A super-dense ice detector for SN neutrinos and proton decay at the South Pole

1. Marek Kowalski A super-dense ice detector for SN neutrinos and proton decay atthe South Pole Marek Kowalski, Bonn University

2. Marek Kowalski MICA - Mega Ton Ice Cherenkov Array IceCubeDeepCorePINGUMICA So far, MICA is an idea and not yet a well defined project. Today I highlight two novel aspects: - Proton decay - Extra galactic SN detection

3. Marek Kowalski Why South Pole? • IceCube „lab“ has been completed – significant (positive) experience with deployment & operation • Very clear, pure & stable detection medium • A possible cost-effective option for Megaton instrumented volume with 10 MeV threshold

4. Marek Kowalski Proton decay The signal: p➝π0+e+ MICA - 5 Mton x 5 years Hyper-Kamiokande _l Letter of Intent 2011

5. Marek Kowalski Proton decay The signal: p➝π0+e+ ➝γ+γ+e+ MICA - 5 Mton x 5 years Hyper-Kamiokande _l Letter of Intent 2011 Super-Kamiokande - three ring event

6. Marek Kowalski Proton decay The signal: p➝π0+e+ SK rate of atmospheric neutrino background: 1.6 events/(Mton year) SK I (before accident): 40% surface coverage SK II: 20% coverage  simiar background But what about < 20 %?

7. Marek Kowalski Proton decay The signal: p➝π0+e+ SK rate of atmospheric neutrino background: 1.6 events/(Mton year) SK I (before accident): 40% surface coverage Figure by T. DeYoung SK II: 20% coverage  simiar background But what about < 20 %?

8. Marek Kowalski Proton decay Ring geometry Proton decay simulation Realistic background study required! Figure by C. Kopper

9. Detectinglow-energy Supernova neutrinos • Current neutrino telescopes are • sensitive to galactic SNe, such as SN 1987A: • 1-2 SN per century 5 (or more) Mton needed to observe extragalactic SNe on annual basis

10. SN burstneutrinos • Directly probe of core collapse, e.g. black hole vs neutron star • Rate of SNe (e.g. no dust obscuration) • Neutrino-mass hierarchy & QCD phase transition. • Early triggers for follow-up to catch very early phase. • Gravitational detectors: Coincident search ~3000 times more significant. ... SN 1987A

11. Marek Kowalski GravitationalCollapse: Black Hole vs Neutron Star dark SNe from BH formation NS formation: TBP-Model LL-Model Yang, Lunardini, arXiv:1103.4628v1

12. Marek Kowalski Baseline layout • 61 strings, 300 m long, 300 modules on each string, each module ~7.4 (5.4) std. (HQE) IceCube DOMs • let string spacing float in optimization • Detector location: Deep ice (2150 m – 2450 m) Trigger on≥ 5 Photon Hits

13. Marek Kowalski Effective mass

14. Marek Kowalski SN Detection Probability Trigger on SN event with ≥3 neutrinos

15. Marek Kowalski SN Detection Rate • Expected SN rate in local Universe:

16. Marek Kowalski SN Detection Rate ∫ x = *Dark SN rate assumed to be 10% of total

17. Marek Kowalski Backgrounds

18. Marek Kowalski Backgrounds For 1 fake SN per year: • fmax = 4 mHz for Δt = 1 s • fmax = 0.9 mHz for Δt = 10 s Solar neutrinos to be further suppressed by direction and/or energy cut But: Background very interesting by itself! (e.g. G-modes of the sun)

19. Marek Kowalski Summary • The South Pole offers pristine environment for a Mton low-energy neutrino detector • Dense array can reach 10 MeV threshold @ 10 Mton, with enormous scientific opportunities Examples: galactic SNe and proton decay • R&D towards larger, low noise sensors required to make the project feasible