Metastable conformal dark matter

Brax, Philippe; Kaneta, Kunio; Mambrini, Yann; Pierre, Mathias

doi:10.1103/physrevd.103.115016

Cited by 10 publications

(5 citation statements)

References 134 publications

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“…In various scenarios, a suppression from a large ultraviolet (UV) scale have been invoked to justify such a feeble coupling with the visible sector, from constructions inspired by Grand Unification Theory (GUT) [12,13] to high-scale supersymmetry [14][15][16][17]. More recently, several works have explored the possibility for such a feeble coupling to arise from the gravitational interactions [18][19][20][21][22][23][24][25][26][27][28], identifying this UV scale with the Planck scale M P . In these cases, dark matter production is very sensitive to the highest temperature achieved in the universe and to the (post-)inflationary dynamics of the universe.…”

Section: Motivationmentioning

confidence: 99%

Scalar Dark Matter Production from Preheating and Structure Formation Constraints

García¹,

Pierre²,

Verner³

2022

Preprint

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We investigate the out-of-equilibrium production of scalar dark matter (DM) from the inflaton condensate during inflation and reheating. We assume that this scalar couples only to the inflaton via a direct quartic coupling and is minimally coupled to gravity. We consider all possible production regimes: purely gravitational, weak direct coupling (perturbative), and strong direct coupling (nonperturbative). For each regime, we use different approaches to determine the dark matter phase space distribution and the corresponding relic abundance. For the purely gravitational regime, scalar dark matter quanta are copiously excited during inflation resulting in an infrared (IR) dominated distribution function and a relic abundance which overcloses the universe for a reheating temperature T reh > 34 GeV. A non-vanishing direct coupling induces an effective DM mass and suppresses the large IR modes in favor of ultraviolet (UV) modes and a minimal scalar abundance is generated when the interference between the direct and gravitational couplings is maximal. For large direct couplings, backreaction on the inflaton condensate is accounted for by using the Hartree approximation and lattice simulation techniques. Since scalar DM candidates can behave as non-cold dark matter, we estimate the impact of such species on the matter power spectrum and derive the corresponding constraints from the Lyman-α measurements. We find that they correspond to a lower bound on the DM mass of 3 × 10 −4 eV for purely gravitational production, and 20 eV for direct coupling production. We discuss the implications of these results.

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Section: Motivationmentioning

confidence: 99%

Scalar Dark Matter Production from Preheating and Structure Formation Constraints

García¹,

Pierre²,

Verner³

2022

Preprint

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“…The dominant contribution to the dilaton production is due to scattering processes involving top-Yukawa coupling (2.10), i.e. y t Q L Ht R , see also [21,23]. The condition for dilaton to be in thermal equilibrium reads as,…”

Section: Dilaton Decaysmentioning

confidence: 99%

“…However, assuming the conformal invariance breaking scale f v SM , it is natural that SM and DM are out of thermal equilibrium. Hence the possible DM production follows through the freeze-in mechanism, where DM is produced through the SM annihilation via the dilaton portal or through direct decays/annihilation of the dilaton field, see also [21][22][23][24].…”

Section: Introductionmentioning

confidence: 99%

Ultraviolet freeze-in dark matter through the dilaton portal

Ahmed¹,

Najjari²

2021

Preprint

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We consider a class of models where the Standard Model (SM) and dark matter (DM) belong to a conformal/scale-invariant theory at high energies. The scale invariance is broken spontaneously at scale f , and the corresponding Goldstone boson is the dilaton. In the low-energy theory, we assume DM interacts with the SM only through the dilaton portal suppressed by the conformal breaking scale f . Assuming f TeV, the portal interactions are very feeble, and hence the DM is not in thermal equilibrium with the SM bath. Therefore, ultraviolet freeze-in production of DM is realized through the dilaton portal, which is most effective at the maximum temperature of the SM bath. The temperature evolution critically depends on the reheating dynamics, which we parameterize by a general equation of state w and temperature at the end of reheating T rh . Implications of the reheating dynamics are studied for DM production in this framework. We have identified regions of parameter space that lead to the observed DM relic abundance for a wide range of DM masses and reheating temperatures for a scalar, vector, or fermion DM.

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“…Both reheating and subsequent thermalization may have direct impact on new physics beyond the Standard Model such as generating dark matter particles, especially a so-called freeze-in massive particle (FIMP) dark matter [74][75][76][77][78][79][80][81][82][83][84][85][86][87][88][89][90][91]. Among various portal couplings to produce FIMP out of thermal bath, the graviton exchange is the minimal contribution [92][93][94][95][96][97][98], namely, annihilation of the thermal bath particles to produce a pair of dark matter through a single graviton exchange.…”

Section: Introductionmentioning

confidence: 99%

Boltzmann or Bogoliubov? Approaches compared in gravitational particle production

Kaneta

Lee

Oda

2022

J. Cosmol. Astropart. Phys.

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Gravitational particle production is a minimal contribution to reheating the Universe after the end of inflation. To study this production channel, two different approaches have commonly been considered, one of which is based on the Boltzmann equation, and the other is based on the Bogoliubov transformation. Each of these has pros and cons in practice. The collision term in the Boltzmann equation can be computed based on quantum field theory in the Minkowski spacetime, and thus many techniques have been developed so far. On the other hand, the Bogoliubov approach may deal with the particle production beyond the perturbation theory and is able to take into account the effect of the curved spacetime, whereas in many cases one should rely on numerical methods, such as lattice computation. We show by explicit numerical and analytical computations of the purely gravitational production of a scalar that these two approaches give consistent results for particle production with large momenta during reheating, whereas the Boltzmann approach is not capable of computing particle production out of vacuum during inflation. We also provide analytic approximations of the spectrum of produced scalar with/without mass for the low momentum regime obtained from the Bogoliubov approach.

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Metastable conformal dark matter

Cited by 10 publications

References 134 publications

Scalar Dark Matter Production from Preheating and Structure Formation Constraints

Scalar Dark Matter Production from Preheating and Structure Formation Constraints

Ultraviolet freeze-in dark matter through the dilaton portal

Boltzmann or Bogoliubov? Approaches compared in gravitational particle production

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