Towards beyond-Standard Model searches with ultracold SrOH molecules*

Polyatomic molecules offer a powerful platform for precision measurements of physics beyond the Standard Model due to their complex structures. The near-degenerate vibrational states in the triatomic molecule SrOH can be used to probe candidate dark matter particles: since the energy levels of these states depend differently on the proton-to-electron mass ratio, μ, microwave resonance spectroscopy between them is highly sensitive to possible fluctuations in μ that would be induced by a broad class of ultralight scalar dark matter fields. Long-lived, easily polarized states in SrOH also enable a probe for the electron electric dipole moment. We report on work toward the laser cooling and trapping of SrOH. We have carried out spectroscopy of the vibrational states used in the proposed laser cooling scheme, where a molecule can scatter more than 10,000 photons before being lost in an unaddressed state.