  The James Webb Space Telescope (JWST) observations have been demonstrated to
be efficient in detecting globular clusters' (GCs) multiple stellar populations
in the low mass regime of M dwarfs. We present an overview, and first results,
of different projects that can be explored by using the JWST observations
gathered under the GO2560 for 47 Tucanae, a first program entirely devoted to
the investigation of multiple populations in very low mass stars, which
includes spectroscopic data for the faintest GC stars for which spectra are
available. Our color-magnitude diagram (CMD) shows some substructures for
ultracool stars, including gaps and breaks in slope. In particular, we observe
both a gap and a minimum in the F322W2 luminosity function less than one
magnitude apart, and discuss which one could be associated with the H-burning
limit. We detect stars fainter than this minimum, very likely the brown dwarfs.
We corroborate the ubiquity of the multiple populations across different
masses, from ~0.1 solar masses up to red giants (~0.8 solar masses). The oxygen
range inferred from the M dwarfs, both from the CMD and from the spectra of two
M dwarfs associated with different populations, is similar to that observed in
giants. We have not detected any difference between the fractions of stars in
distinct populations across stellar masses >~0.1 solar masses. This work
demonstrates the JWST's capability in uncovering multiple populations within M
dwarfs and illustrates the possibility to analyse very low-mass stars in GCs
approaching the H-burning limit and the brown-dwarf sequence.
