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Neutrinos as probes of ultra-high energy astrophysical phenomena

Neutrinos as probes of ultra-high energy astrophysical phenomena. TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: A A A A A A. Neutrino sources. 10-40 MeV. GeV – 10sTeV. up to 10 MeV. J. Becker Phys. Rep. 458. IceCube detector. Detection Principle.

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Neutrinos as probes of ultra-high energy astrophysical phenomena

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  1. Neutrinos as probes of ultra-high energy astrophysical phenomena TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AAAAAA

  2. Neutrino sources 10-40 MeV GeV – 10sTeV up to 10 MeV J. Becker Phys. Rep. 458

  3. IceCube detector

  4. Detection Principle

  5. “Cascades” • Cerenkov radiation is also emitted from all particles in a particle shower • The shower length is less than 5m (for E < 5eV) • Due to scattering the Cerenkov light will have an isotropic distribution around 25m from the shower

  6. Neutrino interactions in the ice

  7. Neutrino signature in IceCube

  8. Backgrounds

  9. Cosmic rays – source of atmospheric neutrinos and muon background detected by IceCube

  10. IceCube Diffuse Neutrino Searches • Look for neutrino events at high energy, above the falling atmospheric neutrino spectrum. •  • signal looks for upward going tracks • Cascade events (CC e and t , NC e,,t) Conventional atmospheric Prompt atmos astrophysical

  11. IceCube Point Source Searches • Look for a signal correlated in direction with astrophysical objects (and time if transient object)

  12. Gamma Ray Burstneutrino search • GRBs - Short, intense, eruptions of high energy photons, with afterglow detected in X-ray to radio • Bimodal distribution of burst times interpreted as two different progenitor models • Long duration bursts result from collapse of massive star to black hole • GRB030329 observed by HETE II linked to type 1C Supernova • Long duration bursts in galaxies with young massive stars • Short duration bursts result from collision of some combination of black holes and neutron stars • GRB050509B observed by Swift with limited afterglow • Appears to have occurred near a galaxy with old stars

  13. GRB neutrino search • GRBs - plausible origin of ultrahigh energy cosmic rays • Particles accelerated through Fermi mechanism • Protons and photons interact • Leads to neutrinos via pion and muon decay

  14. No neutrinos... NatureVol 484, 351 (2012) 2008-9 data: 117 northern sky GRBs 2009-10 data: 98 northern sky GRBs and 85 southern sky GRBs • Model-dependent analysis:Found no events within time-window and within 10° of GRB position • Also model-independent analysis (larger time window with no specific energy weighting) two low significance events with IceTop hits consistent with being background

  15. IC59Diffuse  Search (1.8 sigma evidence for non-atmospheric) 348 days livetime, 21943 events

  16. IC40 Cascade Search (2.8 sigma)

  17. GZK neutrino search

  18. Greisen–Zatsepin–Kuzmin limit (GZK limit) • At 5 × 1019 eV cosmic rays interact with the microwave background photons through the delta resonance • This reduces the cosmic rays of this energy or higher zero (for sources greater than 50 MpC)

  19. Origin of the ultra-high energy cosmic rays? ? 1012eV = TeV 1015eV=PeV 1018eV = EeV

  20. GZK neutrino search Cosmic ray spectrum E>1018eV

  21. Neutrino sources 10-40 MeV GeV – 10sTeV up to 10 MeV J. Becker Phys. Rep. 458

  22. GZK neutrino search

  23. Earth opaque for neand nmE>1 EeV

  24. Summary • IceCube is detecting neutrinos beyond the expectation from atmospheric neutrinos...Inconsistent at 4.3σ with standard backgrounds

  25. PINGU • The Precision IceCube Next Generation Upgrade • A more densely packed inner detector

  26. PINGU-aims to determine the mass hierarchy in < 5 years • Oscillation through MSW and parametric effect* due to density transition at earth core/mantle*

  27. Muon neutrino survival probability

  28. “Distinguishability” metric

  29. Neutrinos and Supernova

  30. Supernova Mechanisms • Thermonuclear supernova: type Ia • Runaway burning initiated by binary companion • Used in cosmology as standard candles • Core-collapse supernova: type II,Ib,IcM > 8 Msun • Collapse of iron core in a massive star • MeV neutrinos from proto-neutron star • (GRBs massive version of these...?)

  31. Supernova Sequence ~107 km Slide credit: G Raffelt

  32. Supernova Sequence Slide credit: G Raffelt

  33. Supernova Sequence Slide credit: G Raffelt

  34. Supernova Sequence Slide credit: G Raffelt

  35. Neutrinos from: • Short neutronisation burst (tens ms) from electron capture • Accretion (10s to 100s ms) dominated by electron flavour neutrinos • Cooling as the gravitational potential energy of the collapsing core is released (tens s),pairs dominate neutrino production • References:

  36. Supernova 1987A:

  37. What did we learn:

  38. What could we learn: • Much about the physics of supernova – information about shock waves, accretion, cooling, possible formation of exotic matter, and further collapse to a black hole imprinted on the neutrino spectrum. • Neutrino sector information: mass and oscillation parameters, hierarchy • Other particle physics as energy loss constrains other exotic channels • References: • References:

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