Reactor Neutrino Measurement of 13

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Reactor Neutrino Measurement of ?13
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?13 and CP Violation
Neutrino Mixing Matrix
solar ? present
0??? experiments future
atmospheric ? present
reactor and accelerator ? future
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Reactor Neutrino Measurement of ?13
Searching for Subdominant Oscillations in ?e ?
??,? to measure the last yet undetermined
neutrino mixing angle, ?13
?13 oscillation signature
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Sensitivity and Complementarity of ?13 Experiments
Reactor ?13 experiment No matter
effect Correlations are small, no
degeneracies Independent of solar osc. parameters
?12,?m212
Sensitivity to sin22?13
Ref Huber et al., hep-ph/0303232
10-3
10-1
10-2
?13 sensitivity of reactor experiments comparable
to JHF-SK
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A ?13 Reactor Experiment in the US ?

• Site Requirements
• 1. A reactor, or multiple-reactor complex
• 2. Sites for 2-3 detectors at distances of 1-5 km
  from reactor
• 3. Detector overburden for reduction of cosmic
  ray background
• Man-made overburden or
• Underground site in a mine (good overburden)
• Underground site in tunnels (movable
  detectors)

Movable detectors?
Does a site like this exist?
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Diablo Canyon - An Ideal Site?
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Diablo Canyon Site
1500 ft
600 ft
Powerful Two reactors (3.13.1 GW Eth) on the
California coast Overburden Horizontal tunnel
could give 800 mwe shielding! Infrastructure
Roads built for heavy machinery. Controlled
access. Scientific Collaborations existing
collaborations between PGE and marine
scientists, biologists, and geologists with site
access.
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An Ideal Oscillation Experiment with Variable
Baseline? Possible layout of 2 or 3 detectors
at Diablo Canyon
FAR II distance 2-2.5 km
FAR I distance 1.5-2 km
tunnels
NEAR distance 0.5 km
600-800 mwe
400 mwe
Tunnel excavation required ? further studies
necessary
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Schematic of Movable Detector
Modular, movable liquid scintillator detector
to control systematics active muon veto
Vfiducial 80-100 t
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Summary Reactor Measurement of ?13
Measurement of fundamental neutrino mixing
angle with discovery opportunity and long-term
impact. Reactor experiment gives clean
measurement of sin22?13. Sensitivity of
sin22?13 lt 0.005 comparable to next-generation
accelerator experiments. A timely ?13
measurement will define the future of accelerator
? physics. Reactor results will be on a
timescale that complements off-axis results
Further design studies and site evaluation
necessary.
http//theta13.lbl.gov/
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