  Jet quenching has successfully served as a hard probe to study the properties
of Quark-Gluon Plasma (QGP). As a multi-particle system, jets take time to
develop from a highly virtual parton to a group of partons close to mass
shells. In this study, we present a systematical study on the effects of this
formation time on jet quenching in relativistic nuclear collisions. Jets from
initial hard scatterings were simulated with Pythia, and their interactions
with QGP were described using a Linear Boltzmann Transport (LBT) model that
incorporates both elastic and inelastic scatterings between jet partons and the
thermal medium. Three different estimations of the jet formation time were
implemented and compared, including instantaneous formation, formation from
single splitting, and formation from sequential splittings, before which no
jet-medium interaction was assumed. We found that deferring the jet-medium
interaction with a longer formation time not only affects the overall magnitude
of the nuclear modification factor of jets, but also its dependence on the jet
transverse momentum.
