Purity of the single leptons which were used for the dilepton analysis

only single leptons cut applied
double hit rejection
opening angle (theta > 9 degree)
double hit rejection && opening angle (theta > 9 degree)

Open symbols means that only leptons have been remoued from the sample.
Close symbols means that also the tracks have been removed.

Zoom of the upper picture for the interesting region.

Next figure is showing the purity of the leptons which have created given type of pairs before any dileptons cut have been applied:
e+e+
e-e-
e+e-

Looking into the simulation information it is posible to find out, why those tracks are fakes.
77 % of the fake tracks do NOT have a hit in "inner MDC*, 21 % is missing hit in META,
remaining 2 % corresponds to different cases, what is shows schematicaly below for the leptons creating e+e- pairs.

Meanning of the GCommonTrack is following:

dec key

0 ---> kTrackNotSet

1 ---> kSeenInRICHIPU
2 ---> kSeenInOuterMDC
4 ---> kSeenInRICH
8 ---> kSeenInInnerMDC
16 ---> kSeenInTOF
32 ---> kSeenInShower
64 ---> kSeenInMETA

12 ---> kTracklet ---> kSeenInRICH | kSeenInInnerMDC
72 ---> kTrackKick ---> kSeenInInnerMDC | kSeenInMETA
10 ---> kTrackSpline ---> kSeenInInnerMDC | kSeenInOuterMDC
74 ---> kTrackFullHadron ---> kTrackSpline | kSeenInMETA
76 ---> kTrackKickRICH ---> kTrackKick | kSeenInRICH
14 ---> kTrackSplineRICH ---> kTrackSpline | kSeenInRICH
78 ---> kTrackFullLepton ---> kTrackFullHadron | kSeenInRICH

-- GosiaSudol - 08 Dec 2006