Bulletin of the American Physical Society
2017 Fall Meeting of the APS Division of Nuclear Physics
Volume 62, Number 11
Wednesday–Saturday, October 25–28, 2017; Pittsburgh, Pennsylvania
Session NB: Nuclear Reactions: Hadrons/Light Ions |
Hide Abstracts |
Chair: Sean Kuvin, University of Connecticut Room: Salon 2 |
Saturday, October 28, 2017 8:30AM - 8:42AM |
NB.00001: $^6$Li and $d+\alpha$ scattering in a three-body momentum space Faddeev model (I) Lei Jin, Linda Hlophe, Charlotte Elster, Andreas Nogga, Filomena M. Nunes The $(d,p)$ transfer reaction constitutes an important tool for extracting nuclear structure information such as spectroscopic factors and asymptotic normalization coefficients. In order to treat the dynamics in all reaction channels on the same footing, it is advantageous to view the $(d,p)$ reaction as a three-body problem ($n+p+A$) within a Faddeev framework. Coulomb poses severe difficulties when studying these reactions on heavy nuclei with momentum space Faddeev equations. One way to address the challenges is to formulate the problem without screening and using separable interactions. An important first step in testing this formulation is to consider the ground state of $^6$Li, since this system has been studied in detail before within a three-body $n+p+\alpha$ ansatz. For the $np$ interaction, we employ e.g. the CD-Bonn potential, and for $n+\alpha$ and $p+\alpha$ interactions Wood-Saxon type potentials. We introduce a projection method for the Pauli forbidden state which acts only in the relevant subsystem and thus leaves the structure of the Faddeev equations unaltered. Results for the energy and structure of the $^6$Li ground state will be presented for both the separable and non-separable approaches. Our results demonstrate the accuracy of the separable approach. [Preview Abstract] |
Saturday, October 28, 2017 8:42AM - 8:54AM |
NB.00002: T=3/2 Isobaric Analog States in $^9$Be populated via $^8$Li+p resonance scattering Curtis Hunt, G.V. Rogachev, S Almaraz-Calderon, A. Aprahamian, B. Bucher, W. Tan, E.D. Johnson, J. P. Mitchell, M. Avila, A. Kuchera, L. T. Baby Proton resonance scattering with rare isotope beams, studied using the Thick Target and Inverse Kinematics (TTIK) approach, has been a very productive tool to study the structure of exotic, mostly proton rich nuclei and has key advantages ex. high efficiency and excellent energy resolution. Direct implementation of TTIK for the neutron rich case would require neutron resonance scattering with a radioactive beam which is not possible at present. It has been suggested by V. Goldberg 20 years ago to study neutron rich nuclei using TTIK through corresponding isobaric analog states populated in proton resonance scattering, which has been done for a few cases. The main goal of this experiment is to benchmark the application of the TTIK technique for studies of neutron rich nuclei. The A=9 T=3/2 isobaric multiplet provides an ideal opportunity. Experimental data on proton resonances in $^9$C and on the structure of low lying states in $^9$Li are available. We have populated T=3/2 states in $^{9}$Be using $^8$Li+p resonance scattering, performed modified R-matrix analysis and compared the results to the available data for $^9$C and $^9$Li. Applicability and challenges of TTIK for neutron rich nuclei studies will be discussed. [Preview Abstract] |
Saturday, October 28, 2017 8:54AM - 9:06AM |
NB.00003: $^{6}$Li and $d+\alpha$ scattering in a three-body momentum space Faddeev model (II) Linda Hlophe, L Jin, Ch. Elster, A Nogga, F Nunes The $(d,p)$ transfer reaction constitutes an important tool for extracting nuclear structure information. In order to treat the dynamics in all reaction channels on the same footing, it is advantageous to view the $(d,p)$ reaction as a three-body problem ($n+p+A$) within a Faddeev framework. Coulomb poses severe difficulties when studying these reactions on heavy nuclei with momentum space Faddeev equations. One way to address the challenges is to formulate the problem without screening and using separable interactions. An essential ingredient of this work involved the development of the separable interactions for the NA system. Those separable representations are obtained through the EST formulation; they are multi-rank representations of realistic interactions, namely CD-Bonn for $np$ and of Woods-Saxon form for the $n(p)-\alpha$ potentials. Based on the results presented in (I), we discuss the extension of our implementation into the scattering regime. Preliminary results for angular distributions and cross sections for $d+\alpha$ scattering omitting the Coulomb interaction will be presented. Future prospects will be discussed. [Preview Abstract] |
