Isospin in Fragment Production

Baran, V.; Colonna, M.; Toro, M. Di; Greco, V.

doi:10.1142/9789812705143_0025

Cited by 125 publications

(250 citation statements)

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“…As it stands, the relativistic model contains 14 undetermined parameters (1 meson mass, 3 Yukawa couplings, and 10 meson self-interaction terms). Note that if one incorporates the occasionally-used scalar-isovector δ-meson [11,12], then 9 additional parameters must be included to this order (1 Yukawa coupling, and 8 meson self-interaction terms).…”

Section: A Relativistic Mean-field Modelsmentioning

confidence: 99%

Accurate calibration of relativistic mean-field models: Correlating observables and providing meaningful theoretical uncertainties

Fattoyev

Piekarewicz

2011

Phys. Rev. C

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Theoretical uncertainties in the predictions of relativistic mean-field models are estimated using a chi-square minimization procedure that is implemented by studying the small oscillations around the chi-square minimum. By diagonalizing the matrix of second derivatives, one gains access to a wealth of information-in the form of powerful correlations-that would normally remain hidden. We illustrate the power of the covariance analysis by using two relativistic mean-field models: (a) the original linear Walecka model and (b) the accurately calibrated FSUGold parametrization. In addition to providing meaningful theoretical uncertainties for both model parameters and predicted observables, the covariance analysis establishes robust correlations between physical observables. In particular, we show that whereas the correlation coefficient between the slope of the symmetry energy and the neutron-skin thickness of Lead is indeed very large, a 1% measurement of the neutron radius of Lead may only be able to constrain the slope of the symmetry energy to about 30%.

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Section: A Relativistic Mean-field Modelsmentioning

confidence: 99%

Accurate calibration of relativistic mean-field models: Correlating observables and providing meaningful theoretical uncertainties

Fattoyev

Piekarewicz

2011

Phys. Rev. C

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“…Based on the realistic nucleon-nucleon interactions, the Brueckner-Hartree-Fock (BHF) and Dirac-BruecknerHartree-Fock (DBHF) calculations predict a neutron-proton mass splitting of m * n > m * p [3,4,5]. However, the relativistic mean-field (RMF) theory gives a contrary result after the inclusion of the isovector mesons ρ and δ [6,7]. The Skyrme-Hartree-Fock (SHF) predicts both splittings of m * n > m * p and m * n < m * p exist with different Skyrme parameters [7].…”

mentioning

confidence: 99%

“…However, the relativistic mean-field (RMF) theory gives a contrary result after the inclusion of the isovector mesons ρ and δ [6,7]. The Skyrme-Hartree-Fock (SHF) predicts both splittings of m * n > m * p and m * n < m * p exist with different Skyrme parameters [7]. More realistically, the mass splitting of neutron and proton has been constrained from the energy dependence of the Lane (symmetry) potential by the nucleon-nucleus scattering experimental data, which moderately supports the mass splitting of m * n > m * p [8].…”

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confidence: 99%

Effective mass splitting of neutron and proton and isospin emission in heavy-ion collisions

Feng

2012

Nuclear Physics A

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Within the framework of an isospin and momentum dependent transport model, the emissions of isospin particles (nucleons and light clusters) squeezed out in heavy-ion collisions are investigated as probes of the poorly known symmetry energy at high baryon density. Two different mass splittings of neutrons and protons in nuclear medium as m * n > m * p and m * n < m * p are used in the model and their influence on the isospin emission in heavy-ion collisions is discussed thoroughly.The competition between the stiffness and the momentum dependence of the symmetry potential on reaction dynamics are compared and systematically analyzed. It is found that the difference of the neutron and proton directed flows and the transverse momentum distribution of the neutron/proton ratio are sensitive to the stiffness of the symmetry energy, which can not be changed with the controversial effective mass splitting. The elliptic flows of free nucleons at high transverse momentum within mid-rapidity emission are a promising observable as distinguishing the nucleon effective mass splitting.PACS : 21.65.Ef, 24.10.Lx, 25.75.-q Keywords: isospin and momentum dependent transport model; isospin particles; symmetry energy; effective mass splitting It has been well established the fact that the effective nucleon mass in nuclear matter or finite nuclei deviates from its vacuum value [1,2]. Moreover, a splitting of neutron and proton effective mass (here, the nonrelativistic mass (Landau mass) is concerned in accordance with the definition in Ref.[3]) appears in neutron-rich matter, which increases with the isospin asymmetry.

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“…For example, calculations using Landau-Fermi-liquid theory [3] and the nonrelativistic Brueckner-Hartree-Fock theory [4] present a neutron-proton mass splitting of m * n > m * p , whereas other calculations using relativistic mean-field theory and relativistic Dirac-Brueckener theory [5,6] give a contrary result. The Skyrme-Hartree-Fock approach predicts both splitting of m * n > m * p and m * n < m * p exist with different Skyrme parameters [7]. The nucleon Landau mass splitting in neutron-rich matter results from the momentum-dependence of the symmetry potential, which directly affects the isospin transport in heavy-ion collisions and consequently the extraction of the density dependence of the symmetry energy.…”

Section: Ergy; Effective Mass Splittingmentioning

confidence: 99%

“…There are a lot of works on the constraints of the density dependence of the symmetry energy from heavy-ion collisions, which has important application in nuclear physics [7,8,10,11,12] and also in astrophysics [13,14]. It is possible to use the heavy-ion reactions with neutron-rich beams to explore the density-dependent symmetry energy and the effective mass splitting of neutron and proton in the nuclear matter.…”

Section: Ergy; Effective Mass Splittingmentioning

confidence: 99%

Isospin splitting of nucleon effective mass and symmetry energy in isotopic nuclear reactions

Guo¹,

Chen²,

Niu³

et al. 2017

Chinese Phys. C

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Within an isospin and momentum dependent transport model, the dynamics of isospin particles (nucleons and light clusters) in Fermi-energy heavy-ion collisions are investigated for constraining the isospin splitting of nucleon effective mass and the symmetry energy at subsaturation densities.The mass splitting of m * n > m * p and m * n < m * p in nuclear matter and the different stiffness of symmetry energy are used in the model. The single and double neutron to proton ratios of free nucleons and light particles are thoroughly investigated in the isotopic nuclear reactions of 112 Sn+ 112 Sn and 124 Sn+ 124 Sn at the incident energies of 50 and 120 MeV/nucleon, respectively.It is found that the both effective mass splitting and symmetry energy impact the kinetic energy spectra of the single ratios, in particular at the high energy tail (larger than 20 MeV). Specific constraints are obtained from the double ratio spectra, which are evaluated from the ratios of isospin observables produced in 124 Sn+ 124 Sn over 112 Sn+ 112 Sn collisions. A mass splitting of m * n < m * p is constrained from the available data at the energy of 120 MeV/nucleon. A soft symmetry energy with the stiffness of γ s =0.5 is close to the experimental double ratio spectra at both energies.

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Isospin in Fragment Production

Cited by 125 publications

References 0 publications

Accurate calibration of relativistic mean-field models: Correlating observables and providing meaningful theoretical uncertainties

Accurate calibration of relativistic mean-field models: Correlating observables and providing meaningful theoretical uncertainties

Effective mass splitting of neutron and proton and isospin emission in heavy-ion collisions

Isospin splitting of nucleon effective mass and symmetry energy in isotopic nuclear reactions

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