Figure 1

Projected $|{ϵ}_B|$ [left panel] and $|{ϵ}_{B-L}|$ [right panel] sensitivity of various GW facilities/missions as labeled in the legends, assuming that the relevant dark photon is all of the local DM, ${\rho }_{\mathrm{DM}}=0.3{\mathrm{GeV}/\mathrm{cm}}^3$. Mission parameters and sensitivities are given in Table 1. Our main result is the sensitivity of the asteroid-ranging proposal [29], shown (for SNR of 1) as a combination of solid red and dashed orange lines. The solid red part of the curves is for $f\lesssim 1/(5\mathrm{hr})$, where asteroid rotational motion should not be inhibiting; the dashed orange part of the curves is for frequencies where asteroid rotational motion likely severely inhibits that proposal (see discussion in Ref. [29]). The red shaded region of parameter space could thus be accessed with the asteroid-ranging proposal (at SNR of 1), while the orange shaded region could only be accessed if noise issues associated with asteroid rotational motion could be overcome. We also show by the cognate thinner lines the sensitivity projections for a shorter, 4-year mission duration. The sensitivities we show for the LISA mission and the aLIGO facility (for comparative purposes and both also at SNR of 1) are in reasonable agreement with previous analyses [19, 21, 23, 24, 25], up to differences in assumed sensitivities and other mission/facility parameters. Also shown by solid medium-gray and violet lines and shaded regions, respectively, are the 95%-confidence static EP-test constraints (which do not depend on assuming the dark photon is all, or any, of the local dark matter) from the Eöt-Wash experiments [6, 7, 8] and from the final results of the MICROSCOPE mission [13] (recast using the method detailed in Ref. [12]; see discussion in text). The dotted purple line is the cognate limit obtained from the initial MICROSCOPE results [10]; see also Refs. [11, 24]. Recent Eöt-Wash results [labeled ‘Eöt-Wash (2022)’] from Ref. [9] (“field along Z” limits) are shown as light-gray lines, with the thick line representing the approximate exclusion limit averaged over nearby masses, and the limit at any specific mass fluctuating sharply within approximately the envelope denoted by the thin lines.