Dark sector production and baryogenesis from not quite black holes *

Aydemir, Ufuk; Ren, Jing

doi:10.1088/1674-1137/abf9ff

Cited by 4 publications

(11 citation statements)

References 156 publications

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“…The rate for this is proportional to exp(−π| ⃗ E crit |/| ⃗ E|). We can use the Schwinger effect as an exemplar to envision pair production in the expanding universe (Audretsch and Schaefer, 1978;Martin, 2008). Imagine a pair of virtual particles being pulled apart due to the expansion of the universe.…”

Section: Introductionmentioning

confidence: 99%

Cosmological gravitational particle production of massive spin-2 particles

Kolb

Ling

Long

et al. 2023

J. High Energ. Phys.

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The phenomenon of cosmological gravitational particle production (CGPP) is expected to occur during the period of inflation and the transition into a hot big bang cosmology. Particles may be produced even if they only couple directly to gravity, and so CGPP provides a natural explanation for the origin of dark matter. In this work we study the gravitational production of massive spin-2 particles assuming two different couplings to matter. We evaluate the full system of mode equations, including the helicity-0 modes, and by solving them numerically we calculate the spectrum and abundance of massive spin-2 particles that results from inflation on a hilltop potential. We conclude that CGPP might provide a viable mechanism for the generation of massive spin-2 particle dark matter during inflation, and we identify the favorable region of parameter space in terms of the spin-2 particle’s mass and the reheating temperature. As a secondary product of our work, we identify the conditions under which such theories admit ghost or gradient instabilities, and we thereby derive a generalization of the Higuchi bound to Friedmann-Robertson-Walker (FRW) spacetimes.

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Section: Introductionmentioning

confidence: 99%

Cosmological gravitational particle production of massive spin-2 particles

Kolb

Ling

Long

et al. 2023

J. High Energ. Phys.

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“…In addition to the misalignment mechanism, axions can also be produced from the 2-2-hole evaporation process. As could be inferred from our previous study [35]; this contribution is negligible compared to the DM abundance, and the axions directly produced from 2-2-holes can be hot and can make a meaningful contribution to the effective number of relativistic degrees of freedom in the early universe, N eff , which will be briefly discussed later in this paper. Due to the extreme constraints from Big Bang Nucleosynthesis (BBN) [34], we only focus on 2-2-holes small enough to complete their evaporation by the beginning of the BBN period.…”

Section: Introductionmentioning

confidence: 71%

“…[34] and as complimentary to particle DM in Ref. [35]. Therefore, in the case of axion DM we need to be careful to take into account the necessary constraints.…”

Section: Primordial 2-2-hole Dominationmentioning

confidence: 99%

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Not quite black holes as dark matter

2020

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We investigate the effects of an early cosmological period, dominated by primordial 2-2-holes, on axion dark matter. 2-2-holes emerge in quadratic gravity, a candidate theory of quantum gravity, as a new family of classical solutions for ultracompact matter distributions. These objects have a black hole exterior without an event horizon and hence, as a probable endpoint of gravitational collapse, they do not suffer from the information loss problem. Thermal 2-2-holes exhibit Hawking-like classical radiation and satisfy the entropy-area law. Moreover, these objects, unlike BHs, have a minimum allowed mass and hence naturally give rise to stable remnants. In this paper, we consider the remnant contribution to dark matter (DM) small and adopt the axion DM scenario by the misalignment mechanism. We show that a 2-2-hole domination phase in the evolution of the universe changes the axion mass window from the dark matter abundance constraints. The biggest effect occurs when the remnants have the Planck mass, which is the case for a strongly coupled quantum gravity. The change in abundance constraints for the Planck mass 2-2-hole remnants amounts to that of the Primordial Black Hole (PBH) counterpart. Therefore; since we use the revised constraints on the initial fraction of 2-2-holes from GWs, the results here can also be considered as the updated version of the PBH case. As a result, the lower limit on the axion mass is found as m a ∼ 10 −9 eV. Furthermore, the domination scenario itself constrains the remnant mass M min considerably. Given that we focus on the pre-BBN domination scenario in order not to interfere with BBN (Big Bang Nucleosynthesis) constraints, the remnant mass window becomes m Pl ≲ M min ≲ 0.1 g.

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“…Since the above equation has no solutions, the metric (8.5) does not have an event horizon. Similar horizonless exotic compact objects (named 2-2-holes remnants [58][59][60]) where discovered in Stelle's Gravity and proposed as candidate dark matter. Such 2-2-holes may be viewed as non-perturbative bound states of gravitons and massive spin-2 ghost-like states in quadratic gravity [61,62].…”

Section: Summary and Discussionmentioning

confidence: 86%

Stringballs and Planckballs for dark matter

Zhongyou

Netto

Burzillà

et al. 2022

J. High Energ. Phys.

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As a follow up of the seminal work by Guiot, Borquez, Deur, and Werner on “Graviballs and Dark Matter”, we explicitly show that in string theory, local and nonlocal higher derivative theories, as well as general asymptotically-free or finite theories, gravitationally interacting bound states can form when the energy is larger than the Planck energy. On the other hand, in higher derivative or nonlocal theories with interaction governed by a dimensionless or a dimensionful coupling constant, the bound states form when the energy is smaller than the Planck energy. Such bound states are allowed because of the softness of the scattering amplitudes in the ultraviolet region. Indeed, in such theories, the potential is finite while the force is zero or constant in r = 0. Finally, since the bound states that form in the early Universe may have an energy that ranges from the Planck mass to any arbitrarily large or small value, we argue that they can serve as dark matter candidates and/or as the seeds for the structure’s formation at large scale in the Cosmos.

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Dark sector production and baryogenesis from not quite black holes *

Cited by 4 publications

References 156 publications

Cosmological gravitational particle production of massive spin-2 particles

Cosmological gravitational particle production of massive spin-2 particles

Not quite black holes as dark matter

Stringballs and Planckballs for dark matter

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