Publications (26)
A modified CKKW matrix element merging approach to angular-ordered parton showers
Keith Hamilton, Peter Richardson, Jon Tully
A modified version of the CKKW matrix element merging algorithm is presented, suitable for use in an angular-ordered parton shower, using truncated showers and forced splittings. T…
Introduction to the PanScales framework, version 0.1
Melissa van Beekveld, Mrinal Dasgupta, Basem Kamal El-Menoufi +11
In this article, we document version 0.1 of the PanScales code for parton shower simulations. With the help of a few examples, we discuss basic usage of the code, including tests o…
Finite quark-mass effects in the NNLOPS POWHEG+MiNLO Higgs generator
Keith Hamilton, Paolo Nason, Giulia Zanderighi
We include finite top- and bottom-mass effects in the next-to-next-to-leading order parton shower (NNLOPS) event generator for inclusive Higgs boson production in gluon fusion base…
Practical improvements and merging of POWHEG simulations for vector boson production
Simone Alioli, Keith Hamilton, Emanuele Re
In this article we generalise POWHEG next-to-leading order parton shower (NLOPS) simulations of vector boson production and vector boson production in association with a single jet…
Improving NLO-parton shower matched simulations with higher order matrix elements
Keith Hamilton, Paolo Nason
In recent times the algorithms for the simulation of hadronic collisions have been subject to two substantial improvements: the inclusion, within parton showering, of exact higher…
A Positive-Weight Next-to-Leading Order Monte Carlo Simulation for Higgs Boson Production
Keith Hamilton, Peter Richardson, Jon Tully
In this article we describe simulations of Higgs boson production via the gluon fusion and Higgs-strahlung processes, using the positive weight next-to-leading-order (NLO) matching…
Parton showering with higher-logarithmic accuracy for soft emissions
Silvia Ferrario Ravasio, Keith Hamilton, Alexander Karlberg +3
The accuracy of parton-shower simulations is often a limiting factor in the interpretation of data from high-energy colliders. We present the first formulation of parton showers wi…
Extending the MINLO method
Rikkert Frederix, Keith Hamilton
We consider improving POWHEG+MINLO simulations, so as to also render them NLO accurate in the description of observables receiving contributions from events with lower parton multi…
Merging WW and WW+jet with MINLO
Keith Hamilton, Tom Melia, Pier Francesco Monni +2
We present a simulation program for the production of a pair of W bosons in association with a jet, that can be used in conjunction with general-purpose shower Monte Carlo generato…
Monte Carlo event generators for high energy particle physics event simulation
Andy Buckley, Frank Krauss, Simon Plätzer +40
Monte Carlo event generators (MCEGs) are the indispensable workhorses of particle physics, bridging the gap between theoretical ideas and first-principles calculations on the one h…
NNLOPS simulation of Higgs boson production
Keith Hamilton, Paolo Nason, Emanuele Re +1
We detail a simulation of Higgs boson production via gluon fusion, accurate at next-to-next-to-leading order in the strong coupling, including matching to a parton shower, yielding…
Colour and logarithmic accuracy in final-state parton showers
Keith Hamilton, Rok Medves, Gavin P. Salam +2
Standard dipole parton showers are known to yield incorrect subleading-colour contributions to the leading (double) logarithmic terms for a variety of observables. In this work, co…
Logarithmic accuracy of parton showers: a fixed-order study
Mrinal Dasgupta, Frédéric A. Dreyer, Keith Hamilton +2
We formulate some first fundamental elements of an approach for assessing the logarithmic accuracy of parton-shower algorithms based on two broad criteria: their ability to reprodu…
MINLO: Multi-scale improved NLO
Keith Hamilton, Paolo Nason, Giulia Zanderighi
In the present work we consider the assignment of the factorization and renormalization scales in hadron collider processes with associated jet production, at next-to-leading order…
A Simulation of QCD Radiation in Top Quark Decays
Keith Hamilton, Peter Richardson
In this paper we describe a theoretical framework and algorithms for implementing QCD corrections to top quark decays in the Herwig++ event generator. The dominant corrections, due…
A positive-weight next-to-leading order simulation of weak boson pair production
Keith Hamilton
In this article we describe simulations of ZZ, WZ and WW production based on the positive weight next-to-leading-order matching scheme, Powheg, in the Herwig++ event generator. Bui…
A Positive-Weight Next-to-Leading Order Monte Carlo Simulation of Drell-Yan Vector Boson Production
Keith Hamilton, Peter Richardson, Jon Tully
The positive weight next-to-leading-order (NLO) matching scheme (POWHEG) is applied to Drell-Yan vector boson production in the Herwig++ Monte Carlo event generator. This approach…
A new standard for the logarithmic accuracy of parton showers
Melissa van Beekveld, Mrinal Dasgupta, Basem Kamal El-Menoufi +9
We report on a major milestone in the construction of logarithmically accurate final-state parton showers, achieving next-to-next-to-leading-logarithmic (NNLL) accuracy for the wid…
Parton showers beyond leading logarithmic accuracy
Mrinal Dasgupta, Frédéric A. Dreyer, Keith Hamilton +3
Parton showers are among the most widely used tools in collider physics. Despite their key importance, none so far has been able to demonstrate accuracy beyond a basic level known…
Jet pair production in POWHEG
Simone Alioli, Keith Hamilton, Paolo Nason +2
We present an implementation of the next-to-leading order dijet production process in hadronic collisions in the framework of POWHEG, which is a method to implement NLO calculation…
MINLO t-channel single-top plus jet
Stefano Carrazza, Rikkert Frederix, Keith Hamilton +1
We present a next-to-leading order accurate simulation of t-channel single-top plus jet production matched to parton showers via the POWHEG method. The calculation underlying the s…
Merging H/W/Z + 0 and 1 jet at NLO with no merging scale: a path to parton shower + NNLO matching
Keith Hamilton, Paolo Nason, Carlo Oleari +1
We consider the POWHEG generator for a H/W/Z boson plus one jet, augmented with the recently proposed MiNLO method for the choice of scales and the inclusion of Sudakov form factor…
PanScales showers for hadron collisions: all-order validation
Melissa van Beekveld, Silvia Ferrario Ravasio, Keith Hamilton +4
We carry out extensive tests of the next-to-leading logarithmic (NLL) accuracy of the PanScales parton showers, as introduced recently for colour-singlet production in hadron colli…
Matching and event-shape NNDL accuracy in parton showers
Keith Hamilton, Alexander Karlberg, Gavin P. Salam +2
To explore the interplay of NLO matching and next-to-leading logarithmic (NLL) parton showers, we consider the simplest case of $γ^*$ and Higgs-boson decays to and …
Soft spin correlations in final-state parton showers
Keith Hamilton, Alexander Karlberg, Gavin P. Salam +2
We introduce a simple procedure that resolves the long-standing question of how to account for single-logarithmic spin-correlation effects in parton showers not just in the colline…
Simulation of QED Radiation in Particle decays using the YFS Formalism
Keith Hamilton, Peter Richardson
In this paper we describe a program (SOPHTY) implementing QED corrections to decays in the HERWIG++ event generator. In order to resum the dominant soft emissions to all orders, th…