Big World of Small NeutrinosBig World of Small Neutrinos

Roman ShcherbakovRoman Shcherbakov21, March, 200721, March, 2007

3 Nobel prizes3 Nobel prizes

1988 1988 LEDERMAN,LEDERMAN, SCHWARTZ and JACKSCHWARTZ and JACK STEINSTEINBERGBERGERER – – detected muon neutrinosdetected muon neutrinos

1995 REINES – detected reactor neutrinos in 19561995 REINES – detected reactor neutrinos in 1956 2002 2002 RAYMOND andRAYMOND and KOSHIBAKOSHIBA – detected solar neutrinos – detected solar neutrinos

Neutrino opticsNeutrino optics

NS

in the Neutron Star

in the Earth

in the Sun

Neutrino oscillationsNeutrino oscillations

Neutrino oscillationsNeutrino oscillations

Hierarchy is not yet known

Mixing matrix

=>different neutrino & antineutrino

For E=10MeV L12~300km L13~10km

Only 1/3 of born electron neutrino stay electron neutrino

Solar neutrinosSolar neutrinos> 50 trillion solar neutrinos pass through the human body every second

it would take approximately one light year of lead to block half of them

butbut

400kEv

10MEv

Qen e p:decayβAtomrecoil

In the nucleus

B-decay energy spectrumB-decay energy spectrum8

MSW effectMSW effect

Oscillations enforced by scattering

•Not important for the Sun

•Considered in detailed calculations of supernova explosions

Supernova 1987aSupernova 1987a

51kpc away

24 neutrinos

Supernova explosion (type II)Supernova explosion (type II)

Theoretical neutrino spectrumTheoretical neutrino spectrum

Total neutrinoTotal neutrinobackground luminositybackground luminosity

Cosmic neutrino background (CNB)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 cuspyCuspy halos are not cuspy

2 solutions

• Large annihilation cross-section of cold dark matter (KKT model)

• Warm dark matter

Cold dark matter annihilationCold dark matter annihilation

Doesn’twork

Only decay tosterile particlesIs possible

ConclusionsConclusions

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

☺☺☺☺☻☻☻☻