Non-standard neutrino cosmology dilutes the lensing anomaly

Understand

Despite the impressive success of the standard cosmological model, several anomalies defy its triumph.

• Among them is the so-called lensing anomaly: the Planck satellite observes stronger CMB gravitational lensing than expected.
• The role of neutrinos in this anomaly has been mostly overlooked, despite their key role in CMB lensing, because in the standard scenario they tend to increase the tension.
• Here, we show that this strongly depends on the assumed neutrino equation of state.