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Action item from PeiZhu (summarized by Maarten) :
1) it would be useful to quote the target luminosity, WW and ZZ cross sections, event selections and selection efficiency
2) since there is the problem of sometimes more than one muon in WW events, it would also be good to remind how the signal muon is defined.
To possible criteria to define the W decay muon when two are present:
- highest momentum
- lowest isolation (sum of particle momenta in a cone around the muon - except the muon itself of course).
This muon is then removed from the particle flow objects list from which Mvis and Mjj is calculated. Hopefully we can get rid of the shoulder in this way.
3) How to quantify the compatibility between the reco mass and the truth mass?
Here the best is to compare things in a consistent way, ie treat the truth record (final state particles only) exactly as the data: apply the same event selections, W decay muon selection, Mvis and Mjj calculation algorithms as for the data. The only difference is to replace the particle flow object list by the truth particle list.
Then remove the W decay muon from the list, and
- calculate Mvis from the rest and compare reco and truth
- apply the same jet clustering algorithm and compare reco and truth
Normally, one should find comparable Mreco/Mtruth ratios in both cases.
4) Finally, it would be useful to make ratio histograms between ud, us, cs, cd (in W) and uu, dd, ss, cc, bb (in Z), in the region of the peaks.
Action item from Bo Li:
1) Try to veto three jets events, in order to reduce the correlation (c_b and c_c).
and try the event selection in page 2 of ALEPH R_b paper below.