MiniBooNE neutrinos in the MINOS Near Detector

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MiniBooNE neutrinos in the MINOS Near Detector

• D. Bogert, H. J. Kang, S. Murgia,
• P. Shanahan, W. Smart, S. Wojcicki,
• T. Yang

Fermilab and Stanford University
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Outline

• Motivation (in Stans internal note)
• Measure K production cross section
• Determine energy scale of our detectors using
  monochromatic ?? spectrum from K decays
• Understand signal/background separation of ?e
  events from K decays the event rates and energy
  of ?e are lower than ?? but the predicted number
  of ?e events is accurate
• Determine relative cross section for different
  neutrino interaction channels at 1.5 GeV
  separate the resonant channel from DIS.
• Introduction
• Results from data and MC analysis
• Conclusion/Ongoing work

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Geometry of targets and detectors
MINOS ND
? off-axis angle to the MINOS detector 9.13
deg ? incident angle of MiniBooNE neutrinos on
MINOS ND 16.9 deg
MiniBooNE Detector
?
?
MiniBooNE Target
Expected angles in NDzenith angle 83.5
deg azimuth angle 172.8 deg (global coordinate)
Numi Target
Projected view of the geometry
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Kinematics of MiniBooNE ?
M pion or kaon massm muon mass? neutrino
angle in the lab frame 9.13 deg ? neutrino
angle in the CM frame
Energy of ? from K decay is 1.5GeVEnergy of ?
from ? decay is 189MeV cannot separate from the
noise .
Energy of ? from K decay is almost independent of
the parent energy spectrum
?0.159?0.0012 rad S. Murgia
S. Wojcicki
Monochromatic test beam
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MiniBooNE ? Event Selection Cuts-First Try
obtained MiniBooNE (ACNET) spill time stamps
from Feb. to Dec., 05 (Steve Brice)

• Event Selection (Oct. data)
• zenith angle should be 43.5,123.5
• event vertex r lt 1m wrt the NuMI beam center,
  vtx_z0.5,6
• no hits in the top 3 strips
• time difference between MiniBooNE timestamp and
  our cosmic timestamp lt 500?s

?? angle between track direction and expected
MiniBooNE ? direction Standard Cosmic Data with
pre-scale factor 2
maybe NC events
Good numu CC neutrinos
dt -400us
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Correct direction and timing Long muon track
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very close to MB ? direction clean muon track
(one of the best events)
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The track direction is wrong but timing is
consistent with a MB spill. Ongoing work
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Simona implemented a filter package to select
snarls around MiniBooNE spill timestamps
We reprocessed cosmic data with timing within ?1
ms of MiniBooNE spill times double the data set
by removing the pre-scale factor Data processed
are from Aug. to Oct. 2005

• We loosened the event selection cuts
• event vertex containment
• timing consistence with MB spills

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Mostly good CC events
Mostly NC, ?e and noise
Time difference between Minos timestamp and the
nearest MiniBooNE spill timestamp as a function
of cos (??) For events with timing consistent
with MB spills, mis-reconstructed track
directions are corrected in this plot
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Timing resolution
Time difference vs nsecs for events
Residual after linear time correction
? sec
Using only Mostly good CC events cos(??) gt
0.6 Time difference distribution is wide (50us)
vs MiniBooNE spill time 2us. Cause one timing
oscillator counts nanosecs slightly slower or
faster than a nanosecond. New timing requirement
- 15 ?s after the linear time correction
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W.Smart
Energy is ?? CC is peaked at 1.5 GeV and is
almost monochromatic Predicted number of ?? CC
events in Oct. based on this MC from K is about
40.
?
K
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• Peter S. generated 15K ?? CC events and 5K ?e CC
  and ?? NC events, with a 1/E flux between 0.1 and
  4 GeV with the correct directions of MiniBooNE ?
  events
• The MC events are weighted with Wess flux
  distribution
• The MC events are normalized with data POT
  (Peter S.) and are required to pass our cosmic
  triggers (activity or plane trigger)
• Activity Trigger 10 planes with PH
• Plane Trigger 10 consecutive planes with PH
  out of 12 planes

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Trigger efficiencies for different ? interactions
?e CC
?? CC
?? NC
activity
10/12 plane
Simulated E4
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Data and MC comparison using mostly good CC
events
Red circle data Black line MC
Data sample over three months after reprocessing
Angle reconstruction
POT are from ACNET (R. Zwaska)
cos (???
MC and data agree well
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Data and MC comparison using good CC events
continued
Red circle data Black line MC
Track direction reconstruction
MC simulate the wrong directions
Data and MC agree well for azimuth angle
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Track momentum and neutrino energy reconstruction
Red circle data Black line MC
Preliminary
E?
The measured energy is peaked around 1.3 GeV
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• Conclusion and ongoing work
• Observed number of ?? MiniBooNE CC events in ND
  over three months is 56 (Expected numbers of MC
  CC events is 56.5)
• MC and data comparison study shows good
  agreement
• Process more data (Feb. Dec. 2005)
• Need to understand the track direction
  reconstruction to improve the purity and
  efficiency of MB event selection
• Simona is investigating the algorithm of
  determining track directions
• Tingjun and I are looking at pulser shapes of
  stripends
• timing calibration ongoing need help
• The MiniBooNE spill signal is sent to MINOS for
  use as an external trigger

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Attempt to calibrate digit timing
Digit time corrected for the fiber length vs the
distance of a hit from the vertex of a track
Ideally, it should be linear???
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Correct direction and timing