  We investigate top anti-top quark pair production in lead-lead collisions at
the Large Hadron Collider with nucleon-nucleon center of mass energy of 5.5
TeV. Due to the very high temperature and energy density created in heavy ion
collision, a new state of QCD matter known as Quark-Gluon Plasma (QGP) is
expected to be produced. Top decay products loose energy inside the QGP medium.
Therefore, we also study the medium modifications of different kinematic
distributions. We observe significant modification in the dijets and trijets
invariant mass distributions.We also found that the peak position and shape of
the distributions could be used to characterize the nature of jet energy loss
in the QGP.
