KKMChh: matching CEEX photonic ISR to a QED-corrected parton shower

Abstract

KKMChh adapts the CEEX (Coherent Exclusive Exponentiation) formalism of the Monte Carlo Program KKMC for Z boson production and decay to hadron scattering. Amplitude-level soft photon exponentiation of initial and final state radiation, together with initial-final interference, is matched to a perturbative calculation to second order next-to-leading logarithm, and electroweak corrections to the hard process are included via DIZET. The first release of KKMChh included complete initial state radiation calculated with current quark masses. This version assumes idealized pure-QCD PDFs with negligible QED contamination. Traditional PDFs neglect QED evolution but are not necessarily free of QED influence in the data. QED-corrected PDFs provide a firmer starting point for precision QED work. We describe a new procedure for matching KKMChh's initial state radiation to a QED-corrected PDF, and compare this to earlier approaches.

Presented by S. Yost at ICHEP 2022, Bologna Italy, July 6 - 13, 2022; 6 pages with 3 figures. Update adds a hyperlink to one reference. Now matches the published proceedings version exactly

References in corpus (5)

• The Photon Content of the Proton
• The Monte Carlo Program KKMC for the Lepton or Quark Pair Production at LEP/SLC Energies -- updates of electroweak calculations
• Multi-photon Monte Carlo event generator KKMCee for lepton and quark pair production in lepton colliders
• ISR and IFI in Precision AFB Studies with KKMC-hh
• New Developments in KKMChh: Quark-Level Exponentiated Radiative Corrections and Semi-analytical Results

Cited by in corpus (2)

• On electroweak corrections to neutral current Drell-Yan with the POWHEG BOX
• Overview of IR-Improvement in Precision LHC/FCC Physics