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Bednarek I, Olchawa W, Sładkowski J, Syska J. A Statistical Approach to Neutron Stars' Crust-Core Transition Density and Pressure. ENTROPY (BASEL, SWITZERLAND) 2023; 25:1652. [PMID: 38136532 PMCID: PMC10743226 DOI: 10.3390/e25121652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2023] [Revised: 12/06/2023] [Accepted: 12/11/2023] [Indexed: 12/24/2023]
Abstract
In this paper, a regression model between neutron star crust-core pressure and the symmetry energy characteristics was estimated using the Akaike information criterion and the adjusted coefficient of determination Radj2. The most probable value of the transition density, which should characterize the crust-core environment of the sought physical neutron star model, was determined based on the obtained regression function. An anti-correlation was found between this transition density and the main characteristic of the symmetry energy, i.e., its slope L.
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Affiliation(s)
- Ilona Bednarek
- Institute of Physics, University of Silesia, 75 Pułku Piechoty 1, 41-500 Chorzów, Poland; (I.B.); (J.S.)
| | - Wiesław Olchawa
- Institute of Physics, University of Opole, Oleska 48, 45-052 Opole, Poland;
| | - Jan Sładkowski
- Institute of Physics, University of Silesia, 75 Pułku Piechoty 1, 41-500 Chorzów, Poland; (I.B.); (J.S.)
| | - Jacek Syska
- Institute of Physics, University of Silesia, 75 Pułku Piechoty 1, 41-500 Chorzów, Poland; (I.B.); (J.S.)
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2
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Neill D, Preston R, Newton WG, Tsang D. Constraining the Nuclear Symmetry Energy with Multimessenger Resonant Shattering Flares. PHYSICAL REVIEW LETTERS 2023; 130:112701. [PMID: 37001080 DOI: 10.1103/physrevlett.130.112701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 10/03/2022] [Accepted: 01/27/2023] [Indexed: 06/19/2023]
Abstract
Much effort is devoted to measuring the nuclear symmetry energy through neutron star (NS) and nuclear observables. Since matter in the NS core may be nonhadronic, observables like radii and tidal deformability may not provide reliable constraints on properties of nucleonic matter. By performing the first consistent inference using ensembles of core and crust equations of state from astrophysical and nuclear data, we demonstrate that coincident timing of a resonant shattering flare (RSF) and gravitational wave signal during binary NS inspiral probes the crust-core transition region and provides constraints on the symmetry energy comparable to terrestrial nuclear experiments. We show that nuclear masses, RSFs, and measurements of NS radii and tidal deformabilities constrain different density ranges of the equation of state, providing complementary probes.
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Affiliation(s)
- Duncan Neill
- Department of Physics, University of Bath, Claverton Down, Bath, United Kingdom
| | - Rebecca Preston
- Department of Physics and Astronomy, Texas A&M University-Commerce, Commerce, Texas, USA
| | - William G Newton
- Department of Physics and Astronomy, Texas A&M University-Commerce, Commerce, Texas, USA
| | - David Tsang
- Department of Physics, University of Bath, Claverton Down, Bath, United Kingdom
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3
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The Symmetry Energy: Current Status of Ab Initio Predictions vs. Empirical Constraints. Symmetry (Basel) 2023. [DOI: 10.3390/sym15020450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023] Open
Abstract
Infinite nuclear matter is a suitable laboratory to learn about nuclear forces in many-body systems. In particular, modern theoretical predictions of neutron-rich matter are timely because of recent and planned experiments aimed at constraining the equation of state of isospin-asymmetric matter. For these reasons, we have taken a broad look at the equation of state of neutron-rich matter and the closely related symmetry energy, which is the focal point of this article. Its density dependence is of paramount importance for a number of nuclear and astrophysical systems, ranging from neutron skins to the structure of neutron stars. We review and discuss ab initio predictions in relation to recent empirical constraints. We emphasize and demonstrate that free-space nucleon–nucleon data pose stringent constraints on the density dependence of the neutron matter equation of state, which essentially determines the slope of the symmetry energy at saturation.
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4
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Huth S, Pang PTH, Tews I, Dietrich T, Le Fèvre A, Schwenk A, Trautmann W, Agarwal K, Bulla M, Coughlin MW, Van Den Broeck C. Constraining neutron-star matter with microscopic and macroscopic collisions. Nature 2022; 606:276-280. [PMID: 35676430 PMCID: PMC9177417 DOI: 10.1038/s41586-022-04750-w] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Accepted: 04/11/2022] [Indexed: 11/16/2022]
Abstract
Interpreting high-energy, astrophysical phenomena, such as supernova explosions or neutron-star collisions, requires a robust understanding of matter at supranuclear densities. However, our knowledge about dense matter explored in the cores of neutron stars remains limited. Fortunately, dense matter is not probed only in astrophysical observations, but also in terrestrial heavy-ion collision experiments. Here we use Bayesian inference to combine data from astrophysical multi-messenger observations of neutron stars1-9 and from heavy-ion collisions of gold nuclei at relativistic energies10,11 with microscopic nuclear theory calculations12-17 to improve our understanding of dense matter. We find that the inclusion of heavy-ion collision data indicates an increase in the pressure in dense matter relative to previous analyses, shifting neutron-star radii towards larger values, consistent with recent observations by the Neutron Star Interior Composition Explorer mission5-8,18. Our findings show that constraints from heavy-ion collision experiments show a remarkable consistency with multi-messenger observations and provide complementary information on nuclear matter at intermediate densities. This work combines nuclear theory, nuclear experiment and astrophysical observations, and shows how joint analyses can shed light on the properties of neutron-rich supranuclear matter over the density range probed in neutron stars.
