Neutrino Physics

1
Neutrino Physics

• Krishna Kumar Neutrinoless Double Beta Decay
• The EXO experiment
• Laura Cadonati Solar Neutrinos
• The Borexino Experiment

2
The Neutrino Revolution
60Ni
Neutrinos interact very weakly with matter
Weak decay of 60Co Nucleus
60Co
Photons are the most abundant particles in the
universe. Neutrinos are the next most abundant.
Neutrinos are massive!
Neutrino flavors mix!

• What is the spectrum of neutrinos emitted by
  proton fusion in the sun?
• What is the flavor content of each neutrino?
• What is the absolute neutrino mass scale?
• Are neutrinos their own antiparticles?

What is the origin of mass for fundamental
particles?
3
Double Beta Decay
eL-
eL-
W-
2n
nR
eL-
W-
2n
nR
eL-
nL
W-
W-
nR
2-neutrino mode
2p
2p
Neutrinoless mode
EXO Experiment
Ionization
e-
e-
e-
e-
e-
e-
Liquid Xenon
e-
Currently under construction in a salt mine in
Carlsbad, NM
e-
e-
e-
Observation would imply that neutrinos are their
own anti-particles paradigm-shifting
discovery
e-
e-
e-
Avalanche photodiodes
Ground
-75kV
Must have half-life sensitivity of 1025 years!
4
Solar ? - Borexino
Gran Sasso (LNGS) 3500 m.w.e. shielding muon
flux 1/h/m2
Data ready for analysis now, in collaboration
with Princeton U. and Virginia Tech