Bulletin of the American Physical Society
2013 Fall Meeting of the APS Division of Nuclear Physics
Volume 58, Number 13
Wednesday–Saturday, October 23–26, 2013; Newport News, Virginia
Session HA: Quark Gluon Plasma, the Proton, and the Universe |
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Chair: Ani Aprahamian, University of Notre Dame Room: Grand Ballroom I |
Friday, October 25, 2013 8:30AM - 9:06AM |
HA.00001: Hot QCD Matter In and Out of Equilibrium Invited Speaker: Jinfeng Liao Relativistic heavy ion collision experiments at RHIC and LHC have found a hot dense QCD matter that is interacting very strongly both in and out of equilibrium. We argue that such strongly interacting nature arises when the typically well-separated scales in a weakly coupled thermal quark-gluon plasma (QGP) begin to ``collapse'' together. This happens in equilibrium when the coupling itself becomes strong, which is the case of the thermal QGP near QCD transition temperature. This also happens out-of-equilibrium when the phase space is maximally occupied even though the coupling is not large, which is the case of the pre-equilibrium dense gluon system (``glasma'') during the early stage of heavy ion collisions. We report progress on our understanding of both systems and discuss the important implications for the observed matter properties, such as the shear viscosity, color opaqueness, as well as as well as thermalization. In particularly we predict specific patterns for the evolution of these properties with collision energies from RHIC to LHC.\\[4pt] References: J. Blaizot, J. Liao and L. McLerran, arXiv:1305.2119; X. Huang and J. Liao, arXiv:1303.7214; J. Blaizot, F. Gelis, J. Liao, L. McLerran and R. Venugopalan, arXiv:1107.5296; J. Liao, arXiv:1109.0271; X. Zhang and J. Liao, arXiv: 1208.6361, 1210.1245, 1202.1047. [Preview Abstract] |
Friday, October 25, 2013 9:06AM - 9:42AM |
HA.00002: Investigating the charge of the proton Invited Speaker: Michael Kohl It has been known from the beginnings of electron scattering that the electric charge of the proton is not pointlike. The elastic form factors characterize the distributions of charge and magnetization in momentum space and are important input for calculations of strong interaction phenomena and nuclear structure. With improvements in experimental techniques and higher precision, data have shown inconsistencies when analyzed in the single-photon exchange approximation, generating a large uncertainty particularly for the proton charge form factor at high momentum transfer. Previously neglected higher-order radiative corrections have been favored for an explanation. To quantify the role of two-photon exchange is the main purpose of the OLYMPUS experiment at DESY. In the static limit, the elastic charge form factor is related to the root-mean-square charge radius, which can also be determined from atomic hydrogen spectroscopy. Recent measurements of the proton charge radius from elastic electron scattering and from the Lamb shift in muonic hydrogen have generated the so-called proton radius puzzle. I will give an overview on the current data landscape and discuss present and future efforts to resolve the pending puzzles of the proton form factors and the proton charge radius. [Preview Abstract] |
Friday, October 25, 2013 9:42AM - 10:18AM |
HA.00003: In the beginning \ldots Invited Speaker: Johann Rafelski \ldots freely propagating quarks and gluons existed in the Universe in a deconfined phase of matter, the quark-gluon plasma (QGP). Relativistic heavy ion (RHI) experiments have established that the structure of matter changed when the Universe cooled to a temperature of about $T\simeq 150\,$MeV. At that time, about $20\,\mu$s after the Big Bang, mass-carrying hadrons and anti-hadrons formed. To explain the change in the form of matter that fills the Universe, confinement of the QCD charge, the color, in the `frozen' vacuum is required. This is confirmed by the decade-long dedicated RHI experimental effort in which hot drops of QGP were created and studied. Such a drastic temperature-dependent change in the transport properties of the vacuum is a paradigm change: the laws of physics are not only encoded in the vacuum, but are subject to modification as a function of temperature. QGP hadronization, the conversion of QGP into hadrons, produced matter and antimatter in laboratory. By applying hadronization to the early Universe we obtain the properties of the hot emergent nearly symmetric matter-antimatter Universe. After three seconds, all antimatter mixed into matter in the Universe is annihilated. Many questions remain open about the details of Universe hadronization and annihilation process, and its relation to the observed matter-antimatter asymmetry. [Preview Abstract] |
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