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Affiliation(s)
- Sabrina Huth
- Department of Physics, Technische Universität Darmstadt, Darmstadt, Germany.
- ExtreMe Matter Institute EMMI, GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany.
| | - Peter T H Pang
- Nikhef, Amsterdam, The Netherlands.
- Institute for Gravitational and Subatomic Physics (GRASP), Utrecht University, Utrecht, The Netherlands.
| | - Ingo Tews
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Tim Dietrich
- Institut für Physik und Astronomie, Universität Potsdam, Potsdam, Germany
- Max Planck Institute for Gravitational Physics (Albert Einstein Institute), Potsdam, Germany
| | - Arnaud Le Fèvre
- GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany
| | - Achim Schwenk
- Department of Physics, Technische Universität Darmstadt, Darmstadt, Germany
- ExtreMe Matter Institute EMMI, GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany
- Max-Planck-Institut für Kernphysik, Heidelberg, Germany
| | | | - Kshitij Agarwal
- Physikalisches Institut, Eberhard Karls Universität Tübingen, Tübingen, Germany
| | - Mattia Bulla
- The Oskar Klein Centre, Department of Astronomy, Stockholm University, AlbaNova, Stockholm, Sweden
| | - Michael W Coughlin
- School of Physics and Astronomy, University of Minnesota, Minneapolis, MN, USA
| | - Chris Van Den Broeck
- Nikhef, Amsterdam, The Netherlands
- Institute for Gravitational and Subatomic Physics (GRASP), Utrecht University, Utrecht, The Netherlands
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5
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Pacilio C, Maselli A, Fasano M, Pani P. Ranking Love Numbers for the Neutron Star Equation of State: The Need for Third-Generation Detectors. PHYSICAL REVIEW LETTERS 2022; 128:101101. [PMID: 35333071 DOI: 10.1103/physrevlett.128.101101] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 01/22/2022] [Accepted: 02/10/2022] [Indexed: 06/14/2023]
Abstract
Gravitational-wave measurements of the tidal deformability in neutron-star binary coalescences can be used to infer the still unknown equation of state (EOS) of dense matter above the nuclear saturation density. By employing a Bayesian-ranking test, we quantify the ability of current and future gravitational-wave observations to discriminate among families of nuclear-physics based EOS which differ in particle content and ab initio microscopic calculations. While the constraining power of GW170817 is limited, we show that even twenty coalescences detected by LIGO-Virgo at design sensitivity are not enough to discriminate between EOS with similar softness but distinct microphysics. However, just a single detection with a third-generation detector such as the Einstein Telescope or Cosmic Explorer will rule out several families of EOS with very strong statistical significance and can discriminate among models which feature similar softness, hence, constraining the properties of nuclear matter to unprecedented levels.
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Affiliation(s)
- Costantino Pacilio
- Dipartimento di Fisica, "Sapienza" Università di Roma, Piazzale Aldo Moro 5, 00185 Roma, Italy
- INFN, Sezione di Roma, Piazzale Aldo Moro 2, 00185 Roma, Italy
| | - Andrea Maselli
- Gran Sasso Science Institute (GSSI), I-67100 L'Aquila, Italy
- INFN, Laboratori Nazionali del Gran Sasso, I-67100 Assergi, Italy
| | - Margherita Fasano
- Dipartimento di Fisica, "Sapienza" Università di Roma, Piazzale Aldo Moro 5, 00185 Roma, Italy
| | - Paolo Pani
- Dipartimento di Fisica, "Sapienza" Università di Roma, Piazzale Aldo Moro 5, 00185 Roma, Italy
- INFN, Sezione di Roma, Piazzale Aldo Moro 2, 00185 Roma, Italy
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6
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Quantifying the Effect of Initial Fluctuations on Isospin-Sensitive Observables from Heavy-Ion Collisions at Intermediate Energies. Symmetry (Basel) 2021. [DOI: 10.3390/sym13112172] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Initial fluctuation is one of the ingredients that washes fingerprints of the nuclear symmetry energy on observables in heavy-ion collisions. By artificially using the same initial nuclei in all collision events, the effect of the initial fluctuation on isospin-sensitive observables, e.g., the yield ratio of free neutrons with respect to protons Nn/Np, 3H/3He yield ratio, the yield ratio between charged pions π−/π+, and the elliptic flow ratio or difference between free neutrons and protons v2n/v2p (v2n-v2p), are studied within the ultrarelativistic quantum molecular dynamics (UrQMD) model. In practice, Au + Au collisions with impact parameter b = 5 fm and beam energy Elab = 400 MeV/nucleon are calculated. It is found that the effect of the initialization on the yields of free protons and neutrons is small, while for the yield of pions, the directed and elliptic flows are found to be apparently influenced by the choice of initialization because of the strong memory effects. Regarding the isospin-sensitive observables, the effect of the initialization on Nn/Np and 3H/3He is negligible, while π−/π+ and v2n/v2p (v2n-v2p) display a distinct difference among different initializations. The fingerprints of symmetry energy on π−/π+ and v2n/v2p can be either enhanced or reduced when different initializations are utilized.
