Further search for magnetic-field-induced neutron disappearance in an ultracold neutron beam
We report the results of the second iteration of an experiment searching for neutron-hidden-neutron oscillations in a beam of ultracold neutrons, conducted at the PF2 facility of the Institut Laue Langevin (ILL). Oscillations were tested via neutron disappearance as a function of an applied magnetic field, in the context of a phenomenological two-parameter model assuming zero hidden potentials. The magnetic field was varied in a step-wise manner in order to resonantly enhance the oscillation probability at different mass splittings ($δm$) across a 60--1550 peV range. No evidence for neutron disappearance is observed and conservative limits on the neutron-hidden-neutron oscillation period ($τ_{nn'}$) have been set at 95 % confidence level: $τ_{nn'} > 200$ms for $|δm| \in [60, 400]$ peV and $τ_{nn'} > 100$ ms for $|δm| \in [400, 1550]$ peV