Physics Paradigm Challenge

Scientists are looking for 'mirror' neutrons that can literally phase out of our world and slip into a parallel dimension.

March 27, 2026

Original Paper

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

Gaby Brenot, Benoit Clément, Hanno Filter-Pieler, Daniel Galbinski, Tobias Jenke, Thomas Lefort, Anthony Lejuez, Guillaume Pignol, Stephanie Roccia, William Saenz-Arevalo

arXiv · 2603.25376

The Takeaway

Researchers used a beam of ultracold neutrons to search for oscillations into a 'hidden' state, which would look like particles simply disappearing into thin air. If found, these mirror particles would prove the existence of a 'hidden sector' of the universe that interacts with ours only through gravity and specific quantum transitions.

From the 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 pro