Bulletin of the American Physical Society
2021 Fall Meeting of the APS Division of Nuclear Physics
Volume 66, Number 8
Monday–Thursday, October 11–14, 2021; Virtual; Eastern Daylight Time
Session FF: Nuclear Structure: Light Nuclei II |
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Chair: Vandana Tripathi, FSU Room: Berkeley & Clarendon |
Tuesday, October 12, 2021 2:00PM - 2:12PM |
FF.00001: Probing Spin-Isospin Excitations in Proton-Rich Nuclei via the (p,n) Reaction Jaclyn M Schmitt, Remco G Zegers, Francesc Yasid Ayyad Limonge, Daniel Bazin, Alyssa Davis, Miles DeNudt, Bingshui Gao, Charles E Hultquist, Hironori Iwasaki, Shumpei Noji, Jorge Pereira, Andreas Stolz, Juan C Zamora Tracking the evolution of nuclear properties away from stability serves as a valuable test for nuclear models. In the present work, the (p,n) charge-exchange reaction is used to test the extraction of β- GT strengths and other nuclear structure information from proton-rich unstable isotopes. The 11C(p,n)11N reaction was measured in inverse kinematics at 100 MeV/A at the National Superconducting Cyclotron Laboratory (NSCL). The extracted B(GT) will be compared to results from mirror 11B(n,p)-type reactions and to predictions of theoretical models. Progress of the analysis for this experiment will be presented. This experiment is the first time the (p,n) probe has been used on the proton-rich side of the nuclear chart, and the feasibility of using this probe to study heavier isotopes up to the 100Sn region during the FRIB era will also be discussed. |
Tuesday, October 12, 2021 2:12PM - 2:24PM Not Participating |
FF.00002: The structure of 10Li by proton elastic scattering of T=2 isobaric analogue states in 10Be Dustin P Scriven, Grigory V Rogachev, Gregory Christian, Cody E Parker, Jack E Bishop, Evgeniy Koshchiy, Sunghoon Ahn, Eric Aboud, Michael J Roosa, Curtis Hunt, Antti Saastamoinen, Emily Harris, Alexandra Bosh The structure of the neutron unbound system 10Li is not full determined. The low-lying level structure of 10Li is important for describing the 9Li core plus neutron interaction which plays a role in other systems like the Borromean 2n-halo systems 11Li. In the ground state, the neutron is unbound by about 25 keV which has been observed as an s-wave scattering state in neutron decay experiments. The system has also been probed by 9Li(d,p) which showed no evidence of this scattering state. The 10Li system can be explored by investigating T=2 isobaric analogue states in 10Be. Here we present preliminary experimental results from an experiment with the TexAT-TPC to measure the excitation function of those T=2 states in 10Be via proton elastic scattering. |
Tuesday, October 12, 2021 2:24PM - 2:36PM |
FF.00003: Study of 11Be excited states via the 10Be(d,p) reaction in SOLARIS with the AT-TPC Daniel Bazin, Zach M Serikow, Nabin Rijal, Jie Chen, Wolfgang Mittig, Saul Beceiro-Novo, Yassid Ayyad, Clémentine Santamaria This contribution reports on the commissioning of using transfer reactions in inverse kinematics in SOLARIS with the Active Target Time Projection Chamber (AT-TPC). The goal of this experiment is to establish the possibility to perform transfer reactions at low beam intensities, typically 1-2 kHz, using the high luminosity provided by the AT-TPC. A beam of 10Be was accelerated to about 9 MeV/u in the ReA6 linac and delivered to the AT-TPC placed in a 3 Tesla magnetic field provided by the SOLARIS solenoid. The AT-TPC was filled with pure deuterium gas at atmospheric pressure. The four reaction channels 10Be(d,p), 10Be(d,d), 10Be(d,t) and 10Be(d,α) were detected simultaneously. The preliminary analysis of these reactions will be presented, with emphasis on the 10Be(d,p) channel that populates bound and unbound states in 11Be, with a particular interest towards a 3.41 MeV state for which the parity is still unknown. The 10Be(d,t) channel populates unbound states in 9Be that can decay via double α emission. The possibility to perform transfer reaction measurements at that intensity level opens many new exciting prospects with the soon-to-be-available rare isotope re-accelerated beams of FRIB. |
Tuesday, October 12, 2021 2:36PM - 2:48PM |
FF.00004: A search for novel β--delayed proton decay in 11Be at NSCL Jason Surbrook, Yassid Ayyad, Tamas A Budner, Marco Cortesi, Moshe Friedman, Cathleen E Fry, Brent E Glassman, Molly A Janasik, Aaron Kruskie, Ruchi Mahajan, Emanuel Pollacco, Michael J Roosa, Jordan Stomps, Lijie Sun, Tyler Wheeler, Christopher L Wrede In 2014, the apparent transmutation of a 11Be sample gathered at CERN-ISOLDE into 10Be was observed by applying the accelerator mass spectrometry (AMS) technique to the sample. The inferred β--delayed proton branch was nearly two orders of magnitude greater than expected; however, in 2019, a direct measurement of the 11Be(β-p) decay at TRIUMF yielded a similarly large proton branch intensity. A series of new AMS measurements from 2020 observed 10Be production rates yielding a β-p intensity upper limit that is inconsistent with both previous (AMS, direct) measurements. Contamination of the 11Be sample by molecular 10BeH in the low-energy beam is a plausible explanation for the AMS measurement inconsistencies. |
