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Axion-like particle as Cold Dark Matter via the misalignment mechanism with PQ symmetry unbroken during inflation
by P. Kozow, M. Olechowski
This Submission thread is now published as
Submission summary
| Authors (as registered SciPost users): | Pawel Kozow |
| Submission information | |
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| Preprint Link: | scipost_202210_00016v3 (pdf) |
| Date accepted: | 2023-04-24 |
| Date submitted: | 2022-11-22 18:27 |
| Submitted by: | Kozow, Pawel |
| Submitted to: | SciPost Physics Proceedings |
| Proceedings issue: | 14th International Conference on Identification of Dark Matter (IDM2022) |
| Ontological classification | |
|---|---|
| Academic field: | Physics |
| Specialties: |
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Abstract
The QCD axion and axion-like particles (ALPs) are well motivated candidates for Cold Dark Matter (CDM). Such models may be divided into two classes depending on whether the associated Peccei-Quinn (PQ) symmetry is broken or not during inflation. The latter case is usually considered to be quite simple with relic density depending only on the corresponding decay constant and with no constraints from the known bounds on isocurvature perturbations. We will show that the situation is much more complicated. We will discuss conditions which should be fulfilled by ALP models with U(1) unbroken during inflation to be phenomenologically interesting.
Author comments upon resubmission
We hope that our answers now dispels the referee's doubts.
We list the modifications and answers below.
List of changes
"The authors have answered the questions in the previous report. I really appreciate the texts added to the end of Sec.3, and would happily recommend the publication of this manuscript in SciPost Physics Proceedings, just after the very naive question below.
I still hope to understand Eq. (6) better. In a (post-inflationary) radiation-dominated Universe, the curvature correction should be a function of temperature T, being independent of inflation Hubble parameter HI. So, could the authors explain explicitly why HI appears in the first equality of Eq. (6), but T does not. Is HI simply from Si, and T-terms are negligible, or I am missing something?"
Yes, the dependence in the first equality in eq. (6), on H_I is from S_i .
On one hand, in this work the thermal corrections are assumed absent (according to the already introduced footnote on page 4).
On the other hand, the curvature effects in the post-inflationary universe depend on the temperature only indirectly - they depend on the (changing) Hubble parameter. Then, yes, the corresponding temperature dependence of the first equality in eq. (6) would be very small - hence the approximation sign in the equality.
- The sentence containing eq.(6) was modified accordingly.
"BTW, at the end of footnote 1, it should be "the scope of this work"."
- The typo is now corrected.
Published as SciPost Phys. Proc. 12, 038 (2023)