# Born Approximation.

1. Aug 12, 2009

### MathematicalPhysicist

To those who have Cohen-Tannoudji vol 2, QM textbook.
On page 920, he gives there the differential cross section, in equation B-48, which he writes it as:
$$\sigma^{(B)}_k(\theta,\phi)=\frac{\mu^2}{4\hbar^4 \pi^2}|\int d^3 r e^{-iK.r} V(r)|$$
Now shouldn't it be $$\frac{1}{\pi}$$ instead of factor 1/4pi^2?