Multiple jets and γ-jet correlation in high-energy heavy-ion collisions

gamma-Jet production is considered one of the best probes of the hot quark-gluon plasma in high-energy heavy-ion collisions since the direct gamma can be used to gauge the initial energy and momentum of the associated jet. This is investigated within the Linear Boltzmann Transport (LBT) model for jet propagation and jet-induced medium excitation. With both parton energy loss and medium response from jet-medium interaction included, LBT can describe experimental data well on gamma-jet correlation in Pb+Pb collisions at the Large Hadron Collider. Multiple jets associated with direct gamma production are found to contribute significantly to gamma-jet correlation at small p(T)(jet) < p(T)(gamma) and large azimuthal angle relative to the opposite direction of gamma.Jet medium interaction not only suppresses the leading jet at large p(T)(jet) but also sub-leading jets at large azimuthal angle. This effectively leads to the narrowing of gamma-jet correlation in azimuthal angle instead of broadening due to jet-medium interaction. The gamma-jet profile on the other hand will be broadened due to jet-medium interaction and jet-induced medium response. Energy flow measurements relative to the direct photon is illustrated to reflect well the broadening and jet-induced medium response. (C) 2018 The Authors. Published by Elsevier B.V.