Implications of the $^{36}\mathrm{Ca}\ensuremath{-}^{36}\mathrm{S}$ and $^{38}\mathrm{Ca}\ensuremath{-}^{38}\mathrm{Ar}$ difference in mirror charge radii on the neutron matter equation of state

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Implications of the ${}^{36}{Ca -} {}^{36}S$ and ${}^{38}{Ca -} {}^{38}{Ar}$ difference in mirror charge radii on the neutron matter equation of state

B. A. Brown, K. Minamisono, J. Piekarewicz, H. Hergert, D. Garand, A. Klose, K. König, J. D. Lantis, Y. Liu, B. Maaß, A. J. Miller, W. Nörtershäuser, S. V. Pineda, R. C. Powel, D. M. Rossi, F. Sommer, C. Sumithrarachchi, A. Teigelhöfer, J. Watkins, and R. Wirth

Phys. Rev. Research 2, 022035(R) – Published 11 May 2020

Abstract

Charge radii of the unstable ${}^{36}{Ca}$ and ${}^{38}{Ca}$ nuclei were recently determined and used to compute differences in charge radii between mirror nuclei $Δ R_{ch}$ for the ${}^{36}{Ca} - {}^{36}S$ and ${}^{38}{Ca} - {}^{38}{Ar}$ mirror pairs. Given the correlation between $Δ R_{ch}$ and the slope of the symmetry energy $L$ at the nuclear saturation density, we deduce $L = 5 - 70$ MeV, which rules out a large fraction of models that predict a “stiff” equation of state. This is the most precise determination of $L$ in this model based on electromagnetic probes of nuclear ground states. The determined range is consistent with earlier analyses from both laboratory experiments and astrophysical observations, including the recent detection of gravitational waves from the merger of two neutron stars.

Received 28 February 2020
Accepted 21 April 2020

DOI:https://doi.org/10.1103/PhysRevResearch.2.022035

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

Published by the American Physical Society

Physics Subject Headings (PhySH)

Nuclear charge distribution Nuclear matter

Nuclear Physics

Authors & Affiliations

B. A. Brown^1,2, K. Minamisono ^1,2, J. Piekarewicz ³, H. Hergert^1,2, D. Garand¹, A. Klose⁴, K. König¹, J. D. Lantis^1,5, Y. Liu ⁶, B. Maaß⁷, A. J. Miller^1,2, W. Nörtershäuser ⁷, S. V. Pineda^1,5, R. C. Powel^1,2, D. M. Rossi ⁷, F. Sommer⁷, C. Sumithrarachchi¹, A. Teigelhöfer⁸, J. Watkins ^1,2, and R. Wirth ¹

¹National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
²Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
³Department of Physics, Florida State University, Tallahassee, Florida 32306, USA
⁴Department of Chemistry, Augustana University, Sioux Falls, South Dakota 57197, USA
⁵Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA
⁶Facility for Rare Isotope Beams, Michigan State University, East Lansing, Michigan 48824, USA
⁷Institut für Kernphysik, Technische Universität Darmstadt, 64289 Darmstadt, Germany
⁸TRIUMF, Vancouver, BC V6T 2A3, Canada