[Rivet] ZFinder problem report

[Andy Buckley]

On 10/09/11 01:51, Yatsenko, Elena wrote:
> Hi Andy,
>
> I'm sorry that I didn't reply, it seems like I missed this mail.
> In ZpT analysis we are considering only 4 momentum of the Z boson and we expect that clusterPhotons flag shouldn't affect on this momentum.
> But during analysis we saw that it changes the momentum of Z boson in the case when we apply dR=0.1 cut.
> And it seems like when clusterPhotons =<false>  ZFinder takes Z bosons with decay to "bare" leptons by default.

Thanks for the clarification :) However, that is exactly what I *expect* 
it to do! The Z boson that is returned is constructed from the effective 
lepton momenta, which depend on whether or not the photons around them 
are being clustered.

In Rivet the "Z" is the reconstructed object, because if it were 
anything else the output would be generator dependent -- or at best 
require a correct guess at the graph structure being used to represent 
the hard process. Maybe we should make that more clear in the documentation.

Can you add your analysis code to the ATLAS tuning SVN and I'll 
cross-check it? If you're happy with it (code style matching the 
convention, etc., as well as functionally as intended), you can also 
send it to us directly and we'll get it into Rivet 1.6.1.

Cheers,
Andy

-- 
Dr Andy Buckley
SUPA Advanced Research Fellow
Particle Physics Experiment Group, University of Edinburgh

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