Search for Diffuse Flux 2000-2003

1
Search for Diffuse Flux2000-2003

• Jessica Hodges
• University of Wisconsin - Madison

2
Reminder of Diffuse 2000 Results...

• The 2000-2003 Diffuse Analysis is being done with
  the same methods as used in the 2000 Diffuse
  Analysis done in Madison.

Jessica Hodges Uppsala October 2004
3
Reminder of Diffuse 2000 Results...

• 50 data in unblind sample, 50 data in blind
  sample
• cuts developed on unblind data set
• 5 one-dimensional cuts on
• likelihood ratio (up to down), track length,
  number of direct hits, smoothness, reduced
  likelihood (up)
• used model rejection potential to set final nch
  cut (nchgt80)

Jessica Hodges Uppsala October 2004
4
Reminder of Diffuse 2000 Results...

• 7 data events in unblind sample, 3 events in
  blind sample
• with normalization, expected number of events for
  1 year
• atmospheric ?'s 9.4 events
• E-2 ?'s 25.0 events
• The Feldman-Cousins signal event upper limit for
  10 observed events on a background of 9.4 events
  is
• ?90 7.5
• Thus, the E-2 neutrino flux limit is
• ?90 ? ?90 / nsignal 10-6 7.5 / 25
• limit 3 10-7 GeV / cm2 s sr

Jessica Hodges Uppsala October 2004
5
Diffuse 2000-2003 Status

• The last few months have been spent learning to
  use new tools for the 4-year analysis. The
  datahandler provided by Zeuthen and Sieglinde are
  now being used to process all files so that they
  exactly match the Zeuthen 4-year processing
  chain.
• Monte Carlo files are in preparation.
• Will look at 100 of the data set AFTER all of
  the cuts have been developed on the Monte Carlo
  and I am approved for unblinding.

Jessica Hodges Uppsala October 2004
6
Types of Monte Carlo Used

• Cosmic ray muon background
• muons from air showers created when cosmic rays
  hit the atmosphere
• Coincident muons (a subset of cosmic ray muons)
• two muons or muon bundles from different showers
  going through the detector at the same time
• Atmospheric neutrinos
• neutrinos produced by the decay of pions and
  kaons in the cosmic ray shower
• E-2 neutrinos
• extragalactic sources with E-2 energy spectrum

Jessica Hodges Uppsala October 2004
7
Diffuse 2000-2003 Status

• Nusim files are prepared and the files are
  normalized for atmospheric neutrinos and E-2
  neutrinos.

Jessica Hodges Uppsala October 2004
8
Diffuse 2000-2003 Status

• Downgoing muons files are currently being
  prepared.
• In the 2000 analysis, cosmic ray muon events were
  all cut away by the one-dimensional quality cuts.
  The cuts were tightened until all of the
  downgoing background was eliminated.
• A similar procedure will be followed for the
  4-year analysis.

Jessica Hodges Uppsala October 2004
9
Diffuse 2000-2003 Status

• Since coincident muons were such a challenge in
  the 2000 diffuse analysis, it is important to
  build up large statistics for the four year
  analysis.
• Coincident muon production is in full-swing in
  Madison. The files are being filtered with the
  datahandler.

Jessica Hodges Uppsala October 2004
10
Summary of Processing
Identical to Zeuthen 2000-2003 processing

• Level 1 Hit and OM Cleaning
• Low ToT / amplitude filter
• Direct Walk Reconstruction Zenith(direct
  walk)gt70
• Direct WIMP Reconstruction
• CFirst Reconstruction
• Pandel Reconstruction
• Cascade SPE Reconstruction
• Cascade MPE Reconstruction
• JAMS Reconstruction
• Level 2 Zenith(JAMS)gt80
• Crosstalk cleaning
• Pandel Likelihood Fit (32-fold, JAMS seed)
• MPE Likelihood Fit (16-fold, Pandel seed)
• Bayesian Likelihood Fit (16-fold, Pandel seed)
• Level 3
• Zenith(Pandel)gt80
• Smoothness calculation (Phit Smoothness for
  hits with rlt50m, -25ns lt tres lt 75ns)
• Paraboloid Fit (Siegmund) on Pandel track
• Cascade Likelihood Fit (Siegmund) (16-fold)

