Astrophysical Neutrinos

Neutrinos as probes

HQL, Munich, October 16th-20th, 2006

L. Oberauer, TU Munich

Energy Spectra of AstrophysicalNeutrinos

thermal sources

Non-thermal sources

L ≈ 20 km

L ≈ 13000 km

atmosphericneutrinos:Ev ~ GeV

Pion production and subsequent decays (incl. muon)

π −> μ + νμ

μ −> e + νμ + νe

⎟⎟⎠

⎞⎜⎜⎝

⎛ Δ=→

νμ θνν

ELmP atm

atmx

222 27.1sin2sin)(

Oscillations and Atmospheric Neutrinos

Atmospheric Neutrinos and SuperKamiokande

Charged current reactions

νμ + N −> μ + N` and

νe + N −> e + N`

50 kt WaterCherenkovDetector

νμνe

Electron events Muon events

Up going Up going Neutrinos

μ

e

No-oscillation

Oscillation

Result atmospheric Neutrino-Oscillations

Best fit:Δm2

atm = 2.5×10-3 eV2

sin22θatm = 1.0

Best fit:Δm2

atm = 2.5×10-3 eV2

sin22θatm = 1.0

Confirmed by

•MACRO (Gran Sasso)

•Soudan (USA)

•K2K acceleratorlong baseline(250 km) experiment

•MINOS (USA) acc. exp. in 2006

Oscillations and Solar Neutrinos

Neutrino Energy in MeV

MeV7.2622He4 4 +++→ +eep ν

Sudbury Neutrino ObservatorySNOcharged current interaction (cc)

νe + D −> p + p + eneutral current interaction (nc)

νx + D −> νx + p + nelastic Neutrino-Electron scattering (cc

+ nc)

νx + e −> νx + e 1kt Cherenkov Detectorwith heavy water

SNO Result

• Flavour transitiondiscovered: 7 sigma !

• Reasonableagreement with solar model

Neutrinos from the Sun (νe) transform into νμ or ντ !

Solar Neutrino Oscillation

• Determination of Θ12 ~ 340

νe νμ,τ

Δm2 ~ 8 x 10-5 eV2

• Confirmation by reactorexperiment KamLAND

The solar matter effect – evidence by GALLEX/GNO

GALLEX/GNO

SNO

• Evidence for matter effect inside the Sun

• m2 > m1

• Why are neutrino masses so small?

• GUT

• Leptogenesis

Survival probability electronneutrino

pp- 7Be

8B

Future of Solar Neutrino Spectroscopy: low energies

• Monoenergetic 7Be • CNO, pepWhy?• Accurate Measurement of thermo nuclear

fusion processes:7Be ~ 10% => pp ~ 1% !

• CNO important for star development

The MSW Effect and newPhysics ?

Friedland, Lunardini, Peña-Garay, hep-ph/0402266

The MSW effect as filter

• Θ13

•sterile Neutrinos?

• magnetic Neutrino moment?

• new interactions ?

16L. Oberauer, TU München

Borexino @ Gran Sasso• 7Be solar neutrino measurement

• neutrino electron scattering

• CNO and pep neutrinos

• Long baseline reactor neutrinos

• Terrestrial neutrinos

• Supernova neutrinos

• Search for neutrino magnetic moment

Water filling started in August 2006

BOREXINO sees neutrinos from CERN (August 2006) !

First neutrino events in BOREXINO

Time of flight (CERN to LNGS) ~ 2.4 ms equivalent to ~ 730 km distance

Future Neutrino ObservatoriesUnsegmented50 kt liquid scintillatorLENA

HyperKamiokande (1 MtWater Cherenkov)

…Liquid Argon ~100 ktTPC

LAGUNA

• Large Aparatus for Grand Unification and Neutrino Astronomy

• European initiative (France, Germany, Italy, Switzerland, UK, Poland, Finland)

• Aim: Design studies for all 3 kinds of detectors (water Ch, scintillator, liquid argon) until ~ 2010

Physics goals of future Neutrino Observatories

• Gravitational collapse• Star formation rate in the early universe• Thermonuclear fusion reactions• Baryon number violation (Proton decay)• Leptonic CP – violation• Geophysics• Indirect search for Dark Matter• Active Galactic Nuclei – UHE Neutrinos

One example for LENA: Detection of the Diffuse Supernova Neutrino Background

(DSNB) ?

• up to now only limits

• flux and spectral shape depend on

Star formation rate

Gravitational collapse model

Extremely Large Observatories

Km3 Cherenkov detector in the mediterranian sea

Km3 Cherenkovdetector at the South Pole (Ice Cube)

Amanda

Frejus

Eν ∝ E-3.8

A change in the slope would indicate a non-atmospheric component

Atmospheric neutrino Waxmann-Bahcall limit: Model-independent upper bound

= 2π = 00-03 combined

Limits from Amanda

Ice-Cube ~ 3 10-9

Conclusions

• Neutrino physics very successfull in the last decade

• Neutrino masses and mixing established

• Physics beyond the standard model

• New window to astrophysical observations