Chemical evolution of antimatter domains in early Universe
A. I. Dembitskaia, Stephane Weiss, M. Yu. Khlopov, M. A. Krasnov
TL;DR
The paper investigates whether localized antimatter domains could persist within a predominantly baryonic Universe, focusing on their chemical evolution and boundary interactions with surrounding matter. It combines PNGB-based spontaneous baryogenesis to establish antimatter domains with detailed diffusion and annihilation modeling across cosmic epochs, using expressions like the domain radius R = (N/n)^{1/3} and the antibaryon-photon ratio eta. Key results include mass and size constraints for surviving domains, estimates of boundary annihilation processes, and photon penetration depths that are typically boundary-localized during the radiation era; the work also discusses how these dynamics influence the domain's internal chemistry and potential observable signatures. The findings have implications for interpreting potential antimatter signatures in cosmic rays and guide future work on time-evolving domain structure and the conditions under which a homogeneous antimatter region could form or persist.
Abstract
According to modern physics, our Universe is baryon-asymmetric. That phenomenon can not be described in the frameworks of the Standard Model of particle physics. Globally, the Universe consists of baryon matter. However, some scenarios can lead to the existence of local antimatter domains. In the research, the chemical evolution of such an isolated antimatter domain, surrounded by baryonic matter, is studied. The size of the domain is estimated according to the conditions of its survival in baryon surrounding, and the process of annihilation at its border is taken into account.