ORCA from ANTARES modules J. Brunner 06/10/2012

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

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

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

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

Example µ Event Displays 1.6 GeV 59.4˚ µ 1.6 GeV 56.9˚ 600 nsec 150 m

Example µ Event Displays 1.9 GeV 84.3˚ µ 1.8 GeV 77.6˚ 600 nsec 150 m

Example µ Event Displays 6.8 GeV 35.0˚ µ 5.7 GeV 38.7˚ 600 nsec 150 m

arXiv: , Fig. 1 Coded as suggested in hep-ph/ Earth profile: 2 density approximation Mantle density 5 g/cm3 Core density 12 g/cm3 Oscillation Probabilities with matter effects

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:  E =0   =0 no syst 45.5   E =2 GeV   = 11.25˚ no syst 16.3 

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

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

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

Final Event sample NH events IH events NH events IH events Neutrino Energy Cos(Zenith) MC truth Neutrino Difference between NH/IH not exploitable in these two projections

Step 1 Neutrino energy and zenith are measured Perfect measurement of E and cos   ²= 148.3/19 ; p-value ;  = years of data bins of 1 GeV Normal hierarchy Inverted hierarchy

Step 2 Neutrino energy and zenith are measured Gaussian smearing of E (2 GeV) and cos  (0.05)  ²= 40.4/19 ; p-value ;  = years of data bins of 1 GeV Normal hierarchy Inverted hierarchy

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;  = years of data bins of 1 GeV Normal hierarchy Inverted hierarchy

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

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

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

Step 4 Neutrino energy and Muon zenith are measured Perfect measurement of E and cos  µ  ²= 32.6/19 ; p-value ;  = years of data bins of 1 GeV No oscillations Normal hierarchy Inverted hierarchy

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

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 ?

Backup

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 (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)

Inclusion of misreconstructed e CC Neutrino energy and zenith are measured Perfect measurement of E and cos   ²= 92.1/19 ; p-value ;  = years of data bins of 1 GeV No oscillations Normal hierarchy Inverted hierarchy Includes 38% misreconstructed e CC

Step 2 Muon energy and Neutrino zenith are measured Perfect measurement of E µ and cos   ²= 19.2/19 ; p-value 0.44 ;  = years of data bins of 1 GeV No oscillations Normal hierarchy Inverted hierarchy Without e CC