Low energy option for KM3NeT Phase 1? KM3NeT-ORCA (Oscillation Research with Cosmics in the Abyss) P. Coyle, Erlangen 23 June 2012

Theta_13 is Large

Next Step: Mass Hierarchy normalinverted

5 MSW Effect (two flavors) Oscillation probabilities in vacuum: matter: Matter resonance: In this case: - Effective mixing maximal - Effective osc. frequency minimal For  appearance,  m 31 2 : -  ~ 4.7 g/cm 3 (Earth’s mantle): E res ~ 7 GeV -  ~ 10.8 g/cm 3 (Earth’s outer core): E res ~ 3 GeV Resonance energy:  MH

6 Matter profile of the Earth … as seen by a neutrino (PREM: Preliminary Reference Earth Model) Core Inner core

U. Katz: PINGU 7 MSW effect in Earth induces difference in oscillations Note: first maximum for is at 12 GeV for Could be measurable since at these energies Advanced analysis: “oscillograms” (Alexei Smirnov) Mass hierarchy (atmospheric )

Oscillations with Atmospheric Neutrinos L=2 R Earth cos , from track fit E from muon range Oscillations maximal at 24 GeV for vertical neutrinos (muon range~120m) Larger effect on single-line (low energy) than multi-line (higher energy) events E <100 GeV MC truth 8

Neutrino Oscillations: Track Selection Multi-line Single-line Special low energy fit for single-line events (>7storeys, do not fit azimuth) Select pure sample of atmospheric neutrinos (<5% muon contamination) zenith angle resolution: 0.8 degrees for multi-line events 3 degrees for single-line events

Neutrino Oscillations: Result 10 ANTARES K2K Super-K MINOS data (863 days): No oscillation:  2 /NDF = 40/24 (2.1%) Best fit:  2 /NDF = 17.1/21 Δm 2 = eV 2 sin 2 2  =1.00 Assuming maximal mixing: Δm 2 =(3.1±0.9) eV 2 Systematics: (Absolute normalisation free) Absorption length: ±10% Detector efficiency: ±10% Spectral index of flux: ±0.03 OM angular acceptance Submitted to PLB: arXiv: %CL contours no osc best osc ANTARES preliminary 5% error on slope vs E R /cos R

U. Katz: PINGU 11 The PINGU fact sheet PINGU geometry (more compact version also studied) Phased IceCube Next-Generation Upgrade Add 20 strings in Deep Core region Expected energy threshold at 1 GeV R&D opportunity for future developments IceCube plus further groups

PINGU Event Rates/year

Inverted vs Normal Perfect resolution 5 years: S=45.5  (f=0%) S=28.9  (f=5%) S=18.8  (f=10%)

Inverted vs Normal  E=2 GeV,  = 11.25° S=16.3  (f=0%) S=11  (f=5%) S=7.2  (f=10%)  E=3 GeV,  = 15° S=10.4  (f=0%) S=7  (f=5%) S=4.5  (f=10%)  E=4 GeV,  = 22.5° S=7.2  (f=0%) S=4.5  (f=5%) S=3.0  (f=10%) 5 years

PINGU in the Sea-> ORCA? Storey spacing 6.2m 20 storeys line height=140m Height ~3 times smaller than ANTARES (don’t need 100m gap?) Line spacing 60m -> 20m 50 lines in total? (3-5Mton instrumented volume) Toulon- incorporate inside ANTARES (help muon veto)?

ORCA 20m 25m P. Kooijman Reconstructed events per 0.1 costheta, per year 140m*140m*140m (6*6=36 strings) Bartol flux, trigger=6storeys, range inside detector, reco eff=60%

Simulations Urgently Needed Low energy reconstruction Effective area? Angular resolution? Energy resolution? Background rejection? Sea better than Ice? Studies just starting in France, Nikhef…

Strategic Aspects Face reality of funding situation Our ‘duty’ to evaluate the potential of low energy approach (alternative projects very expensive, longer time scale) Guaranteed? physics case for KM3NeT phase 1 Mass hirearchy, dark matter (Sun, GC, dwarf galaxies) neutrino astronomy at lower energy sterile?, CPV?, proton decay? Much interest from other neutrino communities (at least in France) (OPERA, MEMPhys, PINGU….) Reinforce/reinvigorate the believers of the deep sea approach A measurement of MH a solid basis from which to request additional funds needed for KM3NeT phase 2 (galactic centre sources) -can reuse the phase 1 lines Interfence with PINGU/GNO? Should proceed rapidly- document for European Strategy neutrino Roadmap (end of july)?