Lecture 16 Relic Neutrinos

6 downloads 182 Views 822KB Size Report
AS 4022 Cosmology. Below Threshold: k T
Lecture 16 Relic Neutrinos

AS 4022

Cosmology

Below Threshold: k T neutrino mass: each type ( e µ τ ) is a mix of 3 mass states ( m1 m2 m3 ) travel time depends on mass interference,oscillation between types Solar neutrino problem solved: 2/3 of solar neutrinos change type enroute to Earth. Neutrinos from cosmic ray showers change type enroute thru the Earth. Oscillation wavelength depends on energy difference: 2 2 1/ 2   m 2c 2  mc m 2c 3 2 2 2 4 1/ 2 E = ( p c + m c ) = pc 1+ 2  ≈ pc 1+ = pc + 2  p  2p  2p   2 1

2

E1 − E 2 ∝ m − m2 ≡ Δ ( m12 )

2

2

Experimental limits:

Δ ( m12 ) = 8.0 ×10−5 eV 2 2

Δ ( m23 ) = 2.5 ×10−3 eV 2

€ AS 4022

Cosmology