Systematic study and uncertainty evaluation of \(P,T\)-odd molecular enhancement factors in BaF

• Published in: arXiv.org
• Main Authors: Haase, Pi A B, Doeglas, Diewertje J, Boeschoten, Alexander, Eliav, Ephraim, Iliaš, Miroslav, Aggarwal, Parul, Bethlem, Hendrick L, Borschevsky, Anastasia, Esajas, Kevin, Hao, Yongliang, Hoekstra, Steven, Marshall, Virginia R, Meijknecht, Thomas B, Mooij, Maarten C, Steinebach, Kees, Timmermans, Rob G E, Anno Touwen, Ubachs, Wim, Willmann, Lorenz, Yin, Yanning
• Format: Paper
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 03.05.2021
• Subjects: Diatomic molecules; Dipole moments; Electric dipoles; Electronic structure; Fields (mathematics); Heavy elements; Parameter estimation; Parameter uncertainty; Particle physics; Relativistic effects; Sensitivity enhancement; Standard model (particle physics)
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.2105.01132

A measurement of the magnitude of the electric dipole moment of the electron (eEDM) larger than that predicted by the Standard Model (SM) of particle physics is expected to have a huge impact on the search for physics beyond the SM. Polar diatomic molecules containing heavy elements experience enhanced sensitivity to parity (\(P\)) and time-reversal (\(T\))-violating phenomena, such as the eEDM and the scalar-pseudoscalar (S-PS) interaction between the nucleons and the electrons, and are thus promising candidates for measurements. The NL-\textit{e}EDM collaboration is preparing an experiment to measure the eEDM and S-PS interaction in a slow beam of cold BaF molecules [Eur. Phys. J. D, 72, 197 (2018)]. Accurate knowledge of the electronic structure parameters, \(W_d\) and \(W_s\), connecting the eEDM and the S-PS interaction to the measurable energy shifts is crucial for the interpretation of these measurements. In this work we use the finite field relativistic coupled cluster approach to calculate the \(W_d\) and \(W_s\) parameters in the ground state of the BaF molecule. Special attention was paid to providing a reliable theoretical uncertainty estimate based on investigations of the basis set, electron correlation, relativistic effects and geometry. Our recommended values of the two parameters, including conservative uncertainty estimates, are 3.13 \(\pm\) \(0.12 \times 10^{24}\frac{\text{Hz}}{e\cdot \text{cm}}\) for \(W_d\) and 8.29 \(\pm\) 0.12 kHz for \(W_s\).