Neutrino Mass Hierarchy and other physics in H 2 0 (ORCA & PINGU) Aart Heijboer Nikhef, Amsterdam, KM3NeT collaboration

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1 1 Neutrino Mass Hierarchy and other physics in H 2 0 (ORCA & PINGU) Aart Heijboer Nikhef, Amsterdam, KM3NeT collaboration

2 sign unknown (vacuum) sign known 2 Mass Hierarchy matter Hierarchy important for theory, cosmology, 0νββ Measurement needed: Like Super-K But now resolve matter-effects to determine mass hierarchy vacuum

3 3 Atmospheric neutrinos A free beam of known composition (ν e, ν μ ) Wide range of baselines and energies (GeV PeV) Oscillations affected by Matter (hierarchy-dependent): Measure zenith angle and energy of upgoing atmospheric neutrinos, Careful treatment of systematics mandatory J. Coelho

4 4 Oscillation probability νe IH NH νμ Both muon- and electron-channels contribute to hierarchy asymmetry Opposite effect on anti-neutrinos: BUT differences in flux and cross-section: Φ atm (ν) 1.3 x Φ atm (anti-ν) σ(ν) 2σ(anti-ν) at low energies Cascade channel dominant. Interesting range: 5-10 GeV (in stead of TeV-PeV for astronomy) Need energy- and angular resolution. Depend on cross-section difference between nu and nubar.

5 Oscillation probability KM3NeT ARCA Building block 115 strings Both muon- and electron-channels contribute to hierarchy asymmetry Opposite effect on anti-neutrinos: BUT differences in flux and cross-section: Φ atm (ν) 1.3 x Φ atm (anti-ν) σ(ν) 2σ(anti-ν) at low energies Cascade channel dominant. ORCA building block = same DOM spacing /= 4 3 Interesting range: 5-10 GeV (in stead of TeV-PeV for astronomy) Need energy- and angular resolution. NOW Neutrino mass hierarchy Aart Heijboer Depend on cross-section difference between nu and nubar. factor 1000 lower energy -> factor 80 denser instrumentation 5

6 6 PINGU & ORCA

7 7 PINGU & ORCA I will try to combine. PINGU & ORCA Oscillation Research with Cosmics in the Abys

8 8 Letters of intent arxiv: arxiv: J. Phys. G: Nucl. Part. Phys. 43 (2016)

9 9 Letters of intent ORCA/PINGU nb: plot has many issues point is only: After Blennow Good opportunity to be the first to determine mass hierarchy + lots of other physics J. Phys. G: Nucl. Part. Phys. 43 (2016)

10 10 oscillations at ν telescopes Phys.Lett. B714 (2012) IceCube/DeepCore good atm. nu osc. measurement sterile neutrinos Tau appearance ANTARES taking data since 2008 (see talk A. Margiotta) Sees oscillations (not currently competitive measurement of atm. mixing)

11 KM3NeT/ORCA NOW Neutrino mass hierarchy Aart Heijboer 11

12 KM3NeT/ORCA Multi-site deep-sea neutrino research infrastructure Amsterdam Delft Groningen Leiden NIOZ TNO Utrecht Bamberg Erlangen Dublin Münster Sheffield Tübingen Würzburg Strasbourg Paris Mulhouse Genova Bologna Marseille Pisa Rome Barcelona Naples Granada Valencia ORCA Catania Rabat Oujda ARCA NOW Neutrino mass hierarchy Aart Heijboer Warsaw Bucharest Thessaloniki Athens Patras Moscow Nicosia 2475m 3400m Single Collaboration, Single Technology ORCA ARCA 12

13 13 KM3NeT construction started Two lines deployed; muons reconstructed Timing verified see talk G. Riccobene

14 KM3NeT/ORCA ~5.7 Mt instrumented 115 lines, 20m spaced, 18 DOMs/line 9m spaced 115 strings 18 DOMs / string 31 PMTs / DOM Total: 64k*3 PMTs 450 m Digital Optical Module x 3 PMTs Uniform angular coverage Directional information Digital photon counting Background rejection DOM spacing optimized : 9 m Depth=2475m ~210 m NOW Neutrino mass hierarchy Aart Heijboer 14

