A simple Born-form approximation for e+e− → W+W− at one loop Original Research Article

A simple Born-form approximation at the one-loop level for e+e− → W+W− at high energies is given in analytic form. The different contributions to the three invariant one-loop amplitudes, SI(−) (s, t) and SQ(±) (s, t), determining the Born-form helicity amplitudes are thoroughly investigated analytically and numerically. At energies above 500 GeV, the accuracy of the simple Born-form approximation for the differential production cross section is better than 1% for almost all W+W− production angles, independently of whether the W+W− polarization is summed over, or whether a longitudinal or a transverse polarization is selected for both the W+ and the W−.