• Rapid Communication

Experimental constraint on stellar electron-capture rates from the Sr88(t,He3+γ)Rb88 reaction at 115 MeV/u

J. C. Zamora, R. G. T. Zegers, Sam M. Austin, D. Bazin, B. A. Brown, P. C. Bender, H. L. Crawford, J. Engel, A. Falduto, A. Gade, P. Gastis, B. Gao, T. Ginter, C. J. Guess, S. Lipschutz, B. Longfellow, A. O. Macchiavelli, K. Miki, E. Ney, S. Noji, J. Pereira, J. Schmitt, C. Sullivan, R. Titus, and D. Weisshaar
Phys. Rev. C 100, 032801(R) – Published 23 September 2019

Abstract

The Gamow-Teller strength distribution from Sr88 was extracted from a (t,He3+γ) experiment at 115MeV/u to constrain estimates for the electron-capture rates on nuclei around N=50, between and including Ni78 and Sr88, which are important for the late evolution of core-collapse supernovae. The observed Gamow-Teller strength below an excitation energy of 8 MeV was consistent with zero and below 10 MeV amounted to 0.1±0.05. Except for a very-weak transition that could come from the 2.231-MeV 1+ state, no γ lines that could be associated with the decay of known 1+ states were identified. The derived electron-capture rate from the measured strength distribution is more than an order of magnitude smaller than rates based on the single-state approximation presently used in astrophysical simulations for most nuclei near N=50. Rates based on shell-model and quasiparticle random-phase approximation calculations that account for Pauli-blocking and core-polarization effects provide better estimates than the single-state approximation, although a relatively strong transition to the first 1+ state in Rb88 is not observed in the data. Pauli-unblocking effects due to high stellar temperatures could partially counter the low electron-capture rates. The new data serve as a zero-temperature benchmark for constraining models used to estimate such effects.

    • Received 1 February 2019
    • Revised 1 April 2019

    DOI:https://doi.org/10.1103/PhysRevC.100.032801

    ©2019 American Physical Society

    Physics Subject Headings (PhySH)

    Nuclear Physics

    Authors & Affiliations

    J. C. Zamora1,2, R. G. T. Zegers1,2,3, Sam M. Austin1,2, D. Bazin1, B. A. Brown1,2,3, P. C. Bender1, H. L. Crawford4, J. Engel5, A. Falduto6,2, A. Gade1,2,3, P. Gastis6,2, B. Gao1,2, T. Ginter1, C. J. Guess7, S. Lipschutz1,2,3, B. Longfellow1,3, A. O. Macchiavelli4, K. Miki8, E. Ney5, S. Noji1,2, J. Pereira1,2, J. Schmitt1,2,3, C. Sullivan1,2,3, R. Titus1,2,3, and D. Weisshaar1

    • 1National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
    • 2Joint Institute for Nuclear Astrophysics: CEE, Michigan State University, East Lansing, Michigan 48824, USA
    • 3Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
    • 4Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
    • 5Department of Physics and Astronomy, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
    • 6Department of Physics, Central Michigan University, Mt. Pleasant, Michigan 48859, USA
    • 7Department of Physics and Astronomy, Swarthmore College, Swarthmore, Pennsylvania 19081, USA
    • 8Department of Physics, Tohoku University, Sendai, Miyagi 980-8578, Japan

    Article Text (Subscription Required)

    Click to Expand

    References (Subscription Required)

    Click to Expand
    Issue

    Vol. 100, Iss. 3 — September 2019

    Reuse & Permissions
    Access Options
    CHORUS

    Article Available via CHORUS

    Download Accepted Manuscript

    Authorization Required


    ×
    ×

    Images

    ×

    Sign up to receive regular email alerts from Physical Review C

    Log In

    Cancel
    ×

    Search


    Article Lookup

    Paste a citation or DOI

    Enter a citation
    ×