= Forward-backward asymmetry
{title2=$A_{\rm FB}=(\sigma_F-\sigma_B)/(\sigma_F+\sigma_B)$}
The normalized difference of forward and backward <cross sections> relative to a specified incoming-particle axis. For $d\sigma/dc=K[(A+B)(1+c^2)+2(A-B)c]$ with $c=\cos\theta$, integration gives $\sigma_F-\sigma_B=2K(A-B)$ and $\sigma_F+\sigma_B=8K(A+B)/3$, hence $A_{\rm FB}=3(A-B)/(4(A+B))$. The <pole forward-backward asymmetry for charged leptons> is its specialized <Z boson> result.
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