Saturday, October 28, 2017 9:06AM - 9:18AM |
NB.00004: Pionic Fusion of $^{\mathrm{4}}$He $+ \quad^{\mathrm{12}}$C Andrew Zarrella, Sherry Yennello Pionic fusion is the process by which two nuclei fuse and then deexcite by the exclusive emission of a pion. These reactions represent the most extreme examples of deep subthreshold pion production and provide evidence for an unknown, collective mechanism for pion production. An experiment was performed at the Texas A{\&}M University Cyclotron Institute to measure the cross section of the $^{\mathrm{4}}$He $+ \quad^{\mathrm{12}}$C $\to $ $^{\mathrm{16}}$N $+ \quad \pi^{\mathrm{+}}$ reaction. The Momentum Achromat Recoil Spectrometer (MARS) was used to separate and identify the $^{\mathrm{16}}$N fusion residues and the newly constructed Partial Truncated Icosahedron (ParTI) phoswich array was used to identify charged pions. The detector responses for each phoswich unit were recorded using fast-sampling ADCs which allow all light charged particles in the ParTI phoswiches to be identified using ``fast vs. slow'' pulse shape discrimination. By writing the waveform responses, pions can also be identified by the presence of a characteristic muon decay pulse. The combination of the residue-pion coincidence and the two independent pion identification techniques represent a highly sensitive experimental design for studying pionic fusion reactions. [Preview Abstract] |
Saturday, October 28, 2017 9:18AM - 9:30AM |
NB.00005: Investigation of excited 0$^+$ states in $^{160}\text{Er}$ populated via the $(p,t)$ two-neutron transfer reaction C. Burbadge The interpretation of low-lying 0$^+$ states in rare-earth nuclei remains a highly-debated topic in nuclear structure. Resolving the nature of these states is particularly difficult due to the presence of shape coexistence which can increase the number of low-lying states, as well as the paucity of data for excited 0$^+$ states. Two-neutron transfer reactions are ideal tools for probing 0$^+ \rightarrow$ 0$^+$ transitions in deformed nuclei. In the present work, excited 0$^+$ states are studied via a series of $(p,t)$ reactions on $^{162,164,166,168}$Er targets at the Maier-Leibnitz Laboratory in Garching, Germany. Reaction products were momentum-analyzed with a Q3D magnetic spectrograph. The results confirm strong population of the 0$^{+}_{2}$ state of 18\% of the ground state strength in $^{160}$Er consistent with the strength observed in other $N=92$ isotones, suggesting a special character for this state which is inconsistent with a $\beta$-vibration interpretation. Preliminary results of the $0^{+}$ strength in the aforementioned $(p,t)$ experiments will be presented and placed into context with similar experiments in the $N = 90$ region, underlining the potential role of the $\sfrac{11}{2}^{-}[505] \nu $ orbital in the observed $0^{+}_2$ state strength. [Preview Abstract] |
Saturday, October 28, 2017 9:30AM - 9:42AM |
NB.00006: Nonlocality in inclusive A(d,p)X transfer reactions Weichuan Li, Gregory Potel, Filomena Nunes A theory for computing cross sections for inclusive A(d,p)X processes has been previously developed [1]. This includes direct neutron transfer to bound states, transfer to the continuum, as well as inelastic processes. Therein, local optical potentials are used to describe the nucleon-target interaction. We extend this framework to investigate the effects of nonlocality in the optical potentials for A(d,p)B reactions populating neutron bound and unbound states. We also consider the A(d,p)X inclusive transfer cross sections. We obtained neutron wave functions for nonlocal interactions of the Perey-Buck type within the R-matrix method [2]. We have studied A(d,p)X processes on $^{16}$O, $^{40}$Ca, $^{48}$Ca, $^{126}$Sn, $^{132}$Sn, and $^{208}$Pb at 20 and 50 MeV. We compare the results obtained with local and nonlocal optical potentials and also connect our results with those of [3]. Preliminary results will be presented. \newline\newline[1] G. Potel, F. M. Nunes, and I. J. Thompson. Establishing a theory for deuteron-induced surrogate reactions. PRC, 2015. [2] P Descouvemont and D Baye. The r-matrix theory. Reports on Progress in Physics, 2010. [3] L. J. Titus, F. M. Nunes, and G. Potel. Explicit inclusion of nonlocality in (d, p) transfer reactions. PRC, 2016. [Preview Abstract] |
