Bulletin of the American Physical Society
77th Annual Meeting of the Southeastern Section of the APS
Volume 55, Number 10
Wednesday–Saturday, October 20–23, 2010; Baton Rouge, Louisiana
Session CD: Nuclear Physics, Mesons, and Quantum Gravity |
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Chair: Romulus Godang, University of South Alabama Room: Nicholson Hall 108 |
Thursday, October 21, 2010 10:45AM - 10:57AM |
CD.00001: The $\beta$ decay studies of $^{75}$Cu using LeRIBSS S. Ilyushkin, J. Winger, K. Rykaczewski, C. Gross, J. Batchelder, L. Cartegni, I. Darby, R. Grzywacz, J. Hamilton, A. Korgul, W. Krolas, S. Liddick, C. Mazzocchi, S. Padgett, A. Piechaczek, M. Rajabali, D. Shapira, E. Zganjar The $\beta$ decay of $^{75}$Cu ($t_{1/2}=1.222(8)\,$s) to levels in $^{75}$Zn has been studied at the Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory. The $\gamma\gamma$ and $\beta\gamma$ data were collected using the Low-energy Radioactive Ion Beam Spectroscopy Station making use of the high-resolution isobar separator. This resulted in considerable information on the previously unknown level structure of $^{75}$Zn with some 120 $\gamma$-ray transitions placed in a level scheme containing 59 levels including two states above the neutron separation energy. A previously unknown $1/2^-$ isomeric state at 127 keV is proposed. In addition, spins and parities of several states are proposed based on the observed decay pattern. These states can be explained in terms of coupling neutrons in the $1g_{9/2}$ and $2p_{1/2}$ orbitals to protons in the $1g_{5/2}$ and $2p_{3/2}$ orbitals. Results of $\beta$ decay studies of $^{75}$Cu will be presented. [Preview Abstract] |
Thursday, October 21, 2010 10:57AM - 11:09AM |
CD.00002: The Array for Nuclear Astrophysics Studies with Exotic Nuclei L.E. Linhardt, J.C. Blackmon, M. Matos, L.L. Mondello, E.F. Zganjar, E. Johnson, G. Rogachev, I. Wiedenhover The Array for Nuclear Astrophysics Studies with Exotic Nuclei (ANASEN) is a charged-particle detector array that is targeted primarily towards reaction studies with radioactive ion beams at FSU and the NSCL. ANASEN consists of 40 double-sided silicon-strip detectors backed with CsI scintillators and an innovative gas counter design that allows operation in a gas target/detector mode and experiments covering a broad range of center-of-mass energies simultaneously. Electronics based on ASIC components are being implemented to achieve a high channel count at low cost. Prototypes of all the detector components have been fabricated and are currently being tested. Performance of the individual components and plans for the first experiments that aim to improve our knowledge of the nuclear reactions important in stellar explosions will be reported. [Preview Abstract] |
Thursday, October 21, 2010 11:09AM - 11:21AM |
CD.00003: Use of Hulthen potential in Light-Front Two-Body Bound-State problem Yukihisa Tokunaga Solving the relativistic bound-state problem is an important task in nuclear physics. Even the two-body bound-state problem has been solved only under a certain approximation due to the nonperturbative nature. The two-body Bethe-Salpeter equation in the Wick-Cutkosky model was often solved in the ladder approximation without including the cross-ladder contribution, although many different and more accurate treatments of the numerical method to solve the bound-state problem have been developed nowadays. In this presentation, we use the exact solution to Hulthen potential as a trial wave function to solve the two-body bound-state problem based on the variational principle. We extend the light-front ladder approximation to include the cross-ladder contribution and present the numerical result of the binding energy versus the coupling constant including the particle and antiparticle effect to the cross-ladder contribution. In particular, we discuss the case with the exchange particle of non-zero mass to compare the effect in the Coulomb potential vs. the Yukawa potential. We show the effectiveness of our new trial wave function in variational method based on the Hulthen potential and further explain the individual contribution from the cross-ladder and the stretched-box. [Preview Abstract] |
Thursday, October 21, 2010 11:21AM - 11:33AM |
CD.00004: High Energy Pion Photoproduction from Nucleons in the Giessen Bolzmann-Uehling-Uhlenbeck Model Prajwal Mohanmurthy For long, the transitions between perturbative and nonperturbative regimes of QCD have been of interest in nuclear physics. One of the methods used to study these transitions is to look for the onset of predictive QCD laws such as the quark counting rule. Measuring the differential cross section of certain exclusive reactions (such as pion photo production) has been one of the prime methods of investigating quark counting rules. The CEBAF Large Acceptance Spectrometer (CLAS) in Hall B at the Jefferson Lab (JLAB) has been used to measure the cross sections of pion photo production reactions. These measurements can be used to better understand the scaling laws. Although the cross-section does show scaling behavior, the onset of scaling is at unusually low energies and an unexplained sharp drop in the cross-section is observed just before the onset of scaling. There is a lack of theoretical calculations of pion photo production cross-section at these energies. The model known as the Giessen Boltzmann-Uehling-Uhlenback (GiBUU) model has been used to calculate the pion photo-production cross-section and it was compared with the CLAS measurements. The preliminary results shall be presented. [Preview Abstract] |
Thursday, October 21, 2010 11:33AM - 11:45AM |
