γ -hadron spectra in p + Pb collisions at sNN =5.02 TeV

Abstract

Under the assumption that a quark-gluon plasma (QGP) droplet is produced and its evolution can be described by hydrodynamics in p+A collisions, γ-triggered hadron spectra are studied within a next-to-leading-order perturbative QCD parton model with the medium-modified parton fragmentation functions. The initial conditions and space-time evolution of the small QGP droplet are provided by the superSONIC hydrodynamic model simulations and parton energy loss in such a medium is described by the high-twist (HT) approach. The range of scaled jet transport coefficient q0/T03 in this HT approach is extracted from single hadron suppression in A+A collisions with similar initial medium temperature as in p+A collisions. Numerical results for this scenario show that γ-hadron spectra at pTγ=12-40GeV/c are suppressed by 5-15% in the most central 0-10% p+Pb collisions at sNN=5.02 TeV. The suppression becomes weaker at higher transverse momentum of the γ trigger. As a comparison, γ-hadron suppression in Pb+Pb collisions at sNN=2.76 and 5.02 TeV is also predicted.