Advanced

Merging parton showers and matrix elements -- back to basics

Lavesson, Nils LU and Lönnblad, Leif LU (2008) In Journal of High Energy Physics 4(85).
Abstract
We make a thorough comparison between different schemes of merging fixed-order tree-level matrix element generators with parton-shower models. We use the most basic benchmark of the O(alpha_S) correction to e+e- -> jets, where the simple kinematics allows us to study in detail the transition between the matrix-element and parton-shower regions. We find that the CKKW-based schemes give a reasonably smooth transition between these regions, although problems may occur if the parton shower used is not ordered in transverse momentum. However, the so-called Pseudo-Shower and MLM schemes turn out to have potentially serious problems due to different scale definitions in different regions of phase space, and due to sensitivity to the details in... (More)
We make a thorough comparison between different schemes of merging fixed-order tree-level matrix element generators with parton-shower models. We use the most basic benchmark of the O(alpha_S) correction to e+e- -> jets, where the simple kinematics allows us to study in detail the transition between the matrix-element and parton-shower regions. We find that the CKKW-based schemes give a reasonably smooth transition between these regions, although problems may occur if the parton shower used is not ordered in transverse momentum. However, the so-called Pseudo-Shower and MLM schemes turn out to have potentially serious problems due to different scale definitions in different regions of phase space, and due to sensitivity to the details in the initial conditions of the parton shower programs used. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Phenomenological Models, Jets, Parton Model, QCD
in
Journal of High Energy Physics
volume
4
issue
85
publisher
Springer
external identifiers
  • wos:000255662900085
  • scopus:44449083999
ISSN
1126-6708
DOI
10.1088/1126-6708/2008/04/085
language
English
LU publication?
yes
id
f13d24e4-5bd0-4a41-b189-d5bf9ba06dd1 (old id 773444)
alternative location
http://arxiv.org/pdf/0712.2966
date added to LUP
2007-12-19 16:53:15
date last changed
2017-01-01 04:50:40
@article{f13d24e4-5bd0-4a41-b189-d5bf9ba06dd1,
  abstract     = {We make a thorough comparison between different schemes of merging fixed-order tree-level matrix element generators with parton-shower models. We use the most basic benchmark of the O(alpha_S) correction to e+e- -> jets, where the simple kinematics allows us to study in detail the transition between the matrix-element and parton-shower regions. We find that the CKKW-based schemes give a reasonably smooth transition between these regions, although problems may occur if the parton shower used is not ordered in transverse momentum. However, the so-called Pseudo-Shower and MLM schemes turn out to have potentially serious problems due to different scale definitions in different regions of phase space, and due to sensitivity to the details in the initial conditions of the parton shower programs used.},
  author       = {Lavesson, Nils and Lönnblad, Leif},
  issn         = {1126-6708},
  keyword      = {Phenomenological Models,Jets,Parton Model,QCD},
  language     = {eng},
  number       = {85},
  publisher    = {Springer},
  series       = {Journal of High Energy Physics},
  title        = {Merging parton showers and matrix elements -- back to basics},
  url          = {http://dx.doi.org/10.1088/1126-6708/2008/04/085},
  volume       = {4},
  year         = {2008},
}