[Rivet] VetoedFinalState problem

Emily Nurse nurse at fnal.gov
Mon Jan 28 22:56:23 GMT 2008


Dear rivet-ers,

I would make a new rivet ticket but I don't think I can (perhaps  
connected to the fact that I don't have wiki write access?)

There seems to be a problem in TotalVisibleMomentum and other  
Projections when used with a VetoedFinalState (ie/ as in  
CDF_2006_S6653332).
TotalVisibleMomentum is created in the analysis constructor with a  
VetoedFinalState as input, but the VetoedFinalState::addVetoPairId()  
methods are not called until later in the analysis constructor so the  
vetoed particles are not actually vetoed in the TotalVisibleMomentum  
calculation. In addition, since VetoedFinalState is copied as a  
FinalState to TotalVisibleMomentum it loses the additional "veto"  
information anyway.

This can be fixed by keeping a VetoedFinalState (instead of  
FinalState) as the private data member, _fsproj, in   
TotalVisibleMomentum and by adding an upDate() function to  
TotalVisibleMomentum that can update this data member if any  
particles are vetoed. Alternatively there could be no FinalState& fsp  
passed into the TotalVisibleMomentum constructor and an init 
(FinalState& fsp) method could be written that HAS to be called in  
the analysis constructor (this stops you doing something wrong by  
accident so may be preferable).

I can put such a fix in to all the Projections where this is a  
potential problem unless people would rather a different solution?

Emily.


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