Primordial Black Holes Shape High-Energy Neutrino Production via Memory Burden Effect

Primordial black holes emit Standard Model and beyond-the-Standard-Model particles via Hawking radiation. The memory burden effect, which suppresses evaporation once half the black hole mass is lost, significantly impacts high-energy neutrino production. This suppression alters the muon neutrino flux, particularly at high energies. However, including heavy neutral leptons introduces additional neutrino production channels, counterbalancing the suppression. These findings affect the detectability of primordial black hole evaporation signatures in IceCube and constrain the parameter space of heavy neutral leptons in cosmological contexts.
Primordial black holes (PBHs), formed in the early universe, emit particles through Hawking radiation, including both Standard Model and beyond-the-Standard Model entities.

Recent studies have explored the memory burden effect, a gravitational backreaction that suppresses PBH evaporation once about half their mass is lost, impacting high-energy neutrino production. Researchers investigated how this suppression affects muon neutrino flux, considering scenarios with and without heavy neutral leptons (HNLs) as beyond-Standard Model states. Their findings reveal significant alterations in the neutrino energy spectrum, particularly at high energies, with HNLs potentially mitigating suppression by introducing additional production channels. These insights have implications for detecting PBH evaporation signatures and constraining HNL parameters in cosmological contexts.

The study was conducted by Arnab Chaudhuri from the National Astronomical Observatory of Japan and colleagues Koushik Pal and Rukmani Mohanta from the University of Hyderabad, published under the title Neutrino Fluence influenced by Memory Burdened Primordial Black Holes.

Primordial black holes reveal new physics via neutrino emissions from Hawking radiation.

The Standard Model of particle physics successfully describes elementary particles and their interactions but fails to explain several critical phenomena, such as the matter-antimatter imbalance, dark matter, dark energy, neutrino masses, and the absence of gravity within its framework. These gaps suggest the need for new physics beyond the Standard Model.

Primordial black holes (PBHs), formed in the early universe from quantum fluctuations, offer a promising avenue to explore beyond the Standard Model. Small-scale PBHs evaporate via Hawking radiation before Big Bang Nucleosynthesis, potentially emitting detectable neutrinos and contributing to an early matter-dominated era.

Hawking radiation emits particles thermally, with smaller black holes being hotter and evaporating faster. Detecting this radiation could confirm theories about PBH evaporation and provide insights into fundamental physics. Observational channels like gamma-rays, electrons, positrons, and neutrinos help constrain PBH abundance, particularly for those in the mass range of 10¹⁵ to 10¹⁷ grams.

The memory burden effect, a gravitational backreaction, suppresses evaporation once about half the PBH’s mass is lost. This suppression significantly alters high-energy neutrino production, affecting detectability in telescopes like IceCube. The presence of heavy neutral leptons (HNLs) as beyond-Standard Model states could counteract this suppression by introducing additional neutrino production channels.

These findings highlight the importance of studying PBH evaporation and HNL parameters for understanding cosmological phenomena. The interplay between memory burden effects and HNLs offers new avenues for exploring fundamental physics through neutrino observations.

Determine black hole evaporation time via Hawking radiation formula and integration.

The study of black hole evaporation via Hawking radiation has been a cornerstone of theoretical physics, offering insights into the interplay between quantum mechanics and general relativity. This research builds upon that foundation by introducing a novel approach to calculating the time until a primordial black hole (PBH) evaporates completely. The method begins with the well-established formula for the power emitted by a black hole due to Hawking radiation, which is inversely proportional to the square of its mass. By relating this power to the rate of mass loss, the researchers derive a differential equation that describes how the mass of the black hole decreases over time.

To solve this equation, the authors employ a technique involving the separation of variables and integration. This allows them to calculate the total time it takes for the black hole to evaporate completely, starting from an initial mass ( M_i ) down to zero. The result is a concise formula that expresses the evaporation time in terms of fundamental constants such as Planck’s constant, the speed of light ( c ), and Newton’s gravitational constant ( G ). This approach not only reaffirms the theoretical underpinnings of black hole evaporation but also introduces a methodological innovation by incorporating the memory burden effect, which accounts for gravitational backreactions that suppress evaporation once approximately half the PBH mass has been lost.

