CC analysis progress

1
CC analysis progress
D.A. Petyt June 2004

• This talk
• A first attempt at calculating CC energy
  sensitivity using the Far Mock data MC files with
  full reconstruction.
• Quite a few changes from Five year plan plots
• Real events used rather than fast MC with
  histogrammed flux and y distributiuons
• Reconstructed track and shower energies used
  rather than Gaussian-distribution resolution
  functions
• Nuclear effects accounted for including
  intranuclear re-scattering
• Neugen 3 used with flatter y-distribution
• This analysis is not optimised yet should be
  able to improve energy resolution and event
  selection efficiencies

2
Event ID PDFs (top row CC, bottom row NC)
Require that all events contain at least 1
reconstructed track
Event length (planes) Track p.h./event
p.h track p.h./plane (siglin ADC)
3
Event ID PID parameter
CC
NC
4
Selection efficiencies
Cut here
Event reconstruction efficiencies are included in
these numbers
5
CC efficiencies Reco and PID chain
Should be better in R1.8
First 5 efficiency plots are sequential, last
plot is cumulative
6
Energy reconstruction
True NC events

• ErecoEmEhad
• Use track fitter to provide muon momentum range
  for contained tracks, 1/(q/p) for exiting tracks
  (min 3m track length)
• How to estimate Ehad?
• Test some ideas on NC events
• Ehad Shower phscale factor?
• Ehad Event ph scale factor
• Using event ph works better ph/GeV distribution
  has 15 higher mean and narrower width

Number of reco tracks and showers
Fraction of event p.h. in reco shower(s)
Shower p.h./Ehad (siglin ADC units)
Event p.h./Ehad (siglin ADC units)
7
Showers in CC events
True CC events

• Attempt to use same algorithm to estimate shower
  energies in CC events
• Must account for pulse height contribution of
  muon track in shower region.
• Cant use SR trk.ph.siglin, as this includes
  shower ph for strips in which tracks and showers
  overlap
• Estimate track pulse height as trk.ndigit295,
  where scaling factor is determined from long
  muons
• Subtract estimated track p.h. from event ph to
  yield shower energy
• Scaling factor obtained 10500 siglin ADC/GeV

Numerator shw p.h. Denominator event ph
estimated track ph.
Shower p.h./Ehad (siglin ADC units)
Estimated shower p.h./Ehad (siglin ADC units)
8
Resolution functions
All (reco-true)/true
Asymmetric tails caused by shower fluctuations
Small negative bias. Tails mostly due to q/p
errors
9
Pm reconstructed high - Exiting muon with little
or no curvature
10
Pm reconstructed high - Exiting muon with kink
11
Ehad reconstructed high high ph digits
12
Ehad reconstructed high lego plot of snarl 81
13
Comparison of true and reconstructed En spectra
Identified CC-like events PID gt-0.3
True CC events
True NC events
True
Reconstructed
14
Energy spectra and spectrum ratios
Identified CC-like events Dm20.002, sin22q1,
scaled to 16e20 p.o.t
Unoscillated
Oscillated
NC
No NC subtraction in ratio plot
15
Energy spectra and spectrum ratios
Identified CC-like events Dm20.002, sin22q1,
scaled to 16e20 p.o.t
Unoscillated
Oscillated
NC
NC contribution subtracted with 20 error
16
Allowed regions
Dm20.002 eV2, sin22q1, 16e20 p.o.t
Rise in spectrum ratio not seen here
17
Allowed regions - 2
Dm20.00295 eV2, sin22q1, 16e20 p.o.t
Rise in spectrum ratio is observed here
18
Comparison of old and new
5 year plan analysis
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Comparison of old and new
This analysis
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What happened to the low energy rise?

• I can think of 4 likely reasons
• Energy smearing due to nuclear/mass/pion
  absorption effects in NEUGEN. Already saw some
  evidence of this when I compared toy MC event
  generator with NEUGEN last June

21
What happened to the low energy rise?

• Additional smearing caused by non-Gaussian tails
  in resolution functions. Andy Cullings Ehad
  method should help here
• Toy MC used a binned FarDet energy spectrum with
  linear interpolation between bins. Will tend to
  over-estimate event rate in lowest energy (0-1
  GeV) bin
• Track finding efficiency is lower, especially at
  low En

22
Track finding efficiency, old and new
Old (NEUGEN2) MC file, tracker run with cosmic mu
parameters?
Mock Data MC files, tracker run with R1.7

• Track finding efficiency is much higher in the
  old ntuple. I suspect that this is because the
  reconstruction was configured with cosmic
  parameters which contain much looser cuts on what
  constitutues a track plane. Tracks are also
  found in most NC events, but these can be
  suppressed with the PID cut.
• NEW efficiency is set to improve with R1.8 (low
  pm tuning by Niki, bug fixes by Jim)

23
QEL pm distribution
How many of these can we recover?
All events Reco track
PID cut
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What next?

• Re-do analysis with R1.8, which will contain a
  number of reco improvements. How much does this
  help?
• Look into incorporating Andy Cullings Ehad
  prescription to improve shower energy resolution
• Look at events that do not have a reconstructed
  track. Are there usable CC events in this sample?
  How can we extract them?