# Pion decay and photon frequencies

1. Oct 13, 2009

### snc1318

1. The problem statement, all variables and given/known data

we are given a neutral pion moving at 0.98c straight in the x-direction. The pions rest mass is 135MeV/c^2. two photons are emitted in opposite direction parallel to the pion's motion.

I need to find the two frequencies of each photon.

2. Relevant equations

m=0, E=p*c
conservation of Energy E^2=(c*p)^2+(m*c^2)^2
gamma=1/sqrt(1-Beta^2)
Beta = v/c
p=gamma*m*v
E=gamma*m*c^2

3. The attempt at a solution

i know that energy and momentum are conserved but i dont know exactly what i am meant to do with the momentum relation of each pion. i keep trying all different tactics but keep going in circles. i feel like im missing something really obvious.

2. Oct 13, 2009

### kuruman

If you don't show what you have done, we cannot diagnose where you went wrong. You have two equations (momentum and energy conservation) and two unknown photon frequencies. Begin by writing

Pbefore=Pafter
Ebefore=Eafter