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Neutrinos at the South Pole with IceCube,
DeepCore and PINGU
Ken Clark, SNOLAB
SNOLAB Users Meeting - Sept 1, 2016
Neutrinos• Neutrinos obviously
need no introduction at SNOLAB
• VERY light, neutral particles
• Only interact very weakly • Very prevalent in the
universe • Three flavours
2
SNOLAB Users Meeting - Sept 1, 2016
Sources of Neutrinos• Experiments study neutrinos from different
sources
• Solar neutrinos (Homestake, Borexino, SNO)
• Reactor neutrinos (KamLAND, Daya Bay, RENO)
• Neutrino Beams (MINOS, T2K, OPERA)
• Atmospheric Neutrinos (SuperK, Antares, IceCube)
3
SNOLAB Users Meeting - Sept 1, 2016
Atmospheric Neutrinos
• Source of neutrinos is the interaction of particles in the atmosphere
• These interactions produce neutrinos with an understood flux and flavour content
4
SNOLAB Users Meeting - Sept 1, 2016
Neutrino Energy Spectrum
5
• Studying neutrinos at high energies was the motivation
• Success with intermediate IceCube configurations
GeV TeV PeV EeV
SNOLAB Users Meeting - Sept 1, 2016 6
100
10Events
/km2 year
GeV TeV PeV EeV
• Studying neutrinos at high energies was the motivation
• Success with intermediate IceCube configurations
Neutrino Energy Spectrum
SNOLAB Users Meeting - Sept 1, 2016
Detector Wish List
• In order to detect these neutrinos, a detector was needed which would:
1. Have a large target mass 2. Provide a very clear medium so that
light can be detected 3. Be at least somewhat shielded from
outside radiation
7
SNOLAB Users Meeting - Sept 1, 2016
IceCube/DeepCore
8
Skiway
South Pole Station
SNOLAB Users Meeting - Sept 1, 2016
The IceCube Neutrino Telescope
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SNOLAB Users Meeting - Sept 1, 2016 10
The IceCube Neutrino Telescope
SNOLAB Users Meeting - Sept 1, 2016
Detection Method
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muon
neutrino
interaction
SNOLAB Users Meeting - Sept 1, 2016
IceCube Events
• Usual map overlay of event?
12
SNOLAB Users Meeting - Sept 1, 2016
Events in the Detector
• Events are separable using their signature in the detector
13
Time
Early Late
CC Muon Neutrino νμ + N μ + X
“Track”
NC Neutrino νX + X νX + X
“Cascade”
SNOLAB Users Meeting - Sept 1, 2016
Event Selection
• Use an extensive veto to remove specific classes of events
• Want to retain only events which have their first interaction inside the detector
14
IceTop Water Tanks
1.45 km
90 m
2450m
2085m2165m
Veto Region
Dust Layer
Veto Region
SNOLAB Users Meeting - Sept 1, 2016
Event Selection
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YES NO
SNOLAB Users Meeting - Sept 1, 2016
Why So Strict?
• This is 10 ms of data
• In one year IceCube will detect:
~1011 atmospheric muons (3000 per second)
~105 atmospheric ν->μ (1 every 6 minutes)
~10 cosmic ν->μ
16
SNOLAB Users Meeting - Sept 1, 2016
Analysis Preparation
• Several aspects required to prepare for the full analysis of the high energy events
• Need to determine the number of neutrinos expected and their energy spectrum
• Need to verify the veto procedure with existing data/Monte Carlo
17
Anticipated Events
Atmospheric μ: Determined from experimental data using
the new veto 6±3.4
Atmospheric ν: Determined using Monte Carlo simulation
and previous data 4.6+3.7-1.2
SNOLAB Users Meeting - Sept 1, 2016
IceCube Results
1.04±0.16 PeV
• Try out these new methods on a subsample of the IceCube data
• Completely unexpectedly, two very high energy events were found (and named)
18
1.14±0.17 PeV
SNOLAB Users Meeting - Sept 1, 2016
IceCube Results
1.04±0.16 PeV
19
1.14±0.17 PeV
• Try out these new methods on a subsample of the IceCube data
• Completely unexpectedly, two very high energy events were found (and named)
SNOLAB Users Meeting - Sept 1, 2016
IceCube Results
1.04±0.16 PeV
20
1.14±0.17 PeV
• Try out these new methods on a subsample of the IceCube data
• Completely unexpectedly, two very high energy events were found (and named)
SNOLAB Users Meeting - Sept 1, 2016
Predicted Results
21
Expected to see 10.6+5.0-3.6
SNOLAB Users Meeting - Sept 1, 2016
Actual Results
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Actually saw 28 (in the first 2 years of data)
SNOLAB Users Meeting - Sept 1, 2016
IceCube Results
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(This has been updated to ~3 years)
SNOLAB Users Meeting - Sept 1, 2016
Source?
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There is no convincing source so far…
SNOLAB Users Meeting - Sept 1, 2016
Highest Energy
• Ernie & Bert stood as the highest energy events for some time
• During the full analysis, a new record-setting event was found
25
2.2 PeV
SNOLAB Users Meeting - Sept 1, 2016
On to the Next Analysis
• Want to expand beyond just high energy neutrino detection
• Neutrino oscillations are very exciting field right now…
• Why not see if we can do something with those?
