Saturation of asymmetric nuclear matter
International Nuclear Information System (INIS)
We examine relations among the parameters characterizing the phenomenological equation of state (EOS) of nearly symmetric, uniform nuclear matter near the saturation density by comparing macroscopic calculations of radii and masses of stable nuclei with the experimental data. The EOS parameters of interest here are the symmetry energy S0, the density symmetry coefficient L, and the incompressibility K0 of symmetric nuclear matter at the normal nuclear density. In this study, we also examine the incompressibility of asymmetric matter, which was fixed in a certain functional form in our previous study. This parameter could be important in the description of neutron-rich nuclei and neutron-star matter. In the present study, we treat the incompressibility of the asymmetric matter as a free parameter in fitting the masses and radii, obtain essentially the same EOS parameter values as those in the previous study, and confirm the two important features for symmetry energy; a strong correlation between S0 and L, and the upper bound of L which is an increasing function of K0. The present results strongly support the prediction of the previous study that the matter radii of neutron-rich nuclei depend strongly on L while being almost independent of K0. This is a feature that will help to determine the L value via systematic measurements of nuclear size. (author)
Incompressibility of asymmetric nuclear matter
International Nuclear Information System (INIS)
Using an isospin- and momentum-dependent modified Gogny (MDI) interaction, the Skyrme-Hartree-Fock (SHF) approach, and a phenomenological modified Skyrme-like (MSL) model, we have studied the incompressibility Ksat(?) of isospin asymmetric nuclear matter at its saturation density. Our results show that in the expansion of Ksat(?) in powers of isospin asymmetry ?, i.e., Ksat(?) = K0 + Ksat,2?2 + Ksat,4?4 + O(?6), the magnitude of the 4th-order Ksat,4 parameter is generally small. The 2nd-order Ksat,2 parameter thus essentially characterizes the isospin dependence of the incompressibility of asymmetric nuclear matter at saturation density. Furthermore, the Ksat,2 can be expressed as Ksat,2 = Ksym – 6L – J0/K0 L in terms of the slope parameter L and the curvature parameter Ksym of the symmetry energy and the third-order derivative parameter J0 of the energy of symmetric nuclear matter at saturation density, and we find the higher order J0 contribution to Ksat,2 generally cannot be neglected. Also, we have found a linear correlation between Ksym and L as well as between J0/K0 and K0. Using these correlations together with the empirical constraints on K0 and L, the nuclear symmetry energy Esym(?0) at normal nuclear density, and the nucleon effective mass, we have obtained an estimated value of Ksat,2 = -370 ± 120 MeV for the 2nd-order parameter in the isospin asymmetry expansion of the incompressibility of asymmetric nuclear matter at its saturation density. (author)
Magnetic properties of strongly asymmetric nuclear matter
International Nuclear Information System (INIS)
We investigate stability of neutron matter containing a small proton admixture with respect to spin fluctuations. We establish conditions under which strongly asymmetric nuclear matter could acquire a permanent magnetization. It is shown that if the protons are localized, the system becomes unstable to spin fluctuations for arbitrarily weak proton-neutron spin interactions. For non-localized protons there exists a threshold value of the spin interaction above which the system can develop a spontaneous polarization. 12 refs., 2 figs. (author)
Response Function of Asymmetric Nuclear Matter
Takayanagi, Kazuo; Cheon, Taksu
1995-01-01
The charge longitudinal response function is examined in the framework of the random-phase approximation in an isospin-asymmetric nuclear matter where proton and neutron densities are different. This asymmetry changes the response through both the particle-hole interaction and the free particle-hole polarization propagator. We discuss these two effects on the response function on the basis of our numerical results in detail.
Symmetry energy coefficients for asymmetric nuclear matter
International Nuclear Information System (INIS)
Symmetry energy coefficients of asymmetric nuclear matter generalized are investigated as the inverse of nuclear matter polarizabilities with two different approaches. Firstly a general calculation shows they may depend on the neutron-proton asymmetry itself. The choice of particular prescriptions for the density fluctuations lead to certain isospin (n-p asymmetry) dependences of the polarizabilities. Secondly, with Skyrme type interactions, the static limit of the dynamical polarizability is investigated corresponding to the inverse symmetry energy coefficient which assumes different values at different asymmetries (and densities and temperatures). The symmetry energy coefficient (in the isovector channel) is found to increase as n-p asymmetries increase. The spin symmetry energy coefficient is also briefly investigated. (author)
Symmetry energy coefficients for asymmetric nuclear matter
Scientific Electronic Library Online (English)
Fábio L., Braghin.
2003-06-01
Full Text Available Symmetry energy coefficients of asymmetric nuclear matter generalized are investigated as the inverse of nuclear matter polarizabilities with two different approaches. Firstly a general calculation shows they may depend on the neutron-proton asymmetry itself. The choice of particular prescriptions f [...] or the density fluctuations lead to certain isospin (n-p asymmetry) dependences of the polarizabilities. Secondly, with Skyrme type interactions, the static limit of the dynamical polarizability is investigated corresponding to the inverse symmetry energy coefficient which assumes different values at different asymmetries (and densities and temperatures). The symmetry energy coefficient (in the isovector channel) is found to increase as n-p asymmetries increase. The spin symmetry energy coefficient is also briefly investigated.
Phase transitions in warm, asymmetric nuclear matter
International Nuclear Information System (INIS)
A relativistic mean-field model of nuclear matter with arbitrary proton fraction is studied at finite temperature. An analysis is performed of the liquid-gas phase transition in a system with two conserved charges (baryon number and isospin) using the stability conditions on the free energy, the conservation laws, and Gibbs' criteria for phase equilibrium. For a binary system with two phases, the coexistence surface (binodal) is two dimensional. The Maxwell construction through the phase-separation region is discussed, and it is shown that the stable configuration can be determined uniquely at every density. Moreover, because of the greater dimensionality of the binodal surface, the liquid-gas phase transition is continuous (second order by Ehrenfest's definition), rather than discontinuous (first order), as in familiar one-component systems. Using a mean-field equation of state calibrated to the properties of nuclear matter and finite nuclei, various phase-separation scenarios are considered. The model is then applied to the liquid-gas phase transition that may occur in the warm, dilute matter produced in energetic heavy-ion collisions. In asymmetric matter, instabilities that produce a liquid-gas phase separation arise from fluctuations in the proton concentration (chemical instability), rather than from fluctuations in the baryon density (mechanical instability)
Pseudo-Goldstone modes in isospin-asymmetric nuclear matter
International Nuclear Information System (INIS)
The authors analyze the chiral limit in dense isospin-asymmetric nuclear matter. It is shown that the pseudo-Goldstone modes in this system are qualitatively different from the case of isospin-symmetric matter
Sum rules and correlations in asymmetric nuclear matter
Rios Huguet, Arnau; Polls Martí, Artur; Müther, Herbert
2006-01-01
The neutron and proton single-particle spectral functions in asymmetric nuclear matter fulfill energy-weighted sum rules. The validity of these sum rules within the self-consistent Green's function approach is investigated. The various contributions to these sum rules and their convergence as a function of energy provide information about correlations induced by the realistic interaction between the nucleons. The study of the sum rules in asymmetric nuclear matter exhibits the isospin depende...
International Nuclear Information System (INIS)
In this paper, we calculate properties of the spin polarized asymmetrical nuclear matter and neutron star matter, using the lowest order constrained variational (LOCV) method with the AV18, Reid93, UV14, and AV14 potentials. According to our results, the spontaneous phase transition to a ferromagnetic state in the asymmetrical nuclear matter as well as neutron star matter do not occur
Damping of giant resonances in asymmetric nuclear matter
Morawetz, K; Walke, R
1999-01-01
The giant collective modes in asymmetric nuclear matter are investigated within a dynamic relaxation time approximation. We derive a coupled dispersion relation and show that two sources of coupling appear: (i) a coupling of isoscalar and isovector modes due to different mean-fields acting and (ii) an explicit new coupling in asymmetric matter due to collisional interaction. We show that the latter one is responsible for a new mode arising besides isovector and isoscalar modes.
Asymmetric nuclear matter in a modified quark meson coupling model
International Nuclear Information System (INIS)
In an earlier attempt we have successfully used this model in developing the nuclear equation of state and analysed various other bulk properties of symmetric nuclear matter with the dependence of quark masses. In the present work we want to apply the model to analyze asymmetric nuclear matter with the variation of the asymmetry parameter yp as well as analyze the effects of symmetry energy and the slope of the symmetry energy L
Short range correlations and spectral functions in asymmetric nuclear matter
International Nuclear Information System (INIS)
Dynamical correlations in asymmetric infinite nuclear matter are investigated in a transport theoretical approach. Self-energies due to short range correlations and their influence on the nucleon spectral functions are described in an approach accounting for a realistic treatment of mean-field dynamics and a self-consistently derived quasiparticle interaction. Landau-Migdal theory is used to derived the short range interaction from a phenomenological Skyrme energy density functional. The spectral functions in asymmetric nuclear matter are found to follow in their gross features closely the patterns observed previously in symmetric nuclear matter. An interesting sensitivity of dynamical self-energies and spectral functions on the momentum structure of the underlying interactions is found
Liquid-gas phase transition in asymmetric nuclear matter
International Nuclear Information System (INIS)
Liquid-gas phase transition in nuclear matter and in finite nuclei has been a subject of major interest in recent years. The Van-der-waal's behavior of pressure P versus density ? (or, equivalently chemical potential ? versus ?) is typical of a liquid gas phase transition and the critical temperature Tc is determined at which the isotherm has an inflection point. In the present work it is planned to study the liquid-gas phase transition in asymmetric nuclear matter as well as in finite nuclear systems in the framework of mean field theory using a finite range effective interaction
Neutron-proton mass difference in isospin asymmetric nuclear matter
Meißner, Ulf-G.; Rakhimov, A. M.; A. Wirzba(Institute for Advanced Simulation, Institut für Kernphysik, and Jülich Center for Hadron Physics, Forschungszentrum Jülich, D-52425 Jülich, Germany); Yakhshiev, U. T.
2007-01-01
Isospin-breaking effects in the baryonic sector are studied in the framework of a medium-modified Skyrme model. The neutron-proton mass difference in infinite, asymmetric nuclear matter is discussed. In order to describe the influence of the nuclear environment on the skyrmions, we include energy-dependent charged and neutral pion optical potentials in the s- and p-wave channels. The present approach predicts that the neutron-proton mass difference is mainly dictated by its ...
Neutron-proton mass difference in isospin asymmetric nuclear matter
Meißner, Ulf-G; Wirzba, A; Yakhshiev, U T
2007-01-01
Isospin-breaking effects in the baryonic sector are studied in the framework of a medium-modified Skyrme model. The neutron-proton mass difference in infinite, asymmetric nuclear matter is discussed. In order to describe the influence of the nuclear environment on the skyrmions, we include energy-dependent charged and neutral pion optical potentials in the s- and p-wave channels. The present approach predicts that the neutron-proton mass difference is mainly dictated by its strong part and that it strongly decreases in neutron matter.
Pairing effects on spinodal decomposition of asymmetric nuclear matter
Directory of Open Access Journals (Sweden)
Burrello S.
2015-01-01
Full Text Available We present an analysis framed in the general context of two-component fermionic systems subjected to pairing correlations. The study is conducted for unstable asymmetric nuclear matter at low temperature, along the clusterization process driven by spinodal instabilities. It is shown that, especially around the transition temperature from the superfluid to the normal phase, pairing correlations may have non-negligible effects on the isotopic features of the clusterized low-density matter, which could be of interest also in the astrophysical context.
Pairing effects on spinodal decomposition of asymmetric nuclear matter
Burrello, Stefano; Matera, Francesco
2013-01-01
We investigate the impact of pairing correlations on the behavior of unstable asymmetric nuclear matter at low temperature. We focus on the relative role of the pairing interaction, coupling nucleons of the same type (neutrons or protons), with respect to the symmetry potential, which enhances the neutron-proton attraction, along the clusterization process driven by spinodal instabilities. It is found that, especially at the transition temperature from the normal to the superfluid phase, pairing effects may induce significant variations in the isotopic content of the clusterized matter. This analysis is potentially useful to gather information on the temperature dependence of nuclear pairing and, in general, on the properties of clusterized low-density matter, of interest also in the astrophysical context.
3D2 pairing in asymmetric nuclear matter
International Nuclear Information System (INIS)
The superfluid 3D2 pairing instability in isospin-asymmetric nuclear matter is studied, using the Paris nucleon-nucleon interaction as an input. It is found that the critical temperature associated with the transition to the superfluid phase becomes strongly suppressed with increasing isospin asymmetry, and vanishes for asymmetry parameter values ? (?(nn-np)/(nn+np)) that are larger than several percent. It is shown that for neutron star models based on relativistic, field-theoretical equations of state, a large fraction of their interior may exist in a 3D2-paired superfluid phase. The implications of such a 3D2 superfluid in massive neutron stars is discussed with respect to observable pulsar phenomena. Another interesting phenomenon, discussed in the paper, concerns the numerical finding of two critical superfluid temperatures for a given density in the case of isospin-asymmetric matter. Using the BCS cut-off ansatz, a mathematical expression for the critical temperature is derived which confirms this finding analytically. (orig.)
Collective modes of asymmetric nuclear matter in quantum hadrodynamics
International Nuclear Information System (INIS)
We discuss a fully relativistic Landau Fermi liquid theory based on the quantum hadrodynamics effective field picture of nuclear matter. From the linearized kinetic equations we get the dispersion relations of the propagating collective modes. We focus our attention on the dynamical effects of the interplay between scalar and vector channel contributions. An interesting 'mirror' structure in the form of the dynamical response in the isoscalar-isovector degree of freedom is revealed, with a complete parallelism in the role respectively played by the compressibility and the symmetry energy. All that seems to support the introduction of an explicit coupling to the scalar-isovector channel of the nucleon-nucleon interaction. In particular we study the influence of this coupling (to a ?-meson-like effective field) on the collective response of asymmetric nuclear matter (ANM). Interesting contributions are found on the propagation of isovectorlike modes at normal density and on an expected smooth transition to isoscalarlike oscillations at high baryon density. Important 'chemical' effects on the neutron-proton structure of the mode are shown. For dilute ANM we have the isospin distillation mechanism of the unstable isoscalarlike oscillations, while at high baryon density we predict an almost pure neutron wave structure of the propagating sounds
On growth of spinodal instabilities in nuclear matter-II:asymmetric matter
Acar, F; Yilmaz, O; Gokalp, A
2015-01-01
As an extension of our previous work, the growth of density fluctuations in the spinodal region of charge asymmetric nuclear matter is investigated in the basis of the stochastic mean-field approach in the non-relativistic framework. A complete treatment of density correlation functions are presented by including collective modes and non-collective modes as well.
Effects of the equation of state of asymmetric nuclear matter in nuclear collisions
International Nuclear Information System (INIS)
60Ca + 60Ca and 197Au + 197Au collisions are studied with an extended version Antisymmetrized Molecular Dynamics (AMD-V), in order to investigate whether the reaction observables carry the information of the equation of state of the asymmetric nuclear matter. (author)
Extended Skyrme Equation of State in asymmetric nuclear matter
Davesne, D; Navarro, J
2015-01-01
We present a new equation of state for infinite systems (symmetric, asymmetric and neutron matter) based on an extended Skyrme functional constrained by microscopic Brueckner-Bethe-Goldstone results. The resulting equation of state reproduces with very good accuracy the main features of microscopic calculations and it is compatible with recent measurements of two times Solar-mass neutron stars. We provide all necessary analytical expressions to facilitate a quick numerical implementation of quantities of astrophysical interest.
Hyperons in a relativistic mean-field approach to asymmetric nuclear matter
Bunta, Juraj Kotulic; Gmuca, Stefan
2004-01-01
Relativistic mean-field theory with $\\delta$ meson, nonlinear isoscalar self-interactions and isoscalar-isovector cross interaction terms with parametrizations obtained to reproduce Dirac-Brueckner-Hartree-Fock calculations for nuclear matter is used to study asymmetric nuclear matter properties in $\\beta$-equilibrium, including hyperon degrees of freedom and (hidden) strange mesons. Influence of cross interaction on composition of hyperon matter and electron chemical potent...
International Nuclear Information System (INIS)
Using the Hugenholtz-Van Hove theorem, we derive general expressions for the quadratic and quartic symmetry energies in terms of the isoscalar and isovector parts of single-nucleon potentials in isospin asymmetric nuclear matter. These expressions are useful for gaining deeper insights into the microscopic origins of the uncertainties in our knowledge on nuclear symmetry energies especially at supra-saturation densities. As examples, the formalism is applied to two model single-nucleon potentials that are widely used in transport model simulations of heavy-ion reactions.
Thermodynamics of isospin-asymmetric nuclear matter from chiral effective field theory
Wellenhofer, Corbinian; Holt, Jeremy W.; Kaiser, Norbert
2015-07-01
The density and temperature dependence of the nuclear symmetry free energy is investigated using microscopic two- and three-body nuclear potentials constructed from chiral effective field theory. The nuclear force models and many-body methods are benchmarked to properties of isospin-symmetric nuclear matter in the vicinity of the saturation density as well as the virial expansion of the neutron matter equation of state at low fugacities. The free energy per particle of isospin-asymmetric nuclear matter is calculated assuming a quadratic dependence of the interaction contributions on the isospin asymmetry. The spinodal instability at subnuclear densities is examined in detail.
Nuclear superfluidity in isospin asymmetric matter within the Skyrme model
Aguirre, R.
2013-01-01
The phase diagram of the superfluid phase coupled to spin singlet (S=0) and isospin triplet (T=1) states in infinite nuclear matter is analyzed within the nonrelativistic Skyrme model. We use an approach that allows a unified and consistent treatment of the particle-hole and particle-particle channels. The gap equation is solved for the full range of accessible densities, isospin asymmetries, and temperatures. The characteristic features of each of the components Tz=0, +1, -...
Nucleon mean free path in asymmetric nuclear matter at finite temperature
International Nuclear Information System (INIS)
The nucleon mean free path in symmetric and asymmetric nuclear matter is investigated in the framework of the finite temperature Brueckner theory. The realistic Bonn B two-body nucleon–nucleon interaction in combination with a consistent microscopic three-body force is adopted in the calculations. The results of the nucleon mean free path at zero temperature are in good agreement with the experimental data. The temperature and density and isospin dependence of the mean free path are studied systematically in asymmetric nuclear matter. (paper)
A Time Dependent Local Isospin Density Approximation Study of Asymmetric Nuclear Matter
Lipparini, Enrico; Pederiva, Francesco
2013-01-01
The dynamic response of asymmetric nuclear matter is studied by using a Time-Dependent Local Isospin Density (TDLIDA) approximation approach. Calculations are based on a local density energy functional derived by an Auxiliary Field Diffusion Monte Carlo (AFDMC) calculation of bulk nuclear matter. Three types of excited states emerge: collective states, a continuum of quasi-particle-quasi-hole excitations and unstable solutions. These states are analyzed and discussed for dif...
Asymmetric nuclear matter in the relativistic mean field approach with vector cross-interaction
Bunta, Juraj Kotulic; Gmuca, Stefan
2003-01-01
Asymmetric nuclear matter is studied in the frame of relativistic mean-field theory, using scalar-isoscalar sigma, vector-isoscalar omega meson together with their selfinteractions, vector-isovector rho meson with its cross-interaction with omega meson too, and scalar-isovector delta meson as degrees of freedom. The model is used to parameterize the nuclear matter properties results calculated by more fundamental Dirac-Brueckner-Hartree-Fock theory and thus to provide an eff...
Hyperons in a relativistic mean-field approach to asymmetric nuclear matter
International Nuclear Information System (INIS)
Relativistic mean-field theory with ? mesons, nonlinear isoscalar self-interactions, and isoscalar-isovector cross interaction terms with parametrizations obtained to reproduce Dirac-Brueckner-Hartree-Fock calculations for nuclear matter is used to study asymmetric nuclear matter properties in ? equilibrium, including hyperon degrees of freedom and (hidden) strange mesons. The influence of cross interactions on the composition of hyperon matter and the electron chemical potential is examined. Softening of the nuclear equation of state by cross interactions results in a lowering of the hyperonization, although simultaneously enhancing a hyperon-induced decrease of the electron chemical potential, thus indicating a further shift of the kaon condensate occurrence to higher densities
Hyperons in a relativistic mean-field approach to asymmetric nuclear matter
Bunta, J K; Bunta, Juraj Kotulic; Gmuca, Stefan
2004-01-01
Relativistic mean-field theory with $\\delta$ meson, nonlinear isoscalar self-interactions and isoscalar-isovector cross interaction terms with parametrizations obtained to reproduce Dirac-Brueckner-Hartree-Fock calculations for nuclear matter is used to study asymmetric nuclear matter properties in $\\beta$-equilibrium, including hyperon degrees of freedom and (hidden) strange mesons. Influence of cross interaction on composition of hyperon matter and electron chemical potential is examined. Softening of nuclear equation of state by the cross interactions results in lowering of hyperonization, although simultaneously enhancing a hyperon-induced decrease of the electron chemical potential, thus indicating further shift of a kaon condensate occurence to higher densities.
Thermodynamics of isospin-asymmetric nuclear matter from chiral effective field theory
Wellenhofer, Corbinian; Kaiser, Norbert
2015-01-01
The density and temperature dependence of the nuclear symmetry free energy is investigated using microscopic two- and three-body nuclear potentials constructed from chiral effective field theory. The nuclear force models and many-body methods are benchmarked to properties of isospin-symmetric nuclear matter in the vicinity of the saturation density as well as the virial expansion of the neutron matter equation of state at low fugacities. The free energy per particle of nuclear matter with varying neutron-to-proton ratio is calculated assuming a quadratic dependence of the interaction contributions on the isospin asymmetry. The thermodynamic equation of state of isospin-asymmetric nuclear matter is examined in detail.
Asymmetric nuclear matter in the relativistic mean-field approach with vector cross interaction
International Nuclear Information System (INIS)
Asymmetric nuclear matter is studied in the frame of relativistic mean-field theory, using scalar-isoscalar ? , vector-isoscalar ? meson together with their self-interactions, vector-isovector ? meson with its cross interaction with ? meson too, and scalar-isovector ? meson as degrees of freedom. The model is used to parametrize the nuclear matter property results calculated by more fundamental Dirac-Brueckner-Hartree-Fock theory, and thus to provide an effective Dirac-Brueckner-Hartree-Fock model applicable also to finite nuclei. Vector ?-? cross interaction seems to be an useful degree of freedom for describing of the asymmetric nuclear matter, mostly due to its impact on density dependence of the symmetry energy
Asymmetric nuclear matter in the relativistic mean field approach with vector cross-interaction
Bunta, J K; Bunta, Juraj Kotulic; Gmuca, Stefan
2003-01-01
Asymmetric nuclear matter is studied in the frame of relativistic mean-field theory, using scalar-isoscalar sigma, vector-isoscalar omega meson together with their selfinteractions, vector-isovector rho meson with its cross-interaction with omega meson too, and scalar-isovector delta meson as degrees of freedom. The model is used to parameterize the nuclear matter properties results calculated by more fundamental Dirac-Brueckner-Hartree-Fock theory and thus to provide an effective DBHF model applicable also to finite nuclei. Vector omega-rho cross-interaction seems to be an useful degree of freedom for describing of the asymmetric nuclear matter, mostly due to its impact on density dependence of the symmetry energy.
Neutron-proton mass difference in isospin-asymmetric nuclear matter
Meißner, U.-G.; Rakhimov, A. M.; Wirzba, A.; Yakhshiev, U. T.
2007-06-01
Isospin-breaking effects in the baryonic sector are studied in the framework of a medium-modified Skyrme model. The neutron-proton mass difference in infinite, asymmetric nuclear matter is discussed. In order to describe the influence of the nuclear environment on the skyrmions, we include energy-dependent charged and neutral pion optical potentials in the s - and p -wave channels. The present approach predicts that the neutron-proton mass difference is mainly dictated by its strong part and that it strongly decreases in neutron matter.
Neutron-proton mass difference in isospin-asymmetric nuclear matter
Energy Technology Data Exchange (ETDEWEB)
Meissner, U.-G. [Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik (Theorie) (Germany); Forschungszentrum Juelich, Institut fuer Kernphysik (Theorie), Juelich (Germany); Rakhimov, A.M. [Academy of Sciences of Uzbekistan, Institute of Nuclear Physics, Tashkent-132 (Uzbekistan); Yonsei University, Institute of Physics and Applied Physics, Seoul (Korea); Wirzba, A. [Forschungszentrum Juelich, Institut fuer Kernphysik (Theorie), Juelich (Germany); Yakhshiev, U.T. [Forschungszentrum Juelich, Institut fuer Kernphysik (Theorie), Juelich (Germany); National University of Uzbekistan, Physics Department and Institute of Applied Physics, Tashkent-174 (Uzbekistan)
2007-06-15
Isospin-breaking effects in the baryonic sector are studied in the framework of a medium-modified Skyrme model. The neutron-proton mass difference in infinite, asymmetric nuclear matter is discussed. In order to describe the influence of the nuclear environment on the skyrmions, we include energy-dependent charged and neutral pion optical potentials in the s- and p-wave channels. The present approach predicts that the neutron-proton mass difference is mainly dictated by its strong part and that it strongly decreases in neutron matter. (orig.)
Rabhi, A.; Pérez-García, M.A.; Providência, C.; Vidaña, I
2014-01-01
We study the effect of a strong magnetic field on the proton and neutron spin polarization and magnetic susceptibility of asymmetric nuclear matter within a relativistic mean-field approach. It is shown that magnetic fields $B \\sim 10^{16} - 10^{17}$ G have already noticeable effects on the range of densities of interest for the study of the crust of a neutron star. Although the proton susceptibility is larger for weaker fields, the neutron susceptibility becomes of the same...
What can we learn from the instabilities of asymmetric nuclear matter?
International Nuclear Information System (INIS)
Based on a general approach to binary systems we show that in low density region asymmetric nuclear matter (ANM) is unstable only against isoscalarlike fluctuations. The physical meaning of the thermodynamical chemical and mechanical instabilities is related to the inequality relations verified by the strength of interaction among different components. Relevance of these results for bulk and neck fragmentation in the reaction 124 Sn + 124 Sn at 50 MeV/n is discussed. (authors)
Coexistence of phases in asymmetric nuclear matter under strong magnetic fields
Aguirre, R
2014-01-01
The equation of state of nuclear matter is strongly affected by the presence of a magnetic field. Here we study the equilibrium configuration of asymmetric nuclear matter for a wide range of densities, isospin composition, temperatures and magnetic fields. Special attention is paid to the low density and low temperature domain, where a thermodynamical instability exists. Neglecting fluctuations of the Coulomb force, a coexistence of phases is found under such conditions, even for extreme magnetic intensities. We describe the nuclear interaction by using the non--relativistic Skyrme potential model within a Hartree--Fock approach. We found that the coexistence of phases modifies the equilibrium configuration, masking most of the manifestations of the spin polarized matter. However, the compressibility and the magnetic susceptibility show clear signals of this fact. Thermal effects are significative for both quantities, mainly out of the coexistence region.
Lowest-order constrained variational calculation for hot asymmetric nuclear matter
Energy Technology Data Exchange (ETDEWEB)
Modarres, Majid [Centre for Theoretical Physics and Mathematics, AEOI, PO Box 11365-8486, Tehran (Iran, Islamic Republic of); Physics Department, Amir-Kabir University, Tehran (Iran, Islamic Republic of)
1997-08-01
The method of lowest-order constrained variational that reasonably predicts the nuclear matter saturation data is used to calculate the equation of state of asymmetric nuclear matter at finite temperature. The Reid soft-core potential with and without the N-{delta} interaction, which fits N-N scattering data, is taken as the nuclear Hamiltonian. The calculation is performed for a wide range of density, asymmetry parameter and nuclear temperature, which are of interest in heavy-ion collisions and astrophysics. Beside spin, isospin, total angular momentum and density dependence of the correlation functions, they are also arranged to depend on the temperature and asymmetry parameter of the system. The free energy, pressure, effective mass etc of asymmetric nuclear matter are calculated. It is shown that while the calculated symmetry coefficient defined in the semi-empirical mass formula is roughly constant and is near its empirical value at zero temperature, it depends on the proton-to-neutron ratio at finite temperature. Finally, the dependence of the liquid-vapour phase transition, as well as the effective mass dependence on the temperature and asymmetry parameter, is investigated. (author)
Asymmetric nuclear matter in a parity doublet model with hidden local symmetry
Motohiro, Yuichi; Kim, Youngman; Harada, Masayasu
2015-08-01
We construct a model to describe dense hadronic matter at zero and finite temperatures, based on the parity doublet model of DeTar and Kunihiro [C. E. DeTar and T. Kunihiro, Phys. Rev. D 39, 2805 (1989), 10.1103/PhysRevD.39.2805], including the isosinglet scalar meson ? as well as ? and ? mesons. We show that, by including a six-point interaction of the ? meson, the model reasonably reproduces the properties of normal nuclear matter with the chiral invariant nucleon mass m0 in the range from 500 to 900 MeV. Furthermore, we study the phase diagram based on the model, which shows that the value of the chiral condensate drops at the liquid-gas phase transition point and at the chiral phase transition point. We also study asymmetric nuclear matter and find that the first-order phase transition for the liquid-gas phase transition disappears in asymmetric matter and that the critical density for the chiral phase transition at nonzero density becomes smaller for larger asymmetry.
