# Differential Cross Section

ian2012
What is physically meant by:

$$\frac{d \sigma}{d \Omega}$$

Where $$\sigma$$ is the cross section and $$\Omega$$ is solid angle.
I can't really picture it.

## Answers and Replies

kulmalukko
Differential cross section $$\frac{d\sigma}{d\Omega}$$ tells you what is the probability that a particle decay with a certain solid angle.

If you multiply $$d\sigma/d\Omega$$ by the incident flux (number of particles per unit area) and by a small solid angle $$\Delta\omega$$, that gives the number of particles scattered into that solid angle.