Status and Progress Toward a Measurement of the ²⁰⁵Tl Nuclear Schiff Moment in TlF with CeNTREX

The Cold molecule Nuclear Time-Reversal EXperiment (CeNTREX) is a search for time-reversal and parity violation in the hadronic sector through a measurement of the nuclear Schiff moment of ²⁰⁵Tl using thallium fluoride (TlF) molecules. The strong internal electric fields of polar molecules provide enhanced sensitivity to CP-violating interactions, with the promise to enable competitive constraints on QCD, quark chromo-electric dipole moments, and the proton electric dipole moment.

CeNTREX combines a cryogenic molecular beam source with optical and microwave techniques for quantum-state preparation, manipulation, and detection. Rotational cooling concentrates population into a single hyperfine level of the J=0 ground state. A State Preparation module transfers population from this state to weak-field-seeking J=2 states required for electrostatic focusing. Transverse focusing of the molecular beam is achieved using an electrostatic quadrupole lens (EQL), increasing molecular flux through downstream regions of the experiment.

We report recent status and progress on the implementation and characterization of the EQL, including measurements of beam focusing and transmission. Following electrostatic focusing, A second State Preparation module uses microwave adiabatic passage in spatially varying electric fields to coherently transfer population into the J=1 quantum state used for the Schiff moment measurement. Before and after this module, State Cleanup stages are used to remove residual population in unwanted quantum states and reduces backgrounds for downstream detection and measurement.

Together, these results demonstrate several of the required, complex protocols for quantum-state preparation and manipulation in CeNTREX; they represent important milestones toward a first nuclear Schiff moment measurement in ²⁰⁵TlF.