HEP Theory Seminar

Formally and practically accurate parton showers

by Silvia Ferrario Ravasio

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 the inevitably employed parton shower generators introduces systematic uncertainties that affect all measurements at colliders.
In this talk, I will discuss the efforts made by the PanScales collaboration to improve the logarithmic accuracy of parton showers. Until recently, this accuracy was limited to the leading logarithms. 
Specifically, I will demonstrate how we can achieve Next-to-Leading Logarithm (NLL) accuracy for processes involving two colored legs, such as color-singlet production, decay, and deep inelastic scattering.
Furthermore, I will explore advancements beyond NLL for observables that are primarily sensitive to soft emissions, such as particle multiplicity and jet vetoes. 
These developments are crucial for refining our understanding of fundamental particle interactions and reducing uncertainties in collider measurements.