Measuring cross-sections of unbound mirror states: a systematic study of one-proton and one-neutron reactions adding on N=Z targets

ORAL

Abstract

One-neutron adding reactions are often used to infer proton-capture rates in mirror systems. While isospin is approximately symmetric, the degree to which it's still symmetric in systems with weak binding is unknown. Isobaric analog states should exhibit the same behavior, but weakly bound states experience Thomas-Erhman shifts and it is unknown how this affects the cross section. A series of experiments at Florida State University has been completed with the aim to be able to quantify asymmetries in spectroscopic factors due to weakly bound or unbound protons for calculating astrophysical reaction rates.

Targets of N=Z nuclei 24Mg and 28Si were used to populated mirror states via one-neutron and one-proton adding reactions. Beams of deuterium and 3He were impinged onto these targets, and four reactions were measured in the Super-Enge Split-Pole Spectrograph: 24Mg(d,p)25Mg, 24Mg(3He,d)25Al, 28Si(d,p)29Si and 28Si(3He,d)29P. Using the same targets, experimental setup and beam energy per nucleon, these systematic measurements populated states up to and beyond the respective neutron and proton separation energies (from 0 to at least 8 MeV in all cases), which in each mirror pair differs by ~5 MeV. Preliminary cross sections will be presented for these bound and unbound mirror states.

*Work supported by U.S. Dept of Energy via Award DE-FG02-96ER40978

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Presenters

  • Gemma L Wilson

    • Louisiana State University
    • Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803, USA

Authors

  • Gemma L Wilson

    • Louisiana State University
    • Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803, USA

  • Catherine M Deibel

    • Louisiana State University

  • Jeffery C Blackmon

    • Louisiana State University

  • Ingo L Wiedenhoever

    • Florida State University

  • Gordon W McCann

    • Florida State University

  • Lagy T Baby

    • Florida State University

  • Philip Adsley

    • Texas A&M University

  • Rajat Aggarwal

    • Florida State University
    • FSU

  • Samuel O Ajayi

    • Florida State University

  • Balakrishnan Sudarsan

    • Louisiana State University

  • Caleb B Benetti

    • Florida State University

  • Akhil Bhardwaj

    • Louisiana State University
    • LSU

  • William D Braverman

    • Louisiana State University
    • LSU

  • Keilah Davis

    • Louisiana State University

  • Peter DeRosa

    • Florida State University
    • FSU

  • Alex C Conley

    • Florida State University
    • FSU

  • Kenneth G Hanselman

    • Florida State University

  • David He

    • Louisiana State University
    • LSU

  • Brian Kelly

    • Florida State University
    • FSU

  • Eilens L Lopez Saavedra

    • Florida State University

  • Molly McLain

    • Louisiana State University
    • LSU

  • Ashton B Morelock

    • Florida State University

  • Khang H Pham

    • Louisiana State University

  • Vignesh Sitaraman

    • Florida State University

  • Samantha R Waller

    • University of North Carolina at Charlotte
    • LSU

  • Catur Wibisono

    • Florida State University