Recent Results from RENO Experiment

KAIST Jonghee Yoo

on behalf of the RENO Collaboration 2020-06-25 Neutrino 2020, Chicago, USA

2Yoo-2020-06-25 @ Neutrino 2020 for RENO Collaboration

RENO Collaboration

9 Institutions and 40 Physicists Chonnam National University Dongshin University Gwangju Institute of Science and Technology Gyeongsang National University Korea Advanced Institute of Science and Technology Kyungpook National University Seoul National University Seoyeong University Sungkyunkwan University

Reactor Experiment for Neutrino Oscilla5on

● Start of project: 2006

● The first reactor experiment running with both near and far detectors since August 2011

Yonggwang

South Korea

3Yoo-2020-06-25 @ Neutrino 2020 for RENO Collaboration

RENO Experimental Setup

Near Detector (120 m.w.e)

Far Detector (450 m.w.e)

1383 m

294 m

Hanbit Nuclear Power Plant Complex 6 Reactor array

2.8GWth/reactor

4

RENO Detectors

● Target (Gd-loaded LS) 16 tons● Gamma catcher (LS) 29 tons ● Buffer (Mineral oil) 64 tons ● Veto (Water) 353 tons

Two idenAcal (near and far) detectors

Detector Calibration

354 (Buffer) + 67 (Veto) 10” PMTs

Yoo-2020-06-25 @ Neutrino 2020 for RENO Collaboration

0 2 4 6 8 100

0.05

0.1

0.15

0.2

0.25

0.3

Energy [MeV]

Prob

abili

ty

an5neutrinosprompt

5

RENO Antineutrino Detection Principle

Yoo-2020-06-25 @ Neutrino 2020 for RENO Collaboration

Ethr⌫ =

(mn +mp)2 �m2p

2mp= 1.806MeV

Eprompt = K.E.(e+) + 1.022MeV ' E⌫ � 0.78MeV

Eprompt = K.E.(e+) + 2⇥ (0.511)MeV

p n

Inverse Beta Decay

e+e� ! 2�

n-Gd ! �...

(prompt)

(delayed ~30µs)

6Yoo-2020-06-25 @ Neutrino 2020 for RENO Collaboration

Recent Results from RENO

● “Fuel-composition dependent reactor antineutrino yield at  RENO” Phys. Rev. Lett. 122, 232501 (2019)

● “Observation of Reactor Antineutrino Disappearance Using Delayed Neutron Capture on Hydrogen at RENO” JHEP04 (2020) 029 - Update of 1500 days data

- The first θ13 measurement in n-H channel ➔ see poster session #56 by Dr. Eunhyang Kwon

● “Search for Sub-eV Sterile Neutrino at RENO” arXiv:2006.07782 (2020) posted at online 14 June 2020 ➔ see poster session #128 by Dr. Jiwoong Seo

● Updated analysis of 2900 days (Aug. 2011 – Feb. 2020) of RENO data - 2200 Days results published at PRL121 (2018) 20, 201801 - Update on Reactor Antineutrino Anomaly (RAA) - Update on θ13 and Δm2 from n-Gd channel - Update on 5 MeV excess (finer bin measurement) ➔ see poster session #62 by Dr. DongHa Lee

7Yoo-2020-06-25 @ Neutrino 2020 for RENO Collaboration

Measured Spectra of IBD Prompt Signal

RENO 2900 days (2200 + 700 days) : Aug. 2011 — Feb. 2020 - Clear excess at 5MeV compared to the Huber-Mueller prediction

Near detector live time: 2509 days#IBD candidates: 989,736Background rate: 2.26 ± 0.05 %5 MeV excess rate: 2.50 ± 0.06 %

Far detector live time: 2908 days# IBD candidates: 120,383Background rate: 4.77 ± 0.19 %5 MeV excess rate: 2.26 ± 0.18 %

0.9387 ± 0.0017

Near

Near

Far

Far

0.9368 ± 0.0050

8Yoo-2020-06-25 @ Neutrino 2020 for RENO Collaboration

Observed IBD Rate VS Thermal Power

Near

Near

2.722 ± 0.082 % 2.416 ± 0.223 %

Far

Far

9Yoo-2020-06-25 @ Neutrino 2020 for RENO Collaboration

5 MeV Excess VS Thermal Power

10Yoo-2020-06-25 @ Neutrino 2020 for RENO Collaboration

Fuel Dependence of the Fractional 5 MeV Excess (2900 Days)

2.5124 ± 0.0609

��2 = 10.33 (3.21�)

Preliminary

11Yoo-2020-06-25 @ Neutrino 2020 for RENO Collaboration

Absolute Reactor Neutrino Flux

Reactor Antineutrino Anomaly (RAA)

R = 0.940± 0.001(stat.)± 0.020(sys.) for H-M model

yf = 5.8303± 0.1249(⇥10�43 cm2/fission)IBD yield:R = 0.983± 0.001(stat.)± 0.021(sys.)Data / Prediction: for ILL+Vogel modelF 235 : F 238 : F 239 : F 241 = 0.571 : 0.073 : 0.300 : 0.056Average fission fraction:

Preliminary

12Yoo-2020-06-25 @ Neutrino 2020 for RENO Collaboration

Far to Near Prompt Spectra Shape Comparison

RENO 2900 days (Aug. 2011 — Feb. 2019) - Energy dependent disappearance of reactor antineutrinos

Preliminary

13Yoo-2020-06-25 @ Neutrino 2020 for RENO Collaboration

Neutrino Oscillation: θ13 and Δm2ee

RENO 2900 days (Aug. 2011 — Feb. 2020)

