A search for neutron to mirror-neutron oscillations using the nEDM apparatus at PSI

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18 Scopus citations

Abstract

It has been proposed that there could be a mirror copy of the standard model particles, restoring the parity symmetry in the weak interaction on the global level. Oscillations between a neutral standard model particle, such as the neutron, and its mirror counterpart could potentially answer various standing issues in physics today. Astrophysical studies and terrestrial experiments led by ultracold neutron storage measurements have investigated neutron to mirror-neutron oscillations and imposed constraints on the theoretical parameters. Recently, further analysis of these ultracold neutron storage experiments has yielded statistically significant anomalous signals that may be interpreted as neutron to mirror-neutron oscillations, assuming nonzero mirror magnetic fields. The neutron electric dipole moment collaboration performed a dedicated search at the Paul Scherrer Institute and found no evidence of neutron to mirror-neutron oscillations. Thereby, the following new lower limits on the oscillation time were obtained: τnn>352 s at B=0 (95% C.L.), τnn>6s for 0.4μT<B<25.7μT (95% C.L.), and τnn/cos⁡β>9s for 5.0μT<B<25.4μT (95% C.L.), where β is the fixed angle between the applied magnetic field and the local mirror magnetic field, which is assumed to be bound to the Earth. These new constraints are the best measured so far around B∼10μT and B∼20μT.

Original languageEnglish
Article number135993
JournalPhysics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Volume812
DOIs
StatePublished - Jan 10 2021

Bibliographical note

Funding Information:
We especially thank Z. Berezhiani for many valuable suggestions. The authors greatly acknowledge the exceptional support provided by Michael Meier, Fritz Burri and the BSQ group at PSI. The LPC and LPSC groups were supported by ANR (FR) grant # ANR-14-CE33-0007-02. The University of Sussex (UK) group was supported by STFC grants #ST/N504452/1, ST/M003426/1, and ST/N000307/1, and by their School of Mathematical and Physical Sciences. The PSI group was supported by the Swiss SNSF grants # 200020-137664, # 200021-117696, # 200020-144473, # 200021-126562, # 200020-163413 and # 200021-157079. ETHZ was supported by SNSF grant # 200020-172639. The University of Fribourg group was supported by SNSF grant # 200020-140421. The University of Bern group was supported by the grants SNSF # 181996 and ERC (EU) # 715031-BEAM-EDM. The Jagiellonian University group was supported by the Polish National Science Center grant # 2015/18/M/ST2/00056, # 2016/23/D/ST2/00715 and # 2018/30/M/ST2/00319. For the KU Leuven group, this work is also partly supported by Project GOA/2010/10 and Fund for Scientific Research in Flanders (FWO). One of the authors, P.M. would like to acknowledge support from the SERI-FCS (CH) award # 2015.0594 and Sigma Xi (USA) grants # G2017100190747806 and # G2019100190747806. We would like to acknowledge the grid computing resource provided by PL-GRID [58].

Funding Information:
We especially thank Z. Berezhiani for many valuable suggestions. The authors greatly acknowledge the exceptional support provided by Michael Meier, Fritz Burri and the BSQ group at PSI. The LPC and LPSC groups were supported by ANR (FR) grant # ANR-14-CE33-0007-02 . The University of Sussex (UK) group was supported by STFC grants # ST/N504452/1 , ST/M003426/1 , and ST/N000307/1 , and by their School of Mathematical and Physical Sciences . The PSI group was supported by the Swiss SNSF grants # 200020-137664 , # 200021-117696 , # 200020-144473 , # 200021-126562 , # 200020-163413 and # 200021-157079 . ETHZ was supported by SNSF grant # 200020-172639 . The University of Fribourg group was supported by SNSF grant # 200020-140421 . The University of Bern group was supported by the grants SNSF # 181996 and ERC (EU) # 715031-BEAM-EDM . The Jagiellonian University group was supported by the Polish National Science Center grant # 2015/18/M/ST2/00056 , # 2016/23/D/ST2/00715 and # 2018/30/M/ST2/00319 . For the KU Leuven group, this work is also partly supported by Project GOA/2010/10 and Fund for Scientific Research in Flanders (FWO). One of the authors, P.M., would like to acknowledge support from the SERI-FCS (CH) award # 2015.0594 and Sigma Xi (USA) grants # G2017100190747806 and # G2019100190747806 . We would like to acknowledge the grid computing resource provided by PL-GRID [58] .

Publisher Copyright:
© 2020 The Authors

Keywords

  • Dark matter
  • Mirror matter
  • Nuclear matter
  • Particle symmetries
  • Properties of neutrons
  • Ultracold neutrons

ASJC Scopus subject areas

  • Nuclear and High Energy Physics

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