Particle Physics and Astrophysics with Large Neutrino Detectors

1. Particle Physics and Astrophysics with Large Neutrino Detectors Irina Mocioiu Pennsylvania State University

2. Experiments • IceCube/DeepCore: Cherenkov light in ice (South Pole) • PINGU • Antares: Cherenkov light in water (Mediteraneen) • Pierre Auger: air showers (Argentina) • radio Cherenkov: higher energy • large underground neutrino detectors … Real data! + more to come

3. Sources • some “guaranteed” high energy neutrinos: GRB cosmic rays AGN • Maybe: • dark matter annihilation • topological defects • cosmic strings • … Exactly how many? Where? What energies? CMB

4. Lessons for particle astrophysics weak interactions • access to dense, violent environment • test mechanism powering astrophysical sources • cosmic ray acceleration processes • cosmic ray propagation and intergalactic backgrounds • … Lessons for particle physics high energies, beyond those accessible in colliders, etc. weak interactions • neutrino interaction cross-sections (in Standard Model!) • neutrino properties • new interactions/particles • dark matter • … complementary to photons and charged particles

5. Sources • flavor composition • mostly decay • not always: • neutron decay, energy thresholds, energy losses, • matter effects, magnetic fields • energy dependent flavor ratios • depend on neutrino and source properties Propagation: • neutrino oscillations over long distances • decay + maximal mixing: • different initial state: three flavor mixing important • non-standard neutrino properties: decay, additional interactions, extra • neutrinos, … • change flavor composition/energy spectrum Interactions: • in SM: cross section extrapolations, energy losses, flavor • beyond SM: new interactions, LIV, new particles, dark matter, …

6. How to do it? • measure all you can • take into account everything you know/can think about • Identify the right observables • energy distributions • angular distributions • flavor compositions • better detector techniques • smart tricks, unique signatures • very good simulations • correlations with other observables: photons, protons, etc. • can distinguish particle physics from astrophysics effects • learn about both

7. Pastpr, Nu 2012

8. IC 59 diffuse Sullivan, Nu 2012

9. diffuse limits Cascades: 14 events; expected bkgd 11.6

10. highest energies, gamma horizon very limited

11. IceCube sensitivity greatly improved Ishihara, Nu 2012

12. IceCubeGRB search Sullivan, Nu 2012 Nature 484, 351 (2012)

13. Excluded models? Not yet! Probing interesting parameter space Hummer, Baerwald, Winter (2012) He, Liu, Wang, Nagataki, Murase, Dai (2012) • Detailed analysis • Energy dependence in spectra -> order of magnitude reduction in nrs

14. Outlook • Neutrino telescopes now real: data! • Getting better • Just starting to get interesting now! • High energy astrophysical neutrinos • smoking gun for hadronic processes • (few events for point source) • need detailed analysis for data interpretation

15. IceCube Deep Core • initial motivation: look for neutrinos • fromgalactic sources, dark matter • annihilation • galactic center is above horizon at South Pole • need to reduce large cosmic muon background • coverage • look at down-going events, • study galactic sources, galactic center • low energy threshold: opens the • 10 -- 100 GeV neutrino energy range • overlap with Super-Kamiokande at low • energy and with IceCube at high energies

16. Atmospheric neutrinos Super-Kamiokande • expect: at low energies IceCubeDeep Core • steep energy spectrum ( ) • fluxhard to measure at high energies • Background to many searches • lots of them • > 50,000 events per year! • somebody’s background is somebody else’s signal • remember: • solar neutrinos: solar physics, atmospheric neutrinos: proton decay

17. Three-flavor neutrino oscillations • Three-flavor mixing matrix (in terms of Euler angles) • We want to measure hierarchy (sign of ) CP violating phase octant Large effort to build new accelerator/reactor experiments beams: great control/precision; long time scales/high cost

18. Neutrino oscillations in the IceCube Deep Core tracks: -like fully contained events Angular distribution: • atmospheric flux normalization • + main oscillation signal ( ) • + matter effects ( , hierarchy, CP) Energy distribution: • neutrino oscillations • atmospheric neutrino flux • Earth density profile ICDC physical mass: Effective mass in our analysis: (energy dependent) O. Mena, I. M., S. Razzaque (2008); G. Giordano, O. Mena, I. M. (2010) E. Fernandez-Martinez, G. Giordano, O. Mena, I. M. (2010)

19. ICDC atmospheric neutrinos E. Fernandez-Martinez, G. Giordano,O. Mena, I. M.(2010) Observable energy: Measure main oscillation parameters • IceCube Deep Core: • very large statistics • contribution from multiple peaks Present: : MINOS : Super-Kamiokande

20. Normal versus inverted mass hierarchy • fit to discriminate between normal and inverted hierarchy O. Mena, I. M., S. Razzaque (2008) 1 0.8 0.6 0.4 0.2 0 25 15 5 10 20 E (GeV) • much better now, with known and large