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7
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Symmetry Energy and the Pauli Exclusion Principle. Symmetry (Basel) 2021. [DOI: 10.3390/sym13112116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
In this article we present a classical potential that respects the Pauli exclusion principle and can be used to describe nucleon-nucleon interactions at intermediate energies. The potential depends on the relative momentum of the colliding nucleons and reduces interactions at low momentum transfer mimicking the Pauli exclusion principle. We use the potential with Metropolis Monte Carlo methods and study the formation of finite nuclei and infinite systems. We find good agreement in terms of the binding energies, radii, and internal nucleon distribution of finite nuclei, and the binding energy in nuclear matter and neutron star matter, as well as the formation of nuclear pastas, and the symmetry energy of neutron star matter.
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8
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Abstract
The effective Gogny interactions of the D1 family were established by D. Gogny more than forty years ago with the aim to describe simultaneously the mean field and the pairing field corresponding to the nuclear interaction. The most popular Gogny parametrizations, namely D1S, D1N and D1M, describe accurately the ground-state properties of spherical and deformed finite nuclei all across the mass table obtained with Hartree–Fock–Bogoliubov (HFB) calculations. However, these forces produce a rather soft equation of state (EoS) in neutron matter, which leads to predict maximum masses of neutron stars well below the observed value of two solar masses. To remove this limitation, we built new Gogny parametrizations by modifying the density dependence of the symmetry energy predicted by the force in such a way that they can be applied to the neutron star domain and can also reproduce the properties of finite nuclei as good as their predecessors. These new parametrizations allow us to obtain stiffer EoS’s based on the Gogny interactions, which predict maximum masses of neutron stars around two solar masses. Moreover, other global properties of the star, such as the moment of inertia and the tidal deformability, are in harmony with those obtained with other well tested EoSs based on the SLy4 Skyrme force or the Barcelona–Catania–Paris–Madrid (BCPM) energy density functional. Properties of the core-crust transition predicted by these Gogny EoSs are also analyzed. Using these new Gogny forces, the EoS in the inner crust is obtained with the Wigner–Seitz approximation in the Variational Wigner–Kirkwood approach along with the Strutinsky integral method, which allows one to estimate in a perturbative way the proton shell and pairing corrections. For the outer crust, the EoS is determined basically by the nuclear masses, which are taken from the experiments, wherever they are available, or by HFB calculations performed with these new forces if the experimental masses are not known.
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9
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Abstract
Background: We analyze several constraints on the nuclear equation of state (EOS) currently available from neutron star (NS) observations and laboratory experiments and study the existence of possible correlations among properties of nuclear matter at saturation density with NS observables. Methods: We use a set of different models that include several phenomenological EOSs based on Skyrme and relativistic mean field models as well as microscopic calculations based on different many-body approaches, i.e., the (Dirac–)Brueckner–Hartree–Fock theories, Quantum Monte Carlo techniques, and the variational method. Results: We find that almost all the models considered are compatible with the laboratory constraints of the nuclear matter properties as well as with the largest NS mass observed up to now, 2.14−0.09+0.10M⊙ for the object PSR J0740+6620, and with the upper limit of the maximum mass of about 2.3–2.5M⊙ deduced from the analysis of the GW170817 NS merger event. Conclusion: Our study shows that whereas no correlation exists between the tidal deformability and the value of the nuclear symmetry energy at saturation for any value of the NS mass, very weak correlations seem to exist with the derivative of the nuclear symmetry energy and with the nuclear incompressibility.
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10
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Li H, Xu HJ, Zhou Y, Wang X, Zhao J, Chen LW, Wang F. Probing the Neutron Skin with Ultrarelativistic Isobaric Collisions. PHYSICAL REVIEW LETTERS 2020; 125:222301. [PMID: 33315427 DOI: 10.1103/physrevlett.125.222301] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 10/15/2020] [Indexed: 06/12/2023]
Abstract
Particle production in ultrarelativistic heavy ion collisions depends on the details of the nucleon density distributions in the colliding nuclei. We demonstrate that the charged hadron multiplicity distributions in isobaric collisions at ultrarelativistic energies provide a novel approach to determine the poorly known neutron density distributions and thus the neutron skin thickness in finite nuclei, which can in turn put stringent constraints on the nuclear symmetry energy.
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Affiliation(s)
- Hanlin Li
- College of Science, Wuhan University of Science and Technology, Wuhan, Hubei 430065, China
| | - Hao-Jie Xu
- School of Science, Huzhou University, Huzhou, Zhejiang 313000, China
| | - Ying Zhou
- School of Physics and Astronomy and Shanghai Key Laboratory for Particle Physics and Cosmology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Xiaobao Wang
- School of Science, Huzhou University, Huzhou, Zhejiang 313000, China
| | - Jie Zhao
- Department of Physics and Astronomy, Purdue University, West Lafayette, Indiana 47907, USA
| | - Lie-Wen Chen
- School of Physics and Astronomy and Shanghai Key Laboratory for Particle Physics and Cosmology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Fuqiang Wang
- School of Science, Huzhou University, Huzhou, Zhejiang 313000, China
- Department of Physics and Astronomy, Purdue University, West Lafayette, Indiana 47907, USA
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11
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Drischler C, Furnstahl RJ, Melendez JA, Phillips DR. How Well Do We Know the Neutron-Matter Equation of State at the Densities Inside Neutron Stars? A Bayesian Approach with Correlated Uncertainties. PHYSICAL REVIEW LETTERS 2020; 125:202702. [PMID: 33258658 DOI: 10.1103/physrevlett.125.202702] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Revised: 07/28/2020] [Accepted: 09/25/2020] [Indexed: 06/12/2023]
Abstract
We introduce a new framework for quantifying correlated uncertainties of the infinite-matter equation of state derived from chiral effective field theory (χEFT). Bayesian machine learning via Gaussian processes with physics-based hyperparameters allows us to efficiently quantify and propagate theoretical uncertainties of the equation of state, such as χEFT truncation errors, to derived quantities. We apply this framework to state-of-the-art many-body perturbation theory calculations with nucleon-nucleon and three-nucleon interactions up to fourth order in the χEFT expansion. This produces the first statistically robust uncertainty estimates for key quantities of neutron stars. We give results up to twice nuclear saturation density for the energy per particle, pressure, and speed of sound of neutron matter, as well as for the nuclear symmetry energy and its derivative. At nuclear saturation density, the predicted symmetry energy and its slope are consistent with experimental constraints.
