Orateur
Dr
Guillaume MENTION
(CEA Saclay)
Description
Recently new reactor antineutrino spectra have been provided for 235U, 239Pu, 241Pu and 238U, increasing the mean flux by about 3 percent. To good approximation, this reevaluation applies to all reactor neutrino experiments. The synthesis of published experiments at reactor-detector distances ≤ 100 m leads to a ratio of observed event rate to predicted rate of 0.979(0.029). With our new flux evaluation, this ratio shifts to 0.937(0.027), leading to a deviation from unity at 98.4% C.L. which 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 is discussed. The combined analysis of reactor data, gallium solar neutrino calibration experiments, and MiniBooNE-neutrino data disfavors the no-oscillation hypothesis at 99.93% C.L. The oscillation parameters are such that |∆m^2| ≥ 1.5eV^2 (99% C.L.) and sin^2(2θ) = 0.17(0.1) (95% C.L.). Constraints on the theta13 neutrino mixing angle are revised.
Auteur principal
Dr
Guillaume MENTION
(CEA Saclay)
