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Snowmass2021 Cosmic Frontier White Paper: Ultraheavy particle dark matter
by Daniel Carney, Nirmal Raj, Yang Bai, Joshua Berger, Carlos Blanco, Joseph Bramante, Christopher Cappiello, Maíra Dutra, Reza Ebadi, Kristi Engel, Edward Kolb, J. Patrick Harding, Jason Kumar, Gordan Krnjaic, Rafael F. Lang, Rebecca K. Leane, Benjamin V. Lehmann, Shengchao Li, Andrew J. Long, Gopolang Mohlabeng, Ibles Olcina, Elisa Pueschel, Nicholas L. Rodd, Carsten Rott, Dipan Sengupta, Bibhushan Shakya, Ronald L. Walsworth, Shawn Westerdale
This Submission thread is now published as
Submission summary
| Authors (as registered SciPost users): | Nirmal Raj |
| Submission information | |
|---|---|
| Preprint Link: | https://arxiv.org/abs/2203.06508v2 (pdf) |
| Date accepted: | Oct. 4, 2023 |
| Date submitted: | April 28, 2023, 6:07 a.m. |
| Submitted by: | Raj, Nirmal |
| Submitted to: | SciPost Physics Core |
| Ontological classification | |
|---|---|
| Academic field: | Physics |
| Specialties: |
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| Approaches: | Theoretical, Experimental, Computational, Phenomenological, Observational |
Abstract
We outline the unique opportunities and challenges in the search for "ultraheavy" dark matter candidates with masses between roughly $10~{\rm TeV}$ and the Planck scale $m_{\rm pl} \approx 10^{16}~{\rm TeV}$. This mass range presents a wide and relatively unexplored dark matter parameter space, with a rich space of possible models and cosmic histories. We emphasize that both current detectors and new, targeted search techniques, via both direct and indirect detection, are poised to contribute to searches for ultraheavy particle dark matter in the coming decade. We highlight the need for new developments in this space, including new analyses of current and imminent direct and indirect experiments targeting ultraheavy dark matter and development of new, ultra-sensitive detector technologies like next-generation liquid noble detectors, neutrino experiments, and specialized quantum sensing techniques.
Author comments upon resubmission
List of changes
Dear editor,
We thank the referee for their positive appraisal of our white paper
and recommendation to publish. We also appreciate their valuable comments that we address below.
REFEREE
The detection sections focus on model-independent bounds on heavy dark matter, which looks decoupled from the production mechanism. Some discussion is given in the direct detection section but less in the indirection part. The paper could benefit greatly from more discussions on detecting ultra-heavy dark matter for several mechanisms presented in Sec 2.
OUR RESPONSE
We agree. The DM decay signatures we had discussed are agnostic to the exact cosmological production mechanism so long as particle DM (as opposed to PBHs, etc.) is produced.
Accordingly, we have now added to the introductory paragraph of the indirect detection section the following text.
"Ultraheavy DM models in this category may be generically produced in the early universe by a number of mechanisms discussed above, including freeze-out, freeze-in, gravitational production, and involving phase transitions."
REFEREE
The signatures of heavy dark matter models could also be detected by cosmological observations. The authors may consider adding some discussions on this.
OUR RESPONSE
We appreciate the suggestion. To the end of the indirect detection section we have added the following text.
"Finally, cosmological observations could also constrain ultraheavy DM. CMB anisotropies would carry imprints of DM scattering with SM matter, which may be exploited to probe a wide range of DM masses~cite{Dvorkin:2013cea,Gluscevic:2017ywp,Buen-Abad:2021mvc,Nguyen:2021cnb}. Moreover, ultraheavy DM produced gravitationally is accompanied by primordial non-Gaussianities that may be enhanced and observed in the CMB power spectrum~cite{Li:2019ves,Li:2020xwr}."
REFEREE
For gravitational particle production through inflation, the authors wrote that the production is efficient when dark matter mass is comparable to the inflationary Hubble scale. But I think the production is efficient when the mass is much smaller than the Hubble scale.
OUR RESPONSE
As we had noted, there may be exceptions, however gravitational production as in WIMPzilla models is indeed generically most efficient when the particle mass is comparable to the Hubble scale at the end of inflation. This is stated, e.g., at the end of page 1 in https://arxiv.org/abs/hep-ph/9802238.
With these changes we hope our manuscript will now be taken up for publication.
Published as SciPost Phys. Core 6, 075 (2023)