Abstract
We investigate constraints on scalar dark matter (DM) by analyzing the Lyman- forest, which probes structure formation at medium and small scales, and also by studying its cosmological consequences at high and low redshift. For scalar DM that constitutes more than 30% of the total DM density, we obtain a lower limit for the mass of scalar DM. This implies an upper limit on the initial field displacement (or the decay constant for an axion-like field) of . We also derive limits on the energy scale of cosmic inflation and establish an upper bound on the tensor-to-scalar ratio of in the presence of scalar DM. Furthermore, we show that there is very little room for ultralight scalar DM to solve the “small-scale crisis” of cold DM without spoiling the Lyman- forest results. The constraints presented in this paper can be used for testing generic theories that contain light scalar fields.
1 More- Received 8 August 2017
DOI:https://doi.org/10.1103/PhysRevD.96.123514
© 2017 American Physical Society