Quantifying the global parameter tensions between ACT, SPT, and <i>Planck</i>
Will Handley, Pablo Lemos
Abstract
The overall cosmological parameter tension between the Atacama Cosmology Telescope 2020 fourth data release (ACT) and Planck 2018 data within the concordance cosmological model is quantified using the Suspiciousness statistic to be $2.6\ensuremath{\sigma}$. Between ACT and the South Pole Telescope (SPT) we find a tension of $2.4\ensuremath{\sigma}$, and $2.8\ensuremath{\sigma}$ between ACT and $\mathrm{Planck}+\mathrm{SPT}$ combined. While it is unclear whether the tension is caused by statistical fluctuations, systematic effects or new physics, caution should be exercised in combining these cosmic microwave background datasets in the context of the $\mathrm{\ensuremath{\Lambda}}\mathrm{CDM}$ standard model of the universe.