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Affiliation(s)
- C Drischler
- Department of Physics, University of California, Berkeley, California 94720, USA
- Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - R J Furnstahl
- Department of Physics, The Ohio State University, Columbus, Ohio 43210, USA
| | - J A Melendez
- Department of Physics, The Ohio State University, Columbus, Ohio 43210, USA
| | - D R Phillips
- Department of Physics and Astronomy and Institute of Nuclear and Particle Physics, Ohio University, Athens, Ohio 45701, USA
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12
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13
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Fasano M, Abdelsalhin T, Maselli A, Ferrari V. Constraining the Neutron Star Equation of State Using Multiband Independent Measurements of Radii and Tidal Deformabilities. PHYSICAL REVIEW LETTERS 2019; 123:141101. [PMID: 31702173 DOI: 10.1103/physrevlett.123.141101] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 07/24/2019] [Indexed: 06/10/2023]
Abstract
Using a Bayesian approach, we combine measurements of neutron star macroscopic observables obtained by astrophysical and gravitational observations to derive joint constraints on the equation of state (EOS) of matter at supranuclear density. In our analysis, we use two sets of data: (i) the masses and tidal deformabilities measured in the binary neutron star event GW170817, detected by LIGO and Virgo, and (ii) the masses and stellar radii measured from observations of nuclear bursts in accreting low-mass x-ray binaries. Using a phenomenological parametrization of the equation of state, we compute the posterior probability distributions of the EOS parameters, using which we infer the posterior distribution for the radius and the mass of the two neutron stars of GW170817. The constraints we set on the radii are tighter than previous bounds.
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Affiliation(s)
- Margherita Fasano
- Dipartimento di Fisica, Sapienza Università di Roma & Sezione INFN Roma1, P.A. Moro 5, 00185, Roma, Italy
| | - Tiziano Abdelsalhin
- Dipartimento di Fisica, Sapienza Università di Roma & Sezione INFN Roma1, P.A. Moro 5, 00185, Roma, Italy
| | - Andrea Maselli
- Dipartimento di Fisica, Sapienza Università di Roma & Sezione INFN Roma1, P.A. Moro 5, 00185, Roma, Italy
| | - Valeria Ferrari
- Dipartimento di Fisica, Sapienza Università di Roma & Sezione INFN Roma1, P.A. Moro 5, 00185, Roma, Italy
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14
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Nuclear Equation of State for Compact Stars and Supernovae. THE PHYSICS AND ASTROPHYSICS OF NEUTRON STARS 2018. [DOI: 10.1007/978-3-319-97616-7_6] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
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15
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Novel halos in light kaonic nuclei as an indicator of nuclear equation of state at supra-normal densities. Sci Rep 2017; 7:16695. [PMID: 29196755 PMCID: PMC5711962 DOI: 10.1038/s41598-017-16877-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 11/17/2017] [Indexed: 11/08/2022] Open
Abstract
The sensitive correlations between the low-density halo structure and the high-density properties of the nuclear equation of state (EOS) are constructed in light kaonic nuclei with the relativistic mean-field theory. More specifically, the 1p 1/2 halo spreads out linearly with increasing the pressure and sound velocity square at supra-normal densities and decreasing the incompressibility at saturation density. These results suggest that the novel halo in light kaonic nuclei can serve as a sensitive indicator of the nuclear EOS of symmetric matter at supra-normal densities. The experimental production and detection of the light kaonic nuclei, yet to be available, is discussed in some details at last.
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16
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Zhang Y, Tsang M, Li Z, Liu H. Influence of Skyrme-type interaction on HICs observables. EPJ WEB OF CONFERENCES 2016. [DOI: 10.1051/epjconf/201611707025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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17
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Ou L, Xiao Z, Yi H, Wang N, Liu M, Tian J. Dynamic Isovector Reorientation of Deuteron as a Probe to Nuclear Symmetry Energy. PHYSICAL REVIEW LETTERS 2015; 115:212501. [PMID: 26636849 DOI: 10.1103/physrevlett.115.212501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Indexed: 06/05/2023]
Abstract
We present the calculations on a novel reorientation effect of deuteron attributed to isovector interaction in the nuclear field of heavy target nuclei. The correlation angle determined by the relative momentum vector of the proton and the neutron originating from the breakup deuteron, which is experimentally detectable, exhibits significant dependence on the isovector nuclear potential but is robust against the variation of the isoscaler sector. In terms of sensitivity and cleanness, the breakup reactions induced by the polarized deuteron beam at about 100 MeV/u provide a more stringent constraint to the symmetry energy at subsaturation densities.
