Peer review of: On quantum gravity tests with composite particles (2020)



RR2
 Reviewers' Comments:
 Reviewer #1:
 Remarks to the Author:
 The authors have addressed all the issues I have raised in my first report and I think that the
 paper has improved in this respect. The approach and in particular the introduction of the
 exponent parameter \alpha remains phenomenological, and deeper arguments on why one should
 adopt such a more general parametrization of the deformation parameter are not provided.
 Despite the significant improvement of the presentation, I still think that the paper should be more
 suitable for a more technical journal.
 Reviewer #2:
 Remarks to the Author:
 The authors have used my feedback and the feedback of other referees
 to significantly improve the manuscript.
 The model remains crude, but it is true that it is an attempt
 to model something that noone else has tried to model and needs
 to be modeled.
 The improvements made to the manuscript are such that now this
 crude model can me more efficiently received by the community.
 In summary I don't think this model will guide the relevant sub-area
 of quantum-gravity phenomenology for long, but it is likely that in
 a few years we will look back at this paper as a paper that played
 a valuable role getting us started in the right direction.
 My personal opinion is that this sort of paper is important and
 benefits particularly from publication in a prestigious journal.
 I therefore recommend publication.
 Reviewer #3:
 Remarks to the Author:
 I think the authors gave very thorough replies to all referees, and while I cannot speak for the
 other referees, the authors did adequately address the points raised in my own review. From my
 point of view, the replies to the other referees' comments are also adequate, and that the
 manuscript benefited from the scrutiny.
 However, upon further review of the manuscript, I gave some more thought to the way the
 authors extracted data from reference 32 of the revised manuscript, and I think the authors should
 address a few points in this respect.
 .) the size of the markers in Fig. 3 of Ref. 32 seem to be much larger than the error stated in that
 reference. In particular, the authors of Ref. 32 stated that the statistical error was $3\times 10^{-
 5}$ seconds. The size of the markers seems to be more on the order of $10^{-4}$ seconds. The
 authors said they zoomed in to extract the data point - probably from the tiny center of the
 markers that can be seen. This is an understandable assumption, but if it is not clearly stated that
 this small dot in the middle is the actual value, the authors may need to assume the full size of the
 markers as the measurement errors. On the other hand, that would slightly over-estimate the
 error provided in the old paper. One would see this if one calculates a reduced $\chi^2$ value for
 the linear fit as I also indicate in my next comment.
 .) comparing Table I of the manuscript with Fig. 3 of Ref. 32, it seems that there are significantly

 more data points in that figure than in the table the authors provide. Did the authors include ALL
 the data points from Fig. 3 of that old paper? I am worried about that because there is of course
 some statistical uncertainty in the data points & not all of them agree with the fit within the errors
 of the measurements. This is as it should be. Statistically speaking only about two thirds of the
 data points should agree with the fit within the error. My worry is that the authors of the present
 manuscript might have extracted a subset of data points that might fit "too well". It would be
 interesting to see a reduce $\chi^2$ value or similar to assess how well (or not) the extracted
 data points agree with the linear fit.
 I think it would be prudent for the authors to address these concerns. Aside from that, I stand by
 my original assessment that I think that the paper in principle deserves publication in Nature
 Communications.