The effect of nuclear recoil on neutrino oscillations: Toward understanding of short baseline anomalies

Abstract

We studied the structure of the neutrino wave functions produced in nuclear decays, with particular emphasis on the role of nuclear recoil. Although the fraction of the recoil energy associated with a nonzero neutrino mass is extremely small, it gives rise to a notable time-dependent flavor oscillation. For long-lived sources, such as those used in gallium anomaly and reactor anomaly experiments, this recoil-driven oscillation makes a substantial contribution to the observed deficit of (anti)neutrinos.