Structure of $^{21}$Mg excited states studied in single neutron knockout

ORAL

Abstract

Previously, the $^{21}$Mg excited-state properties have been studied using the three-neutron transfer reaction $^{24}$Mg($^{3}$He,$^{6}$He)$^{21}$Mg directed by comparison to the $^{21}$F mirror nucleus. When comparing the experimental results to USD shell-model calculations, however, significant discrepancies are found. To resolve these discrepancies, we investigated the nucleus in a one-neutron knockout reaction $^{9}$Be($^{22}$Mg,$^{21}$Mg)X and studied the subsequent $\gamma$ decay using in-beam $\gamma$-ray spectroscopy. From the $\gamma$-decay measurement, energies of the excited states were determined. Furthermore, properties of the states were identified through the decay branching ratios to lower lying states, the spectroscopic factors for the $^{22}$Mg ground state with respect to the individual $^{21}$Mg states, and the longitudinal momentum distribution of the residual nucleus which is sensitive to the orbital angular momentum of the knocked-out neutron.

*Supported by NSF grants: PHY-0606007 and PHY-0555366.

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Authors

  • C. Aa. Diget

    • National Superconducting Cyclotron Laboratory, Michigan State University, Michigan

  • P. Adrich

    • National Superconducting Cyclotron Laboratory, Michigan State University, Michigan

  • D. Bazin

    • National Superconducting Cyclotron Laboratory, Michigan State University, Michigan

  • M.D. Bowen

    • National Superconducting Cyclotron Laboratory, Michigan State University, Michigan

  • B.A. Brown

    • National Superconducting Cyclotron Laboratory, Michigan State University, Michigan

  • C.M. Campbell

    • National Superconducting Cyclotron Laboratory, Michigan State University, Michigan

  • J.M. Cook

    • National Superconducting Cyclotron Laboratory, Michigan State University, Michigan

  • A. Gade

    • National Superconducting Cyclotron Laboratory, Michigan State University, Michigan

  • T. Glasmacher

    • National Superconducting Cyclotron Laboratory, Michigan State University, Michigan

  • S. McDaniel

    • National Superconducting Cyclotron Laboratory, Michigan State University, Michigan

  • A. Obertelli

    • National Superconducting Cyclotron Laboratory, Michigan State University, Michigan

  • K. Siwek

    • National Superconducting Cyclotron Laboratory, Michigan State University, Michigan

  • J.R. Terry

    • National Superconducting Cyclotron Laboratory, Michigan State University, Michigan

  • D. Weisshaar

    • National Superconducting Cyclotron Laboratory, Michigan State University, Michigan

  • K. Hosier

    • Department of Physics and Astronomy, Ursinus College, Pennsylvania

  • D. McGlinchery

    • Department of Physics and Astronomy, Ursinus College, Pennsylvania

  • L.A. Riley

    • Department of Physics and Astronomy, Ursinus College, Pennsylvania