Axion cosmology with its scalar superpartner

Hashimoto, Masashi; Izawa, Ken-Iti; Yamaguchi, Masahiro; Yanagida, Tsutomu T.

doi:10.1016/s0370-2693(98)00887-9

Cited by 35 publications

(60 citation statements)

References 27 publications

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“…However, with dilution from a saxion condensate this limit is weakened by 3-4 orders of magnitude [16][17][18]. Hence we also explore the abundance of axion dark matter, finding regions of parameter space in both DFSZ [19,20] and KSVZ [21,22] models where it can be a significant component of dark matter.…”

Section: Jhep07(2017)125mentioning

confidence: 99%

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Saxion cosmology for thermalized gravitino dark matter

DʼEramo

Hall

et al. 2017

J. High Energ. Phys.

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In all supersymmetric theories, gravitinos, with mass suppressed by the Planck scale, are an obvious candidate for dark matter; but if gravitinos ever reached thermal equilibrium, such dark matter is apparently either too abundant or too hot, and is excluded. However, in theories with an axion, a saxion condensate is generated during an early era of cosmological history and its late decay dilutes dark matter. We show that such dilution allows previously thermalized gravitinos to account for the observed dark matter over very wide ranges of gravitino mass, keV < m 3/2 < TeV, axion decay constant, 10 9 GeV < f a < 10 16 GeV, and saxion mass, 10 MeV < m s < 100 TeV. Constraints on this parameter space are studied from BBN, supersymmetry breaking, gravitino and axino production from freeze-in and saxion decay, and from axion production from both misalignment and parametric resonance mechanisms. Large allowed regions of (m 3/2 , f a , m s ) remain, but differ for DFSZ and KSVZ theories. Superpartner production at colliders may lead to events with displaced vertices and kinks, and may contain saxions decaying to (W W, ZZ, hh), gg, γγ or a pair of Standard Model fermions. Freeze-in may lead to a sub-dominant warm component of gravitino dark matter, and saxion decay to axions may lead to dark radiation.

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Section: Jhep07(2017)125mentioning

confidence: 99%

“…The axion is produced by the usual misalignment mechanism but now we need to consider the effect of saxion dilution [16][17][18]. The axion field value is initially displaced from the minimum today by an amount f a θ i , where θ i is the misalignment angle.…”

Section: Misalignment Axion Contribution To Dark Mattermentioning

confidence: 99%

Saxion cosmology for thermalized gravitino dark matter

DʼEramo

Hall

et al. 2017

J. High Energ. Phys.

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“…In the SUSY axion model, the scalar partner of the axion, saxion, and the fermionic superpartner of the axion, axino, are included in the PQ supermultiplet and they take significant roles in cosmology [17,18,19,20,21,22,23,24]. In this section, we focus on the dynamics of the saxion and verify that the mechanism shown in the previous section is applicable.…”

Section: Application To a Supersymmetric Axion Modelmentioning

confidence: 99%

Revisiting the cosmological coherent oscillation

2013

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It is often the case that scalar fields are produced in the early Universe in the form of coherent oscillation. These scalar fields may have huge abundances and affect the evolution of the Universe. In particular, if the lifetime is long enough, they may cause cosmological disasters. We revisit the issue of coherent oscillation of the scalar field when it couples with another oscillating scalar field, and find a situation that the abundance, or the amplitude of the oscillation, is significantly reduced by a variant type of the adiabatic suppression mechanism. As a concrete example, it is applied to the saxion, a flat direction in the supersymmetric axion model, and we show that the cosmological saxion problem is solved in a particular setup.

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“…f The saxion may have a coupling with the axion, which enables the saxion to decay into two axions. If the saxion dominantly decays into the axions, it can be cosmologically problematic [25]. However, it is model-dependent whether this process dominates the saxion decay.…”

Section: Dark Matter From Saxion Decaymentioning

confidence: 99%

Nonthermal production of dark matter from a late-decaying scalar field at an intermediate scale

Endo

Takahashi

2006

Phys. Rev. D

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We examine non-thermal dark matter production from a late-decaying scalar field, with a particular attention on non-renormalizable operators of D = 5 through which the scalar field decays into the standard model particles and their superpartners. We show that almost the same number of superparticles as that of particles are generally produced from the decay. To avoid the gravitino overproduction problem, the decay is favored to proceed via interactions with an intermediate cut-off scale M ≪ M P . This should be contrasted to the conventional scenario using the modulus decay. The bosonic supersymmetry partner of the axion, i.e., saxion, is proposed as a natural candidate for such late-decaying scalar fields. We find that a right amount of the wino/higgsino dark matter with a mass of O(100) GeV is obtained for the saxion mass around the weak scale and axion decay constant, F A = O(10 9−12 ) GeV.

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Axion cosmology with its scalar superpartner

Cited by 35 publications

References 27 publications

Saxion cosmology for thermalized gravitino dark matter

Saxion cosmology for thermalized gravitino dark matter

Revisiting the cosmological coherent oscillation

Nonthermal production of dark matter from a late-decaying scalar field at an intermediate scale

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