Increasing the accuracy of Parton Showers for hadron colliders

by Silvia Ferrario Ravasio (CERN)

Friday 17 Feb 2023, 14:00 → 16:00 Europe/Zurich

4/3-006 - TH Conference Room (CERN)

Shower Monte Carlo generators simulate fully exclusive collider events, and are essential tools for the interpretation of much of the data from the LHC and its predecessors.  Their core is represented by Parton Shower (PS) algorithms, which provide the inclusion of soft radiation and enable us to mimic a realistic high-multiplicity collider event. The flexibility of these tools comes at a cost of a lower accuracy, which can lead to large systematic uncertainties and compromise the physics potential of the LHC and future colliders. In this talk I will discuss the criteria introduced by the PanScales collaboration to assess the logarithmic accuracy of PS's. In particular, I will focus on the constraints that an angular-ordered PS needs to satisfy to retain next-to-leading-logarithmic (NLL) accuracy for global observables, presenting Herwig7 predictions for lepton collisions and Drell Yan. I will also show new results for the PanScales dipole showers, which represent the first family of showers with demonstrated NLL accuracy for Drell-Yan and gluon-fusion production at hadron colliders, for both global and non-global observables.

CERN.pdf