Speaker
Description
Among NLO matching methods, the KrkNLO method is unique in exploiting a modification of the PDF factorisation scheme to allow NLO accuracy to be achieved by a multiplicative reweight. This gives positive weights by construction, since it does not use subtraction, and unlike other matching methods has no dependence on an unphysical choice of shower-scale or suppression-factor.
We summarise the recent implementation of the method for general colour-singlet processes in Herwig 7, and present results for LHC processes involving the production of massive and massless vector bosons. We will summarise the results of a systematic comparison with MC@NLO, and also review the properties of the Krk scheme among other factorisation schemes proposed as useful alternatives to MSbar, including their positivity properties.