A Search for Magnetized Quark Nuggets (MQNs), a Candidate for Dark Matter, Accumulating in Iron Ore

Round 1

Reviewer 1 Report

Magnetised Quark Nuggets (MQN) are hypothetical bound, possibly macroscopic, assemblies of large numbers of up, down and strange quarks that have been theoretically suggested as possibly being stable and having properties that may enable them to be candidates for dark matter. The authors reference several theoretical works which describe the stability and existence of such bound states. The existence of MQNs outside the extreme pressure environment of the centres of neutron stars is not entirely convincing and one of the references sited ([5]) says as much. Even if exotic microscopic or macroscopic hadronic matter does exist for a sufficiently long time in isolation, it is not certain that it should be necessarily “dark” and qualify as dark matter. Irrespective of this, the results of searches for MQNs are very important and as such this article should be published provided the experiments are scientifically sound. The idea that they may have accumulated in iron ore is certainly an interesting one and the authors seem to have been thorough in developing models to estimate the expected amount of MQN matter that may have accumulated.
My main concern with the paper was a lack of clarity of presentation. The principle of measurement, the procedure and results could have been presented in a clearer and less ambiguous way. Whilst I recommend publication, I would urge the authors to have second revision with a view to making the experimental procedure and method much clearer. This is particularly important because of the very significant ramifications if it can be demonstrated that significant mass in the form of MQNs is being deposited in the iron ore. 

Author Response

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Thank you for your work reviewing our manuscript and making it a better paper. 

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Reviewer 2 Report

The manuscript entitled "A search for Magnetized Quark Nuggets (MQNs), a candidate for dark matter, accumulating in iron ore" describes as a potential DM baryonic candidate MQNs, and suggest an experiment, giving results, on how to check their presence.

My major concerns are in the following:

- In the simulation the whole halo DM is supposed to be due to MQNs, but this is in contrast with several results, as the bullet cluster measurements, indicating a not-baryonic DM to be dominating

- In plot showing the results, only the error are reported only on one axis, both the errors should be reported in the plots.

- In the text the measurement methods are missing, details on the instrumentation adopted should be given

- In the text no table for comparison of results and expectations are given

- In the summary/conclusion the inconsistency is attributed to the MonteCarlo simulations, if this is the case the paper should be submitted when it will be improved. On the other hand, given the inconsistency, why not report on the basis of model and simulations a confidence region of allowed parameters which could give a consistent result between data and simulations? I suggest the authors to produce some plot similar to confidence regions for WIMP-like DM on the basis of their results.

I suggest to publish the paper only when these points will be addressed, making it more scientific than phenomenological.

nothing to remark

Author Response

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Thank you for your work reviewing our manuscript and making it a better paper. 

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Reviewer 3 Report

Comments for author File: Comments.pdf

Author Response

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Thank you for your work reviewing our manuscript and making it a better paper. 

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Round 2

Reviewer 2 Report

The manuscript entitled "A search for Magnetized Quark Nuggets (MQNs), a candidate for dark matter, accumulating in iron ore" describes as a potential DM baryonic candidate MQNs, and suggest an experiment, giving results, on how to check their presence. The new version is improved in terms of readibility, but still some major has to be addressed.

Major:

1) As still reported in the previous round of review, in the simulation the whole halo DM is supposed to be due to MQNs, but this is in contrast with several results. The authors now explicitally write that MQN are baryonic candidates, but in the text in different points they remark e.g. that MQN can explain the whole DM halo, but this is not true.

Results on the cosmological model or in the search of MACHOS put strong limits to the maximum amount of DM that can be described by baryonic CDM, thus the siulations and the whole paper should be revised in this direction. In particular, the autors replied “Therefore, aggregation is a classical path to stability that may have been missed for decades. Ref. 6 also shows that MQNs meet the weakly interacting requirement of dark matter.” confirming my concerns on this point. Aggregate baryonic DM should be considered as a minor component to the whole DM taking into account baryogenesis and results obtained in microlensing experiments. The new text in lines 46-60 should be revised.

2) In sections Introduction and Appendix A is reported that grad Bz is proportional to m_MQN, I suggest to revise the paper giving an estimate of the mass of the MQN in the different furnaces with uncertainties, then relate it to the DM baryonic density to check how much of the baryonic CDM can be explained by MQN.

3) Line 155 DM halo density should be revised in terms of baryonic DM

4) sentences at lines 271-275 are not scientific sounding, please add a proper refence, i don’t think that writing that some anonymous Inquiry was done is sufficient to justifyy the adopted numbers

5) At lines 380-388 showing a map of the grad Bz measurement is mandatory to show the results and to better explain the method

6) Figure 3 and in the following the y axis means 0% = 0 and 100%=? please clearify

7) About the uncertainties, authors replied “We can assign an uncertainty to the x-axis variable in the original Fig. 3b and have done so, as you noted. The y-axis variable of original Fig. 3a and Fig. 6, and similar plots in the Appendices (which were originally the Supplementary material), is the mathematical
position between 0% and 100% of about 30,000 data points. The uncertainty in any point is +/- 100%/(~30,000), which is much smaller than a line width.” I suggest to them to include this in the paper, but also to explain in detail the +/- 100%/30000 where caomes from. Are the authors for grad Bz using a RMS of all the measured values as an error indicator? I suggest to plot the histogram distribution in one of the measurements of the grad Bz sampling to show that this is a gaussian and RMS or stadard deviation is a good error estimator

8) In lines 565-574 authors suggest some improvement on the Monte Carlo simulations, please extend the discussion and justify why the more realistic MonteCarlo was not used/developed.

9) Lines 926-927 I suggest to extend the discussion about the adopted MonteCarlo

Minor:

- line 69 remove Ga

- line 171 … MQNs form the dark matter ... → … MQNs form part of the dark matter ...

- has MQN interaction with Earth layers/surface some impact on the accumulated MQN?

- revise significant digits in errors and numbers

- line 299 instead of 15% put the numerical value of the error

- B some time has T as units and other times TT, please revise

- in the equations MQN should be always written in capitol letters

The text is well written

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Reviewer 3 Report

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Comments for author File: Comments.pdf

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Round 3

Reviewer 2 Report

Thanks to the authors to have followed my suggestion, I think the manuscript now is strongly improved and it can be published. As a minor I suggest to the authors, if possible, to improve the plots to make them more appealing.