CD.00005: Relativistic Studies of the Charmonium and Bottomonium Meson Systems Using the Sucher Equation Charles Werneth, Khin Maung Maung The bound states of quarks and anti-quarks (mesons) are studied with a relativistic equation known as the Sucher equation. Prior to this research, meson mass spectra had not been studied with the Sucher equation. Moreover, a full angular momentum analysis of the Sucher equation had not been investigated. The Sucher equation is equivalent to the Schr\"{o}dinger equation with relativistic kinematics and a spin-dependent effective potential. Through a complete general angular momentum analysis, we find that angular momenta can couple through the effective potential without explicitly including the tensor interaction. We predict the charmonium and bottomonium mass spectra using the Sucher equation. We find that the Sucher equation may be used for the charmonium and bottomonium meson systems, but the inherent spin-dependent effective potential fails to produce the proper energy level splitting between singlet and triplet states. [Preview Abstract] |
Thursday, October 21, 2010 11:45AM - 11:57AM |
CD.00006: Exploring the Use of the Alabama Supercomputing Authority resources to supplement CMS Monte Carlo Production Charles Jenkins The 14 TeV center of mass proton-proton collisions of the LHC is designed to search for the Higgs, but opens the possibility for observing new Physics including SUSY, quark compositeness and large extra dimension if these phenomenon exists. The analysis of data collected from CMS will rely on the generation of extensive number of monte carlo events. Currently, a faculty member at the University of South Alabama is studying the possibility of utilizing one of the Alabama Supercomputer Center (ASC) computer clusters to help the CMS monte carlo group in generating events. This investigation is in the early phase, but the researcher has generated a sample of events for the CMS monte carlo test example channel H(190)$\to $Z$^{0}$Z$^{0}\to \mu ^{+}\mu ^{-}\mu ^{+}\mu ^{-}$ on both the Dense Memory Core cluster at the ASC and a similar sample on a PC running Scientific Linux 5.4. A description of how the CMS analysis software is implemented on the Alabama Supercomputer DMC cluster will be presented. The distribution from the test samples from both machines will be presented and compared. [Preview Abstract] |
Thursday, October 21, 2010 11:57AM - 12:09PM |
CD.00007: Towards generic resolution of strong singularities in loop quantum cosmology Parampreet Singh Singularities are the boundaries of classical spacetime in General Relativity. It has been always hoped that quantum gravitational effects may resolve these singularities. In recent years, progress in loop quantum cosmology has provided insights on the resolution of big bang, big crunch and other spacelike singularities. In this talk we will give an update on the recent status of the generic resolution of strong spacelike singularities in loop quantum cosmology. We will show that for flat and curved Roberston-Walker backgrounds and also for Bianchi-I models, loop quantum gravity effects resolve all strong curvature singularities. However, weak curvature singularities, that is those beyond which geodesics can be continued, may not be resolved. [Preview Abstract] |
Thursday, October 21, 2010 12:09PM - 12:21PM |
CD.00008: Characterization of pixilated Cadmium-Zinc-Telluride (CZT) Detector Sensitivity for Future Neutrinoless Double Beta (0$\nu \beta \beta )$ Decay Searches Kevin Macon, Alexander Leder, Jun Miyamoto, Thomas Kutter The detection of 0$\nu \beta \beta $ decay provides an opportunity to determine whether neutrinos are Majorana or Dirac particles. Detecting 0$\nu \beta \beta $ decay requires very sensitive detectors with good energy resolution. Pixelization in CZT detectors promises to improve sensitivity by means of improving background rejection. Our studies focused on the response of a pixilated prototype CZT detector to evaluate improvements in sensitivity. We performed energy resolution measurements for a 16 pixel CZT detector in the 100keV to 1.3 MeV range. Common background sources were simulated and the measured energy resolutions were then incorporated to estimate detector sensitivities for a potential 0$\nu \beta \beta $ Cd-116 decay signal. In this talk we present the status of our research, preliminary results and offer an outlook on future work and challenges. [Preview Abstract] |
Thursday, October 21, 2010 12:21PM - 12:33PM |
CD.00009: Studies of Bulk Properties of CZT and CMT Crystals for X-Ray and Gamma-Ray Detection at Ambient Temperature S.U. Egarievwe, A.E. Bolotnikov, U.N. Roy, S.O. Babalola, A. Kassu, J. Jow, G. Camarda, P. Fochuk, W. Chan, K.H. Kim, J. Stein, R.B. James, A. Burger Cadmium Zinc Telluride (CZT) and Cadmium Manganese Telluride (CMT) crystals have emerged as promising advanced materials for X-ray and gamma-ray detection at ambient temperature. An understanding of the bulk properties in relation to energy resolution and device performance has led to the development of CZT into commercial devices, and is contributing to the improvement of CMT. The key detector attributes are large band-gap energy ($\sim $1.6 eV, tunable by Zn or Mn concentration), high atomic number, and high density ($\sim $6 g/cm$^{3})$. The techniques used in this study include infrared transmission microscopy, synchrotron X-ray diffraction topography, micro-scale X-ray mapping, and Pockels effect. We found that point defects and Te inclusions in CZT and CMT can trap the charge carriers generated by the absorption of X-rays, gamma-rays, and charged particles. We propose the use of thermal annealing and doping techniques to eliminate the deleterious effects caused by Te inclusions. [Preview Abstract] |
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