Robust cosmological constraints on axion-like particles

Depta, Paul Frederik; Hufnagel, Marco; Schmidt-Hoberg, Kai

doi:10.1088/1475-7516/2020/05/009

Cited by 106 publications

(107 citation statements)

References 74 publications

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“…BBN represents a very stringent constraint on light species that were not in thermal equilibrium during BBN but that were still capable of modifying the expansion history of the early Universe. Relevant examples of these scenarios include axions [719,720], axion-like particles [721,722], majorons [723,724], and weakly coupled dark sectors [725,726].…”

Section: Bbn Constraints On Nonstandard Cosmologiesmentioning

confidence: 99%

The First Three Seconds: a Review of Possible Expansion Histories of the Early Universe

Allahverdi¹,

Amin²,

Berlin³

et al. 2021

TheOJA

200

140

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It is commonly assumed that the energy density of the Universe was dominated by radiation between reheating after inflation and the onset of matter domination 54,000 years later. While the abundance of light elements indicates that the Universe was radiation dominated during Big Bang Nucleosynthesis (BBN), there is scant evidence that the Universe was radiation dominated prior to BBN. It is therefore possible that the cosmological history was more complicated, with deviations from the standard radiation domination during the earliest epochs. Indeed, several interesting proposals regarding various topics such as the generation of dark matter, matter-antimatter asymmetry, gravitational waves, primordial black holes, or microhalos during a nonstandard expansion phase have been recently made. In this paper, we review various possible causes and consequences of deviations from radiation domination in the early Universe -taking place either before or after BBN -and the constraints on them, as they have been discussed in the literature during the recent years.

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Section: Bbn Constraints On Nonstandard Cosmologiesmentioning

confidence: 99%

The First Three Seconds: a Review of Possible Expansion Histories of the Early Universe

Allahverdi¹,

Amin²,

Berlin³

et al. 2021

TheOJA

200

140

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“…While originally motivated as a solution to the strong CP problem [18][19][20], they are ubiquitous in many high energy physics theories [21][22][23][24]. A variety of experimental efforts are underway to detect axions and axion-like particles (ALPs) in the laboratory [25][26][27][28] and through their unique astrophysical and cosmological signatures [29][30][31][32][33][34][35][36][37][38]. Many of these searches rely upon a coupling of the axion field φ(x, t) to electromagnetism via the interaction g aγ φE • B.…”

Section: Introductionmentioning

confidence: 99%

Dipole radiation and beyond from axion stars in electromagnetic fields

Amin

Long

Mou

et al. 2021

J. High Energ. Phys.

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We investigate the production of photons from coherently oscillating, spatially localized clumps of axionic fields (oscillons and axion stars) in the presence of external electromagnetic fields. We delineate different qualitative behaviour of the photon luminosity in terms of an effective dimensionless coupling parameter constructed out of the axion-photon coupling, and field amplitude, oscillation frequency and radius of the axion star. For small values of this dimensionless coupling, we provide a general analytic formula for the dipole radiation field and the photon luminosity per solid angle, including a strong dependence on the radius of the configuration. For moderate to large coupling, we report on a non-monotonic behavior of the luminosity with the coupling strength in the presence of external magnetic fields. After an initial rise in luminosity with the coupling strength, we see a suppression (by an order of magnitude or more compared to the dipole radiation approximation) at moderately large coupling. At sufficiently large coupling, we find a transition to a regime of exponential growth of the luminosity due to parametric resonance. We carry out 3+1 dimensional lattice simulations of axion electrodynamics, at small and large coupling, including non-perturbative effects of parametric resonance as well as backreaction effects when necessary. We also discuss medium (plasma) effects that lead to resonant axion to photon conversion, relevance of the coherence of the soliton, and implications of our results in astrophysical and cosmological settings.

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“…For the lowest masses we will consider (a few MeV), ALP and/or dark sector particle could remain in thermal equilibrium until the time of neutrinos decoupling and BBN, and this would yield additional constraints, see e.g. [61][62][63]. In this work, given that we do not specify the detailed structure of the dark sector, we will simply assume that a mechanism exists that allows to escape possible constraints from DM overabundance or from other cosmological arguments.…”

Section: Jhep06(2021)009mentioning

confidence: 99%

Invisible decays of axion-like particles: constraints and prospects

Giacchino

Nardi

Raggi

2021

J. High Energ. Phys.

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Axion-like particles (ALPs) can provide a portal to new states of a dark sector. We study the phenomenology of this portal when the ALP mainly decays invisibly, while its interaction with the standard model sector proceeds essentially via its coupling to electrons and/or photons. We reanalyse existing limits from various collider and beam dump experiments, including in particular ALP production via electron/positron interactions, in addition to the usual production through ALP-photon coupling. We further discuss the interplay between these limits and the intriguing possibility of explaining simultaneously the muon and electron magnetic moment anomalies. Finally, we illustrate the prospects of ALP searches at the LNF positron fixed-target experiment PADME, and the future reach of an upgraded experimental setup.

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Robust cosmological constraints on axion-like particles

Cited by 106 publications

References 74 publications

The First Three Seconds: a Review of Possible Expansion Histories of the Early Universe

The First Three Seconds: a Review of Possible Expansion Histories of the Early Universe

Dipole radiation and beyond from axion stars in electromagnetic fields

Invisible decays of axion-like particles: constraints and prospects

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