Measuring Nuclear Spin Dependent Parity Violation With Molecules: Experimental Methods and Analysis of Systematic Errors

Nuclear spin-dependent parity violation (NSD-PV) effects in atoms and molecules arise from $Z^0$ boson exchange between electrons and the nucleus, and from the magnetic interaction between electrons and the parity-violating nuclear anapole moment. It has been proposed to study NSD-PV effects using an enhancement of the observable effect in diatomic molecules [D. DeMille $\mathit{\text{et}}\mathit{\text{al.}}$, Phys. Rev. Lett. $\mathbf{\text{100}}$, 023003 (2008)]. Here, we demonstrate measurements of this type with sensitivity surpassing that of any previous atomic PV measurement, using the test system ${}^{138}\mathrm{B}{\mathrm{a}}^{19}\mathrm{F}$. We show that systematic errors associated with our technique can be suppressed to at least the level of the present statistical sensitivity. With $\sim \text{\hspace{0.17em}⁣}170$ hours of data, we measure the matrix element, $W$, of the NSD-PV interaction with uncertainty $\delta W\mathrm{/}(2\pi )<0.7$ Hz, for each of two configurations where $W$ must have different signs. This sensitivity would be sufficient to measure NSD-PV effects of the size anticipated across a wide range of nuclei.