PASS1 Rejection Check
 
 
Cut 1998 Rej. ( inverted) 2002 Rej.  2002 Acc.
Trigger bit 1.01 - -
RD_TRK 1.00 1.00 1.00
STLAY 1.05 1.30,1.15,1.11,1.08  a)+b) 0.8, 0.82 g)
RSHEX 1.01 1.38 -> 1.01 a) 0.92
TRKTIM 1.06 1.00 1.0
INTIM 1.10 - -
FITPI 4.00 -> 2.22  1.25 c) 0.65
UTC 1.14 1.18,1.25 d) 0.94 h)
RDUTM 1.00 1.01 f) 0.99
Range1  1.00 - -
PDC 1.11 1.11,1.15 0.75
LAY14 1.03 1.03,1.02 1.0
Target No record -

The total pass1 rejection is about 1.8 (see the rejection as a function of run)

Problems:

a) L1.2 screwup until run 48070
b) Online stopping counter at 20 and 21, failure of offline stopping counter determination due to the noise with low energy  and one-end timing.
d) UTC and PDC rejection anomaly from run 49278 to 49751 due to the change in the IC CFD width (from 30 nsec to 10 nsec)
c) Loose FITPI4 is in use in order to main a high acceptance and low rejetion in pass1
f) UTC and RDUTM are totall correlated because the UTC track is required to match the T.2 hit.
g) This number is still for the old STLAY cut. Modification to the range routine has not been implemented yet.
h) The number should not be interpreted as the UTC acceptance, because about 50% of the loss here is actually due to the problem of matching between UTC and RS.
 
 

Investigation of events with PTOT=0
 
 
Condition Events Ratio
No requirement 1758 --
Good UTC and target 1067 1067/1758=60.7%
Bad UTC but good target  11 11/1758=0.6%
Good UTC but bad target 389 389/1758=22.1% a)
Bad UTC and/or bad target 291 291/1758=16.6% b)

Problems:

a) Swathccd fails to find a cluster of pion or kaon fibers. PTOT is re-computed without contribution from target.
b) The UTC track out off the angle window allowed by the hit T.2.\
 

Investigation of the events fail the STLAY cut
 

0)Cuts applied: track quality, online PV, LHEX, L1.2 and BOX cuts.
1)The STLAY cut is used to reject events having a difference in the online (TLAY) and the offline (LAYV4) stopping counter.
2)Using piscat monitor sample with proper setup cuts, the acceptance loss is estimated for each circumstance.
Cut PNN1 box PNN2 box
Before old STLAY 6486 11281
After old STLAY 6218  (95.87%)  10558 (93.59%)
TLAY=20 25       ( 0.38%) 45        (  0.40%)
TLAY=21 46       ( 0.71%) 50        (  0.44%)
LAYV4-TLAY=1 76       ( 1.17%) 114      (  1.01%)
New STLAY     ~97.74%    ~95.11%
3) Bypassing the TLAY cut on L20 and L21, the acceptance loss can be recovered.
4) Modifying the range routine, remove the hit with small energy deposit and only one-end timing. The events with LAYV4-TLAY=1 can be mostly (about 2/3) recovered.