New high-sensitivity search for neutron to mirror-neutron oscillations at the PSI UCN source

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. Rozpedzik; P. Schmidt-Wellenburg; K. S. Tanaka; J. Zejma; N. Ziehl; G. Zsigmond

arXiv · 2602.23487

New high-sensitivity search for neutron to mirror-neutron oscillations at the PSI UCN source

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Abstract

In a search for potential signals of neutron (n) to mirror-neutron (n') oscillations, a collaboration centered at the Paul Scherrer Institute (PSI) investigated the remaining parameter space claimed by anomalies with a dedicated high-sensitivity apparatus. An elaborate magnetic-field-mapping analysis and Monte Carlo simulation of the cumulative n-n' oscillation probabilities along the neutron trajectories inside the storage vessel complemented the neutron data analysis. Magnetic fields were scanned in the range 5 microT < B < 109 microT. No evidence of anomalous neutron losses was found. Consequently, new limits for the n-n' oscillation time constant were set. The parameter space, previously claimed for potential signals, has been excluded to 99.98 %.

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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. Rozpedzik, P. Schmidt-Wellenburg, K. S. Tanaka, J. Zejma, N. Ziehl, G. Zsigmond. 2026-02-26. New high-sensitivity search for neutron to mirror-neutron oscillations at the PSI UCN source. https://arxiv.org/abs/2602.23487

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