Asymmetric nuclear matter in a parity doublet model with hidden local symmetry
Motohiro, Yuichi; Harada, Masayasu
2015-01-01
We construct a model to describe dense hadronic matter at zero and finite temperature, based on the parity doublet model of DeTar and Kunihiro, with including the iso-singlet scalar meson $\\sigma$ as well as $\\rho$ and $\\omega$ mesons. We show that, by including a six-point interaction of $\\sigma$ meson, the model reasonably reproduces the properties of the normal nuclear matter with the chiral invariant nucleon mass $m_0$ in the range from $500~{\\rm MeV}$ to $900~{\\rm MeV}$. Furthermore, we study the phase diagram based on the model, which shows that the value of the chiral condensate drops at the liquid-gas phase transition point and at the chiral phase transition point. We also study asymmetric nuclear matter and find that the first order phase transition for the liquid-gas phase transition disappears in asymmetric matter and that the critical density for the chiral phase transition at non-zero density becomes smaller for larger asymmetry.
Graesser, Michael L.; Shoemaker, Ian M.; Vecchi, Luca
2011-01-01
In existing dark matter models with global symmetries the relic abundance of dark matter is either equal to that of anti-dark matter (thermal WIMP), or vastly larger, with essentially no remaining anti-dark matter (asymmetric dark matter). By exploring the consequences of a primordial asymmetry on the coupled dark matter and anti-dark matter Boltzmann equations we find large regions of parameter space that interpolate between these two extremes. Interestingly, this new asymm...
Thermodynamic instabilities in dense asymmetric nuclear matter and in compact stars
International Nuclear Information System (INIS)
We investigate the presence of thermodynamic instabilities in compressed asymmetric baryonic matter, reachable in high energy heavy ion collisions, and in the cold ?-stable compact stars. To this end we study the relativistic nuclear equation of state with the inclusion of ?-isobars and require the global conservation of baryon and electric charge numbers. Similarly to the low density nuclear liquid-gas phase transition, we show that a phase transition can occur in dense asymmetric nuclear matter and it is characterized by both mechanical instability (fluctuations on the baryon density) and by chemical-diffusive instability (fluctuations on the electric charge concentration). Such thermodynamic instabilities can imply a very different electric charge fraction Z/A in the coexisting phases during the phase transition and favoring an early formation of ?? particles with relevant phenomenological consequences in the physics of the protoneutron stars and compact stars. Finally, we discuss the possible co-existence of very compact and very massive compact stars in terms of two separate families: compact hadronic stars and very massive quark stars.
Kouvaris, Chris; Nielsen, Niklas Grønlund
2015-01-01
We study the possibility of asymmetric dark matter with self-interactions forming compact stable objects. We solve the Tolman-Oppenheimer-Volkoff equation and find the mass-radius relation of such "dark stars", their density profile and their Chandrasekhar mass limit. We consider fermionic asymmetric dark matter with Yukawa-type self-interactions appropriate for solving the well known problems of the collisionless dark matter paradigm. We find that in several cases the relat...
Kouvaris, Chris
2015-01-01
We study the possibility of asymmetric dark matter with self-interactions forming compact stable objects. We solve the Tolman-Oppenheimer-Volkoff equation and find the mass-radius relation of such "dark stars", their density profile and their Chandrasekhar mass limit. We consider fermionic asymmetric dark matter with Yukawa-type self-interactions appropriate for solving the well known problems of the collisionless dark matter paradigm. We find that in several cases the relativistic effects are significant.
International Nuclear Information System (INIS)
A phenomenological momentum dependent interaction (MDI) is considered to describe the equation of state (EOS) for isospin asymmetric nuclear matter (ANM), where the density dependence of the nuclear symmetry is the basic input. In this interaction, the symmetry energy shows soft dependence of density. Within the nonrelativistic mean field approach we calculate the nuclear matter fourth-order symmetry energy Esym,4(?). Our result shows that the value of Esym,4(?) at normal nuclear matter density ?0( = 0.161 fm-3) is less than 1 MeV conforming the empirical parabolic approximation to the EOS of ANM at ?0. Then the higher-order effects of the isospin asymmetry on the saturation density ?sat(?), binding energy per nucleon Ksat(?) and isobaric incompressibility Ksat(?) of ANM is being studied, where ? = [?n - ?p]/? is the isospin asymmetry. We have found that the fourth-order isospin asymmetry ? cannot be neglected, while calculating these quantities. Hence the second-order Ksat,2 parameter basically characterizes the isospin dependence of the incompressibility of ANM at saturation density. (author)
Finite size effects in liquid-gas phase transition of asymmetric nuclear matter
International Nuclear Information System (INIS)
Full text: Since the nuclear equation of state has been studied in astrophysical context as an element of neutron star or super-nova theories - a call for an evidence was produced in experimental nuclear physics. Heavy-ion collisions became a tool of study on thermodynamic properties of nuclear matter. A particular interest has been inspired here by critical behavior of nuclear systems, as a phase transition of liquid-gas type. A lot of efforts was put to obtain an experimental evidence of such a phenomenon in heavy-ion collisions. With the use of radioactive beams and high performance identification systems in a near future it will be possible to extend experimental investigation to asymmetric nuclear systems, where neutron-to-proton ratio is far from the stability line. This experimental development needs a corresponding extension of theoretical studies. To obtain a complete theory of the liquid-gas phase transition in small nuclear systems, produced in violent heavy-ion collisions, one should take into account two facts. First, that the nuclear matter forming nuclei is composed of protons and neutrons; this complicates the formalism of phase transitions because one has to deal with two separate, proton and neutron, densities and chemical potentials. The second and more important is that the surface effects are very strong in a system composed of a few hundreds of nucleons. This point is especially difficult to hold, because surface becomes an additional, independen surface becomes an additional, independent state parameter, depending strongly on the geometrical configuration of the system, and introducing a non-local term in the equation of state. In this presentation we follow the recent calculation by Lee and Mekjian on the finite-size effects in small (A = 102 -103) asymmetric nuclear systems. A zero-range isospin-dependent Skyrme force is used to obtain a density and isospin dependent potential. The potential is then completed by additional terms giving contributions from surface and Coulomb energies. Taking into account the particle number conservation and assuming a specific geometrical configuration we introduce different and more precise formulae for these terms, keeping the main idea presented in unchanged. Applying a mean-field theory of nuclear matter, pressure and chemical potentials are obtained and used to resolve Gibbs conditions, giving properties of gas and liquid phases. (Author)
Variational study for the equation of state of asymmetric nuclear matter at finite temperatures
Togashi, H; 10.1016/j.nuclphysa.2013.02.014
2013-01-01
An equation of state (EOS) for uniform asymmetric nuclear matter (ANM) is constructed at zero and finite temperatures by the variational method starting from the nuclear Hamiltonian that is composed of the Argonne v18 and Urbana IX potentials. At zero temperature, the two-body energy is calculated with the Jastrow wave function in the two-body cluster approximation which is supplemented by Mayer's condition and the healing-distance condition so as to reproduce the result by Akmal, Pandharipande and Ravenhall. The energy caused by the three-body force is treated somewhat phenomenologically so that the total energy reproduces the empirical saturation conditions. The masses and radii of neutron stars obtained with the EOS are consistent with recent observational data. At finite temperatures, thermodynamic quantities such as free energy, internal energy, entropy, pressure and chemical potentials are calculated with an extension of the method by Schmidt and Pandharipande. The validity of the frozen-correlation app...
Rabhi, A; Providência, C; Vidaña, I
2014-01-01
We study the effect of a strong magnetic field on the proton and neutron spin polarization and magnetic susceptibility of asymmetric nuclear matter within a relativistic mean-field approach. It is shown that magnetic fields $B \\sim 10^{16} - 10^{17}$ G have already noticeable effects on the range of densities of interest for the study of the crust of a neutron star. Although the proton susceptibility is larger for weaker fields, the neutron susceptibility becomes of the same order or even larger for small proton fractions and subsaturation densities for $B > 10^{16}$ G. We expect that neutron superfluidity in the crust will be affected by the presence of magnetic fields.
Variational study for the equation of state of asymmetric nuclear matter at finite temperatures
Energy Technology Data Exchange (ETDEWEB)
Togashi, H., E-mail: hajime_togashi@ruri.waseda.jp [Department of Pure and Applied Physics, Graduate School of Advanced Science and Engineering, Waseda University, 3-4-1 Okubo Shinjuku-ku, Tokyo 169-8555 (Japan); Takano, M. [Department of Pure and Applied Physics, Graduate School of Advanced Science and Engineering, Waseda University, 3-4-1 Okubo Shinjuku-ku, Tokyo 169-8555 (Japan); Research Institute for Science and Engineering, Waseda University, 3-4-1 Okubo Shinjuku-ku, Tokyo 169-8555 (Japan)
2013-03-15
An equation of state (EOS) for uniform asymmetric nuclear matter (ANM) is constructed at zero and finite temperatures by the variational method starting from the nuclear Hamiltonian that is composed of the Argonne v18 and Urbana IX potentials. At zero temperature, the two-body energy is calculated with the Jastrow wave function in the two-body cluster approximation which is supplemented by Mayer's condition and the healing-distance condition so as to reproduce the result by Akmal, Pandharipande and Ravenhall. The energy caused by the three-body force is treated somewhat phenomenologically so that the total energy reproduces the empirical saturation conditions. The masses and radii of neutron stars obtained with the EOS are consistent with recent observational data. At finite temperatures, thermodynamic quantities such as free energy, internal energy, entropy, pressure and chemical potentials are calculated with an extension of the method by Schmidt and Pandharipande. The validity of the frozen-correlation approximation employed in this work is confirmed as compared with the result of the fully minimized calculation. The quadratic proton-fraction-dependence of the energy of ANM is confirmed at zero temperature, whereas the free energy of ANM deviates from the quadratic proton-fraction-dependence markedly at finite temperatures. The obtained EOS of ANM will be an important ingredient of a new nuclear EOS for supernova numerical simulations.
Farina, Marco
2015-01-01
We study a natural implementation of Asymmetric Dark Matter in Twin Higgs models. The mirroring of the Standard Model strong sector suggests that a twin baryon with mass around 5 GeV is a natural dark matter candidate once a twin baryon number asymmetry comparable to the SM asymmetry is generated. We explore twin baryon dark matter in two different scenarios, one with minimal content in the twin sector and one with a complete copy of the SM, including a light twin photon. Th...
Gulshan, Mahajan; Dhiman, Shashi K.
2011-01-01
The effect of temperature and density dependence of the asymmetric nuclear matter properties is studied within the extended relativistic mean field (ERMF) model, which includes the contribution from the self and mixed interaction terms by using different parametrizations obtained by varying the neutron skin thickness $\\Delta$r and $\\omega$-meson self-coupling ($\\zeta$). We observed that the symmetry energy and its slope and incompressibility coefficients decrease with increa...
Asymmetric dense matter in holographic QCD
Directory of Open Access Journals (Sweden)
Shin Ik Jae
2012-02-01
Full Text Available We study asymmetric dense matter in holographic QCD.We construct asymmetric dense matter by considering two quark flavor branes with dierent quark masses in a D4/D6/D6 model. To calculate the symmetry energy in nuclear matter, we consider two quarks with equal masses and observe that the symmetry energy increases with the total charge showing the stiff dependence. This behavior is universal in the sense that the result is independent of parameters in the model. We also study strange (or hyperon matter with one light and one intermediate mass quarks. In addition to the vacuum properties of asymmetric matter, we calculate meson masses in asymmetric dense matter and discuss our results in the light of in-medium kaon masses.
Farina, Marco
2015-01-01
We study a natural implementation of Asymmetric Dark Matter in Twin Higgs models. The mirroring of the Standard Model strong sector suggests that a twin baryon with mass around 5 GeV is a natural dark matter candidate once a twin baryon number asymmetry comparable to the SM asymmetry is generated. We explore twin baryon dark matter in two different scenarios, one with minimal content in the twin sector and one with a complete copy of the SM, including a light twin photon. The essential requirements for successful thermal history are presented, and in doing so we address some of the cosmological issues common to many Twin Higgs models. The required interactions we introduce predict signatures at direct detection experiments and at the LHC.
Asymmetric Dark Matter from Leptogenesis
Falkowski, Adam; Joshua T. Ruderman; Volansky, Tomer
2011-01-01
We present a new realization of asymmetric dark matter in which the dark matter and lepton asymmetries are generated simultaneously through two-sector leptogenesis. The right-handed neutrinos couple both to the Standard Model and to a hidden sector where the dark matter resides. This framework explains the lepton asymmetry, dark matter abundance and neutrino masses all at once. In contrast to previous realizations of asymmetric dark matter, the model allows for a wide range ...
Critical temperature for ?-condensation in asymmetric nuclear matter: the astrophysical context
International Nuclear Information System (INIS)
The critical temperature for ?-particle condensation in nuclear matter with Fermi surface imbalance between protons and neutrons is determined. The in-medium four-body Schroedinger equation, generalizing the Thouless criterion of the BCS transition, is applied using a Hartree-Fock wave function for the quartet projected onto zero total momentum in matter with different chemical potentials for protons and neutrons. (author)
Minimal asymmetric dark matter
Directory of Open Access Journals (Sweden)
Sofiane M. Boucenna
2015-09-01
Full Text Available In the early Universe, any particle carrying a conserved quantum number and in chemical equilibrium with the thermal bath will unavoidably inherit a particle–antiparticle asymmetry. A new particle of this type, if stable, would represent a candidate for asymmetric dark matter (DM with an asymmetry directly related to the baryon asymmetry. We study this possibility for a minimal DM sector constituted by just one (generic SU(2L multiplet ? carrying hypercharge, assuming that at temperatures above the electroweak phase transition an effective operator enforces chemical equilibrium between ? and the Higgs boson. We argue that limits from DM direct detection searches severely constrain this scenario, leaving as the only possibilities scalar or fermion multiplets with hypercharge y=1, preferentially quintuplets or larger SU(2 representations, and with a mass in the few TeV range.
Minimal asymmetric dark matter
Boucenna, Sofiane M.; Krauss, Martin B.; Nardi, Enrico
2015-09-01
In the early Universe, any particle carrying a conserved quantum number and in chemical equilibrium with the thermal bath will unavoidably inherit a particle-antiparticle asymmetry. A new particle of this type, if stable, would represent a candidate for asymmetric dark matter (DM) with an asymmetry directly related to the baryon asymmetry. We study this possibility for a minimal DM sector constituted by just one (generic) SU (2)L multiplet ? carrying hypercharge, assuming that at temperatures above the electroweak phase transition an effective operator enforces chemical equilibrium between ? and the Higgs boson. We argue that limits from DM direct detection searches severely constrain this scenario, leaving as the only possibilities scalar or fermion multiplets with hypercharge y = 1, preferentially quintuplets or larger SU (2) representations, and with a mass in the few TeV range.
Minimal Asymmetric Dark Matter
Boucenna, Sofiane M; Nardi, Enrico
2015-01-01
In the early Universe, any particle carrying a conserved quantum number and in chemical equilibrium with the thermal bath will unavoidably inherit a particle-antiparticle asymmetry. A new particle of this type, if stable, would represent a candidate for asymmetric dark matter (DM) with an asymmetry directly related to the baryon asymmetry. We study this possibility for a minimal DM sector constituted by just one (generic) $SU(2)_L$ multiplet $\\chi$ carrying hypercharge, assuming that at temperatures above the electroweak phase transition an effective operator enforces chemical equilibrium between $\\chi$ and the Higgs boson. We argue that limits from DM direct detection searches severely constrain this scenario, ruling out the possibility of scalar multiplets, and leaving as the only possibilities fermion DM with hypercharge $y = 1/2$ and $y = 1$ with a mass in the few TeV range.
Originally Asymmetric Dark Matter
Okada, Nobuchika; Seto, Osamu(Department of Life Science and Technology, Hokkai-Gakuen University, Sapporo, 062-8605, Japan)
2012-01-01
We propose a scenario with a fermion dark matter, where the dark matter particle used to be the Dirac fermion, but it takes the form of the Majorana fermion at a late time. The relic number density of the dark matter is determined by the dark matter asymmetry generated through the same mechanism as leptogenesis when the dark matter was the Dirac fermion. After efficient dark matter annihilation processes have frozen out, a phase transition of a scalar field takes place and g...
Gulshan, Mahajan; 10.1103/PhysRevC.84.045804
2011-01-01
The effect of temperature and density dependence of the asymmetric nuclear matter properties is studied within the extended relativistic mean field (ERMF) model, which includes the contribution from the self and mixed interaction terms by using different parametrizations obtained by varying the neutron skin thickness $\\Delta$r and $\\omega$-meson self-coupling ($\\zeta$). We observed that the symmetry energy and its slope and incompressibility coefficients decrease with increasing temperatures up to saturation densities. The ERMF parametrizations were employed to obtain a new set of equations of state (EOS) of the protoneutron star (PNS) with and without inclusion of hyperons. In our calculations, in comparison with cold compact stars, we obtained that the gravitational mass of the protoneutron star with and without hyperons increased by $\\sim 0.4M_{\\odot}$ and its radius increased by $\\sim 3$km. Whereas in case of the rotating PNS, the mass shedding limit decreased with increasing temperature, and this suggest...
Originally Asymmetric Dark Matter
Okada, Nobuchika
2012-01-01
We propose a scenario with a fermion dark matter, where the dark matter particle used to be the Dirac fermion, but it takes the form of the Majorana fermion at a late time. The relic number density of the dark matter is determined by the dark matter asymmetry generated through the same mechanism as leptogenesis when the dark matter was the Dirac fermion. After efficient dark matter annihilation processes have frozen out, a phase transition of a scalar field takes place and generates Majorana mass terms to turn the dark matter particle into the Majorana fermion. In order to address this scenario in detail, we propose two simple models. The first one is based on the Standard Model (SM) gauge group and the dark matter originates the $SU(2)_L$ doublet Dirac fermion, analogous to the Higgsino-like neutralino in supersymmetric models. We estimate the spin-independent/dependent elastic scattering cross sections of this late-time Majorana dark matter with a proton and find the possibility to discover it by the direct...
International Nuclear Information System (INIS)
We consider a simple class of models in which the relic density of dark matter is determined by the baryon asymmetry of the Universe. In these models a B-L asymmetry generated at high temperatures is transferred to the dark matter, which is charged under B-L. The interactions that transfer the asymmetry decouple at temperatures above the dark matter mass, freezing in a dark matter asymmetry of order the baryon asymmetry. This explains the observed relation between the baryon and dark matter densities for the dark matter mass in the range 5-15 GeV. The symmetric component of the dark matter can annihilate efficiently to light pseudoscalar Higgs particles a or via t-channel exchange of new scalar doublets. The first possibility allows for h0?aa decays, while the second predicts a light charged Higgs-like scalar decaying to ??. Direct detection can arise from Higgs exchange in the first model or a nonzero magnetic moment in the second. In supersymmetric models, the would-be lightest supersymmetric partner can decay into pairs of dark matter particles plus standard model particles, possibly with displaced vertices.
Asymmetric condensed dark matter
Aguirre, Anthony
2015-01-01
We explore the viability of a boson dark matter candidate with an asymmetry between the number densities of particles and antiparticles. A simple thermal field theory analysis confirms that, under certain general conditions, this component would develop a Bose-Einstein condensate in the early universe that, for appropriate model parameters, could survive the ensuing cosmological evolution until now. The condensation of a dark matter component in equilibrium with the thermal plasma is a relativistic process, hence the amount of matter dictated by the charge asymmetry is complemented by a hot relic density frozen out at the time of decoupling. Contrary to the case of ordinary WIMPs, dark matter particles in a condensate can be very light, $10^{-22}\\,{\\rm eV} \\lesssim m \\lesssim 10^2\\,{\\rm eV}$; the lower limit arises from constraints on small-scale structure formation, while the upper bound ensures that the density from thermal relics is not too large. Big-Bang nucleosynthesis constrains the temperature of deco...
Stable Bound States of Asymmetric Dark Matter
Wise, Mark B.; Zhang, Yue
2014-01-01
The simplest renormalizable effective field theories with asymmetric dark matter bound states contain two additional gauge singlet fields one being the dark matter and the other a mediator particle that the dark matter annihilates into. We examine the physics of one such model with a Dirac fermion as the dark matter and a real scalar mediator. For a range of parameters the Yukawa coupling of the dark matter to the mediator gives rise to stable asymmetric dark matter bound st...
Asymmetric dark matter and effective operators
International Nuclear Information System (INIS)
In order to annihilate in the early Universe to levels well below the measured dark matter density, asymmetric dark matter must possess large couplings to the standard model. In this paper, we consider effective operators which allow asymmetric dark matter to annihilate into quarks. In addition to a bound from requiring sufficient annihilation, the energy scale of such operators can be constrained by limits from direct detection and monojet searches at colliders. We show that the allowed parameter space for these operators is highly constrained, leading to nontrivial requirements that any model of asymmetric dark matter must satisfy.
Aidala, C; Akiba, Y; Akimoto, R; Alexander, J; Aoki, K; Apadula, N; Asano, H; Atomssa, E T; Awes, T C; Azmoun, B; Babintsev, V; Bai, M; Bai, X; Bannier, B; Barish, K N; Bathe, S; Baublis, V; Baumann, C; Baumgart, S; Bazilevsky, A; Beaumier, M; Belmont, R; Berdnikov, A; Berdnikov, Y; Bing, X; Black, D; Blau, D S; Bok, J; Boyle, K; Brooks, M L; Bryslawskyj, J; Buesching, H; Bumazhnov, V; Butsyk, S; Campbell, S; Chen, C -H; Chi, C Y; Chiu, M; Choi, I J; Choi, J B; Choi, S; Christiansen, P; Chujo, T; Cianciolo, V; Cole, B A; Cronin, N; Crossette, N; Csanád, M; Csörg?, T; Datta, A; Daugherity, M S; David, G; Dehmelt, K; Denisov, A; Deshpande, A; Desmond, E J; Ding, L; Do, J H; Drapier, O; Drees, A; Drees, K A; Durham, J M; Durum, A; D'Orazio, L; Engelmore, T; Enokizono, A; Esumi, S; Eyser, K O; Fadem, B; Fields, D E; Finger, M; Finger,, M; Fleuret, F; Fokin, S L; Frantz, J E; Franz, A; Frawley, A D; Fukao, Y; Gainey, K; Gal, C; Garg, P; Garishvili, A; Garishvili, I; Giordano, F; Glenn, A; Gong, X; Gonin, M; Goto, Y; de Cassagnac, R Granier; Grau, N; Greene, S V; Perdekamp, M Grosse; Gu, Y; Gunji, T; Guragain, H; Haggerty, J S; Hahn, K I; Hamagaki, H; Hanks, J; Hashimoto, K; Hayano, R; He, X; Hemmick, T K; Hester, T; Hill, J C; Hollis, R S; Homma, K; Hong, B; Hoshino, T; Huang, J; Huang, S; Ichihara, T; Ikeda, Y; Imai, K; Imazu, Y; Inaba, M; Iordanova, A; Isenhower, D; Isinhue, A; Ivanishchev, D; Jacak, B V; Jeon, S J; Jezghani, M; Jia, J; Jiang, X; Johnson, B M; Joo, K S; Jouan, D; Jumper, D S; Kamin, J; Kanda, S; Kang, B H; Kang, J H; Kang, J S; Kapustinsky, J; Kawall, D; Kazantsev, A V; Key, J A; Khachatryan, V; Khandai, P K; Khanzadeev, A; Kijima, K M; Kim, C; Kim, D J; Kim, E -J; Kim, Y -J; Kim, Y K; Kistenev, E; Klatsky, J; Kleinjan, D; Kline, P; Koblesky, T; Kofarago, M; Komkov, B; Koster, J; Kotchetkov, D; Kotov, D; Krizek, F; Kurita, K; Kurosawa, M; Kwon, Y; Lacey, R; Lai, Y S; Lajoie, J G; Lebedev, A; Lee, D M; Lee, G H; Lee, J; Lee, K B; Lee, K S; Lee, S H; Leitch, M J; Leitgab, M; Lewis, B; Li, X; Lim, S H; Liu, M X; Lynch, D; Maguire, C F; Makdisi, Y I; Makek, M; Manion, A; Manko, V I; Mannel, E; Maruyama, T; McCumber, M; McGaughey, P L; McGlinchey, D; McKinney, C; Meles, A; Mendoza, M; Meredith, B; Miake, Y; Mibe, T; Mignerey, A C; Milov, A; Mishra, D K; Mitchell, J T; Miyasaka, S; Mizuno, S; Mohanty, A K; Morrison, D P; Moskowitz, M; Moukhanova, T V; Murakami, T; Murata, J; Nagae, T; Nagamiya, S; Nagle, J L; Nagy, M I; Nakagawa, I; Nakamiya, Y; Nakamura, K R; Nakamura, T; Nakano, K; Nattrass, C; Netrakanti, P K; Nihashi, M; Niida, T; Nouicer, R; Novak, T; Novitzky, N; Nyanin, A S; O'Brien, E; Ogilvie, C A; Oide, H; Okada, K; Oskarsson, A; Ozawa, K; Pak, R; Pantuev, V; Papavassiliou, V; Park, I H; Park, S; Park, S K; Pate, S F; Patel, L; Peng, J -C; Perepelitsa, D; Perera, G D N; Peressounko, D Yu; Perry, J; Petti, R; Pinkenburg, C; Pisani, R P; Purschke, M L; Qu, H; Rak, J; Ravinovich, I; Read, K F; Reynolds, D; Riabov, V; Riabov, Y; Richardson, E; Riveli, N; Roach, D; Rolnick, S D; Rosati, M; Ryu, M S; Sahlmueller, B; Saito, N; Sakaguchi, T; Sako, H; Samsonov, V; Sarsour, M; Sato, S; Sawada, S; Sedgwick, K; Seele, J; Seidl, R; Sekiguchi, Y; Sen, A; Seto, R; Sett, P; Sharma, D; Shaver, A; Shein, I; Shibata, T -A; Shigaki, K; Shimomura, M; Shoji, K; Shukla, P; Sickles, A; Silva, C L; Silvermyr, D; Singh, B K; Singh, C P; Singh, V; Skolnik, M; Slune?ka, M; Solano, S; Soltz, R A; Sondheim, W E; Sorensen, S P; Soumya, M; Sourikova, I V; Stankus, P W; Steinberg, P; Stenlund, E; Stepanov, M; Ster, A; Stoll, S P; Stone, M R; Sugitate, T; Sukhanov, A; Sun, J; Takahara, A; Taketani, A; Tanida, K; Tannenbaum, M J; Tarafdar, S; Taranenko, A; Tennant, E; Timilsina, A; Todoroki, T; Tomášek, M; Torii, H; Towell, R S; Tserruya, I; van Hecke, H W; Vargyas, M; Vazquez-Zambrano, E; Veicht, A; Velkovska, J; Vértesi, R; Virius, M; Vrba, V; Vznuzdaev, E; Wang, X R; Watanabe, D; Watanabe, K; Watanabe, Y; Watanabe, Y S; Wei, F; Whitaker, S; Wolin, S; Woody, C L; Wysocki, M; Yamaguchi, Y L; Yanovich, A; Yokkaichi, S; Yoon, I; You, Z; Younus, I; Yushmanov, I E; Zajc, W A; Zelenski, A; Zhou, S
2014-01-01
We report on $J/\\psi$ production from asymmetric Cu+Au heavy-ion collisions at $\\sqrt{s_{_{NN}}}$=200 GeV at the Relativistic Heavy Ion Collider at both forward (Cu-going direction) and backward (Au-going direction) rapidities. The nuclear modification of $J/\\psi$ yields in Cu$+$Au collisions in the Au-going direction is found to be comparable to that in Au$+$Au collisions when plotted as a function of the number of participating nucleons. In the Cu-going direction, $J/\\psi$ production shows a stronger suppression. This difference is comparable in magnitude and has the same sign as the difference expected from shadowing effects due to stronger low-$x$ gluon suppression in the larger Au nucleus. The relative suppression is opposite to that expected from hot nuclear matter dissociation, since a higher energy density is expected in the Au-going direction.
