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


arXiv:1205.7071, Fig. 1

Earth profile:Full PREM model

From interface to GLOBESWork at APC/IPHC ongoing

Courtesy : A. Meregalia IPHC


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



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



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



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



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)

ORCA simulations - First steps J. Brunner 06/09/2012.

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