Particle Physics: Status and Perspectives Part 7: Neutrinos Manfred Jeitler

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3 neutrino oscillations  old idea: in analogy to K 0 -    oscillations, neutrinos might also change their flavor  “mass eigenstates” would not be “Weak eigenstates”  first put forward by Bruno Pontecorvo (1957, 1967)  “solar neutrino deficit”: too few ν e observed from sun  theory seemed convincing because of known solar energy  basic process is  p + p  d + e + + ν  over long time, only one experiment (“Homestead mine”, Ray Davies)

4 The Homestake gold mine (South Dakota, USA) 1889 today

5 The Homestake solar neutrino detector (1500 m under ground)

6 Raymond Davis Nobel prize 2002

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9 neutrino oscillations

10 neutrino oscillations

11 neutrino mixing  both electron-neutrinos and muon-neutrinos mix  solar neutrino deficit: too few ν e from sun  atmospheric neutrino deficit: too few ν μ from atmosphere  cosmic radiation creates pions  π +/-  μ +/- ν e  strong mixing  much stronger than in quark sector  low masses  Δm 2 solar  eV 2  Δm 2 atmos  2  eV 2  we know only mass differences, not masses themselves  origin of neutrino mass?  beyond Standard Model!  “see-saw” mechanism?

12 the Superkamiokande neutrino detector (Japan)

13 atmospheric neutrinos

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17 Long-baseline experiments

Messengers from the Universe  Photons currently provide all information on the Universe. But they are rather strongly reprocessed and absorbed in their sources and during propagation. For E g > 500 TeV photons do not survive journey from Galactic Centre.  Protons+Nuclei: directions scrambled by galactic and intergalactic magnetic fields. Also, for E pr >20 21 eV they lose energy due to interaction with relict radiation (GZK-effect: Greisen-Zatsepin- Kuzmin limit).  Neutrinos have discovery potential because they open a new window onto the universe W49B SN Crab E Cas A  P+Nuclei

M. Markov: High Energy neutrino detection in natural transparent media (ocean water, ice): O(km) long muon tracks  5-15 m Charged Current (CC)  Electromagnetic & hadronic cascades ~ 5 m CC e  + Neutral Current

log(E 2  Flux) log(E/GeV) TeV PeV EeV pp core AGN p  blazar jet GZK GRB (W&B) WIMPs WIMPsOscillations Underground Underwater Radio,Acoustic Air showers Microquasars etc.

A NT200+/Baikal-GVD (~2015) N N KM3NeT (~2014) /IceCube Amanda/IceCube (now) (now) ANTARES NEMO NESTOR

Schematic view on the deep underwater complex NT Neutrino Telescope NT200 7-hydrophysical mooring 5-sedimentology mooring 12-geophysical mooring acoustic transponders 1-4 cable lines Anchor Buoy

NT200 running since strings with 192 optical modules, - 72m height, - R=21.5m radius, -1070m depth, Vgeo=0.1Mton  effective area: S >2000 m 2 (E  >1 TeV) Shower Eff Volume: ~1 Mt at 1 PeV

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