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Status of the PINGU DetectorStefan Söldner-Rembold, University of Manchester
for the IceCube/PINGU Collaboration
TAUP - International Conference on Topics in Astroparticle and Underground Physics, Torino, Italy, 7-11 September 2015
TAUP 2015 - S Söldner-Rembold 2
TAUP 2015 - S Söldner-Rembold
The IceCube Neutrino Telescope
3
Digital Optical Module
TAUP 2015 - S Söldner-Rembold
IceCube/DeepCore
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TAUP 2015 - S Söldner-Rembold
IceCube
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• 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
TAUP 2015 - S Söldner-Rembold
IceCube
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• 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
TAUP 2015 - S Söldner-Rembold
IceCube
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• 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
TAUP 2015 - S Söldner-Rembold
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
• 5m DOM spacing
8
10 TeV 1 EeV1 TeV100 GeV10 GeV1 GeV100 MeV10 MeV
DeepCore IceCube
125m
75m
TAUP 2015 - S Söldner-Rembold 9
• 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
IceCube + DeepCore + PINGU
22m
10 TeV 1 EeV1 TeV100 GeV10 GeV1 GeV100 MeV10 MeV
DeepCorePINGU IceCube
75m
125m
TAUP 2015 - S Söldner-Rembold 10
Neutrino Mass Hierarchy/Ordering
Knowledge of mass hierarchy has implications for
- Neutrino mass determinations - Neutrinoless double-β decay - CP violation searches
TAUP 2015 - S Söldner-Rembold
Mass Hierarchy Determination• Exploit the difference in oscillation probability for ν and anti-ν
• Combine with differences in ν and ν cross-section, flux
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11
22
TAUP 2015 - S Söldner-Rembold
Neutrino Oscillograms
σ(νN) ≈ 2 σ(νN) Φ(νN) ≈ 1.3 Φ(νN) Patterns are therefore different even after addition.
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νμ IH
νμ NHνμ NH
νμ IH
+
+
Probabilities
TAUP 2015 - S Söldner-Rembold 13
• Sum of νμ and νμ
• Expect after cuts:
- 50k/year for νμ +νμ
- 38k/year for νe +νe
• Reconstruction and particle identification not included here
Neutrino Oscillograms
TAUP 2015 - S Söldner-Rembold 14
• Sum of νμ and νμ
• Expect after cuts:
- 50k/year for νμ +νμ
- 38k/year for νe +νe
• Reconstruction and particle identification not included here
Neutrino Oscillograms
TAUP 2015 - S Söldner-Rembold
Resolutions, Particle ID
CC νμ correctly identified with an efficiency of 80% (E >10 GeV)
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Muons:
True neutrino Energy (GeV)0 5 10 15 20 25 30
)° Z
enith
(ν
Res
olut
ion
on
0102030405060708090
(Run 215, v15)µνSample:
0
200
400
600
800
1000
1200
1400
1600
1800
2000
2200
Red line is median
(Run 215, v15)µνSample:
TAUP 2015 - S Söldner-Rembold
Event Signatures
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Time
Early Late
CC Muon Neutrino νμ + N μ + X
“Track”
NC Neutrino νX + X νX + X
“Cascade”
high-energy eventsreconstruct energies and angles, PID
TAUP 2015 - S Söldner-Rembold
Mass Hierarchy Determination
• Difference in counts between hierarchies illustrate discrimination power.
• Background rejection criteria not included, but includes reconstruction/PID.
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Cascade-Like Events Track-Like Events
PRELIMINARY PRELIMINARY
TAUP 2015 - S Söldner-Rembold
Analysis MethodsCurrently studying two methods: Log Likelihood Ratio (more CPU intensive)
• uses Monte Carlo pseudo-data to construct a distribution of the test statistic
Δχ2 pull method (less CPU intensive) • use error propagation for linear
parameters, scan the non-linear ones • analytically minimize the test statistic
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TAUP 2015 - S Söldner-Rembold
• Oscillation Parameters (based on nu-fit values [1])
- dominant uncertainties (no priors): θ23, Δm231
• Detector/Flux/Cross Sections
- normalisation (no prior) - energy scale (10%) - νe/νμ ratio (3%) [2] - ν/anti-ν ratio (10%) [2.3] - atmospheric flux spectral index (3%) [2] - cross section [3] and detailed atmospheric flux uncertainties [2] using fast methods.
