How an era of kination impacts substructure and the dark matter annihilation rate

Délos, Marc; Redmond, Kayla; Erickcek, Adrienne L.

doi:10.1103/physrevd.108.023528

Cited by 3 publications

(1 citation statement)

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“…Unlike previous approaches based on subhalo modeling, the prompt cusp paradigm enables straightforward evaluation of the annihilation rate for alternative initial conditions of this kind (e.g. [64,65]).…”

Section: Discussionmentioning

confidence: 99%

Prompt cusps and the dark matter annihilation signal

Delos,

White

2023

J. Cosmol. Astropart. Phys.

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As the first dark matter objects gravitationally condense, a density cusp forms immediately at every initial density maximum. Numerical simulations and theoretical arguments suggest that these prompt cusps can survive until the present day. We show that if dark matter is a thermally produced weakly interacting massive particle, many thousands of prompt cusps with individual masses similar to that of the Earth may be present in every solar mass of dark matter. This radically alters predictions for the amount and spatial distribution of dark matter annihilation radiation. The annihilation rate is boosted by at least an order of magnitude compared to previous predictions, both in the cosmological average and within galaxy-scale halos. Moreover, the signal is predominantly boosted outside of the centers of galactic halos, so alternative targets become significantly more attractive for indirect-detection searches. For example, prompt cusps present new opportunities to test the dark matter interpretation of the Galactic Center γ-ray excess by searching for similar spectral signatures in the isotropic γ-ray background and large-scale cosmic structure.

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Section: Discussionmentioning

confidence: 99%

Prompt cusps and the dark matter annihilation signal

Delos,

White

2023

J. Cosmol. Astropart. Phys.

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String theory and the first half of the universe

Apers,

Conlon,

Copeland

et al. 2024

J. Cosmol. Astropart. Phys.

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We perform a detailed study of stringy moduli-driven cosmologies between the end of inflation and the commencement of the Hot Big Bang, including both the background and cosmological perturbations: a period that can cover half the lifetime of the universe on a logarithmic scale. Compared to the standard cosmology, stringy cosmologies with vacua that address the hierarchy problem motivate extended kination, tracker and moduli-dominated epochs involving significantly trans-Planckian field excursions. We analyse the cosmology within the framework of the Large Volume Scenario but explain how analogous cosmological features are expected in other string theory models characterized by final vacua located in the asymptotic regions of moduli space. Conventional effective field theory is unable to control Planck-suppressed operators and so such epochs require a stringy completion for a consistent analysis. Perturbation growth in these stringy cosmologies is substantially enhanced compared to conventional cosmological histories. The transPlanckian field evolution results in radical changes to Standard Model couplings during this history and we outline potential applications to baryogenesis, dark matter and gravitational wave production.

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