Bulletin of the American Physical Society
2012 Fall Meeting of the APS Division of Nuclear Physics
Volume 57, Number 9
Wednesday–Saturday, October 24–27, 2012; Newport Beach, California
Session DG: Nuclear Theory II |
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Chair: Ian Thompson, Lawrence Livermore National Laboratory Room: Surf |
Thursday, October 25, 2012 10:30AM - 10:42AM |
DG.00001: A Relativistic Multiple Scattering Theory for Nucleus-Nucleus Collisions with Delta Resonance Coupling Charles Werneth, Khin Maung Maung, John Norbury Non-relativistic multiple scattering theories (NRMST) are formulated by separating the unperturbed Hamiltonian from the interaction and writing the Lippmann-Schwinger equation as an infinite series in the multiple sums of pseudo two-body operators, known as the Watson tau-operators. The advantage of using the multiple scattering theory (MST) is that the pseudo two-body operators are often well approximated by free two-body nucleon-nucleon operators, which are obtained from parameterizations of experimental data. Relativistic theories are needed to properly describe the production of new particles, such as pions, from nucleus-nucleus collisions. Relativistic multiple scattering theories (RMST) have been developed for nucleon-nucleus scattering; however, no RMST for nucleus-nucleus scattering has yet been derived.\footnote{Maung K M, Norbury J W, and Coleman T 2007 \textit{J. Phys.} G \textbf{34} 1861.} The purpose of this research is to derive an RMST for nucleus-nucleus scattering and to include delta degrees of freedom in the interaction, the minimum requirement for pion production. [Preview Abstract] |
Thursday, October 25, 2012 10:42AM - 10:54AM |
DG.00002: $\Delta$ Isobar Degrees of Freedom in the $^3$He Transverse (e,e') Response Function Edward Tomusiak, Luping Yuan, Winfried Leidemann, Victor Efros, Giuseppina Orlandini The $^3$He transverse electron scattering response function $R_T(q,\omega)$ is calculated in the quasi-elastic peak region and beyond for momentum transfers $q \ge$ 500 MeV/c. In addition to $\Delta$-isobar currents ($\Delta$-IC) we include meson exchange currents and relativistic corrections to one-body currents. The calculation is performed using the AV18-NN potential and the UrbanaIX three-nucleon force. The $\Delta$-IC are calculated in impulse approximation using the Lorentz integral transform (LIT) method (details are given in Ref. [1] and references therein). In addition to results for $q$=500, 600, and 700 MeV/c we plan to present results at even higher $q$. Use of the Active Nucleon Breit frame together with the two-fragment kinematical model results in excellent agreement with experiment in the quasi-elastic peak region. In addition our results suggest the importance of $\Delta$-IC for three-body break-up reactions in the dip region. \\[4pt] [1] L. Yuan, V.D. Efros, W. Leidemann, G. Orlandini, and E.L. Tomusiak, Phys. Rev. {\bf C72}, 011002(R) (2005) [Preview Abstract] |
Thursday, October 25, 2012 10:54AM - 11:06AM |
DG.00003: New Developments on Target Mass Corrections Matthew Brown, Wally Melnitchouk We consider the consistency of factorization of deep-inelastic nucleon structure functions in the presence of target mass corrections (TMCs) at low $Q^{2}$. After reviewing the standard operator product expansion derivation of TMCs in both $x$- and moment-space, we compare the results with those based on collinear factorization and assess their convergence. We discuss the limitations of the various TMC prescriptions, including attempts to alleviate the threshold problem for the behavior of structure functions as $x\to $ 1. The results are used to analyze recent high-precision structure function data from experiments at Jefferson Lab. [Preview Abstract] |
Thursday, October 25, 2012 11:06AM - 11:18AM |
DG.00004: Light-front holography and the coupled-cluster method John Hiller We explore a combination of light-front holographic QCD and the light-front coupled-cluster (LFCC) method in the context of a quark model for mesons. The LFCC method converts the meson eigenstate problem of QCD into an effective eigenproblem in the valence quark-antiquark Fock sector. Light-front holography then provides an analytically solvable model for the valence sector, which can be used as a starting point for the solution of the LFCC eigenproblem. [Preview Abstract] |