± 7.0%

± 4.4%

sin2 2✓13 = 0.0892± 0.0044(stat.)± 0.0045(sys.)

|�m2ee| = 2.74± 0.10(stat.)± 0.06(sys.)(⇥10�3eV2)

Preliminary

14Yoo-2020-06-25 @ Neutrino 2020 for RENO Collaboration

Neutrino Oscillation: θ13 and Δm232

15Yoo-2020-06-25 @ Neutrino 2020 for RENO Collaboration

Neutrino Oscillation: L/E Dependence

P (⌫e ! ⌫e) ' 1� sin2 2✓13 sin2

✓1.27�m2

eeL

E⌫

◆

sin2 2✓13 = 0.0892± 0.0044(stat.)± 0.0045(sys.)

|�m2ee| = 2.74± 0.10(stat.)± 0.06(sys.)(⇥10�3eV2)

Preliminary

16Yoo-2020-06-25 @ Neutrino 2020 for RENO Collaboration

RENO 1500-Days Data n-H Analysis Results

17Yoo-2020-06-25 @ Neutrino 2020 for RENO Collaboration

Neutrino Oscillation from n-H Data

Independent measurement of sin22θ13 using 1500 live days n-H data

n-H Data

sin2 2✓13 = 0.086± 0.008(stat.)± 0.014(sys.)�using PDG input: |�m2

ee| = 2.562⇥ 10�3 eV2�

18Yoo-2020-06-25 @ Neutrino 2020 for RENO Collaboration

RENO Sterile Neutrino Search

(3+1) Neutrino ModelP (⌫e ! ⌫e) ' 1� sin2 2✓13 sin

2

✓1.27�m2

31L

E⌫

◆� sin2 2✓14 sin

2

✓1.27�m2

41L

E⌫

◆

19Yoo-2020-06-25 @ Neutrino 2020 for RENO Collaboration

RENO Sterile Neutrino Search

arXiv: 2006.07782 (posted on 14th June 2020)

2200 Days of RENO Data

Prompt Energy (MeV)1 2 3 4 5 6 7 8

Mea

sure

d / E

xpec

ted

from

Nea

r

0.8

0.9

1

1.1

1.2 2 eV-210× = 5412mΔ 2 eV-310× = 541

2mΔ2 eV-310× = 141

2mΔ = 0.1 assumed14θ22sin

Data predictionνUncertainty of 3

3−10 2−10 1−10 114θ22sin

4−10

3−10

2−10

1−10

1

)2 (e

V⏐

412m

Δ ⏐

RENO 95% C.L.

)σ1±RENO 95% C.L. expectation (

20Yoo-2020-06-25 @ Neutrino 2020 for RENO Collaboration

RENO Sterile Neutrino Search

RENO 2200 days

arXiv: 2006.07782 (posted on 14th June 2020)

3−10 2−10 1−10 114θ22sin

4−10

3−10

2−10

1−10

1

)2 (e

V⏐

412m

Δ ⏐RENO 95% C.L.Daya Bay 90% C.L.Bugey 90% C.L. (40m/15m)KARMEN+LSND 95% C.L.NEOS 90% C.L.

(2020)

21Yoo-2020-06-25 @ Neutrino 2020 for RENO Collaboration

Summary

● Report updated results using RENO 2900 days data

● Precision measurement of θ13 and |Δmee2|

● Absolute reactor neutrino flux : R = 94.0±2.0 % (for HM)

● Correlation between 5 MeV excess and 235U fission (3.2σ C.L.)

● The first RENO sterile neutrino search results: arXiv:2006.07782

(1) DongHa Lee, “Updated results on reactor antineutrino oscillation amplitude and frequency for 2900 days at RENO” (poster #62)

(2) Jiwoong Seo, “Search for Sterile Neutrinos at RENO” (poster #128)(3) Eunhyang Kwan, “θ13 measurement using data with neutron capture

on hydrogen at RENO” (poster #56)

RENO Poster Presentations in Neutrino 2020

Backup Slides

23Yoo-2020-06-25 @ Neutrino 2020 for RENO Collaboration

RENO 2900-Days Daily IBD Rate

700 days2200 days

Near

Far

Preliminary

Preliminary

24Yoo-2020-06-25 @ Neutrino 2020 for RENO Collaboration

RENO Fuel Fraction in the Reactor Core

Preliminary

25Yoo-2020-06-25 @ Neutrino 2020 for RENO Collaboration

Fuel Dependence of IBD Yield

yf = 5.8303± 0.0063⇥ 10�43 cm2/fissionIdentical yieldNull fuel dependence ruled out by 7.7σ

Preliminary

26Yoo-2020-06-25 @ Neutrino 2020 for RENO Collaboration

RENO 2900-Day Data Analysis Update

2.886σ

0.975σ

y239=

4.142+0.250

�0.245 ⇥

10�43cm

2/fission

y235 = 6.155+0.183�0.178 ⇥ 10�43 cm2/fission

Preliminary

27Yoo-2020-06-25 @ Neutrino 2020 for RENO Collaboration

RENO 1500-Days Data n-H Analysis Results

28Yoo-2020-06-25 @ Neutrino 2020 for RENO Collaboration

RENO 1500-Days Data n-H Analysis Results

Independent measurement of sin22θ13 using 1500 live days n-H data

sin2 2✓13 = 0.086± 0.008(stat.)± 0.014(sys.)

|�m2ee| = 2.562⇥ 10�3 eV2

29Yoo-2020-06-25 @ Neutrino 2020 for RENO Collaboration

RENO Sterile Neutrino Search (Additional Plots)

RENO sterile neutrino searchRate only (2200 days)

(2020)

This results

RENO sterile neutrino searchSpectrum (2200 days)