seminar @ cunpa 2013.10.18
TRANSCRIPT
Yoshitaro TakaesuKIAS/KNRC
The Sensitivity to Mass Hierarchy determination of Future Reactor
Neutrino experiments
In collaboration with S.F. Ge, N. Okamura and K. HagiwaraJHEP 1305:131,2013
Analysis methodWe define
Naively, the significance of this rejection is , but…
NHIH
Not appropreate for the MH determination
c.f.) Qian et.al. arXiv: 1210.3651
Evslin et.al. arXiv: 1305.5150
NH is true: tends to be Positive.
IH is true: tends to be Negative.
IH is rejectedNH is rejected
NH is true case
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Sensitivity to the Mass hierarchy
The typical sensitivity curve of this experiment
Small flux
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Vvvv vvv
Effect of Energy Resolution 2
18kton 16.5GW 5yrs
a = 3%a = 2%
b = 0 b = 1% Sensitivity 40%
Imrovement of b term is also important17
Current value
How to achieve better Energy Resolution?
Increase the photo-electron (p.e.)detected by PMT.
p.e.~ 200 pe/MeV ~ 2000 pe/MeV
Ex)
• Increase PMT coverage
• Increase QE of PMT
• More transparent LS
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~ 6% ~ 2%
E. Ciuffoli, J. Evslin, X. Zhang: 1302.0624Y-F. Li, J. Cao, Y. Wang, L. Zhan: 1303.6733
ΔL = L1 – L2
Reactor1
Multi-reactor interference
L1 L2
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Reactor1 + Reactor2
multi-cores
Multi-reactor interference 16.5GW
18kton 5yrs
a = 3%, b = 0.5%
All Reactors50 km
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250m
Parameter measurement
< 0.5% accuracy
can be measured accurately @ L ~ 50 km
L = 50km
1%
1%
1%
1%
* Effect of energy scale unc. Is not considered.
SummaryFuture Reactor neutrino Experiment for MH determination
For > 3-sigma determination within 5 years
a < 3%
b < 0.5%
of Energy Resolution is required
with 16.5GW 18kton Reactor Complex.
Interference among reactor cores significantly affects the sensitivity.
•Energy Scale uncertainty should be controlled very carefully.arXiv: 0901.2976, 1208.1551, 1308.0591
* Neutrino parameters can be determined with < 1% accuracy.
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