2 Neutrino Oscillations
Already talked about two different oscillations:Solar Atmospheric Flavor states are superposition of mass eigenstates (Greek subscript is flavor and Roman subscript is mass state):
where
2 Neutrino Results
With m2sol ~ 5 x 10-5 eV2 & m2
atm ~ 3 x 10-3 eV2
But when plotting tan2 and not sin22, we know m1<m2<m3
3 Neutrino Oscillation
Reality is that there are 3 neutrino flavors (or possibly 4 or more) and 3 neutrino mass eigenstatesThis means neutrinos can oscillate between all three flavors
How many parameters?
3 Neutrino Mixing Matrix
Using 3 ranges from solar, atmospheric and reactor data:
LMA
Solar{Atm{ React
or
13
Why is 13 important? It is easily singled out in Ue3 matrix element and is directly linked to CP violating phase element
How do we measure 13? Use e experiment
(To leading order)
If the experiment is performed at the peak of this probability:
Using CHOOZ limit, maximum appearance probability is 5%
2 neutrino case:
Reality is slightly more complex
The neutrinos must pass through matter, it’s not a vacuum oscillationWe need to include CP violating phase effects
Off-Axis Experiments and Superbeams
Two proposed experiments to be off-axis experiments using “superbeams”NuMI JHF-SKBasically the idea is to create + by p+p collision, focus these + and get from +->+ +
Why Off-Axis?We see that as theta increases, there is a maximum for the neutrino energy with a wide range of pion energies contributing to it.
If we desire an enhancement at a particular neutrino energy, we look close to the max as given on the previous page.