1. Big World of Small Neutrinos
Roman Shcherbakov
21, March, 2007

2. 3 Nobel prizes
1988 LEDERMAN, SCHWARTZ and JACK STEINBERGER – detected muon neutrinos
1995 REINES – detected reactor neutrinos in
2002 RAYMOND and KOSHIBA – detected solar neutrinos

3. Neutrino optics NS
in the Neutron Star
in the Sun
in the Earth

4. Neutrino oscillations

5. Neutrino oscillations
Mixing matrix
=>different neutrino & antineutrino
Hierarchy is not yet known
For E=10MeV
L12~300km
L13~10km
Only 1/3 of born electron neutrino stay electron neutrino

6. Solar neutrinos
> 50 trillion solar neutrinos pass through the human body every second
but
it would take approximately one light year of lead to block half of them
400kEv
10MEv

7. In the nucleus
Atom
recoil

8. B-decay energy spectrum8

9. MSW effect Oscillations enforced by scattering
Not important for the Sun
Considered in detailed calculations of supernova explosions

10. Supernova 1987a
51kpc away
24 neutrinos

11. Supernova explosion (type II)
Simplified core collapse scenario: (a) A massive, evolved star has onion-layered shells of elements undergoing fusion. An inert iron core is formed from the fusion of Silicon in the inner-most shell. (b) This iron core reaches Chandrasekhar-mass and starts to collapse, with the outer core (black arrows) moving at supersonic velocity ("shocked") while the denser inner core (white arrows) travel sub-sonically; (c) The inner core compresses into neutrons and the gravitational energy is converted into neutrinos. (d) The infalling material bounces off the nucleus and forms an outward-propagating shock wave (red). (e) The shock begins to stall as nuclear processes drain energy away, but it is re-invigorated by interaction with neutrinos. (f) The material outside the inner core is ejected, leaving behind only a degenerate remnant.

12. Theoretical neutrino spectrum

13. Total neutrino background luminosity

14. Cosmic neutrino background (CNB)
Similar to CMB
Undetectable by any means
Bad dark matter candidate –
relativistic in the time of recombination
Cold dark matter is favorable for structure formation

15. Cuspy halos are not cuspy
2 solutions
Large annihilation cross-section of
cold dark matter (KKT model)
Warm dark matter

16. Cold dark matter annihilation
Doesn’t
work
Only decay to
sterile particles
Is possible

17. ☻ ☺ Conclusions Neutrinos provide a new great tool for:
probing the interior of the Sun
observing the early stages of supernovae
proving particle theories ☺ ☻