Veto cut efficiency analysis.
To estimate a veto efficiency cut data from the second snake scan was analyzed.
Veto to Hycal type of matching.
A veto counter response was determined by signals from both, top and bottom veto PMT. A time interval
between the signals should be Δt < 25 n, |t1 + t2|/2 - t(hycal)< 15 ns.
Prim_ana uses several types of Veto to HyCal matching according to: reconstructed x of the HyCal cluster with Veto
counter x match, reconstructed y of the HyCal cluster with Y reconstructed by Veto match, time difference between
Veto and Hycal events.
Two runs were taken to study these matching types and overall veto response. One run is a scan of a single row from a
lead glass top panel, the second run is a scan of a single row of the crystal region. Results of the veto response by match
type is shown.
Probability to match neutral particle as charged for each veto
counter.
Veto response for crystal regions.
Veto response for each veto counter.
Central region (6x6 HyCal modules) excluded.
Veto response by energy
Tagger energy
N
Hycal energy
N
Veto response by HyCal energy after the cuts.
Cuts:
Ehycal/Etagger - 1 :
±0.09 for crystals,
±0.14 for lead glass
(Both corresponds to 3*ϭ)
Trig photon tdif: -5 to 15
X mean cut: ± 1cm
Y mean cut: ± 1cm
Veto response by Tagger energy.
Veto response in clock trigger events.
Crystal region:
Clock trigger events number : 46071
events with some veto hits: 4
veto to HyCal match: 1
Lead glass:
Clock trigger events number : 94273
Events with some veto hits: 4
Veto to HyCal match: 2
Total:
Clock trigger events number : 140344
Events with some veto hits: 8
Veto to HyCal match: 3
Veto response in clock trigger events: 0.002 %
Table of veto response for each HyCal module.
1.1 < E < 1.7, <E> = 1.392 (GeV)
Table of veto response for each HyCal module.
3.8 < E < 5.5, <E> = 4.667 (GeV)
Conclusion
●
●
●
The table of veto cut
efficiency for each HyCal
module is obtained.
Veto cut efficiency energy
dependence is observed.
This study estimates veto
cut efficiency to use it in π0
analysis.