Bulletin of the American Physical Society
80th Annual Meeting of the APS Southeastern Section
Volume 58, Number 17
Wednesday–Saturday, November 20–23, 2013; Bowling Green, Kentucky
Session CD: Nuclear Physics II |
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Chair: Christine Nattrass, University of Tennessee, Knoxville Room: 5 |
Thursday, November 21, 2013 11:00AM - 11:12AM |
CD.00001: ABSTRACT WITHDRAWN |
Thursday, November 21, 2013 11:12AM - 11:24AM |
CD.00002: Radioisotopic Batteries at Various Sizes beyond the Appraised Betavoltaic Cell Eric Steinfelds, Keith Andrew There several design concepts for radioisotopic batteries (aka nuclear batteries) besides Radioisotope Thermoelectric Generators (RTGs). In this SESAPS meeting, we shall introduce to physicists the very promising power alternative of a multi-decade radioisotopic battery -- to fit at mm and at microscales. We shall introduce the concept of Photon Assisted Radioisotope Energy Source (PARES) and more specifically to a solid state elaboration of PARES. Although RTGs have been constructed and effectively used to power mid-sized space probes for two generations, RTGs suffer from low efficiencies when made compact. An alternative to the RTG for small systems has been betavoltaic cells. A theoretical advantage of a betavoltaic cell over an RTG is that the betavoltaic uses quantum mechanical rather than thermodynamic mechanisms internally. However, in realistic devices we cannot totally escape the consequences of radiative exposure of crystalline components of solid betavolaic cells (most are solid) by beta particles. One of the solid state PARESes can be designed to be just as small as a betavoltaic cell, while continuing to perform well in the long term due to thorough and effective addressing of dose issues and appropriate internal shielding. [Preview Abstract] |
Thursday, November 21, 2013 11:24AM - 11:36AM |
CD.00003: An approach of relativistic mean field plus exact pairing for open-shell nuclei Wei-Chia Chen, Jorge Piekarewicz, Alexander Volya Pairing plays a crucial role in determining numerous properties of open-shell nuclei. Conventionally, it is included in the mean-field description of atomic nuclei through the approximate BCS or HFB formalism. In this work we propose a new hybrid approach to compute open-shell nuclei. We describe atomic nuclei using relativistic mean field theory. The mean fields are improved by taking pairing into account via the method of exact pairing in which pairing is treated in an exact way, and hence, number of particles is conserved. To verify its applicability, we use it to study the effect of pairing on properties of Sn isotopes (A=100-132), in particular their giant monopole resonances. Our results, such as the odd-even staggering of neutron separation energy and the trend of giant monopole energies along the isotopic chain, are consistent with experimental results. We also find that pairing has very small effect on the giant monopole energies, as what previous studies concluded. All in all, this approach provides another way to compute open-shell nuclei, and its usefulness is justified in the calculations for Sn isotopes. However, the problem of why Sn isotopes are so soft remains open, and to resolve it physics other than pairing seems necessary. [Preview Abstract] |
Thursday, November 21, 2013 11:36AM - 11:48AM |
CD.00004: Self Organizing Maps for Extracting Deep Inelastic Scattering Observables Evan Askanazi, Simonetta Liuti, Katherine Holcomb In Deep Inelastic Scattering, or DIS, the scattering cross section for proton-electron scattering and deuteron -electron scattering can be separated into a component that can be solved by perturbative QCD, or a ``hard'' section, and a component that can only be determined by scattering experiments, the ``soft'' section. The ``soft'' part of the scattering cross section, $F_{2}^{P}$ for an electron scattering off of a Proton and $F_{2}^{D}$ for an electron scattering off of a Deuteron, can be written as $\Sigma e_{i} q(x,Q^{2})$ where $q(x,Q^{2})$ is the Parton Distribution Function, or PDF, for each type of Parton that comprises the Proton or Deuteron and $\Sigma e_{i}$ is the charge of each proton type. The individual pdfs can only be parameterized based on fits to experimental data. A number of different collaborations, including CTEQ, MRST, GRV and MSTW, have attempted to parameterize the pdfs. We attempt to use the Self Organized Map to form our own parameterization of the pdfs, thereby allowing us to formulate a theoretical model for the soft part of the DIS cross section. The SOM is an Artificial Neural Network that uses unsupervised learning, which is a method of neural network learning molding an initial data set to a final data set without using the final set. [Preview Abstract] |
Thursday, November 21, 2013 11:48AM - 12:00PM |
CD.00005: Transverse momentum and pseudorapidity dependence of charged particle production and nuclear modification factor in pPb collisions at sqrt(sNN)=5.02 TeV with CMS Eric Appelt The charged particle transverse momentum (pT) spectra at midrapidity and forward pseudorapidity ranges up to pT=100 GeV/c are presented for pPb collisions at sqrt(sNN)=5.02 TeV. The nuclear modification factor (RpPb) is measured at midrapidity by dividing the measured pPb spectrum by a pp reference spectrum constructed using interpolation methods. In addition, the asymmetries in the charge particle yields between equivalent positive and negative pseudorapidity ranges in both the laboratory and center-of-mass frames are presented as a function of pT. [Preview Abstract] |
Thursday, November 21, 2013 12:00PM - 12:12PM |
CD.00006: Generalised Transverse Momentum Distributions FNU Abha Rajan Thirty years after the discovery of the EMC effect, the missing source of the proton spin continues to baffle the scientific community. Analysis of other contributing factors such as quark and gluon orbital orbital angular momentum is the key to a clearer understanding of the problem. Wigner distributions are density distributions that give simultaneous description in momentum transfer and transverse spatial separation. We study how generalised transverse momentum distributions, (purely momentum space counterparts of wigner distributions) that are expected to describe the orbital angular momentum of partons in the nucleon, can enter the deeply virtual compton scattering amplitude only through matrix elements involving a final state interaction. With a clearer understanding of the order of twist of these distributions, we will have access to the much sought after observables related to partonic orbital angular momentum. [Preview Abstract] |
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