# Particle Collision

## Homework Statement

The results of particle collisions are observed using particle detectors. Sometimes the products of these collisions are themselves unstable and decay to give further particles; the products of decay can be photons.

In one collision, a stationary $\pi^\circ$ meson is produced which then decays to give two gamma ray photons. The rest mass of the meson is $135 \ MeV/c^2$.

$\pi ^\circ \rightarrow \beta + \beta$​

Calculate the wavelength of each photon.

## Homework Equations

$E = hf = \frac{hc}{\lambda}$

## The Attempt at a Solution

How can I find $E$? I can carry on from that point but I don't know which equation to use to find $E$?

Last edited: