Precision measurements of parity violation using trapped neutral molecules

One of the main driving forces of physics is the search for the most fundamental laws of nature. In PRIME-MOL, I will expand our understanding of these fundamental laws by trapping laser-cooled molecules and using them as precision sensors.Molecules have become pivotal tools in precision measurement science, offering exceptional opportunities for advanced spectroscopy and tests of fundamental symmetries. This can provide unique insights that complement those from experiments at large collider facilities and has raised hopes of discovering new physics beyond the Standard Model of particle physics in so far unexplored regimes.I will explore a regime where existing insights are both scarce and conflicting, offering a high potential for groundbreaking discoveries: the electroweak sector of the Standard Model. I will probe weak nuclear-spin-dependent parity violation, where notable tension persists between the only previous low-energy experiment with atoms and high-energy experiments, highlighting important gaps in our understanding. Molecules can enhance such parity-violating effects by orders of magnitude, making them an ideal platform to answer open questions by probing the underlying physics and potential new particles with unprecedented precision.However, achieving this requires the trapping of suitable molecules, which is a major challenge due to their heavy mass and complex level structure. So far, experiments have therefore relied on molecular beams, where the achievable sensitivity is severely constrained by short probe times and limited quantum control. In PRIME-MOL, I will pioneer a new class of precision experiments using trapped neutral molecules, disrupting existing limitations by capitalizing on very recent breakthrough achievements in laser cooling of heavy barium monofluoride molecules. This will open new avenues for probing symmetry-violating phenomena and advance our understanding of particles and interactions at the most fundamental level.