Reactions Governing Strangeness Abundance in Primordial Universe

Abstract

Strangness production processes can balance natural strangeness decay in the early hadronic Universe. Comparing to the characteristic Hubble time $1/H$, the reaction rates for ${\mu }^{\pm }+{\nu }_{\mu }\to K^{\pm }$, $l^{-}+l^{+}\to \varphi$, and $\pi +\pi \to K$ in sequence become slower than expansion rate at $T=33.9\mathrm{MeV}$, $T=25\mathrm{MeV}$ and $T=20\mathrm{MeV}$ respectively. This means that in the antibaryon annihilation epoch near to $T\simeq 40\mathrm{MeV}$ strangeness is in chemical equilibrium.

Comments: 4 compact pages, 3 figures, Contribution to SQM2021 Online conference