Sensitivity of the YbOH molecule to PT-odd effects in an external electric field

An electron electric dipole moment (eEDM) search using laser-coolable triatomics such as YbOH is one of the most sensitive probes for physics beyond the standard model. The eEDM-induced energy shift is proportional to the polarization (P) of the molecule. Similarly to diatomics with an ???-doubling structure, it was assumed that for triatomics with an l-doubling structure, related to the vibrational angular momentum, P can be easily saturated to almost 100% with a moderate external electric field. We developed a method for the calculation of the properties of triatomic molecules and applied it to a calculation of P of 174YbOH in the first excited v = 1 bending mode. Calculations showed that most of the levels reach less than 50% efficiency. We showed that this fact is related to the Hund???s case b coupling scheme of YbOH. As the coupling scheme (for ??? = 1/2 molecules) approaches the a (or c) case, polarization increases up to 100%. The results of our calculations should be used for the correct extracting of the eEDM value from YbOH experiments and similar calculations are required for other molecules.

Automated summary

An electron electric dipole moment (eEDM) search using laser-coolable triatomics such as YbOH is a sensitive probe for physics beyond the standard model. The study found that the polarization efficiency of triatomic molecules is usually less than 50%, which is related to the Hund's b coupling scheme.