Addendum: Refined bounds on MeV-scale thermal dark sectors from BBN and
  the CMB
  Very recently, the LUNA collaboration has reported a new measurement of the
$d+p\to {}^{3}\text{He}+\gamma$ reaction rate, which plays an important role in
the prediction of the primordial deuterium abundance at the time of BBN. This
new measurement has triggered a new set of global BBN analyses within the
context of the Standard Model. In this addendum to JCAP 01 (2020) 004
(arXiv:1910.01649), we consider the implications of these new results for our
constraints on MeV-scale dark sectors. Importantly, we find that our bounds in
the BBN-only and Planck-only analyses are insensitive to these updates.
Similarly, we find that our constraints derived using BBN and CMB data
simultaneously are not significantly modified for neutrinophilic particles. The
bounds on electrophilic dark sector states, however, can vary moderately when
combining BBN and CMB observations. We present updated results for all the
relevant light dark sector states, calculated using the rates obtained by the
leading groups performing standard BBN analyses.
