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Level lifetimes determined with the DSAM after fast neutron scattering and relevance to neutrinoless double-beta decay

ORAL

Abstract

Neutrinoless double-$\beta$ decay (0$\nu\beta\beta$) has not been observed but is being sought in several large-scale experiments. The nuclear matrix elements for 0$\nu\beta\beta$ cannot be determined experimentally and must be calculated from nuclear structure models. Our recent measurements have focused on providing detailed nuclear structure data to guide these model calculations. At the University of Kentucky Accelerator Laboratory (UKAL), we have performed spectroscopic studies with the (n,n$^\prime\gamma$) reaction on $^{76}$Ge, which is widely regarded as one of the best candidates for the observation of 0$\nu\beta\beta$, and $^{76}$Se, its double-$\beta$ decay daughter. While $^{76}$Ge can be well understood from shell model calculations,$^{76}$Se cannot. To better characterize this transitional region of triaxiality, studies of the lighter stable Ge nuclei, such as $^{74}$Ge, have been initiated. From these measurements, new excited states were identified, level lifetimes were measured with the Doppler-shift attenuation method, multipole mixing ratios were established, and transition probabilities were determined. In the case of $^{74}$Ge, a great deal of information is now available, and shell model calculations explain the low-lying, low-spin structure very well.

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Authors

  • S.W. Yates

    University of Kentucky Depts. of Chemistry and Physics \& Astronomy

  • S. Mukhopadhyay

    Univ. of Oslo, TU Dresden, J Hopkins Univ. Applied Physics Lab, NSCL, Ohio University, Univ. of Frankfurt, Hope College, LANL, Mississippi State Univ., Univ. of Delhi, Univ. of Notre Dame, TAMU, LLNL, Instituto de Fisica Corpuscular, Mississippi State University, University of Victoria, University of Notre Dame, Michigan State University, ELI-NP, MIT, James Madison University, Washington University, St. Louis, UNC - Chapel Hill and TUNL, Duke University and TUNL, Lawrence Livermore National Laboratory, Department of Physics, North Carolina State University, Center for Theoretical As- trophysics, Los Alamos National Laboratory, Department of Physics, North Carolina State University,, Department of Physics and Columbia Astrophysics Laboratory, Columbia University, Los Alamos National Laboratory, North Carolina State University, Columbia University, Northwestern Univ, Soreq NRC, Lawrence Livermore Natl Lab, The Racah Institute of Physics, The Hebrew University of Jerusalem, University of Tennessee, Knoxville, National Institute of Standards and Technology, Texas A&M University, Agile Technologies, Inc., University of Kentucky, Tennessee Technological University, University of Tennessee, Louisiana State University / Argonne National Laboratory, Argonne National Laboratory, Florida State University, National Superconducting Cyclotron Laboratory, Oak Ridge National Laboratory, Institut fur Theoretische Physik II, Univ. Erlangen-Nurnberg, Erlangen, Germany, TRIUMF, Vancouver, BC, Canada, Physics Division, Oak Ridge National Lab., Oak Ridge, TN 37831, USA, Technische Univ. Darmstadt, 64289 Darmstadt, Germany, National Superconducting Cyclotron Lab., MSU, East Lansing, MI 48824, Dept. of Chemistry, Augustana Univ., Sioux Falls, SD 57197, USA, University of Maryland, Baltimore County, California State University, Northridge, Bethel University, University of Minnesota Duluth, Vassar College, University of Wisconsin-Madison, Wittenberg University, Duke University, Tsinghua University, Joint Institute for Nuclear Research, Lawrence Berkeley National Lab, Vanderbilt University, University of Alabama, None, University of Michigan, Rutgers University, GANIL, Indiana University Bloomington, Duke University/Triangle Universities Nuclear Laboratory, MSU, NSCL, Rutgers Univ., ORNL, Univ. of Tennessee Knoxville, Institut d'Astronomie et d'Astrophysique, ULB, 1050 Brussels, Belgium, TUNL, Durham, NC 27708, USA \& University of North Carolina at Chapel Hill, Chapel Hill, NC 27516, USA, Department of Physics and Astronomy, James Madison University, Harrisonburg, VA 22807, USA, University of California Berkeley, Central Michigan University, University of Oslo, Utah State University, Institute of Theoretical Physics and Astronomy, Vilnius University, Forschungszentrum Julich, Bonn University, Jefferson Lab, Temple University, ANU, TRIUMF, UML, BNL, Institut fur Kernphysik der Universitat zu Koln, Ruder Boskovic Institute, University of York, Michigan State University/NSCL, University of Surrey, National