Measurement of isolated-prompt photon−hadron correlations in Pb−Pb collisions at √(sNN) = 5.02 TeV
Abstract
The ALICE Collaboration has measured the azimuthal correlation between trigger isolated-prompt photons and associated charged hadrons in Pb−Pb collisions at the CERN LHC, at a centre-of-mass energy per nucleon pair of √(sNN) = 5.02 TeV. The trigger isolated-prompt photons are measured in the transverse-momentum range 18<pTγ<40 GeV/c and pseudorapidity range |ηγ| <0.67. The isolation selection is based on a charged particle isolation momentum threshold pTiso, ch = 1.5 GeV/c within a cone of radius R=0.2. The yield D(zT) of associated hadrons per trigger, with zT = pTh/pTγ, is measured in three Pb−Pb collision centrality classes: central (0−30%), semicentral (30−50%), and peripheral (50−90%). An approximation to the standard IAA is computed from the D(zT) conditional yields, using NLO pQCD predictions as pp reference, the IpQCD. A strong suppression of this ratio is observed in central collisions compared to peripheral collisions. The result extends to a lower pTγ relative to those reported in previously published Pb−Pb collisions measurements at √(sNN) = 5.02 TeV. The IpQCD measurement is compared to IAA calculations with an NLO pQCD model that includes energy loss, and to the CoLBT-hydro model. The IpQCD results from central collisions are also compared with IAA measurements of jets correlated with isolated-prompt photons and of hadrons correlated with Z0 bosons, both reported by the CMS Collaboration at the LHC, as well as with direct photon−hadron correlation IAA measurements reported by the PHENIX and STAR Collaborations at RHIC.
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BibTeX
@misc{collaboration2026measurement,
title = {{Measurement of isolated-prompt photon$-$hadron correlations in Pb$-$Pb collisions at $\mathbf\sqrt\textits_\rm NN = 5.02$ TeV}},
author = {ALICE Collaboration},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2605.02342},
eprint = {2605.02342},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2605.02342},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Measurement of isolated-prompt photon−hadron correlations in Pb−Pb collisions at √(s_NN) = 5.02 TeV
AU - ALICE Collaboration
PY - 2026
DA - 2026/09/28
PB - arXiv
DO - 10.48550/arxiv.2605.02342
UR - https://arxiv.org/abs/2605.02342
AB - The ALICE Collaboration has measured the azimuthal correlation between trigger isolated-prompt photons and associated charged hadrons in Pb−Pb collisions at the CERN LHC, at a centre-of-mass energy per nucleon pair of √(s_NN) = 5.02 TeV. The trigger isolated-prompt photons are measured in the transverse-momentum range 18<p_T^γ<40 GeV/c and pseudorapidity range |η^γ| <0.67. The isolation selection is based on a charged particle isolation momentum threshold p_T^iso, ch = 1.5 GeV/c within a cone of radius R=0.2. The yield D(z_T) of associated hadrons per trigger, with z_T = p_T^h/p_T^γ, is measured in three Pb−Pb collision centrality classes: central (0−30%), semicentral (30−50%), and peripheral (50−90%). An approximation to the standard I_AA is computed from the D(z_T) conditional yields, using NLO pQCD predictions as pp reference, the I_pQCD. A strong suppression of this ratio is observed in central collisions compared to peripheral collisions. The result extends to a lower p_T^γ relative to those reported in previously published Pb−Pb collisions measurements at √(s_NN) = 5.02 TeV. The I_pQCD measurement is compared to I_AA calculations with an NLO pQCD model that includes energy loss, and to the CoLBT-hydro model. The I_pQCD results from central collisions are also compared with I_AA measurements of jets correlated with isolated-prompt photons and of hadrons correlated with Z^0 bosons, both reported by the CMS Collaboration at the LHC, as well as with direct photon−hadron correlation I_AA measurements reported by the PHENIX and STAR Collaborations at RHIC.
ER -