Primordial black holes and Co-Decaying dark matter

Georg, Julian; Melcher, Brandon; Watson, Scott

doi:10.1088/1475-7516/2019/11/014

Cited by 10 publications

(7 citation statements)

References 92 publications

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“…When the hidden sector is out of equilibrium with the SM in the early universe, a wide variety of possible cosmic histories for dark matter are newly possible, together with avenues for discovery distinct from standard WIMP search strategies. Exotic thermal evolution in a decoupled dark sector can lead to substantial changes in DM properties relative to a traditional WIMP (e.g., [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]). Decoupled dark sectors can also induce early departures from the standard radiation-dominated evolution of the universe [11,20], or admit substantial amounts of relic dark radiation without violating the stringent bounds from Planck, ∆N eff < 0.36 at 95% confidence [2].…”

Section: Jhep08(2019)151mentioning

confidence: 99%

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Reheating in two-sector cosmology

Adshead

Ralegankar

Shelton

2019

J. High Energ. Phys.

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We analyze reheating scenarios where a hidden sector is populated during reheating along with the sector containing the Standard Model. We numerically solve the Boltzmann equations describing perturbative reheating of the two sectors, including the full dependence on quantum statistics, and study how quantum statistical effects during reheating as well as the non-equilibrium inflaton-mediated energy transfer between the two sectors affects the temperature evolution of the two radiation baths. We obtain new power laws describing the temperature evolution of fermions and bosons when quantum statistics are important during reheating. We show that inflaton-mediated scattering is generically most important at radiation temperatures T ∼ M φ /4, and build on this observation to obtain analytic estimates for the temperature asymmetry produced by asymmetric reheating. We find that for reheating temperatures T rh M φ /4, classical perturbative reheating provides an excellent approximation to the final temperature asymmetry, while for T rh M φ /4, inflaton-mediated scattering dominates the population of the colder sector and thus the final temperature asymmetry. We additionally present new techniques to calculate energy transfer rates between two relativistic species at different temperatures.

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Section: Jhep08(2019)151mentioning

confidence: 99%

“…where q xy is the component of q along x − y plane. Hence, the delta function in dI 13 can be transformed to impose conditions on q 0 and | q xy |. The corresponding Jacobian for transforming the Dirac delta conditions is…”

Section: Jhep08(2019)151mentioning

confidence: 99%

Reheating in two-sector cosmology

Adshead

Ralegankar

Shelton

2019

J. High Energ. Phys.

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“…PBHs formed during radiation domination are believed to have negligible spin [5]. On the other hand, PBHs formed during an early matter-dominated era (EMDE) [6][7][8][9] could have sizeable to near-extremal spin [10][11][12]. PBHs can also accumulate some spin either through early accretion processes [5] or through hierarchical mergers [13].…”

Section: Introductionmentioning

confidence: 99%

“…EMDEs are highly motivated due to the ubiquity of moduli in string theory and have been extensively studied in recent years in the context of dark matter [25][26][27][28][29][30] and baryogenesis [31]. Detailed studies of PBHs formed during an EMDE have been performed by [7][8][9], with a focus on long-lived PBHs existing in the current Universe, and their interplay with dark matter physics. PBHs that evaporated before BBN are harder to constrain 3 .…”

Section: Introductionmentioning

confidence: 99%

Precision Calculation of Dark Radiation from Spinning Primordial Black Holes and Early Matter Dominated Eras

Arbey,

Auffinger,

Sandick

et al. 2021

Preprint

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We present precision calculations of dark radiation in the form of gravitons coming from Hawking evaporation of spinning primordial black holes (PBHs) in the early Universe. Our calculation incorporates a careful treatment of extended spin distributions of a population of PBHs, the PBH reheating temperature, and the number of relativistic degrees of freedom. We compare our precision results with those existing in the literature, and show constraints on PBHs from current bounds on dark radiation from BBN and the CMB, as well as the projected sensitivity of CMB Stage 4 experiments. As an application, we consider the case of PBHs formed during an early matter-dominated era (EMDE). We calculate graviton production from various PBH spin distributions pertinent to EMDEs, and find that PBHs in the entire mass range up to 10 9 g will be constrained by measurements from CMB Stage 4 experiments, assuming PBHs come to dominate the Universe prior to Hawking evaporation. We also find that for PBHs with monochromatic spins a * > 0.81, all PBH masses in the range 10 −1 g < MBH < 10 9 g will be probed by CMB Stage 4 experiments.

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“…This novel mechanism was proposed in [37] under the name of "co-decaying dark matter". Thereafter a few studies have been performed on this topic concentrating on astrophysical implications like small scale structure formation [38] and formation of primordial black hole [39]. In this co-decaying framework, we have considered a temperature T , different from the SM temperature T , in the dark sector, which is a natural choice as the two sectors are not in thermal contact.…”

Section: Introductionmentioning

confidence: 99%

When freeze-out occurs due to a non-Boltzmann suppression: a study of degenerate dark sector

Biswas

Ganguly

Roy

2021

J. High Energ. Phys.

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Exponential suppression or commonly known as the Boltzmann suppression in the number density of dark matter is the key ingredient for creating chemical imbalance prior to the usual thermal freeze-out. A degenerate/quasi-degenerate dark sector can experience a different exponential suppression in the number density analogous to the radioactive decay law leading to a delayed freeze-out mechanism of dark matter known as the co-decaying dark matter. In this work, we study the dynamics of a multicomponent dark matter from thermally decoupled degenerate dark sector in a hidden U(1)X extension of the Standard Model. We compute the relic density of dark matter frozen-out through the co-decaying mechanism by solving four coupled Boltzmann equations. We demonstrate how temperature T′ of the dark sector changes due to all types of 3 → 2 and 2 → 2 interactions along with the eternal expansion of the Universe. We find that 3 → 2 interactions enhance T′ by producing energetic particles in the dark sector while the excess heat is transferred by 2 → 2 interactions to the entire dark sector. As the direct detection is possible only through the feeble portal couplings, we investigate the neutrino and γ-ray signals from dark matter annihilation via one step cascade processes and compare our results with the measured fluxes of atmospheric neutrinos by Super-Kamiokande and diffuse γ-rays by Fermi-LAT, EGRET, INTEGRAL collaborations. We find that the present scenario easily evades all the existing bounds from atmospheric neutrino and diffuse γ-ray observations for degenerate dark sector. However, the constraints are significant for quasi degenerate scenario.

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Primordial black holes and Co-Decaying dark matter

Cited by 10 publications

References 92 publications

Reheating in two-sector cosmology

Reheating in two-sector cosmology

Precision Calculation of Dark Radiation from Spinning Primordial Black Holes and Early Matter Dominated Eras

When freeze-out occurs due to a non-Boltzmann suppression: a study of degenerate dark sector

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