The orderαs2 contribution to theK-factor of the Drell-Yan process

Abstract

We present a complete orderαs2 calculation of theK-factor in the Drell-Yan process. All contributions due to soft and virtual gluons have been taken into account. Our findings are that the abelian (CF) part of theK-factor exponentiates almost exactly (numerically). The deviation of the exponentiation is therefore wholly due the non-abelian part. In theMS¯ scheme for the renormalized coupling constant the correction with respect to the zeroth order contribution at Q2=100 GeV2 (ΛMS¯=0.3 GeV) is about 62%. At Q2=MZ2 this reduces to about 18%. Its implication for massive muon pair production at fixed target experiments and electroweak vector boson production in collider experiments is discussed.