PeV-Scale SUSY and Cosmic Strings from F-Term Hybrid Inflation

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The manuscript presents an intricate analysis of F-term hybrid inflation (FHI) and SUSY breaking within the context of a B − L extension of MSSM, with emphasis on preserving a global U(1) R symmetry. The study explores the hidden sector Kaehler manifold's enhanced SU(1, 1)/U(1) symmetry, aiming to achieve a SUSY-breaking de Sitter vacuum without extensive tuning. Notably, FHI is found to be consistent with data, with the emergence of B − L cosmic strings being observed if metastable. The implementation of FHI alongside SUSY breaking and cosmic string formation in a B-L extension of MSSM is meticulously analyzed, offering several significant achievements. These include an observationally acceptable FHI of hilltop-type, a prediction for the SUSY-mass scale, an interpretation of the dark energy problem without extensive tuning, and explanations for the µ term of MSSM. However, potential shortcomings are acknowledged, such as the challenge of baryogenesis due to the low reheat temperature, which may require extensions of MSSM or alternative mechanisms. Additionally, further investigation is warranted regarding the candidacy of the lightest neutralino as dark matter, and the stability of the R axion. The manuscript provides a comprehensive overview of the proposed scenario and offers intriguing insights into addressing naturalness issues within the context of SUSY. Overall, the study contributes significantly to the understanding of inflationary models and SUSY-breaking mechanisms, warranting consideration for publication here.

Author Response

I would like to cordially thank the reviewer 1 for his positive consideration

Reviewer 2 Report

Comments and Suggestions for Authors

The author is presenting a model based on a B-L extension of the MSSM with a globally U(1) R symmetry (mostly invariant under thisR symmetry). The model is interesting but in the analysis, the effects of each terms of the Kahler potential or the Superpotential are treated as separated just to solve observational aspects of cosmology and the crossed effects are not taken into account. These crossed effects could significantly change the results of the model.  

I have also some generic comments on the text: 

1. the use of abbreviation should be well defined and using the same type of letter than  the ones used in the paper (see for instance the abbreviations introduced  from line 28 to 38 and later used in the paper). This problem of abbreviation is making difficult to read the presentation of the model and the discussions of the results.  

2. IS and HS in line 117 should be defined. 

3. in KH, they assumed a term which is violating the R symmetry, generating accepting mass for a R axion. This point should be explained with more details and why not to include other terms which could break R symmetry. 

4. the model has much more free parameters than the 7 cited in line 281.

 

In conclusion, I don't recommend to accept this paper in the form it is written but could be submitted later after substancial changes. 

Best regards

Author Response

My reply is written in the file

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

In this paper, the breaking of supersymmetry at PeV scale and the generation of cosmic strings are studied in F-term hybrid inflation for the case of B-L extension of minimal supersymmetric standard model with a global U(1) R symmetry. The manuscript is given in detail. If the following points are investigated then the revised manuscript could be re-considered for publication.

1) In comparison with past similar works on the breaking of supersymmetry and the resultant generation of cosmic strings in inflationary cosmology, the originality and significant results different from the past reported ones would be explained, so that the significance to describe this article can be clarified.

2) An enhanced SU(1, 1)/U(1) symmetry with the scalar curvature is naturally realized in F-term hybrid inflation. What are the new physics mechanisms (compared with the past inflationary models) yielding the inflation consistent with the recent observational results including the Planck 2018?

3) Through the PeV scale SUSY breaking, the B-L cosmic strings are generated. There exist many past works on the generation of cosmic strings. What are the novel scenario and methods for analysis?
 
4) By the Giudice-Masiero mechanism, the out-of-equilibrium decay of the R saxion is realized, so that the gravitational wave signal can be suppressed at high frequencies. From these consequences, what fundamental and the eary universe physics can be understood?

Author Response

My reply is included in the file

Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

Comments and Suggestions for Authors

The authors' answers and revision are highly appreciated.
The points in the review report have been explained.
The revised manuscript thus could be suitable for publication.