Gravitational waves in Einstein–Cartan theory: On the effects of dark matter spin tensor

This article studies the effects of an arbitrary dark matter spin tensor on propagation gravitational wave amplitude in context Einstein–Cartan theory. We choose to work with because, given our ignorance nature matter, it is sensible not make further hypotheses its and assume any particular model for (or vanishing). The analysis focuses a “weak-torsion regime”, such that emission, at leading subleading orders, does deviate from standard General Relativity. show that, principle, background torsion induced by eventual component could lead anomalous dampening or amplification amplitude, after going across long cosmological distance. assess importance this torsion-induced binary black hole mergers way as model-free possible gravity. It prove best, realistic late-universe scenarios, effect tiny falls below detection thresholds, even near-future interferometers LISA. Therefore, detecting may be impossible, but still beyond technological capabilities. As model-independent result context, also implies are robust sirens without considering potential dark-matter-induced torsional effects.