Experimental Constraint on Axionlike Particles over Seven Orders of Magnitude in Mass

We use our recent electric dipole moment (EDM) measurement data to constrain the possibility that the ${\mathrm{HfF}}^{+}$ EDM oscillates in time due to interactions with candidate dark matter axionlike particles (ALPs). We employ a Bayesian analysis method which accounts for both the look-elsewhere effect and the uncertainties associated with stochastic density fluctuations in the ALP field. We find no evidence of an oscillating EDM over a range spanning from 27 nHz to 400 mHz, and we use this result to constrain the ALP-gluon coupling over the mass range ${10}^{-22}–{10}^{-15}\mathrm{eV}$. This is the first laboratory constraint on the ALP-gluon coupling in the ${10}^{-17}–{10}^{-15}\mathrm{eV}$ range, and the first laboratory constraint to properly account for the stochastic nature of the ALP field.

Figure 1

Least-squares spectral analysis of our EDM data.

Figure 2

Bayesian power measured analysis of the EDM data. The gray scale matrix corresponds to a subaggregation of the prior updates $U$ over 100 logarithmically spaced frequency bins. Darker shading on the logarithmic color scale corresponds to increased prior update, which can be interpreted as an increased belief in an ALP of given frequency $\nu$ at ALP-gluon coupling $C_G/(f_a{m}_a)$. We use a blue line to indicate the 95% exclusion (which corresponds to the subaggregated update dropping to 0.05 [42]) for subaggregation over each decade. The corresponding gray scale matrix for this subaggregation is not shown. Finally, a dotted line corresponds to the aggregated exclusion over the full analysis range. The full un-aggregated matrix of $U$ values is available upon request.

Figure 3

Astrophysical and laboratory limits on the ALP-gluon interaction. All limits assume that ALPs saturate the local dark matter content and we have taken the mean local dark matter density to be $0.4{\mathrm{GeV}/\mathrm{cm}}^3$ [45]. All constraints correspond to a 95% confidence level. The purple region embodies the constraint that the virial de Broglie wavelength is smaller than the size of a dwarf galaxy [26]. The blue region is the constraint derived from looking at neutron EDM oscillation [10]. The green region represents constraints from big bang nucleosynthesis [47], and the yellow region represents constraints from supernova energy loss bounds [48, 49]. The pink region is the constraint described in this work.