Magnetic anomaly in UCN trapping: signal for neutron oscillations to parallel world?

Present experiments do not exclude that the neutron (n) oscillates into its invisible degenerate twin from a parallel world, so called mirror neutron (n'), with an appreciable probability. These oscillations were studied experimentally by monitoring the neutron losses in ultra-cold neutron traps, where they can be revealed by the magnetic field dependence of n-n' transition probability. In this work we reanalyze the experimental data acquired by the group of A.P. Serebrov at Institute Laue-Langevin, and find a dependence at more than 5-sigma away from the null hypothesis. This anomaly can be interpreted as oscillation to mirror neutrons with a timescale of few seconds, in the presence of a mirror magnetic field B' of about 0.1 G at the Earth. This result, if confirmed by future experiments, will have deepest consequences for fundamental particle physics, astrophysics and cosmology.