Spin precession as a new window into disformal scalar fields
Abstract
We launch a first investigation into how a light scalar field coupled both conformally and disformally to matter influences the evolution of spinning point-like bodies. Working directly at the level of the equations of motion, we derive novel spin-orbit and spin-spin effects accurate to leading order in a nonrelativistic and weak-field expansion. Crucially, unlike the spin-independent effects induced by the disformal coupling, which have been shown to vanish in circular binaries due to rotational symmetry, the spin-dependent effects we study here persist even in the limit of zero eccentricity, and so provide a new and qualitatively distinct way of probing these kinds of interactions. To illustrate their potential, we confront our predictions with spin-precession measurements from the Gravity Probe B experiment and find that the resulting constraint improves upon existing bounds from perihelion precession by over 5 orders of magnitude. Our results therefore establish spin effects as a promising window into the disformally coupled dark sector.
Cite
@article{arxiv.2011.01213,
title = {Spin precession as a new window into disformal scalar fields},
author = {Philippe Brax and Anne-Christine Davis and Scott Melville and Leong Khim Wong},
journal= {arXiv preprint arXiv:2011.01213},
year = {2021}
}
Comments
22 pages + an appendix, 3 figures. v2: Version accepted for publication. Typos in Table 1, Eq. (3.21), and Eq. (3.26) have been corrected