Twin Higgs Asymmetric Dark Matter
García, Isabel García; March-Russell, John
2015-01-01
We study Asymmetric Dark Matter (ADM) in the context of the minimal (Fraternal) Twin Higgs solution to the little hierarchy problem, with a twin sector with gauged $SU(3)' \\times SU(2)'$, a twin Higgs, and only third generation twin fermions. Naturalness requires the QCD$^\\prime$ scale $\\Lambda'_{\\rm QCD} \\simeq 0.5 - 20 \\ {\\rm GeV}$, and $t'$ to be heavy. We focus on the light $b'$ quark regime, $m_{b'} \\lesssim \\Lambda'_{\\rm QCD}$, where QCD$^\\prime$ is characterised by a single scale $\\Lambda'_{\\rm QCD}$ with no light pions. A twin baryon number asymmetry leads to a successful DM candidate: the spin-3/2 twin baryon, $\\Delta' \\sim b'b'b'$, with a dynamically determined mass ($\\sim 5 \\Lambda'_{\\rm QCD}$) in the preferred range for the DM-to-baryon ratio $\\Omega_{\\rm DM}/\\Omega_{\\rm baryon} \\simeq 5$. Gauging the $U(1)'$ group leads to twin atoms ($\\Delta'$ - $\\bar {\\tau'}$ bound states) that are successful ADM candidates in significant regions of parameter space, sometimes with observable changes to DM halo ...
Phenomenological approach to nuclei and nuclear matter
International Nuclear Information System (INIS)
Neutron-rich nuclei and asymmetric nuclear matter are studied using a phenomenological macroscopic nuclear model paying special attention to the saturation condition of asymmetric nuclear matter. An interesting conclusion of this study is that the density derivative of symmetry energy at the nuclear density controls not only the masses and sizes of laboratory neutron-rich nuclei but also the core-crust boundary density of neutron stars and existence of pasta nuclei in the neutron-star crust. (author)
DAMA annual modulation effect and asymmetric mirror matter
Addazi, A; Bernabei, R; Belli, P; Cappella, F; Cerulli, R; Incicchitti, A
2015-01-01
The long-standing model-independent annual modulation effect measured by the DAMA Collaboration is examined in the framework of asymmetric mirror dark matter interacting with target nuclei in the detector via the kinetic mixing between mirror and ordinary photons. The allowed physical ranges for the kinetic mixing parameter are obtained taking into account various existing uncertainties in nuclear and particle physics quantities as well as in the density and velocity distributions of dark matter.
Asymmetric dark matter from hidden sector baryogenesis
Energy Technology Data Exchange (ETDEWEB)
Dutta, Bhaskar [Department of Physics and Astronomy, Mitchell Institute for Fundamental Physics, Texas A and M University, College Station, TX 77843 (United States); Kumar, Jason, E-mail: jkumar@hawaii.edu [Department of Physics and Astronomy, University of Hawai' i, Honolulu, HI 96822 (United States)
2011-05-23
We consider the production of asymmetric dark matter during hidden sector baryogenesis. We consider a particular supersymmetric model where the dark matter candidate has a number density approximately equal to the baryon number density, with a mass of the same scale as the b, c and {tau}. Both baryon asymmetry and dark matter are created at the same time in this model. We describe collider and direct detection signatures of this model.
Isospin violating dark matter being asymmetric
Okada, Nobuchika
2013-01-01
The isospin violating dark matter (IVDM) scenario offers an interesting possibility to reconcile conflicting results among direct dark matter search experiments for a mass range around 10 GeV. We consider two simple renormalizable IVDM models with a complex scalar dark matter and a Dirac fermion dark matter, respectively, whose stability is ensured by the conservation of "dark matter number". Although both models successfully work as the IVDM scenario with destructive interference between effective couplings to proton and neutron, the dark matter annihilation cross section is found to exceed the cosmological/astrophysical upper bounds. Then, we propose a simple scenario to reconcile the IVDM scenario with the cosmological/astrophysical bounds, namely, the IVDM being asymmetric. Assuming a suitable amount of dark matter asymmetry has been generated in the early Universe, the annihilation cross section beyond the cosmological/astrophysical upper bound nicely works to dramatically reduce the anti-dark matter rel...
DAMA annual modulation effect and asymmetric mirror matter
Addazi, A.; Berezhiani, Z.; Bernabei, R; Belli, P; Cappella, F.; Cerulli, R.; Incicchitti, A.
2015-01-01
The long-standing model-independent annual modulation effect measured by the DAMA Collaboration is examined in the framework of asymmetric mirror dark matter interacting with target nuclei in the detector via the kinetic mixing between mirror and ordinary photons. The allowed physical ranges for the kinetic mixing parameter are obtained taking into account various existing uncertainties in nuclear and particle physics quantities as well as in the density and velocity distrib...
Indirect Detection of Self-Interacting Asymmetric Dark Matter
Pearce, Lauren; Kusenko, Alexander
2013-01-01
Self-interacting dark matter resolves the issue of cuspy profiles that appear in non-interacting cold dark matter simluations; it may additionally resolve the so-called "too big to fail" problem in structure formation. Asymmetric dark matter provides a natural explanation of the comparable densities of baryonic matter and dark matter. In this paper, we discuss unique indirect detection signals produced by a minimal model of self-interacting asymmetric scalar dark matter. Thr...
Asymmetric dark matter and effective number of neutrinos
Kitabayashi, Teruyuki
2015-01-01
We study the effect of the MeV-scale asymmetric dark matter annihilation on the effective number of neutrinos $N_{\\rm eff}$ at the epoch of the big bang nucleosynthesis. If the asymmetric dark matter $\\chi$ couples more strongly to the neutrinos $\
Asymmetric Dark Matter and Dark Radiation
International Nuclear Information System (INIS)
Asymmetric Dark Matter (ADM) models invoke a particle-antiparticle asymmetry, similar to the one observed in the Baryon sector, to account for the Dark Matter (DM) abundance. Both asymmetries are usually generated by the same mechanism and generally related, thus predicting DM masses around 5 GeV in order to obtain the correct density. The main challenge for successful models is to ensure efficient annihilation of the thermally produced symmetric component of such a light DM candidate without violating constraints from collider or direct searches. A common way to overcome this involves a light mediator, into which DM can efficiently annihilate and which subsequently decays into Standard Model particles. Here we explore the scenario where the light mediator decays instead into lighter degrees of freedom in the dark sector that act as radiation in the early Universe. While this assumption makes indirect DM searches challenging, it leads to signals of extra radiation at BBN and CMB. Under certain conditions, precise measurements of the number of relativistic species, such as those expected from the Planck satellite, can provide information on the structure of the dark sector. We also discuss the constraints of the interactions between DM and Dark Radiation from their imprint in the matter power spectrum
Fixed-Velocity Chiral Sum Rules for Nuclear Matter
Cohen, Thomas D.; Broniowski, Wojciech
1997-01-01
Infinite sets of sum rules involving the excitations of infinite nuclear matter are derived using only completeness, the current algebra implicit in QCD, and relativistic covariance. The sum rules can be used for isospin-asymmetric nuclear matter, including neutron matter. They relate the chiral condensate and the isospin density to weighted sums over states with fixed velocity relative to the nuclear matter ground state.
Nucleon properties in nuclear matter
Yakhshiev, Ulugbek
2011-01-01
We present recent studies on the effective mass of the nucleon in infinite and homogeneous nuclear matter and its relation to nuclear matter properties within the framework of the in-medium modified Skyrme model. Medium modifications are achieved by introducing optical potential for pion fields and parametrization of the Skyrme parameter in nuclear medium. The present approach is phenomenologically well justified by pion physics in nuclear matter and describe successfully bulk nuclear matter properties.
Nucleon Properties in Nuclear Matter
Yakhshiev, Ulugbek; Kim, Hyun-Chul
2011-10-01
We present recent studies on the effective mass of the nucleon in infinite and homogeneous nuclear matter and its relation to nuclear matter properties within the framework of the in-medium modified Skyrme model. Medium modifications are achieved by introducing optical potential for pion fields and parametrization of the Skyrme parameter in nuclear medium. The present approach is phenomenologically well justified by pion physics in nuclear matter and describe successfully bulk nuclear matter properties.
International Nuclear Information System (INIS)
Recent advances in variational and perturbative theories are surveyed which offer genuine promise that nuclear matter will soon become a viable tool for investigating nuclear interactions. The basic elements of the hypernetted chain expansion for Jastrow variational functions are briefly reviewed, and comparisons of variational and perturbative results for a series of increasingly complicated systems are presented. Prospects for investigating realistic forces are assessed and the unresolved, open problems are summarized
Chromomagnetism in nuclear matter
Ranjan, Akhilesh; Raina, P. K.
2011-01-01
Quarks are color charged particles. Due to their motion there is a strong possibility of generation of color magnetic field. It is shown that however hadrons are color singlet particles they may have non-zero color magnetic moment. Due to this color magnetic moment hadrons can show color interaction. In this paper we have studied the chromomagnetic properties of nuclear matter.
International Nuclear Information System (INIS)
Instead of discussing finite hypernuclei, we consider the theoretically simpler problem of a hyperon in nuclear matter. Most of the talk is devoted to the much better known case of the ? hyperon. The problem of a ? hyperon in NM is considered at the end. (orig./HSI)
Pseudogap states in nuclear matter
International Nuclear Information System (INIS)
Full text: The protons and neutrons, usually called nucleons, just like electrons in metals may be considered as a degenerate fermi-gas. In this work it was stated that the nuclear matter can be divided into two parts, one corresponding to the high-density nuclear matter and the other one corresponding to the low-density nuclear matter. It was shown that the low- and high-density regions of nuclear matter are similar to the underdoped and overdoped cuprate superconductors
Spin polarized states in nuclear matter with Skyrme effective interaction
Isayev, A A
2004-01-01
The possibility of appearance of spin polarized states in symmetric and strongly asymmetric nuclear matter is analyzed within the framework of a Fermi liquid theory with the Skyrme effective interaction. The zero temperature dependence of the neutron and proton spin polarization parameters as functions of density is found for SkM$^*$, SGII (symmetric case) and SLy4, SLy5 (strongly asymmetric case) effective forces. By comparing free energy densities, it is shown that in symmetric nuclear matter ferromagnetic spin state (parallel orientation of neutron and proton spins) is more preferable than antiferromagnetic one (antiparallel orientation of spins). Strongly asymmetric nuclear matter undergoes at some critical density a phase transition to the state with the oppositely directed spins of neutrons and protons while the state with the same direction of spins does not appear. In comparison with neutron matter, even small admixture of protons strongly decreases the threshold density of spin instability. It is cla...
Upper bounds on asymmetric dark matter self annihilation cross sections
International Nuclear Information System (INIS)
Most models for asymmetric dark matter allow for dark matter self annihilation processes, which can wash out the asymmetry at temperatures near and below the dark matter mass. We study the coupled set of Boltzmann equations for the symmetric and antisymmetric dark matter number densities, and derive conditions applicable to a large class of models for the absence of a significant wash-out of an asymmetry. These constraints are applied to various existing scenarios. In the case of left- or right-handed sneutrinos, very large electroweak gaugino masses, or very small mixing angles are required
Upper Bounds on Asymmetric Dark Matter Self Annihilation Cross Sections
Ellwanger, Ulrich
2012-01-01
Most models for asymmetric dark matter allow for dark matter self annihilation processes, which can wash out the asymmetry at temperatures near and below the dark matter mass. We study the coupled set of Boltzmann equations for the symmetric and antisymmetric dark matter number densities, and derive conditions applicable to a large class of models for the absence of a significant wash-out of an asymmetry. These constraints are applied to various existing scenarios. In the case of left- or right-handed sneutrinos, very large electroweak gaugino masses, or very small mixing angles are required.
Gamma ray constraints on flavor violating asymmetric dark matter
DEFF Research Database (Denmark)
Masina, I.; Panci, P.
2012-01-01
We show how cosmic gamma rays can be used to constrain models of asymmetric Dark Matter decaying into lepton pairs by violating flavor. First of all we require the models to explain the anomalies in the charged cosmic rays measured by PAMELA, Fermi and H.E.S.S.; performing combined fits we determine the allowed values of the Dark Matter mass and lifetime. For these models, we then determine the constraints coming from the measurement of the isotropic gamma-ray background by Fermi for a complete set of lepton flavor violating primary modes and over a range of DM masses from 100 GeV to 10 TeV. We find that the Fermi constraints rule out the flavor violating asymmetric Dark Matter interpretation of the charged cosmic ray anomalies.
Asymmetric dark matter and the Sun
DEFF Research Database (Denmark)
Frandsen, Mads Toudal; Sarkar, Subir
2010-01-01
Cold dark matter particles with an intrinsic matter-antimatter asymmetry do not annihilate after gravitational capture by the Sun and can affect its interior structure. The rate of capture is exponentially enhanced when such particles have self-interactions of the right order to explain structure formation on galactic scales. A `dark baryon' of mass 5 GeV is a natural candidate and has the required relic abundance if its asymmetry is similar to that of ordinary baryons. We show that such particles can solve the `solar composition problem'. The predicted small decrease in the low energy neutrino fluxes may be measurable by the Borexino and SNO+ experiments.
Nucleon properties in nuclear matter
Yakhshiev, Ulugbek; Kim, Hyun-CHul
2011-01-01
We present recent studies on the effective mass of the nucleon in infinite and homogeneous nuclear matter and its relation to nuclear matter properties within the framework of the in-medium modified Skyrme model. Medium modifications are achieved by introducing optical potential for pion fields and parametrization of the Skyrme parameter in nuclear medium. The present approach is phenomenologically well justified by pion physics in nuclear matter and describe successfully bu...
Liquid-gas phase transition and Coulomb instability of asymmetric nuclear systems
International Nuclear Information System (INIS)
We use a chiral SU(3) quark mean field model to study the properties of nuclear systems at finite temperature. The liquid-gas phase transition of symmetric and asymmetric nuclear matter is discussed. For two formulations of the model the critical temperature, Tc, for symmetric nuclear matter is found to be 15.8 MeV and 17.9 MeV. These values are consistent with those derived from recent experiments. The limiting temperatures for finite nuclei are in good agreement with the experimental points
International Nuclear Information System (INIS)
The subject of the doctoral thesis is examination of the properties of kaons in nuclear matter. A specific method is explained that has been developed for the scientific objectives of the thesis and permits description of the kaon-nucleon interactions and kaon-nucleon scattering in a vacuum. The main challenge involved was to find approaches that would enable application of the derived relations out of the kaon mass shell, connected with the second objective, namely to possibly find methods which are independent of models. The way chosen to achieve this goal relied on application of reduction formulas as well as current algebra relations and the PCAC hypothesis. (orig./CB)
Asymmetric dark matter via spontaneous co-genesis
International Nuclear Information System (INIS)
We investigate, in the context of asymmetric dark matter (DM), a new mechanism of spontaneous co-genesis of linked DM and baryon asymmetries, explaining the observed relation between the baryon and DM densities, ?DM?/?B ? 5. The co-genesis mechanism requires a light scalar field, ?, with mass below 5 eV which couples derivatively to DM, much like a 'dark axion'. The field ? can itself provide a final state into which the residual symmetric DM component can annihilate away
Constraining Asymmetric Dark Matter through observations of compact stars
DEFF Research Database (Denmark)
Kouvaris, Christoforos; Tinyakov, Peter
2011-01-01
We put constraints on asymmetric dark matter candidates with spin-dependent interactions based on the simple existence of white dwarfs and neutron stars in globular clusters. For a wide range of the parameters (WIMP mass and WIMP-nucleon cross section), WIMPs can be trapped in progenitors in large numbers and once the original star collapses to a white dwarf or a neutron star, these WIMPs might self-gravitate and eventually collapse forming a mini-black hole that eventually destroys the star. We impose constraints competitive to direct dark matter search experiments, for WIMPs with masses down to the TeV scale.
Asymmetric capture of Dirac dark matter by the Sun
Blennow, Mattias; Clementz, Stefan
2015-08-01
Current problems with the solar model may be alleviated if a significant amount of dark matter from the galactic halo is captured in the Sun. We discuss the capture process in the case where the dark matter is a Dirac fermion and the background halo consists of equal amounts of dark matter and anti-dark matter. By considering the case where dark matter and anti-dark matter have different cross sections on solar nuclei as well as the case where the capture process is considered to be a Poisson process, we find that a significant asymmetry between the captured dark particles and anti-particles is possible even for an annihilation cross section in the range expected for thermal relic dark matter. Since the captured number of particles are competitive with asymmetric dark matter models in a large range of parameter space, one may expect solar physics to be altered by the capture of Dirac dark matter. It is thus possible that solutions to the solar composition problem may be searched for in these type of models.
In-medium nucleons and nucleonic systems: Infinite nuclear matter
Yakhshiev, U. T.
2013-09-01
In the present work we discuss the modifications of infinite nuclear matter properties. The modifications are performed in the framework of the in-medium modified Skyrme model. The model is developed to study the properties of in-medium nucleons and nucleonic systems. The mesonic sector of the model contains the nonlinear pion fields propagating in the nuclear medium. The properties of in-medium pions are defined by the pion-nucleus optical potential. The isospin-breaking part of the optical potential and the isospin-breaking effects in the mesonic sector generate the isospin-breaking effects in the baryonic sector. Further, the isospin-breaking effects in the baryonic sector are related to the asymmetric-matter properties. First, we discuss the binding energy per nucleon and the bulk properties of the isospin-symmetric nuclear matter. Then, we include the isospin-breaking effects and discuss the asymmetric-matter properties.
Covariant density functional theory for nuclear matter
Energy Technology Data Exchange (ETDEWEB)
Badarch, U.
2007-07-01
The present thesis is organized as follows. In Chapter 2 we study the Nucleon-Nucleon (NN) interaction in Dirac-Brueckner (DB) approach. We start by considering the NN interaction in free-space in terms of the Bethe-Salpeter (BS) equation to the meson exchange potential model. Then we present the DB approach for nuclear matter by extending the BS equation for the in-medium NN interaction. From the solution of the three-dimensional in-medium BS equation, we derive the DB self-energies and total binding energy which are the main results of the DB approach, which we later incorporate in the field theoretical calculation of the nuclear equation of state. In Chapter 3, we introduce the basic concepts of density functional theory in the context of Quantum Hadrodynamics (QHD-I). We reach the main point of this work in Chapter 4 where we introduce the DDRH approach. In the DDRH theory, the medium dependence of the meson-nucleon vertices is expressed as functionals of the baryon field operators. Because of the complexities of the operator-valued functionals we decide to use the mean-field approximation. In Chapter 5, we contrast microscopic and phenomenological approaches to extracting density dependent meson-baryon vertices. Chapter 6 gives the results of our studies of the EOS of infinite nuclear matter in detail. Using formulas derived in Chapters 4 and 5 we calculate the properties of symmetric and asymmetric nuclear matter and pure neutron matter. (orig.)
Propagation of neutrinos in nuclear matter
International Nuclear Information System (INIS)
We study the elementary interactions between neutrinos and dense matter in a proto-neutron star. Equations of state obtained with different nuclear effective interactions (Skyrme, Gogny, Relativistic Lagrangians) are first discussed. Then, we characterize their stability in spin and isospin. We derive magnetic susceptibilities for all isospin asymmetry values as a function of Landau parameters G??'0 (where ?, ?' = proton or neutron). From this work, we select a parametrization for each of the 3 effective forces: Sly230b,D1P,NL3. We calculate the pure neutron matter and asymmetric nuclear matter response functions with and without charge exchange, describing nuclear correlations in both approaches: non-relativistic (Hartree-Fock with Skyrme forces, then complete RPA) and relativistic (in the Hartree approximation). At the end, we calculate neutrino mean free paths neutral current and charged current reactions. Comparisons between relativistic and non-relativistic approaches allow us to identify relativistic effects in nuclear matter at densities as low as twice the saturation density. RPA correlations make the medium more transparent to neutrinos compared to free Fermi gas. The importance of the effective mass in mean free path calculations is also shown. (author)
Covariant density functional theory for nuclear matter
International Nuclear Information System (INIS)
The present thesis is organized as follows. In Chapter 2 we study the Nucleon-Nucleon (NN) interaction in Dirac-Brueckner (DB) approach. We start by considering the NN interaction in free-space in terms of the Bethe-Salpeter (BS) equation to the meson exchange potential model. Then we present the DB approach for nuclear matter by extending the BS equation for the in-medium NN interaction. From the solution of the three-dimensional in-medium BS equation, we derive the DB self-energies and total binding energy which are the main results of the DB approach, which we later incorporate in the field theoretical calculation of the nuclear equation of state. In Chapter 3, we introduce the basic concepts of density functional theory in the context of Quantum Hadrodynamics (QHD-I). We reach the main point of this work in Chapter 4 where we introduce the DDRH approach. In the DDRH theory, the medium dependence of the meson-nucleon vertices is expressed as functionals of the baryon field operators. Because of the complexities of the operator-valued functionals we decide to use the mean-field approximation. In Chapter 5, we contrast microscopic and phenomenological approaches to extracting density dependent meson-baryon vertices. Chapter 6 gives the results of our studies of the EOS of infinite nuclear matter in detail. Using formulas derived in Chapters 4 and 5 we calculate the properties of symmetric and asymmetric nuclear matter and pure neutron matter. (orig.)
Nuclear matter and electron scattering
Energy Technology Data Exchange (ETDEWEB)
Sick, I. [Dept. fuer Physik und Astronomie, Univ. Basel (Switzerland)
1998-06-01
We show that inclusive electron scattering at large momentum transfer allows a measurement of short-range properties of nuclear matter. This provides a very valuable constraint in selecting the calculations appropriate for predicting nuclear matter properties at the densities of astrophysical interest. (orig.)
Multi skyrmions in nuclear matter
Yakhshiev, U T
2002-01-01
Properties of multi skyrmions in a nuclear matter are analyzed. The deformation effect is taken into account via distortion of the profile function of the chiral field under action of an external field. Masses of classical multi skyrmions in a nuclear matter are discussed. (author)
Asymmetric Dark Matter from a GeV Hidden Sector
Cohen, Timothy; Pierce, Aaron; Zurek, Kathryn M
2010-01-01
Asymmetric Dark Matter (ADM) models relate the dark matter density to the baryon asymmetry, so that a natural mass scale for ADM is around a few GeV. In existing models of ADM, this mass scale is unexplained; here we generate this GeV scale for dark matter (DM) from the weak scale via gauge kinetic mixing with a new Abelian dark force. In addition, this dark sector provides an efficient mechanism for suppressing the symmetric abundance of DM through annihilations to the dark photon. We augment this sector with a higher dimensional operator responsible for communicating the baryon asymmetry to the dark sector. Our framework also provides DM candidate for gauge mediation models. It results in a direct detection cross section of interest for current experiments: sigma less than or similar to 10^{-42} cm^2 for DM masses in the range 1 - 15 GeV.
A Model of Asymmetric Hadronic Dark Matter and Leptogenesis
Yang, Wei-Min
2015-01-01
The paper suggests a model to account for the common origins of the asymmetric dark matter (ADM) and matter-antimatter asymmetry. The ADM nature is a stable hadronic particle consisting of a heavy color scalar and a light $u$ quark, which is formed after the QCD phase transition. At the early stage the ADM are in thermal equilibrium through collisions with the nucleons, moreover, they can emit the $\\gamma$ photons with $0.32$ MeV energy. However they are decoupling and become the dark matter at the temperature about $130$ MeV. The mass upper limit of the ADM is predicted as $M_{D}<1207$ GeV. It is feasible and promising to test the model in future experiments.
Pion correlations in Nuclear Matter
P. K. Panda; Sarangi, S.; da Providência, J.
2009-01-01
The saturation properties of the nuclear matter taking pion correlations into account is studied. We construct a Bogoliubov transformations for the pion pair operators and calculate the energy associated with the pion pairs. The pion dispersion relation is investigated. We next study the correlation energy due to one pion exchange in nuclear matter and neutron matter at random phase approximation using the generator coordinate method. The techniques of the charged pion corre...
What can we learn from nuclear matter instabilities
International Nuclear Information System (INIS)
We discuss the features of instabilities in binary systems, in particular for asymmetric nuclear matter. We show the relevance for the interpretation of results obtained in experiments and in 'ab initio' simulations of the reaction 124 Sn + nat Sn at 50 MeV/n (authors)
What can we learn from Nuclear Matter Instabilities?
Baran, V.; M. Colonna; Di Toro, M; Zielinska-Pfabe, M.; Wolter, H. H.
2000-01-01
We discuss the features of instabilities in binary systems, in particular, for asymmetric nuclear matter. We show its relevance for the interpretation of results obtained in experiments and in "ab initio" simulations of the reaction between $^{124}Sn+^{124}Sn$ at 50AMeV.}
Chiral thermodynamics of nuclear matter
Energy Technology Data Exchange (ETDEWEB)
Fiorilla, Salvatore
2012-10-23
The equation of state of nuclear matter is calculated at finite temperature in the framework of in-medium chiral perturbation theory up to three-loop order. The dependence of its thermodynamic properties on the isospin-asymmetry is investigated. The chiral quark condensate is evaluated for symmetric nuclear matter. Its behaviour as a function of density and temperature sets important nuclear physics constraints for the QCD phase diagram.
Chiral thermodynamics of nuclear matter
International Nuclear Information System (INIS)
The equation of state of nuclear matter is calculated at finite temperature in the framework of in-medium chiral perturbation theory up to three-loop order. The dependence of its thermodynamic properties on the isospin-asymmetry is investigated. The chiral quark condensate is evaluated for symmetric nuclear matter. Its behaviour as a function of density and temperature sets important nuclear physics constraints for the QCD phase diagram.
Bulk matters on symmetric and asymmetric de Sitter thick branes
International Nuclear Information System (INIS)
An asymmetric thick domain wall solution with de Sitter (dS) expansion in five dimensions can be constructed from a symmetric one by using a same scalar (kink) with different potentials. In this paper, by presenting the mass-independent potentials of Kaluza-Klein (KK) modes in the corresponding Schrödinger equations, we investigate the localization and mass spectra of various bulk matter fields on the symmetric and asymmetric dS thick branes. For spin 0 scalars and spin 1 vectors, the potentials of KK modes in the corresponding Schrödinger equations are the modified Pöschl-Teller potentials, and there exist a mass gap and a series of continuous spectrum. It is shown that the spectrum of scalar KK modes on the symmetric dS brane contains only one bound mode (the massless mode). However, for the asymmetric dS brane with a large asymmetric factor, there are two bound scalar KK modes: a zero mode and a massive mode. For spin 1 vectors, the spectra of KK modes on both dS branes consist of a bound massless mode and a set of continuous ones, i.e., the asymmetric factor does not change the number of the bound vector KK modes. For spin 1/2 fermions, two types of kink-fermion couplings are investigated in detail. For the usual Yukawa coupling ?barPsi??, there exists no mass gap but a continuous gapless spectrum of KK states. For the scalar-fermion coupling ?barPsisin(?/?0)cos??(?/?0)? with a positive coupling constant ?, there exist some discrete bound KK modes and a series of continuous ones. The total number of bound states increases with the coupling constant ?. For the case of the symmetric dS brane and positive ?, there are NL(NL ? 1) left chiral fermion bound states (including zero mode and massive KK modes) and NL?1 right chiral fermion bound states (including only massive KK modes). For the asymmetric dS brane scenario, the asymmetric factor a reduces the number of the bound fermion KK modes. For large enough a, there would not be any right chiral fermion bound mode, but at least one left chiral fermion zero mode
Condensed Matter Nuclear Science
Biberian, Jean-Paul
2006-02-01
1. General. A tribute to gene Mallove - the "Genie" reactor / K. Wallace and R. Stringham. An update of LENR for ICCF-11 (short course, 10/31/04) / E. Storms. New physical effects in metal deuterides / P. L. Hagelstein ... [et al.]. Reproducibility, controllability, and optimization of LENR experiments / D. J. Nagel -- 2. Experiments. Electrochemistry. Evidence of electromagnetic radiation from Ni-H systems / S. Focardi ... [et al.]. Superwave reality / I. Dardik. Excess heat in electrolysis experiments at energetics technologies / I. Dardik ... [et al.]. "Excess heat" during electrolysis in platinum/K[symbol]CO[symbol]/nickel light water system / J. Tian ... [et al.]. Innovative procedure for the, in situ, measurement of the resistive thermal coefficient of H(D)/Pd during electrolysis; cross-comparison of new elements detected in the Th-Hg-Pd-D(H) electrolytic cells / F. Celani ... [et al.]. Emergence of a high-temperature superconductivity in hydrogen cycled Pd compounds as an evidence for superstoihiometric H/D sites / A. Lipson ... [et al.]. Plasma electrolysis. Calorimetry of energy-efficient glow discharge - apparatus design and calibration / T. B. Benson and T. O. Passell. Generation of heat and products during plasma electrolysis / T. Mizuno ... [et al.]. Glow discharge. Excess heat production in Pd/D during periodic pulse discharge current in various conditions / A. B. Karabut. Beam experiments. Accelerator experiments and theoretical models for the electron screening effect in metallic environments / A. Huke, K. Czerski, and P. Heide. Evidence for a target-material dependence of the neutron-proton branching ratio in d+d reactions for deuteron energies below 20keV / A. Huke ... [et al.]. Experiments on condensed matter nuclear events in Kobe University / T. Minari ... [et al.]. Electron screening constraints for the cold fusion / K. Czerski, P. Heide, and A. Huke. Cavitation. Low mass 1.6 MHz sonofusion reactor / R. Stringham. Particle detection. Research into characteristics of X-ray emission laser beams from solidstate cathode medium of high-current glow discharge / A. B. Karabut. Charged particles from Ti and Pd foils / L. Kowalski ... [et al.]. Cr-39 track detectors in cold fusion experiments: review and perspectives / A. S. Roussetski. Energetic particle shower in the vapor from electrolysis / R. A. Oriani and J. C. Fisher. Nuclear reactions produced in an operating electrolysis cell / R. A. Oriani and J. C. Fisher. Evidence of microscopic ball lightning in cold fusion experiments / E. H. Lewis. Neutron emission from D[symbol] gas in magnetic fields under low temperature / T. Mizuno ... [et al.]. Energetic charged particle emission from hydrogen-loaded Pd and Ti cathodes and its enhancement by He-4 implantation / A. G. Lipson ... [et al.]. H-D permeation. Observation of nuclear transmutation reactions induced by D[symbol] gas permeation through Pd complexes / Y. Iwamura ... [et al.]. Deuterium (hydrogen) flux permeating through palladium and condensed matter nuclear science / Q. M. Wei ... [et al.]. Triggering. Precursors and the fusion reactions in polarized Pd/D-D[symbol]O system: effect of an external electric field / S. Szpak, P. A. Mosier-Boss, and F. E. Gordon. Calorimetric and neutron diagnostics of liquids during laser irradiation / Yu. N. Bazhutov ... [et al.]. Anomalous neutron capture and plastic deformation of Cu and Pd cathodes during electrolysis in a weak thermalized neutron field: evidence of nuclei-lattice exchange / A. G. Lipson and G. H. Miley. H-D loading. An overview of experimental studies on H/Pd over-loading with thin Pd wires and different electrolytic solutions / A. Spallone ... [et al.] -- 3. Transmutations. Photon and particle emission, heat production, and surface transformation in Ni-H system / E. Campari ... [et al.]. Surface analysis of hydrogen-loaded nickel alloys / E. Campari ... [et al.]. Low-energy nuclear reactions and the leptonic monopole / G. Lochak and L. Urutskoev. Results of analysis of Ti foil after glow discharge with deuterium / I. B. Savvat
Takeshita, Hisako; Sawa, Hitoshi
2005-01-01
?-Catenin can promote adhesion at the cell cortex and mediate Wnt signaling in the nucleus. We show that, in Caenorhabditis elegans, both WRM-1/?-catenin and LIT-1 kinase localize to the anterior cell cortex during asymmetric cell division but to the nucleus of the posterior daughter afterward. Both the cortical and nuclear localizations are regulated by Wnts and are apparently coupled. We also found that the daughters show different nuclear export rates for LIT-1. Our results indicate that W...
