  In high-energy nuclear collisions the degree of thermalization at the
partonic level is a key issue. Due to their large mass, heavy quarks and their
possible participation in the collective flow of the QCD-medium constitute a
powerful probe for thermalization. We present studies with PYTHIA for p+p
collisions at the top LHC energy of $\sqrt{s}$ = 14 TeV applying the
two-particle transverse momentum correlator $<\Delta p_{t,1}, \Delta p_{t,2}>$
to pairs of heavy-quark hadrons and their semi-leptonic decay products as a
function of their relative azimuth. Modifications or even the complete absence
of initially existing correlations in Pb+Pb collisions might indicate
thermalization at the partonic level.
