ORCA simulations - First steps J. Brunner 06/09/2012.
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Transcript of ORCA simulations - First steps J. Brunner 06/09/2012.
ORCA simulations - First steps
J. Brunner06/09/2012
Detector
• Hexagonal layout a la IceCube• 37 lines, distance 20m• 25 ANTARES storeys • z = 4.5m
• Equipped volume• V = 108x120x120 m3
• M = 1.5 Mton
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 8030nsec– 1L & ML as for ANTARES oscillation search
Selection of clean neutrino sample
• Standard ANTARES BBfit selection does not work (example MultiLine events)
µ CC ; µ NC e CC ; e NC
arXiv:1205.7071, Fig. 1Coded as suggested inhep-ph/9808270
Earth profile: 2 density approximationMantle density 5 g/cm3Core density 12 g/cm3
Oscillation Probabilities with matter effects
Oscillation Probabilities with matter effects
arXiv:1205.7071, Fig. 1
Earth profile:Full PREM model
From interface to GLOBESWork at APC/IPHC ongoing
Courtesy : A. Meregalia IPHC
Oscillation Probabilities with matter effects
arXiv:1205.7071, Fig. 2
Earth profile:Full PREM model
From interface to GLOBESWork at APC/IPHC ongoing
Courtesy : A. Meregalia IPHC
Observable E/cos as for ANTARES analysis
• Main effect along diagonal lines – sub-optimal
Akhmedov, Razzaque, Smirnov : arXiv:1205.7071
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(µ µ ) µ µ + P(µ e ) µe
– P(e µ ) e µ + P(e e ) e e
– P(e µ ) e µ + P(e e ) e e
Preliminary sensitivity
• Pseudo-data created by Gaussian smearing from NH MC sample (not shown on plots)
• ² calculated from 19 bins (1-20 GeV) by comparing Pseudo-data versus IH MC
• P-value from ² probability
Step 1• Only the muon is measured• Perfect measurement of Eµ and cosµ
• ²= 18.0/19 ; p-value 0.52 ; = ……
5 years of databins of 1 GeV
No oscillationsNormal hierarchyInverted hierarchy
418951985920055
Without e CC
Step 2• Muon energy and Neutrino zenith are measured• Perfect measurement of Eµ and cos
• ²= 19.2/19 ; p-value 0.44 ; = 0.14
5 years of databins of 1 GeV
No oscillationsNormal hierarchyInverted hierarchy
414581903019223
Without e CC
Step 3• Neutrino energy and Muon zenith are measured• Perfect measurement of E and cosµ
• ²= 32.6/19 ; p-value 0.0264 ; = 1.94
5 years of databins of 1 GeV
No oscillationsNormal hierarchyInverted hierarchy
301411512115345
Without e CC
Step 4• Neutrino energy and zenith are measured• Perfect measurement of E and cos
• ²= 136.6/19 ; p-value 8.2 10-20 ; = 9.03
5 years of databins of 1 GeV
No oscillationsNormal hierarchyInverted hierarchy
297661531515518
Without e CC
Step 5• 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 databins of 1 GeV
No oscillationsNormal hierarchyInverted hierarchy
385012495324882
Includes 38% misreconstructed e CC
Conclusion
• Measurement of muon alone (even perfect) is NOT sufficient to reach the goal !
• Need new method for background suppression• Some contamination from e can be accepted• Must go beyond BBfit & Co….
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 Posc and to neutrino flux library (APC/IPHC)
• New method for significance calculation (D. Franco, APC)