Nuclear matter and nuclear hamiltonian
International Nuclear Information System (INIS)
In this talk I suggest that it may be possible to explain the low energy nuclear properties with a three-body hamiltonian. The need for the three nucleon interaction (TNI) in the nuclear hamiltonian is exhibited. The TNI has been studied with the meson theory in some details, however we use a simple pedagogical model of Vsub(i)sub(j)sub(k) in our many-body calculations. (orig./HSI)
Exposing asymmetric gray matter vulnerability in amyotrophic lateral sclerosis
Directory of Open Access Journals (Sweden)
Matthew S. Devine
2015-01-01
Full Text Available Limb weakness in amyotrophic lateral sclerosis (ALS is typically asymmetric. Previous studies have identified an effect of limb dominance on onset and spread of weakness, however relative atrophy of dominant and non-dominant brain regions has not been investigated. Our objective was to use voxel-based morphometry (VBM to explore gray matter (GM asymmetry in ALS, in the context of limb dominance. 30 ALS subjects were matched with 17 healthy controls. All subjects were right-handed. Each underwent a structural MRI sequence, from which GM segmentations were generated. Patterns of GM atrophy were assessed in ALS subjects with first weakness in a right-sided limb (n = 15 or left-sided limb (n = 15. Within each group, a voxelwise comparison was also performed between native and mirror GM images, to identify regions of hemispheric GM asymmetry. Subjects with ALS showed disproportionate atrophy of the dominant (left motor cortex hand area, irrespective of the side of first limb weakness (p < 0.01. Asymmetric atrophy of the left somatosensory cortex and temporal gyri was only observed in ALS subjects with right-sided onset of limb weakness. Our VBM protocol, contrasting native and mirror images, was able to more sensitively detect asymmetric GM pathology in a small cohort, compared with standard methods. These findings indicate particular vulnerability of dominant upper limb representation in ALS, supporting previous clinical studies, and with implications for cortical organisation and selective vulnerability.
Charmonium mass in nuclear matter
Ko, C. M.; Lee, Su Houng
2002-01-01
The mass shift of charmonium states in nuclear matter is studied in the perturbative QCD approach. The leading-order effect due to the change of gluon condensate in nuclear matter is evaluated using the leading-order QCD formula, while the higher-twist effect due to the partial restoration of chiral symmetry is estimated using a hadronic model. We find that while the mass of $J/\\psi$ in nuclear matter decreases only slightly, those of $\\psi(3686)$ and $\\psi(3770)$ states are...
Asymmetric dark matter from a GeV hidden sector
International Nuclear Information System (INIS)
Asymmetric dark matter (ADM) models relate the dark matter (DM) density to the baryon asymmetry, so that a natural mass scale for ADM is around a few GeV. In existing models of ADM, this mass scale is unexplained; here we generate this GeV scale for DM) from the weak scale via gauge kinetic mixing with a new Abelian dark force. In addition, this dark sector provides an efficient mechanism for suppressing the symmetric abundance of DM through annihilations to the dark photon. We augment this sector with a higher dimensional operator responsible for communicating the baryon asymmetry to the dark sector. Our framework also provides a DM candidate for gauge mediation models. It results in a direct detection cross section of interest for current experiments: ?p -41 cm2 for DM masses in the range 1-15 GeV.
Matter & More in Nuclear Collisions
Satz, H.
2001-01-01
The aim of high energy nuclear collisions is to study the transition from hadronic matter to a plasma of deconfined quarks and gluons. I review the basic questions of this search and summarize recent theoretical developments in the field.
A Dirac description of ¹S0+³ S1-³ D1 pairing in nuclear matter
Scientific Electronic Library Online (English)
B. Funke, Haas; B. V., Carlson; Tobias, Frederico.
2004-09-01
Full Text Available We develop a Dirac-Hartree-Fock-Bogoliubov description of nuclear matter pairing in ¹S0 and ³S¹-³ D¹ channels. Here we investigate the density dependence ot the ¹S0 and ³S¹-³ D¹ pairing fields in asymmetric nuclear matter, using a Bonn meson-exchange interaction between Dirac nucleons. In this work, [...] we present preliminary results.
Bosonic variables in nuclear matters
International Nuclear Information System (INIS)
It is shown that the boson theoretical interpretation of nuclear forces nessecitates the introduction of bosonic variables within the state function of nuclear matter. In this framework the 2-boson exchange plays a decisive role and calls for the introduction of special selfenergy diagrams. This generalized scheme is discussed with the help of a solvable field theoretical model. (orig.)
The ab-initio approach to nuclear matter and its extreme states
International Nuclear Information System (INIS)
In this talk, I will review several issues related to the nuclear matter equation of state, with particular emphasis on isospin-asymmetric matter. I will stress the importance of pursuing a microscopic approach towards a better understanding of dense and exotic matter. (author)
Reflection-asymmetric nuclear deformations within the Density Functional Theory
Olsen, E; Nazarewicz, W; Stoitsov, M; 10.1088/1742-6596/402/1/012034
2013-01-01
Within the nuclear density functional theory (DFT) we study the effect of reflection-asymmetric shapes on ground-state binding energies and binding energy differences. To this end, we developed the new DFT solver AxialHFB that uses an approximate second-order gradient to solve the Hartree-Fock-Bogoliubov equations of superconducting DFT with the quasi-local Skyrme energy density functionals. Illustrative calculations are carried out for even-even isotopes of radium and thorium.
Induced interaction stabilizing nuclear matter
International Nuclear Information System (INIS)
Excitation modes of nuclear matter at various densities are investigated including the effects of ? excitations. Collective features are observed at small densities in the scalar-isoscalar channel and at large densities for the longitudinal isovector mode. Using the Brueckner G-matrix for the residual interaction, the RPA approximation predicts an instability of nuclear matter against these modes. The renormalization of the residual interaction by the so called induced interaction yields a stabilization of the collective modes. The effects of the corresponding phonon exchange terms on the particle-hole interaction and on the effective mass are discussed. 8 refs.; 4 figs
Light Nuclei within Nuclear Matter
Beyer, M; Furutachi, N; Oryu, S
2005-01-01
We investigate the properties of 3He, 4He, 6He, 7Li and 16O nuclei in nuclear matter of finite temperature and density. A Dyson expansion of the many-body Green function leads to few-body equations that are solved using the ntegro-Differential Equation Approach (IDEA) and the Antisymmetrized Molecular Dynamics (AMD) methods. The use of the latter method allows us to trace the individual movement of the wave packet for each nucleon and the formation and disintegration of quasi-nuclei in a changing thermodynamical nuclear matter environment.
International Nuclear Information System (INIS)
The goal in this thesis is thus twofold: The first is to investigate the feasibility of using heavy ion collisions to create conditions in the laboratory which are ripe for the formation of a quark-gluon plasma. The second is to develop a technique for studying some of the many non-perturbative features of this novel phase of matter
Indirect detection signatures for the origin of asymmetric dark matter
Zhao, Yue; Zurek, Kathryn M.
2014-07-01
We study the decay signatures of Asymmetric Dark Matter (ADM) via higher dimension operators which are responsible for generating the primordial dark matter (DM) asymmetry. Since the signatures are sensitive both to the nature of the higher dimension operator generating the DM asymmetry and to the sign of the baryon or lepton number that the DM carries, indirect detection may provide a window into the nature of the mechanism which generates the DM asymmetry. We consider in particular dimension-6 fermionic operators of the form ADM = X B-L /M 2, where B-L = u c d c d c , ??e c , q?d c (or operators related through a Hermitian conjugate) with the scale M around or just below the GUT scale. We derive constraints on ADM particles both in the natural mass range (around a few GeV), as well as in the range between 100 GeV to 10 TeV. For light ADM, we focus on constraints from both the low energy gamma ray data and proton/antiproton fluxes. For heavy ADM, we consider ?-rays and proton/anti-proton fluxes, and we fit e + /e - data from AMS-02 and H.E.S.S. (neglecting the Fermi charged particle fluxes which disagree with AMS-02 below 100 GeV). We show that, although the best fit regions from electron/positron measurement are still in tension with other channels on account of the H.E.S.S. measurement at high energies, compared to an ordinary symmetric dark matter scenario, the decay of DM with a primordial asymmetry reduces the tension. Better measurement of the flux at high energy will be necessary to draw a definite conclusion about the viability of decaying DM as source for the signals.
Electron scattering from nuclear matter
International Nuclear Information System (INIS)
We use inclusive electron scattering to study the short-range aspects of nuclear matter wave functions. Comparison to data at large momentum transfer allows detailed studies of P(k, E) at large momenta, N-N correlations and colour transparency. (orig.)
Nuclear and neutron matters at low density
Gad, Kh.
2015-08-01
In this study, symmetric and asymmetric nuclear matter, as well as pure neutron matter in the low-density regime, where the density ranges 0.01 fm-3 ? 0.13 fm-3, have been investigated. Two different realistic and accurate two-body forces are considered. These include Argonne V18 and the CD-Bonn, which give quite different equations of state. The binding energy per nucleon as a function of the density is calculated using the Brueckner-Hartree-Fock approximation. Both the conventional (gap) and continuous choice of single-particle energies are utilized. For the sake of comparison, the equation of state within the self-consistent Green's function approach is calculated using the CD-Bonn potential. The contribution of the hole-hole terms leads to a repulsive contribution to the energy per nucleon which increases with the nuclear density. Significantly, very good agreement between the experimental symmetry energy values and those calculated in the self-consistent Green's function and BHF approaches especially at low density, has been accomplished. Finally, The results are compared with those from various many-body approaches, such as variational and relativistic mean field approaches.
Energy Technology Data Exchange (ETDEWEB)
Heiselberg, H. [NORDITA, Copenhagen (Denmark)
1998-06-01
The kaon energy in a nuclear medium and its dependence on kaon-nucleon and nucleon-nucleon correlations is discussed. The transition from the Lenz potential at low densities to the Hartree potential at high densities can be calculated analytically by making a Wigner-Seitz cell approximation and employing a square well potential. As the Hartree potential is less attractive than the Lenz one, kaon condensation inside cores of neutron stars appears to be less likely than previously estimated. (orig.)
Big Bang synthesis of nuclear dark matter
Hardy, Edward; Lasenby, Robert; March-Russell, John; West, Stephen M.
2015-06-01
We investigate the physics of dark matter models featuring composite bound states carrying a large conserved dark "nucleon" number. The properties of sufficiently large dark nuclei may obey simple scaling laws, and we find that this scaling can determine the number distribution of nuclei resulting from Big Bang Dark Nucleosynthesis. For plausible models of asymmetric dark matter, dark nuclei of large nucleon number, e.g. ? 108, may be synthesised, with the number distribution taking one of two characteristic forms. If small-nucleon-number fusions are sufficiently fast, the distribution of dark nuclei takes on a logarithmically-peaked, universal form, independent of many details of the initial conditions and small-number interactions. In the case of a substantial bottleneck to nucleosynthesis for small dark nuclei, we find the surprising result that even larger nuclei, with size ? 108, are often finally synthesised, again with a simple number distribution. We briefly discuss the constraints arising from the novel dark sector energetics, and the extended set of (often parametrically light) dark sector states that can occur in complete models of nuclear dark matter. The physics of the coherent enhancement of direct detection signals, the nature of the accompanying dark-sector form factors, and the possible modifications to astrophysical processes are discussed in detail in a companion paper.
Nuclear fluxes during coherent tunnelling in asymmetric double well potentials
Liu, ChunMei; Manz, Jörn; Yang, Yonggang
2015-08-01
Previous results for nuclear fluxes during coherent tunnelling of molecules with symmetric double well potentials are extended to fluxes in asymmetric double well potentials. The theory is derived using the two-state approximation (TSA). The symmetric system serves as a reference. As an example, we consider the one-dimensional model of the tunnelling inversion of oriented ammonia, with semiclassical dipole coupling to an electric field. The tunnelling splitting increases with the dipole coupling by a factor f?slant 1. The tunnelling time decreases by 1/f. The nuclear density appears as the sum of two parts: The tunnelling part decreases as {1/f}2 times the density of the symmetric reference, whereas the non-tunnelling part is the initial density times ?ft({{1-1}/f}2\\right). Likewise, the nuclear flux decreases by 1/f, with essentially the same shape as for the symmetric reference, with maximum value at the potential barrier. Coherent nuclear tunnellings starting from the upper or lower wells of the asymmetric potential are equivalent. The results are universal, in the frame of the TSA, hence they allow straightforward extrapolations from one system to others. This is demonstrated by the prediction of isotope effects for five isotopomers of ammonia.
More on nucleon-nucleon cross sections in symmetric and asymmetric matter
Sammarruca, F; Krastev, P.
2005-01-01
Following a recent work, we present numerical results for total two-nucleon effective cross sections in isospin symmetric and asymmetric matter. The present calculations include the additional effect of Pauli blocking of the final states.
Role of isospin in nuclear-matter liquid-gas phase transition
International Nuclear Information System (INIS)
Nuclear matter presents a phase transition of the liquid-gas type. This well-known feature is due to the nuclear interaction profile (mean-range attractive, short-range repulsive). Symmetric-nuclear-matter thermodynamics is thus analogous to that of a Van der Waals fluid. The study shows up to be more complex in the case of asymmetric matter, composed of neutrons and protons in an arbitrary proportion. Isospin, which distinguishes both constituents, gives a measure of this proportion. Studying asymmetric matter, isospin is an additional degree of freedom, which means one more dimension to consider in the space of observables. The nuclear liquid-gas transition is associated with the multi-fragmentation phenomenon observed in heavy-ion collisions, and to compact-star physics: the involved systems are neutron rich, so they are affected by the isospin degree of freedom. The present work is a theoretical study of isospin effects which appear in the asymmetric nuclear matter liquid-gas phase transition. A mean-field approach is used, with a Skyrme nuclear effective interaction. We demonstrate the presence of a first-order phase transition for asymmetric matter, and study the isospin distillation phenomenon associated with this transition. The case of phase separation at thermodynamic equilibrium is compared to spinodal decomposition. Finite size effects are addressed, as well as the influence of the electron gas which is present in the astrophysical context. (author)
Weak Response of Nuclear Matter
Farina, Nicola
2009-01-01
The quantitative understanding of neutrino interactions with nuclei and nuclear matter is needed to the study of many different problems. In the astrophysics environment, neutrino-nucleon and neutrino-nucleus reaction rates are used as inputs in the simulations of phenomena like supernov$\\ae$ explosions and neutron star cooling. In the field of neutrino physics, the quantitative knowledge of neutrino-nucleus cross-section is critical to reduce the systematic uncertainty of t...
Quartic isospin asymmetry energy of nuclear matter from chiral pion-nucleon dynamics
Kaiser, N.
2015-06-01
Based on a chiral approach to nuclear matter, the quartic term in the expansion of the equation of state of isospin-asymmetric nuclear matter is calculated. The contributions to the quartic isospin asymmetry energy A4(kf) arising from 1 ? exchange and chiral 2 ? exchange in nuclear matter are calculated analytically together with three-body terms involving virtual ? (1232 ) isobars. From these interaction terms one obtains at saturation density ?0=0.16 fm-3 the value A4(kf 0) =1.5 MeV , more than three times as large as the kinetic energy part. Moreover, iterated 1 ? exchange exhibits components for which the fourth derivative with the respect to the isospin asymmetry parameter ? becomes singular at ? =0 . The genuine presence of a nonanalytical term ?4ln|? | in the expansion of the energy per particle of isospin-asymmetric nuclear matter is demonstrated by evaluating an s -wave contact interaction at second order.
Quasiparticle interaction in nuclear matter
International Nuclear Information System (INIS)
A microscopic calculation of the quasiparticle interaction in nuclear matter is detailed. In order to take especial care of the contributions from the low momentum states, a model space is introduced. Excluded from the model space, the high momentum states are absorbed into the model interaction. Brueckner theory suggests the choice of a truncated G-matrix as a good approximation for this model interaction. A simple perturbative approach is attempted within the model space. The calculated quasiparticle interaction is consistent with experimental results. (11 tables, 14 figures)
Asymmetric Dark Matter and CP Violating Scatterings in a UV Complete Model
Baldes, Iason; Bell, Nicole F.(ARC Centre of Excellence for Particle Physics at the Terascale, School of Physics, The University of Melbourne, Victoria 3010, Australia); Millar, Alexander J.; Volkas, Raymond R
2015-01-01
We explore possible asymmetric dark matter models using CP violating scatterings to generate an asymmetry. In particular, we introduce a new model, based on DM fields coupling to the SM Higgs and lepton doublets, $\\overline{L}H$, and explore its UV completions. We study the CP violation and asymmetry formation of this model, to demonstrate that it is capable of producing the correct abundance of dark matter and the observed matter-antimatter asymmetry. Crucial to achieving t...
Phase transition from nuclear matter to color superconducting quark matter
Bentz, W; Ishii, N; Thomas, A W
2003-01-01
We construct the nuclear and quark matter equations of state at zero temperature in an effective quark theory (the Nambu-Jona-Lasinio model), and discuss the phase transition between them. The nuclear matter equation of state is based on the quark-diquark description of the single nucleon, while the quark matter equation of state includes the effects of scalar diquark condensation (color superconductivity). The effect of diquark condensation on the phase transition is discussed in detail.
Asymmetric dark matter annihilation as a test of non-standard cosmologies
International Nuclear Information System (INIS)
We show that the relic abundance of the minority component of asymmetric dark matter can be very sensitive to the expansion rate of the Universe and the temperature of transition between a non-standard pre-Big Bang Nucleosynthesis cosmological phase and the standard radiation dominated phase, if chemical decoupling happens before this transition. In particular, because the annihilation cross section of asymmetric dark matter is typically larger than that of symmetric dark matter in the standard cosmology, the decrease in relic density of the minority component in non-standard cosmologies with respect to the majority component may be compensated by the increase in annihilation cross section, so that the annihilation rate at present of asymmetric dark matter, contrary to general belief, could be larger than that of symmetric dark matter in the standard cosmology. Thus, if the annihilation cross section of the asymmetric dark matter candidate is known, the annihilation rate at present, if detectable, could be used to test the Universe before Big Bang Nucleosynthesis, an epoch from which we do not yet have any data
Calderon de La Barca Sanchez, Manuel
2010-11-01
Over the past decade, the experiments at the Relativistic Heavy Ion Collider have produced tantalizing evidence for a new state of nuclear matter. The study of this phase presents to us the opportunity to study the strong force at high temperature. Much as the field of condensed matter has benefited through the study of collective phenomena based on Quantum Electro-Dynamics (QED), we are at the beginning of our study of the unique properties that matter possesses when interacting through Quantum Chromo-Dynamics (QCD). The quark-gluon plasma that has been observed in the collisions at RHIC showcases some intriguing properties. The bulk of the matter produced during the highest temperature phase exhibits near perfect liquid behavior. At the same time, the plasma is extremely opaque to the passage of high energy color-charged partons, a phenomenon christened ``jet quenching.'' The density is large enough that even the massive quarks, charm and beauty, show evidence for a surprising amount of quenching. These findings attest to the success of the RHIC program in the past decade. As we look forward to another decade, we aim to study these exciting phenomena with increased precision in order to make quantitative assessments of the medium properties. In order to achieve this, a ten-fold increase to the RHIC collider luminosity, targeted detector upgrades, and advances in theory are envisioned. In this talk, we present an overview of current results, the key questions that we aim to address in the next decade, and how the planned new capabilities of accelerators and detectors can help us to answer them.
Deuteron formation in nuclear matter
International Nuclear Information System (INIS)
We investigate deuteron formation in nuclear matter at finite temperatures within a systematic quantum statistical approach. We consider formation through three-body collisions relevant already at rather moderate densities because of the strong correlations. The three-body in-medium reaction rates driven by the break-up cross section are calculated using exact three-body equations (Alt-Grassberger-Sandhas type) that have been suitably modified to consistently include the energy shift and the Pauli blocking. Important quantities are the lifetime of deuteron fluctuations and the chemical relaxation time. We find that the respective times differ substantially while using in-medium or isolated cross sections. We expect implications for the description of heavy ion collisions in particular for the formation of light charged particles at low to intermediate energies
Deuteron formation in nuclear matter
Kuhrts, C; Röpke, G
2000-01-01
We investigate deuteron formation in nuclear matter at finite temperatures within a systematic quantum statistical approach. We consider formation through three-body collisions relevant already at rather moderate densities because of the strong correlations. The three-body in-medium reaction rates driven by the break-up cross section are calculated using exact three-body equations (Alt-Grassberger-Sandhas type) that have been suitably modified to consistently include the energy shift and the Pauli blocking. Important quantities are the lifetime of deuteron fluctuations and the chemical relaxation time. We find that the respective times differ substantially while using in-medium or isolated cross sections. We expect implications for the description of heavy ion collisions in particular for the formation of light charged particles at low to intermediate energies.
Hyperons in nuclear matter from SU(3) chiral effective field theory
Petschauer, S; Kaiser, N; Meißner, Ulf-G; Weise, W
2015-01-01
Brueckner theory is used to investigate the properties of hyperons in nuclear matter. The hyperon-nucleon interaction is taken from chiral effective field theory at next-to-leading order with SU(3) symmetric low-energy constants. Furthermore, the underlying nucleon-nucleon interaction is also derived within chiral effective field theory. We present the single-particle potentials of Lambda and Sigma hyperons in symmetric and asymmetric nuclear matter computed with the continuous choice for intermediate spectra. The results are in good agreement with the empirical information. In particular, our calculation gives a repulsive Sigma-nuclear potential and a weak Lambda-nuclear spin-orbit force.
Asymmetric sneutrino dark matter and the ?b/?DM puzzle
International Nuclear Information System (INIS)
The inferred values of the cosmological baryon and dark matter densities are strikingly similar, but in most theories of the early universe there is no true explanation of this fact; in particular, the baryon asymmetry and thus density depends upon unknown, and a priori unknown and possibly small, CP-violating phases which are independent of all parameters determining the dark matter density. We consider models of dark matter possessing a particle-antiparticle asymmetry where this asymmetry determines both the baryon asymmetry and strongly effects the dark matter density, thus naturally linking ?b and ?dm. We show that sneutrinos can play the role of such dark matter in a previously studied variant of the MSSM in which the light neutrino masses result from higher-dimensional supersymmetry-breaking terms
Bordbar, G H; Taghizade, M
2015-01-01
In this work, we have done a completely microscopic calculation using a many-body variational method based on the cluster expansion of energy to compute the asymmetry energy of nuclear matter. In our calculations, we have employed the $AV_{18}$ nuclear potential. We have also investigated the temperature and density dependence of asymmetry energy. Our results show that the asymmetry energy of nuclear matter depends on both density and temperature. We have also studied the effects of different terms in the asymmetry energy of nuclear matter. These investigations indicate that at different densities and temperatures, the contribution of parabolic term is very substantial with respect to the other terms. Therefore, we can conclude that the parabolic approximation is a relatively good estimation, and our calculated binding energy of asymmetric nuclear matter is in a relatively good agreement with that of semi-empirical mass formula. However, for the accurate calculations, it is better to consider the effects of o...
Nuclear matter may enhance chiral symmetry breaking
International Nuclear Information System (INIS)
We study chiral symmetry breaking in nuclear matter. For the dynamics we use a class of quark models with a chiral invariant confining potential. The mass gap equation is obtained when we minimize the energy of the matter with respect to the chiral angle cphi and to the quark wave function in the nucleon. At low nuclear density ?, we find that the chiral angle decreases slightly, the nucleon swells and the nucleon mass decreases. However, for the density of nuclear matter, we find that the chiral angle suffers an enhancement. We briefly discuss the physical consequences of this effect and its independence of the microscopic quark model
Interaction of nuclear radiation with matter
International Nuclear Information System (INIS)
This chapter of a textbook presents an overview of an important aspect of nuclear physics and nuclear chemistry. The effects of the interaction of nuclear radiation with substances are classified according to the acting particle, and the reacting constituents of the substance. The interactions of alpha radiation with matter (slowing down, scattering), of electron radiation with matter (slowing down, Cherenkov radiation, backscattering, absorption, annihilation), and of gamma radiation with matter (Compton effect, photoelectric effect, pair formation, absorption) are discussed. The reacting constituents are categorized as shell electrons, atomic nuclei, the Coulomb field of nuclei. In the complex interactions, the Auger effect and the photoelectron-induced bremsstrahlung is discussed. (R.P.)
Asymmetric dark matter from spontaneous cogenesis in the supersymmetric standard model
Energy Technology Data Exchange (ETDEWEB)
Kamada, Kohei [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Yamaguchi, Masahide [Tokyo Institute of Technology (Japan). Dept. of Physics
2012-01-15
The observational relation between the density of baryon and dark matter in the Universe, {omega}{sub DM}/{omega}{sub B}{approx_equal}5, is one of the most difficult problems to solve in modern cosmology. We discuss a scenario that explains this relation by combining the asymmetric dark matter scenario and the spontaneous baryogenesis associated with the flat direction in the supersymmetric standard model. A part of baryon asymmetry is transferred to charge asymmetry D that dark matter carries, if a symmetry violating interaction that works at high temperature breaks not only B-L but also D symmetries simultaneously. In this case, the present number density of baryon and dark matter can be same order if the symmetric part of dark matter annihilates sufficiently. Moreover, the baryon number density can be enhanced as compared to that of dark matter if another B-L violating interaction is still in thermal equilibrium after the spontaneous genesis of dark matter, which accommodates a TeV scale asymmetric dark matter model. (orig.)
Unifying Asymmetric Inert Fermion Doublet Dark Matter and Leptogenesis with Neutrino Mass
Sahu, Narendra
2012-01-01
We propose a scalar Triplet extension of the standard model (SM) to unify the origin of neutrino mass with the visible and dark matter component of the Universe. We assume that the scalar triplet is super heavy, so that its CP-violating out-of-equilibrium decay in the early Universe not only produce asymmetric dark matter which is the neutral component of an additional vector like fermion doublet, but also give rise to lepton asymmetry. The latter gets converted to observed baryon asymmetry via B+L violating sphaleron processes. Below electroweak phase transition the scalar triplet acquires a vacuum expectation value and give rise to sub-eV Majorana masses to three flavors of active neutrinos. Thus an unification of the origin of neutrino mass, lepton asymmetry and asymmetric dark matter is achieved within a scalar triplet extension of the SM.
