http://cms.cern.ch/cds/TOP-12-006

Marco: General comment on TOP-12-006 The analysis deals with the measurement of the inclusive t-tbar cross section at 7 and 8 TeV c.m.s. energy and their R8/7. The semileptonic channel with an electron or muon and at least 4 jets in the final states defines what is called in the paper the “visible” cross section. This account for about 1.5 - 1.6 % of the total cross section. The measurement of the total inclusive cross-section is obtained with an extrapolation method dividing the Visible cross section by the acceptance deduced with MC First Comment: the extrapolation is very sizeable and totally MC dependent. Many details and arguments are listed in the text and the reader has the impression that the systematics of the measurement are well under control but very few plots to prove it Side general comment: The paper contains only 3 Figures that makes it not easy to read. I would appreciatd more control histograms and pictures especially on the comparison between Data and MC in the “visible” phase space Especially because at the end the measured total inclusive cross sections both at 7 and at 8 TeV are systematically below the theoretical expectations (although in the text is written a questionable “in good agreement”), the same theoretical models that have been used for the extrapolation.

It seems to me that this aspect is not discussed enough and is not convincing