[Rivet] undocumented behaviour in wfinder/zfinder (bug ?)

[Nicolas Morange]

Hi Frank,

Thanks for your quick answer.
For what I see all the other leptons are removed, for 
LeptonClustersConstituents (which contains the particles that will eventually 
be removed) doesn't know about pT and eta cuts. That seems normal, as only the 
clustered leptons have to pass the cuts.

As a quick&dirty workaround I'm trying to merge :
zfinder.remainingFinalState()
+ zfinder.getProjection<FinalState>("LeptonClusters")
- zfinder.constituentsFinalState()
which adds the composite clustered leptons to the final state.
that's not completely correct but that should do a decent job.

Cheers,
Nicolas

Le Vendredi 29 Juillet 2011 19:30:41 Frank Siegert a écrit :
> Hi Nicolas,
> 
> I'm afraid you are right, there is an inconsistency. It is not removing
> all leptons though, but "only" the ones which pass the initial lepton
> cuts. But that's still more than the ones used as Z, and thus wrong.
> 
> It's not obvious to me how to solve this with the current approach of
> chaining existing projections (LeptonClusters and InvMassFinalState in
> this case). I would need to be able to access the original particles
> which form the two LeptonClusters accepted by IMFS. So there doesn't
> seem to be a way around duplicating LC and IMFS into a combined
> projection, which might as well be the ZFinder then.
> 
> I'll think about this for an hour and if I (or anybody else on this
> list) haven't come up with a better solution by then, I'll start working
> on it.
> 
> Cheers,
> Frank
> 
> On 29/07/11 16:46, Andy Buckley wrote:
> > Hi Nicholas,
> > 
> > I'm a bit uncertain about exactly how the remainingFS works for WFinder
> > and ZFinder... hopefully someone can clarify and check that there is no
> > bug: Frank S, can you help?
> > 
> > We're just about to make a new Rivet release, and I just uploaded the
> > release tarballs to the HepForge downloads area... but I'll wait for
> > confirmation that there's not a bug before making the release official.
> > 
> > Cheers,
> > Andy
> > 
> > On 29/07/11 15:29, Nicolas Morange wrote:
> >> Hello,
> >> 
> >> I'm writing a Z+jets analysis.
> >> Thus I use a ZFinder whose remainingFinalState() is chained to a
> >> FastJet. However, the code in ZFinder
> >> 
> >> 00044 LeptonClusters leptons(fs, bareleptons, dRmax,
> >> 00045 clusterPhotons, excludePhotonsFromRFS,
> >> 00046 etaRanges, pTmin);
> >> 00047 addProjection(leptons, "LeptonClusters");
> >> 00048 InvMassFinalState imfs(leptons, std::make_pair(pid, -pid),
> >> m2_min,
> >> m2_max);
> >> 00049 addProjection(imfs, "IMFS");
> >> 00050
> >> 00051 VetoedFinalState remainingFS;
> >> 00052
> >> remainingFS.addVetoOnThisFinalState(leptons.constituentsFinalState());
> >> 00053 addProjection(remainingFS, "RFS");
> >> 
> >> gives me the impression that not only the Z leptons are removed from
> >> the
> >> remainingFS, but also the other leptons in the event.
> >> Is this correct ?
> >> And how should I do to remove only the Z leptons (and associated
> >> photons) from
> >> the final state ?
> >> 
> >> Cheers,
> >> Nicolas
> >> _______________________________________________
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> >> Rivet at projects.hepforge.org
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