Neutrino Emission and Plasma Heating from Primordial Black Holes: An Improved Approach to $N_{\mathrm{eff}}$ Constraints

Abstract

We investigate the impact of neutrino emission via Hawking radiation from primordial black holes (PBHs) on the cosmological effective number of neutrino species, $N_{\mathrm{eff}}$, after neutrino decoupling. By comparing this effect with observational limits, we derive bounds on the abundance of light PBHs. Our analysis incorporates two previously unaccounted-for effects: the emission of secondary neutrinos from unstable particles, which increases $N_{\mathrm{eff}}$, and the modification of the neutrino-photon temperature ratio due to particle emission heating the photon plasma, which lowers $N_{\mathrm{eff}}$. Overall, including these effects allows us to impose constraints on PBHs with initial masses in the range $10^9\mathrm{g}\lesssim M_{\mathrm{ini}}\lesssim 10^{13}\mathrm{g}$. However, our limits remain less stringent than those derived from Big Bang Nucleosynthesis.

26 pages, 4 figures. Major update. Changes: - Post-emission interactions of emitted unstable particles are now taken into account. - A more recent observational $N_{\mathrm{eff}}$ constraint is used for the bounds. - Various minor changes

References in corpus (42)

• An Introduction to PYTHIA 8.2
• DESI 2024 VI: Cosmological Constraints from the Measurements of Baryon Acoustic Oscillations
• Primordial Black Holes as Dark Matter
• Primordial Black Holes as Dark Matter: Recent Developments
• The Atacama Cosmology Telescope: DR6 Gravitational Lensing Map and Cosmological Parameters
• A Primer for Black Hole Quantum Physics
• The origins of massive black holes
• Primordial Black Hole Evaporation and Dark Matter Production: I. Solely Hawking radiation
• Primordial Black Hole Evaporation and Dark Matter Production: II. Interplay with the Freeze-In/Out Mechanism
• Dark Matter in the Time of Primordial Black Holes
• Gravitational dark matter production: primordial black holes and UV freeze-in
• Primordial black hole constraints with Hawking radiation -- a review
• Precision Calculation of Dark Radiation from Spinning Primordial Black Holes and Early Matter Dominated Eras
• Dark matter and dark radiation from evaporating Kerr primordial black holes
• Bounds on warm dark matter from Schwarzschild primordial black holes
• Axion Dark Matter in the Time of Primordial Black Holes
• Non-thermal Origin of Asymmetric Dark Matter from Inflaton and Primordial Black Holes
• Baryogenesis, Primordial Black Holes and MHz-GHz Gravitational Waves
• The Primordial Black Holes that Disappeared: Connections to Dark Matter and MHz-GHz Gravitational Waves
• Evaporation of Primordial Black Holes in the Early Universe: Mass and Spin Distributions
• Distinct signatures of spinning PBH domination and evaporation: doubly peaked gravitational waves, dark relics and CMB complementarity
• Primordial Black Hole Archaeology with Gravitational Waves from Cosmic Strings
• ALP Dark Matter in a Primordial Black Hole Dominated Universe
• Redshift Effects in Particle Production from Kerr Primordial Black Holes
• Superradiant Production of Heavy Dark Matter from Primordial Black Holes
• Primordial Black Hole Baryogenesis
• Recycled Dark Matter
• Limits on light primordial black holes from high-scale leptogenesis
• Formation of hot spots around small primordial black holes
• Primordial black hole versus inflaton
• Constraining the primordial black hole abundance through Big-Bang nucleosynthesis
• Superradiant Leptogenesis
• High-Energy and Ultra-High-Energy Neutrinos from Primordial Black Holes
• Regurgitated Dark Matter
• Primordial Black Holes Are True Vacuum Nurseries
• Impact of memory-burdened primordial black holes on high-scale leptogenesis
• Primordial Black Hole Neutrinogenesis of Sterile Neutrino Dark Matter
• Primordial neutrinos and new physics: novel approach to solving neutrino Boltzmann equation
• How new physics affects primordial neutrinos decoupling: Direct Simulation Monte Carlo approach
• New physics decaying into metastable particles: impact on cosmic neutrinos
• Dynamics of metastable Standard Model particles from long-lived particle decays in the MeV primordial plasma
• Thermalization and hotspot formation around small primordial black holes