Thierry Lasserre (CEA-Saclay)
Testing the Reactor Antineutrino Anomaly with a 10g 144Ce-144Pr source deployed inside a Large Liquid Scintillator Detector
Abstract: Recently new reactor antineutrino spectra have been provided for 235U, 239Pu, 241Pu and 238U, increasing the mean flux by about 3 percent. With the new flux evaluation the synthesis of published experiments at reactor-detector distances <100 m leads to a ratio of 0.943(0.023), leading to a deviation from unity at 98.6% C.L. that we call the reactor antineutrino anomaly. The compatibility of our results with the existence of a fourth non-standard neutrino state driving neutrino oscillations at short distances will be discussed. The combined analysis of reactor data, gallium solar neutrino calibration experiments disfavors the no-oscillation hypothesis at 99.8% C.L. The oscillation parameters are such that |Delta m_{new}^2|>1.5 eV^2 (99%) and sin^2(2theta_{new}) = 0.14(0.1) (95%). I will show that this hypothesis can be tested with a PBq (ten kilocurie scale) 144Ce or 106Ru antineutrino beta-source deployed at the center of a large low background liquid scintillator detector. In particular, the compact size of such a source could yield an energy-dependent oscillating pattern in event spatial distribution that would unambiguously determine neutrino mass differences and mixing angles.