Matching Beyond Fixed Orders

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'''Interested parties''': ''Piergiulio Lenzi, Vitaliano Ciulli, Peter Skands, Leif Lonnblad, Simon Platzer, Jon Butterworth, Jeppe Anderson, Mario Campanelli, Markus Warsinsky, Matthew Schwartz, Peter Loch, Dieter Zeppenfeld, Giacinto Piacquadio, Paulo Francovilla +...''
'''Interested parties''': ''Piergiulio Lenzi, Vitaliano Ciulli, Peter Skands, Leif Lonnblad, Simon Platzer, Jon Butterworth, Jeppe Anderson, Mario Campanelli, Markus Warsinsky, Matthew Schwartz, Peter Loch, Dieter Zeppenfeld, Giacinto Piacquadio, Paulo Francovilla +...''
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== Chart the problem. Determine some Classic Examples ==
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== Matching in the high energy limit ==
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== Tuning in the presence of matching ==
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=== Chart the problem. Determine some Classic Examples ===
[http://www.slac.stanford.edu/spires/find/hep/www?eprint=arXiv:0903.3918 Effect of ME corrections] on low pT end of the Z pT distribution compared for PYTHIA, HERWIG, Sherpa, Alpgen. Some points:
[http://www.slac.stanford.edu/spires/find/hep/www?eprint=arXiv:0903.3918 Effect of ME corrections] on low pT end of the Z pT distribution compared for PYTHIA, HERWIG, Sherpa, Alpgen. Some points:
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PL slide to be linked here.
PL slide to be linked here.
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== Influence of UE on matching and vice versa ==
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== How would low x logs/high energy limit affect tunes? ==
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How would low x logs affect tunes?
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Expect extra events at with high rapidity jets due to:
Expect extra events at with high rapidity jets due to:

Revision as of 13:32, 13 June 2009

Interested parties: Piergiulio Lenzi, Vitaliano Ciulli, Peter Skands, Leif Lonnblad, Simon Platzer, Jon Butterworth, Jeppe Anderson, Mario Campanelli, Markus Warsinsky, Matthew Schwartz, Peter Loch, Dieter Zeppenfeld, Giacinto Piacquadio, Paulo Francovilla +...

Contents

Matching in the high energy limit

Tuning in the presence of matching

Chart the problem. Determine some Classic Examples

Effect of ME corrections on low pT end of the Z pT distribution compared for PYTHIA, HERWIG, Sherpa, Alpgen. Some points:

  • Affect n=1 ME corrections, Pythia, Herwig, Alpgen+Herwig and Sherpa all pretty much agree. For Algen+Pythia there is a significant difference at low pT. Means that PYTHIA tune would be different for usage with & without Alpgen.

PL slide to be linked here.

How would low x logs/high energy limit affect tunes?

Expect extra events at with high rapidity jets due to:

  • large colour singlet contribution. This will have a component with rapidity gaps, and a component where these gaps have been destroyed by UE.
  • large colour octet contribution enhanced by low x logs (Jeppes's calculations).

Presumably these effects will distort min bias tunes etc, since this physics is not necessarily in the MC. The first effect actually can be modelled by HERWIG+JIMMY, to some extent at least.


Not addressed:

  • How dependent on matching strategy?
  • Are there ways of revamping pre-matched tunes?
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