Bulletin of the American Physical Society
75th Annual Meeting of the Southeastern Section of APS
Volume 53, Number 13
Thursday–Saturday, October 30–November 1 2008; Raleigh, North Carolina
Session BA: Forefront Nuclear Physics |
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Chair: Paul Cottle, Florida State University Room: Holiday Inn Brownstone Roosevelt |
Thursday, October 30, 2008 8:30AM - 9:00AM |
BA.00001: The Nature of the Quark-Gluon-Plasma Invited Speaker: The Quark-Gluon-Plasma (QGP) is a highly excited, strongly interacting, hot and dense state of matter. Its degrees of freedom are quarks and gluons which are the basic constituents of quantum chromodynamics (QCD), one of the four fundamental forces of nature. It is believed that shortly after the creation of the universe in the Big Bang all matter was in the QGP state. Due to the rapid expansion and cooling of the Universe, this plasma underwent a transition to form hadrons (bound states of quarks and gluons), which constitute the building blocks of matter as we know it today. The investigation of QGP properties and the nature of the QGP to hadron transition will yield important novel insights into the development of the early universe and the behavior of QCD under extreme conditions. More than a thousand experimentalists are working to recreate this highly excited state of primordial matter under controlled laboratory conditions by colliding two heavy atomic nuclei at relativistic energies and to study its properties. These experiments are currently underway at the Relativistic Heavy-Ion Collider (RHIC) at Brookhaven National Laboratory. Data from the first years of RHIC operations have yielded many interesting and sometimes surprising results which have not yet been fully evaluated or understood. In my talk I will highlight some of the most exciting discoveries made at RHIC and discuss recent theoretical efforts to understand the nature and properties of the QGP created there. [Preview Abstract] |
Thursday, October 30, 2008 9:00AM - 9:30AM |
BA.00002: Fundamental symmetry tests with ultracold neutrons Invited Speaker: Ultracold neutrons (UCN) are neutrons with kinetic energies so low (less than 200--300 nano-eV) that they can be ``bottled'' with material surfaces or magnetic fields of a few Tesla. In this talk I will discuss the application of UCN to high-precision tests of the fundamental symmetries underlying the standard electroweak theory. I will highlight ongoing experiments and also provide a preview of future physics opportunities utilizing UCN in the Southeast, particularly those to be staged at the Spallation Neutron Source. [Preview Abstract] |
Thursday, October 30, 2008 9:30AM - 10:00AM |
BA.00003: Neutrino oscillations: what do we know about $\theta_{13}$ Invited Speaker: The phenomenon of neutrino oscillations is reviewed. A new analysis tool for the recent, more finely binned Super-K atmospheric data is outlined. This analysis incorporates the full three-neutrino oscillation probabilities, including the mixing angle $\theta_{13}$ to all orders, and a full three- neutrino treatment of the Earth's MSW effect. Combined with the K2K, MINOS, and CHOOZ data, the upper bound on $\theta_{13}$ is found to arise from the Super-K atmospheric data, while the lower bound arises from CHOOZ. This is caused by the linear in $\theta_{13}$ terms which are of particualr importance in the region $L/E>10^4$ m/MeV where the sub-dominant expansion is not convergent. In addition, the enhancement of $\theta_{12}$ by the Earth MSW effect is found to be important for this result. The best fit value of $\theta_{13}$ is found to be (statistically insignificantly) negative and given by $\theta_{13}=-0.07^{+0.18}_{-0.11}$. In collaboration with Jesus Escamilla, Vanderbilt University and David Latimer, University of Kentucky. [Preview Abstract] |
Thursday, October 30, 2008 10:00AM - 10:30AM |
BA.00004: A New ECR Ion Source for Nuclear Astrophysics Studies Invited Speaker: The Laboratory for Experimental Nuclear Astrophysics (LENA) is a low energy facility designed to study nuclear reactions of astrophysical interest at energies which are important for nucleosysthesis. In general, these reactions have extremely small cross sections, requiring intense beams and efficient detection systems. Recently, a new, high intensity electron-cyclotron-resonance (ECR) ion source has been constructed (based on a design by Wills et al.[1]), which represents a substantial improvement in the capabilities of LENA. Beam is extracted from an ECR plasma excited at 2.45 GHz and confined by an array of permanent magnets. It has produced H$^{+}$ beams in excess of 1 mA on target over the energy range 100 - 200 keV, which greatly increases our ability to measure small cross sections. Initial measurements will focus on the $^{23}$Na(p,$\gamma$)$^{24}$Mg reaction, which is of interest in a variety of astrophysical scenarios. The present uncertainty in the rate of this reaction is the result of an unobserved resonance expected at E$_{lab}$ =144 keV, which should be detectable using beams from the new ECR source. In collaboration with Arthur E. Champagne and Thomas B. Clegg, University of North Carolina, Chapel Hill and TUNL. \\[3pt] [1] J. S. C. Wills {\em et al.}, Rev. Sci. Instrum. \textbf{69}, 65 (1999). [Preview Abstract] |
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