Abstract
We show how a careful analysis of the behaviour of a parton shower Monte Carlo in the vicinity of the soft and collinear regions allows one to formulate a modified MC@NLO-matching prescription that reduces the number of negative-weight events with respect to that stemming from the standard MC@NLO procedure. As a first practical application of such a prescription, that we dub MC@NLO-∆, we have implemented it in the MadGraph5_aMC@NLO framework, by employing the Pythia8 Monte Carlo. We present selected MC@NLO-∆ results at the 13 TeV LHC, and compare them with MC@NLO ones. We find that the former predictions are consistent with the latter ones within the typical matching systematics, and that the reduction of negative-weight events is significant.
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Frederix, R., Frixione, S., Prestel, S. et al. On the reduction of negative weights in MC@NLO-type matching procedures. J. High Energ. Phys. 2020, 238 (2020). https://doi.org/10.1007/JHEP07(2020)238
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DOI: https://doi.org/10.1007/JHEP07(2020)238