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

arXiv · 2601.21781

Statistics and systematics of electron EDM searches with BaF

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Abstract

The NL-$e$EDM experiment searches for a non-zero electric dipole moment of the electron $d_e$ ($e$EDM) 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 \cite{Boeschoten2024}. This method permits the extraction of an $e$EDM value as well as values for parameters causing a possible systematic bias leading to a false $e$EDM. The currently achievable sensitivity is limited by statistics collected in a period of 34 hours and yields an $d_e$ of $2(3) \times 10^{-25}$ $e\,$cm. Furthermore, from the same dataset sufficiently strong limits on parameters which can induce a false $e$EDM are extracted. These are mainly the electric field \textbf{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 $d_e$, e.g. an intense laser-cooled beam from a cryogenic buffer gas source and the light collection efficiency of fluorescence.

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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. 2026-01-29. Statistics and systematics of electron EDM searches with BaF. https://arxiv.org/abs/2601.21781

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