A simple Born-form approximation for e+e-→W+W- at one loop

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, S-I((-)) (s, t) and S-Q((+/-)) (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-. (C) 1998 Published by Elsevier Science B.V.