Search

RENO (Reactor Experiment for Neutrino Oscillation) is the first reactor neutrino experiment which began data-taking in 2011 with two identical near and far detectors in Yonggwang, Korea. Using 1500 live days of data, sin^2(2{\theta}_13) and |{\Delta}m^2_ee| are updated using spectral measurements: sin^2(2{\theta}_13) = 0.086 +/- 0.006 (stat.) +/- 0.005 (syst.) and |{\Delta}m^2_ee| = 2.61+0.15-0.16 (stat.) +/- 0.09 (syst.) (x10^-3 eV^2). The correlation between the 5 MeV excess rate and the reactor thermal power is again clearly observed with the increased data set., Comment: 5 pages, 5 figures, Talk presented at TAUP 2017, Sudbury, ON, Canada, 24-28 July 2017

A brief overview of recent results from accelerator and reactor neutrino experiments and future prospects are presented. The experimental status of sterile neutrinos is also discussed.

This paper briefly describes recent progress of RENO and next generation future prospect of the reactor neutrino oscillation experiment, RENO-50. Recently the RENO experiment has updated its latest value on sin22θ 13 and provided new results on 5 MeV excess, Δm2 ee, θ 13 with n-H analysis, absolute antineutrino flux measurement, and sterile neutrino search. It gives rich programs of neutrino properties, detector development, nuclear monitoring and application. Using reactor neutrinos, the future RENO-50 experiment will search for more precise measurement of θ 12, Δm 2 12 and mass hierarchy.

We present a concise review of the theoretical status of neutrino oscillations within the (standard) 3-flavor framework and the (non-standard) 4-flavor scheme endowed with one additional sterile species (the so-called 3+1 scheme). We emphasize the slight overall preference that recently emerged for CP-violation in the 3-flavor analysis and highlight the unique role of the global data combination in the near future. After a brief introduction of the motivations for light (eV) sterile neutrinos, we discuss the bounds on their mixing with the electron neutrinos, attainable from the solar sector. The upper limit so obtained is independent of the reactor neutrino fluxes, whose calculations are affected by systematic uncertainties not completely under control. Finally, we highlight the possibility to explore sub-eV super-light sterile neutrinos exploiting the θ13-dedicated reactor experiments also commenting on the robustness of the 3- flavor results within the enlarged 3+1 scheme.

The Double Chooz reactor neutrino experiment will search for a non vanishing θ13 mixing angle with unprecedented sensitivity, which might open the way to unveiling CP violation in the leptonic sector. The measurement of this angle will be based in a precise comparison of the antineutrino spectrum at two identical detectors located at different distances from the Chooz nuclear reactor cores in France. Double Chooz is particularly attractive because of its capability to measure sin2(2θ13) to 3σ if sin2(2θ13) > 0.05 or to exclude sin2(2θ13) down to 0.03 at 90% C.L. for Δm231 = 2.5 × 10−3 eV2 in three years of data taking with both detectors. The installation of the far detector at 1 km from the reactors is almost completed and the first neutrino interactions are expected by end 2010.

The idea of using a neutrino detector to monitor nuclear reactors was first proposed in 1977 by L.A.Mikaelian. Tremendous progresses have been achieved since then in both detection technology and understanding of fundamental neutrino physics. This allows us to apply reactor antineutrino detection to thermal power measurement and survey of isotopic composition of reactor fuel. Here we present the Nucifer experiment, a 1 ton Gd-doped liquid scintillator detector to be installed a few 10 m from the core for reactor surveillance. The design of such a small surface detector has been focused on high detection efficiency (~50%) and good background rejection. Detailed simulations of reactor emitted antineutrino spectrum and detector response have been developed and used to calculate the Nucifer sensitivity to illicit retrieval of Pu from the core as it will be discussed. These results have been presented in October 2008 to the International Atomic Energy Agency (IAEA) which has expressed its interest in the potentialities of this detector as a new safeguard tool.

One of the goals of the KamLAND experiment is a search for anti-neutrino oscillation via inverse β decay with the characteristic delayed-coincidence method in the liquid scintillator. For a more precise measurement than previous KamLAND result [1], we have improved the background estimations of (α, n) and fast neutrons. We present the estimated number of backgrounds in our data set from Mar. 2002 to May 2007.