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

3 Nobel prizes 1988 LEDERMAN, SCHWARTZ and JACK STEINBERGER – detected muon neutrinos 1995 REINES – detected reactor neutrinos in 1956 2002 RAYMOND and KOSHIBA – detected solar neutrinos

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

Neutrino oscillations

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

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

In the nucleus Atom recoil

B-decay energy spectrum 8

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

Supernova 1987a 51kpc away 24 neutrinos

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.

Theoretical neutrino spectrum

Total neutrino background luminosity

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

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

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

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