Plots compiling the preliminary and published results on isolated photons $p_{\rm T}$ spectra measured with the photon in EMCal in pp collisions at $\sqrt{s}=$ 7, 8, 13 TeV and p-Pb collisions at $\sqrt{s_{\rm NN}}=$ 5.02 TeV.
Ratios of pp collisions cross sections $\sqrt{s}$ = 13 TeV / $\sqrt{s}$ = 7 TeV, $\sqrt{s}$ = 13 TeV / $\sqrt{s}$ = 8 TeV, $\sqrt{s}$ = 8 TeV / $\sqrt{s}$ = 7 TeV.
All cross sections $p_{\rm T}$ spectra and their ratios 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 p-Pb $\sqrt{s_{\rm NN}}=$ 5.02 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 p-Pb $\sqrt{s_{\rm NN}}$ = 5.02 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, pass1); $p_{\rm T}^{\rm iso,~UE}$ < 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, pass2); $p_{\rm T}^{\rm iso,~ch}$ < 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, pass1); $p_{\rm T}^{\rm iso,~ch,~UE}$ < 1.5 GeV/$c$; Note: https://alice-notes.web.cern.ch/node/849
- p-Pb $\sqrt{s_{\rm NN}}$ = 5.02 TeV: $|\eta|<0.67$ - EMCal (Run 1, 2013, pass3); $p_{\rm T}^{\rm iso,~ch}$ < 1.5 GeV/$c$; Note: https://alice-notes.web.cern.ch/node/1072
