Sensitivity to Dark Matter Couplings from Frequency Measurements of Acetylene Optical Clocks

SummaryCouplings of ultralight dark matter candidates to the particles of the Standard Model leading to time variations of the fundamental constants are addressed through measurements of acetylene optical clock transitions. The sensitivity to couplings of ultralight dark matter candidates in the mass range 4.6×10
⁻¹⁵
–4.6 × 10
⁻⁶
eV to electrons and photons is evaluated by comparing sub-Doppler and linear absorption
¹²
C
2
H
2
lines of the v
1
+v
3
band to a Fabry-Perot cavity-stabilized laser.