SciPost Submission Page
The Complex Nature of the Abnormally Weak Absorption of Cosmic Ray Hadrons in Lead Calorimeters at Super-High Energies
by Alexander S. Borisov , Evgeniya A. Kanevskaya, Mikhail G. Kogan, Rauf A. Mukhamedshin, Vitalyi S. Puchkov and Shakarmamad G. Yormamadov
Submission summary
| Authors (as registered SciPost users): | Alexander Borisov · Rauf Mukhamedshin |
| Submission information | |
|---|---|
| Preprint Link: | scipost_202411_00064v1 (pdf) |
| Date submitted: | 2024-11-30 21:34 |
| Submitted by: | Mukhamedshin, Rauf |
| Submitted to: | SciPost Physics Proceedings |
| Proceedings issue: | 22nd International Symposium on Very High Energy Cosmic Ray Interactions (ISVHECRI 2024) |
| Ontological classification | |
|---|---|
| Academic field: | Physics |
| Specialties: |
|
| Approach: | Experimental |
Abstract
This paper presents the joint analysis of the results of two similar experiments on the absorption of cosmic ray hadrons using deep lead calorimeters (namely, X-ray emulsion chambers) with large air gap, which were exposed at high altitudes in the Tien Shan and Pamirs mountains. It was found that Monte Carlo simulation of the both experiments allows to reproduce most of specific features of the experimental absorption curve, namely the position, amplitude and width of the peak of electromagnetic origin observed beyond the air gap, assuming that the value of cross section for the production of charm hadrons is as high as σp p→cc¯ s 8 mb at 〈ELab〉 s 75 TeV and at xLab ≳ 0.01. However, we observe at extreme depths of both calorimeters a significant excess of blackening spots (charged particle tracks) compared to the simulations, which cannot be explained by charmed particle production alone. New factors could be carefully considered, such as dark photons, which are currently being searched for by the NA62 collaboration at CERN, or strangelets.
Current status:
Reports on this Submission
Strengths
1 interesting results about absorption of high energy showers in deep absorbers
2 data show sensitivity to charm production
3 the results are essentially clearly presented
Weaknesses
1 claim about dark photons not well supported
2 significance of the unexpected events not well explained
Report
The paper is well written and presents interesting results about charm production in CR induced showers at high altitude. The paper is considered acceptable for publication but requires some minor changes
Requested changes
line 51,52:
it is not understood the sequence of assembly affects the background. Please clarify the sentence
line 54:
find → found
line 60:
"they appeared..." : it is not clear whether this statement refers to FANSY and ECSim or to the other commonly used hadronic interaction models
Figures (quality):
They are compressed pixel files of very poor quality so that the text is hard to read. I strongly suggest to improve their quality to meet the standards of the Journal
Figure 2 and 3(contents):
It is not clear from the caption and text how to read the figures. Are the simulations with 0 and 5 mb scaled upwards for better readability? If not, it should be explained why a smaller charm cross section would lead to a higher number of spots.
line 79:
proved → have been proven
line 110...:
If I understand correclty, it is the shape of the curve in the second part of the calorimeter which matters, not the absolute values. If so, it is not clear to me why 8 mb is so much better than 4 mb. Can this be quantified or an uncertainty be assigned to the best cross section?
line 135-136:
There are data from e.g. the LHC about the charm production cross section.
For example: Eur.Phys.J.Plus 139 (2024) 7, 593 • e-Print: 2311.11426 also giving 8 mb at 5 TeV. A citation would be appropriate.
Figure 4 and discussion in line 137...:
The authors should state how many events are found in the last data points and it should also be stated over which range of depth these points are integrated. This is required before any statement about the significance can be made.
Recommendation
Ask for minor revision
Anonymous on 2025-01-12 [id 5110]
line 51,52:
In my opinion, the text explains quite clearly how the assembly order helps to reduce the background of random spots.
line 54:
agree, "found"
line 60:
Corrected: "namely, they turned out to be too soft compared to both QGSJET II model calculations and the LHC data"
Figures (quality):
We improved the quality of Fig.2 - Fig.4
Figure 2 and 3(contents):
It should be clarified that a significant part of the energy goes into the channel in which charmed particles are born. Accordingly, fewer protons and pions are produced and, as a result, fewer hadron tracks (spots) are formed.
line 79:
Agree, "proven"
line 110 (98)...:
It is not so much the shape that is important as the position of the peak maximum, which shifts to the right as the registration threshold increases (D_min ^1000 = 0.04 provides the best fit). The optimal value for the 8 mb section is determined from Fig.2.
line 135-136 (124):
We have already cited the review of LHC data on charm production and compared it with our results in our previous papers. Due to the limited volume of SciPost publications we omit this topic in the present paper.
Figure 4 and discussion in line 137...:
The number of spots at extreme depths is 186 and 14 spots under 52 and 66 cm of lead for Tien Shan and Pamir, respectively. The number of contributing films is 44 and 11. Another reason of the excess of the absolute number of spots in the layer in Tien Shan chamber compared to that in the Pamir one is the high background of films used in the Pamir experiment compared to the Tien Shan experiment (they were simply considerebly older).
Chamber type// Layer depth (Pb, cm)//Number of spots per layer//Mean number of spots/film//Error
Tien Shan 52 186 4.23 0.31
Simulation 52 - -
Pamir 66 14 1.27 0.38
Simulation 66 - -