# Reletivistic particle decay

1. Oct 5, 2008

### mt948434

hello everybody I am new too these forums and am looking for a little help on a problem. I don't want anyone to give me the answer so i will just post the basic question and any help would be appreciated.

If an uncharged meson decays into two charged pions in the presence of a magnetic field. If the mass of a pion, magnitude of the magnetic field and the radius of the pions path are all known, I need to find the pions momenta and speed, as well as the mass of the meson.

thanks for any help!

2. Oct 5, 2008

### clem

1. There is a formula for the pion's momentum in terms of the radius and B.
2. Given the pion momentum, and knowing its mass, use the formula for the pion energy.
3. From p and E, you can find the pion velocity.
4. To get the meson's mass, you have to know the original angle between the two pions momenta. Then use $$M^2=(E_1+E_2)^2-({\vec p}_1+{\vec p}_2)^2$$.

3. Oct 5, 2008