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arXiv:0907.4179 · Physical Review A

Electron electric-dipole-moment searches based on alkali-metal- or alkaline-earth-metal-bearing molecules

Edmund Meyer, John L. Bohn

Published Oct 16, 2009• 55 citations
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Abstract

We introduce four new molecules---YbRb, YbCs, ${\text{YbSr}}^{+}$, and ${\text{YbBa}}^{+}$---that may prove fruitful in experimental searches for the electric-dipole moment (EDM) of the electron. These molecules can, in principle, be prepared at extremely low temperatures by photoassociating ultracold atoms and therefore may present an advantage over molecular-beam experiments. Here we discuss properties of these molecules and assess the effective electric fields they contribute to an electron EDM measurement.

DOI
10.1103/physreva.80.042508

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We propose an experiment to measure the electric dipole moment (EDM) of the electron using ultracold YbF molecules. The molecules are produced as a thermal beam by a cryogenic buffer gas source, and brought to rest in an optical molasses that cools them to the Doppler limit or below. The molecular cloud is then thrown upward to form a fountain in which the EDM of the electron is measured. A non-zero result would be unambiguous proof of new elementary particle interactions, beyond the standard model.
Abstract Recent improvements in experimental techniques for preparing ultracold molecules that contain alkali atoms (e.g. Li, Na, and K) have been reported. Based on these advances in ultracold molecules, new searches for the electric dipole moment of the electron and the scalar-pseudoscalar interaction can be proposed on such systems. We calculate the effective electric fields ( E eff ) and the scalar-pseudoscalar coefficients ( W s ) of SrA and HgA (A = Li, Na, and K) molecules at the Dirac–Fock (DF) and the relativistic coupled cluster (RCC) levels. We elaborate on the following points: (i) basis set dependence of the molecular properties in HgA, (ii) analysis of E eff and W s in SrA and HgA, and comparison with their fluoride and hydride counterparts, (iii) ratio of W s to E eff ( W s / E eff ) at the DF and the correlation RCC levels of theory.
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