[Rivet] Problem with Rivet LEP Four Jet Analysis

[Andy Buckley]

Simon Plaetzer wrote:
> Dear Rivet developers,
> 
> when running the LEP four jet correlation analysis the Rivet output is 
> not compatible with the builtin Herwig++ analysis. Besides the fact that 
> Rivet seems to use much less events than the Herwig++ analysis selects 
> for the observables, the shape of especially \alpha_{34} is completely 
> different.
> 
> Attached you can find the plots from the Herwig++ analysis and the Rivet 
> analysis, originating from the very same run of 500k events (in this case 
> Herwig++ 2.4.0 and Rivet 1.1.3, both using fastjet 2.4.1).
> 
> The Rivet analysis issues the warnings
> 
> Rivet.Analysis.DELPHI_2003_WUD_03_11: WARN  numdurjets   = 36515
> Rivet.Analysis.DELPHI_2003_WUD_03_11: WARN  numjadejets  = 63975
> Rivet.Analysis.DELPHI_2003_WUD_03_11: WARN  sumofweights = 499960

Hi Simon,

I suspect this has something to do with it:

---
buckley at d18:~$ rivet --show-analysis DELPHI_2003_WUD_03_11

DELPHI_2003_WUD_03_11
=====================

4-jet angular distributions at LEP (note)

Status: UNVALIDATED  <=== !!!
[...]
---

I do remember Hendrik being concerned that he couldn't reproduce some 
observables and suspect he hasn't returned to the analysis since then. 
However, I think this is a good opportunity to sort this out, so have 
set up a tracker ticket:

http://projects.hepforge.org/rivet/trac/ticket/334

Hendrik, can you look into this with Simon's use case?

Andy

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