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Title: Implications of PREX-2 on the electric dipole polarizability of neutron-rich nuclei

Abstract

Background: The recent announcement by the PREX collaboration of an unanticipated thick neutron skin in 208Pb ($$R^{208}_{skin}$$) has challenged the understanding of neutron-rich matter in the vicinity of nuclear saturation density. Whereas earlier constraints indicate that the symmetry energy is relatively soft, the PREX-2 result seems to suggest the opposite. Purpose: To confront constraints on the symmetry energy obtained from measurements of the electric dipole polarizability against those informed by the PREX-2 measurement of $$R^{208}_{skin}$$ and by the correlations that it entails. Methods: Here, covariant energy density functionals informed by the properties of finite nuclei are used to compute the electric dipole response of 48Ca, 68Ni, 132Sn, and 208Pb. The set of functionals used in this work are consistent with experimental data, yet are flexible enough in that they span a wide range of values of $$R^{208}_{skin}$$ Results: It is found that theoretical predictions of the electric dipole polarizability that are consistent with the PREX-2 measurement systematically overestimate the corresponding values extracted from the direct measurements of the distribution of electric dipole strength. Conclusions: The neutron skin thickness of 208Pb extracted from parity violating electron scattering and the electric dipole polarizability measured in photoabsorption experiments are two of the cleanestmore » experimental tools used to constrain the symmetry energy around nuclear saturation density. However, the recent value of $$R^{208}_{skin}$$ that suggests a fairly stiff symmetry energy stands in stark contrast to the conclusions derived from the electric dipole polarizability. At present, I offer no solution to this dilemma.« less

Authors:
ORCiD logo [1]
  1. Florida State Univ., Tallahassee, FL (United States)
Publication Date:
Research Org.:
Florida State Univ., Tallahassee, FL (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Nuclear Physics (NP)
OSTI Identifier:
1815016
Grant/Contract Number:  
FG02-92ER40750
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Physical Review C
Additional Journal Information:
Journal Volume: 104
Publisher:
American Physical Society (APS)
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS

Citation Formats

Piekarewicz, Jorge. Implications of PREX-2 on the electric dipole polarizability of neutron-rich nuclei. United States: N. p., 2021. Web. doi:10.1103/PhysRevC.104.024329.
Piekarewicz, Jorge. Implications of PREX-2 on the electric dipole polarizability of neutron-rich nuclei. United States. https://doi.org/10.1103/PhysRevC.104.024329
Piekarewicz, Jorge. 2021. "Implications of PREX-2 on the electric dipole polarizability of neutron-rich nuclei". United States. https://doi.org/10.1103/PhysRevC.104.024329.
@article{osti_1815016,
title = {Implications of PREX-2 on the electric dipole polarizability of neutron-rich nuclei},
author = {Piekarewicz, Jorge},
abstractNote = {Background: The recent announcement by the PREX collaboration of an unanticipated thick neutron skin in 208Pb ($R^{208}_{skin}$) has challenged the understanding of neutron-rich matter in the vicinity of nuclear saturation density. Whereas earlier constraints indicate that the symmetry energy is relatively soft, the PREX-2 result seems to suggest the opposite. Purpose: To confront constraints on the symmetry energy obtained from measurements of the electric dipole polarizability against those informed by the PREX-2 measurement of $R^{208}_{skin}$ and by the correlations that it entails. Methods: Here, covariant energy density functionals informed by the properties of finite nuclei are used to compute the electric dipole response of 48Ca, 68Ni, 132Sn, and 208Pb. The set of functionals used in this work are consistent with experimental data, yet are flexible enough in that they span a wide range of values of $R^{208}_{skin}$ Results: It is found that theoretical predictions of the electric dipole polarizability that are consistent with the PREX-2 measurement systematically overestimate the corresponding values extracted from the direct measurements of the distribution of electric dipole strength. Conclusions: The neutron skin thickness of 208Pb extracted from parity violating electron scattering and the electric dipole polarizability measured in photoabsorption experiments are two of the cleanest experimental tools used to constrain the symmetry energy around nuclear saturation density. However, the recent value of $R^{208}_{skin}$ that suggests a fairly stiff symmetry energy stands in stark contrast to the conclusions derived from the electric dipole polarizability. At present, I offer no solution to this dilemma.},
doi = {10.1103/PhysRevC.104.024329},
url = {https://www.osti.gov/biblio/1815016}, journal = {Physical Review C},
number = ,
volume = 104,
place = {United States},
year = {2021},
month = {8}
}

Journal Article:
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