Cosmological constraints on the gravitational interactions of matter and dark matter
Abstract
Although there is overwhelming evidence of dark matter from its gravitational interaction, we still do not know its precise gravitational interaction strength or whether it obeys the equivalence principle. Using the latest available cosmological data and working within the framework of ΛCDM, we first update the measurement of the multiplicative factor of cosmologyrelevant Newton's constant over the standard laboratorybased value and find that it is consistent with one. In general relativity, dark matter equivalence principle breaking can be mimicked by a longrange dark matter force mediated by an ultra light scalar field. Using the Planck three year data, we find that the dark matter ``fifthforce'' strength is constrained to be weaker than 10^{4} of the gravitational force. We also introduce a phenomenological, postNewtonian twofluid description to explicitly break the equivalence principle by introducing a difference between dark matter inertial and gravitational masses. Depending on the decoupling time of the dark matter and ordinary matter fluids, the ratio of the dark matter gravitational mass to inertial mass is constrained to be unity at the 10^{6} level.
 Publication:

Journal of Cosmology and Astroparticle Physics
 Pub Date:
 October 2015
 DOI:
 10.1088/14757516/2015/10/029
 arXiv:
 arXiv:1505.04789
 Bibcode:
 2015JCAP...10..029B
 Keywords:

 High Energy Physics  Phenomenology;
 Astrophysics  Cosmology and Nongalactic Astrophysics
 EPrint:
 doi:10.1088/14757516/2015/10/029