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ORCA from ANTARES modules J. Brunner 06/10/2012
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Detector Hexagonal layout a la IceCube 37 lines, distance 20m 25 ANTARES storeys z = 4.5m Equipped volume V = 108x120x120 m 3 M = 1.5 Mton
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MC samples Neutrinos (genneu) NC/CC, e, µ 1 GeV - 1 TeV, Bartol flux muons from Mupage km3 (µ) + geasim ; 100 kHz flat noise – Is diffusion really needed here ? 2T3 trigger Reconstruction & Event selection – BBfit, inter-floor causality 80 30nsec – 1L & ML as for ANTARES oscillation search
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Comparison of effective masses µ CC e CC NC ORCA DeepCore PINGU At least 1 “hot spot” At least 6 storeys with “selected” hits Single & Multi line No quality criteria
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Selection of clean neutrino sample Standard ANTARES BBfit selection does not work – example here : Multi-Line events Ignored in the following, Track fit quality cut is anyway applied µ CC ; µ NC e CC ; e NC
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Example µ Event Displays 1.6 GeV 59.4˚ µ 1.6 GeV 56.9˚ 600 nsec 150 m
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Example µ Event Displays 1.9 GeV 84.3˚ µ 1.8 GeV 77.6˚ 600 nsec 150 m
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Example µ Event Displays 6.8 GeV 35.0˚ µ 5.7 GeV 38.7˚ 600 nsec 150 m
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arXiv:1205.7071, Fig. 1 Coded as suggested in hep-ph/9808270 Earth profile: 2 density approximation Mantle density 5 g/cm3 Core density 12 g/cm3 Oscillation Probabilities with matter effects
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Observable E/cos as for ANTARES analysis Main effect along diagonal lines sub-optimal but easier to get feeling for size of the effect Akhmedov, Razzaque, Smirnov : arXiv:1205.7071 E =0 =0 no syst 45.5 E =2 GeV = 11.25˚ no syst 16.3
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Preliminary sensitivity Assumptions: Selection is perfect – No remaining events from atm. Muons – No remaining events from NC Final event sample built from following components for both hypothesis : NH / IH – P( µ µ ) µ µ + P( µ e ) µ e – P( e µ ) e µ + P( e e ) e e
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Preliminary sensitivity Assumptions: Selection is perfect – No remaining events from atm. Muons – No remaining events from NC Final event sample built from following components for both hypothesis : NH / IH – P( µ µ ) µ µ + P( µ e ) µ e – P( e µ ) e µ + P( e e ) e e e = 0
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Preliminary sensitivity Pseudo-data created by Gaussian smearing from NH MC sample (not shown on plots) Assume 5 full years data taking ² calculated by comparing Pseudo-data versus IH MC – 380 bins in 2-dim histo E (1GeV) versus cos (0.05) – 59 bins in E/cos (1-60 GeV) – 19 bins in E/cos (1-20 GeV) P-value from ² probability
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Final Event sample NH 63915 events IH 64050 events NH 48449 events IH 48564 events Neutrino Energy Cos(Zenith) MC truth Neutrino Difference between NH/IH not exploitable in these two projections
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Step 1 Neutrino energy and zenith are measured Perfect measurement of E and cos ²= 148.3/19 ; p-value 4.7 10 -22 ; = 9.6 5 years of data bins of 1 GeV Normal hierarchy Inverted hierarchy 15315 15518
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Step 2 Neutrino energy and zenith are measured Gaussian smearing of E (2 GeV) and cos (0.05) ²= 40.4/19 ; p-value 2.9 10 -3 ; = 2.8 5 years of data bins of 1 GeV Normal hierarchy Inverted hierarchy
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Step 3 Neutrino energy and zenith are measured Gaussian smearing of E (2 GeV) and (11.25˚) ²= 24.8/19 ; p-value 0.17; = 0.97 5 years of data bins of 1 GeV Normal hierarchy Inverted hierarchy
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Comparison of significance Used SampleARS paperARS methodThis method 1d histo 19 bins 11.4 9.6 1d histo 59 bins 12.1 8.6 2d histo 380 bin 45.5 13.7 8.4 Step 1
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Comparison of significance Used SampleARS paperARS methodThis method 1d histo 19 bins 4.0 2.8 1d histo 59 bins 4.5 2.6 2d histo 380 bin 16.3 (?)6.7 2.3 Step 2
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Comparison of significance Used SampleARS paperARS methodThis method 1d histo 19 bins 2.7 1.0 1d histo 59 bins 2.9 1.4 2d histo 380 bin 16.3 (?)4.1 1.1 Step 3
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Step 4 Neutrino energy and Muon zenith are measured Perfect measurement of E and cos µ ²= 32.6/19 ; p-value 0.0264 ; = 1.94 5 years of data bins of 1 GeV No oscillations Normal hierarchy Inverted hierarchy 30141 15121 15345
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Step 5 Only the muon is measured Perfect measurement of E µ and cos µ ²= 18.0/19 ; p-value 0.52 ; = …… 5 years of data bins of 1 GeV No oscillations Normal hierarchy Inverted hierarchy 41895 19859 20055
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Conclusion Measurement of muon alone (even perfect) is NOT sufficient to reach the goal ! Zenith angle alone is NOT sufficient Moderate Gaussian smearing deteriorates measurement strongly Need new method for background suppression How to calculate significances ?
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Backup
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Next steps Detector setup with Multi-PMTs – 49 lines (7x7 square) ; interstring distance 20m – 6m between storeys ; 20 storeys per string – total 980 storeys and 30380 (small) PMTs – Production currently running Detector embedded in ANTARES – Use ANTARES as veto – Modify tools to work with different OMs Interface to GLOBES for P osc and to neutrino flux library (APC/IPHC) New method for significance calculation (D. Franco, APC)
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Inclusion of misreconstructed e CC Neutrino energy and zenith are measured Perfect measurement of E and cos ²= 92.1/19 ; p-value 1.43 10 -11 ; = 6.65 5 years of data bins of 1 GeV No oscillations Normal hierarchy Inverted hierarchy 38501 24953 24882 Includes 38% misreconstructed e CC
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Step 2 Muon energy and Neutrino zenith are measured Perfect measurement of E µ and cos ²= 19.2/19 ; p-value 0.44 ; = 0.14 5 years of data bins of 1 GeV No oscillations Normal hierarchy Inverted hierarchy 41458 19030 19223 Without e CC
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