Statistics and systematics of electron EDM searches with BaF

A. Boeschoten; V. R. Marshall; T. B. Meijknecht; A. P. Touwen; P. Aggarwal; N. Balasubramanian; R. Bause; H. L. Bethlem; A. Borschevsky; T. H. Fikkers; P. A. B. Haase; Y. Hao; S. Hoekstra; J. W. F. van Hofslot; S. A. Jones; K. Jungmann; J. E. J. Levenga; M. C. Mooij; H. Mulder; B. A. Nijman; E. H. Prinsen; B. J. Schellenberg; I. E. Thompson; R. G. E. Timmermans; L. van Sloten; W. Ubachs; J. de Vries; L. Willmann; Y. Yin

doi:10.1140/epjd/s10053-026-01175-2

2025 Impact factor 1.8

Atomic, Molecular, Optical and Plasma Physics

Open Access

Eur. Phys. J. D (2026) 80: 62
https://doi.org/10.1140/epjd/s10053-026-01175-2

Research - Atoms, Molecules, Ions, and Clusters

Statistics and systematics of electron EDM searches with BaF

A. Boeschoten¹^,2, V. R. Marshall¹^,2, T. B. Meijknecht¹^,2, A. P. Touwen¹^,2, P. Aggarwal¹^,2, N. Balasubramanian¹^,2, R. Bause¹^,2, H. L. Bethlem¹^,3, A. Borschevsky¹^,2, T. H. Fikkers¹^,2, P. A. B. Haase¹^,2, Y. Hao¹, S. Hoekstra¹^,2, J. W. F. van Hofslot¹^,2, S. A. Jones¹^,2, K. Jungmann¹, J. E. J. Levenga¹^,2, M. C. Mooij²^,3, H. Mulder¹^,2, B. A. Nijman¹^,2, E. H. Prinsen¹^,2, B. J. Schellenberg¹^,2, I. E. Thompson¹^,2, R. G. E. Timmermans¹^,2, L. van Sloten¹^,2, W. Ubachs³, J. de Vries²^,4, L. Willmann¹^,2^a and Y. Yin¹^,2

¹ Van Swinderen Institute for Particle Physics and Gravity (VSI), University of Groningen, Nijenborgh 3, 9747 AG, Groningen, The Netherlands
² Nikhef, National Institute for Subatomic Physics, Science Park 105, 1098 XG, Amsterdam, The Netherlands
³ Department of Physics and Astronomy, LaserLaB, Vrije Universiteit, De Boelelaan 1100, 1081 HZ, Amsterdam, The Netherlands
⁴ Institute for Theoretical Physics, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands

^a This email address is being protected from spambots. You need JavaScript enabled to view it.

Received: 29 December 2025
Accepted: 27 April 2026
Published online: 19 May 2026

Abstract

The NL-eEDM experiment searches for a nonzero electric dipole moment of the electron $d_{e}$ Mathematical equation: $$d_e$$ (eEDM) in the ground state of barium monofluoride (BaF). A beam of BaF from a supersonic expansion source is probed with the spin-precession method presented in Boeschoten et al. (Phys Rev A 110:L010801, 2024). This method permits the extraction of an eEDM value as well as values for parameters causing a possible systematic bias leading to a false eEDM. The currently achievable sensitivity is limited by statistics collected in a period of 34 h and yields an $d_{e}$ Mathematical equation: $$d_e$$ of $2 (3) \times 10^{- 25}$ $Mathematical equation: $$2(3) \times 10^{-25}$$$ $e$ $Mathematical equation: $$e\,$$$ cm. Furthermore, from the same dataset sufficiently strong limits on parameters which can induce a false eEDM are extracted. These are mainly the electric field E and the intensity of the lasers fields in the fiducial volume of the experiment. We summarize the steps required to upgrade of the experiment to reach a competitive level on $d_{e}$ Mathematical equation: $$d_e$$ , e.g., an intense laser-cooled beam from a cryogenic buffer gas source and the light collection efficiency of fluorescence.

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Statistics and systematics of electron EDM searches with BaF

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