Tuesday, October 12, 2021 2:48PM - 3:00PM |
FF.00005: A Search for the 12Be Isomeric State Xinyi Wang, Paul L Gueye, Thomas Baumann, Paul A Deyoung, Nathan H Frank, Anthony N Kuchera, Belen Monteagudo, Thomas H Redpath, Georgia Votta, Henry Webb The spectroscopy of the neutron unbound 13Be is key to understanding the unexpected structural changes of neutron-rich nuclei around N=8. Invariant mass spectra from current experiments cannot determine the 1/2- p-wave location. This p-wave resonance is expected to strongly decay to a long-lived 02+ state in 12Be with a mean lifetime of 331(12) ns. Its decay scheme has a 20% branch through the 12Be(2+ ) to the ground state (2.1 MeV) and 80% for an E0 transition giving two 511 keV gamma rays from positron annihilation. |
Tuesday, October 12, 2021 3:00PM - 3:12PM |
FF.00006: Excited neutron halo of 16N via the 16Ng,m(d,3He) reaction Tsz Leung Tang, Calem R Hoffman, Benjamin P Kay, Ivan Tolstukhin, Jin Wu, Patrick Copp, Melina Avila, Daniel Santiago-Gonzalez, Heshani Jayatissa, Sana Stolze, Jeongseog Song, Gemma L Wilson, David K Sharp, Hooi Jin Ong, Sergio Almaraz-Calderon, Benjamin W Asher, Yassid Ayyad, Kyle W Brown, Daniel Bazin, Jie Chen, Matthew Hall, Kelly A Chipps We report on result from a study of the 16Ng,m(d,3He)15C reaction to explore the one neutron halo nucleus 15C. The radioactive 16N beam, with a 25% isomer component, was produced using the ATLAS RAISOR in-flight separator at ANL. The 16Ng,m(d,3He)15C proton removal reactions in inverse kinematics at 11.8 MeV/u was carried out using the HELIOS spectrometer. The simultaneous reactions provided the most direct and reliable comparison of the spectroscopic factors due to the cancellation of most of the systematic uncertainties from experiment and DWBA theory. The ratio of the spectroscopic factors between the 16Ng→15C(0.74) and 16Nm→15C(0.00) reactions was found to be 0.82±0.22. The result indicates that the s-orbital between 16Nm and 15C ground state is similar and the isomer state of 16N is an excited neutron halo state. |
Tuesday, October 12, 2021 3:12PM - 3:24PM |
FF.00007: Angular Correlation Measurements of Highly Continuum-Coupled Particle-Unbound Superradiant Nuclear States Kenneth G Hanselman, Ingo L Wiedenhoever, Lagy T Baby, Gordon W McCann, Kevin T Macon, Erin C Good, Catherine M Deibel, Balakrishnan Sudarsan, Jeffrey A Tostevin There is now a community-wide push in nuclear physics away from isotopic stability and toward the nucleon driplines and the continuum beyond. As modern accelerator facilities grant access to nuclei near the driplines, it becomes necessary to study the effect of the continuum on nuclear excitations. Recent angular correlations between decay protons from unbound 13N states and the deuteron ejectiles from the 12C(3He,d) direct proton transfer reaction which populated them have been measured using the SE-SPS (Super-Enge Split-Pole Spectrograph) at FSU, including so-called "superradiant" states strongly coupled to the continuum. These angular correlations will be presented as a powerful and insightful tool to probe complex, continuum-coupled nuclear wavefunctions as the community continues to push the limits of stability. |
Tuesday, October 12, 2021 3:24PM - 3:36PM |
FF.00008: The Nature of the 24O Core in 25F Heather L Crawford Nuclei with extreme proton-to-neutron ratios are key to testing shell-model and other theoretical approaches. One isotopic chain which has received considerable attention is the O isotopes, which are accessible for ab-initio theoretical approaches, and have proven sensitive to details of the fundamental NN and 3N interactions employed. |
Tuesday, October 12, 2021 3:36PM - 3:48PM |
FF.00009: Study of clustering in 16O by four α decay Clementine A Santamaria, Daniel Bazin, Wolfgang Mittig, Francesc Yasid Ayyad Limonge, Nabin Rijal Alpha clustering in nuclei is very important to understand better the structure of nuclei. For example, clustering in the 12C Hoyle state is responsible for enhancing the triple-α reaction in stars. Recent experiments have been capable of detecting all of the three α decays from this Hoyle state and demonstrated the sequential decay of this state. |
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