New Results from RENO and The 5 MeV Excess

TL;DR

The RENO experiment measured neutrino oscillation parameters with high precision and observed a notable 5 MeV excess in the reactor neutrino spectrum correlated with reactor power.

Contribution

This paper presents the first precise measurement of  mixing angle and reports the 5 MeV excess in reactor neutrino data, highlighting new spectral features.

Findings

Measured  mixing angle: sin^22 = 0.101 b1 0.008 (stat.) b1 0.010 (syst.)

Detected a 5 MeV excess in the neutrino spectrum

Observed correlation between the excess and reactor thermal power

Abstract

One of the main goals of RENO (Reactor Experiment for Neutrino Oscillation) is to measure the smallest neutrino mixing angle {\theta}13 using reactor neutrinos in Korea. RENO is the first reactor experiment taking data with two identical detectors in different locations (Near and Far), which is critical to reduce systematic uncertainty in reactor neutrino flux. Our data taking has been almost continuous since Aug. 2011 and we have collected about 434,000 (54,000) electron anti-neutrinos in the Near (Far) detector by 2013. Using this data (about 800 live days) we present a new result on {\theta}13: sin22{\theta}13 = 0.101 +/- 0.008 (stat.) +/- 0.010 (syst.). We also report the 5 MeV excess present in the prompt signal spectrum in our data, and its correlation with our reactor thermal power.