Reconciling results of LSND, MiniBooNE and other experiments with soft decoherence

Abstract

We propose an explanation of the LSND signal via quantum-decoherence of the mass states, which leads to damping of the interference terms in the oscillation probabilities. It is assumed that decoherence mainly affects the state ν 3 (oscillations with the atmospheric Δm 2) and damping effects rapidly decrease with the neutrino energy (the decoherence parameter γE ν-4). This allows us to reconcile the positive LSND signal with MiniBooNE and other null-result experiments. The standard explanations of solar, atmospheric, KamLAND and MINOS data are not affected. No new particles, and in particular, no sterile neutrinos are needed. The model does not explain the low-energy MiniBooNE anomaly and does not resolve the LSND-KARMEN tension. The LSND signal is controlled by the 1-3 mixing angle θ 13 and, depending on the degree of damping, yields 0.0014 <0.034 at 3σ. The scenario can be tested at upcoming θ 13 searches: while the comparison of near and far detector measurements at reactors should lead to a null-result a positive signal for θ 13 is expected in long-baseline accelerator experiments. The proposed decoherence may partially explain the results of Gallium detector calibrations and it can strongly affect supernova neutrino signals.