Resurrecting low-mass axion dark matter via a dynamical QCD scale

Heurtier, Lucien; Huang, Fei; Tait, Tim M. P.

doi:10.1007/jhep12(2021)216

Cited by 12 publications

(10 citation statements)

References 39 publications

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“…5, where region 3 for constant axion mass starts above the blue line T osc = T c . There, as found in our analysis, the relic density is independent of T eq and the smallest axion mass that can fulfil the whole DM density is, for β = 3 m a ∼ 10 −8 eV for T eq 10 4 GeV, (55) and for β = 2 m a ∼ 10 −10 eV for T eq 4 GeV. (56) Numerically in Fig.…”

Section: Constant Axion Masssupporting

confidence: 79%

“…The most straightforward approach is to consider that in the case of the pre-inflationary scenario, there is a very small initial misalignment angle θ i , to compensate for a higher f a scale shifting it to be as high as ∼ 10 16 GeV, as allowed by bounds on isocurvature perturbations. Another way to open up the axion DM window to smaller masses or higher PQ scales invokes the coupling of the axion to some other field, for instance, to a hidden photon [50,51], or if the axion potential was much larger in the very early universe [52][53][54][55]. A different possibility to expand the range masses has been to consider a nonstandard cosmological (NSC) history in the early universe, such that entropy is injected into the thermal bath, diluting the axion energy density.…”

Section: Introductionmentioning

confidence: 99%

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New opportunities for axion dark matter searches in nonstandard cosmological models

Arias,

Bernal,

Karamitros

et al. 2021

Preprint

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We study axion dark matter production from a misalignment mechanism in scenarios featuring a general nonstandard cosmology. Before the onset of Big Bang nucleosynthesis, the energy density of the universe is dominated by a particle field φ described by a general equation of state ω. The ensuing enhancement of the Hubble expansion rate decreases the temperature at which axions start to oscillate, opening this way the possibility for axions heavier than in the standard window. This is the case for kination, or in general for scenarios with ω > 1/3. However, if ω < 1/3, as in the case of an early matter domination, the decay of φ injects additional entropy relative to the case of the standard model, diluting this way the preexisting axion abundance, and rendering lighter axions viable. For a misalignment angle 0.5 < θ i < π/ √ 3, the usual axion window becomes expanded to 4 × 10 −9 eV m a 2 × 10 −5 eV for the case of an early matter domination, or to 2 × 10 −6 eV m a 10 −2 eV for the case of kination. Interestingly, the coupling axion-photon in such a wider range can be probed with next generation experiments such as ABRACADABRA, KLASH, ADMX, MADMAX, and ORGAN. Axion dark matter searches may therefore provide a unique tool to probe the history of the universe before Big Bang nucleosynthesis.

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Section: Constant Axion Masssupporting

confidence: 79%

Section: Introductionmentioning

confidence: 99%

New opportunities for axion dark matter searches in nonstandard cosmological models

Arias,

Bernal,

Karamitros

et al. 2021

Preprint

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“…The QCD axion potential is well-known to be generated by non-perturbative effects around the QCD scale. At high temperature, the axion potential is unconstrained and can arise from a variety of PQ breaking effects [152,153,[165][166][167][168].…”

Section: Axion Model Realizations -Class a 6 Model A: An Axion-only R...mentioning

confidence: 99%

“…If the temperature is smaller than the fermion mass, T < y √ √, the heavy fermions are absent of the thermal plasma and must be integrated out. In that case, the scalar field can decay into gauge boson through a loop of fermions [165,167,168], cf. diagram c in Fig.…”

Section: G Radial Damping G1 Thermalizationmentioning

confidence: 99%

Kination cosmology from scalar fields and gravitational-wave signatures

Gouttenoire¹,

Servant²,

Simakachorn³

2021

Preprint

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Kination denotes an era in the cosmological history corresponding to an equation of state ω = +1 such that the total energy density of the universe redshifts as the sixth inverse power of the scale factor. This arises if the universe is dominated by the kinetic energy of a scalar field. It has often been motivated in the literature as an era following inflation, taking place before the radiation era. In this paper, we review instead the possibility that kination is disconnected from primordial inflation and occurs much later, inside the Standard Model radiation era. We study the implications on all main sources of primordial gravitational waves. We show how this leads to very distinctive peaked spectra in the stochastic background of long-lasting cosmological sources of gravitational waves, namely the irreducible gravitational waves from inflation, and gravitational waves from cosmic strings, both local and global, with promising observational prospects. We present model-independent signatures and detectability predictions at LIGO, LISA, ET, CE, BBO, as a function of the energy scale and duration of the kination era. We then argue that such intermediate kination era is in fact symptomatic in a large class of axion models. We analyse in details the scalar field dynamics, the working conditions and constraints in the underlying models. We present the gravitational-wave predictions as a function of particle physics parameters. We derive the general relation between the gravitational-wave signal and the axion dark matter abundance as well as the baryon asymmetry. We investigate the predictions for the special case of the QCD axion. The key message is that gravitational-waves of primordial origin represent an alternative experimental probe of axion models.

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“…At this time, the Universe may deviate dramatically from our extrapolation based on the SM, due to unforeseen Physics beyond the Standard Model. Indeed, explorations of non-standard cosmological histories, including a period of early matter domination [8], late entropy injection [9], and modifications of fundamental parameters such as the strength of the SU(3) coupling [10,11] have all been shown to lead to dramatically different expectations in the mapping of WIMP parameter space onto its predicted abundance in the early Universe.…”

Section: Jhep02(2022)047mentioning

confidence: 99%

Dark matter freeze-out during SU(2)L confinement

Howard

Ipek

Tait

et al. 2022

J. High Energ. Phys.

Self Cite

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We explore the possibility that dark matter is a pair of vector-like fermionic SU(2)L doublets and propose a novel mechanism of dark matter production that proceeds through the confinement of the weak sector of the Standard Model. This confinement phase causes the Standard Model doublets and dark matter to confine into pions. The dark pions freeze-out before the weak sector deconfines and generate a relic abundance of dark matter. We solve the Boltzmann equations for this scenario to determine the scale of confinement and constituent dark matter mass required to produce the observed relic density. We determine which regions of this parameter space evade direct detection, collider bounds, and successfully produce the observed relic density of dark matter. For a TeV scale pair of vector-like fermionic SU(2)L doublets, we find the weak confinement scale to be ∼ 700 TeV.

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Resurrecting low-mass axion dark matter via a dynamical QCD scale

Cited by 12 publications

References 39 publications

New opportunities for axion dark matter searches in nonstandard cosmological models

New opportunities for axion dark matter searches in nonstandard cosmological models

Kination cosmology from scalar fields and gravitational-wave signatures

Dark matter freeze-out during SU(2)L confinement

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