University of Colorado, Boulder
To measure the electron electric dipole moment (EDM) to an accuracy of better than 8x10-31 e-cm, and to characterize systematic errors in trapped-molecule EDM experiments for the benefit of next-generation experiments
Funds from this grant provide continuing support for efforts by researchers at JILA/University of Colorado, Boulder to build advanced instrumentation capable of detecting new fundamental particles through precision measurement of the distortions these particles cause to the distribution of electric charge in an electron. A team led by JILA Fellows Eric Cornell and Jun Ye will use laboratory-generated electric fields to trap and hold molecular ions, which can then be measured to detect deformations in their electrical charge. Held still, ions can be monitored for thousands of times longer than if they were in motion, thereby increasing the probability of a successful detection of a charge-distorting particle. Prior efforts using this technique by Cornell and Ye have successfully yielded a new upper limit on EDM measurement in 2023. Using Sloan funds, the team seeks to improve upon their prior, successful efforts in several ways. First, they will switch from hafnium fluoride (HfF+) to thorium fluoride ions (ThF+) as the primary ion used for detection. This will result in greater sensitivity, as thorium is known to be more sensitive to the sorts of electrical distortions the group is attempting to measure. Second, Cornell and Ye will work to boost the ‘coherence time’ of the molecules in their experiment. This represents the time interval during which the molecules remain in well-defined, laser-prepared energy states that are useful for an eEDM measurement. Finally, the group will experiment with a number of approaches that promise to boost the number of ions that can be measured at one time from a few thousand to a few hundred thousand. Taken together, the improvements are expected to increase the sensitivity of their prior measurement by a factor of 4. In parallel, Cornell and Ye will study the systematic errors associated with their trapped-molecules approach to EDM measurement with a focus on determining the root causes of systematic errors they encounter as well as determining the factors that affect the magnitude of those errors.