English

Strongly Coupled Dark Energy Cosmologies yielding large mass Primordial Black Holes

Cosmology and Nongalactic Astrophysics 2019-04-10 v4

Abstract

Large primordial Black Hole (PBH) formation is enhanced if strongly coupled scalar and spinor fields (Φ\Phi and ψ\psi) are a stable cosmic component since the primeval radiative expansion (SCDEW models). In particular, we show that PBH formation is easier at a specific time, i.e., when the asymptotic mass mHm_H, acquired by the ψ\psi field at the higgs scale, becomes dominant, so that the typical BH mass MBHM_{BH} depends on mHm_H value. For instance, if mH100m_H \sim 100\, eV (1(1 keV)) and the coupling β8.35(37)\beta \sim 8.35 (37), PBH with MBH107108M_{BH} \simeq 10^7-10^8 (103104)M(10^3-10^4)\, M_\odot could form. The very mechanism enhancing PBH formation also causes technical difficulties to evaluate the transfer function of SCDEW models at high kk. A tentative solution of this problem leaves only minor discrepancies from Λ\LambdaCDM, also at these scales, gradually vanishing for greater mHm_H values. We conclude that, for suitable parameter choices, SCDEW models could be the real physics underlying Λ\Lambda CDM, so overcoming its fine tuning and coincidence problems, with the extra bonus of yielding large BH seeds.

Keywords

Cite

@article{arxiv.1807.11841,
  title  = {Strongly Coupled Dark Energy Cosmologies yielding large mass Primordial Black Holes},
  author = {S. A. Bonometto and R. Mainini and M. Mezzetti},
  journal= {arXiv preprint arXiv:1807.11841},
  year   = {2019}
}

Comments

15 pages, 15 figures; accepted for publication in MNRAS. Updated to match accepted version