Kaon Femtoscopy with Lévy-Stable Sources from
Round 1
Reviewer 1 Report
This paper summarizes Femtoscopy in high-energy heavy-ion collisions and presents new data from the STAR experiment on the like-sign kaon-pairs.
I have the following questions and comments that should be addressed before publication.
1. It would be helpful to provide an explanation in the introduction regarding why like-sign kaon-pairs shed light on the origin of non-Gaussianity.
2. It is necessary to define the quantity X in Eq.(6). Is it X=X_1 - X_2?
3. Eq.(4) cannot be the same as Eq.(8).
There seems to be a discrepancy between Eq.(4) and Eq.(8). In Eq.(8), \tilde{S} should be \tilde{S}_C, and it would be necessary to clarify the assumption of S_H=0 to obtain Eq.(8). Please provide justification for assuming S_H=0.
4. It is hard to understand Eq.(13) from the reference [26]. Can you add other
references?
5. Please add the references for lines 206-207.
6. In lines 215-216, it is mentioned that 'the small fraction of decay-kaons'
is considered. However, kaons can come from the decays of the nucleon (N*) and delta resonances
(Delta*) as well as kaon resonances (K*). It is expected that a large number of those resonances
exist at the late hadronic resonance stage.
Author Response
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The paper discusses Kaon femtoscopy with Lévy-stable sources, and is useful for the community. I recommend this paper to be published in Universe.
Author Response
I would like to express my gratitude to the referee for reviewing my submission and recommending it for publication.
Reviewer 3 Report
General comments
The manuscript starts with an introduction to the femtoscopy as a method to probe characteristics of a particle emission source in heavy-ions collisions. The concept of two-particle correlation function is introduced for a non-Gaussian source described by a Levy-stable distribution function. This function is used to fit preliminary STAR data for K+K+ and K-K- pairs collected for Au-Au collisions at $\sqrt{s_{NN}}=200$ GeV. The parameters $R$, $\lambda$ and $\alpha$ of Levy distribution were extracted separately for K+K+ and K-K- pairs demonstrating the deviation of the resulting correlation function from Gaussian. This indicates the existence of an anomalous diffusion process in emission of kaons from hot and dense nuclear matter created in heavy-ion collisions. The methodology used by the author is solid and a general message of this study is clearly formulated.
I recommend the paper for publication after introducing few changes suggested below. While the text is written well in general, an excessive use of semicolons makes difficult to read and understand some sentences. As known, the semicolon is one of the least understood of the punctuation marks, and so it is not as frequently used by most of English speakers. I would suggest to reformulate the sentences where more than two semicolons are used for a more plain style of writing.
Specific comments
L21-22: "Earlier, hydrodynamical, studies undertaken seemed to suggest that the source-shape looked Gaussian [3,6]."
Remove "that" and try to rewrite this sentence for clarity.
L25-27: "Since the measurements of lengths and time-intervals; required to determine the source-shape; needed to be done on the femtometre (fm) scale, a sub-field of high-energy heavy-ions physics needed to be dedicated to the effort."
It seems that this sentence is not necessary because almost the same meaning is expressed in the next quite succinct statement (L27-29).
L29-32 seem to be misleading, as one may understood that as the femtoscopic correlations were invented by Hanbury-Brown and Twiss.
Instead, it is better to write something like that:
"Femtoscopic correlations in heavy-ion collisions are currently understood to be caused partly by Bose Einstein statistics [19–22]. Alternatively they are called Hanbury-Brown-Twiss (HBT) correlations in recognition of pioneering works by Hanbury-Brown and Twiss [16–18] on intensity interferometry in the field of observational astronomy to extract the apparent angular sizes of stars from correlations between the signals of two detectors."
L127: "... with the terms explained in Ref.[36]"
It would be better to define these terms, $\alpha\prime$, $L_{FP}$ etc. also here.
Figure 1: It is recommended to adhere to the standard style of figure captions with placement of (a) and (b) on the left and right panels and their full explanation in the extended figure caption.
L133: This is the right place to give physical meaning of $R$ and $\alpha$, not just their formal mathematical definitions given above.
While the text is written well in general, an excessive use of semicolons makes difficult to read and understand some sentences. As known, the semicolon is one of the least understood of the punctuation marks, and so it is not as frequently used by most of English speakers. I would suggest to reformulate the sentences where more than two semicolons are used for a more plain style of writing.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
I am still confused by Eq.(9), which I think is wrong. I have attached my note (pdf file) to explain why I think it is wrong. I would appreciate it if you look at my note and mention whether it is correct.
Comments for author File: Comments.pdf
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 3 Report
The author successfully implemented the proposed changes and updates. Due to several simplifications of the wording, the new version of the text is easy to read. I believe that the manuscript can be accepted in its present form.
Author Response
I would like to thank the referee for proposing the changes and updates to the manuscript. They have served, in my opinion, to make it better.
I am grateful to the referee for bettering my manuscript and recommending it, in its current form, for publication.
Round 3
Reviewer 1 Report
I would like to accept this manuscript in the journal of universe.
