http://arxiv.org/abs/1802.07206
Extensions of the standard models of particle physics and cosmology may lead to the presence of long-range fifth forces whose strength and range depend on gravitational environment. Fifth forces on astrophysical scales are best studied in the cosmic web where perturbation theory breaks down. We present precision constraints on a symmetron- or chameleon-screened fifth force with Yukawa coupling — as well as an unscreened fifth force with differential coupling to galactic mass components — on megaparsec scales by searching for the displacement it predicts between galaxies’ stellar and gas mass centroids. Taking data from the ALFALFA HI survey, identifying galaxies’ gravitational environments with the maps of Desmond et al. (2018) and forward-modelling with a Bayesian likelihood framework, we set upper bounds on the strength of the fifth force relative to Newtonian gravity, $\Delta G/G$, from $\sim 10^{-2}$ ($1\sigma$) for range $\lambda_C = 50$ Mpc to $\sim 10$ for $\lambda_C = 500$ kpc ($f_{R0}<10^{-6}$). The analogous constraints without screening are $\sim 10^{-2}$ and $10^{-1}$. These are the strongest and among the only fifth force constraints on galaxy scales. We show how our results may be strengthened with future survey data and identify the key features of an observational programme for furthering fifth force tests beyond the Solar System.
H. Desmond, P. Ferreira, G. Lavaux, et. al.
Wed, 21 Feb 18
35/58
Comments: 5 pages, 2 figures; PRL submitted