Superconducting Cyclotron Laboratory, MSU, Lawrence Berkeley National Laboratory, Research Center for Nuclear Astrophysics, Universität zu Köln, University of Massachusetts, Lowell, Simon Fraser University, Albion College, Massachusetts Institute of Technology, Old Dominion University, IPN-Orsay, The Catholic University of America, OU, MPIK, WMU, CMU, UCB, MSU, Notre Dame, UOslo, MissSU, NSCL / MSU, Rutgers, George Washington University, William and Mary, Thomas Jefferson National Accelerator Facility, CERN, Old Dominion University & Jefferson Lab, University of Maryland, College Park, Cyclotron Institute, Texas A&M University, TX, 77840, Department of Chemistry, Washington University, St. Louis, Missouri, IRFU, CEA, Saclay, Gif-Sur-Ivette, France, LSU, CSM, Tenn. Tech., Tennessee, Notre Dame University, Texas A\&M University, Lawerence Livermore National Laboratory, University of Tennessee Knoxville/Oak Ridge National Laboratory, FSU, U. Surrey, CSNSM-Orsay, JYFL-Jyvaskyla, ANL, VECC-Kolkata, U. Manchester, UMass Lowell, Louisiana State University, Daresbury Laboratory, University of Liverpool, University of North Carolina/TUNL, United States Naval Academy, Jefferson Lab/Old Dominion University, Penn State Berks/Jefferson Lab, Lebanon Valley College, UCLA, Penn State Berks, Lebanon Valley College/College of William and Mary, San Diego State University, Los Alamos National Lab, University of Illinois at Urbana-Champaign, Pennsylvania State University, Tel Aviv University, Stony Brook University, Brookhaven National Laboratory, Technical University of Munich, Germany, Mississippi State University, USA, UC Berkeley, UC Irvine, UNC/TUNL, Colorado School of Mines, Tennessee Technical University, Australian Natl Univ, iThemba LABS, iThemba LABS, and University of Stellenbosch, iThemba LABS, and University of Witwatersrand, RCNP, University of Osaka, Department of Physics, Florida State University, Tallahassee, Fl 32306, USA, IRFU, CEA, Université Paris-Saclay, Michigan State University and University of Tennessee, University of Indiana, University of Tennessee at Knoxville, Tennessee Tech University, Seattle University, Davidson College, National Superconducting Cyclotron Laboratory (NSCL), Jefferson Labs, Central Piedmont Community College, Jeffersion Lab, Drake University, University College Cork, University of Wisconsin - La Crosse, University of Tokyo, Tohoku University, University of Groningen, Osaka University, Kyoto University, Saint Mary's College, Konan University, The Institut de Physique Nucleaire Orsay, Texas A&M University Cyclotron Institute, Shaanxi Normal University, Houghton College, Bundesamt für Strahlenshutz (Germany), Ohio Wesleyan University, Bundesamt f\"{u}r Strahlenshutz, Goethe University Frankfurt, Ursinus, UW, Davidson, Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA, Fudan University, Oakridge National Laboratory, University of Massachusetts Lowell, NSCL, Michigan State Univ, Advanced Science Research Center, Japan Atomic Energy Agency, NSCL, Michigan State University, Ursinus College, Universidade de S\~{a}o Paulo, NSCL/MSU, Institute of Modern Physics, Swarthmore College, Institut f$\ddot{\rm u}$r Kernphysik, Technische Universit$\ddot{\rm a}$t Darmstadt/GSI/ Max-Plank-Institute f$\ddot{\rm u}$r Kernphysik, Institut f$\ddot{\rm u}$r Kernphysik, Technische Universit$\ddot{\rm a}$t Darmstadt, Physics Division, ORNL, NSCL/Department of Chemistry, MSU, NSCL, MSU, Department of Chemistry, Augustana University, NSCL/Department of Physics and Astronomy, MSU, UTK, Saint Mary’s University, Faculty of Chemistry, Adam Mickiewicz University, Faculty of Physics, University of Warsaw, GSI, Darmstadt, IKP, TU Darmstadt, Physics Division, Argonne National Laboratory, Ohio State University, CNRS/IP2N3 Bordeaux, France, University of Illinois at Chicago, Caltech, University of Dallas, Jefferson Laboratory, University of Florida, CEA/DAM, France, IAEA, ITA, Academy of Sciences of the Czech Republic, The Henryk Niewodniczanski Institute of Nuclear Physics (IFJ PAN), Indiana University South Bend, Cyclotron Institute / Texas A\&M University, North Carolina State University, TUNL, European X-ray Free Electron Laser GmbH, U. of Victoria, LBNL, Berkeley, CA, SLAC, Menlo Park, CA, Jefferson Lab, Newport News, VA 23606, University of Kentucky Depts. of Chemistry and Physics \& Astronomy

  • E.E. Peters

    University of Kentucky Depts. of Chemistry and Physics \& Astronomy

  • A.P.D. Ramirez

    University of Kentucky Depts. of Chemistry and Physics \& Astronomy

  • B.P. Crider

    Mississippi State University, Mississippi State Univ., Mississippi State University Dept. of Physics \& Astronomy