The role of W-pair production at future linear colliders.
The W-pair production cross-section is an order more then one for fermion pair creation or any other reactions.This reaction is not only a big background but has to be used as main information channel replacing fermion pairs. The reaction is sensitive to new physics, connected with neutral gauge boson Z', and any modifications of gauge group structure. The analysis of decay product of W may even give us possibilities to make some kind of polarization measurement without polarized initial leptons.
V. V. Gilewsky [[email protected]]
The σ has to fall with energy
To keep σ =const we have to have G1+G2 +1=0;
To have falling σ => G1=1, G2 =-2 (SM value)
For CP-non-invariant form-factors
So, only SM value survive = fine tuning
The case λ+=λ- gives un-polarized cross-section with overall coefficient (1-λ2).
For λ- =-1 and λ+=1 cross-section is defined by only s-channels.
Partial polarization gives all in the middle.