For more details, see the Zeuthen 2000-2003 point
source webpages or Markus Ackermann's
presentation from Bommerholz.
Jessica Hodges Uppsala October 2004
11
Diffuse 2000-2003 Status
Obviously, I need some downgoing muons (and
better coincident muon statistics)....
4-year Monte Carlo sample
Level 3 the nch plot before any of the quality
cuts have been applied
Jessica Hodges Uppsala October 2004
12
Diffuse 2000-2003 Status
Obviously, I need some downgoing muons (and
better coincident muon statistics)....
4-year Monte Carlo sample
Level 3 the zenith distribution before any of
the quality cuts have been applied
Jessica Hodges Uppsala October 2004
13
Preliminary look at cuts
Obviously, I need some downgoing muons (and
better coincident muon statistics)....
4-year Monte Carlo sample
Level 3
n-1 plot
keep
cut
n-1 plot cuts made on ldirb(up)gt155 ndirc(up)gt10
smootallphit(up)lt0.275 jkrchi(up)lt7.2
Likelihood ratio (up to down)
The green line drawn on the plot at right
corresponds to the cut level for the 2000
analysis. The cut for the 4-year analysis is not
yet optimized.
Jessica Hodges Uppsala October 2004
14
Preliminary look at cuts
Obviously, I need some downgoing muons (and
better coincident muon statistics)....
4-year Monte Carlo sample
n-1 plot
Level 3
cut
keep
n-1 plot cuts made on jkchi(down)-jkchi(up)gt35 nd
irc(up)gt10 smootallphit(up)lt0.275 jkrchi(up)lt7.2
Track length (up)
The green line drawn on the plot at right
corresponds to the cut level for the 2000
analysis. The cut for the 4-year analysis is not
yet optimized.
Jessica Hodges Uppsala October 2004
15
Preliminary look at cuts
Obviously, I need some downgoing muons (and
better coincident muon statistics)....
4-year Monte Carlo sample
Level 3
n-1 plot
keep
cut
n-1 plot cuts made on jkchi(down)-jkchi(up)gt35 ld
irb(up)gt155 smootallphit(up)lt0.275 jkrchi(up)lt7.
2
Number of direct hits (up)
The green line drawn on the plot at right
corresponds to the cut level for the 2000
analysis. The cut for the 4-year analysis is not
yet optimized.
Jessica Hodges Uppsala October 2004
16
Preliminary look at cuts
Obviously, I need some downgoing muons (and
better coincident muon statistics)....
4-year Monte Carlo sample
Level 3
n-1 plot
cut
keep
cut
n-1 plot cuts made on jkchi(down)-jkchi(up)gt35 ld
irb(up)gt155 ndirc(up)gt10 jkrchi(up)lt7.2
Smoothness (up)
The green line drawn on the plot at right
corresponds to the cut level for the 2000
analysis. The cut for the 4-year analysis is not
yet optimized.
Jessica Hodges Uppsala October 2004
17
Preliminary look at cuts
Obviously, I need some downgoing muons (and
better coincident muon statistics)....
4-year Monte Carlo sample
n-1 plot
Level 3
keep
cut
n-1 plot cuts made on jkchi(down)-jkchi(up)gt35 ld
irb(up)gt155 ndirc(up)gt10 smootallphit(up)lt0.275
Reduced Likelihood (up)
The green line drawn on the plot at right
corresponds to the cut level for the 2000
analysis. The cut for the 4-year analysis is not
yet optimized.
Jessica Hodges Uppsala October 2004
18
Preliminary look at cuts
Obviously, I need some downgoing muons (and
better coincident muon statistics)....
4-year Monte Carlo sample
cuts made on jkchi(down)-jkchi(up)
gt35 ldirb(up)gt155 ndirc(up)gt10 smootallphit(up)lt
0.275 jkrchi(up)lt7.2
Nch plot with preliminary quality cuts applied
The cuts applied correspond to the cut levels
for the 2000 analysis. The cuts for the 4-year
analysis are not yet optimized.
Jessica Hodges Uppsala October 2004
19
Optimizing the nch cut with the Model Rejection
Potential
IF THE CUTS stay exactly the same as they were
for the single year (2000) analysis, then 1)
the best nch cut will be at 124 (it was 80
for the single year analysis) 2) Model Rejection
Factor 0.0848 expected upper limit 0.0848
10-6
8.5 10-8
for four years
Jessica Hodges Uppsala October 2004
20
Optimizing the nch cut with the Model Rejection
Potential
Cuts will be determined after coincident muons
are ready. It is expected that any coincident
muons that survive the quality cuts will be
removed by the much tighter final energy (nch)
cut. Note the nch cut is expected to move from
nch 80 for the single year analysis to nch
124 for the 4-year analysis. More details and an
unblinding proposal in the near future......
Jessica Hodges Uppsala October 2004