Further search for magnetic-field-induced neutron disappearance in an ultracold neutron beam

Abstract

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 ($\delta m$) across a 60--1550 peV range. No evidence for neutron disappearance is observed and conservative limits on the neutron-hidden-neutron oscillation period (${\tau }_{n{n}^{\prime }}$) have been set at 95 % confidence level: ${\tau }_{n{n}^{\prime }}>200$ms for $|\delta m|\in [60,400]$ peV and ${\tau }_{n{n}^{\prime }}>100$ ms for $|\delta m|\in [400,1550]$ peV

8 pages, 4 figures