Pseudoscalar - sterile neutrino interactions: reconciling the cosmos
  with neutrino oscillations
  The Short BaseLine (SBL) neutrino oscillation anomalies hint at the presence
of a sterile neutrino with a mass of around 1 eV. However, such a neutrino is
incompatible with cosmological data, in particular observations of the Cosmic
Microwave Background (CMB) anisotropies. However, this conclusion can change by
invoking new physics. One possibility is to introduce a secret interaction in
the sterile neutrino sector mediated by a light pseudoscalar. In this
pseudoscalar model, CMB data prefer a sterile neutrino mass that is fully
compatible with the mass ranges suggested by SBL anomalies. In addition, this
model predicts a value of the Hubble parameter which is completely consistent
with local measurements.
