Relation of Reactor 13 to Long-baseline Superbeam

Experiments

R. D. McKeownCaltech

Outline

• Overview• Reactor disappearance• Superbeam experiments• New comparison plots• Conclusions and Observations

Maki – Nakagawa – Sakata Matrix

Future Studies!

CP violation

Goals for the future

• Establish 13 non-zero

• Measure CP violation

• Determine mass hierarchy

(2003)

Distance (m)

P(ee)

Pee 1 cos4 13 1 sin212 sin2 m122L

4E

Dominant 12 Oscillation

Pee 1 sin2 213 sin2 m312L

4E

m21

2L

4E

cos4 13 sin2 212

Subdominant 13 Oscillation

e Disappearance

Reactor Experiment Sensitivity(Huber et al.,)

Three Classes of Proposals

1. sin2213 ~ 0.03 (e.g., CHOOZ II)

2. sin2213 ~ 0.01 (US approach?)

3. sin2213 << 0.01 (??)

Reactor Experiment Sensitivity

1

23

e Appearance

CP violation

matter

T2K- From Tokai To Kamioka

Mass hierarchy (+/-)

“Minakata” Plots

m2=3x10-3 eV2

Huber et al., comparison

Superbeam “Proposals”• T2K (JPARC-SK, 2009 start)

E=0.7 GeV, L=295km, L/E=421• NUMI (FNAL-Soudan)

E=1.5 GeV, L=732km, L/E=488• BNL-NUSL

E=2.0 GeV, L=2540km, L/E= 1270m2=2x10-3 eV2 L/E=394)

Run scenario: 5yr – then

+/- 0.03

cp

T2K

— normal— inverted

m2=2x10-3 eV2

5 years

+/- 0.01reactor

m2=2x10-3 eV2

+/- 0.05

NUMI (FNAL-Soudan)

m2=2x10-3 eV2

5 years

NUMI (FNAL-Soudan)

+/- 0.01reactor

m2=2x10-3 eV2

m2=3x10-3 eV2

m2=2x10-3 eV2

BNL-NUSL

CONCLUSIONS

• Reactor measurement with sin2213 ~ 0.01can provide significant new constraintswhen combined with 5yr superbeam result – perhaps even decide hierarchy

• L/E for superbeam expt seems critical

• Coordination appears beneficial