15 15 KM3NeT/ORCA Phase 1: 7 string array - demonstrate technology/detection - funded Phase 2: deploy 1 building block (115 strings) Main cable: Dec st node: Autumn 2016

16 16 KM3NeT/ORCA Total ORCA cost: 45 M DOM production ongoing 7 Strings Operational 115 Strings Full Detector ORCA Construction MH Determination

17 17

18 NOW Neutrino mass hierarchy Aart Heijboer Koskinen, neutrino

19 19 New geometry foreseen (26 strings) Substantial cost saving Less drilling (2 seasons) & reuse of drill components Less holes, cables, Reduced timeline Technology: IceCube with option to use multi-pmt Total cost : 47M$

20 20 Event topologies Track-like (νμ CC ) cascade-like (ν NC, ν e CC )

21 21 Event topologies Track-like (νμ CC ) cascade-like (ν NC, ν e CC )

22 Mass Hierarchy signature q Z (N IH -N NH )/N NH n m (tracks) n m (tracks) <5 % ORCA E,θ resolutions n e (Cascades) n e (Cascades) 10% NOW Neutrino mass hierarchy Aart Heijboer 22

23 Mass Hierarchy signature q Z (N IH -N NH )/N NH n m n m Important aspects Acceptance & background rejection Particle Identification Zenith angle resolution Energy resolution systematics n e ORCA E,θ resolutions <5 % n e 10% NOW Neutrino mass hierarchy Aart Heijboer 23

24 Atmospheric muon rejection Reconstructed track starting point KM3NeT/ORCA Preliminary KM3NeT/ORCA Preliminary Atmospheric μ (E<20 GeV) Y [m] Atmospheric v (E<20 GeV) Y [m] Atmospheric m X [m] X [m] PINGU: Identify muons in IC/DeepCore ORCA : reject muons without surrounding veto detector Reconstructed starting point of tracks PID RDF reduces background to %-level contamination NOW Neutrino mass hierarchy Aart Heijboer 24 24

25 25 Shower/Track Identification Discrimination of track-like and shower-like events via Random Decision Forest (ORCA) Fishes discriminant (PINGU) PINGU For Both, at 10 GeV: 80-90% correct identification of v e CC ~70% correct identification of ν μ CC

26 26 Effective Mass ν e ν μ ν τ NC ORCA ORCA 9m triggering, atmospheric muon rejection included Energy threshold determined by DOM spacing 9m vertical spacing -> 6 Mton@10 GeV 50% Efficiency at 5 GeV Instrumented volume reached at ~10 GeV Huge neutrino samples will be collected Events/yr: ν e CC: 17,300 ν μ CC: 24,800 ν τ CC: 3,100 NC: 5,300 Pingu: 60k V-events/yr

27 27 Zenith angle resolution cascade (v e ) Track (v μ ) PINGU PINGU ORCA: 7 (5 ) for 5(10) GeV for both channels Dominated by kinematics of neutrino interaction Largely independent of vertical spacing (ORCA)

28 28 Energy resolution Shower Track ν e 450 m ν μ ORCA ORCA Solid : nu Dashed: anti-nu Energy resolution better than 30% in relevant range Energy response close to Gaussian

29 ϴ NOW Neutrino mass hierarchy Aart Heijboer 29 Mass hierarchy analysis Pick random values for oscillation parameters and other sysematics Generate pseudo-experiments for NH, IH cases Find best-fit likelihoods L NH, L IH for the NH, IH cases (maximising w.r.t. 8/9 free parameters) Calculate the log-likelihood ratio log (L NH /L IH )

30 ϴ NOW Neutrino mass hierarchy Aart Heijboer 30 Mass hierarchy analysis Pick random values for oscillation parameters and other sysematics Generate pseudo-experiments for NH, IH cases Find best-fit likelihoods L NH, L IH for the NH, IH cases (maximising w.r.t. 8/9 free parameters) Calculate the log-likelihood ratio log (L NH /L IH )

