Event generators: New developments.

After an introduction to event generators we give an overview of developments in the field of joining matrix elements with parton showers. Starting with matrix element corrections, we also discuss implementations that match LO and NLO matrix elements with parton shower results correctly. Finally, the new Monte Carlo program Herwig++ is described. We report on its status of development and some major physics improvements.Comment: 12 pages, 11 Figs, invited talk at the 14th Topical Conference on Hadron Collider Physics (HCP2002), Karlsruhe, Germany, 30 Sep--4 Oct 2002, to appear in the proceeding

The new Monte Carlo Event Generator Herwig++

We present results obtained with the new Monte Carlo event generator Herwig++. In its first version (1.0), Herwig++ is capable of simulating e+e- Annihilation events. We compare results for different distributions with a vast amount of available data from e+e- annihilation.Comment: Proceedings of the XIIth International Workshop on Deep Inelastic Scattering (DIS04), Strbske Pleso, Slovakia, April 14-18 200

Baryon production from cluster hadronization

We present an extension to the colour reconnection model in the Monte-Carlo event generator Herwig to account for the production of baryons and compare it to a series of observables for soft physics. The new model is able to improve the description of charged-particle mutliplicities and hadron flavour observables in pp collisionsComment: 13 pages; v3: updated to match journal versio

NLO corrections to the photon impact factor.

We review the program of the calculation of next-to-leading order corrections to the virtual photon impact factor. Following a brief introduction we present some technical aspects for the various contributions. Recently obtained results for transversely polarised virtual photons are discussed and an outline of how infrared divergences are cancelled is given. Implications of the subtraction of leading energy logarithms are discussed

The Underlying Event in Herwig++

We review the modelling of multiple interactions in the event generator Herwig++ and study implications of recent tuning efforts to LHC data. A crucial ingredient to a successful description of minimum-bias and underlying-event observables is a model for colour reconnection. Improvements to this model, inspired by statistical physics, are presented.Comment: 4 pages, 3 figures. Contribution to the DIS 2012 proceeding