P0D reconstruction/analysis update

1
P0D reconstruction/analysis update

• LE PHUOC TRUNG

2
Software activities

• A new stable release of nd280 for TPC test beam
• MDC0 status waiting to access the MC datasets
• P0D software
• Continued reconstruction work improve ?0 purity,
  working on improving ?0 reconstruction.
• Electron neutrino reconstruction wait for
  kinematics files from H. Tanaka.
• Testing the midas (electronics output format) to
  root converter.
• Prepare software for cosmic data processing
  reconstruction, calibration constant calculation.

3
Muon decay tagging update
58 ns
Beam
After spill
100 ns
MUON DECAY TAGGING
CC ? interaction, ?- not reconstructed
P0D
xz or yz
Later bunches
After spill
Clustering seed

• Expand clustering seed into later hits, hits
  added to the cluster are decay hits
• Make sure decay hits are distance connected 9cm,
  time connected 20ns
• Event with 2 or more decay hits is considered CC
  interaction.
• Tagging efficiency 50, including muon capture,
  next slide

Before 37, bug
4
Muon capture
Muon capture also produces delayed hits
4000 decays 4000 captures
Composition of delayed hits
Muon generated at 0.0 ns, plot from 100.0 ns
Neutron spectrum
From nucleus de-excitation, GEANT4 not ideal
Delayed hits from muon capture
MeV
5
Delayed hits from NC single ?0 production
16,000 single NC ?0
not understood
NC single ?0 can be mistaken as muon decay
6
Short track detection

• Detect the longer side using Hough transform
• Make that the longer side is muon-like by
  counting the number of hits in each layers.
• Find the short side by angular scanning at both
  ends of the longer side. The short side appear as
  a peak in the angular histogram.
• Make sure that the open angle gt 15 degrees, and
  no more than 2 hits within the open angle.
• Make sure that there are fewer than 5 remaining
  hits not associated with the V.

First found by the Hough transform
Angular histogram around these points
7
?0 purity update

• MC single NEUT ?/spill, 100,000 spills
• Include the new muon decay tagging
• Include the short track detection

Efficiency 18 Purity 47
21
before 35
32
47
Reconstructed Energy (MeV)
8
Efficiency loss by different cuts
Charged-current ?- rejection efficiency 99.8

• Particle ?0
  ?-
• All 1067
  69420
• Muon-like cut 1029 33038
• Unmatched 993 26291
• Muon decay cut 906 17606
• Low hits cut 775 8393
• Shower cut 496 3787
• Invariant cut 286 1385
• Fiducial cut 198 135
• counts ? ?0 loss by cuts
• 38 3.56
• 36 3.37
• 87 8.15
• 131 12.28
• 279 26.15

CUTS
15
Room for efficiency improvement
9
?0 reconstruction challenge
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?0 reconstruction summary

• Current implementation was originally written by
  K.Kobayashi, partly rewritten by Clark/Trung.
• Work need to be done
• Improve vertex finder
• Energy reconstruction/calibration
• Energy leaking study

Deviation from true vertex
? 3cm
? 4cm
? 0.1
Energy resolution, 350 MeV, fully contained ?0
11
SUMMARY

• Improve muon decay tagging
• Neutrons in NC interactions cause ?0 mistaken as
  muon decay.
• Short track detection
• What needs to be improved ?0 reconstruction