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Affiliation(s)
- Li Ou
- College of Physics and Technology, Guangxi Normal University, Guilin 541004, China
- State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Zhigang Xiao
- Department of Physics, Tsinghua University, Beijing 100084, China
- Collaborative Innovation Center of Quantum Matter, Beijing 100084, China
| | - Han Yi
- Department of Physics, Tsinghua University, Beijing 100084, China
| | - Ning Wang
- College of Physics and Technology, Guangxi Normal University, Guilin 541004, China
- State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Min Liu
- College of Physics and Technology, Guangxi Normal University, Guilin 541004, China
| | - Junlong Tian
- School of Physics and Electrical Engineering, Anyang Normal University, Anyang 455000, China
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18
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19
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De Filippo E. Probing the nuclear symmetry energy with heavy-ion collisions. EPJ WEB OF CONFERENCES 2015. [DOI: 10.1051/epjconf/20158800020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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20
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Zana L. Neutron skins from Coherent Pion Photoproduction. EPJ WEB OF CONFERENCES 2015. [DOI: 10.1051/epjconf/20159601036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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21
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Stone JR. High-density matter: current status and future challenges. EPJ WEB OF CONFERENCES 2015. [DOI: 10.1051/epjconf/20159502006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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22
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Colonna M, Baran V, Rizzo C. Isospin effects in heavy-ion reactions: Results from transport theories. EPJ WEB OF CONFERENCES 2015. [DOI: 10.1051/epjconf/20158800027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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23
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Tarbert CM, Watts DP, Glazier DI, Aguar P, Ahrens J, Annand JRM, Arends HJ, Beck R, Bekrenev V, Boillat B, Braghieri A, Branford D, Briscoe WJ, Brudvik J, Cherepnya S, Codling R, Downie EJ, Foehl K, Grabmayr P, Gregor R, Heid E, Hornidge D, Jahn O, Kashevarov VL, Knezevic A, Kondratiev R, Korolija M, Kotulla M, Krambrich D, Krusche B, Lang M, Lisin V, Livingston K, Lugert S, MacGregor IJD, Manley DM, Martinez M, McGeorge JC, Mekterovic D, Metag V, Nefkens BMK, Nikolaev A, Novotny R, Owens RO, Pedroni P, Polonski A, Prakhov SN, Price JW, Rosner G, Rost M, Rostomyan T, Schadmand S, Schumann S, Sober D, Starostin A, Supek I, Thomas A, Unverzagt M, Walcher T, Zana L, Zehr F. Neutron skin of (208)pb from coherent pion photoproduction. PHYSICAL REVIEW LETTERS 2014; 112:242502. [PMID: 24996085 DOI: 10.1103/physrevlett.112.242502] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2014] [Indexed: 06/03/2023]
Abstract
Information on the size and shape of the neutron skin on (208)Pb is extracted from coherent pion photoproduction cross sections measured using the Crystal Ball detector together with the Glasgow tagger at the MAMI electron beam facility. On exploitation of an interpolated fit of a theoretical model to the measured cross sections, the half-height radius and diffuseness of the neutron distribution are found to be c(n)=6.70±0.03(stat.) fm and a(n)=0.55±0.01(stat.)(-0.03)(+0.02)(sys.) fm, respectively, corresponding to a neutron skin thickness Δr(np)=0.15±0.03(stat.)(-0.03)(+0.01)(sys.) fm. The results give the first successful extraction of a neutron skin thickness with an electromagnetic probe and indicate that the skin of (208)Pb has a halo character. The measurement provides valuable new constraints on both the structure of nuclei and the equation of state for neutron-rich matter.
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Affiliation(s)
- C M Tarbert
- SUPA, School of Physics, University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom
| | - D P Watts
- SUPA, School of Physics, University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom
| | - D I Glazier
- SUPA, School of Physics, University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom
| | - P Aguar
- Institut für Kernphysik, University of Mainz, Germany
| | - J Ahrens
- Institut für Kernphysik, University of Mainz, Germany
| | - J R M Annand
- SUPA, Department of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - H J Arends
- Institut für Kernphysik, University of Mainz, Germany
| | - R Beck
- Institut für Kernphysik, University of Mainz, Germany and Helmholtz-Institut für Strahlen- und Kernphysik, University Bonn, Germany
| | - V Bekrenev
- Petersburg Nuclear Physics Institute, Gatchina, Russia
| | - B Boillat
- Institut für Physik, University of Basel, Basel, Switzerland
| | | | - D Branford
- SUPA, School of Physics, University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom
| | - W J Briscoe
- Center for Nuclear Studies, The George Washington University, Washington, D.C. 20052, USA
| | - J Brudvik
- University of California at Los Angeles, Los Angeles, California 90095, USA
| | | | - R Codling
- SUPA, Department of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - E J Downie
- SUPA, Department of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - K Foehl
- SUPA, School of Physics, University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom
| | - P Grabmayr
- Physikalisches Institut Universität Tübingen, Tübingen, Germany
| | - R Gregor
- II. Physikalisches Institut, University of Giessen, Germany
| | - E Heid
- Institut für Kernphysik, University of Mainz, Germany
| | - D Hornidge
- Mount Allison University, Sackville, New Brunswick E4L 1E6, Canada
| | - O Jahn
- Institut für Kernphysik, University of Mainz, Germany
| | | | - A Knezevic
- Rudjer Boskovic Institute, Zagreb, Croatia
| | | | - M Korolija
