# Pion desintegration

1. Aug 29, 2010

### atomqwerty

1. The problem statement, all variables and given/known data
A pion that is moving at 0.98c, desintegrates producing two photons that form both of them the same angle with the direction of the initial pion. Find the angle and the enrgy for the photons. (Pion mass: 135 Mev/c2)

2. Relevant equations

E = K + m0c2

3. The attempt at a solution

I've found that the energy for the pion is 678,4 Mev. Now if I apply the conservation of energy, (or conservation of momentun), I'm confused, because a photon has no mass, right?

Thanks

2. Aug 29, 2010

### Vanadium 50

Staff Emeritus
Why do you think that equation is relevant? (It's true - but why is it relevant?)

3. Aug 29, 2010

### atomqwerty

I think that provides the expressionn for the energy for each particle, that wiould be necessary for the conservation of energy. Is that correct?

4. Aug 29, 2010

### Vanadium 50

Staff Emeritus
It's not relevant.

What other equations have you been studying recently?

5. Aug 29, 2010

### atomqwerty

relativistic momentum p = γm0v

Kinetic energy K = m0c22-1)

Equation energy - momentum E2-(cp)2 = (m0c2)2

and I think that's all

6. Aug 31, 2010

### Vanadium 50

Staff Emeritus
OK, so which of these might help?

7. Aug 31, 2010

### atomqwerty

Uhm, maybe Equation energy - momentum? Ut can be a problem to be solved with the conservation of momentum/energy...

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