Spectral measurement of the electron antineutrino oscillation amplitude and frequency using 500 live days of RENO data

Abstract

The Reactor Experiment for Neutrino Oscillation (RENO) has been taking electron antineutrino (ν e ) data from the reactors in Yonggwang, Korea, using two identical detectors since August 2011. Using roughly 500 live days of data through January 2013 we observe 290 775 (31 514) reactorν e candidate events with 2.8% (4.9%) background in the near (far) detector. The observed visible positron spectra from the reactorν e events in both detectors show a discrepancy around 5 MeV with regard to the prediction from the current reactorν e model. Based on a far-to-near ratio measurement using the spectral and rate information, we have obtained sin 2 2θ 13 ¼ 0.082 AE 0.009ðstat:Þ AE 0.006ðsyst:Þ and jΔm

Observation of reactor antineutrino disappearance using delayed neutron capture on hydrogen at RENO

“…The energy calibration for the target region is accomplished using several radioactive sources and the IBD n-H and n-Gd events and well described in Ref. [9,10]. The energy calibration for the GC region is made using radioactive sources of 54 Mn, 68 Ge, 65 Zn, 60 Co, 241 Am-Be and 252 Cf-Ni, and n-H from IBD signals.…”

Estimation of reactor neutrino fluxes

“…The predicted rate is 6% higher than that observed, a feature that is commonly referred to as the reactor antineutrino anomaly and has been considered possible evidence for sterile neutrinos [4]. More recently, precise measurements of ν e energy spectra have also shown a ∼10% excess relative to prediction in the region of 5 to 7 MeV [5,6,7]. In these proceedings I will examine the details behind these discrepancies, and discuss the substantial recent developments in this field.…”

“…Subsequent detection of the neutrons produced by IBD allows for effective background rejection. The most recent generation of direct measurements have observed more than 1 million ν e interactions, and obtained percent-level uncertainties in both the rate and energy spectra [5,6,7]. This precision has been putting pressure on the field to obtain more accurate predictions of the reactor ν e flux.…”

Neutrino Oscillation Analysis of 217 Live Days of Daya Bay and 500 Live Days of RENO

“…For Daya Bay we consider the 217 days of data, taken between December of 2011 and July of 2012 in the configuration with only 6 antineutrino detectors [24]. In the case of RENO, we consider the data from 500 live days, taken between August 2011 and January 2013 [25] with both, the near and far detectors. These data sets have been chosen for the convenience and relative simplicity in reproducing their results from publicly available resources.…”