Herwig++ 2.6 Release Note
K. Arnold, L. d'Errico, S. Gieseke, D. Grellscheid, K. Hamilton, A. Papaefstathiou, S. Platzer, P. Richardson, C. Rohr, A. Schofield, A. Siodmok, M. Stoll, D. Winn
TL;DR
This paper introduces Herwig++ 2.6, a major release that extends hadron-hadron simulations with integrated NLO capabilities, advanced parton showers, and expanded BSM modeling. Key contributions include the Matchbox NLO framework with automated dipole subtraction and choices of POWHEG or MC@NLO matching, plus MLM merging of AlpGen-generated events. Other advances cover a coherent dipole shower, a statistical colour-reconnection model, wide-angle gluon radiation, and an energy-extrapolation scheme for underlying-event tunes, as well as new BSM scenarios such as a color sextet diquark and Z' models. Together, these updates enhance predictive power for LHC phenomenology and lay groundwork for the 3.0 release and migration away from the FORTRAN predecessor.
Abstract
A new release of the Monte Carlo event generator Herwig++ (version 2.6) is now available. This version comes with a number of improvements including: a new structure for the implementation of next-to-leading order matrix elements; an improved treatment of wide-angle gluon radiation; new hard-coded next-to-leading order matrix elements for deep inelastic scattering and weak vector boson fusion; additional models of physics beyond the Standard Model, including the production of colour sextet particles; a statistical colour reconnection model; automated energy scaling of underlying-event tunes.