The goal of the PanScales project is to deepen our understanding, and to improve, the core, parton shower, component of general purpose Monte Carlo event generators, the most widely used theoretical tools in particle physics. Almost every analysis of high-energy collider data relies on simulations with these generators.

The project asks questions such as:

What criteria should we be using to assess the scope and accuracy of parton showers?
What accuracy is achieved by some given class of parton shower?
Can we design parton showers with higher accuracies than is possible today?
What are the phenomenological implications of our understanding of parton showers?

Our hope is that the PanScales project will make it possible to extract more extensive information about the fundamental particles and interactions that make up our universe.

Code

A preliminary release of the code, version 0.2, is now available, which includes NNLL event-shape accuracy for two-body decays.

Key results

The following articles describe some of the core steps in our development of the PanScales family of parton showers and of the tools and calculations for testing them:

arXiv:2409.08316, A collinear shower algorithm for NSL non-singlet fragmentation
arXiv:2406.02661, A new standard for the logarithmic accuracy of parton showers
arXiv:2402.05170, Two-loop anomalous dimensions for small-R jet versus hadronic fragmentation functions
arXiv:2312.13275, Introduction to the PanScales framework, version 0.1
arXiv:2307.15734, Collinear fragmentation at NNLL: generating functionals, groomed correlators and angularities
arXiv:2307.11142, A parton shower with higher-logarithmic accuracy for soft emissions
arXiv:2305.08645, Next-to-leading-logarithmic PanScales showers for Deep Inelastic Scattering and Vector Boson Fusion
arXiv:2301.09645, Matching and event-shape NNDL accuracy in parton showers
arXiv:2212.05076, Lund multiplicity in QCD jets
arXiv:2207.09467, PanScales showers for hadron collisions: all-order validation
arXiv:2205.02861, Lund and Cambridge multiplicities for precision physics
arXiv:2205.02237, PanScales parton showers for hadron collisions: formulation and fixed-order studies
arXiv:2111.01161, Soft spin correlations in final-state parton showers
arXiv:2109.07496, Dissecting the collinear structure of quark splitting at NNLL
arXiv:2103.16526, Spin correlations in final-state parton showers and jet observables
arXiv:2011.10054, Colour and logarithmic accuracy in final-state parton showers
arXiv:2007.10355, Groomed jet mass as a direct probe of collinear parton dynamics
arXiv:2002.11114, Parton showers beyond leading logarithmic accuracy
arXiv:1805.09327, Logarithmic accuracy of parton showers: a fixed-order study
arXiv:1807.04758, The Lund Jet Plane

People

Current members

Melissa van Beekveld (NIKHEF)
Mrinal Dasgupta (University of Manchester)
Basem Kamal El-Menoufi (Monash University)
Silvia Ferrario Ravasio (CERN)
Keith Hamilton (University College London)
Jack Helliwell (Monash University)
Alexander Karlberg (CERN)
Pier Monni (CERN)
Gavin Salam (University of Oxford and All Souls College)
Nicolas Schalch (University of Oxford)
Ludovic Scyboz (Monash University)
Alba Soto Ontoso (Universidad de Granada)
Grégory Soyez (Institut de Physique Théorique, Saclay)
Silvia Zanoli (University of Oxford)

Former members

Funding

Core funding for the project comes from The Royal Society (Royal Society Research Professorship, RSRP\R\231001).

Several other sources have also contributed to specific results, as detailed in individual papers. From October 2018 to September 2024, the research was also funded by the European Research Council (PanScales Advanced Grant, 788223).