- Rudjer Boskovic Institute, Zagreb, Croatia
| | - M Kotulla
- Institut für Physik, University of Basel, Basel, Switzerland
| | - D Krambrich
- Institut für Kernphysik, University of Mainz, Germany and Helmholtz-Institut für Strahlen- und Kernphysik, University Bonn, Germany
| | - B Krusche
- Institut für Physik, University of Basel, Basel, Switzerland
| | - M Lang
- Institut für Kernphysik, University of Mainz, Germany and Helmholtz-Institut für Strahlen- und Kernphysik, University Bonn, Germany
| | - V Lisin
- Institute for Nuclear Research, Moscow, Russia
| | - K Livingston
- SUPA, Department of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - S Lugert
- II. Physikalisches Institut, University of Giessen, Germany
| | - I J D MacGregor
- SUPA, Department of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - D M Manley
- Kent State University, Kent, Ohio 44240, USA
| | - M Martinez
- Institut für Kernphysik, University of Mainz, Germany
| | - J C McGeorge
- SUPA, Department of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | | | - V Metag
- II. Physikalisches Institut, University of Giessen, Germany
| | - B M K Nefkens
- University of California at Los Angeles, Los Angeles, California 90095, USA
| | - A Nikolaev
- Institut für Kernphysik, University of Mainz, Germany and Helmholtz-Institut für Strahlen- und Kernphysik, University Bonn, Germany
| | - R Novotny
- II. Physikalisches Institut, University of Giessen, Germany
| | - R O Owens
- SUPA, Department of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | | | - A Polonski
- Institute for Nuclear Research, Moscow, Russia
| | - S N Prakhov
- University of California at Los Angeles, Los Angeles, California 90095, USA
| | - J W Price
- University of California at Los Angeles, Los Angeles, California 90095, USA
| | - G Rosner
- SUPA, Department of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - M Rost
- Institut für Kernphysik, University of Mainz, Germany
| | | | - S Schadmand
- II. Physikalisches Institut, University of Giessen, Germany
| | - S Schumann
- Institut für Kernphysik, University of Mainz, Germany and Helmholtz-Institut für Strahlen- und Kernphysik, University Bonn, Germany
| | - D Sober
- The Catholic University of America, Washington, D.C. 20064, USA
| | - A Starostin
- University of California at Los Angeles, Los Angeles, California 90095, USA
| | - I Supek
- Rudjer Boskovic Institute, Zagreb, Croatia
| | - A Thomas
- Institut für Kernphysik, University of Mainz, Germany
| | - M Unverzagt
- Institut für Kernphysik, University of Mainz, Germany and Helmholtz-Institut für Strahlen- und Kernphysik, University Bonn, Germany
| | - Th Walcher
- Institut für Kernphysik, University of Mainz, Germany
| | - L Zana
- SUPA, School of Physics, University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom
| | - F Zehr
- Institut für Physik, University of Basel, Basel, Switzerland
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24
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Verde G. Probing the nuclear equation-of-state and the symmetry energy with heavy-ion collisions. EPJ WEB OF CONFERENCES 2014. [DOI: 10.1051/epjconf/20146601018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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25
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Gandolfi S, Steiner AW. From nuclear structure to neutron stars. EPJ WEB OF CONFERENCES 2014. [DOI: 10.1051/epjconf/20146601017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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26
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Pagano E, Verde G, Minniti T, Danielewicz P, Barker B. Proton-proton femtoscopy and access to dynamical sources at intermediate energies. EPJ WEB OF CONFERENCES 2014. [DOI: 10.1051/epjconf/20146603068] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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27
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28
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Brown BA. Constraints on the Skyrme equations of state from properties of doubly magic nuclei. PHYSICAL REVIEW LETTERS 2013; 111:232502. [PMID: 24476262 DOI: 10.1103/physrevlett.111.232502] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Indexed: 06/03/2023]
Abstract
I use properties of doubly magic nuclei to constrain symmetric nuclear matter and neutron matter equations of state. I conclude that these data determine the value of the neutron equation of state at a density of ρ(on)=0.10 nucleons/fm3 to be 11.4(10) MeV. The slope at that point is constrained by the value of the neutron skin. Analytical equations are given that show the dependence of the Skyrme equations of state on the neutron skin.
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Affiliation(s)
- B Alex Brown
- Department of Physics and Astronomy and National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824-1321, USA
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29
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Fattoyev FJ, Piekarewicz J. Has a thick neutron skin in 208Pb been ruled out? PHYSICAL REVIEW LETTERS 2013; 111:162501. [PMID: 24182259 DOI: 10.1103/physrevlett.111.162501] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Indexed: 06/02/2023]
Abstract
The Lead Radius Experiment has provided the first model-independent evidence in favor of a neutron-rich skin in 208Pb. Although the error bars are large, the reported large central value of 0.33 fm is particularly intriguing. To test whether such a thick neutron skin in 208Pb is already incompatible with laboratory experiments or astrophysical observations, we employ relativistic models with neutron-skin thickness in 208Pb ranging from 0.16 to 0.33 fm to compute ground-state properties of finite nuclei, their collective monopole and dipole response, and mass-versus-radius relations for neutron stars. No compelling reason was found to rule out models with large neutron skins in 208Pb from the set of observables considered in this Letter.
