Hidden-sector modifications to gravitational waves from binary inspirals

Abstract

Gravitational wave astronomy has placed strong constraints on fundamental physics, and there is every expectation that future observations will continue to do so. In this work we quantify this expectation for future binary merger observations to constrain hidden sectors, such as scalar-tensor gravity or dark matter, which induce a Yukawa-type modification to the gravitational potential. We explicitly compute the gravitational waveform, and perform a Fisher information matrix analysis to estimate the sensitivity of next generation gravitational wave detectors to these modifications. We find an optimal sensitivity to the Yukawa interaction strength of 10 −5 and to the associated dipole emission parameter of 10 −7 , with the best constraints arising from the Einstein Telescope. When applied to a minimal model of dark matter, this provides an exquisite probe of dark matter accumulation by neutron stars, and for sub-TeV dark matter gravitational waves are able to detect mass fractions mDM /mNS less then 1 part in 10 15 .

New probe of dark matter-induced fifth force with neutron star inspirals

“…Our method applied to ET yields similar or actually slightly worse sensitivity than the more dedicated estimation in Ref [22]3.…”

“…A light scalar (again not necessarily the main DM) can also be efficiently radiated if each NS carries different scalar charge-to-mass ratio, forming a scalar-charge dipole [7,20]. This dipole radiation is qualitatively different from the GW quadrupole radiation, thus can be tested with GW waveform evolution [20][21][22]. It is efficient for any light scalars with long enough Compton wavelength 1/m φ 10 km.…”

Polarization modes of gravitational waves in quadratic gravity

“…In dCS and EdGB gravity, as well as probably in other theories of gravity, the polarization content of GWs remains the same as in GR, and thus, polarization tests of GR with GWs are uninformative. The best avenue to constrain these theories, therefore, continues to be the dynamical late inspiral and merger phase of coalescing binaries [44].…”

Science case for the Einstein telescope

“…The presence of a dark matter core in a neutron star might again have an imprint upon the GW signal during binary inspiral and merger. Dark matter accumulating in neutron stars and interacting through Yukawa-like interactions in the dark sector could affect the orbital dynamics of a neutron star binaries, and therefore the corresponding waveform, in a way detectable by ET [174], whose low-frequency sensitivity makes it an especially sensitive probe to dark matter mediated forces between neutron stars. In some models [175,176], the accumulation of dark matter may lead to the formation of a black hole inside a neutron star, which then accretes the remaining neutron star matter, leading to black holes of (1 − 2) M that could be observed by ET.…”