  The production of prompt $\mathrm {\Lambda_{c}^{+}}$ baryons has been
measured at midrapidity in the transverse momentum interval $0<p_{\rm T}<1$
GeV/$c$ for the first time, in pp and p-Pb collisions at a centre-of-mass
energy per nucleon-nucleon collision $\sqrt{s_\mathrm{NN}} = 5.02$ TeV. The
measurement was performed in the decay channel ${\rm \Lambda_{c}^{+}\to p
K^{0}_{S}}$ by applying new decay reconstruction techniques using a
Kalman-Filter vertexing algorithm and adopting a machine-learning approach for
the candidate selection. The $p_{\rm T}$-integrated $\mathrm {\Lambda_{c}^{+}}$
production cross sections in both collision systems were determined and used
along with the measured yields in Pb-Pb collisions to compute the $p_{\rm
T}$-integrated nuclear modification factors $R_{\rm pPb}$ and $R_\mathrm{AA}$
of $\mathrm{\Lambda_{c}^{+}}$ baryons, which are compared to model calculations
that consider nuclear modification of the parton distribution functions. The
$\mathrm{\Lambda_{c}^{+}/D^0}$ baryon-to-meson yield ratio is reported for pp
and p-Pb collisions. Comparisons with models that include modified
hadronisation processes are presented, and the implications of the results on
the understanding of charm hadronisation in hadronic collisions are discussed.
A significant ($3.7\sigma$) modification of the mean transverse momentum of
$\mathrm {\Lambda_{c}^{+}}$ baryons is seen in p-Pb collisions with respect to
pp collisions, while the $p_{\rm T}$-integrated $\mathrm{\Lambda_{c}^{+}/D^0}$
yield ratio was found to be consistent between the two collision systems within
the uncertainties.
