In a paper recently published in European Physical Journal (EPJ) C, researchers hypothesised the existence of mirror particles to explain the anomalous¹（异常的） loss of neutrons³ observed experimentally. The existence of such mirror matter had been suggested in various scientific contexts some time ago, including the search for suitable dark matter candidates. Theoretical physicists⁴ Zurab Berezhiani and Fabrizio Nesti from the University of l'Aquila, Italy, reanalysed the experimental data obtained by the research group of Anatoly Serebrov at the Institut Laue-Langevin, France. It showed that the loss rate of very slow free neutrons appeared to depend on the direction and strength of the magnetic field applied⁵. This anomaly could not be explained by known physics.

Berezhiani believes it could be interpreted in the light of a hypothetical parallel world consisting of mirror particles. Each neutron² would have the ability to transition into its invisible mirror twin, and back, oscillating from one world to the other. The probability of such a transition happening was predicted to be sensitive to the presence of magnetic fields, and could therefore be detected experimentally.

This neutron-mirror-neutron oscillation（振动） could occur within a timescale of a few seconds, according to the paper. The possibility of such a fast disappearance⁶ of neutrons -- much faster than the ten-minute long neutron decay -- albeit⁷ surprising, could not be excluded by existing experimental and astrophysical（天体物理学的） limits.

This interpretation⁸ is subject to the condition that the earth possesses a mirror magnetic field on the order of 0.1 Gauss. Such a field could be induced by mirror particles floating around in the galaxy⁹ as dark matter. Hypothetically, the earth could capture the mirror matter via some feeble（微弱的） interactions between ordinary particles and those from parallel worlds.