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Affiliation(s)
- F J Fattoyev
- Department of Physics and Astronomy, Texas A&M University-Commerce, Commerce, Texas 75429, USA
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30
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Kabtoul M, Bougault R, Colonna M, Galichet E. Chemistry of nuclear particle production in 32 A MeV136,124Xe+124,112Sn reactions and nuclear symmetry energy. EPJ WEB OF CONFERENCES 2012. [DOI: 10.1051/epjconf/20123100010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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31
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Sotani H, Nakazato K, Iida K, Oyamatsu K. Probing the equation of state of nuclear matter via neutron star asteroseismology. PHYSICAL REVIEW LETTERS 2012; 108:201101. [PMID: 23003135 DOI: 10.1103/physrevlett.108.201101] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2011] [Indexed: 06/01/2023]
Abstract
We general-relativistically calculate the frequency of fundamental torsional oscillations of neutron star crusts, where we focus on the crystalline properties obtained from macroscopic nuclear models in a way that is dependent on the equation of state of nuclear matter. We find that the calculated frequency is sensitive to the density dependence of the symmetry energy, but almost independent of the incompressibility of symmetric nuclear matter. By identifying the lowest-frequency quasiperiodic oscillation in giant flares observed from soft gamma-ray repeaters as the fundamental torsional mode and allowing for the dependence of the calculated frequency on stellar models, we provide a lower limit of the density derivative of the symmetry energy as L≃50 MeV.
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Affiliation(s)
- Hajime Sotani
- National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan
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32
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Abrahamyan S, Ahmed Z, Albataineh H, Aniol K, Armstrong DS, Armstrong W, Averett T, Babineau B, Barbieri A, Bellini V, Beminiwattha R, Benesch J, Benmokhtar F, Bielarski T, Boeglin W, Camsonne A, Canan M, Carter P, Cates GD, Chen C, Chen JP, Hen O, Cusanno F, Dalton MM, De Leo R, de Jager K, Deconinck W, Decowski P, Deng X, Deur A, Dutta D, Etile A, Flay D, Franklin GB, Friend M, Frullani S, Fuchey E, Garibaldi F, Gasser E, Gilman R, Giusa A, Glamazdin A, Gomez J, Grames J, Gu C, Hansen O, Hansknecht J, Higinbotham DW, Holmes RS, Holmstrom T, Horowitz CJ, Hoskins J, Huang J, Hyde CE, Itard F, Jen CM, Jensen E, Jin G, Johnston S, Kelleher A, Kliakhandler K, King PM, Kowalski S, Kumar KS, Leacock J, Leckey J, Lee JH, LeRose JJ, Lindgren R, Liyanage N, Lubinsky N, Mammei J, Mammoliti F, Margaziotis DJ, Markowitz P, McCreary A, McNulty D, Mercado L, Meziani ZE, Michaels RW, Mihovilovic M, Muangma N, Muñoz-Camacho C, Nanda S, Nelyubin V, Nuruzzaman N, Oh Y, Palmer A, Parno D, Paschke KD, Phillips SK, Poelker B, Pomatsalyuk R, Posik M, Puckett AJR, Quinn B, Rakhman A, Reimer PE, Riordan S, Rogan P, Ron G, Russo G, Saenboonruang K, Saha A, Sawatzky B, Shahinyan A, Silwal R, Sirca S, Slifer K, Solvignon P, Souder PA, Sperduto ML, Subedi R, Suleiman R, Sulkosky V, Sutera CM, Tobias WA, Troth W, Urciuoli GM, Waidyawansa B, Wang D, Wexler J, Wilson R, Wojtsekhowski B, Yan X, Yao H, Ye Y, Ye Z, Yim V, Zana L, Zhan X, Zhang J, Zhang Y, Zheng X, Zhu P. Measurement of the neutron radius of 208Pb through parity violation in electron scattering. PHYSICAL REVIEW LETTERS 2012; 108:112502. [PMID: 22540469 DOI: 10.1103/physrevlett.108.112502] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2012] [Indexed: 05/31/2023]
Abstract
We report the first measurement of the parity-violating asymmetry A(PV) in the elastic scattering of polarized electrons from 208Pb. A(PV) is sensitive to the radius of the neutron distribution (R(n)). The result A(PV)=0.656±0.060(stat)±0.014(syst) ppm corresponds to a difference between the radii of the neutron and proton distributions R(n)-R(p)=0.33(-0.18)(+0.16) fm and provides the first electroweak observation of the neutron skin which is expected in a heavy, neutron-rich nucleus.
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33
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Steiner AW, Gandolfi S. Connecting neutron star observations to three-body forces in neutron matter and to the nuclear symmetry energy. PHYSICAL REVIEW LETTERS 2012; 108:081102. [PMID: 22463511 DOI: 10.1103/physrevlett.108.081102] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2011] [Indexed: 05/31/2023]
Abstract
Using a phenomenological form of the equation of state of neutron matter near the saturation density which has been previously demonstrated to be a good characterization of quantum Monte Carlo simulations, we show that currently available neutron star mass and radius measurements provide a significant constraint on the equation of state of neutron matter. At higher densities we model the equation of state by using polytropes and a quark matter model. We show that observations offer an important constraint on the strength of the three-body force in neutron matter, and thus some theoretical models of the three-body force may be ruled out by currently available astrophysical data. In addition, we obtain an estimate of the symmetry energy of nuclear matter and its slope that can be directly compared to the experiment and other theoretical calculations.