[1] M.C Gonzales-Garcia et al., JHEP 1411:052, 2014 [2] G.D. Barr et al., Phys. Rev. D74:094009, 2006 [3] C. Andreopoulos et al., Nucl. Instrum. Meth.A614:87-104, 2010
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Systematic Uncertainties
TAUP 2015 - S Söldner-Rembold
The Bottom Line
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PRELIMINARY
TAUP 2015 - S Söldner-Rembold
Systematic Effects• Investigate the most
significant systematics • Oscillation parameters
have the largest effect, primarily θ23
• DeepCore serves as ‘prototype’ to validate analysis methods (see talk by J.-P. Athayde Marcondes de André)
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PRELIMINARY
Type 3-year σ (NMH)
3-year σ (IMH)
Statistical only 4.84 4.82
Flux only 4.55 4.56
Detector only 4.06 3.99
θ23 only 3.52 3.26
Oscillation only
2.96 2.53
All 2.8 2.54
TAUP 2015 - S Söldner-Rembold 22
Octant Dependance
Strong dependence of sensitivity on octant.
Current sensitivity close to ‘worst case’.
TAUP 2015 - S Söldner-Rembold
43
IceCube 2014 [NH]T2K 2014 [NH] - With SystematicsT2K 2014 [NH] - No SystematicsPINGU [NH] 3year - Best FitPINGU [NH] 3 year - Maximal Mixing3.0
3.5
2.5
0.302.0
0.35 0.40 0.45 0.50 0.55 0.60 0.65 0.70
sin2(θ23)
|∆m
2 31|[10
−3eV
2]
PRELIMINARY
IceCube 2014
Normal mass ordering assumed, 90% CL contours
PINGU 3 year, Fogli 2012 global inputs
PINGU 3 year, NuFit 2014 global inputs
PINGU 3 year, maximal mixing
IceCube 2015 (3-year DeepCore - projected*)
*does not yet include full systematic uncertainties
Other Analyses
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PRELIMINARY
PRELIMINARY
Dark Matter
Mixing
Tau-neutrinoAppearance
+ Earth Tomography
TAUP 2015 - S Söldner-Rembold
Outlook• PINGU is an integral part of the IceCube-Gen2
observatory to enhance the existing IceCube/DeepCore programme
• PINGU will be the first deployed of the new strings • Data taking could start 4-5 years following approval • Revised LoI available soon (currently at arXiv:
1412.5106)
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TAUP 2015 - S Söldner-Rembold
Conclusion
• IceCube and DeepCore have successfully demonstrated that particle physics is possible in ice.
• PINGU will provide insight into the nature of the NMH and measure oscillation parameters.
25
TAUP 2015 - S Söldner-Rembold
BACK UP
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TAUP 2015 - S Söldner-Rembold
Events per Year
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PRELIMINARY PRELIMINARY
TAUP 2015 - S Söldner-Rembold 28
Future of the NMH Measurement• MANY caveats
• median outcome shown
• width indicates effect of main uncertainty (δCP, θ23)
• dates are also bound to change as time goes on
TAUP 2015 - S Söldner-Rembold
The IceCube Neutrino Telescope
29
IceCube
DeepCore
PINGU
Skiway
South Pole Station
TAUP 2015 - S Söldner-Rembold
Atmospheric Neutrinos
• Source of neutrinos is the interaction of particles in the atmosphere
• These interactions produce neutrinos with an understood flux and flavour content
30
TAUP 2015 - S Söldner-Rembold
The IceCube Neutrino Telescope
31
IceCube
DeepCore
Skiway
South Pole Station