Limits onνeandν¯edisappearance from Gallium and reactor experiments

Abstract

The deficit observed in the Gallium radioactive source experiments is interpreted as a possible indication of the disappearance of electron neutrinos. In the effective framework of two-neutrino mixing we obtain ${sin}^{2}2\vartheta \gtrsim 0.03$ and $\Delta m^2\gtrsim 0.1{\mathrm{eV}}^2$. The compatibility of this result with the data of the Bugey and Chooz reactor short-baseline antineutrino disappearance experiments is studied. It is found that the Bugey data present a hint of neutrino oscillations with $0.02\lesssim {sin}^{2}2\vartheta \lesssim 0.08$ and $\Delta m^2\approx 1.8{\mathrm{eV}}^2$, which is compatible with the Gallium allowed region of the mixing parameters. This hint persists in the combined analyses of Bugey and Chooz data, of Gallium and Bugey data, and of Gallium, Bugey, and Chooz data.