[Rivet] ZFinder problem report

[Judith Katzy]

Hi Andy,

our understanding was that the ClusterPhoton flag only refers to the  
final state output, not the Zpt reconstruction. In order to avoid any  
interpretation issues it would be best to
write 1-2 sentence documentation on what this is supposed to do.

The analysis code is in the usual analysis area on lxplus since Elena  
didn't have submission rights to svn.

I strongly suggest that we should keep all the 3 types of corrections  
that ATLAS provides in hepdata and that are programmed in the current  
version.

best regards,
Judith


On 10 Sep 2011, at 16:37, Andy Buckley wrote:

> 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
>
> The University of Edinburgh is a charitable body, registered in
> Scotland, with registration number SC005336.
>