  Nuclear modification factor $R_{AA}(p_{T})$ for large transverse momentum
pion spectra in $Pb+Pb$ collisions at $\sqrt{s}=2.76$ TeV is predicted within
the NLO perturbative QCD parton model. Effect of jet quenching is incorporated
through medium modified fragmentation functions within the higher-twist
approach. The jet transport parameter that controls medium modification is
proportional to the initial parton density and the coefficient is fixed by the
RHIC data on suppression of large $p_{T}$ hadron spectra. Data on charged
hadron multiplicity $dN_{ch}/d\eta=1584 \pm 80$ in central $Pb+Pb$ collisions
from the ALICE Experiment at the LHC are used to constrain the initial parton
density both for determining the jet transport parameter and the 3+1D ideal
hydrodynamic evolution of the bulk matter that is employed for the calculation
of $R_{PbPb}(p_{T})$ for neutral pions.
