Laboratory constraints on peV-scale mass splitting between ordinary and sterile neutron states

N. J. Ayres; Z. Berezhiani; G. Bison; K. Bodek; V. Bondar; P. -J. Chiu; M. Daum; C. B. Doorenbos; S. Emmenegger; K. Kirch; V. Kletzl; J. Krempel; B. Lauss; D. Pais; I. Rienäcker; D. Ries; D. Rozpędzik; P. Schmidt-Wellenburg; K. S. Tanaka; J. Zejma; N. Ziehl; G. Zsigmond

arXiv · 2608.12173

Laboratory constraints on peV-scale mass splitting between ordinary and sterile neutron states

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Abstract

Sterile states of matter, represented by a parallel ``mirror'' sector, may contribute to the observed dark matter in the Universe. We investigated the parameter space of neutron $(n)$ to mirror-neutron $(n')$ oscillations, in the case where the two states are not necessarily mass-degenerate, taking into account interactions in the mirror sector. By tuning the magnitude of an applied magnetic-field in the range $5~\mu\mathrm{T} < B < 360~\mu\mathrm{T}$ to corresponding resonance conditions for finite mass splitting, we derive exclusion limits for the $n-n'$ oscillation time constant reaching about $20~\text{s}$ over the mass-difference range $0.3 - 22~\text{peV}$. In parts of this parameter range, our limits exceed the model-dependent neutron-star-cooling bound, providing the first experimental constraints in this scenario that are more stringent than this astrophysical estimate.

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N. J. Ayres, Z. Berezhiani, G. Bison, K. Bodek, V. Bondar, P. -J. Chiu, M. Daum, C. B. Doorenbos, S. Emmenegger, K. Kirch, V. Kletzl, J. Krempel, B. Lauss, D. Pais, I. Rienäcker, D. Ries, D. Rozpędzik, P. Schmidt-Wellenburg, K. S. Tanaka, J. Zejma, N. Ziehl, G. Zsigmond. 2026-08-12. Laboratory constraints on peV-scale mass splitting between ordinary and sterile neutron states. https://arxiv.org/abs/2608.12173

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