Saturday, October 28, 2017 9:42AM - 9:54AM |
NB.00007: Theoretical study of intermediate mass fragments in proton-induced reactions Mohammad S Sabra Cross-section calculations, including energy spectra, angular distribution, mass and charge distributions, of secondary fragments produced by proton-induced reactions are crucial for validation of physics models used in space development. Within the framework of SAPTON model, which allows the emission of nucleons, light clusters, and intermediate mass fragments (IMFs), we have analyzed energy spectra, angular distributions, and production cross-sections for H, He, Li, Be, and B isotopes produced in collisions of 1.2, 1.9, and 2.5 GeV protons with Al target. The results are compared with the available experimental data. SAPTON reproduces the data well, suggesting that nucleons are mainly created in the intra-nuclear stage, while light clusters and IMFs are created in the surface coalescence stage, as well as in the pre-equilibrium/evaporation stages of the reaction process. [Preview Abstract] |
Saturday, October 28, 2017 9:54AM - 10:06AM |
NB.00008: Neutron cross section measurements for $^{12}$C between 0.5 and 8 MeV A.P.D. Ramirez, M.T. McEllistrem, S. Mukhopadhyay, E.E. Peters, S.W. Yates, S.F. Hicks, E.C. Derdeyn, E.M. Lyons, T.J. Morin, J.R. Vanhoy Elastic and inelastic neutron scattering experiments on $^{12}$C between 0.5 and 8 MeV are in progress at the University of Kentucky Accelerator Laboratory. Both (n,n$^{\prime}$) angular distributions and (n,n$^{\prime}\gamma$) excitation functions are measured. Neutron elastic scattering cross sections on $^{12}$C are rather well known over a wide energy range but there is great interest in reducing uncertainties even further. Angular distributions provide additional information which guides refinements of resonance parameters. Preliminary measurements suggested that at a few incident energies, the forward-angle elastic differential cross sections may be larger than indicated in the analysis of 1970s data - the multiple scattering (MS) effect is much larger and the MS yield may not have been distinguishable from background in time-of-flight spectra from that era. Few measurements of inelastic scattering exist and reported values from 4.8 to 6.4 MeV can be significantly different from each other and from the data evaluations. A status report on $^{12}$C measurements will be given, highlighting the (n,n) measurements. [Preview Abstract] |
Saturday, October 28, 2017 10:06AM - 10:18AM |
NB.00009: Archival and Dissemination of the U.S. and Canadian Experimental Nuclear Reaction Data (EXFOR Project) Boris Pritychenko, Stanislav Hlavac, Otto Schwerer, Viktor Zerkin The Exchange Format (EXFOR) or experimental nuclear reaction database and the associated Web interface provide access to the wealth of low- and intermediate-energy nuclear reaction physics data. This resource includes numerical data sets and bibliographical information for more than 22,000 experiments since the beginning of nuclear science. Analysis of the experimental data sets, recovery and archiving will be discussed. Examples of the recent developments of the data renormalization, uploads and inverse reaction calculations for nuclear science and technology applications will be presented. The EXFOR database, updated monthly, provides an essential support for nuclear data evaluation, application development and research activities. It is publicly available at the National Nuclear Data Center website http://www.nndc.bnl.gov/exfor and the International Atomic Energy Agency mirror site http://www-nds.iaea.org/exfor. [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700