Johann Rafelski

We present state-of-the-art kinetic theory determination of the neutron abundance available for the Big-Bang nucleosynthesis (BBN). This paper is motivated by the study of the neutron lifespan measured in the laboratory and the unknown strength of weak interactions coupling constant $G_{\mathrm{F}}$ at finite temperature in the primordial Universe. We draw attention to the relevant dependence of $G_{\mathrm{F}}$ on the symmetry breaking Weinberg angle $s_{\mathrm{W}}^2$, which is a free parameter in the standard model of particle physics. We establish how the value of $s_{\mathrm{W}}^2$ by way of $G_{\mathrm{F}}$ modification influences the neutron abundance available for BBN and neutron lifetime.

We explore the Higgs particle in the cosmic quark-gluon plasma (QGP) below the electroweak phase transition temperature $T_\mathrm{EW}\simeq 125\mathrm{\,GeV}$. We show that Higgs is neither in abundance (chemical) nor in momentum distribution equilibrium in certain stages of the Universe evolution. Nonequilibrium originates in: For chemical nonequilibrium in the always present irreversible decays into virtual heavy gauge bosons, and; For $T<25$\,GeV in relatively rapid $2\leftrightarrow 1$ formation and decay processes yielding momentum distribution as created in these reactions. As heavy particles disappear, the minimal Higgs coupling to abundant low mass particles fails in $2\to2$ (two-particle) scattering processes to assure a kinetic distribution equilibrium. The expansion of the Universe is by more than 10 orders of magnitude slower compared to microscopic processes. All other particles in the Universe are in full thermal equilibrium, with exception of the late in QGP evolution of the bottom flavor near to hadronization condition.

We describe in the context of the particle physics (PP) standard model (SM) ‘PP-SM’ the understanding of the primordial properties and composition of the Universe in the temperature range $$130\,\textrm{GeV}>T>20\,\textrm{keV}$$ 130 GeV > T > 20 keV . The Universe evolution is described using FLRW cosmology. We present a global view on particle content across time and describe the different evolution eras using deceleration parameter q . In the considered temperature range the unknown cold dark matter and dark energy content of $$\varLambda \textrm{CDM}$$ Λ CDM have a negligible influence allowing a reliable understanding of physical properties of the Universe based on PP-SM energy–momentum alone. We follow the arrow of time in the expanding and cooling Universe: After the PP-SM heavies ( t , h , W , Z ) diminish in abundance below $$T\simeq 50\,\textrm{GeV}$$ T ≃ 50 GeV , the PP-SM plasma in the Universe is governed by the strongly interacting Quark-Gluon content. Once the temperature drops below $$T\simeq 150\,\textrm{MeV}$$ T ≃ 150 MeV , quarks and gluons hadronize into strongly interacting matter particles comprising a dense baryon-antibaryon content. Rapid disappearance of baryonic antimatter ensues, which adopting the present day photon-to-baryon ratio completes at $$T_\textrm{B}=38.2\,\textrm{MeV}$$ T B = 38.2 MeV . We study the ensuing disappearance of strangeness and mesons in general. We show that the different eras defined by particle populations are barely separated from each other with abundance of muons fading out just prior to $$T=\mathcal {O}(2.5)\,\textrm{MeV}$$ T = O ( 2.5 ) MeV , the era of emergence of the free-streaming neutrinos. We develop methods allowing the study of the ensuing speed of the Universe expansion as a function of fundamental coupling parameters in the primordial epoch. We discuss the two relevant fundamental constants controlling the decoupling of neutrinos. We subsequently follow the primordial Universe as it passes through the hot dense electron-positron plasma epoch. The high density of positron antimatter disappears near $$T=20.3\,\textrm{keV}$$ T = 20.3 keV , well after the Big-Bang Nucleosynthesis era: Nuclear reactions occur in the presence of a highly mobile and relatively strongly interacting electron-positron plasma phase. We apply plasma theory methods to describe the strong screening effects between heavy dust particle (nucleons). We analyze the paramagnetic characteristics of the electron-positron plasma when exposed to an external primordial magnetic field.

We seek to understand the effect of high electron density in the proximity of a heavy nucleus on the fusion reaction rates in a hot plasma phase. We investigate quantitatively the catalytic effect of gold ( $$Z=79$$ Z = 79 ) ions embedded in an electron plasma created due to plasmonic focusing of high-intensity short laser pulses. Using self-consistent strong plasma screening, we find highly significant changes in the inter-nuclear potential of light elements present nearby. For gold, we see a $$14\,$$ 14 keV change in the inter-nuclear potential near the nuclear surface, independent of the long-distance thermal Debye–Hückel screening. The dense polarization cloud of electrons around the gold catalyst leads to a $$\sim 1.5$$ ∼ 1.5 enhancement of proton–boron ( $$^{11}$$ 11 B) fusion near $$T=100$$ T = 100 keV.

We explore the Higgs particle in the cosmic quark-gluon plasma (QGP) below the electroweak phase transition temperature $T_\mathrm{EW}\simeq 125\mathrm{\,GeV}$. We show that Higgs is neither in abundance (chemical) nor in momentum distribution equilibrium in certain stages of the Universe evolution. Nonequilibrium originates in: For chemical nonequilibrium in the always present irreversible decays into virtual heavy gauge bosons, and; For $T<25$\,GeV in relatively rapid $2\leftrightarrow 1$ formation and decay processes yielding momentum distribution as created in these reactions. As heavy particles disappear, the minimal Higgs coupling to abundant low mass particles fails in $2\to2$ (two-particle) scattering processes to assure a kinetic distribution equilibrium. The expansion of the Universe is by more than 10 orders of magnitude slower compared to microscopic processes. All other particles in the Universe are in full thermal equilibrium, with exception of the late in QGP evolution of the bottom flavor near to hadronization condition.