RENORMALIZATION SCALE UNCERTAINTY IN THE DIS 2-SECTION(1 JET CROSS)

The deep inelastic scattering 2+1 jet cross-section is a useful observ able for precision tests of QCD, e.g. measuring the strong coupling co nstant alpha(s). A consistent analysis requires a good understanding o f the theoretical uncertainties and one of the fundamental ones in QCD is due to the renormalisation scheme and scale ambiguity. Different m ethods, which have been proposed to resolve the scale ambiguity, are a pplied to the 2+1 jet cross-section and the uncertainty is estimated. It is shown that the uncertainty can be made smaller by choosing the j et definition in a suitable way.