What happens when a neutral pion decays?

[mrcotton]

The neutral phi meson decays to make two photons after around 8 x10-17 seconds
Is this just straight annihilation of the quark anti quark pair?
If it is this does it take this amount of time due the quark colour, as in do you need a red up and a red anti up for annihilation?
Or does this notation I have seen that says (up anti up - down anti down)/√2 mean that the quarks are changing type?
Or are they spiralling around each other in the same way that positronium is stable for 125 pic seconds?
Thanks for any help on this
Mr C

 

[Bill_K]

The neutral phi meson decays to make two photons after around 8 x10-17 seconds
Or does this notation I have seen that says (up anti up - down anti down)/√2 mean that the quarks are changing type?

Did you mean to say the neutral pion? According to Wikipedia the phi meson decays in 10^-22 sec

 

[mrcotton]

Hi Bill_k
it was the neutral pion I meant. It the idea that it is made from an up anti up that has got me thinking about this