they weren't they'd just crash into it, and we wouldn't be here talking about them).

P.S. -- Don't take me too seriously, I'm a condensed matter physicist, I have no clue about mesons.

 

[CynicalMagician]

I like that even though this is the civ4 S&T forum, he still got an answer about a sophisticated particle physics question within 6 minutes.

 

[Lord Tirian]

I think it's because they're orbiting each other, like electrons around a nucleous (if they weren't they'd just crash into it, and we wouldn't be here talking about them).

Sort of right - to annihilate, they need to get into interaction range - they need to "touch", figuratively speaking, which takes time. Annihilation isn't instantaneous.

And the annihilation is the exactly reason why they have a lifetime of the order of 10^-17 s (i.e. typical EM decay, they also decay into photons, unlike charged pions), whereas charged pions have lifetimes of the order of 10^-8 s (which is typical for a weak decay). The difference of 9 magnitudes makes relatively clear that they *are* annihilating each other.

Cheers, LT.

 

[dot]

This thread just magnified my love for CFC - again.
Odd question asked in the wrong forum and yet ... He has gotten replies.
And quite some of them.
Gotta love CFC.

 

[mirthadir]

"Met" is a poorly defined term. It actually doesn't take any time for most pions to "touch", it requires that their internal dynamics align and that the strong component be off set by EM concerns. To whit there are forces pulling the particles "togethor" to annihilation and others balancing them apart, most of the time pions form and instanteously annhilate (so called virtual particles) much more rarely things work out to stabilize them for a short bit of time and you get some very fun interplay between electro-weak and strong forces. Eventually the waves align and the whole mess goes poof (or crashes into something else), but in theory with enough strong force properly applied you could build an eternal pion.

 

[kolhite]

Amphibious neutral pions are the superior.

Good tacticians create their armies from baryons. Truly great tacticians create their armies from tachyons.

"Where your enemy is strong, be nowhere. Where your enemy is weak, be everywhere." -sounds like a tachyon to me.

that made me laugh, really. That's fine parody.

 

[§L¥ Gµ¥]

Amphibious neutral pions are the superior.

Good tacticians create their armies from baryons. Truly great tacticians create their armies from tachyons.

"Where your enemy is strong, be nowhere. Where your enemy is weak, be everywhere." -sounds like a tachyon to me.

haha, well done, nice take on Sun Tzu too!