Aims and Scope

This workshop aims to gather theorists and experimentalists working in the fields of QCD jets, jet (sub)structure, and parton-to-hadron fragmentation.

The current state of the art and open questions will be surveyed, and put in the context of the potential for decisive new measurements offered by the extremely high statistics and clean environment of future e+e- colliders. 

The workshop forms part of the FCC-ee WG5: QCD & gamma-gamma physics, and follows on from a Workshop on precision alphaS determinations held in late 2015. The combined output from these two workshops will be used to inform a Yellow Report scheduled for 2017. To facilitate this, contributors will be asked to provide brief summaries in a proceedings-style writeup.

The table below, from arXiv:1602.05043, summarises key expected luminosities, running times, and event numbers, at the various FCC-ee CM energies:

Topics for discussion at this workshop include:

• How are the current limitations in precision e⁺e^- constraints affecting theoretical studies, such as:

  • Fragmentation-function determinations

  • Validations of jet substructure techniques

  • Quark-gluon jet discrimination methods

  • Hadronisation corrections.  

• Interplay with hadron colliders from LHC to FCC-hh. Precision modelling of LHC fragmentation corrections currently benefits vitally from the legacy of e+e- colliders. What is the set of FCC-ee measurements that will be most crucial to inform the next-generation fragmentation models for the FCC-hh, especially in light of new questions raised by LHC? 

• What decisive new measurements become possible with the huge jet statistics accessible at an FCC-ee with 10¹² Z's at sqrt(s)=m_Z; 10⁸ W's at sqrt(s)=m_WW; and 10⁶ Higgs bosons at sqrt(s)=240 GeV

• What are the systematic errors that the FCC-ee detectors should target in order to match the expected statistical precision, or where that is not possible, what are the important theoretical targets that should be met or exceeded?

• What fiducial coverage, resolutions, and detector capabilities (such as particle ID) will be required to fully exploit the potential for QCD measurements? 

• Interplay with the rest of the FCC-ee precision program. What are the most crucial QCD measurements / uncertainties / constraints ? What improvements will be most crucial to reach the desired accuracies?

• What is the current size of the theoretical uncertainties: missing higher orders, electroweak corrections, power corrections, hadronization corrections,... ?

• What is the expected .... uncertainty in ~10 years from now: theoretical developments, plus O(1 ab^-1) p-p at 14 TeV at the LHC ?

Organisers:

Peter Skands (chair), David d'Enterria