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Affiliation(s)
- A W Steiner
- Joint Institute for Nuclear Astrophysics, National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
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34
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Baldo M, Burgio GF. Properties of the nuclear medium. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2012; 75:026301. [PMID: 22790345 DOI: 10.1088/0034-4885/75/2/026301] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We review our knowledge on the properties of the nuclear medium that have been studied, over many years, on the basis of many-body theory, laboratory experiments and astrophysical observations. Throughout the presentation particular emphasis is placed on the possible relationship and links between the nuclear medium and the structure of nuclei, including the limitations of such an approach. First we consider the realm of phenomenological laboratory data and astrophysical observations and the hints they can give on the characteristics that the nuclear medium should possess. The analysis is based on phenomenological models, that however have a strong basis on physical intuition and an impressive success. More microscopic models are also considered, and it is shown that they are able to give invaluable information on the nuclear medium, in particular on its equation of state. The interplay between laboratory experiments and astrophysical observations is particularly stressed, and it is shown how their complementarity enormously enriches our insights into the structure of the nuclear medium. We then introduce the nucleon-nucleon interaction and the microscopic many-body theory of nuclear matter, with a critical discussion about the different approaches and their results. The Landau-Fermi liquid theory is introduced and briefly discussed, and it is shown how fruitful it can be in discussing the macroscopic and low-energy properties of the nuclear medium. As an illustrative example, we discuss neutron matter at very low density, and it is shown how it can be treated within the many-body theory. The general bulk properties of the nuclear medium are reviewed to indicate at which stage of our knowledge we stand, taking into account the most recent developments both in theory and experiments. A section is dedicated to the pairing problem. The connection with nuclear structure is then discussed, on the basis of the energy density functional method. The possibility of linking the physics of exotic nuclei and the astrophysics of neutron stars is particularly stressed. Finally, we discuss the thermal properties of the nuclear medium, in particular the liquid-gas phase transition and its connection with the phenomenology on heavy ion reactions and the cooling evolution of neutron stars. The presentation has been taken for non-specialists and possibly for non-nuclear physicists.
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Affiliation(s)
- M Baldo
- Instituto Nazionale di Fisica Nucleare, Sez. di Catania, Via S Sofia 64 95123 Catania, Italy.
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35
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Roca-Maza X, Centelles M, Viñas X, Warda M. Neutron skin of (208)Pb, nuclear symmetry energy, and the parity radius experiment. PHYSICAL REVIEW LETTERS 2011; 106:252501. [PMID: 21770635 DOI: 10.1103/physrevlett.106.252501] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2011] [Indexed: 05/31/2023]
Abstract
A precise determination of the neutron skin Δr(np) of a heavy nucleus sets a basic constraint on the nuclear symmetry energy (Δr(np) is the difference of the neutron and proton rms radii of the nucleus). The parity radius experiment (PREX) may achieve it by electroweak parity-violating electron scattering (PVES) on (208)Pb. We investigate PVES in nuclear mean field approach to allow the accurate extraction of Δr(np) of (208)Pb from the parity-violating asymmetry A(PV) probed in the experiment. We demonstrate a high linear correlation between A(PV) and Δr(np) in successful mean field forces as the best means to constrain the neutron skin of (208)Pb from PREX, without assumptions on the neutron density shape. Continuation of the experiment with higher precision in A(PV) is motivated since the present method can support it to constrain the density slope of the nuclear symmetry energy to new accuracy.
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Affiliation(s)
- X Roca-Maza
- Departament d'Estructura i Constituents de la Matèria and Institut de Ciències del Cosmos, Facultat de Física, Universitat de Barcelona, Diagonal 647, 08028 Barcelona, Spain
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36
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Iwata Y, Otsuka T, Maruhn JA, Itagaki N. Suppression of charge equilibration leading to the synthesis of exotic nuclei. PHYSICAL REVIEW LETTERS 2010; 104:252501. [PMID: 20867368 DOI: 10.1103/physrevlett.104.252501] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2010] [Indexed: 05/29/2023]
Abstract
Charge equilibration between two colliding nuclei can take place in the early stage of heavy-ion collisions. A basic mechanism of charge equilibration is presented in terms of the extension of single-particle motion from one nucleus to the other, from which the upper energy limit of the bombarding energy is introduced for significant charge equilibration. The formula for this limit is presented, and is compared to various experimental data. It is examined also by comparison to three-dimensional time-dependent density functional calculations. The suppression of charge equilibration, which appears in collisions at the energies beyond the upper energy limit, gives rise to remarkable effects on the synthesis of exotic nuclei with extreme proton-neutron asymmetry.
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Affiliation(s)
- Yoritaka Iwata
- GSI Helmholtzzentrum für Schwerionenforschung, D-64291 Darmstadt, Germany
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37
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Natowitz JB, Röpke G, Typel S, Blaschke D, Bonasera A, Hagel K, Klähn T, Kowalski S, Qin L, Shlomo S, Wada R, Wolter HH. Symmetry energy of dilute warm nuclear matter. PHYSICAL REVIEW LETTERS 2010; 104:202501. [PMID: 20867023 DOI: 10.1103/physrevlett.104.202501] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2010] [Indexed: 05/29/2023]
Abstract
The symmetry energy of nuclear matter is a fundamental ingredient in the investigation of exotic nuclei, heavy-ion collisions, and astrophysical phenomena. New data from heavy-ion collisions can be used to extract the free symmetry energy and the internal symmetry energy at subsaturation densities and temperatures below 10 MeV. Conventional theoretical calculations of the symmetry energy based on mean-field approaches fail to give the correct low-temperature, low-density limit that is governed by correlations, in particular, by the appearance of bound states. A recently developed quantum-statistical approach that takes the formation of clusters into account predicts symmetry energies that are in very good agreement with the experimental data. A consistent description of the symmetry energy is given that joins the correct low-density limit with quasiparticle approaches valid near the saturation density.
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Affiliation(s)
- J B Natowitz
- Cyclotron Institute, Texas A&M University, College Station, Texas 77843-3366, USA
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38
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Difficulties in probing density dependent symmetry potential with the HBT interferometry. ACTA ACUST UNITED AC 2009. [DOI: 10.1007/s11433-009-0210-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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