  We present exploratory studies of the underlying event activity and of
fragmentation and hadronization of b quarks using $t\overline{t}$ candidate
events in proton-proton collision data acquired by the CMS experiment. We
reconstruct charm mesons in fully charged decay channels from the reconstructed
tracks associated with the hadronization of b quarks from the top decay, and
study their kinematics relative to the mother jet. A good agreement is found
using MadGraph plus the Pythia 6 Tune Z2* simulation. The effects predicted by
alternative settings and generators for the characterization of the underlying
event are also explored. These results are expected to contribute in the future
to more precise measurements in the top quark sector in particular of the top
quark mass by either constraining systematic uncertainties related to the
modeling of the underlying event in $t\overline{t}$ events or by paving the way
for alternative mass measurement methods.
