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SUMMARY:Primordial Nucleosynthesis in Hierarchical Antimatter Domains
DTSTART;VALUE=DATE-TIME:20261027T162500Z
DTEND;VALUE=DATE-TIME:20261027T163000Z
DTSTAMP;VALUE=DATE-TIME:20261024T054126Z
UID:indico-contribution-6460@cern.ch
DESCRIPTION:Speakers: Anna Dembitskaia (National Research Nuclear Universi
 ty MEPhI\, Moscow\, Russia)\nIn a baryon-asymmetric Universe\, primordial 
 antimatter domains arise from inhomogeneous baryogenesis driven by the Pse
 udo-Nambu-Goldstone Boson field during inflation. Their evolution is gover
 ned by the competition between Hubble expansion and microphysical erosion 
 of the domain boundary via annihilation with surrounding matter.\nThe doma
 in\, however\, is not homogeneous. Stochastic dynamics of the phase during
  inflation causes repeated recrossings of the potential barrier\, producin
 g a self-similar nested hierarchy: antimatter domains containing baryonic 
 inclusions\, which themselves contain antibaryonic inclusions\, and so on 
 down to the horizon scale at the end of inflation. \nThe key consequence f
 or nucleosynthesis is that annihilation proceeds throughout the volume\, n
 ot on a single outer boundary. At t =100 s\, free neutrons diffuse to the 
 internal interfaces and annihilate there\, suppressing primordial helium-4
 . High-energy photons from pion decay photodissociate helium-4 nuclei\, si
 gnificantly raising the helium-3 to helium-4 ratio\, while non-thermal rea
 ctions overproduce lithium-6. This provides a unique chemical signature fo
 r antimatter astrophysical objects such as anti-stars or globular clusters
 . On the other side nonhomogeneity of antimatter domain facilitates format
 ion of antimatter objects of stellar mass\, which can be source of antihel
 ium-4 in cosmic rays.\nCurrent models predict an anti-helium flux within r
 each of the AMS-02 experiment. Consistency with cosmic microwave backgroun
 d and diffuse gamma-ray observations sets a strict upper limit on the frac
 tion of annihilated antimatter\, imposing strong constraints on models of 
 inhomogeneous baryogenesis.\n\nhttps://indico.particle.mephi.ru/event/626/
 contributions/6460/
LOCATION:Sevastopol hotel Conference Hall 1
URL:https://indico.particle.mephi.ru/event/626/contributions/6460/
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