Initial state radiation in the Herwig 7 angular-ordered parton shower

We study the simulation of initial-state radiation in angular-ordered parton showers in order to investigate how different interpretations of the ordering variable affect the logarithmic accuracy of such showers. This also enables us to implement a recoil scheme which is consistent between final-state and initial-state radiation. We present optimal values of the strong coupling and intrinsic transverse momentum to be used in each version of the parton shower, tuned using Z(0)-boson production at the LHC at 7 TeV. With these tuned showers, we perform a phenomenological study of the Drell-Yan process at several centre-of-mass energies.

Automated summary

We have studied the simulation of initial-state radiation in angular-ordered parton showers and investigated how different interpretations of the ordering variable affect the accuracy of such showers. We also implemented a recoil scheme consistent between final-state and initial-state radiation. By tuning the strong coupling and intrinsic transverse momentum, we presented optimal values for each version of the parton shower and conducted a phenomenological study of the Drell-Yan process at various center-of-mass energies.