Asymmetric Dark Matter and CP Violating Scatterings in a UV Complete Model
Baldes, Iason; Millar, Alexander J; Volkas, Raymond R
2015-01-01
We explore possible asymmetric dark matter models using CP violating scatterings to generate an asymmetry. In particular, we introduce a new model, based on DM fields coupling to the SM Higgs and lepton doublets, $\\overline{L}H$, and explore its UV completions. We study the CP violation and asymmetry formation of this model, to demonstrate that it is capable of producing the correct abundance of dark matter and the observed matter-antimatter asymmetry. Crucial to achieving this is the introduction of interactions which violate CP with a $T^{2}$ dependence.
Skyrmions, dense matter and nuclear forces
International Nuclear Information System (INIS)
A simple introduction to a number of properties of Skyrme's chiral soliton model of baryons is given. Some implications of the model for dense matter and for nuclear interactions are discussed. (orig.)
Relativistic thermal conductivity of nuclear matter
International Nuclear Information System (INIS)
The thermal conductivity of nuclear matter is calculated using relativistic finite-temperature Green's functions. The interactions between nucleons are modelled by one-pion exchange. Comparison is made to the non-relativistic calculation of Tomonaga. (author)
Charge symmetry breaking in nuclear matter
International Nuclear Information System (INIS)
The effect of charge symmetry breaking (CSB) is investigated in nuclear matter with the isospin mixing of neutral vector mesons. The equations of motion are solved by the relativistic mean field approximation. (author)
Heavy Mesons in Nuclear Matter and Nuclei
Tolos, Laura; Garcia-Recio, Carmen; Molina, Raquel; Nieves, Juan; Oset, Eulogio; Ramos, Angels; Romanets, Olena; Salcedo, Lorenzo Luis; Torres-Rincon, Juan M
2014-01-01
Heavy mesons in nuclear matter and nuclei are analyzed within different frameworks, paying a special attention to unitarized coupled-channel approaches. Possible experimental signatures of the properties of these mesons in matter are addressed, in particular in connection with the future FAIR facility at GSI.
Nuclear shock waves and quark matter
International Nuclear Information System (INIS)
Atomic nuclei colliding with each other in a particle accelerator at extremely high velocities undergo interactions which lead to novel states of matter. The equation of state of this hot, dense nuclear matter reveals information on the processes occurring in a supernova, and on the big bang at the origin of the universe. (orig.)
Inhomogeneous chiral symmetry breaking phases in isospin-asymmetric matter
Nowakowski, Daniel; Carignano, Stefano; Wambach, Jochen
2015-01-01
We investigate the effects of isospin asymmetry on inhomogeneous chiral symmetry breaking phases within the two-flavor NJL model. After introducing a plane-wave ansatz for each quark-flavor condensate, we find that, as long as their periodicities are enforced to be equal, a non-zero isospin chemical potential shrinks the size of the inhomogeneous phase. The asymmetry reached in charge neutral matter is nevertheless not excessively large, so that an inhomogeneous window is still present in the phase diagram. Lifting the constraint of equal periodicities alters the picture significantly, as the inhomogeneous phase survives in a much larger region of the phase diagram.
Collective modes in strange and isospin-asymmetric hadronic matter
International Nuclear Information System (INIS)
We study the propagation of non-strange and strange meson modes in hadronic matter considering both isospin and strangeness mixing induced by quantum fluctuations in the medium. Baryons are described using the quark-meson coupling model extended to include interactions of strange quarks. In particular, we evaluate the dependence of the meson masses on the baryonic density, the strangeness fraction and the isospin asymmetry of the medium. We have found a considerable admixture of strangeness and isospin in the ?-mode in the high density regime
Nuclear matter in all its states
International Nuclear Information System (INIS)
This report includes the nine lectures which have been presented at the Joliot-Curie School of Nuclear Physics in 1985. The subjects covered are the following: thermodynamic description of excited nuclei; heavy ion reactions at high energy (theoretical approach); heavy ion reactions at high energy (experimental approach); relativistic nuclear physics and quark effects in nuclei; quark matter; nuclear compressibility and its experimental determinations; hot nuclei; anti p-nucleus interaction; geant resonances at finite temperature
Relativity damps OPEP in nuclear matter
International Nuclear Information System (INIS)
Using a relativistic Dirac-Brueckner analysis the OPEP contribution to the ground state energy of nuclear matter is studied. In the study the pion is derivative-coupled. The author finds that the role of the tensor force in the saturation mechanism is substantially reduced compared to its dominant role in a usual nonrelativistic treatment. He shows that the damping of derivative-coupled OPEP is actually due to the decrease of M*/M with increasing density. He points out that if derivative-coupled OPEP is the preferred form of nuclear effective lagrangian nonrelativistic treatment of nuclear matter is in trouble. Lacking the notion of M* it cannot replicate the damping. He suggests an examination of the feasibility of using pseudoscalar coupled ?N interaction before reaching a final conclusion about nonrelativistic treatment of nuclear matter
Cosmic ray-dark matter scattering: a new signature of (asymmetric) dark matter in the gamma ray sky
International Nuclear Information System (INIS)
We consider the process of scattering of Galactic cosmic-ray electrons and protons off of dark matter with the radiation of a final-state photon. This process provides a novel way to search for Galactic dark matter with gamma rays. We argue that for a generic weakly interacting massive particle, barring effects such as co-annihilation or a velocity-dependent cross section, the gamma-ray emission from cosmic-ray scattering off of dark matter is typically smaller than that from dark matter pair-annihilation. However, if dark matter particles cannot pair-annihilate, as is the case for example in asymmetric dark matter scenarios, cosmic-ray scattering with final state photon emission provides a unique window to detect a signal from dark matter with gamma rays. We estimate the expected flux level and its spectral features for a generic supersymmetric setup, and we also discuss dipolar and luminous dark matter. We show that in some cases the gamma-ray emission might be large enough to be detectable with the Fermi Large Area Telescope
Light Asymmetric Dark Matter on the Lattice: SU(2) Technicolor with Two Fundamental Flavors
DEFF Research Database (Denmark)
Lewis, Randy; Pica, Claudio
2012-01-01
The SU(2) gauge theory with two massless Dirac flavors constitutes the building block of several models of Technicolor. Furthermore it has also been used as a template for the construction of a natural light asymmetric, or mixed type, dark matter candidate. We use explicit lattice simulations to confirm the pattern of chiral symmetry breaking by determining the Goldstone spectrum and therefore show that the dark matter candidate can, de facto, be constituted by a complex Goldstone boson. We also determine the phenomenologically relevant spin one and spin zero isovector spectrum and demonstrate that it is well separated from the Goldstone spectrum.
Big Bang Synthesis of Nuclear Dark Matter
Hardy, Edward; March-Russell, John; West, Stephen M
2014-01-01
We investigate the physics of dark matter models featuring composite bound states carrying a large conserved dark "nucleon" number. The properties of sufficiently large dark nuclei may obey simple scaling laws, and we find that this scaling can determine the number distribution of nuclei resulting from Big Bang Dark Nucleosynthesis. For plausible models of asymmetric dark matter, dark nuclei of large nucleon number, e.g. > 10^8, may be synthesised, with the number distribution taking one of two characteristic forms. If small-nucleon-number fusions are sufficiently fast, the distribution of dark nuclei takes on a logarithmically-peaked, universal form, independent of many details of the initial conditions and small-number interactions. In the case of a substantial bottleneck to nucleosynthesis for small dark nuclei, we find the surprising result that even larger nuclei, with size >> 10^8, are often finally synthesised, again with a simple number distribution. We briefly discuss the constraints arising from the...
Chiral Quark Dynamics in Dense Nuclear Matter
Forkel, Hilmar
1994-01-01
We consider a new approach to the description of dense nuclear matter in the framework of chirally symmetric, quark-based hadron models. As previously in the Skyrme model, the dense environment is described in terms of hyperspherical cells of unit baryon number. The intrinsic curvature of these cells generates a new gauge interaction for the quark fields which mediates interactions with the ambient matter. We apply this approach to the Nambu-Jona-Lasinio (NJL) model, constru...
Moments of $\\phi$ meson spectral functions in vacuum and nuclear matter
Gubler, Philipp
2015-01-01
Moments of the $\\phi$ meson spectral function in vacuum and in nuclear matter are analyzed, combining a model based on chiral SU(3) effective field theory (with kaonic degrees of freedom) and finite-energy QCD sum rules. For the vacuum we show that the spectral density is strongly constrained by a recent accurate measurement of the $e^+ e^- \\to K^+ K^-$ cross section. In nuclear matter the $\\phi$ spectrum is modified by interactions of the decay kaons with the surrounding nuclear medium, leading to a significant broadening and an asymmetric deformation of the $\\phi$ meson peak. We demonstrate that both in vacuum and nuclear matter, the first two moments of the spectral function are compatible with finite-energy QCD sum rules. A brief discussion of the next-higher spectral moment involving strange four-quark condensates is also presented.
Holographic cold nuclear matter and neutron star
Ghoroku, Kazuo; Tachibana, Motoi; Toyoda, Fumihiko
2013-01-01
We have previously found a new phase of cold nuclear matter based on a holographic gauge theory, where baryons are introduced as instanton gas in the probe D8/$\\overline{\\rm D8}$ branes. In our model, we could obtain the equation of state (EOS) of our nuclear matter by introducing fermi momentum. Then, here we apply this model to the neutron star and study its mass and radius by solving the Tolman-Oppenheimer-Volkoff (TOV) equations in terms of the EOS given here. We give some comments for our holographic model from a viewpoint of the other field theoretical approaches.
The exploration of hot nuclear matter.
Jacak, Barbara V; Müller, Berndt
2012-07-20
When nuclear matter is heated beyond 2 trillion degrees, it becomes a strongly coupled plasma of quarks and gluons. Experiments using highly energetic collisions between heavy nuclei have revealed that this new state of matter is a nearly ideal, highly opaque liquid. A description based on string theory and black holes in five dimensions has made the quark-gluon plasma an archetypical strongly coupled quantum system. Open questions about the structure and theory of the quark-gluon plasma are under active investigation. Many of the insights are also relevant to ultracold fermionic atoms and strongly correlated condensed matter. PMID:22822143
Light vector mesons in nuclear matter
International Nuclear Information System (INIS)
We summarize the current theoretical and experimental status of the spectral changes of vector mesons (?, ?, ?) in nuclear medium. Various approaches, including QCD sum rules, effective theory of hadrons and bag models show the decrease of vector meson masses in nuclear matter. The possibility to detect the mass shift through lepton pairs in ?-A, p-A and A-A reactions is also discussed. (author). 74 refs
Nuclear physics of hot dense matter
International Nuclear Information System (INIS)
The equation of state of hot dense matter is an essential ingredient to describe the gravitational contraction of massive stars. Some of the nuclear physics problems occurring in the determination of the equation of state of hot dense matter are discussed. This particularly rich domain of nuclear physics deals with very unusual nuclei, whose mass numbers can be sometimes as large as a thousand, whose existence becomes possible in dense matter because of the screening of Coulomb forces. A calculation of the properties of hot nuclear matter in the mean field approximation is presented. It is shown that a useful approximation to study the phase equilibrium equations is to consider low temperature expansions for the nucleus expansions for the vapor. A simple formula is derived for the limiting temperature TL beyond which nuclei no longer exist. The equation of state is discussed at subnuclear density and in the domain densities greater than the nuclear saturation density. The standard methods of non relativistic many-body theory as well as relativistic mean-field and Dirac-Brueckner approaches are also discussed. (K.A.) 70 refs., 9 figs
Nuclear matter in heavy ion collisions
International Nuclear Information System (INIS)
In this report the measurement of the inclusive production of negative pions and protons in reactions of 40Ar with KCl at 1.8 GeV/nucleon is described. The measured energy spectra and multiplicities are presented and discussed regarding the stopping power of nuclear matter. (HSI)
Condensed matter studies by nuclear methods
International Nuclear Information System (INIS)
The separate abstract was prepared for 1 of the papers in this volume. The remaining 13 papers dealing with the use but not with advances in the use of nuclear methods in studies of condensed matter, were considered outside the subject scope of INIS. (M.F.W.)
Resonance properties in nuclear matter
International Nuclear Information System (INIS)
We analyze the formation and decay properties of nucleon resonances formed in heavy-ion collisions at 1--2 GeV/u within a microscopic transport approach. In case of Au+Au reactions the density of ? resonances reaches 0.15 fm-3 in the central cell for a time period of the order of 10 fm/c such that one can legitimately speak about resonance matter. The lifetime of the ?'s is found to be shortened at high density by only 20% due to the in-medium channel ?+N?N+N
The $\\alpha$-particle in nuclear matter
Beyer, M; Kuhrts, C; Röpke, G; Schuck, P
2000-01-01
Among the light nuclear clusters the alpha-particle is by far the strongest bound system and therefore expected to play a significant role in the dynamics of nuclei and the phases of nuclear matter. To systematically study the properties of the alpha-particle we have derived an effective four-body equation of the Alt-Grassberger-Sandhas (AGS) type that includes the dominant medium effects, i.e. self energy corrections and Pauli-blocking in a consistent way. The equation is solved utilizing the energy dependent pole expansion for the sub system amplitudes. We find that the Mott transition of an alpha-particle at rest differs from that expected from perturbation theory and occurs at approximately 1/10 of nuclear matter densities.
The public and nuclear matters
International Nuclear Information System (INIS)
The nuclear industry has an image problem and is facing a major crisis of public confidence. The solution lies not merely in better public relations and advertising campaigns, but in a fundamental reassessment of electricity management, a comprehensive re-examination of the economics of electricity use and generation and, in all probability, a shift towards more public-friendly reactor designs. Over the next decade the industry faces two great forces: the power of public opinion and the momentum of inherent technological advance. Somehow these two elements have to be guided so that they complement each other. This article aims to show how this might be achieved. (author)
Probing Cold Dense Nuclear Matter
Subedi, R; Monaghan, P; Anderson, B D; Aniol, K; Annand, J; Arrington, J; Benaoum, H; Benmokhtar, F; Bertozzi, W; Boeglin, W; Chen, J -P; Choi, Seonho; Cisbani, E; Craver, B; Frullani, S; Garibaldi, F; Gilad, S; Gilman, R; Glamazdin, O; Hansen, J -O; Higinbotham, D W; Holmstrom, T; Ibrahim, H; Igarashi, R; De Jager, C W; Jans, E; Jiang, X; Kaufman, L; Kelleher, A; Kolarkar, A; Kumbartzki, G; LeRose, J J; Lindgren, R; Liyanage, N; Margaziotis, D J; Markowitz, P; Marrone, S; Mazouz, M; Meekins, D; Michaels, R; Moffit, B; Perdrisat, C F; Piasetzky, E; Potokar, M; Punjabi, V; Qiang, Y; Reinhold, J; Ron, G; Rosner, G; Saha, A; Sawatzky, B; Shahinyan, A; Širca, S; Slifer, K; Solvignon, P; Sulkosky, V; Urciuoli, G; Voutier, E; Watson, J W; Weinstein, L B; Wojtsekhowski, B; Wood, S; Zheng, X -C; Zhu, L; 10.1126/science.1156675
2009-01-01
The protons and neutrons in a nucleus can form strongly correlated nucleon pairs. Scattering experiments, where a proton is knocked-out of the nucleus with high momentum transfer and high missing momentum, show that in 12C the neutron-proton pairs are nearly twenty times as prevalent as proton-proton pairs and, by inference, neutron-neutron pairs. This difference between the types of pairs is due to the nature of the strong force and has implications for understanding cold dense nuclear systems such as neutron stars.
Probing Cold Dense Nuclear Matter
Energy Technology Data Exchange (ETDEWEB)
Subedi, Ramesh; Shneor, R.; Monaghan, Peter; Anderson, Bryon; Aniol, Konrad; Annand, John; Arrington, John; Benaoum, Hachemi; Benmokhtar, Fatiha; Bertozzi, William; Boeglin, Werner; Chen, Jian-Ping; Choi, Seonho; Cisbani, Evaristo; Craver, Brandon; Frullani, Salvatore; Garibaldi, Franco; Gilad, Shalev; Gilman, Ronald; Glamazdin, Oleksandr; Hansen, Jens-Ole; Higinbotham, Douglas; Holmstrom, Timothy; Ibrahim, Hassan; Igarashi, Ryuichi; De Jager, Cornelis; Jans, Eddy; Jiang, Xiaodong; Kaufman, Lisa; Kelleher, Aidan; Kolarkar, Ameya; Kumbartzki, Gerfried; LeRose, John; Lindgren, Richard; Liyanage, Nilanga; Margaziotis, Demetrius; Markowitz, Pete; Marrone, Stefano; Mazouz, Malek; Meekins, David; Michaels, Robert; Moffit, Bryan; Perdrisat, Charles; Piasetzky, Eliazer; Potokar, Milan; Punjabi, Vina; Qiang, Yi; Reinhold, Joerg; Ron, Guy; Rosner, Guenther; Saha, Arunava; Sawatzky, Bradley; Shahinyan, Albert; Sirca, Simon; Slifer, Karl; Solvignon, Patricia; Sulkosky, Vince; Sulkosky, Vincent; Sulkosky, Vince; Sulkosky, Vincent; Urciuoli, Guido; Voutier, Eric; Watson, John; Weinstein, Lawrence; Wojtsekhowski, Bogdan; Wood, Stephen; Zheng, Xiaochao; Zhu, Lingyan
2008-06-01
The protons and neutrons in a nucleus can form strongly correlated nucleon pairs. Scattering experiments, in which a proton is knocked out of the nucleus with high-momentum transfer and high missing momentum, show that in carbon-12 the neutron-proton pairs are nearly 20 times as prevalent as proton-proton pairs and, by inference, neutron-neutron pairs. This difference between the types of pairs is due to the nature of the strong force and has implications for understanding cold dense nuclear systems such as neutron stars.
Probing Cold Dense Nuclear Matter
International Nuclear Information System (INIS)
The protons and neutrons in a nucleus can form strongly correlated nucleon pairs. Scattering experiments, in which a proton is knocked out of the nucleus with high-momentum transfer and high missing momentum, show that in carbon-12 the neutron-proton pairs are nearly 20 times as prevalent as proton-proton pairs and, by inference, neutron-neutron pairs. This difference between the types of pairs is due to the nature of the strong force and has implications for understanding cold dense nuclear systems such as neutron stars.
Nuclear matter fourth-order symmetry energy in relativistic mean field models
Cai, Bao-Jun
2011-01-01
Within the nonlinear relativistic mean field model, we derive the analytical expression of the nuclear matter fourth-order symmetry energy $E_{4}(\\rho)$. Our results show that the value of $E_{4}(\\rho)$ at normal nuclear matter density $\\rho_{0}$ is generally less than 1 MeV, confirming the empirical parabolic approximation to the equation of state for asymmetric nuclear matter at $\\rho_{0}$. On the other hand, we find that the $E_{4}(\\rho)$ may become nonnegligible at high densities. Furthermore, the analytical form of the $E_{4}(\\rho)$ provides the possibility to study the higher-order effects on the isobaric incompressibility of asymmetric nuclear matter, i.e., $K_{\\mathrm{sat}}(\\delta)=K_{0}+K_{\\mathrm{{sat},2}}\\delta ^{2}+K_{\\mathrm{{sat},4}}\\delta ^{4}+\\mathcal{O}(\\delta ^{6})$ where $\\delta =(\\rho_{n}-\\rho_{p})/\\rho $ is the isospin asymmetry, and we find that the value of $K_{\\mathrm{{sat},4}}$ is generally comparable with that of the $K_{\\mathrm{{sat},2}}$. In addition, we study the effects of the $E...
Quartic isospin asymmetry energy of nuclear matter from chiral pion-nucleon dynamics
Kaiser, N
2015-01-01
Based on a chiral approach to nuclear matter, we calculate the quartic term in the expansion of the equation of state of isospin-asymmetric nuclear matter. The contributions to the quartic isospin asymmetry energy $A_4(k_f)$ arising from $1\\pi$-exchange and chiral $2\\pi$-exchange in nuclear matter are calculated analytically together with three-body terms involving virtual $\\Delta(1232)$-isobars. From these interaction terms one obtains at saturation density $\\rho_0 = 0.16\\,$fm$^{-3}$ the value $A_4(k_{f0})= 1.5\\,$MeV, more than three times as large as the kinetic energy part. Moreover, iterated $1\\pi$-exchange exhibits components for which the fourth derivative with the respect to the isospin asymmetry parameter $\\delta$ becomes singular at $\\delta =0$. The genuine presence of a non-analytical term $\\delta^4 \\ln|\\delta|$ in the expansion of the energy per particle of isospin-asymmetric nuclear matter is demonstrated by evaluating a s-wave contact interaction at second order.
Towards Nuclear Physics of OHe Dark Matter
Khlopov, Maxim Yu; Soldatov, Evgeny Yu
2011-01-01
The nonbaryonic dark matter of the Universe can consist of new stable charged particles, bound in heavy "atoms" by ordinary Coulomb interaction. If stable particles $O^{--}$ with charge -2 are in excess over their antiparticles (with charge +2), the primordial helium, formed in Big Bang Nucleosynthesis, captures all $O^{--}$ in neutral "atoms" of O-helium (OHe). Interaction with nuclei plays crucial role in the cosmological evolution of OHe and in the effects of these dark atoms as nuclear interacting dark matter. Slowed down in terrestrial matter OHe atoms cause negligible effects of nuclear recoil in underground detectors, but can experience radiative capture by nuclei. Local concentration of OHe in the matter of detectors is rapidly adjusted to the incoming flux of cosmic OHe and possess annual modulation due to Earth's orbital motion around the Sun. The potential of OHe-nucleus interaction is determined by polarization of OHe by the Coulomb and nuclear force of the approaching nucleus. Stark-like effect b...
Chiral density wave in nuclear matter
International Nuclear Information System (INIS)
Inspired by recent work on inhomogeneous chiral condensation in cold, dense quark matter within models featuring quark degrees of freedom, we investigate the chiral density-wave solution in nuclear matter at zero temperature and nonvanishing baryon number density in the framework of the so-called extended linear sigma model (eLSM). The eLSM is an effective model for the strong interaction based on the global chiral symmetry of quantum chromodynamics (QCD). It contains scalar, pseudoscalar, vector, and axial-vector mesons as well as baryons. In the latter sector, the nucleon and its chiral partner are introduced as parity doublets in the mirror assignment. The eLSM simultaneously provides a good description of hadrons in vacuum as well as nuclear matter ground-state properties. We find that an inhomogeneous phase in the form of a chiral density wave is realized, but only for densities larger than 2.4?0, where ?0 is the nuclear matter ground-state density
Possible indication of momentum-dependent asymmetric dark matter in the sun.
Vincent, Aaron C; Scott, Pat; Serenelli, Aldo
2015-02-27
Broad disagreement persists between helioseismological observables and predictions of solar models computed with the latest surface abundances. Here we show that most of these problems can be solved by the presence of asymmetric dark matter coupling to nucleons as the square of the momentum q exchanged in the collision. We compute neutrino fluxes, small frequency separations, surface helium abundances, sound speed profiles, and convective zone depths for a number of models, showing more than a 6? preference for q^{2} models over others, and over the standard solar model. The preferred mass (3 GeV) and reference dark matter-nucleon cross section (10^{-37}??cm^{2} at q_{0}=40??MeV) are within the region of parameter space allowed by both direct detection and collider searches. PMID:25768751
Possible Indication of Momentum-Dependent Asymmetric Dark Matter in the Sun
Vincent, Aaron C.; Scott, Pat; Serenelli, Aldo
2015-02-01
Broad disagreement persists between helioseismological observables and predictions of solar models computed with the latest surface abundances. Here we show that most of these problems can be solved by the presence of asymmetric dark matter coupling to nucleons as the square of the momentum q exchanged in the collision. We compute neutrino fluxes, small frequency separations, surface helium abundances, sound speed profiles, and convective zone depths for a number of models, showing more than a 6 ? preference for q2 models over others, and over the standard solar model. The preferred mass (3 GeV) and reference dark matter-nucleon cross section (10-37 cm2 at q0=40 MeV ) are within the region of parameter space allowed by both direct detection and collider searches.
D-mesons and charmonium states in hot isospin asymmetric strange hadronic matter
International Nuclear Information System (INIS)
The study of the medium modifications of hadrons is an important topic of research in strong interaction physics, which is of relevance in the heavy-ion collision experiments as well as in nuclear astrophysics. The study of the mass modifications of D mesons is relevant in understanding their production as well as collective flow in the heavy-ion collision experiments. The present paper is devoted to the study of medium modifications of D mesons in isospin asymmetric strange hadronic medium at finite temperatures
The microscopic approach to nuclear matter and neutron star matter
International Nuclear Information System (INIS)
We review a variety of theoretical and experimental investigations aimed at improving our knowledge of the nuclear matter equation of state. Of particular interest are nuclear matter extreme states in terms of density and/or isospin asymmetry. The equation of state of matter with unequal concentrations of protons and neutrons has numerous applications. These include heavy-ion collisions, the physics of rare, short-lived nuclei and, on a dramatically different scale, the physics of neutron stars. The "common denominator" among these (seemingly) very different systems is the symmetry energy, which plays a crucial role in both the formation of the neutron skin in neutron-rich nuclei and the radius of a neutron star (a system 18 orders of magnitude larger and 55 orders of magnitudes heavier). The details of the density dependence of the symmetry energy are not yet sufficiently constrained. Throughout this article, our emphasis will be on the importance of adopting a microscopic approach to the many-body problem, which we believe to be the one with true predictive power. (author)
Neutron-Proton Mass Difference in Nuclear Matter and in Finite Nuclei and the Nolen-Schiffer Anomaly
Yakhshiev U.T.; Wirzba A.; Rakhimov A.M.; Meißner U.-G.
2010-01-01
The neutron-proton mass difference in (isospin asymmetric) nuclear matter and finite nuclei is studied in the framework of a medium-modified Skyrme model. The proposed effective Lagrangian incorporates both the medium influence of the surrounding nuclear environment on the single nucleon properties and an explicit isospin-breaking effect in the mesonic sector. Energy-dependent charged and neutral pion optical potentials in the s- and p-wave channels are included as well. The...
Anatomy of symmetry energy of dilute nuclear matter
De, J N; Agrawal, B K
2010-01-01
The symmetry energy coefficients of dilute clusterized nuclear matter are evaluated in the $S$-matrix framework. Employing a few different definitions commonly used in the literature for uniform nuclear matter, it is seen that the different definitions lead to perceptibly different results for the symmetry coefficients for dilute nuclear matter. They are found to be higher compared to those obtained for uniform matter in the low density domain. The calculated results are in reasonable consonance with those extracted recently from experimental data.
Controllable Asymmetric Matter-wave Beam Splitter and Ring Potential on an Atom Chip
Kim, S J; Gang, S T; Anderson, D; Kim, J B
2015-01-01
We have constructed an asymmetric matter-wave beam splitter and a ring potential on an atom chip with Bose-Einstein condensates using radio-frequency dressing. By applying rf-field parallel to the quantization axis in the vicinity of the static trap minima added to perpendicular rf-fields, versatile controllability on the potentials is realized. Asymmetry of the rf-induced double well is manipulated without discernible displacement of the each well along horizontal and vertical direction. Formation of an isotropic ring potential on an atom chip is achieved by compensating the gradient due to gravity and inhomogeneous coupling strength. In addition, position and rotation velocity of a BEC along the ring geometry are controlled by the relative phase and the frequency difference between the rf-fields, respectively.
History of the nuclear matter safety and control law
International Nuclear Information System (INIS)
In this text we give the history of the law creation on the control and safety of nuclear matter. Initially based on the CEA regulation single owner of nuclear matter, the development of nuclear energy has conducted the French government to edict law in relation with IAEA and Euratom recommendations
Stellar properties and nuclear matter constraints
Dutra, Mariana; Menezes, Débora P
2015-01-01
We have analyzed stellar properties of the relativistic mean-field (RMF) parametrizations shown to be consistent with the recently studied constraints related to nuclear matter, pure neutron matter, symmetry energy and its derivatives [Dutra et al., Phys. Rev. C 90, 055203 (2014)]. Our results show that only two RMF parametrizations do not allow the emergence of the direct Urca process, important aspect regarding the evolution of a neutron star. Moreover, among all approved RMF models, fourteen of them produce neutron stars with maximum masses inside the range $1.93\\leqslant M/M_\\odot\\leqslant 2.05$, with $M_\\odot$ being the solar mass. Only three models yield maximum masses above this range and a discussion on the inclusion of hyperons is presented. Finally, we have verified that the models satisfying the neutron star maximum mass constraint do not observe the squared sound velocity bound, namely, $v_s^2 < 1/3$, corroborating recent findings.
