- #1

Muh. Fauzi M.

- 18

- 1

## Homework Statement

I have a problem in calculating cross-section in elektron-positron -> muon-antimuon scattering.

## Homework Equations

In the relativistic limit, we find the differential cross-section of {e}+{e^-} -> {μ}+{μ^-} is

\frac{d\sigma}{d\Omega}=\frac{\alpha^2}{4s}*(1+cos^2{\theta}).

When I integrating over \theta, i get an answer:

\sigma=\frac{3*\pi*\alpha^2}{8*s},

but that is not the correct answer. Due to my reference (Halzen and Martin), the answer should be

\sigma=\frac{4*\pi*\alpha^2}{3*s}.

## The Attempt at a Solution

Can someone help me through this problem? My intuition said I have mistaken the integration. But I've tried to re-integral-ing it, still not come up with correct solution.