Studies on PINGU’s Sensitivity to the Neutrino mass Hierarchy P. Berghaus, H.P. Bretz, A. Groß, A. Kappes, J. Leute, S. Odrowski, E. Resconi, R. Shanidze DPG-Frühjahrstagung Dresden, March 7, 2013

2 Alexander Kappes | DPG-Frühjahrstagung, Dresden | | The IceCube neutrino observatory Completed since Dec ‣ IceTop Air shower detector ‣ IceCube 86 strings (5160 PMTs) Instrumented volume: 1 km 3 ‣ Deep Core densely instrumented central region (8 strings) m m

3 Alexander Kappes | DPG-Frühjahrstagung, Dresden | | DeepCore experience Veto atmospheric muons ‣ Containment cuts → reduction by 10 3 ‑ 4 (signal efficiency 10 ‑ 20%) ‣ Further improvements can be expected Reconstruct low-energy events (direction, energy) ‣ Measurement of Δm 2 and sin 2 (2θ) ‣ Energy information not used yet ‣ Significant improvements expected (systematics crucial) cut level Example: IC79 DeepCore study

4 Alexander Kappes | DPG-Frühjahrstagung, Dresden | | From IceCube via DeepCore to PINGU IceCube (1 GTon) DeepCore O(10-100) MTon PINGU O(1-10) MTon E. Resconi IceCube Instrumented volume: 1 Gt Average DOM density: 5×10 ‑ 6 m ‑ 3 Target energy: ≳ 100 GeV DeepCore Instrumented volume: 10 ‑ 100 Mt Average DOM density: 20×10 ‑ 6 m ‑ 3 Target energy:10 GeV ‑ 100 GeV PINGU Instrumented volume: 1 ‑ 10 Mt Average DOM density: > 200×10 ‑ 6 m ‑ 3 Target energy:1 GeV ‑ 20 GeV PINGU talks at DPG: MoT109.7 OM development Mi T89.8,T89.9 Oscillations / matter effects Do T104.5 Reconstruction

5 Alexander Kappes | DPG-Frühjahrstagung, Dresden | | PINGU What is PINGU? ‣ Precision IceCube Next Generation Upgrade ‣ 20+ additional strings with DOMs each in lower detector center Preliminary timeline Proposal to funding agencies design, manufacture and test hardware drill preparations first deployment finish deployment (20 strings) first set of cables/DOMs shipped to Pole start data taking Height 300 m

6 Alexander Kappes | DPG-Frühjahrstagung, Dresden | | PINGU: Hardware Minimize cost and risk ‣ Reduce (50%) power consumption for each single PINGU-DOM ‣ Parts kept: sphere, penetrator, PMT, collar, gel, harness, HV generator and base, quad cable technology ‣ Parts under new development: digitizer (ADC), mother board, flasher (LED), FPGA logic, power supply ‣ Upgrade: DAQ, down-hole cable, surface electronics Cost reduction ~30% compared to IceCube also other ideas for future detectors under development → T109.7 (Mo.) L. Classen

7 Alexander Kappes | DPG-Frühjahrstagung, Dresden | | PINGU: Hardware charge ratio scattering coefficient [1/m] H.P. Bretz preliminary m -1

8 Alexander Kappes | DPG-Frühjahrstagung, Dresden | | PINGU: Physics topics ‣ Precision measurement of oscillation parameters (sin θ 23, Δm 23 2 ) (→ T89.8 Wed. K. Frings) ‣ Neutrino mass hierarchy → this talk ‣ Low-mass WIMPs ‣ MeV neutrinos from Galactic supernovae

9 Alexander Kappes | DPG-Frühjahrstagung, Dresden | | Neutrino Oscillations: The MSW effect ‣ Electron neutrinos: Modification of oscillation parameters while traveling through matter ‣ For two neutrino mixing: atomic shell e‑e‑ e‑e‑ W νeνe νeνe e‑e‑ e‑e‑ W‑W‑ νeνe νeνe NeutrinoAnti-Neutrino electron density sign ≙ mass hierarchy

10 Alexander Kappes | DPG-Frühjahrstagung, Dresden | | PINGU: Mass hierarchy Note: only neutrinos here NH IH

11 Alexander Kappes | DPG-Frühjahrstagung, Dresden | | PINGU: Mass hierarchy Note: neutrino telescopes inherently insensitive to ν ↔ ν Perfect resolution ΔN(IH ‑ NH) / √N(NH) [PINGU 1 yr] Akhmedov et al., arXiv:

12 Alexander Kappes | DPG-Frühjahrstagung, Dresden | | PINGU: Sensitivity to mass hierarchy Significance crucially depends on ‣ selection efficiency ‣ zenith / energy resolution (→ talk R. Shanidze) ‣ systematic uncertainties Akhmedov et al., arXiv:

13 Alexander Kappes | DPG-Frühjahrstagung, Dresden | | PINGU: Mass hierarchy ‑ systematic uncertaintiesExternal PINGU specific Primary CR flux (AMS, BESS, …) M. Sajjad AtharM. Sajjad Athar, M. Honda et al., DOM efficiency improved in-situ calibrations Geomagnetic field, interaction model M. Sajjad AtharM. Sajjad Athar, M. Honda et al., Ice optical properties drill water purification, improved in-situ calibration Atmospheric neutrinos zenith, energy, composition M. Sajjad AtharM. Sajjad Athar, M. Honda et al., Background contamination improved reconstruction Earth Profile (PREM, …) under study (→ T 89.9 (Wed) S. Coenders) Neutrino Interaction cross section starting with GENIE under study Mixing parametersdegeneracies

14 Alexander Kappes | DPG-Frühjahrstagung, Dresden | | Summary ‣ DeepCore has demonstrated IceCube’s low-energy (10th GeV range) capabilities ‣ PINGU aims at lowering the energy threshold to ~1 GeV → prime target: neutrino mass hierarchy ‣ Working hard on overcoming challenges: reconstruction, systematic uncertainties, degeneracies with other oscillation parameters ‣ Availability of full sensitivity / feasibility study planned for this Summer