l.15: (EM) is the “diphoton” the only “diboson” final state allowed? if other final states like ZZ are possible, you should specify why they are suppressed, similarly to what is written for fermionic final states.

l.25: (EM) all the “scales” in the paper are in GeV/c^2 apart this where they are in TeV

eqs.1, 2, 3: (EM) are these equations really needed? Naively one can interpret them as a toolbox to convert limits on M_S between the different models, but this seems to be not the case if one looks at the values in Table 3, e.g. M_S(GRW) != (pi/2)^(1/4) M_S(Hewett)

l.48-49: (EM) why the threshold of the double-photon trigger is larger than that of the single-photon trigger? If the single-photon is prescaled, you should mention it.

l.65-66: (EM) specify if the “rectangular strip” is centered around the direction of the photon candidate

l.74-82: (EM) difficult to follow what it was done. Also about the optimal choice for |eta|, we found the tone of the explanation too confidential. Perhaps just say that you choose the barrel/endcap boundary and this was driving the M(gamma-gamma)>500 GeV choice. Furthermore in the rest of the paper it is not clear how the intermediate region is used.

l.81-82: (EM) GeV→GeV/c^2 (same in Table 1 headings). BTW: change “500< M_gammagamma GeV” to “M_gammagamma>500 GeV”

l.84: (EM) the scale factor is compatible with one, why is it needed?

l.103: (EM) remove “,” after sample

l.105: (EM) “orthogonal to each other” → “independent”

l.125, 137, 173: (EM) GeV→GeV/c^2

l.142: (EM) Perhaps it is worthwhile to remark that the signal efficiency does not depend on the specific model

eq.4:(EM) what are the coefficients A and B? why are they needed and how the affect the limits on eta_g?

l.145-148: (EM) this discussion seems to be specific to the HLZ description

l.154: (EM) 1/M_S^4 (n=2,95%)=0.078 TeV^-4 → 1/M_S^4=0.078 TeV^-4 95% CL with n_ED=2

Table 2: (EM) These are the systematic uncertainties on what? on the extracted signal cross section S?

Figure 2: (EM) what is the accumulation in the last bin? What are the grey/black bands on top of the MC histo?

Figure 3: (EM) in the caption n→n_ED. In the left pane, why points are alternating above/below the dashed line? Is it because of fluctuations due to the limited MC samples used for the signal?

Table 3: (EM) is there a simple explanation why the HLZ limits are not monotonically decreasing as a function of n_ED?

EM: Ernesto