Differential Cross Section
To leading order, the spin-averaged differential cross section for this process is
- where s,t, and u are the Mandelstam variables, is the fine-structure constant, and is the scattering angle.
This cross section is calculated neglecting the electron mass relative to the collision energy and including only the contribution from photon exchange. This is a valid approximation at collision energies small compared to the mass scale of the Z boson, about 91 GeV; for energies not too small compared to this mass, the contribution from Z boson exchange also becomes important.
Read more about this topic: Bhabha Scattering
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