Antimatter Blackhole Model

Abstract

We propose a speculative cosmological scenario where the observed asymmetry between matter and antimatter arises not from baryogenesis or CP violation, but as a natural result of inflation. In this hypothesis, matter and antimatter were created in equal quantities but separated by the rapid expansion of space during inflation, suppressing annihilation. Antimatter-rich regions collapsed into supermassive black holes, while matter dispersed and later aggregated around these gravitational centers to form galaxies. We further propose that interactions between antimatter and dark matter may have facilitated early collapse, and that the observed 511 keV gamma-ray line may originate from Hawking radiation processes near primordial black holes.

1. Introduction

The matter-antimatter asymmetry is one of the most puzzling problems in cosmology. Conventional models such as electroweak baryogenesis and leptogenesis attempt to explain this asymmetry, but lack direct observational support. Simultaneously, the presence of supermassive black holes in the early universe presents another mystery regarding structure formation. We explore the possibility that antimatter regions, separated from matter by inflation, collapsed into black holes which later seeded galaxies, addressing both of these mysteries under a single framework.

2. Inflation and Particle Separation

During inflation, space expanded faster than the speed of light in comoving coordinates, causing causally connected particles to become effectively isolated. If matter-antimatter pairs were produced prior to or during inflation, this expansion could stretch them beyond each other's causal horizon, suppressing annihilation. The critical separation scale is set by the comoving Hubble horizon:

This inflation-driven separation forms the foundation for the spatial segregation between matter and antimatter.

3. Gravitational Collapse of Antimatter Regions: Beyond the Standard Model

In standard general relativity and the Standard Model of particle physics, gravity couples universally to energy and momentum, regardless of whether it originates from matter or antimatter. Therefore, no intrinsic difference in gravitational behavior is expected between matter and antimatter.

However, we propose that dark matter may interact differently with antimatter compared to matter. Specifically, antimatter could experience an enhanced or distinct form of interaction with dark matter—possibly mediated by a hidden-sector scalar field. This could lead to an effective compression of antimatter regions in the early universe, making them more susceptible to gravitational collapse.

A testable prediction of this hypothesis is that dark matter candidates such as neutrinos should exhibit significantly higher interaction cross-sections with antimatter than with matter. For instance, neutrino scattering events may be measurably more frequent in antimatter-dense environments (e.g., antihydrogen clouds), offering a pathway for experimental validation.

4. Galaxy Formation Around Primordial Black Holes

Recent studies support the idea that galaxies may have formed around pre-existing supermassive black holes. In our model, antimatter-driven black holes acted as gravitational centers around which baryonic matter accreted, giving rise to galaxies. This aligns with the M-sigma relation observed in galactic dynamics:

5. The 511 keV Gamma-Ray Line and Hawking Radiation

Since the 1970s, an intense 511 keV gamma-ray signal has been detected from the galactic center, attributed to electron–positron annihilation. The origin of these positrons remains unresolved.

We propose that Hawking radiation near primordial black holes could produce electron–positron pairs. When one member of the pair is captured by the black hole and the other escapes—especially the positron—it may interact with ambient electrons, resulting in the emission of 511 keV photons. Though sparse, these interactions could cumulatively explain a portion of the observed gamma-ray line, especially in dense gravitational environments.

6. Observational and Theoretical Implications

This hypothesis introduces several speculative but intriguing directions:

It suggests a novel coupling between antimatter and dark matter.

It aligns with the lack of observable large-scale annihilation zones, as antimatter may be sequestered within black holes.

It proposes a mechanism to indirectly source the 511 keV signal via Hawking radiation.

Future observational efforts—particularly in high-resolution gamma-ray astronomy and neutrino detection experiments—may be able to confirm or constrain these claims. Even if indirect, such evidence could support a more nuanced understanding of the early universe's matter-antimatter dynamics.

7. Conclusion

This revised model offers a speculative but unified perspective on three cosmic enigmas: the matter-antimatter asymmetry, the presence of early supermassive black holes, and the 511 keV gamma-ray emission. By invoking inflationary separation, differential dark matter interactions, and Hawking radiation, the framework remains largely compatible with the Standard Model while introducing testable extensions beyond it. This invites further theoretical refinement and observational inquiry.