  Relativistic heavy-ion experiments have observed similar quenching effects
for (prompt) $D$ mesons compared to charged hadrons for transverse momenta
larger than 6-8~GeV, which remains a mystery since heavy quarks typically lose
less energies in quark-gluon plasma than light quarks and gluons. Recent
measurements of the nuclear modification factors of $B$ mesons and $B$-decayed
$D$ mesons by the CMS Collaboration provide a unique opportunity to study the
flavor hierarchy of jet quenching. Using a linear Boltzmann transport model
combined with hydrodynamics simulation, we study the energy loss and nuclear
modification for heavy and light flavor jets in high-energy nuclear collisions.
By consistently taking into account both quark and gluon contributions to light
and heavy flavor hadron productions within a next-to-leading order perturbative
QCD framework, we obtain, for the first time, a satisfactory description of the
experimental data on the nuclear modification factors for charged hadrons, $D$
mesons, $B$ mesons and $B$-decayed $D$ mesons simultaneously over a wide range
of transverse momenta (8-300~GeV). This presents a solid solution to the flavor
puzzle of jet quenching and constitutes a significant step towards the
precision study of jet-medium interaction. Our study predicts that at
transverse momenta larger than 30-40~GeV, $B$ mesons also exhibit similar
suppression effects to charged hadrons and $D$ mesons, which may be tested by
future measurements.