Including the memory burden effect is a significant advancement in this research. This phenomenon modifies the standard Hawking radiation model by introducing a feedback mechanism that reduces the rate of mass loss as the black hole approaches its final stages of evaporation. By integrating this effect into their calculations, the researchers provide a more accurate prediction of the time-integrated muon neutrino flux produced during PBH evaporation. This is particularly important because neutrinos are key messengers in astrophysics, and understanding their production mechanisms can shed light on both standard and beyond-standard model physics.

Furthermore, the study explores how the presence of heavy neutral leptons (HNLs), hypothetical particles that extend the Standard Model, influences the neutrino flux. The researchers demonstrate that HNLs can counterbalance the suppression caused by the memory burden effect by introducing additional channels for neutrino production. This interplay between the memory burden and HNLs has profound implications for the detectability of PBH evaporation signatures in neutrino telescopes like IceCube. By refining our understanding of these processes, the research enhances our ability to interpret potential observational data and constrain models of particle physics and cosmology.

In summary, this study represents a methodological advancement in black hole physics by incorporating the memory burden effect into the calculation of PBH evaporation times. The researchers’ approach provides a more accurate framework for understanding neutrino production and highlights the importance of considering beyond-standard model particles like HNLs in astrophysical phenomena. These findings underscore the intricate connections between quantum gravity, particle physics, and observational astronomy, offering new avenues for exploring the fundamental laws of nature.

Memory burden alters PBH neutrino signals with HNLs.

Primordial black holes (PBHs) are intriguing candidates for dark matter. They emit particles through Hawking radiation, which includes both Standard Model and beyond-the-Standard Model particles. This emission process is crucial as it offers potential observational signatures of PBHs.

A significant factor influencing PBH evaporation is the memory burden effect, a gravitational backreaction that suppresses further evaporation once approximately half the black hole’s mass has been lost. This suppression notably alters the high-energy neutrino flux, impacting the detectability of PBHs through experiments like IceCube.

Heavy neutral leptons (HNLs), beyond-the-Standard Model particles, introduces additional production channels for neutrinos. These HNLs can counterbalance the suppression caused by the memory burden effect, thereby affecting the energy spectrum of neutrinos and enhancing detection prospects.

In conclusion, the interplay between the memory burden effect and HNLs significantly influences the detectability of PBH evaporation signatures. These findings underscore the importance of considering beyond-the-Standard Model physics in cosmological studies, offering new insights into the role of PBHs as dark matter candidates and their implications for our understanding of the universe’s structure.

Understanding PBHs key to dark matter and particle physics.

Primordial black holes (PBHs) are emerging as a compelling candidate for dark matter, with their potential to influence cosmic structures and galaxy formation through gravitational effects. The article explores various detection methods, including gamma-ray bursts, Hawking radiation, and gravitational waves, each offering unique avenues to confirm the existence of PBHs.

The memory burden effect, a gravitational backreaction that suppresses black hole evaporation once approximately half the PBH mass is lost, significantly impacts neutrino production. This effect alters the high-energy neutrino spectrum, particularly at higher energies, affecting detectability in telescopes like IceCube.

As the beyond-the-Standard Model states, heavy neutral leptons (HNLs) can counterbalance this suppression by introducing additional neutrino production channels. Their presence modifies the muon neutrino flux, offering new possibilities for detecting PBH evaporation signatures and expanding our understanding of cosmological parameters.

These findings underscore the importance of further research into detection techniques and the parameter space of HNLs. Future work should focus on refining models to account for the memory burden effect and exploring how HNLs influence neutrino fluence, enhancing our ability to detect PBH evaporation signals.

In conclusion, while PBHs present a promising dark matter candidate, continued investigation into their detection methods and associated phenomena is crucial. This research will not only advance our understanding of cosmic structures but also shed light on the role of beyond-the-Standard Model particles in the universe’s composition.