Partially Contained Atmospheric Neutrino Analysis

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Partially Contained Atmospheric Neutrino Analysis
Andy Blake Cambridge University March 2004
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Introduction

• Far Det data R 18140 22330 (1.2 kT-yrs)
• MC atmos nu R 124 (250 kT-yrs)
• R 1.5 software

MC
data
PhotonTransport / DetSim
FC/PC Filter
AltDemux AtNuReco
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PC digits

• Define fiducial volume
• gt 50cm from detector edge in UV
• gt 4 planes from detector edge in Z

• Combine digits in adjacent views.
• Select events with
• gt 10 PE inside fiducial volume
• gt 5 PE outside fiducial volume beside ONE
  detector edge.

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PC tracks

• Select events with
• ONE track ONE vertex inside fiducial volume.

top vertex contained
bottom vertex contained
upward-going candidate
downward-going candidate
direction problem
containment problem
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Track Quality Cuts (1)
Track Quality Cuts

• Tracks reconstructed by AtNuReco in 1st pass
• gt 7 planes
• gt 30 of total pulseheight
• Simple timing cut
• ( bottom vertex contained ? ?2uplt
  ?2down
• top vertex contained ? ?2downlt ?2up
  )
• Match PC track PC digit containment

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Track Quality Cuts (2)
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Down-Going PC Events
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Down-Going Muons (1)
(1) Pulse Height

• Increase PH cut to 50
• PHtrack / PHtotal gt 0.5
• or
• 400.0 Rsteel / PHtotal gt 0.5

PHtrack / PHtotal gt 0.5
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Down-Going Muons (2)
(2) Trace
TRACE Z
extrapolate track to detector edge calculate Z
distance
Trace Z gt 7 planes
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Down-Going Muons (3)
(3) Track Vertex
Highest pulse-height plane in 3 plane window
around vertex
Furthest off-track hit in 3 plane window around
vertex
Rmax lt 36 strips
Qmax lt 250 PE
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Down-Going Muons (4)
DATA (33 events)
DETECTOR EFFECTS (15 events)
CONTAINED EVENTS (18 events)
CRATE BOUNDARIES (11 events)
HV TRIPS (4 events)
STEEP MUONS (10 events)
IRREDUCIBLE (8 events)
apply veto shield
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Detector Effects Crate Boundaries (1)
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Detector Effects Crate Boundaries (2)
run 20339, snarl 60473
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Detector Effects HV Trips (1)
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Detector Effects HV Trips (2)
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Steep Muons
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Veto Shield

• Use CandShieldPlanks
• Q gt 1 PE
• ?T lt 400 ns
• Yshield gt Ytrack
• Zshield Ztrack
• Estimate tagging efficiency by reducing
  containment cuts
• Tagging efficiency 97
• Estimate accidental tagging by using pre-trigger
  shield hits
• Accidental Tagging 3

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Down-Going Muons (5)
BACKGROUND expected background before
shield 18 4 14 3.5 x signal expected
background after shield 0.03 x 14 0.4 0.1 x
signal
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Down-Going Candidates (1)
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Down-Going Candidates (2)
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Down-Going Candidates (3)
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Down-Going Candidates (4)
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Down-Going Candidates (5)
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Up-Going PC Events
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Up-Going Muons (1)
Timing Cuts

• Fit S-CT with time slope 1
• Calculate RMS for each fit
• Consider RMSup - RMSdown

CT
U view
V view
1/ß -1
1/ß 1
RMSdown RMSup gt 0.3
S
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Up-Going Muons (2)
RMSup lt 1.5 m
RMSdown gt 1.0 m
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Up-Going Muons (3)

• RMS from fitting wrong time slope

0
fit
track
S
RMSup / RANGE lt 0.5
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Up-Going Muons (4)
1/ß gt 0.5
1/ß lt 2.5
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Up-Going Muons (5)
BACKGROUND use MC stopping muons with
tuned timing resolution.
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Up-Going Candidates (1)
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Up-Going Candidates (2)
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Up-Going Candidates (3)
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Up-Going Candidates (4)
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Signal Efficiencies (1)
Containment cuts
Direction cuts
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Signal Efficiencies (2)
Efficiency vs Neutrino Energy
Efficiency vs Muon Zenith Angle
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Conclusion

• Able to extract PC candidates from data.
• Analysed lt50 of data more events to come!
• Further development of analysis.
• Tag events contained due to detector effects.
• Continue battling with steep muons.
• Neutrino energy reconstruction.
• Lots of ideas being developed at Cambridge!