26
SNOLAB Users Meeting - Sept 1, 2016
Neutrino Oscillations
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• SNOLAB users probably don’t need an introduction to oscillations
• The oscillation pattern is shown here
Blue: muon neutrino Red: tau neutrino
Black: electron neutrino
Image credit: Wikipedia
SNOLAB Users Meeting - Sept 1, 2016
Atmospheric Neutrinos
• Source of neutrinos is the interaction of particles in the atmosphere
• These interactions produce neutrinos with an understood flux and flavour content
28
SNOLAB Users Meeting - Sept 1, 2016
Neutrino Oscillations
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Blue: muon neutrino Red: tau neutrino
Black: electron neutrino
Image credit: Wikipedia
• IceCube has a maximum path length of ~13000 km • If the lower energy threshold is ~200 GeV, L/E <~65
SNOLAB Users Meeting - Sept 1, 2016
Neutrino Oscillations
30
• IceCube has a maximum path length of ~13000 km • If we can lower the energy threshold to ~10 GeV, L/
E <~1300
Blue: muon neutrino Red: tau neutrino
Black: electron neutrino
Image credit: Wikipedia
SNOLAB Users Meeting - Sept 1, 2016
IceCube
31
• 78 Strings
• 125m string spacing
• 17m DOM spacing
• Add 8 strings
• 75m string spacing
• 7m DOM spacing
• Add 20 strings
• 26m string spacing
• 5m DOM spacing10 TeV 1 EeV1 TeV100 GeV10 GeV1 GeV100 MeV10 MeV
IceCube
SNOLAB Users Meeting - Sept 1, 2016
IceCube
32
• 78 Strings
• 125m string spacing
• 17m DOM spacing
• Add 8 strings
• 75m string spacing
• 7m DOM spacing
• Add 20 strings
• 26m string spacing
• 5m DOM spacing10 TeV 1 EeV1 TeV100 GeV10 GeV1 GeV100 MeV10 MeV
IceCube
125m
SNOLAB Users Meeting - Sept 1, 2016
IceCube + DeepCore
• 78 Strings
• 125m string spacing
• 17m DOM spacing
• Add 8 strings
• 75m string spacing
• 7m DOM spacing
• Add 20 strings
• 26m string spacing
33
75m
10 TeV 1 EeV1 TeV100 GeV10 GeV1 GeV100 MeV10 MeV
DeepCore IceCube
125m
SNOLAB Users Meeting - Sept 1, 2016
The IceCube Neutrino Telescope
34
IceCube
DeepCore
Skiway
South Pole Station
SNOLAB Users Meeting - Sept 1, 2016
DeepCore Results
35
Phys. Rev. D 91 072004 (2015)
• Approximately 3 years of data analyzed
• High rate in detector provides large event sample
• Oscillation parameter constraints approaching those of dedicated experiments
SNOLAB Users Meeting - Sept 1, 2016
DeepCore Results
36
• Approximately 3 years of data analyzed
• High rate in detector provides large event sample
• Oscillation parameter constraints approaching those of dedicated experiments
Phys. Rev. D 91 072004 (2015)
SNOLAB Users Meeting - Sept 1, 2016
Even Lower Energies
• Deep Core is a success, but we get access to more physics with a lower threshold
37
• muon neutrino disappearance
• maximal θ23 measurement
• lower energy dark matter
• neutrino mass hierarchy
SNOLAB Users Meeting - Sept 1, 2016
IceCube + DeepCore• 78 Strings
• 125m string spacing
• 17m DOM spacing
• Add 8 strings
• 75m string spacing
• 7m DOM spacing
• Add 20 strings
• 26m string spacing
38
75m
10 TeV 1 EeV1 TeV100 GeV10 GeV1 GeV100 MeV10 MeV
DeepCore IceCube
125m
SNOLAB Users Meeting - Sept 1, 2016
• 78 Strings
• 125m string spacing
• 17m DOM spacing
• Add 8 strings
• 75m string spacing
• 7m DOM spacing
• Add 40 strings
• 22m string spacing
• 3m DOM spacing
39
IceCube + DeepCore + PINGU
125m22m
75m
10 TeV 1 EeV1 TeV100 GeV10 GeV1 GeV100 MeV10 MeV
DeepCorePINGU IceCube
SNOLAB Users Meeting - Sept 1, 2016
Improvement with PINGU
40
DeepCore PINGU
Neutrino energy: 12 GeV Lepton energy: 10 GeV
SNOLAB Users Meeting - Sept 1, 2016
The IceCube Neutrino Telescope
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IceCube
DeepCore
PINGU
High EnergyExtension
Skiway
South Pole Station
SNOLAB Users Meeting - Sept 1, 2016
Mass Hierarchy Determination
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1
1
SNOLAB Users Meeting - Sept 1, 2016 43
1
1
2
2
Mass Hierarchy Determination
SNOLAB Users Meeting - Sept 1, 2016
Neutrino Oscillograms
• The cross-section and flux are different for νμ and νμ
• The patterns are therefore different!
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SNOLAB Users Meeting - Sept 1, 2016
Neutrino Oscillograms
• Sum of νμ and νμ
• Reconstruction and PID not included here
45
SNOLAB Users Meeting - Sept 1, 2016
Neutrino Oscillograms
46
• Sum of νμ and νμ
• Reconstruction and PID not included here
SNOLAB Users Meeting - Sept 1, 2016
So Why am I Talking Here?
• PINGU is investigating using new DOMs with multiple PMTs
• Need to study how these would work in a low background environment
47
SNOLAB Users Meeting - Sept 1, 2016
So Why am I Talking Here?
• PINGU is investigating using new DOMs with multiple PMTs
• Need to study how these would work in a low background environment
48
SNOLAB Users Meeting - Sept 1, 2016
Conclusion
• IceCube and DeepCore have been very successful and have shown that particle physics is possible in ice
• PINGU will provide insight into the nature of the NMH as well as the oscillation parameters
• SNOLAB is an ideal site to test the new PMT structures
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SNOLAB Users Meeting - Sept 1, 2016
Exciting Times To Come!
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SNOLAB Users Meeting - Sept 1, 2016 51
SNOLAB