Neutrino neutral current interactions in nuclear matter
International Nuclear Information System (INIS)
Detailed knowledge of neutrino transport properties in matter is crucial for an understanding of the evolution of supernovae and of neutron star cooling. We investigate screening of neutrino scattering from a dense degenerate gas of electrons, protons and neutrons. We take into account correlations induced by the Coulomb interactions of the electrons and protons, and the strong interactions of the protons and neutrons. Nuclear matter is described by the ?? model of quantum hadrodynamics. Results are presented for typical astrophysical scenarios. The differential cross section is strongly reduced at large energy transfer, where electrons dominate, and slightly reduced for small energy transfer, where nucleons dominate. At large densities, the nucleon effective mass is considerably lower than the free mass, and the region dominated by nucleons extends to larger energy transfer than for free nucleons. (orig.)
Chiral quark dynamics in dense nuclear matter
Forkel, H
1995-01-01
We consider a new approach to the description of dense nuclear matter in the framework of chirally symmetric, quark-based hadron models. As previously in the Skyrme model, the dense environment is described in terms of hyperspherical cells of unit baryon number. The intrinsic curvature of these cells generates a new gauge interaction for the quark fields which mediates interactions with the ambient matter. We apply this approach to the Nambu-Jona-Lasinio (NJL) model, construct its curved-space quark propagator and solve the ladder Bethe-Salpeter equation for the pion. We find a high-density phase transition to chiral restoration, discuss the density dependence of the chiral order parameter and of the pion properties, and compare with results of the conventional chemical-potential approach. The new approach can additionally describe baryon-density-free cavities in the dense medium.
Mass shift of ?-meson in nuclear matter
International Nuclear Information System (INIS)
The propagation of ?-meson in nuclear matter is studied in the Walecka model, by assuming that sigma couples to a pair of nucleon-antinucleon states to particle-hole states. The in-medium effect of ?-? mixing is also studied. For completeness, the coupling of sigma to two virtual pions was also considered. It is found that the ?-meson mass decreases with respect to its value in vacuum and that the contribution of the ?-? mixing effect on the mass shift is relatively small. (author)
Hadronization measurements in cold nuclear matter
Energy Technology Data Exchange (ETDEWEB)
Dupre, Raphael [IPN Orsay; et. al.,
2015-05-01
Hadronization is the non-perturbative process of QCD by which partons become hadrons. It has been studied at high energies through various processes, we focus here on the experiments of lepto-production of hadrons in cold nuclear matter. By studying the dependence of observables to the atomic number of the target, these experimentscan give information on the dynamic of the hadronization at the femtometer scale. In particular, we will present preliminary results from JLab Hall B (CLAS collaboration), which give unprecedented statistical precision. Then, we will present results of a phenomenological study showing how HERMES data can be described with pure energyloss models.
Spin-isospin stability of nuclear matter
Kaiser, N
2006-01-01
We calculate the density-dependent spin-isospin asymmetry energy $J(k_f)$ of nuclear matter in the three-loop approximation of chiral perturbation theory. The interaction contributions to $J(k_f)$ originate from one-pion exchange, iterated one-pion exchange, and irreducible two-pion exchange with no, single, and double virtual $\\Delta$-isobar excitation. We find that the approximation to $1\\pi$-exchange and iterated $1\\pi$-exchange terms (which leads already to a good nuclea...
Collective nuclear flow and shadowing by spectator matter
Raschke, Ansgar Egon,
1998-01-01
Extreme states of matter are studied in collisions of heavy nuclei. In this thesis the behaviour of hot and compressed nuclear matter was investigated. The distribution of particles emitted from the collision zone is analyzed. Conclusions are drawn with respect to the interplay of cold matter outside the reaction zone and hot matter from the core of the interaction region. ... Zie: Summary
Nuclear target effect on dark matter detection rate
Bednyakov, V. A.; Simkovic, F.
2005-01-01
Expected event rates for a number of dark matter nuclear targets were calculated in the effective low-energy minimal supersymmetric standard model, provided the lightest neutralino is the dark matter Weakly Interacting Massive Particle (WIMP). These calculations allow direct comparison of sensitivities of different dark matter detectors to intermediate mass WIMPs expected from the measurements of the DArk MAtter (DAMA) experiment.
Stability of nuclear matter against neutral pion condensation
International Nuclear Information System (INIS)
The global stability of the uniform ground state of nuclear matter is tested relative to a ?0-condensed state characterized by static spin-(isospin-)waves. Strong nuclear correlations are introduced into the trial wave functions for each phase, thereby permitting models of the realistic two-nucleon force to be employed. In low cluster-order comparison, the uniform phases of symmetrical nuclear matter and neutron matter are emphatically favored over the entire density range considered. (orig.)
The few scales of nuclei and nuclear matter
Delfino, A; Frederico, T; Timoteo, V. S.; Tomio, Lauro
2007-01-01
The well-known correlations of low-energy three and four-nucleon observables with a typical three-nucleon scale (e.g., the Tjon line) is extended to light nuclei and nuclear matter. Evidence for the scaling between light nuclei binding energies and the triton one are pointed out. We argue that the saturation energy and density of nuclear matter are correlated to the triton binding energy. The available systematic nuclear matter calculations indicate a possible band structure...
Inhomogeneous phases of isospin-asymmetric matter in the Nambu-Jona-Lasinio model
International Nuclear Information System (INIS)
We investigate the phase structure of strong-interaction matter within a two-flavor Nambu-Jona-Lasinio model. Earlier it has been shown for degenerate quark flavors that chiral symmetry-breaking phases with spatially modulated order-parameters can occur. We analyze the emergence of these inhomogeneous phases in isospin-asymmetric matter by extending the model through an additional isospin chemical potential, however restricting the order-parameter to be spatially modulated in only one dimension. It is found that for a non-vanishing isospin chemical potential the formation of inhomogeneous chiral symmetry-breaking phases is disfavored, when enforcing equal periodicities for the up and down quarks and neglecting charged pion condensation. If the periodicities of the quarks are not limited to be of the same magnitude, inhomogeneous chiral symmetry-breaking phases are found to be less sensitive to the additional pairing stress and can occur in a larger domain of the phase diagram. As an outlook we discuss possible extensions, like the addition of inhomogeneous charged pion condensation or color superconductivity.
Recent Advances in Microscopic Approaches to Nuclear Matter and Symmetry Energy
Directory of Open Access Journals (Sweden)
Francesca Sammarruca
2014-10-01
Full Text Available Nuclear matter is a convenient theoretical laboratory to test many-body theories. When neutron and proton densities are different, the isospin dependence of the nuclear force gives rise to the symmetry energy term in the equation of state. This quantity is a crucial mechanism in the formation of the neutron skin in nuclei, as well as in other systems and phenomena involved in the dynamics of neutrons and protons in neutron-rich systems, such as isospin-asymmetric heavy-ion collisions. In this article, we will review phenomenological facts about the symmetry energy and recent experimental efforts to constrain its density dependence and related quantities. We will then review our microscopic approach to the equation of state of symmetric and asymmetric nuclear matter and present a corresponding set of predictions. Our calculations utilize the Dirac–Brueckner–Hartree–Fock method and realistic meson-theoretic nucleon-nucleon potentials. Chiral perturbation theory is an alternative approach, based on a well-defined scheme, which allows one to develop nuclear forces at each order of the chiral expansion. We will present and discuss predictions based on chiral perturbation theory, where we employ consistent two- and three-body chiral interactions. Throughout the article, one of the focal points is the importance of pursuing ab initio methods towards a deeper understanding of the many-body system.
Quark distributions in nuclear matter and the EMC effect
Mineo, H.; Bentz, W.; Ishii, N.; Thomas, A.W.(ARC Centre of Excellence for Particle Physics at the Terascale and CSSM, School of Chemistry and Physics, The University of Adelaide, Australia); Yazaki, K
2003-01-01
Quark light cone momentum distributions in nuclear matter and the structure function of a bound nucleon are investigated in the framework of the Nambu-Jona-Lasinio model. This framework describes the nucleon as a relativistic quark-diquark state, and the nuclear matter equation of state by using the mean field approximation. The scalar and vector mean fields in the nuclear medium couple to the quarks in the nucleon and their effect on the spin independent nuclear structure f...
Hirschegg '95: Dynamical properties of hadrons in nuclear matter. Proceedings
International Nuclear Information System (INIS)
The following topics were dealt with: Chiral symmetry, chiral condensates, in-medium effective chiral Lagrangians, ?'s in nuclei, nonperturbative QCD, electron scattering from nuclear matter, nuclear shadowing, QCD sum rules, deconfinement, ultrarelativistic heavy ion collisions, nuclear dimuon and electron pair production, photoproduction from nuclei, subthreshold K+ production, kaon polarization in nuclear matter, charged pion production in relativistic heavy ion collisions, the Nambu-Jona-Lasinio model, the SU(3)LxSU(3)R sigma model, nonequilibrium dense nuclear matter, pion pair production at finite temperature. (HSI)
On the spin saturation and thermal properties of nuclear matter
International Nuclear Information System (INIS)
The binding energy and the incompressibility of nuclear matter with degree of spin saturation D is calculated using the Skyrme interaction and two forms of a velocity dependent effective potential. The effect of the degree of spin saturation D on the thermal properties of nuclear matter is also discussed. It is found that generally the pressure decreases with increasing D. (author)
Anisotropic nuclear matter with momentum-dependent interaction
International Nuclear Information System (INIS)
A thermodynamically consistent nonthermal equation of state is presented for nuclear matter with momentum-dependent interactions in a state of anisotropic momentum distribution (expected in >2 GeV/nucleon beam energy heavy ion collisions). As an application the phase diagram for deconfinement transition of interpenetrating nuclear matter currents was constructed. (author)
On the thermal properties of nuclear matter with neutron excess
International Nuclear Information System (INIS)
The schematic model of nuclear matter proposed by Gomes, Walecka and Weisskopf which was generalized to finite temperatures including interacting Fermi particle aspects is extended here to include nuclear matter with neutron excess. The level density parameter as a function of neutron excess is calculated. Also the temperature dependence of the equilibrium Fermi momentum is calculated. (author)
On the thermal properties of polarized nuclear matter
International Nuclear Information System (INIS)
The thermal properties of polarized nuclear matter are calculated using Skyrme III interaction modified by Dabrowski for polarized nuclear matter. The temperature dependence of the volume, isospin, spin and spin isospin pressure and energies are determined. The temperature, isospin, spin and spin isospin dependence of the equilibrium Fermi momentum is also discussed. (author)
Studies for the equation of state in the isospin asymmetrical nuclear interactions
International Nuclear Information System (INIS)
In order to determine the equation of state in the isospin asymmetrical nuclear interactions, we have found the observables for extracting the information of them within the isospin-dependent quantum molecular dynamics in recent years. The several sensitive probes for extracting the information of the in-medium nucleon–nucleon cross section and the symmetry potential have found; meanwhile, their mechanisms are investigated in more details. The main point in this paper gives the summary for above probes and their outlook in the future. (author)
Heavy Vector and Axial-Vector Mesons in Hot and Dense Asymmetric Strange Hadronic Matter
Kumar, Arvind
2015-01-01
We calculate the effects of finite density and temperature of isospin asymmetric strange hadronic matter, for different strangeness fractions, on the in-medium properties of vector $\\left( D^{\\ast}, D_{s}^{\\ast}, B^{\\ast}, B_{s}^{\\ast}\\right)$ and axial-vector $\\left( D_{1}, D_{1s}, B_{1}, B_{1s}\\right)$ mesons, using chiral hadronic SU(3) model and QCD sum rules. We focus on the evaluation of in-medium mass-shift and shift in decay constant of above vector and axial-vector mesons. In QCD sum rule approach, the properties, e.g., the masses and decay constants of vector and axial-vector mesons are written in terms of quark and gluon condensates. These quark and gluon condensates are evaluated in the present work within chiral SU(3) model, through the medium modification of, scalar-isoscalar fields $\\sigma$ and $\\zeta$, the scalar-isovector field $\\delta$ and scalar dilaton field $\\chi$, in the strange hadronic medium which includes both nucleons as well as hyperons. As we shall see in detail, the masses and de...
Heavy Vector and Axial-Vector Mesons in Asymmetric Strange Hadronic Matter
Kumar, Arvind
2015-01-01
We calculate the effects of finite density of isospin asymmetric strange hadronic matter, for different strangeness fractions, on the in-medium properties of vector $\\left( D^{\\ast}, D_{s}^{\\ast}, B^{\\ast}, B_{s}^{\\ast}\\right)$ and axial-vector $\\left( D_{1}, D_{1s}, B_{1}, B_{1s}\\right)$ mesons using chiral hadronic SU(3) model and QCD sum rules. We focus on the evaluation of in-medium mass-shift and shift of decay constant of above vector and axial vector mesons. In QCD sum rule approach the properties e.g. masses and decay constants of vector and axial vector mesons are written in terms of quark and gluon condensates. These quarks and gluon condensates are evaluated in the present work using chiral SU(3) model through the medium modification of scalar-isoscalar fields $\\sigma$ and $\\zeta$, the scalar-isovector field $\\delta$ and scalar dilaton field $\\chi$ in strange hadronic medium which includes both nucleons as well as hyperons. As we shall see in detail the masses and decay constants of heavy vector an...
Energy Technology Data Exchange (ETDEWEB)
Typel, S.; Wolter, H.H. [Sektion Physik, Univ. Muenchen, Garching (Germany)
1998-06-01
Nuclear matter and ground state properties for (proton and neutron) semi-closed shell nuclei are described in relativistic mean field theory with coupling constants which depend on the vector density. The parametrization of the density dependence for {sigma}-, {omega}- and {rho}-mesons is obtained by fitting to properties of nuclear matter and some finite nuclei. The equation of state for symmetric and asymmetric nuclear matter is discussed. Finite nuclei are described in Hartree approximation, including a charge and an improved center-of-mass correction. Pairing is considered in the BCS approximation. Special attention is directed to the predictions for properties at the neutron and proton driplines, e.g. for separation energies, spin-orbit splittings and density distributions. (orig.)
Isospin Violating Dark Matter Search by Nuclear Emulsion Detector
Nagao, Keiko I.; Naka, Tatsuhiro
2012-01-01
Dark matter signal and its annual modulation of event number are observed by some direct searches in small mass region. However, the regions have been excluded by others. The isospin-violating dark matter is a hopeful candidate to explain the discrepancy. We study the possibility that a future project of dark matter search using nuclear emulsion can reach favored region by the isospin-violating dark matter. Since the detector has the directional sensitivity, it is expected t...
Relativistic Equation of State of Nuclear Matter for Supernova Explosion
Shen, H.; Toki, H.; Oyamatsu, K.; K. Sumiyoshi
1998-01-01
We construct the equation of state (EOS) of nuclear matter at finite temperature and density with various proton fractions within the relativistic mean field (RMF) theory for the use in the supernova simulations. The Thomas-Fermi approximation is adopted to describe the non-uniform matter where we consider nucleus, alpha-particle, proton and neutron in equilibrium. We treat the uniform matter and non-uniform matter consistently using the RMF theory. We tabulate the outcome a...
Antikaons in infinite nuclear matter and nuclei
Energy Technology Data Exchange (ETDEWEB)
Moeller, M.
2007-12-10
In this work we studied the properties of antikaons and hyperons in infinite cold nuclear matter. The in-medium antikaon-nucleon scattering amplitude and self-energy has been calculated within a covariant many-body framework in the first part. Nuclear saturation effects have been taken into account in terms of scalar and vector nucleon mean-fields. In the second part of the work we introduced a non-local method for the description of kaonic atoms. The many-body approach of anti KN scattering can be tested by the application to kaonic atoms. A self-consistent and covariant many-body approach has been used for the determination of the antikaon spectral function and anti KN scattering amplitudes. It considers s-, p- and d-waves and the application of an in-medium projector algebra accounts for proper mixing of partial waves in the medium. The on-shell reduction scheme is also implemented by means of the projector algebra. The Bethe-Salpeter equation has been rewritten, so that the free-space anti KN scattering can be used as the interaction kernel for the in-medium scattering equation. The latter free-space scattering is based on a realistic coupled-channel dynamics and chiral SU(3) Lagrangian. Our many-body approach is generalized for the presence of large scalar and vector nucleon mean-fields. It is supplemented by an improved renormalization scheme, that systematically avoids the occurrence of medium-induced power-divergent structures and kinematical singularities. A modified projector basis has been introduced, that allows for a convenient inclusion of nucleon mean-fields. The description of the results in terms of the 'physical' basis is done with the help of a recoupling scheme based on the projector algebra properties. (orig.)
Antikaons in infinite nuclear matter and nuclei
International Nuclear Information System (INIS)
In this work we studied the properties of antikaons and hyperons in infinite cold nuclear matter. The in-medium antikaon-nucleon scattering amplitude and self-energy has been calculated within a covariant many-body framework in the first part. Nuclear saturation effects have been taken into account in terms of scalar and vector nucleon mean-fields. In the second part of the work we introduced a non-local method for the description of kaonic atoms. The many-body approach of anti KN scattering can be tested by the application to kaonic atoms. A self-consistent and covariant many-body approach has been used for the determination of the antikaon spectral function and anti KN scattering amplitudes. It considers s-, p- and d-waves and the application of an in-medium projector algebra accounts for proper mixing of partial waves in the medium. The on-shell reduction scheme is also implemented by means of the projector algebra. The Bethe-Salpeter equation has been rewritten, so that the free-space anti KN scattering can be used as the interaction kernel for the in-medium scattering equation. The latter free-space scattering is based on a realistic coupled-channel dynamics and chiral SU(3) Lagrangian. Our many-body approach is generalized for the presence of large scalar and vector nucleon mean-fields. It is supplemented by an improved renormalization scheme, that systematically avoids the occurrence of medium-induced power-divergent structures and kinematical singularities. A modified projector basis has been introduced, that allows for a convenient inclusion of nucleon mean-fields. The description of the results in terms of the 'physical' basis is done with the help of a recoupling scheme based on the projector algebra properties. (orig.)
Dark Matter Particle Spectroscopy at the LHC: Generalizing M(T2) to Asymmetric Event Topologies
Energy Technology Data Exchange (ETDEWEB)
Konar, Partha; /Florida U.; Kong, Kyoungchul; /SLAC; Matchev, Konstantin T.; Park, Myeonghun; /Florida U.
2012-04-03
We consider SUSY-like missing energy events at hadron colliders and critically examine the common assumption that the missing energy is the result of two identical missing particles. In order to experimentally test this hypothesis, we generalize the subsystem M{sub T2} variable to the case of asymmetric event topologies, where the two SUSY decay chains terminate in different 'children' particles. In this more general approach, the endpoint M{sub T2(max)} of the M{sub T2} distribution now gives the mass {tilde M}p({tilde M}{sub c}{sup (a)}, {tilde M}{sub c}{sup (b)}) of the parent particles as a function of two input children masses {tilde M}{sub c}{sup (a)} and {tilde M}{sub c}{sup (b)}. We propose two methods for an independent determination of the individual children masses M{sub c}{sup (a)} and M{sub c}{sup (b)}. First, in the presence of upstream transverse momentum PUTM the corresponding function {tilde M}p({tilde M}{sub c}{sup (a)}, {tilde M}{sub c}{sup (b)}, P{sub UTM}) is independent of P{sub UTM} at precisely the right values of the children masses. Second, the previously discussed MT2 'kink' is now generalized to a 'ridge' on the 2-dimensional surface {tilde M}p({tilde M}{sub c}{sup (a)}, {tilde M}{sub c}{sup (b)}). As we show in several examples, quite often there is a special point along that ridge which marks the true values of the children masses. Our results allow collider experiments to probe a multi-component dark matter sector directly and without any theoretical prejudice.
Self-interacting asymmetric dark matter coupled to a light massive dark photon
International Nuclear Information System (INIS)
Dark matter (DM) with sizeable self-interactions mediated by a light species offers a compelling explanation of the observed galactic substructure; furthermore, the direct coupling between DM and a light particle contributes to the DM annihilation in the early universe. If the DM abundance is due to a dark particle-antiparticle asymmetry, the DM annihilation cross-section can be arbitrarily large, and the coupling of DM to the light species can be significant. We consider the case of asymmetric DM interacting via a light (but not necessarily massless) Abelian gauge vector boson, a dark photon. In the massless dark photon limit, gauge invariance mandates that DM be multicomponent, consisting of positive and negative dark ions of different species which partially bind in neutral dark atoms. We argue that a similar conclusion holds for light dark photons; in particular, we establish that the multi-component and atomic character of DM persists in much of the parameter space where the dark photon is sufficiently light to mediate sizeable DM self-interactions. We discuss the cosmological sequence of events in this scenario, including the dark asymmetry generation, the freeze-out of annihilations, the dark recombination and the phase transition which gives mass to the dark photon. We estimate the effect of self-interactions in DM haloes, taking into account this cosmological history. We place constraints based on the observed ellipticity of large haloes, and identify the regimes where DM self-scattering can affect the dynamics of smaller haloes, bringing theory in better agreement with observations. Moreover, we estimate the cosmological abundance of dark photons in various regimes, and derive pertinent bounds
Self-interacting asymmetric dark matter coupled to a light massive dark photon
Energy Technology Data Exchange (ETDEWEB)
Petraki, Kalliopi [Nikhef, Science Park 105, 1098 XG Amsterdam (Netherlands); Pearce, Lauren; Kusenko, Alexander, E-mail: kpetraki@nikhef.nl, E-mail: lpearce@ucla.edu, E-mail: kusenko@ucla.edu [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095-1547 (United States)
2014-07-01
Dark matter (DM) with sizeable self-interactions mediated by a light species offers a compelling explanation of the observed galactic substructure; furthermore, the direct coupling between DM and a light particle contributes to the DM annihilation in the early universe. If the DM abundance is due to a dark particle-antiparticle asymmetry, the DM annihilation cross-section can be arbitrarily large, and the coupling of DM to the light species can be significant. We consider the case of asymmetric DM interacting via a light (but not necessarily massless) Abelian gauge vector boson, a dark photon. In the massless dark photon limit, gauge invariance mandates that DM be multicomponent, consisting of positive and negative dark ions of different species which partially bind in neutral dark atoms. We argue that a similar conclusion holds for light dark photons; in particular, we establish that the multi-component and atomic character of DM persists in much of the parameter space where the dark photon is sufficiently light to mediate sizeable DM self-interactions. We discuss the cosmological sequence of events in this scenario, including the dark asymmetry generation, the freeze-out of annihilations, the dark recombination and the phase transition which gives mass to the dark photon. We estimate the effect of self-interactions in DM haloes, taking into account this cosmological history. We place constraints based on the observed ellipticity of large haloes, and identify the regimes where DM self-scattering can affect the dynamics of smaller haloes, bringing theory in better agreement with observations. Moreover, we estimate the cosmological abundance of dark photons in various regimes, and derive pertinent bounds.
Dielectron spectroscopy in cold nuclear matter
International Nuclear Information System (INIS)
The subject of this thesis is the production of light mesons and baryonic resonances in p+Nb collisions at Ekin=3.5 GeV via their decay in e+e- pairs and their kinematic observables. This reaction system in particular allows for the production of vector mesons in approximately cold nuclear matter and the study of expected in-medium effects. The experiment was conducted at the dielectron spectrometer HADES at GSI Helmholtzzentrum fuer Schwerionenforschung GmbH. In total, 64827±294 signal pairs with an pair opening angle ?ee>9 and e+/e- momenta 80e(MeV/c)ee(MeV/c2)ee> 550 MeV/c2). Inclusive e+e- production cross sections inside the HADES acceptance were calculated by analyzing the simultaneously measured charged pions and by comparing the obtained ?- yields to an independent data set. For the vector mesons one obtains ??,acc=(65.8±4.6(stat)±18.4(sys)) nb and ??,acc=(7.8±1.7(stat)±2.2 (sys)) nb. A comparison with cross sections in free p+p collisions at Ekin=3.5 GeV results in the nuclear modification factors RpA as well as their scaling ? with the nuclear mass number A and their dependence on the pair lab momenta pee. While absorption is not important for the ? meson (?? ?1), scaling factors ? ?0.7 are established for the quasi free decay (pee>800 MeV/c) of all other hadrons. From an adapted Glauber model calculation a minimal absorption >or similar 35% of all contributing hadrons in nuclei can be deduced. At smaller pair momenta different scaling factors are obtained. The ? meson is absorbed with a higher probability (??=0.62), but for all other sources above the ?0 mass, dominantly ?, ?, and ? with ?=0.82-0.86, production in secondary reactions exceeds the absorption inside the nucleus. Measured e+e- distributions were compared with different transport model calculations. Within the uncertainties the cross section of the ?0 Dalitz decay is reproduced in all models. However differences arise in the high mass region and the distributions of transverse momenta and rapidities. Additionally the GiBUU calculations describe the behaviour of slow and fast e+e- sources due to a momentum dependent in medium decay width. In the experiment no signal of the direct decay ??e+e- was measured. The existing upper level for the branching ratio BR=2.7 x 10-5 has to be reduced by at least a factor of 3. (orig.)
Kaons in nuclear matter; Kaonen in Kernmaterie
Energy Technology Data Exchange (ETDEWEB)
Kolomeitsev, E.E.
1997-02-01
The subject of the doctoral thesis is examination of the properties of kaons in nuclear matter. A specific method is explained that has been developed for the scientific objectives of the thesis and permits description of the kaon-nucleon interactions and kaon-nucleon scattering in a vacuum. The main challenge involved was to find approaches that would enable application of the derived relations out of the kaon mass shell, connected with the second objective, namely to possibly find methods which are independent of models. The way chosen to achieve this goal relied on application of reduction formulas as well as current algebra relations and the PCAC hypothesis. (orig./CB) [Deutsch] Die Arbeit befasst sich mit der Untersuchung der Eigenschaften von Kao nen in Kernmaterie. Zu diesem Zweck wurde ein Verfahren entwickelt, di e Kaon- Nukleon- Wechselwirkung und Kaon- Nukleon- Streuung im Vakuumzu beschreiben. Die Hauptherausforderung bestand darin, dass die abgel eiteten Relationen ausserhalb der Kaonen- Massenschale anwendbar werde n. Eine Nebenforderung war, dass die vorgeschlagenen Verfahren moeglic hst modell- unabhaengig sind. Um dieses Ziel zu erreichen, wurden Redu ktionsformeln, Stromalgebra- Relationen und die PCAC- Hypothese angewe ndet.
Condensed matter physics using nuclear resonant scattering
International Nuclear Information System (INIS)
Mössbauer spectroscopy is a powerful and well-established method used in a wide variety of scientific applications. An outstanding feature of this method is that element specific information on electronic and phonon states can be obtained. The use of high-brilliance synchrotron radiation as an excitation source for Mössbauer measurements enables measurements to be recorded under extreme conditions such as high pressures, very high or very low temperatures, and strong external magnetic fields. In addition, the tunability of synchrotron radiation energy allows a wide range of nuclides to be used. Moreover, the use of synchrotron radiation enables the measurement of the element- and site-specific phonon density of states. Another unique property of the method is the narrow energy width of the nuclear excited states, due to which the method is an effective tool for studying the slow dynamics of soft matter and glass transitions. The concepts and methods involved in these measurements are introduced and discussed, and the unique features of the methods are highlighted. (author)
Strangeness and Charm in Nuclear Matter
Tolos, Laura; Garcia-Recio, Carmen; Molina, Raquel; Nieves, Juan; Oset, Eulogio; Ramos, Angels; Romanets, Olena; Salcedo, Lorenzo Luis
2012-01-01
The properties of strange ($K$, $\\bar K$ and $\\bar K^*$) and open-charm ($D$, $\\bar D$ and $D^*$) mesons in dense matter are studied using a unitary approach in coupled channels for meson-baryon scattering. In the strangeness sector, the interaction with nucleons always comes through vector-meson exchange, which is evaluated by chiral and hidden gauge Lagrangians. For the interaction of charmed mesons with nucleons we extend the SU(3) Weinberg-Tomozawa Lagrangian to incorporate spin-flavor symmetry and implement a suitable flavor symmetry breaking. The in-medium solution for the scattering amplitude accounts for Pauli blocking effects and meson self-energies. On one hand, we obtain the $K$, $\\bar K$ and $\\bar K^*$ spectral functions in the nuclear medium and study their behaviour at finite density, temperature and momentum. We also make an estimate of the transparency ratio of the $\\gamma A \\to K^+ K^{*-} A^\\prime$ reaction, which we propose as a tool to detect in-medium modifications of the $\\bar K^*$ meson....
Skyrme-Hartree-Fock plus tensor correction for nuclear matter
International Nuclear Information System (INIS)
We study the equation of states of symmetric and pure neutron matter in the Skyrme-Hartree-Fock (SHF) model with tensor corrections. We are aware now that the pion exchange interaction has a significant contribution to nuclear structure in light nuclei. The pion generates a strong tensor interaction between two nucleons, which cannot be treated within the Hartree-Fock framework for the spin-saturated system such as homogeneous nuclear matter. Therefore, we study the role of the tensor interaction based on the SHF model, in which we extend it by explicitly introducing two-particle-two-hole (2p-2h) excitations for the treatment of the tensor interaction in symmetric nuclear matter and pure neutron matter. We are able to describe infinite matter very well using the SHF model with tensor corrections. We also discuss the connection between the symmetry energy and the tensor interaction in this framework. (author)
Skyrme-Hartree-Fock plus Tensor Correction for Nuclear Matter
Wang, Y.; Hu, J.; Toki, H.; Shen, H.