31 ϴ NOW Neutrino mass hierarchy Aart Heijboer 31 Mass hierarchy analysis NH IH Pick random values for oscillation parameters and other sysematics Generate pseudo-experiments for NH, IH cases Find best-fit likelihoods L NH, L IH for the NH, IH cases (maximising w.r.t. 8/9 free parameters) Calculate the log-likelihood ratio log (L NH /L IH )

32 32 sensitivity PINGU Current global Fit - ~3 sigma in 4 yr over full allowed range (δ=0)

33 33 Sensitivity - ORCA ~3σ MH sensitivity in 3 years PINGU & ORCA very similar The combination of NH and upper octant of θ 23 would significantly improve sensitivity For IH, sensitivity is essentially independent of θ 23 The value of δ cp has small but nonnegligible impact on sensitivity 3 yrs Best case scenario (NH and θ 23 =48 ) could achieve >5σ by mid 2021 (1.5 years)

34 34 Mass hierarchy Systematics ORCA PINGU Measurement will require tight control of systematics, but: Studies advanced and fully included in results. Systematics limited (ΔM 2, θ 23 ) but no show-stoppers.

35 35 Measurement: Δm 2 32 and sin 2 θ 23 High statistics and excellent resolution Measure Δm 2 32 and sin 2 θ 23 Competitive with NOvA and T2K projected sensitivity in 2020 Achieve 2-3% precision in Δm 2 32 and 4-10% in sin 2 θ 23 Normal Hierarchy Inverted Hierarchy 1 sigma contours T2K 2015 T2K 2020 NOvA yrs MINOS KM3NeT/ORCA

36 36 Measurement: Δm 2 32 and sin 2 θ 23 High statistics and excellent resolution Measure Δm 2 32 and sin 2 θ 23 Competitive with NOvA and T2K projected sensitivity in 2020 PINGU Achieve 2-3% precision in Δm 2 32 and 4-10% in sin 2 θ 23 Inverted Hierarchy Normal Hierarchy Inverted Hierarchy 1 sigma contours T2K 2015 T2K 2020 T2K 2015 NOvA 2020 T2K 2020 NOvA yrs MINOS KM3NeT/ORCA MINOS KM3NeT/ORCA

37 Indirect Detection of Dark Matter χ Relic WIMPs gravitationally trapped via elastic collisions (Sun, Earth, Galactic Center) X X X X X v Earth <E v > ~ M x /3 ORCA Spin Dependent Spin Independent NOW Neutrino mass hierarchy Aart Heijboer ORCA 3 years - tracks+showers 37

38 38 Nu tau appearance (PINGU) Hard to separate v τ from v e (and nc) event-by event But can check that for the expected pattern in E vs cos θ plane Check unitarily of PMNS matrix

39 39 Non standard interactions

40 40 Non standard interactions IceCube/Deepcore present result With 1 year of data, ORCA (&PINGU) can set Limits < 0.1 Current limits Rept. Prog. Phys. 76, (2013)

41 Sterile neutrinos the dominant effect of adding a ev scale sterile neutrino would be the suppression of v μ to v τ oscillation at ~20 GeV. ORCA sensitive to U τ4 2 values 5x smaller than current limits set by Super-Kamiokande 41

42 42 conclusions Both IceCube and KM3NeT have viable Low-energy program PINGU & ORCA: very comparable in sensitivities ORCA: adopted as part of KM3NeT, partially funded construction has started. completion by 2020 feasible PINGU: New geometry & shorter timeline. Can be implemented in 5 yrs. Mass Hierarchy measurement is challenging but feasible 3σ in 3-4 year; much better if NH and sin 2 θ 23 >0.5 Many systematics already studied and included Much other Physics: Measurement of Δm 2 32 and sin 2 θ 23 Sterile neutrinos Non-standard interactions Indirect Dark matter Earth tomography PMNS unitarity / tau appearance