Logarithmic Accuracy of Angular-Ordered Parton Showers

Abstract

We study the logarithmic accuracy of angular-ordered parton showers by considering the singular limits of multiple emission matrix elements. This allows us to consider different choices for the evolution variable and propose a new choice which has both the correct logarithmic behaviour and improved performance away from the singular regions. In particular the description of $e^{+}{e}^{-}$ event shapes in the non-logarithmic region is significantly improved.