We present the design of a next-generation experiment, n2EDM, currently under construction at the ultracold neutron source at the Paul Scherrer Institute (PSI) with the aim of carrying out a high-precision search for an electric dipole moment of the neutron. The project builds on experience gained with the previous apparatus operated at PSI until 2017, and is expected to deliver an order of magnitude better sensitivity with provision for further substantial improvements. An overview is of the experimental method and setup is given, the sensitivity requirements for the apparatus are derived, and its technical design is described.

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Published in The European Physical Journal C, v. 81, article no. 512.

© The Author(s) 2021

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Due to the large number of authors, only the first 20 (including the author affiliated with the University of Kentucky) are listed in the author section above. For the complete list of authors, please download this article.

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We are grateful for financial support from the the Swiss National Science Foundation through projects 200020-188700 (PSI), 200020-137664 (PSI), 200021-117696 (PSI), 200020-144473 (PSI), 200021-126562 (PSI), 200021-181996 (Bern), 200020-172639 (ETH), R’EQUIP under numbers 139140 and 177008 and FLARE 20FL21-186179. The support by Emil-Berthele-Fonds is acknowledged. The LPC Caen and the LPSC Grenoble acknowledge the support of the French Agence Nationale de la Recherche (ANR) under reference ANR-14-CE33-0007 and the ERC project 716651-NEDM. The Polish collaborators acknowledge support from the National Science Center, Poland, Grants no. 2015/18/M/ST2/00056, no. 2018/30/M/ST2/00319, no. 2016/23/D/ST2/00715 and no. 2020/37/B/ST2/02349. Support by the Cluster of Excellence “Precision Physics, Fundamental Interactions, and Structure of Matter” (PRISMA & EXC 2118/1) funded by the German Research Foundation (DFG) within the German Excellence Strategy (Project ID 39083149) is acknowledged. This work was partly supported by the Fund for Scientific Research Flanders (FWO) and Project GOA/2010/10 of the KU Leuven. The Core Facility ”Metrology of Ultra-Low Magnetic Fields” at PTB was funded by Deutsche Forschungsgemeinschaft (DFG) through funding codes: DFG KO 5321/3-1 and TR408/11-1.

Funded by SCOAP3.

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