Thursday, October 25, 2012 11:18AM - 11:30AM |
DG.00005: The light-front coupled-cluster approach to scalar theories with and without symmetry breaking Sophia Chabysheva The light-front coupled-cluster method is applied to various two-dimensional scalar theories, including wrong-sign $\phi^4$ theory. This tests the utility of the method in the detection of spontaneous symmetry breaking, an important precursor to a nonperturbative formulation of the Higgs mechanism. [Preview Abstract] |
Thursday, October 25, 2012 11:30AM - 11:42AM |
DG.00006: Coupled-channel systems in a finite volume Zohreh Davoudi In this talk I will motivate studies of two-body coupled-channel systems in a finite volume in connection with the ultimate goal of studying nuclear reactions, as well as hadronic resonances, directly from lattice QCD. I will discuss how one can determine phase shifts and mixing parameters of coupled-channels such as that of pipi-KK isosinglet system from the energy spectrum in a finite volume with periodic boundary conditions. From the energy quantization condition, the volume dependence of electroweak matrix elements of two-hadron processes can also be extracted. This is necessary for studying weak processes that mix isosinglet-isotriplet two-nucleon states, e.g. proton-proton fusion. I will show how one can obtain such transition amplitudes from lattice QCD using the formalism developed. [Preview Abstract] |
Thursday, October 25, 2012 11:42AM - 11:54AM |
DG.00007: Quark Synthesis String Theory From Dark Matter to Light Emitting Atoms William Webb Forefather physicists formulated fusion based on nucleosynthesis. They directed that whole nucleons synthesize. Quark Synthesis String Theory now shows that \emph{it's the string-like quarks that do the synthesizing: not whole nucleons}. In a dark region, string-like quarks synthesize with other string-like quarks to make rope-like quarks. Quarks structure into threesomes bound only by electrostatic and gravitational forces. Quarks not structuring as threesomes remain dark. Balanced threesomes of string-like quarks become neutrons. Balanced threesomes of rope-like quarks become more massive neutroniumA nuclei. After their formation, neutrons and neutroniumAs quickly begin emitting electrons. This paper develops equations that correctly describe nuclear structures and their electron emissions. Electron emission beta decay is calculated for the 30 least massive neutroniumA nuclei and their subsequent transmutation thru 203 intermediate nuclei on their way to becoming well known nuclei centering the 30 least massive light emitting atoms. This is a perfect 233 for 233 match between calculations of Quark Synthesis String Theory and factual nuclear data. This perfect match provides affirmation that nuclei have no need for the unknown strong or week forces and mediating particles. Nuclear physics succeeds using a string theory that has the quarks doing the synthesizing. [Preview Abstract] |
Thursday, October 25, 2012 11:54AM - 12:06PM |
DG.00008: Towards Nuclear Reactions from Lattice QCD Raul Briceno In this talk I will motivate the evaluation of nuclear reactions cross sections from Lattice Quantum Chromodynamics (LQCD) and discuss challenges associated with such calculations. In particular, I will explore the connection between the energy spectrum of a three-body system in a finite volume and infinite volume scattering matrix elements using an effective field theoretical approach. The implication of this formalism for studying systems composed of a particle and a bound-state below the bound-state break- up, as well as a trimer state will be discussed. I will show that one in fact recovers a Luscher-like quantization condition for sufficiently low-energy up to exponential corrections in the volume due to the size of the two-particle bound-state. I will briefly discuss the similarities of the three-body problem and that of two- body coupled-channels systems and will comment on challenges in applying the formalism above the inelastic threshold. [Preview Abstract] |
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