We study scatter-like interactions between neutrinos and dark matter in light
of different combinations of temperature, polarization and lensing data
released by three independent CMB experiments - the Planck satellite, the
Atacama Cosmology Telescope (ACT), and the South Pole Telescope (SPT) - in
conjunction with Baryon Acoustic Oscillation (BAO) measurements. We apply two
different statistical methodologies. Alongside the usual marginalization
technique, we cross-check all the results through a Profile Likelihood
analysis. As a first step, working under the assumption of massless neutrinos,
we perform a comprehensive (re-)analysis aimed at assessing the validity of
some recent results hinting at a mild preference for non-vanishing interactions
from small-scale CMB data. We find compelling resilience in the results already
documented in the literature, confirming that interactions with a strength
uνDM∼10−5−10−4 appear to be globally favored by ACT
(both alone and in combination with Planck). This result is corroborated by the
inclusion of additional data, such as the recent ACT-DR6 lensing likelihood, as
well as by the Profile Likelihood analysis. Interestingly, a fully consistent
preference for interactions emerges from SPT, as well, although it is weaker
than the one obtained from ACT. As a second step, we repeat the same analysis
considering neutrinos as massive particles. Despite the larger parameter space,
all the hints pointing towards interactions are confirmed also in this more
realistic case. In addition, we report a very mild preference for interactions
in Planck+BAO alone (not found in the massless case) which aligns with
small-scale data. While this latter result is not fully confirmed by the
Profile Likelihood analysis, the profile distribution does confirm that
interactions are not disfavoured by Planck.Comment: 35 pages, 16 figures, 5 table