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Dark matter from the centre of SU (N )
by Michele Frigerio, Nicolas Grimbaum-Yamamoto, Thomas Hambye
This Submission thread is now published as
Submission summary
| Authors (as registered SciPost users): | Michele Frigerio · Nicolas Grimbaum-Yamamoto |
| Submission information | |
|---|---|
| Preprint Link: | scipost_202302_00014v2 (pdf) |
| Date accepted: | 2023-06-06 |
| Date submitted: | 2023-04-12 10:56 |
| Submitted by: | Frigerio, Michele |
| Submitted to: | SciPost Physics |
| Ontological classification | |
|---|---|
| Academic field: | Physics |
| Specialties: |
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| Approaches: | Theoretical, Phenomenological |
Abstract
A dark sector with non-abelian gauge symmetry provides a sound framework to justify stable dark matter (DM) candidates. We consider scalar fields charged under a $SU(N)$ gauge group, and show that the centre of $SU(N)$, the discrete subgroup $Z_N$ also known as $N$-ality, can ensure the stability of scalar DM particles. We analyse in some details two minimal DM models of this class, based on $SU(2)$ and $SU(3)$, respectively. These models have non-trivial patterns of spontaneous symmetry breaking, leading to distinctive phenomenological implications. For the $SU(2)$ model these include a specific interplay of two DM states, with the same interactions but different masses, and several complementary DM annihilation regimes, either within the dark sector or through the Higgs portal. The $SU(3)$ model predicts dark radiation made of a pair of dark photons with a unique gauge coupling, as well as regimes where DM semi-annihilations become dominant and testable.
Author comments upon resubmission
Here is our answer to the Referees and the corresponding changes to the manuscript:
Report 1:
We thank the Referee for useful comments, and we addressed the various points raised as follows:
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We added the required sentence at the very beginning of section 5.
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Concerning the ellipticity constraint, in the last paragraph of section 5.2.1 we added a couple of sentences to explain better how this constraint is obtained. We provide appropriate references for the Readers interested into a more technical discussion.
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We agree with the Referee that it would be useful to derive such constraints, but we are not aware of any dedicated study at the moment, which could allow to specify quantitatively which part of the left panel of Figure 6 could be probed by neutrino telescope searches for a boosted DM flux. A few lines below eq. 47 we added a sentence to say this explicitly.
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At the end of section 5.2.3 we added a few sentences to state explicitly that the next generation of direct detection experiments will be able to exclude the allowed regions in figure 5.
Report 2:
We thank the Referee for useful comments and pointing out relevant references in his report. Here are our answers to the specific points raised:
1&2. In this paper, we decided to specifically address DM that is stabilised by gauge symmetries only. In the introduction we review the literature specific to this type of mechanism, so we do not discuss stabilisation through global symmetries. We amended our references according to the suggestions of the Referee.
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We added the citation to the paragraph discussing monopole DM as requested.
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Models with SU(N) gauge symmetry with N>3 are problematic, as we already stated in section 2. In addition, to determine the symmetry breaking pattern would require an involved study of the properties of the potential for each case. The large scale structure constraints mentioned by the Referee are tricky and do not apply to our models with N=2,3, therefore we prefer not to enter into this discussion in this paper.
List of changes
See our answer to the Referees.
Published as SciPost Phys. 15, 177 (2023)