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 ~5×10 21 /sec  Cost-free, intense, low-energy & well-known neutrino source ! Reactor Neutrinos

Reactor Antineutrino Oscillation 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 (Double Chooz ) sin 2 (2  13 ) = 0.086±0.051  March 2012 (Daya Bay) sin 2 (2  13 ) = 0.092±0.017  April 2012 (RENO) sin 2 (2  13 ) = 0.113±0.023  June 2012 (Double Chooz) sin 2 (2  13 ) = 0.109±0.039  Oct (Daya Bay) sin 2 (2  13 ) = 0.089±0.011  March 2013 (RENO) sin 2 (2  13 ) = 0.100±0.018  Double-CHOOZ, arXiv: , (2012) (5.2  ) (4.9  ) Daya Bay Oct RENO Mar. 2013

- 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 (402 days) (18 % precision) (5 years) (8 % precision) statistical error : ±0.010 → ±0.006 systematic error : ±0.015 → ±0.005 (5 years) (4 % precision) (12.5 % precision) (138 days) (35.8 % precision) (5 years) (10 % precision) Near detector (spring of 2014)

Expected Results from Current Reactor Experiments  sin 2 (2  13 ) to 4~5% accuracy within 3 years : → determination of CP phase with accelerator results   m 2 31 directly from reactor neutrinos : ← spectral disappearance of reactor antineutrinos  precision reactor antineutrino spectra : → study reactor anomaly or sterile neutrinos

Reactor Anomaly ? (3  vs. 4 ) 3 adapted from Lasserre AAP m100 m1 km10 km100 km Average = ±0.024 Reactor  13 near detector ( 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%) ( %) (±13.3%) ∆m 21 2 / |∆m 31(32) 2 | ≈ 0.03 sin 2  12 = 0.312±0.017 (±5.4%) sin 2  23 = −0.03 ( %) sin 2  13 = ± (±13.5%)  Precise measurement of  12 and  m 2 21 at ~50 km in a year (← 5.4%) in 2~3 years (← 2.6%)

1 st  m 2 21 Maximum (L~50km) ; precise value of  12 &  m mass hierarchy (  m 2 31 ) 1 st  m 2 21 Maximum (L~50km) ; precise value of  12 &  m mass hierarchy (  m 2 31 ) Precise  12 Mass Hierarchy Large Deficit Ripple

Far Detector Near Detector RENO kton LS Detector ~47 km from YG reactors Mt. Guemseong (450 m) ~900 m.w.e. overburden

17 Daya Bay II Site Candidate

Lufeng NPP planned 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,  m 2 21, &  m 2 31, 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.