1. Physics Colloquium

    "Journey in time through the universe from a visit to the quark-gluon plasma era"

    Presented by Johann Rafelski, University of Arizona at Tuscon

    Tuesday, January 21, 2014, 1:30 pm
    Large Seminar Room, Bldg. 510

    Hosted by: Andrei Nomerotski

    Matter surrounding us arose from the primordial phase of matter, Quark-Gluon Plasma (QGP). QGP was omni-present up to when the Universe was 13 microseconds old, just the time it takes for heavy ions to travel around the BNL-RHIC ring. As the universe expands and cools QGP hadronizes, forming abundant matter and antimatter. Only a nano-fraction surplus of nuclear matter survives annihilation process. A dense electron-positron-photon-neutrino plasma remains. The description of neutrino chemical and kinetic freeze-out dynamics requires use of the methods we developed in study of hadron freeze-out in QGP hadronization. Electrons and positrons begin to annihilate nearly at the same time when neutrinos decouple. Electron-positron-annihilation process lasts through the big-bang nucleo-synthesis (BBN) period. In the background of free streaming dark matter and neutrino fluids the visible matter evolves till ion-electron recombination completes, and the Universe becomes transparent to free-steaming light we observe as the cosmic microwave background.