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@article{The:2024:1361-6633/ad4b9b,
author = {The, CMS Collaboration},
doi = {1361-6633/ad4b9b},
journal = {Reports on Progress in Physics},
title = {Extracting the speed of sound in quark–gluon plasma with ultrarelativistic lead–lead collisions at the LHC},
url = {http://dx.doi.org/10.1088/1361-6633/ad4b9b},
volume = {87},
year = {2024}
}
TY - JOUR
AB - Ultrarelativistic nuclear collisions create a strongly interacting state of hot and dense quark–gluon matter that exhibits a remarkable collective flow behavior with minimal viscous dissipation. To gain deeper insights into its intrinsic nature and fundamental degrees of freedom, we determine the speed of sound in an extended volume of quark–gluon plasma using lead–lead (PbPb) collisions at a center-of-mass energy per nucleon pair of 5.02 TeV. The data were recorded by the CMS experiment at the CERN LHC and correspond to an integrated luminosity of 0.607 nb−1. The measurement is performed by studying the multiplicity dependence of the average transverse momentum of charged particles emitted in head-on PbPb collisions. Our findings reveal that the speed of sound in this matter is nearly half the speed of light, with a squared value of 0.241 ± 0.002 (stat) ± 0.016 (syst) in natural units. The effective medium temperature, estimated using the mean transverse momentum, is 219 ± 8 (syst) MEV. The measured squared speed of sound at this temperature aligns precisely with predictions from lattice quantum chromodynamic (QCD) calculations. This result provides a stringent constraint on the equation of state of the created medium and direct evidence for a deconfined QCD phase being attained in relativistic nuclear collisions.
AU - The,CMS Collaboration
DO - 1361-6633/ad4b9b
PY - 2024///
SN - 0034-4885
TI - Extracting the speed of sound in quark–gluon plasma with ultrarelativistic lead–lead collisions at the LHC
T2 - Reports on Progress in Physics
UR - http://dx.doi.org/10.1088/1361-6633/ad4b9b
UR - https://doi.org/10.1088/1361-6633/ad4b9b
UR - http://hdl.handle.net/10044/1/116435
VL - 87
ER -