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Title: Triple collinear emissions in parton showers

Abstract

A framework to include triple collinear splitting functions into parton showers is presented, and the implementation of flavor-changing NLO splitting kernels is discussed as a first application. The correspondence between the Monte-Carlo integration and the analytic computation of NLO DGLAP evolution kernels is made explicit for both timelike and spacelike parton evolution. Numerical simulation results are obtained with two independent implementations of the new algorithm, using the two independent event generation frameworks Pythia and Sherpa.

Authors:
 [1];  [2]
  1. SLAC
  2. Fermilab
Publication Date:
Research Org.:
SLAC National Accelerator Lab., Menlo Park, CA (United States); Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
OSTI Identifier:
1358104
Report Number(s):
SLAC-PUB-16963; FERMILAB-PUB-17-122-T; MCNET-17-05; arXiv:1705.00742
1597573
DOE Contract Number:
AC02-07CH11359
Resource Type:
Journal Article
Resource Relation:
Journal Name: TBD
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS

Citation Formats

Höche, Stefan, and Prestel, Stefan. Triple collinear emissions in parton showers. United States: N. p., 2017. Web.
Höche, Stefan, & Prestel, Stefan. Triple collinear emissions in parton showers. United States.
Höche, Stefan, and Prestel, Stefan. 2017. "Triple collinear emissions in parton showers". United States. doi:. https://www.osti.gov/servlets/purl/1358104.
@article{osti_1358104,
title = {Triple collinear emissions in parton showers},
author = {Höche, Stefan and Prestel, Stefan},
abstractNote = {A framework to include triple collinear splitting functions into parton showers is presented, and the implementation of flavor-changing NLO splitting kernels is discussed as a first application. The correspondence between the Monte-Carlo integration and the analytic computation of NLO DGLAP evolution kernels is made explicit for both timelike and spacelike parton evolution. Numerical simulation results are obtained with two independent implementations of the new algorithm, using the two independent event generation frameworks Pythia and Sherpa.},
doi = {},
journal = {TBD},
number = ,
volume = ,
place = {United States},
year = 2017,
month = 5
}
  • A framework to include triple collinear splitting functions into parton showers is presented, and the implementation of flavor-changing next-to-leading-order (NLO) splitting kernels is discussed as a first application. The correspondence between the Monte Carlo integration and the analytic computation of NLO DGLAP evolution kernels is made explicit for both timelike and spacelike parton evolution. Finally, numerical simulation results are obtained with two independent implementations of the new algorithm, using the two independent event generation frameworks PYTHIA and SHERPA.
  • We investigate the prompt photon photoproduction at HERA within the framework of the k{sub T}-factorization approach to QCD. Our consideration is based on the off-shell matrix elements for the underlying partonic subprocesses and the Kimber-Martin-Ryskin (KMR) unintegrated parton densities in the proton. We also use the Ciafaloni-Catani-Fiorani-Marchesini (CCFM) unintegrated gluon as well as valence and sea quark distributions.
  • We study the fractal scattering patterns of collinear collisions between an electron and a helium ion or a hydrogen atom. We have found that the collisional time plotted against initial energy or initial phase consists of a bi-infinite sequence of cusp-shaped regular intervals interlaced by chaotic bands and repeated enlargements of the chaotic bands show similar patterns. These patterns resemble the previous ones obtained in the retrograde region of the coplanar scattering system, however, the dynamical origin of the self-similar patterns is different and can be understood in terms of various combinations of motions perpendicular and parallel to the Wanniermore » ridge and binary collisions. In particular, we have found that the trajectories near the cusp tips of regular intervals are strongly influenced by a set of triple-collision orbits, trajectories originate and end at the triple-collision point. Using the code and winding number for these orbits, we can organize the fractal scattering patterns into a tree structure. Furthermore, using an ensemble of trajectories with uniformly selected initial phases, we calculate the transition probabilities of excited electronic states from a certain initial state of the hydrogenlike ion or atom using the quasiclassical trajectory method. These transition probabilities illustrate that chaotic regions on the average correspond to higher electronic excitation than that corresponding to the regular regions. {copyright} {ital 1996 The American Physical Society.}« less