21. Presently allowed values: (MINOS) (Super-Kamiokande) Observable energies of 5 to 50 GeV 10 energy bins, 4 angular bins vs. 1st energy bin, 1 angular bin + 9 energy bins, 4 angular bins vs. Exclude first 2 energy bins: 8 energy bins, 4 angular bins IceCube Deep Core: vs vs completely free

22. IceCube Deep Core • Expected allowed • regions depend on • the true values of • the parameters and • control of systematic • uncertainties • Neutrino oscillations: now important physics goal of ICDC -> PINGU

23. How about cascades? • CC interactions: • NC interactions: • decay Earth diameter • Looking for helped by: high energy (tau threshold effects small) background low: oscillations

24. Tau cascade rates • or hadrons large • present world sample of events: • 5(9) DONUT + (2) (OPERA) • Super-Kamiokande (after 15 years): • high statistics interactions • direct evidence for appearance • interaction cross-section • non-standard interactions of • experience with cascade detection • ICDC has already observed cascade events in the first small data sample

25. Mass Hierarchy in PINGU Akhmedov, Razzaque, Smirnov, 2012 in 5 years, depending on reconstruction • systematics • very general analysis, no details • DIS only • full analysis: likely better outcome! Mass Hierarchy inICDC Agarwalla, Li, Mena, Palomares-Ruiz , 2012

26. more physics than ICDC • lower energy: • better “shape” of first peak • (precision) • secondary peaks -> • two mass scales contribute • (CP violation+matter effect) • analysis more involved than ICDC • better reconstruction/resolution • atmospheric flux: transition between mu+pi and pi: • -> flavor and energy dependence • cross-sections: many contributions • -> energy dependent uncertainties • -> limited use of full kinematics: very useful with • DIS in ICDC • -> larger systematics/more work + outside input potentially • very (cross section measurements, etc.) PINGU

27. Whatphysics? • Input from reactors, etc. • Precision measurement of main oscillation parameters • Above 10 GeV – nu tau cascades • Matter effects – hierarchy • few GeV – interference of two mass scales – CP phase • theta_23 octant • non-standard interactions – matter effects • very useful information in combination with long baseline exp. What is needed: • (Some) angular reconstruction: 3-4 bins sufficient • Energy measurement: important to have few GeV and > 10GeV • Flavor ID?

28. Atmospheric Neutrino Oscillations • Large energy range: 100 MeV - 100 GeV • Many baselines: 15 km – 13000 km cover large parameter space Long Baseline Neutrino Oscillation Experiments • Fixed distance • Good energy measurement • Well known flux (near detector) good parameter determination • Complementary information • Consistency checks very important • Surprises? • Is the three flavor oscillation picture the entire story? • Are weak interactions the entire story?

29. Sterile Neutrinos • Model dependence: • 3+1 (6 angles), 3+2 (10 angles), 3+2+CP violation • angles: sterile mixing with , , • possible affect and differently • If one present, expect the other • No one to one correspondence between LSND/MiniBooNE (mu-e) and IceCube observations (mu-mu,mu-tau) • Can constrain or discoveroscillations at • high mass scale for angles in the general range • probed by MiniBooNE/LSND • Cannot directly confirm/rule out • MiniBooNE/LSND sterile nu interpretation

30. Sterile Neutrinos • Cannot directly confirm/rule outMiniBooNE/LSND sterile nu interpretation • except in specific/predictive models: 1205.5230 • Minimal 3+2 neutrino model • - 4 massive mass eigenstates, 1massless • - 2 additional, right handed Weyl fields • - 4 mixing angles + 3 phases • Standard parameters+ 45angle+one extra phase • - distortion of spectrum • - large tau appearance D. Hollander, I.M.

31. Non-Standard Interactions (NSI) • Expected in connection with mass generation models, • sterile neutrinos, etc. • Parameterize our ignorance by most general form and try • to constrain from data Matter effects in neutrino oscillations Very weak constraints in the sector

32. εeτ - εττ Preliminary Large correlations/degeneracy between parameters W. Wright, I.M.

33. Remember some history • 1980’s: large detectors looking for proton decay, • grand unification, etc.; atmospheric neutrinos arebackground • atmospheric neutrino problem Super-Kamiokande (1998) Atmospheric neutrinos: many uncertainties Beamline Proposals: MINOS 1995 OPERA 1998 ICARUS 1993 (detector), 1996 (neutrino oscillations)

34. Long Baseline Neutrino Oscillation Experiments • K2K (2000): confirmation of neutrino oscillations • MINOS (2006): energy spectrum, best mass difference measurement • OPERA: (2010) first tau candidate neutrino detection • ICARUS: taking data • T2K: taking data -> precision measurements, sub-dominant effects • NOVA: under construction

36. Outlook • IceCube Deep Core detector already taking data ! • built to look for galactic sources, dark matter • someone’s background can be someone else’s signal • experiments take a very long time to construct/operate • atmospheric neutrinos: huge statistics, many energies/distances • use the data we already have and get the most of it! • PINGU: huge, cheap, fast • long baseline experiments: fixed baseline, limited energy range • atmospheric neutrinos: many baselines, large energy range • complementary information • combined data: consistency checks • expect SURPRISES!