2012-04-01
We study the equation of states of symmetric and pure neutron matter in the Skyrme-Hartree-Fock (SHF) model with tensor corrections. We are aware now that the pion exchange interaction has a significant contribution to nuclear structure in light nuclei. The pion generates a strong tensor interaction between two nucleons, which cannot be treated within the Hartree-Fock framework for the spin-saturated system such as homogeneous nuclear matter. Therefore, we study the role of the tensor interaction based on the SHF model, in which we extend it by explicitly introducing two-particle-two-hole (2p-2h) excitations for the treatment of the tensor interaction in symmetric nuclear matter and pure neutron matter. We are able to describe infinite matter very well using the SHF model with tensor corrections. We also discuss the connection between the symmetry energy and the tensor interaction in this framework.
Reflection on penal policy in nuclear matters
International Nuclear Information System (INIS)
This document expresses ethical reflexions as far as nuclear energy development is concerned. The potential diversion of the peaceful use of nuclear energy results in the necessity of a criminal policy which would control the nuclear regulations. For each potential nuclear infringement, systems of laws are established either to prevent damages or to penalize them. (TEC)
K meson-nucleus interactions: strangeness and nuclear matter
International Nuclear Information System (INIS)
A brief review is provided of some straightforward K-nuclear and ?-hypernuclear systems. A discussion of less straightforward speculations on H-dibaryons and strange quark matter by many authors, is also given. 28 refs., 6 figs
A contribution to phenomenology of phase transitions in nuclear matter
International Nuclear Information System (INIS)
A review is given on the phenomenology of phase transitions in nuclear matter and neutron matter. We deal with (1) the liquid-gas transition in expanding nuclear systems and collapsing stellar cores, (2) the pion condensation in neutron stars and the direct pion emission in relativistic heavy ion collisions and (3) the deconfinement transition in neutron stars, in the early universe and in the compression/expansion stage of heavy ion reactions. (author)
Effects of Brown-Rho scalings in nuclear matter, neutron stars and finite nuclei
International Nuclear Information System (INIS)
We have carried out calculations for nuclear matter, neutron stars and finite nuclei using NN potentials with and without the medium-dependent modifications based on the Brown-Rho (BR) scalings. Using the Vlow-k low-momentum interactions derived from such potentials, the equations of state (EOS) for symmetric and asymmetric nuclear matter, for densities up to ? 5?0, are calculated using a RPA method where the particle-particle hole-hole ring diagrams are summed to all orders. The medium effects from both a linear BR scaling (BR1) and a non-linear one (BR2) are considered, and they both are essential for our EOSs to reproduce the nuclear matter saturation properties. For densities ? below ?0, results from BR1 and BR2 are close to each other. For higher densities, the EOS given by BR2 is more desirable and is well reproduced by that given by the interaction (Vlow-k+TBF) where Vlow-k is the unsealed low-momentum interaction and TBF is an empirical Skyrme three-body force. The moment of inertia of neutron stars is ? 60 and ? 25Mo-dotkm2 respectively with and without the inclusion of the above BR2 medium effects. Effects from the BR scaling are important for the long half-life, ? 5000yrs, of the 14C - 14N ?-decay.
Many-body theory of nuclear and neutron star matter
Energy Technology Data Exchange (ETDEWEB)
Pandharipande, V.R.; Akmal, A.; Ravenhall, D.G. [Dept. of Physics, Univ. of Illinois at Urbana-Champaign, Urbana, IL (United States)
1998-06-01
We present results obtained for nuclei, nuclear and neutron star matter, and neutron star structure obtained with the recent Argonne v{sub 18} two- nucleon and Urbana IX three-nucleon interactions including relativistic boost corrections. These interactions predict that matter will undergo a transition to a spin layered phase with neutral pion condensation. We also consider the possibility of a transition to quark matter. (orig.)
Many-body theory of nuclear and neutron star matter
International Nuclear Information System (INIS)
We present results obtained for nuclei, nuclear and neutron star matter, and neutron star structure obtained with the recent Argonne v18 two- nucleon and Urbana IX three-nucleon interactions including relativistic boost corrections. These interactions predict that matter will undergo a transition to a spin layered phase with neutral pion condensation. We also consider the possibility of a transition to quark matter. (orig.)
National control of nuclear matters. Protection against malicious intent
International Nuclear Information System (INIS)
This talk deals with, at first, the regulatory dispositions taken to guarantee the protection and the control of nuclear matters in installations and during transportation, and then with the general principles kept to evaluate the nuclear installations protection against malicious intent. (TEC)
The role of meson dynamics in nuclear matter saturation
International Nuclear Information System (INIS)
The problem of the saturation of nuclea matter in the non-relativistic limit of the model proposed by J.D. Walecka is studied. In the original context nuclear matter saturation is obtained as a direct consequence of relativistic effects and both scalar and vector mesons are treated statically. In the present work we investigate the effect of the meson dynamics for the saturation using a Born-Oppenheimer approximation for the ground state. An upper limit for the saturation curve of nuclear matter and are able to decide now essential is the relativistic treatment of the nucleons for this problem, is obtained. (author)
Saturation properties of nuclear matter with nonlocal confining solitons
International Nuclear Information System (INIS)
Saturation properties of a quark-based picture of nuclear matter are examined. Soliton matter consisting of nonlocal confining solitons is used to model nuclear matter. Each composite nucleon is described by a non-topological soliton as given by the Global Color Model. Techniques and concepts applied are known from the description of crystal lattices. In particular, the Wigner-Seitz approximation is used to calculate the properties of the soliton lattice at the mean-field level. The saturation density and incompressibility are calculated as function of the single input parameter of the model. (author)
Vacuum polarization effects on nuclear matter and neutron stars
International Nuclear Information System (INIS)
Vacuum renormalization of relativistic nuclear field theory is studied for nuclear and neutron star matter in general equilibrium, and neutron stars. It is found that when the coupling constants are tightly constrained by the five saturation properties of nuclear matter, the binding, density, compression modulus, symmetry energy and effective nucleon mass, the theory with or without vacuum renormalization predicts an equation of state that differs in the two cases by only several percent over the entire density range of interest. If the effective mass and compression are not controlled, as in some works, the high density behavior is markedly different. The mass of a neutron star, even at the limiting mass, is not dominated by the dense matter at its center, half the mass being contributed by matter at densities less than about 3?0. The hyperon fraction of the limiting mass star is about 20%. (orig.)
Reassessing nuclear matter incompressibility and its density dependence
De, J N; Agrawal, B K
2015-01-01
Experimental giant monopole resonance energies are now known to constrain nuclear incompressibility of symmetric nuclear matter $K$ and its density slope $M$ at a particular value of sub-saturation density, the crossing density $\\rho_c$. Consistent with these constraints, we propose a reasonable way to construct a plausible equation of state of symmetric nuclear matter in a broad density region around the saturation density $\\rho_0$. Help of two additional empirical inputs, the value of $\\rho_0$ and that of the energy per nucleon $e(\\rho_0)$ are needed. The value of $K(\\rho_0)$ comes out to be $211.9\\pm 24.5$ MeV.
The thermal curve of nuclear matter
International Nuclear Information System (INIS)
Earlier measurements of nuclear matter thermal curve of liquid to gas phase transition presented two limitation: only one temperature measuring method was available and the mass number of the formed nuclei decreased from 190 to 50 when the excitation energy increased. To avoid these limitations experiments with the multidetector INDRA at GANIL were carried-out. Among the quasi-projectiles issued from the 36Ar collisions at 52, 74, 95 A.MeV on the 58Ni, nuclei of close masses were selected. The excitation energy was determined by the calorimetry of the charged products emitted by quasi-projectiles while the temperature was measured by three different methods. Very different apparent temperatures were obtained for the same excitation energy/nucleon. Only one curve displays a slope variation but no indication of plateau. With the quasi-projectiles obtained from the collisions of 129Xe at 50 MeV/u on a 119Sn target behaviors similar to those of 36Ar were observed in the covered domain of excitation energy. To solve this puzzle and recover the initial temperatures of interest the only mean was to do a theoretical simulation in which one follows the de-excitation of the nuclei formed at different excitation energies and look for the thermal curve able to reproduce the observed temperatures. Two extreme possibilities were taken into account concerning the de-excitation process: either a sequential process established at E*/A? 3 MeV/u or a sudden multifragmentation in several hot fragments, most probably at E*/A? 10 MeV/u. In both cases it was possible to reproduce the whole set of experimental results concerning the 36Ar projectile. The initial temperature increases steadily as a function of excitation energy showing no plateau or singular points. The results indicate that, being a system without external pressure, in its passage from the liquid phase to the gas phase the nucleus does not display necessarily a temperature plateau. Discussions on interpretation of these results are under way
From quantum to semiclassical kinetic equations: Nuclear matter estimates
International Nuclear Information System (INIS)
Starting from the exact microscopic time evolution of the quantum one body density associated with a many fermion system semiclassical approximations are derived to it. In the limit where small momentum transfer two body collisions are dominant we get a Fokker-Planck equation and work out friction and diffusion tensors explicitly for nuclear matter. If arbitrary momentum transfers are considered a Boltzmann equation is derived and used to calculate the viscosity coefficient of nuclear matter. A derivation is given of the collision term used by Landau to describe the damping of zero sound waves at low temperature in Plasmas. Memory effects are essential for this. The damping of zero sound waves in nuclear matter is also calculated and the value so obtained associated with the bulk value of the damping of giant resonances in finite nuclei. The bulk value is estimated to be quite small indicating the importance of the nuclear surface for the damping. (Author)
From nuclear matter to finite nuclei. Pt. 1
International Nuclear Information System (INIS)
In this paper we develop various parametrizations of the nuclear matter Dirac-Brueckner G-matrix, which are suitable for application in relativistic Hartree-Fock calculations of finite nuclei. The relativistic one boson exchange model forms the basis of this effective interaction. The parameters, which are obtained from a least squares fit, explicitly depend on the density. We also require the interaction to reproduce the self-energies and the binding energy of nuclear matter very accurately. It is shown that for densities up to 1.5 times normal nuclear density the saturation curve virtually coincides with the original Dirac-Brueckner result and yields a good prediction of the nuclear matter compressibility. (orig.)
From holography towards real-world nuclear matter
Li, Si-wen; Wang, Qun
2015-01-01
Quantum chromodynamics is notoriously difficult to solve at nonzero baryon density, and most models or effective theories of dense quark or nuclear matter are restricted to a particular density regime and/or a particular form of matter. Here we study dense (and mostly cold) matter within the holographic Sakai-Sugimoto model, aiming at a strong-coupling framework in the wide density range between nuclear saturation density and ultra-high quark matter densities. The model contains only three parameters, and we ask whether it fulfills two basic requirements of real-world cold and dense matter, a first-order onset of nuclear matter and a chiral phase transition at high density to quark matter. Such a model would be extremely useful for astrophysical applications because it would provide a single equation of state for all densities relevant in a compact star. Our calculations are based on two approximations for baryonic matter, firstly an instanton gas and secondly a homogeneous ansatz for the non-abelian gauge fi...
From holography towards real-world nuclear matter
Li, Si-wen; Schmitt, Andreas; Wang, Qun
2015-07-01
Quantum chromodynamics is notoriously difficult to solve at nonzero baryon density, and most models or effective theories of dense quark or nuclear matter are restricted to a particular density regime and/or a particular form of matter. Here we study dense (and mostly cold) matter within the holographic Sakai-Sugimoto model, aiming at a strong-coupling framework in the wide density range between nuclear saturation density and ultrahigh quark matter densities. The model contains only three parameters, and we ask whether it fulfills two basic requirements of real-world cold and dense matter, a first-order onset of nuclear matter and a chiral phase transition at high density to quark matter. Such a model would be extremely useful for astrophysical applications because it would provide a single equation of state for all densities relevant in a compact star. Our calculations are based on two approximations for baryonic matter—first, an instanton gas and, second, a homogeneous ansatz for the non-Abelian gauge fields on the flavor branes of the model. While the instanton gas shows chiral restoration at high densities but an unrealistic second-order baryon onset, the homogeneous ansatz behaves exactly the other way around. Our study, thus, provides all ingredients that are necessary for a more realistic model and allows for systematic improvements of the applied approximations.
On the influence of the nuclear medium on the new nuclear matter states
International Nuclear Information System (INIS)
In many nucleus-nucleus collisions at high energies an increase of the particle production below the free nucleon-nucleon threshold has been observed. This increase can be related to the effects of the nuclear medium on the properties of the elementary particles, as well as on the new states of the nuclear matter, as resonance matter, for example. The present work takes into account the previous predictions on the rest mass particle modifications and resonance matter formation to discuss the influences of the nuclear medium on this new nuclear matter state. Experimental results on neutron-proton collisions at momenta between 1.25 GeV/c and 5.1 GeV/c, as well as on nucleus-nucleus collisions at energies between 1 A GeV and 15 A GeV are considered. Nuclear density and temperature determinations mainly at the pion emission, and the effective mass are used to establish the rest mass modification and the resonance weights in the considered collisions. A significant increase of the resonance matter formation is observed in nucleus-nucleus collisions, as compared with nucleon-nucleon collisions, at the same energy. The behaviour of the resonance matter formation in nucleus-nucleus collisions is also discussed. A like-saturation behaviour with energy increase can be considered. The major conclusion is that the nuclear medium has an important influence on the new states of nuclear matter. (authors)
Simulations of cold nuclear matter at sub-saturation densities
Energy Technology Data Exchange (ETDEWEB)
Giménez Molinelli, P.A., E-mail: pagm@df.uba.ar [Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and IFIBA, CONICET, Ciudad Universitaria, Buenos Aires 1428 (Argentina); Nichols, J.I. [Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and IFIBA, CONICET, Ciudad Universitaria, Buenos Aires 1428 (Argentina); López, J.A. [Department of Physics, University of Texas at El Paso, El Paso, TX 79968 (United States); Dorso, C.O. [Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and IFIBA, CONICET, Ciudad Universitaria, Buenos Aires 1428 (Argentina)
2014-03-01
Ideal nuclear matter is expected to undergo a first order phase transition at the thermodynamic limit. At such phase transitions the size of density fluctuations (bubbles or droplets) scale with the size of the system. This means that simulations of nuclear matter at sub-saturation densities will inexorably suffer from what is vaguely referred to as “finite size effects”. It is usually thought that these finite size effects can be diminished by imposing periodic boundary conditions and making the system large enough, but as we show in this work, that is actually not the case at sub-saturation densities. In this paper we analyze the equilibrium configurations of molecular dynamics simulations of a classical model for symmetric ideal (uncharged) nuclear matter at sub-saturation densities and low temperatures, where phase coexistence is expected at the thermodynamic limit. We show that the most stable configurations in this density range are almost completely determined by artificial aspects of the simulations (i.e. boundary conditions) and can be predicted analytically by surface minimization. This result is very general and is shown to hold true for several well known semi-classical models of nuclear interaction and even for a simple Lennard-Jones potential. Also, in the limit of very large systems, when “small size” effects can be neglected, those equilibrium configurations seem to be restricted to a few structures reminiscent to the “Pasta Phases” expected in Neutron Star matter, but arising from a completely different origin: In Neutron Star matter, the non-homogeneous structures arise from a competition between nuclear and Coulomb interactions while for ideal nuclear matter they emerge from finite (yet not “small”) size effects. The role of periodic boundary conditions and finite size effects in Neutron Star matter simulations are reexamined.
J/{Psi} mass shift in nuclear matter
Energy Technology Data Exchange (ETDEWEB)
Krein, G., E-mail: gkrein@ift.unesp.b [Instituto de Fisica Teorica, Universidade Estadual Paulista, Rua Dr. Bento Teobaldo Ferraz, 271-Bloco II, Sao Paulo, SP (Brazil); Thomas, A.W., E-mail: anthony.thomas@adelaide.edu.a [CSSM, School of Chemistry and Physics, University of Adelaide, Adelaide SA 5005 (Australia); Tsushima, K., E-mail: tsushima@jlab.or [EBAC in Theory Center, Jefferson Lab, 12000 Jefferson Ave. Newport News, VA 23606 (United States)
2011-02-28
The J/{Psi} mass shift in cold nuclear matter is computed using an effective Lagrangian approach. The mass shift is computed by evaluating D and D{sup *} meson loop contributions to the J/{Psi} self-energy employing medium-modified meson masses. The modification of the D and D{sup *} masses in nuclear matter is obtained using the quark-meson coupling model. The loop integrals are regularized with dipole form factors and the sensitivity of the results to the values of form-factor cutoff masses is investigated. The J/{Psi} mass shift arising from the modification of the D and D{sup *} loops at normal nuclear matter density is found to range from -16 MeV to -24 MeV under a wide variation of values of the cutoff masses. Experimental perspectives for the formation of a bound state of J/{Psi} to a nucleus are investigated.
Binding energy per nucleon and hadron properties in nuclear matter
Yakhshiev, Ulugbek
2010-01-01
We investigate the binding energy per nucleon and hadron properties in infinite and homogeneous nuclear matter within the framework of the in-medium modified Skyrme model. We first consider the medium modifications of the single hadron properties by introducing the optical potential for pion fields into the original Lagrangian of the Skyrme model. The parameters of the optical potential are well fitted to the low-energy phenomenology of pion-nucleus scattering. Furthermore, the Skyrme term is also modified in such a way that the model reproduces bulk properties of nuclear matter, in particular, the binding energy per nucleon. The present approach is self-consistent: the single hadron properties in a nuclear medium, their effective in-medium interactions, and the bulk matter properties are treated on the same footing.
Valid QCD sum rules for vector mesons in nuclear matter
International Nuclear Information System (INIS)
QCD sum rules for vector mesons (?, ?, ?) in nuclear matter are reexamined with an emphasis on the reliability of various sum rules. Monitoring the continuum contribution and the convergence of the operator product expansion plays a crucial role in determining the validity of a sum rule. The uncertainties arising from less than precise knowledge of the condensate values and other input parameters are analyzed via a Monte Carlo error analysis. Our analysis leaves no doubt that vector-meson masses decrease with increasing density. This resolves the current debate over the behavior of the vector-meson masses and the sum rules to be used in extracting vector meson properties in nuclear matter. We find a ratio of ?-meson masses of m?*/m?=0.78±0.08 at nuclear matter saturation density
Holographic cold nuclear matter as dilute instanton gas
Ghoroku, Kazuo; Tachibana, Motoi; Taminato, Tomoki; Toyoda, Fumihiko
2012-01-01
We study cold nuclear matter based on the holographic gauge theory, where baryons are introduced as the instantons in the probe D8/$\\bar{\\rm D8}$ branes according to the Sakai-Sugimoto model. Within a dilute gas approximation of instantons, we seek for the stable states via the variational method and fix the instanton size. We find the first order phase transition from the vacuum to the nuclear matter phase as we increase the chemical potential. At the critical chemical potential, we could see a jump of the baryon density from zero to a finite definite value. While the size of the baryon in the nuclear matter is rather small compared to the nucleus near the transition point, where the charge density is also small, it increases with the baryon density. Those behaviors obtained here are discussed by relating to the force between baryons.
The modification of the scalar field in dense nuclear matter
International Nuclear Information System (INIS)
We show the possible evolution of the nuclear deep inelastic structure function with nuclear density ?. The nucleon deep inelastic structure function represents distribution of quarks as a function of Bjorken variable x, which measures the longitudinal fraction of the momentum carried by them during deep inelastic scattering (DIS) of electrons on nuclear targets. The quark localization is proportional to 1/x and this relation introduces the dependence of the nucleon structure function on the nuclear medium. Starting with small density and negative pressure in nuclear matter (NM), we have relatively large inter-nucleon distances and increasing role of nuclear interaction mediated by virtual mesons. When the density approaches the saturation point, ? = ?0, we have no longer separate mesons and nucleons but eventually modified nucleon structure function (SF) in the medium. The ratio of the nuclear to the nucleon SF measured at the saturation point is well known as the "EMC effect". For larger density, ? > ?0, when the localization of quarks is smaller than 0.3 fm, the nucleons overlap. We argue that nucleon mass should start to decrease in order to satisfy the momentum sum rule (MSR) of DIS. These modifications of the nucleon structure function are calculated in the frame of the nuclear relativistic mean field (RMF) convolution model. The correction to the Fermi energy from a term proportional to the pressure is very important and its inclusion modifies the equation of state (EoS) for the nuclear matter. (author)
Binding energy per nucleon and hadron properties in nuclear matter
Yakhshiev, Ulugbek; Kim, Hyun-Chul
2011-03-01
We investigate the binding energy per nucleon and hadron properties in infinite and homogeneous nuclear matter within the framework of the in-medium modified Skyrme model. We first consider the medium modifications of the single hadron properties by introducing the optical potential for pion fields into the original Lagrangian of the Skyrme model. The parameters of the optical potential are well fitted to the low-energy phenomenology of pion-nucleus scattering. Furthermore, the Skyrme term is also modified in such a way that the model reproduces the bulk properties of nuclear matter, in particular, the binding energy per nucleon.
Energy-range relations for hadrons in nuclear matter
Strugalski, Z.
1985-01-01
Range-energy relations for hadrons in nuclear matter exist similarly to the range-energy relations for charged particles in materials. When hadrons of GeV kinetic energies collide with atomic nuclei massive enough, events occur in which incident hadron is stopped completely inside the target nucleus without causing particle production - without pion production in particular. The stoppings are always accompanied by intensive emission of nucleons with kinetic energy from about 20 up to about 400 MeV. It was shown experimentally that the mean number of the emitted nucleons is a measure of the mean path in nuclear matter in nucleons on which the incident hadrons are stopped.
Quarkyonic percolation in dense nuclear matter
Lottini, Stefano; Torrieri, Giorgio
2012-01-01
We examine the phase diagram of hadronic matter when the number of colours $N_c$, as well as temperature and density, are varied. We show that in this regime a new percolation phase transition is possible, and examine the implications of this transition for extrapolations to physical QCD of the large-N_c limit.
Pion absorption in excited nuclear matter
International Nuclear Information System (INIS)
The target dependence and azimuthal correlations of protons and plons are investigated for pA reactions at 4.9, 60 and 200 GeV. The experimental observations can be understood qualitatively under the assumption that pions are absorbed in excited target spectator matter. (orig.)
Neutron-Proton Mass Difference in Nuclear Matter and in Finite Nuclei and the Nolen-Schiffer Anomaly
Meißner, U.-G.; Rakhimov, A. M.; Wirzba, A.; Yakhshiev, U. T.
2010-04-01
The neutron-proton mass difference in (isospin asymmetric) nuclear matter and finite nuclei is studied in the framework of a medium-modified Skyrme model. The proposed effective Lagrangian incorporates both the medium influence of the surrounding nuclear environment on the single nucleon properties and an explicit isospin-breaking effect in the mesonic sector. Energy-dependent charged and neutral pion optical potentials in the s- and p-wave channels are included as well. The present approach predicts that the neutron-proton mass difference is mainly dictated by its strong part and that it markedly decreases in neutron matter. Furthermore, the possible interplay between the effective nucleon mass in finite nuclei and the Nolen-Schiffer anomaly is discussed. In particular, we find that a correct description of the properties of mirror nuclei leads to a stringent restriction of possible modifications of the nucleon's effective mass in nuclei.
Neutron-Proton Mass Difference in Nuclear Matter and in Finite Nuclei and the Nolen-Schiffer Anomaly
Meißner, Ulf-G; Wirzba, A; Yakhshiev, U T
2009-01-01
The neutron-proton mass difference in (isospin asymmetric) nuclear matter and finite nuclei is studied in the framework of a medium-modified Skyrme model. The proposed effective Lagrangian incorporates both the medium influence of the surrounding nuclear environment on the single nucleon properties and an explicit isospin-breaking effect in the mesonic sector. Energy-dependent charged and neutral pion optical potentials in the s- and p-wave channels are included as well. The present approach predicts that the neutron-proton mass difference is mainly dictated by its strong part and that it markedly decreases in neutron matter. Furthermore, the possible interplay between the effective nucleon mass in finite nuclei and the Nolen-Schiffer anomaly is discussed. In particular, we find that a correct description of the properties of mirror nuclei leads to a stringent restriction of possible modifications of the nucleon's effective mass in nuclei.
Converting of Matter to Nuclear Energy by AB-Generator
Alexander Bolonkin
2009-01-01
Problem statement: Researcher offered a new nuclear generator which allowed to convert any matter to nuclear energy in accordance with Einstein equation E = mc2. The method was based upon tapping the energy potential of a Micro Black Hole (MBH) and Hawking radiation created by this MBH. Researcher did not meet the idea and its research in literature to develop the method for getting a cheap energy. Approach: As is well-known, vacuum continuously produced virtual pairs of particles and antipar...
Exponential enhancement of nuclear reactions in condensed matter environment
Kuchiev, M. Yu.; Altshuler, B.L.; Flambaum., V. V.
2003-01-01
A mechanism that uses the environment to enhance the probability of the nuclear reaction when a beam of accelerated nuclei collides with a target nucleus implanted in condensed matter is suggested. The effect considered is exponentially large for low collision energies. For t + p collision the mechanism becomes effective when the energy of the projectile tritium is below $\\sim$ 1 Kev per nucleon. The gain in probability of the nuclear reaction is due to a redistribution of e...
Energy Technology Data Exchange (ETDEWEB)
Margueron, J
2001-07-01
We study the elementary interactions between neutrinos and dense matter in a proto-neutron star. Equations of state obtained with different nuclear effective interactions (Skyrme, Gogny, Relativistic Lagrangians) are first discussed. Then, we characterize their stability in spin and isospin. We derive magnetic susceptibilities for all isospin asymmetry values as a function of Landau parameters G{sup {pi}}{sup {pi}}{sup '}{sub 0} (where {pi}, {pi}' = proton or neutron). From this work, we select a parametrization for each of the 3 effective forces: Sly230b,D1P,NL3. We calculate the pure neutron matter and asymmetric nuclear matter response functions with and without charge exchange, describing nuclear correlations in both approaches: non-relativistic (Hartree-Fock with Skyrme forces, then complete RPA) and relativistic (in the Hartree approximation). At the end, we calculate neutrino mean free paths neutral current and charged current reactions. Comparisons between relativistic and non-relativistic approaches allow us to identify relativistic effects in nuclear matter at densities as low as twice the saturation density. RPA correlations make the medium more transparent to neutrinos compared to free Fermi gas. The importance of the effective mass in mean free path calculations is also shown. (author)
International Nuclear Information System (INIS)
The properties of nuclear matter and nuclear scattering reactions were studied from the same effective nucleon-nucleon interactions. In this project, we used CDM3Y and M3Y-Pn interaction version as the input to build the nuclear interaction potential (nuclear optical potential). After that, nuclear scattering reactions were studied by coupled channel formalism and folding model for scattering potential. The theoretical calculated cross sections of (alpha, nucleus) and (nucleon, nucleus) scattering system have been compared with the experimental values. Using the above interactions, the properties of nuclear matter: (i) biding energy, (ii) pressure and (iii) Compressibility were deduced in the Hartree-Fock calculation frame work. From the consistence between theory and experiment, the information of nuclear structure has been extracted. (author)
The Modification of the Scalar Field in dense Nuclear Matter
Directory of Open Access Journals (Sweden)
Ro?ynek J.
2011-04-01
Full Text Available We show the possible evolution of the nuclear deep inelastic structure function with nuclear density ?. The nucleon deep inelastic structure function represents distribution of quarks as function of Björken variable x which measures the longitudinal fraction of momentum carried by them during the Deep Inelastic Scattering (DIS of electrons on nuclear targets. Starting with small density and negative pressure in Nuclear Matter (NM we have relatively large inter-nucleon distances and increasing role of nuclear interaction mediated by virtual mesons.When the density approaches the saturation point, ? = ?0, we have no longer separate mesons and nucleons but eventually modified nucleon Structure Function (SF in medium. The ratio of nuclear to nucleon SF measured at saturation point is well known as “EMC effect”. For larger density, ? > ?0, when the localization of quarks is smaller then 0.3 fm, the nucleons overlap. We argue that nucleon mass should start to decrease in order to satisfy the Momentum Sum Rule (MSR of DIS. These modifications of the nucleon Structure Function (SF are calculated in the frame of the nuclear Relativistic Mean Field (RMF convolution model. The correction to the Fermi energy from term proportional to the pressure is very important and its inclusion modifies the Equation of State (EoS for nuclear matter.
Nuclear forces and nuclear matter including pions and isobars
International Nuclear Information System (INIS)
Conventional nuclear theory is based on the rather successful model which stipulates that nuclei consist of nucleons with two-body interactions. Extensive use of pion beams as probes of nuclear structure suggests a minimal extension of this model to include pion degrees of freedom explicitly in a manner which allows production and absorption of pions without dressing isolated nucleons with a pion cloud. Some properties of such models are the subject of this talk. (orig./HSI)
Fluctuations in quantum transport theories of nuclear matter
International Nuclear Information System (INIS)
The formulation of quantum kinetic equations is based on the real-time Green's function formalism. Introducing semi-classical approximations one obtains the so-called Kadanoff-Baym equations. These equations are used as a starting point for studying the occurrence of quantum fluctuations and their relevance for transport phenomena in nuclear matter. (orig.)
