Future Reactor Neutrino Physics

Soo-Bong Kim (KNRC, Seoul National University)“International Workshop on RENO-50, June 13-14, 2013”

Nuclear Power Plants

Yonggwang

Reactor Neutrinos

~5×1021 n/sec

Cost-free, intense, low-energy & well-known neutrino source !

Reactor Neutrinos

Reactor Antineutrino Oscillation

P ne ne 1 cos413 sin2 212 sin2 1.27m12

2 LEn

sin2 213 sin2 1.27m13

2 LEn

Daya Bay

RENO

Double Chooz

Reactor 13 Experiments

RENO at Yonggwang, Korea

Daya Bay at Daya Bay, China

Double Chooz at Chooz, France

A Brief History of 13 from Reactor Experiments

Nov. 2011 (Double Chooz ) sin2(213) = 0.086±0.051

March 2012 (Daya Bay) sin2(213) = 0.092±0.017

April 2012 (RENO) sin2(213) = 0.113±0.023

June 2012 (Double Chooz) sin2(213) = 0.109±0.039

Oct. 2012 (Daya Bay) sin2(213) = 0.089±0.011

March 2013 (RENO) sin2(213) = 0.100±0.018

Double-CHOOZ, arXiv:1207.6632, (2012)

(5.2 s)

(4.9 s)

Daya Bay Oct. 2012

RENO Mar. 2013

nn

E

LmE

LmPee 4sin2sincos

4sin2sin1

2212

122

134

2312

132

- Clean measurement of 13 with no matter effects

* Reactor

13 from Reactor and Accelerator Experiments

* Accelerator - mass hierarchy + CP violation + matter effects

Complementary :

Combining results from accelerator and reactor based experiments could offer the first glimpse of CP.

Precise measurement of 13

Future Precision Measurement of 13

018.0100.0 (402 days)(18 % precision)

008.0 (5 years)

(8 % precision)

statistical error : ±0.010 → ±0.006 systematic error : ±0.015 → ±0.005

004.0 (5 years)

(4 % precision)

011.0089.0 (12.5 % precision)

(138 days)

039.0109.0 (35.8 % precision)

010.0 (5 years)

(10 % precision)

Near detector (spring of 2014)

Expected Results from Current Reactor Experiments

sin2(213) to 4~5% accuracy within 3 years : → determination of CP phase with accelerator results

m231 directly from reactor neutrinos :

← spectral disappearance of reactor antineutrinos

precision reactor antineutrino spectra : → study reactor anomaly or sterile neutrinos

Reactor Anomaly ? (3n vs. 4n)

3n

adapted from Lasserre AAP 2012

4n

10 m 100 m

1 km 10 km

100 km

Average = 0.935 ±0.024

Reactor 13

near detector (0.3-0.4 km)

Reactor 13

far detector (1-2 km)

Reactor nuclear physics vs. new physics ?

~0.5M events at RENO (~0.1% stat. error)

NUCIFER SCRAAM Stereo POSEIDON Neutrino4 Hanaro-SBL DANSS Ricochet

2012 Particle Data Book

(±2.8%) (±2.7%)

(±3.1%)(+5.2-3.4%)

(±13.3%) ∆m21

2 / |∆m31(32)2| ≈ 0.03

sin212 = 0.312±0.017 (±5.4%)

sin223 = 0.42+0.08−0.03 (+19.0 -7.1%)

sin213 = 0.0251±0.0034 (±13.5%)

Precise measurement of 12 and m221 at ~50 km

s 1%0.1~

sinsin

122

122

in a year

(← 5.4%) s 1%0.1~

212

212

mm

in 2~3 years

(← 2.6%)

1st m221 Maximum (L~50km) ;

precise value of 12 & m221 + mass hierarchy (m2

31)

sin2 212

2131212

31 2sin2sin21sin2cos

Precise 12

Mass Hierarchy

Large Deficit

Ripple

2131212

31122

132

212

122

134

2sin2sin21sin2cossin2sin

sin2sincos1

nn eeRP

Far Detector

Near Detector

RENO-5010 kton LS Detector

~47 km from YG reactors Mt. Guemseong (450 m) ~900 m.w.e. overburden

17

Daya Bay II Site Candidate

Lufeng NPPplanned 6x2.9GW

Daya Bay II Site Candidate (other option)

Closing Remarks

A clear disappearance of reactor antineutrinos is observed. The smallest mixing angle of 13 is firmly (to 13~18% precision) measured by the reactor experiments.

Reactor neutrino experiments will make accurate measurements of reactor neutrino fluxes and spectra to search for sterile neutrinos.

Longer baseline (~50 km) reactor experiments is under pursuit to perform high-precision measurements of 12, m2

21, & m231 , and to

determine the mass hierarchy.

The mixing angle of 13 expects to be measured to ~5% precision within 3 years. This will provide the first glimpse of CP. if accelerator results are combined.