CMS-PAS-HIN-18-016

CMS-PAS-HIN-18-016
Nuclear modification factor of isolated photons in PbPb collisions at ${\sqrt {\smash [b]{s_{_{\mathrm {NN}}}}}} =$ 5.02 TeV
CMS Collaboration
November 2019

Abstract: The transverse energy ( $E^{\gamma}_\text{T}$ ) spectra and the nuclear modification factors ( $R_{{\mathrm{AA}}}$ ) of isolated photons are analyzed using proton-proton (pp) and lead-lead (PbPb) collisions at ${\sqrt {\smash [b]{s_{_{\mathrm {NN}}}}}} =$ 5.02 TeV. The data were collected using the CMS detector at the CERN LHC with corresponding integrated luminosities of 404 $\mu$ b $^{-1}$ and 27.4 pb $^{-1}$ for PbPb and pp data, respectively. The results are shown as a function of photon $E^{\gamma}_\text{T}$ in the pseudorapidity range $\|{\eta}\| <$ 1.44, for $E^{\gamma}_\text{T}$ between 25 and 200 GeV and for different centrality bins. The data are compared to JEPHOX next-to-leading-order calculations and found to be in good agreement. In addition, $R_{{\mathrm{AA}}}$ is consistent with unity for all centralities in PbPb.
Links: CDS record (PDF) ; inSPIRE record ; CADI line (restricted) ; These preliminary results are superseded in this paper, JHEP 07 (2020) 116. The superseded preliminary plots can be found here.

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