Date of Award
Spring 2023
Document Type
Dissertation
Degree Name
Doctor of Philosophy (PhD)
Department
Physics
First Advisor
Lamoreaux, Steve
Abstract
The observed matter-antimatter asymmetry of the universe is widely considered to be an indication of the existence of beyond the Standard Model time-reversal symmetry violating physics. This dissertation describes work on a new molecular beam experiment (CeNTREX) to search for T-violating physics in the hyperfine structure of the diatomic molecule thallium fluoride ($^{205}$Tl$^{19}$F). TlF is primarily sensitive to T-violating physics due to the Schiff moment of the thallium nucleus. Thus, our experimental scheme is to search for a change in the nuclear magnetic resonance frequency of the Tl nucleus when the direction of an electric field coupled to the Schiff moment is reversed. CeNTREX will improve on older experiments using TlF by utilizing a cryogenic buffer gas beam source to produce a cold and slowly moving beam of TlF, advances in microwave technology for state manipulation, and optical transitions for rotational cooling and detection. Together these enhancements are expected to improve the sensitivity to T-violating interactions in TlF by approximately three orders of magnitude over the previous best limit, thus setting new bounds on the Schiff moment of Tl, and on related quantities such as the electric dipole moment of the proton. This is expected to make CeNTREX competitive with current state of the art experiments searching for flavor-conserving T-violation in the hadronic sector. This thesis presents progress on various modules of the experiment. Experimental results from characterizing the TlF cryogenic buffer gas beam source are presented. We also report an improved measurement of the gain in useful molecular population due to a rotational cooling scheme utilizing optical pumping and microwave driven rotational transitions. Rotational state preparation using microwave driven adiabatic passage in a spatially-varying electric field is discussed, and experimental results are presented. The design of an electrostatic lens to guide the trajectories of molecules emerging from the beam source is also presented.
Recommended Citation
Timgren, Oskari Matinpoika, "Progress towards a measurement of time-reversal symmetry violation in thallium fluoride" (2023). Yale Graduate School of Arts and Sciences Dissertations. 1080.
https://elischolar.library.yale.edu/gsas_dissertations/1080
