three neutrino oscillation lecture two - physics | cwru · three neutrino oscillation lecture two...
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reνolution
Three Neutrino OscillationLecture Two
Lindley WinslowMassachusetts Institute of Technology
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The neutrino is neutral.
The neutrino only interacts weakly.
The neutrino has a small non-zero mass.
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!e!
!2"
!µ"
!1!
#"
#"
Two neutrino mixing determined by one mixing angle and and one mass difference squared.
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Three neutrino mixing will be defined by three mixing angles and two independent mass differences.
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Do not look at the blue line....
The best fit comes from Chooz, sin22θ13 < 0.16, and putting together everything sin22θ13 ~ 0.06.
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u c! t!d s! b!
CC
We have seen this before...
u c! t!d s! b
is actually
This is the famous CKM Matrix that describes the
quark mixing.
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One rule we hold dear.... CPT Conservation
or
CPT conservation is all mixed together with the Lorentz invariance, locality and causality of your theory, so we do not like to mess with it.
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Disappearance Experiments.... CPT and CP are the same condition.
So you can never detect plain CP violation in a disappearance experiment.
or
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Appearance Probability in Vacuum:
And there are terms for the CP violating phase which is really what we want to go after.....
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Posc(!"# !$)!
P osc(! "#
!$)!
CP
%&
CP parameter!
0
'&
Visualizing the effect of the CP phase.....
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You want the biggest effect possible.....
Maximize This!
atmospheric Δm2 is ~0.001 eV2
standard beam energy is 1GeV
Your beam needs to go 1,000km!
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Remember that MSW effect for neutrinos going through matter.
Posc(!"# !$)!
P osc(! "#
!$)!
CP
CP + matter,
%&
CP parameter!
0
'&
Matter will effect only neutrinos so this is a type of CP violation but not the effect we want to measure!
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Posc(!"# !$)!
P osc(! "#
!$)!
CP
CP + matter, %&m2 <0
CP + matter, &m2 >0
'%
So in order to interpret data you will need to model the matter between FermiLab and South Dakota.
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Liquid Argon is super cool....
Proposals for multi-kton LAr detectors are in the running,but I will focus on the water Cerenkov Detector.
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Ten years of running LBNE,If the hierarchy is normal and there are no upgrades to the FermiLab beam.
A lot of different jelly beans to choose from....
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What we want is a decay at rest beam (DAR)....
P DumpPions! neutrinos No νe!
These are harder to make and the μ- capture.
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free !protons!
20km! 8km! 1.5km!
osc max (!/2)!at 40 MeV!
off max (!/4) !at 40 MeV!
A multiple-baseline,!single-detector!experiment!
Constrains!flux!
And here is the idea....
Re-use your gigantic detector!
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And with the multiple baselines.....
You can use the interference between the terms to pull out the magnitude of the CP effect.
p
!̄ep
Gd
n
e+
Anti-Neutrino Detection - Inverse Beta Decay
Event #1 Ee = Eν - 0.8MeV
Event #2 Eγ~8MeV
30μs
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And you saw this trick before......
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Two backgrounds, “invisible” muons from atmospheric neutrinos.....
and the diffuse supernova background.
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Daedalus Phase 1 + 2 LBNE 5 yrs nu + 5 yrs nubar
By Construction our performance is similar to LBNE,
but the systematic uncertainties are completely different!
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Working together is always better.....
With Different interactions, Different beams, Different energies, We beat down the systematic uncertainties and We win!
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(! )!(! )! vs.
vs.
They have decided to have tiny masses.
They have decided to have large mixing.
Why not an inverse hierarchy and large CP violation?