Gallium and Reactor Neutrino Anomalies

Abstract

The observed deficit in the Gallium radioactive source experiments may be interpreted as a possible indication of active-sterile ν e mixing. In the effective framework of two-neutrino mixing we obtain sin 2 2 ϑ ≳ 0.03 and Δ m 2 ≳ 0.1 eV 2 . The compatibility of this result with the data of the Bugey reactor ν ¯ e disappearance experiments is studied. It is found that the Bugey data present a hint of neutrino oscillations with 0.02 ≲ sin 2 2 ϑ ≲ 0.08 and Δ m 2 ≈ 1.8 eV 2 , which is compatible with the Gallium allowed region of the mixing parameters. This hint persists in the combined analysis of Gallium, Bugey, and Chooz data.