Dr. Alexander Karlberg

Parton shower event generators are essential tools for establishing the quantitative connection between theory and experiment. However, their flexibility comes with a trade-off: they generally offer lower formal accuracy compared to state-of-the-art analytic calculations, which in turn have more limited applicability. The poor accuracy of parton shower generators introduces systematic uncertainties that affect all measurements at colliders, and it is therefore crucial that we improve their accuracy. In this talk, I will first give a general introduction to parton showers. I will then proceed to talk about recent work on advancing the PanScales parton showers to NNLL and NLO accuracy. For the latter I will introduce a new matching scheme, ESME, which is positive definite by construction.