| 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(2
theta_{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. |
awa.tohoku.ac.jp 