Parity-nonconserving interactions of electrons in chiral molecules with cosmic fields

Parity (P)-violating pseudoscalar or pseudovector cosmic fields are invoked in different models for cold dark matter or in the standard model extension that allows for Lorentz invariance violation. A direct detection of the timelike component of such fields requires a direct measurement of P-odd potentials or their evolution over time. Herein, advantageous properties of chiral molecules, in which P-odd potentials lead to resonance frequency differences between enantiomers, for direct detection of such P-odd cosmic field interactions are demonstrated. Scaling behavior of electronic structure enhancements of such interactions with respect to nuclear charge number and the fine-structure constant is derived analytically. This allows a simple estimate of the effect sizes for arbitrary molecules. The analytical derivation is supported by quasirelativistic numerical calculations in the molecules H2X2 and H2XO with X = O, S, Se, Te, or Po. Parity-violating effects due to cosmic fields on the C-F stretching mode in CHBrC1F are compared to electroweak parity violation and influences of nonseparable anharmonic vibrational corrections are discussed. On this basis, Gaul et al. [1 3 11).s. Rev. Lett. 125, 123004 (202'))] estimated from a 20-year-old experiment with CHBrC1F that bounds on Lorentz invariance violation as characterized by the parameter vertical bar b(0)(e)vertical bar can be pushed down to the order of 10(-17) GeV in modern experiments with suitably selected molecular system, which will be an improvement of the current best limits by at least two orders of magnitude. This serves to highlight the particular opportunities that precision spectroscopy of chiral molecules provides in the search for new physics beyond the standard model.