Muons(All)

 N
 -----
 The number of muons of all kinds.  This includes A-stubs, BC-segments, three
 layer tracks, etc.

 Exchange 29-Apr-2003:
 Question (HTD): How many kinds of muons are there here? How many ways can one muon 
    be counted?
 Answer   (SSR): There are 7 kind of muons (depending on nseg).
    For a detailed description, please have a look at Table 1 of D0note 4091.

 PT
 -----
 The pT (GeV/c) of all muons.  This comes from the tracker if the muon is matched.
 Otherwise it is the local muon pT.  If the local fit was successful, 
 then the global pt is the result of the combination of both measurements 
 (dominated by the tracker measurement of course). 


 ETA
 -----
 Eta of all muons. The boundary of the central muon system is between |eta| of 0.8 
 to 1.0 and is phi-dependent. The reason it is not at a fixed place is that the
 central muon system is rectangular sides of a box-shape. The boundary of the 
 forward muon system is at |eta| of 1.6 to 2.0 for similar reasons. 

 Because physics (as opposed to detector) eta is plotted, the eta shown can be
 larger than the physics eta of the detector.

 PHI
 -----
 Phi of all muons. The periodic spikes are muons plotted at the centers of 
 drift chamber (PDT and MDT) segments.  There are fewer muons found in the 
 plot between 4 < phi< 5, where the acceptance of octants 5 & 6 (bottom) is
 not as good as the rest of the detector.

 CHISQ
 -----
 The chi-sq of the matched central track.  

 Exchange 29-Apr-2003:
 Question (HTD): What is fitted for this chi-sq?
 Answer      (): 

 CHISQLOC
 --------
 The chi-sq of the fit for the muon local track (muon hits only).

 Exchange 29-Apr-2003:
 Question (HTD): Why does this have negative values? Why is the 
    range apparently 0 to 4?
 Answer   (SSR): The default value is -1 (the fit has failed).

 E33
 -----
 The energy deposited in a 3x3 cone in the calorimeter (corresponding to
 delta eta x delta phi of 0.3 x 0.3) centered around the expected position
 the muon enters it.  Muons deposit between 1 and  2.5+ GeV in the 
 calorimeter depending on the angle it goes through. 

 Exchange 30-Apr-2003
 Comment   (FD): That's an undebugged (and not used) variable. This quantity 
    is attached to central tracks (not filled for non-matched muon).


 HALO
 -----
 The energy in a ring of inner radius 3x3 and outer radius 5x5 around the muon.
 This helps determine muon isolation. 
 
 W HITS A
 --------
 The number of PDT and/or MDT hits in the A-layer. Most of
 the A-layer has 4 decks. The central bottom has 3 decks.
 Parts of octant 5 & 6 have no A-layer coverage at all.

 Exchange 29-Apr-2003:
 Question (HTD): Is this hits or decks?
 Answer   (SSR): Hits.

 W HITS BC
 ---------
 The number of PDT and/or MDT hits in the B and C layers, summed.
 These chambers have 3 decks. The peak at zero is A-stubs.
 
 SCINT HITS A
 ------------
 The number of A-layer scintillator hits.

 SCINT HITS BC
 -------------
 The number of B + C layer scintillator hits. The central has,
 except in some special places, only one b or C layer of 
 scintillator.  The forward muon system usually has both.