Electrons Scone (All)  
 
 Simple Cone Algorithm

 N
 -----
 Number of electrons per event.

 Exchange 28-Apr-2003:
 Question (HTD): How do we get so many electrons in an event?  What is the 
    object ID for these guys?
 Answer    (LD): The EM candidates stored in the EMparticleChunk satify very 
    loose criteria. With such loose criteria, these plots are probably more 
    indicative of the quality of CAL data rather than that of the electrons. 
    Moreover, depending on the code to produce the plots, this
    may mix electrons from different algorithms (simple cone, CellNN, "road" 
    method). That probably explains that there seem to be different populations
    in the isolation and EM fraction plots.

 ET
 -----
 Transverse energy (GeV).

 Exchange 28-Apr-2003:
 Question (HTD): How about a better x-scale? Maybe a log plot?
 Answer      (): 
 
 ETA
 -----
 The eta (physics) of electrons.

 Exchange 28-Apr-2003:
 Question (HTD): What accounts for the peak on the +eta side at about 1.5? Or is it
    a deficit on the -eta side?  I'd guess it's a deficit from the projection of the
    rate from the central calorimeter into the EC's.
 Answer    (LD):  It's probably a deficit on the -eta side, but I don't know 
    what could cause it. The explanation probably depends on the type of 
    electron displayed (e.g. road electrons depend on tracking, CellNN might be 
    more sensitive to noise that simple cone).

 PHI
 -----
 The phi of electrons.

 Exchange 28-Apr-2003:
 Question (HTD): What accounts for the variation?
 Answer    (LD): This is most probably a problem with the calorimeter (warm 
    region ?)


 ISO
 -----
 Electrons have isolation less than 0.15. Background is, I suppose flatish out to
 isolation of one or more.

 Exchange 28-Apr-2003:
 Question (HTD): What is this? What should we expect?
 Answer    (LD): I think that electrons from several algorithms are mixed and
    on simple cone has an isolation cut at 0.2 (see the plots for loos and tight
    electrons that are only simple cone electrons I believe). Negative isolation
    is probably due to negative energy cells in the neighborhood of the electron
    (electronic noise). For the same reason the EM fraction can be greater than 1.

 EMF
 -----
 Electromagnetic Fraction.  Electrons will deposit most of their energy in the 
 first few layer of the calorimeter.  These layers have material appropriate 
 for electromagnetic showers, so they are called the "electromagnetic calorimeter".

 Exchange 28-Apr-2003:
 Question (HTD): Are the electrons with low EMF background?
 Answer      (): 

 HMX41
 -----
 H-matrix in 41 dimensions.  The H-matrix value for electrons peaks at around 20.
 This doesn't seem tuned up to well. It doesn't look like we cut on this.

 Exchange 28-Apr-2003:
 Question (HTD): What goes into the 41D H-matrix?
 Answer    (LD): Electrons are on the low HMX41 side. I think HMX41 contains 
   the energy fractions in EM1,2,4 and cells in EM3, plus log(ET) and Zvertex.

 HMX9
 -----
 H-matrix in 9 dimensions. It looks like we cut on that at 20.

 Exchange 28-Apr-2003:
 Question (HTD): What goes into the 9D H-matrix?
 Answer    (LD): I thought that only the HMX8 was used (i.e. no preshower).
    electrons are on the low HMX9 side. The HMX9 contains the fractions in EM1 
    to FH1 and the position in EM3.

 
 PHI vs Eta
 ----------
 A two-dimensional distribution. I suppose we are looking for hot spots or 
 dead regions.