Atmospheric Neutrinos Stefan SldnerRembold University of Manchester 19

Atmospheric Neutrinos Stefan Söldner-Rembold University of Manchester 19 December 2013 1

Atmospheric Neutrinos • Provide complementary results with other neutrino sources. • Increase precision of global fits of neutrino parameters. • Tools to search for new physics. 19 December 2013 Nu. Phys 2013 - Söldner-Rembold 2

Three Questions ar. Xiv: 1312. 2878, see talk by E. Lisi 19 December 2013 1) Is θ 23 mixing maximal and which is the right octant ? 2) Is the mass hierarchy normal or inverted ? 3) Is δCP > 0 ? Nu. Phys 2013 - Söldner-Rembold 3

Neutrino Propagation in the Earth Preliminary Reference Earth Model ν ν ν Atmospheric neutrinos interact with Earth’s mantle and core. - MSW effect alters oscillation properties (energy, electron density, MH and flavour dependent). - “parametric enhancement” at Core/Mantle interface. 19 December 2013 Nu. Phys 2013 - Söldner-Rembold 4

MSW Effect +: neutrinos -: anti-neutrinos CC interactions Effective mixing angle in matter: Resonance condition for - neutrinos in normal hierarchy. - anti-neutrinos in inverted hierarchy. depends on energy and density profile. 19 December 2013 Nu. Phys 2013 - Söldner-Rembold 5

MSW Effect in the Earth SK cos θ Energy Distortions for cos θ < -0. 5 and at 10 Ge. V caused by MSW effect 19 December 2013 Nu. Phys 2013 - Söldner-Rembold Energy ar. Xiv: 1310. 6677 6

Neutrino Energies 10 Me. V 100 Me. V 1 Ge. V 100 Ge. V 1 Te. V Deep Core Super-K Borexino Kam. LAND Double Chooz Daya Bay SNO 10 Te. V 100 Te. V 1 Pe. V Ice. Cube 10 Pe. V ANITA PINGU Fill gap in intermediate energy region in region of MSW resonance effects. Several future experiments: INO, PINGU, Hyper-K, LBNE. . 19 December 2013 Nu. Phys 2013 - Söldner-Rembold 7

Super-Kamiokande Water Cherenkov Detector located in Mozumi Mine, Kamioka, Japan 50, 000 t of water 11, 146 PMTs 19 December 2013 First observation of muon-neutrino deficit due to oscillations in 1993 Nu. Phys 2013 - Söldner-Rembold 8

Super-Kamiokande (SKI-IV) red: un-oscillated blue: best oscillation fit 19 December 2013 Nu. Phys 2013 - Söldner-Rembold 9

ντ Appearance (SK) Phys. Rev. Lett. 110, 181802 (2013) fitted signal in grey Unambiguous evidence for oscillations (νμ ντ) since not present in source. 2806 day running period. Energy threshold E > 3. 5 Ge. V. Reconstruct hadronic tau decays using neural network. 3. 8 standard deviation significance (complements OPERA result) 19 December 2013 Nu. Phys 2013 - Söldner-Rembold 10

MINOS see presentation by C. Backhouse 5, 400 ton Far Detector Alternating layers of steel calorimeter and plastic scintillator. Magnetized for charge identification 19 December 2013 Nu. Phys 2013 - Söldner-Rembold 11

MINOS Beam/Atmospheric Data 19 December 2013 Nu. Phys 2013 - Söldner-Rembold 12

MINOS Combined Analysis 19 December 2013 Nu. Phys 2013 - Söldner-Rembold 13

Future Experiments 19 December 2013 Nu. Phys 2013 - Söldner-Rembold 14

Indian Neutrino Observatory Located in Madurai City, Tamil Nadu 19 December 2013 Nu. Phys 2013 - Söldner-Rembold 15

ICAL@INO Iron sampling calorimeter (ICAL) with Resistive Plate Chamber (RPCs) as active component. 50, 000 t of iron. 1. 3 -1. 5 T magnetic field for charge identification and momentum reconstruction Pre-project activities approved. 19 December 2013 Nu. Phys 2013 - Söldner-Rembold 16

