Plots compiling the preliminary and published results on isolated photons $p_{\rm T}$ spectra measured with the photon EMCal in pp collisions at $\sqrt{s}=$ 7, 8, 13 TeV.
All cross sections $p_{\rm T}$ spectra are shown for ALICE measurement and NLO JETPHOX calculation with NNPDOF40, NLO calculations scaled down by the partonic to hadronic isolation efficiency $\kappa^{\rm iso}$.
Isolation energy ($p_{\rm T}^{\rm iso}$) change from isolation using only charged particles ($p_{\rm T}^{\rm iso,~ch}$ , pp $\sqrt{s}=$ 8, 13 TeV) and using neutral (calorimeter) and charged particle information (pp $\sqrt{s}=$ 7 TeV), and subtracting the underlying event from the isolation energy (pp $\sqrt{s}$ = 8 TeV) and not subtracting it ($p_{\rm T}^{\rm iso,~UE}$, pp $\sqrt{s}=$ 7, 13 TeV). Cone size is $R=0.4$ common to all systems.
Acceptance considered is also different depending the system, summary of differences between systems:
- pp $\sqrt{s}$ = 7 TeV: $|\eta|<0.27$ - EMCal only (Run 1, 2011); $p_{\rm T}^{\rm iso,~UE}$ < 2 GeV/$c$; Paper: https://alice-publications.web.cern.ch/node/5092
- pp $\sqrt{s}$ = 8 TeV: $|\eta|<0.52$ - EMCal only (Run 1, 2012); $p_{\rm T}^{\rm iso,~ch}$ < 1.5 GeV/$c$; Note: https://alice-notes.web.cern.ch/node/1254
- pp $\sqrt{s}$ = 13 TeV: $|\eta|<0.67$ - EMCal and DCal (Run 2, 2016, 2017, 2018); $p_{\rm T}^{\rm iso,~ch,~UE}$ < 1.5 GeV/$c$; Note: https://alice-notes.web.cern.ch/node/849