Production and backreaction of spin-2 particles of SU(2) gauge field during inflation

Maleknejad, Azadeh; Komatsu, Eiichiro

doi:10.1007/jhep05(2019)174

Cited by 53 publications

(91 citation statements)

References 78 publications

(211 reference statements)

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“…Existing studies of P-violating bispectra and trispectra [62][63][64][65][66][67][68][69][70][71][72][73][74][75] require the presence of either tensor modes or broken rotational symmetry. These studies are thus aimed to probe the P or CP of the inflaton background or the gravitational interactions.…”

Section: Introductionmentioning

confidence: 99%

Probing P and CP violations on the cosmological collider

Liu

Tong

Wang

et al. 2020

J. High Energ. Phys.

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In direct analogy to the 4-body decay of a heavy scalar particle, the 4-point correlation function of primordial fluctuations carries P and CP information. The CP violation appears as a P-odd angular dependence in the imaginary part of the trispectrum in momentum space. We construct a model with axion-like couplings which leads to observably large CP-violating trispectrum for future surveys. Furthermore, we show the importance of on-shell particle production in observing P-and CP-violating signals. It is impossible to observe these signals from local 4-scalar EFT operators that respect dS isometries, and thus any such observation can rule out single-field EFT with sufficiently small slow-roll parameters. This calculation opens a new frontier of studying P and CP at very high energy scales. * Electronic address: taoliu@ust.hk † Electronic address: xtongac@connect.ust.hk ‡ Electronic address: phyw@ust.hk § Electronic address:

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Section: Introductionmentioning

confidence: 99%

Probing P and CP violations on the cosmological collider

Liu

Tong

Wang

et al. 2020

J. High Energ. Phys.

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“…12 Note that Ref. [25] introduces a more refined criterion based on the effect of the induced current on the gauge field background EOM. This corresponds to re-summing all non-linear terms and hence (as we have verified explicitly numerically), the condition δA 2 NA 1/2 /(Rψ) = 1/10 corresponds to an O(1) backreaction from the induced current.…”

Section: Resultsmentioning

confidence: 99%

The Different Regimes of Axion Gauge Field Inflation

Domcke

Sandner

2019

J. Cosmol. Astropart. Phys.

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In axion gauge field inflation an axion-like particle driving cosmic inflation is coupled to the Chern-Simons density of an Abelian or non-Abelian gauge group. In the case of a non-Abelian gauge group, this can lead to the formation of a stable, homogeneous and isotropic gauge field background. We study the dynamics of the inflaton and gauge fields in terms of the two effective coupling parameters: the gauge coupling and the axion decay constant. Starting from the Bunch-Davies vacuum in the far past, we find that the non-trivial gauge field background arises only significantly after the cosmic microwave background (CMB) scales have left the horizon. At these scales, the model thus closely resembles Abelian axion inflation, thereby naturally reconciling the tension of non-Abelian axion gauge field inflation with the latest CMB observations. We further consider two exemplary UV-completions of this setup: multiple Peccei-Quinn axions and axion monodromy in string theory. In both cases we find that the majority of the parameter space is excluded by theoretical or observational constraints. The remaining parameter space can be divided into three regimes. (i) For small gauge couplings we recover natural inflation. For large gauge couplings the non-Abelian gauge theory either (ii) mimics the Abelian theory or (iii) nonlinear interactions prohibit a linear analysis of the gauge field perturbations.

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“…It was found that the backreaction of the scalar particles on the SU (2) background is negligible in the viable parameter regions of the simplest axion-SU (2) models. In [33], the backreaction of the extra spin-2 field in this setup was analytically studied for all the inflationary models involving the SU (2) gauge field.…”

Section: Contentsmentioning

confidence: 99%

“…We also add an interaction between axion and the axial fermionic current, J µ5 ∂ µ ϕ/Λ, which is naturally expected in this type of models. We then calculate the backreaction of the fermions on the SU (2) and axion background dynamics during inflation, following the framework we have established in [31,33].…”

Section: Contentsmentioning

confidence: 99%

“…However, in both cases, the current increases like ξ 2 A in the very strong gauge field limit. Having computed J ± , we can compute their backreaction on the SU (2) gauge field background, ψ, by following [33]. Assuming slow-roll evolution of the axion-SU (2), i.e., where a dot is a derivative with respect to cosmic time and the field derivative of the effective potential of ψ is For the constraints due to the tensor and scalar backreactions see [31,33].…”

Section: Backreaction On the Su (2) Backgroundmentioning

confidence: 99%

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Production and backreaction of fermions from axion- SU(2) gauge fields during inflation

2020

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SU (2) gauge fields and axions can have a stable, isotropic and homogeneous configuration during inflation. However, couplings to other matter species lead to particle production, which in turn induces backreaction on and destabilization of the non-abelian and axion background. In this paper, we first study the particle production by a SU (2) gauge field coupled to a massive Dirac doublet. To carry out this calculation we have made two technical improvements compared to what has been done in the literature. First, we apply the anti-symmetrization of the operators to treat particles and anti-particles on equal footing, second, to deal with the UV divergences, we apply instantaneous subtraction. We find that, the backreaction of produced fermions on the SU (2) background is negligible for model parameters of observational interest. Next, we consider production of fermions due to coupling to the axion. The tree-level backreaction on the gauge fields, as well as on the axion, is vanishingly small. We also provide an estimate for the loop effects. arXiv:1905.09258v2 [hep-th]

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Production and backreaction of spin-2 particles of SU(2) gauge field during inflation

Cited by 53 publications

References 78 publications

Probing P and CP violations on the cosmological collider

Probing P and CP violations on the cosmological collider

The Different Regimes of Axion Gauge Field Inflation

Production and backreaction of fermions from axion- SU(2) gauge fields during inflation

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