INO Sensitivity sin 2 2θ 13 = 0. 12, 0. 1, 0. 08 and sin 2θ 23 = 0. 5. 19 December 2013 Nu. Phys 2013 - Söldner-Rembold ar. Xiv: 1303. 2534 17

PINGU Extension of Ice. Cube located at the South Pole. 40 strings with 60 PINGU Digital Optical Modules (PDOMs) per string. Design still being optimised. In-fills Deep. Core in clearest ice at bottom centre of Ice. Cube. Effective mass about 3 Mt for energies > 5 Ge. V 19 December 2013 Nu. Phys 2013 - Söldner-Rembold 18

PINGU μ direction 4. 4 Ge. V νµ Nγ: circle size tγ: colour PINGU Digital Optical Module: HQE PMT, electronics, pressure vessel. Very similar to Ice. Cube DOM. 19 December 2013 Nu. Phys 2013 - Söldner-Rembold 19

MH Signature Energy Need good energy and angular resolution. NH IH cos(θ) 19 December 2013 + = Pattern A + = Pattern B Diagonals are lines of constant L/E Nu. Phys 2013 - Söldner-Rembold 20

“Distinguishability” Parametrized reconstruction, PID: tracks Parametrized reconstruction, PID: cascades With realistic particle identification No systematics 19 December 2013 Nu. Phys 2013 - Söldner-Rembold 21

PINGU Consistent results from different statistical techniques, includes systematics (mainly energy scale, cross sections). First vs second octant First octant only Expect 1. 75 standard deviations after first year of data. Reach 3 standard deviations in roughly 3 years. 19 December 2013 PINGU currently being considered by P 5 in the US – will possibly be part of a larger NSF facility at South Pole. Nu. Phys 2013 - Söldner-Rembold 22

KM 3 Ne. T/ORCA - 1000 optical modules with 6 m spacing, over 50 strings. - Semi random pattern in a circular footprint. - Mean distance between strings is 20 m. - Instrumented volume: 1. 8 Mton not being pursued ? 19 December 2013 Nu. Phys 2013 - Söldner-Rembold 23

LBNE Far Detector needs to be underground for atmospheric neutrino detection. Data taking to start around 2025 see talk by R. Wilson Liquid Argon TPC 19 December 2013 Argo. Neu. T Nu. Phys 2013 - Söldner-Rembold 24

LBNE 35 kt x 10 yrs = 350 kt-yrs 19 December 2013 Nu. Phys 2013 - Söldner-Rembold ar. Xiv: 1307. 7335 25

LBNE ar. Xiv: 1307. 7335 19 December 2013 Nu. Phys 2013 - Söldner-Rembold 26

Hyper-Kamiokande ar. Xiv: 1109. 3262 8 km south of SK Total mass: 1 Mt Fiducial mass: 560 kt (25 times SK) 99, 000 inner detector PMTs (20’’) Data taking expected to start 2023 19 December 2013 Nu. Phys 2013 - Söldner-Rembold 27

Sensitivity to Mass Hierarchy 10 years of data Lowest sensitivity for first octant. ar. Xiv: 1309. 0184 19 December 2013 Nu. Phys 2013 - Söldner-Rembold 28

Sensitivity to θ 23 Octant 10 years of data 19 December 2013 Nu. Phys 2013 - Söldner-Rembold 29

Mass Hierarchy Bottom Line plus Hyper-K with > 3 sigma around 2033. 19 December 2013 Nu. Phys 2013 - Söldner-Rembold ar. Xiv: 1311. 1822 30

Summary • Atmospheric neutrinos are a unique source of information, complementary to neutrino long-baseline beam results. • Several next-generation experiments based on (frozen) water (PINGU, Hyper-K), liquid argon (LBNE) or iron sampling calorimeters (INO) are currently being designed. • These experiments have potential to determine neutrino mass hierarchy and to constrain θ 23 , providing, among others, important input for δCP determinations. 19 December 2013 Nu. Phys 2013 - Söldner-Rembold 31