  Understanding the production mechanism of light (anti)nuclei is one of the
key challenges of nuclear physics and has important consequences for
astrophysics, since it provides an input for indirect dark-matter searches in
space. In this paper, the latest results about the production of light
(anti)nuclei in pp collisions at $\sqrt{s} = 13$ TeV are presented, focusing on
the comparison with the predictions of coalescence and thermal models. For the
first time, the coalescence parameters $B_2$ for deuterons and $B_3$ for
helions are compared with parameter-free theoretical predictions that are
directly constrained by the femtoscopic measurement of the source radius in the
same event class. A fair description of the data with a Gaussian wave function
is observed for both deuteron and helion, supporting the coalescence mechanism
for the production of light (anti)nuclei in pp collisions. This method paves
the way for future investigations of the internal structure of more complex
nuclear clusters, including the hypertriton.
