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| Main Authors: | , , |
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| Format: | Preprint |
| Published: |
2024
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2405.10367 |
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| _version_ | 1866914011769995264 |
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| author | García-Cely, Camilo Landini, Giacomo Zapata, Óscar |
| author_facet | García-Cely, Camilo Landini, Giacomo Zapata, Óscar |
| contents | QCD-like theories in which the dark matter (DM) of the Universe is hypothesized to be a thermal relic in the form of a dark pion has been extensively investigated, with most studies neglecting the CP-violating $θ$-angle associated with the topological vacuum. We point out that a non-vanishing $θ$ could potentially trigger resonant number-changing processes giving rise to the observed relic density in agreement with perturbative unitarity as well as observations of clusters of galaxies. This constitutes a novel production mechanism of MeV DM and an alternative to those relying on the Wess-Zumino-Witten term. Moreover, for specific meson mass spectra, similar resonant scatterings serve as a realization of velocity-dependent self-interacting DM without a light mediator. Explicit benchmark models are presented together with a discussion of possible signals, including gravitational waves from the chiral phase transition associated with the dark pions. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2405_10367 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Dark matter in QCD-like theories with a theta vacuum: cosmological and astrophysical implications García-Cely, Camilo Landini, Giacomo Zapata, Óscar High Energy Physics - Phenomenology QCD-like theories in which the dark matter (DM) of the Universe is hypothesized to be a thermal relic in the form of a dark pion has been extensively investigated, with most studies neglecting the CP-violating $θ$-angle associated with the topological vacuum. We point out that a non-vanishing $θ$ could potentially trigger resonant number-changing processes giving rise to the observed relic density in agreement with perturbative unitarity as well as observations of clusters of galaxies. This constitutes a novel production mechanism of MeV DM and an alternative to those relying on the Wess-Zumino-Witten term. Moreover, for specific meson mass spectra, similar resonant scatterings serve as a realization of velocity-dependent self-interacting DM without a light mediator. Explicit benchmark models are presented together with a discussion of possible signals, including gravitational waves from the chiral phase transition associated with the dark pions. |
| title | Dark matter in QCD-like theories with a theta vacuum: cosmological and astrophysical implications |
| topic | High Energy Physics - Phenomenology |
| url | https://arxiv.org/abs/2405.10367 |