Fluctuations in quantum transport theories of nuclear matter
Energy Technology Data Exchange (ETDEWEB)
Malfliet, R. (Kernfysisch Versneller Inst., Groningen (Netherlands))
1992-08-03
The formulation of quantum kinetic equations is based on the real-time Green's function formalism. Introducing semi-classical approximations one obtains the so-called Kadanoff-Baym equations. These equations are used as a starting point for studying the occurrence of quantum fluctuations and their relevance for transport phenomena in nuclear matter. (orig.).
Matter in extremis: Ultrarelativistic nuclear collisions at RHIC
International Nuclear Information System (INIS)
We review the physics of nuclear matter at high energy density and the experimental search for the Quark-Gluon Plasma at the Relativistic Heavy Ion Collider (RHIC). The data obtained in the first three years of the RHIC physics program provide several lines of evidence that a novel state of matter has been created in the most violent, head-on collisions of Au nuclei at ?s = 200 GeV. Jet quenching and global measurements show that the initial energy density of the strongly interacting medium generated in the collision is about two orders of magnitude larger than that of cold nuclear matter, well above the critical density for the deconfinement phase transition predicted by lattice QCD. The observed collective flow patterns imply that the system thermalizes early in its evolution, with the dynamics of its expansion consistent with ideal hydrodynamic flow based on a Quark-Gluon Plasma equation of state
Relativistic Mean-Field Models and Nuclear Matter Constraints
Dutra, M; Carlson, B V; Delfino, A; Menezes, D P; Avancini, S S; Stone, J R; Providência, C; Typel, S
2013-01-01
This work presents a preliminary study of 147 relativistic mean-field (RMF) hadronic models used in the literature, regarding their behavior in the nuclear matter regime. We analyze here different kinds of such models, namely: (i) linear models, (ii) nonlinear \\sigma^3+\\sigma^4 models, (iii) \\sigma^3+\\sigma^4+\\omega^4 models, (iv) models containing mixing terms in the fields \\sigma and \\omega, (v) density dependent models, and (vi) point-coupling ones. In the finite range models, the attractive (repulsive) interaction is described in the Lagrangian density by the \\sigma (\\omega) field. The isospin dependence of the interaction is modeled by the \\rho meson field. We submit these sets of RMF models to eleven macroscopic (experimental and empirical) constraints, used in a recent study in which 240 Skyrme parametrizations were analyzed. Such constraints cover a wide range of properties related to symmetric nuclear matter (SNM), pure neutron matter (PNM), and both SNM and PNM.
Matter in extremis: Ultrarelativistic nuclear collisions at RHIC
Energy Technology Data Exchange (ETDEWEB)
Jacobs, Peter; Wang, Xin-Nian
2004-08-20
We review the physics of nuclear matter at high energy density and the experimental search for the Quark-Gluon Plasma at the Relativistic Heavy Ion Collider (RHIC). The data obtained in the first three years of the RHIC physics program provide several lines of evidence that a novel state of matter has been created in the most violent, head-on collisions of Au nuclei at {radical}s = 200 GeV. Jet quenching and global measurements show that the initial energy density of the strongly interacting medium generated in the collision is about two orders of magnitude larger than that of cold nuclear matter, well above the critical density for the deconfinement phase transition predicted by lattice QCD. The observed collective flow patterns imply that the system thermalizes early in its evolution, with the dynamics of its expansion consistent with ideal hydrodynamic flow based on a Quark-Gluon Plasma equation of state.
Nuclear matter from effective quark-quark interaction.
Baldo, M; Fukukawa, K
2014-12-12
We study neutron matter and symmetric nuclear matter with the quark-meson model for the two-nucleon interaction. The Bethe-Bruckner-Goldstone many-body theory is used to describe the correlations up to the three hole-line approximation with no extra parameters. At variance with other nonrelativistic realistic interactions, the three hole-line contribution turns out to be non-negligible and to have a substantial saturation effect. The saturation point of nuclear matter, the compressibility, the symmetry energy, and its slope are within the phenomenological constraints. Since the interaction also reproduces fairly well the properties of the three-nucleon system, these results indicate that the explicit introduction of the quark degrees of freedom within the considered constituent quark model is expected to reduce the role of three-body forces. PMID:25541769
Formation of hot, dense matter in fast nuclear collisions
International Nuclear Information System (INIS)
High energy (Esub(LAB) >> 10 MeV/u) heavy ion collisions are investigated in a nuclear fluid dynamical model. We discuss the influence of the properties of the nuclear equation of state at high densities and strong thermal excitation on the reaction dynamics. We predict that sideways emission of matter will occur and that nuclear residues will obtain large transverse momenta. For collisions of equal nuclei at small impact parameters we expect four jet events, due to 'bounce-off' fragments, and the explosion of the remaining, highly excited matter perpendicular to the scattering plane. For the collision of a small projectile with a heavy target the flow of Mach-shock-matter at a characteristic angle to the beam direction is predicted. At intermediate impact parameters the possibility of using the bounce-off effect to study the nuclear equation of state is investigated. We present recent experimental data (mostly obtained in 4? counters) which support the prediction of high compression phenomena. These experiments were performed by selecting events of high multiplicity of low and intermediate energy fragments, which indicate nearly central collisions. He-fragments and also protons are observed, which, following their angular and energy spectra, can not be attributed to evaporative emission from a source moving along the reaction axis. Finally we discuss the formation of quark matter at very high energies. In this process rapid oscillations of the expanding dense quark matter may lead to pulsed emission of matter. These oscillating quark blobs may explain the abnormally enhanced geometrical cross sections observed recently in secondary collisions of projectile fragments with target nuclei. (author)
Climate Change, Nuclear Power and Nuclear Proliferation: Magnitude Matters
International Nuclear Information System (INIS)
Integrated energy, environment and economics modeling suggests electrical energy use will increase from 2.4 TWe today to 12 TWe in 2100. It will be challenging to provide 40% of this electrical power from combustion with carbon sequestration, as it will be challenging to provide 30% from renewable energy sources. Thus nuclear power may be needed to provide ?30% by 2100. Calculations of the associated stocks and flows of uranium, plutonium and minor actinides indicate that the proliferation risks at mid-century, using current light-water reactor technology, are daunting. There are institutional arrangements that may be able to provide an acceptable level of risk mitigation, but they will be difficult to implement. If a transition is begun to fast-spectrum reactors at mid-century, without a dramatic change in the proliferation risks of such systems, at the end of the century proliferation risks are much greater, and more resistant to mitigation. The risks of nuclear power should be compared with the risks of the estimated 0.64 C long-term global surface-average temperature rise predicted if nuclear power were replaced with coal-fired power plants without carbon sequestration. Fusion energy, if developed, would provide a source of nuclear power with much lower proliferation risks than fission.
Climate Change, Nuclear Power and Nuclear Proliferation: Magnitude Matters
Energy Technology Data Exchange (ETDEWEB)
Robert J. Goldston
2010-03-03
Integrated energy, environment and economics modeling suggests electrical energy use will increase from 2.4 TWe today to 12 TWe in 2100. It will be challenging to provide 40% of this electrical power from combustion with carbon sequestration, as it will be challenging to provide 30% from renewable energy sources. Thus nuclear power may be needed to provide ~30% by 2100. Calculations of the associated stocks and flows of uranium, plutonium and minor actinides indicate that the proliferation risks at mid-century, using current light-water reactor technology, are daunting. There are institutional arrangements that may be able to provide an acceptable level of risk mitigation, but they will be difficult to implement. If a transition is begun to fast-spectrum reactors at mid-century, without a dramatic change in the proliferation risks of such systems, at the end of the century proliferation risks are much greater, and more resistant to mitigation. The risks of nuclear power should be compared with the risks of the estimated 0.64oC long-term global surface-average temperature rise predicted if nuclear power were replaced with coal-fired power plants without carbon sequestration. Fusion energy, if developed, would provide a source of nuclear power with much lower proliferation risks than fission.
Climate Change, Nuclear Power and Nuclear Proliferation: Magnitude Matters
International Nuclear Information System (INIS)
Integrated energy, environment and economics modeling suggests that worldwide electrical energy use will increase from 2.4 TWe today to ?12 TWe in 2100. It will be challenging to provide 40% of this electrical power from combustion with carbon sequestration, as it will be challenging to provide 30% from renewable energy sources derived from natural energy flows. Thus nuclear power may be needed to provide ?30%, 3600 GWe, by 2100. Calculations of the associated stocks and flows of uranium, plutonium and minor actinides indicate that the proliferation risks at mid-century, using current light-water reactor technology, are daunting. There are institutional arrangements that may be able to provide an acceptable level of risk mitigation, but they will be difficult to implement. If a transition is begun to fast-spectrum reactors at mid-century, without a dramatic change in the proliferation risks of such systems, at the end of the century global nuclear proliferation risks are much greater, and more resistant to mitigation. Fusion energy, if successfully demonstrated to be economically competitive, would provide a source of nuclear power with much lower proliferation risks than fission.
Climate Change, Nuclear Power and Nuclear Proliferation: Magnitude Matters
Energy Technology Data Exchange (ETDEWEB)
Robert J. Goldston
2011-04-28
Integrated energy, environment and economics modeling suggests that worldwide electrical energy use will increase from 2.4 TWe today to ~12 TWe in 2100. It will be challenging to provide 40% of this electrical power from combustion with carbon sequestration, as it will be challenging to provide 30% from renewable energy sources derived from natural energy flows. Thus nuclear power may be needed to provide ~30%, 3600 GWe, by 2100. Calculations of the associated stocks and flows of uranium, plutonium and minor actinides indicate that the proliferation risks at mid-century, using current light-water reactor technology, are daunting. There are institutional arrangements that may be able to provide an acceptable level of risk mitigation, but they will be difficult to implement. If a transition is begun to fast-spectrum reactors at mid-century, without a dramatic change in the proliferation risks of such systems, at the end of the century global nuclear proliferation risks are much greater, and more resistant to mitigation. Fusion energy, if successfully demonstrated to be economically competitive, would provide a source of nuclear power with much lower proliferation risks than fission.
Enhancement of nuclear reactions in matter
International Nuclear Information System (INIS)
Full text: We analyze enhancement of the nuclear fusion initiated by low-energy projectile deuterons, though we do not aim at interpreting particular experiments reported previously. The nuclear fusion processes at low energies are exponentially suppressed due to the Coulomb repulsion. We consider several factors which can enhance the fusion. The most powerful among them is the 'carambole' mechanism of enhancement. It needs that a projectile deuteron and a target deuteron undergo a chain of preliminary elastic collisions between themselves and nuclei of Environment. These collisions effectively convert the fixed-target process into a fusion reaction with colliding beams. This reduces the exponent of the factor that describes penetration through the Coulomb barrier by a factor 21/2, thus drastically, by many orders of magnitude (1011,) increasing the probability. We also calculate increase of the fusion probability given by two other mechanisms by the motion of a bound target deuteron in a solid and by stimulation of this motion by the Coulomb field of a projectile. The later effect we call the 'ping-pong' mechanism. The factor which gives increase for the fusion probability for the three considered mechanisms is illustrated. For low energies the 'carambole' mechanism dominates, producing very strong effect. We expect it to be most efficient in compounds with target deuterons localized in the vicinity of heavy atoms. The electric fields in non-equilibrium processes (like chemical reactions, where cracks in solids or cavities in liquids) or in ferroelectric materials may accelerate deuterons creating the beam-like situation. The beam-like problem may also arise in laser-induced fusion where ions are accelerated due to the laser field and the interaction with electrons
Nuclear matter descriptions including quark structure of the hadrons
International Nuclear Information System (INIS)
It is nowadays well established that nucleons are composite objects made of quarks and gluons, whose interactions are described by Quantum chromodynamics (QCD). However, because of the non-perturbative character of QCD at the energies of nuclear physics, a description of atomic nuclei starting from quarks and gluons is still not available. A possible alternative is to construct effective field theories based on hadronic degrees of freedom, in which the interaction is constrained by QCD. In this framework, we have constructed descriptions of infinite nuclear matter in relativistic mean field theories taking into account the quark structure of hadrons. In a first approach, the in medium modifications of mesons properties is dynamically obtained in a Nambu-Jona-Lasinio (NJL) quark model. This modification is taken into account in a relativistic mean field theory based on a meson exchange interaction between nucleons. The in-medium modification of mesons masses and the properties of infinite nuclear matter have been studied. In a second approach, the long and short range contributions to the in-medium modification of the nucleon are determined. The short range part is obtained in a NJL quark model of the nucleon. The long range part, related to pions exchanges between nucleons, has been determined in the framework of Chiral Perturbation theory. These modifications have been used to constrain the couplings of a point coupling relativistic mean field model. A realistic description of the saturation properties of nuclear matter is obtained. (author)
The ?? cloud contribution to the ? width in nuclear matter
Energy Technology Data Exchange (ETDEWEB)
Cabrera, D. [Institute for Theoretical Physics, Frankfurt University, 60438 Frankfurt am Main (Germany); Frankfurt Institute for Advanced Studies, Frankfurt University, 60438 Frankfurt am Main (Germany); Rapp, R. [Cyclotron Institute and Department of Physics and Astronomy, Texas A and M University, College Station, TX 77843-3366 (United States)
2014-02-05
The width of the ? meson in cold nuclear matter is computed in a hadronic many-body approach, focusing on a detailed treatment of the medium modifications of intermediate ?? states. The ? and ? propagators are dressed by their self-energies in nuclear matter taken from previously constrained many-body calculations. The pion self-energy includes Nh and ?h excitations with short-range correlations, while the ? self-energy incorporates the same dressing of its 2? cloud with a full 3-momentum dependence and vertex corrections, as well as direct resonance-hole excitations; both contributions were quantitatively fit to total photo-absorption spectra and ?N??N scattering. Our calculations account for in-medium decays of type ?N??N{sup (?)},??N(?), and 2-body absorptions ?NN?NN{sup (?)},?NN. This causes deviations of the in-medium ? width from a linear behavior in density, with important contributions from spacelike ? propagators. The ? width from the ?? cloud may reach up to 200 MeV at normal nuclear matter density, with a moderate 3-momentum dependence. This largely resolves the discrepancy of linear T–? approximations with the values deduced from nuclear photoproduction measurements.
Pairing in bulk nuclear matter beyond BCS
Energy Technology Data Exchange (ETDEWEB)
Ding, D.; Dickhoff, W. H.; Dussan, H. [Department of Physics, Washington University, St. Louis, Missouri 63130 (United States); Witte, S. J. [Department of Physics, Washington University, St. Louis, Missouri 63130, USA and Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 (United States); Rios, A. [Department of Physics, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom); Polls, A. [Departament d' Estructura i Constituents de la Matèria, Universitat de Barcelona, E-08028 Barcelona (Spain)
2014-10-15
The influence of short-range correlations on the spectral distribution of neutrons is incorporated in the solution of the gap equation for the {sup 3}P{sub 2}?{sup 3}F{sub 2} coupled channel in pure neutron matter. This effect is studied for different realistic interactions including one based on chiral perturbation theory. The gap in this channel vanishes at all relevant densities due to the treatment of these correlations. We also consider the effect of long-range correlations by including polarization terms in addition to the bare interaction which allow the neutrons to exchange density and spin fluctuations governed by the strength of Landau parameters allowed to have reasonable values consistent with the available literature. Preliminary results indicate that reasonable values of these parameters do not generate a gap in the {sup 3}P{sub 2}?{sup 3}F{sub 2} coupled channel either for all three realistic interactions although the pairing interaction becomes slightly more attractive.
Relativistic mean-field hadronic models under nuclear matter constraints
Dutra, M.; Lourenço, O.; Avancini, S. S.; Carlson, B. V.; Delfino, A.; Menezes, D. P.; Providência, C.; Typel, S.; Stone, J. R.
2014-11-01
Background: The microscopic composition and properties of infinite hadronic matter at a wide range of densities and temperatures have been subjects of intense investigation for decades. The equation of state (EoS) relating pressure, energy density, and temperature at a given particle number density is essential for modeling compact astrophysical objects such as neutron stars, core-collapse supernovae, and related phenomena, including the creation of chemical elements in the universe. The EoS depends not only on the particles present in the matter, but, more importantly, also on the forces acting among them. Because a realistic and quantitative description of infinite hadronic matter and nuclei from first principles in not available at present, a large variety of phenomenological models has been developed in the past several decades, but the scarcity of experimental and observational data does not allow a unique determination of the adjustable parameters. Purpose: It is essential for further development of the field to determine the most realistic parameter sets and to use them consistently. Recently, a set of constraints on properties of nuclear matter was formed and the performance of 240 nonrelativistic Skyrme parametrizations was assessed [M. Dutra et al., Phys. Rev. C 85, 035201 (2012), 10.1103/PhysRevC.85.035201] in describing nuclear matter up to about three times nuclear saturation density. In the present work we examine 263 relativistic-mean-field (RMF) models in a comparable approach. These models have been widely used because of several important aspects not always present in nonrelativistic models, such as intrinsic Lorentz covariance, automatic inclusion of spin, appropriate saturation mechanism for nuclear matter, causality, and, therefore, no problems related to superluminal speed of sound in medium. Method: Three different sets of constraints related to symmetric nuclear matter, pure neutron matter, symmetry energy, and its derivatives were used. The first set (SET1) was the same as used in assessing the Skyrme parametrizations. The second and third sets (SET2a and SET2b) were more suitable for analysis of RMF and included, up-to-date theoretical, experimental and empirical information. Results: The sets of updated constraints (SET2a and SET2b) differed somewhat in the level of restriction but still yielded only 4 and 3 approved RMF models, respectively. A similarly small number of approved Skyrme parametrizations were found in the previous study with Skyrme models. An interesting feature of our analysis has been that the results change dramatically if the constraint on the volume part of the isospin incompressibility (K? ,v) is eliminated. In this case, we have 35 approved models in SET2a and 30 in SET2b. Conclusions: Our work provides a new insight into application of RMF models to properties of nuclear matter and brings into focus their problematic proliferation. The assessment performed in this work should be used in future applications of RMF models. Moreover, the most extensive set of refined constraints (including nuclear matter and finite-nuclei-related properties) should be used in future determinations of new parameter sets to provide models that can be used with more confidence in a wide range of applications. Pointing to reasons for the many failures, even of the frequently used models, should lead to their improvement and to the identification of possible missing physics not included in present energy density functionals.
Phase transitions in high excited nuclear matter
International Nuclear Information System (INIS)
This work is a study of the mechanism of thermal multifragmentation, which takes place in collisions of light relativistic projectiles with heavy targets. This is a new multibody decay process of very hot nuclei (target spectator) with emission of a number of intermediate mass fragments (IMF, 2 4He and 12C with Au. The main results are the following: - The mean IMF multiplicity () saturates at 2.2 ± 0.2.This fact cannot be rendered by the traditional approach with the intranuclear cascade (INC) followed by Statistical Multifragmentation Models (SMM). Considering the expansion phase between two parts of the calculations, the excitation energies and the residual masses are empirically modified to obtain agreement with the measured IMF- multiplicities. The mean excitation energy is found to be around 500 MeV for the beam energies above 5 GeV. This modified model is denoted as INC + ? + SMM where ? indicates the preequilibrium processes. - The expansion is driven by the thermal pressure. It is larger for 4He and 12C induced collisions because of higher initial temperature. The kinetic energy spectra of IMF become harder and the expansion flow is visible. The total flow energy of the system is estimated to be around 115 MeV both for the He and the carbon beams. - The analysis of the data reveals very interesting information on the fragment space distribution inside the break-up volume. Heavier IMF are formed predominately in the interior of the fragmenting nucleus possibly due to a density gradient. This conclusion is in contrast to the predictions of the Statistical Multifragmentation Model (SMM). - This study of the multifragmentation using a range of projectiles demonstrates a transition from pure '' thermal decay '' (for p + Au collisions) to disintegration '' completed by '' the onset of a collective flow for the heavier projectiles. Nevertheless, in case of reaction caused by fast protons the decay mechanism should be considered as a thermal multifragmentation. - The time scale of the thermal multifragmentation in p + Au collision at 8.1 GeV has been measured for the first time (by the analysis of IMF-IMF angular correlations). The mean decay time of the fragmenting system was found to be ? = (50 ± 18) fm/c in accordance with the scenario of a '' simultaneous '' multibody decay of a hot and expanded nuclear system. The measured time-scale is close to that for the density fluctuation in the diluted nuclear system. Hence, the thermal multifragmentation can be interpreted as the first order nuclear liquid-fog phase transition in the spinodal region. - Characteristic temperature Tf is less than Tc - critical temperature for the liquid-gas phase transition. Tc -critical temperature for the liquid-gas phase transition is found to be (17 ± 2) MeV, which is significantly larger than the temperature of fragmenting system (5 - 6 MeV). This is a very important observation in favour of the mechanism of spinodal disintegration. - It is concluded that the decay process of hot nuclei is characterized by two size parameters: transition state and freeze-out volumes. The IMF emission time is related to the mean rupture time at the multi-scission point, which corresponds to the kinetic freeze-out configuration. (author)
Open charm tomography of cold nuclear matter
Vitev, I; Johnson, M B; Qiu, J W
2006-01-01
We study the relative contribution of partonic sub-processes to D meson production and D meson-triggered inclusive di-hadrons to lowest order in perturbative QCD. While gluon fusion dominates the creation of large angle DD-bar pairs, charm on light parton scattering determines the yield of single inclusive D mesons. The distinctly different non-perturbative fragmentation of c quarks into D mesons versus the fragmentation of quarks and gluons into light hadrons results in a strong transverse momentum dependence of anticharm content of the away-side charm-triggered jet. In p+A reactions, we calculate and resum the coherent nuclear-enhanced power corrections from the final state partonic scattering in the medium. We find that single and double inclusive open charm production can be suppressed as much as the yield of neutral pions from dynamical high-twist shadowing. Effects of energy loss in p+A collisions are also investigated phenomenologically and may lead to significantly weaker transverse momentum dependenc...
Mondal, C; De, J N
2015-01-01
Elements of nuclear symmetry energy evaluated from different energy density functionals parametrized by fitting selective bulk properties of few representative nuclei are seen to vary widely. Those obtained from experimental data on nuclear masses across the periodic table, however, show that they are better constrained. A possible direction in reconciling this paradox may be gleaned from comparison of results obtained from use of the binding energies in the fitting protocol within a microscopic model with two sets of nuclei, one a representative standard set and another where very highly asymmetric nuclei are additionally included. A covariance analysis reveals that the additional fitting protocol reduces the uncertainties in the nuclear symmetry energy coefficient, its slope parameter as well as the neutron-skin thickness in $^{208}$Pb nucleus by $\\sim 50\\%$. The central values of these entities are also seen to be slightly reduced.
Mondal, C.; Agrawal, B. K.; De, J. N.
2015-08-01
Elements of nuclear symmetry energy evaluated from different energy density functionals parametrized by fitting selective bulk properties of few representative nuclei are seen to vary widely. Those obtained from experimental data on nuclear masses across the periodic table, however, show that they are better constrained. A possible direction in reconciling this paradox may be gleaned from comparison of results obtained from use of the binding energies in the fitting protocol within a microscopic model with two sets of nuclei, one a representative standard set and another where very highly asymmetric nuclei are additionally included. A covariance analysis reveals that the additional fitting protocol reduces the uncertainties in the nuclear symmetry energy coefficient, its slope parameter, as well as the neutron-skin thickness in 208Pb nucleus by ˜50 % . The central values of these entities are also seen to be slightly reduced.
Three-body properties in hot and dense nuclear matter
Beyer, M; Kuhrts, C; Röpke, G
1999-01-01
We derive three-body equations valid at finite densities and temperatures. These are based on the cluster mean field approach consistently including proper self energy corrections and the Pauli blocking. As an application we investigate the binding energies of triton and determine the Mott densities and momenta relevant for a many particle description of nuclear matter in a generalized Beth-Uhlenbeck approach. The method, however is not restricted to nuclear physics problems but may also be relevant, e.g., to treat three-particle correlations in weekly doped semiconducters or strongly coupled dense plasmas.
Two-particle properties in nuclear matter at finite temperatures
Röpke, G
1999-01-01
Correlation effects in nuclear matter at finite temperatures are studied for subnuclear densities ($\\rho<\\rho_0$) and medium excitation energy, where a nonrelativistic potential approach is possible. A quantum statistical approach is given, where clusters are treated under the influence of a clustered medium treated within a mean field approximation. Spectral functions, in-medium cross sections, and reaction rates are considered as well as the formation of a quantum condensate. In particluar, exploratory calculations are shown with respect to the pseudo gap in the nucleon level density close to the superfluid phase transition. Estimates of isospin singlet pairing and quartetting in nuclear binding energies are given.
Light clusters in nuclear matter of finite temperature
Beyer, M; Schuck, P; Sofianos, S A
2003-01-01
We investigate properties and the distribution of light nuclei (A<4) in symmetric nuclear matter of finite temperature within a microscopic framework. For this purpose we have solved few-body Alt-Grassberger-Sandhas type equations for quasi-nucleons that include self-energy corrections and Pauli blocking in a systematic way. In a statistical model we find a significant influence in the composition of nuclear matter if medium effects are included in the microscopic calculation of nuclei. If multiplicities are frozen out at a certain time (or volume), we expect significant consequences for the formation of light fragments in a heavy ion collision. As a consequence of the systematic inclusion of medium effects the ordering of multiplicities becomes opposite to the law of mass action of ideal components. This is necessary to explain the large abundance of $\\alpha$-particles in a heavy ion collision that are otherwise largely suppressed in an ideal equilibrium scenario.
From nuclear matter to finite nuclei. Pt. 2
International Nuclear Information System (INIS)
We discuss various relativistic models describing ground-state properties of spherical nuclei, are discussed. Relativistic mean-field and Hartree-Fock theories, which serve as a startingpoint for subsequent models, are reviewed. Using a density-dependent parametrization of the Dirac-Brueckner G-matrix in nuclear matter, we achieve an effective Dirac-Brueckner-Hartree-Fock model for finite nuclei. Finite nuclei results obtained with this model are compared with the less advanced Density-Dependent Mean-Field model, which simulates Dirac-Brueckner calculations for nuclear matter as well. It is shown that the effective Dirac-Brueckner-Hartree-Fock approach most successfully reproduces experimental data concerning spherical nuclei. (orig.)
Relativistic nuclear matter with alternative derivative coupling models
International Nuclear Information System (INIS)
Effective Lagrangians involving nucleons coupled to scalar and vector fields are investigated within the framework of relativistic mean-field theory. The study presents the traditional Walecka model and different kinds of scalar derivative couplings suggested by Zimanyi and Moszkowski. The incompressibility (presented in an analytical form), scalar potential, and vector potential at the saturation point of nuclear matter are compared for these models. The real optical potential for the models are calculated and one of the models fits well the experimental curve from -50 to 400 MeV while also giving a soft equation of state. By varying the coupling constants and keeping the saturation point of nuclear matter approximately fixed, only the Walecka model presents a first order phase transition for finite temperature at zero density
Strangeness in nuclear matter at DA{Phi}NE
Energy Technology Data Exchange (ETDEWEB)
Gianotti, P. [INFN, Laboratori Nazionali di Frascati, Rome (Italy)
1998-01-01
The low energy kaons from the {phi} meson produced at DA{Phi}NE offer a unique opportunity to study strangeness in nuclear matter. The interaction of kaons with hadronic matter can be investigated at DA{Phi}NE using three main approaches: study of hypernuclei production and decay, kaons scattering on nucleons, kaonic atoms formation. These studies explore kaon-nucleon and hyperon-nucleon forces at very low energy, the nuclear shell model in presence of strangeness quantum number and eventual quarks deconfinement phenomena. The experiments devoted to study this physical program at DA{Phi}NE are FINUDA and DEAR. The physics topics of both experiments are illustrated together with a detailed descriptions of the two detectors.
Strangeness in nuclear matter at DA?NE
International Nuclear Information System (INIS)
The low energy kaons from the ? meson produced at DA?NE offer a unique opportunity to study strangeness in nuclear matter. The interaction of kaons with hadronic matter can be investigated at DA?NE using three main approaches: study of hypernuclei production and decay, kaons scattering on nucleons, kaonic atoms formation. These studies explore kaon-nucleon and hyperon-nucleon forces at very low energy, the nuclear shell model in presence of strangeness quantum number and eventual quarks deconfinement phenomena. The experiments devoted to study this physical program at DA?NE are FINUDA and DEAR. The physics topics of both experiments are illustrated together with a detailed descriptions of the two detectors
The Coester line in relativistic mean field nuclear matter
Scientific Electronic Library Online (English)
A., Delfino; M., Malheiro; V. S., Timóteo; J. S. Sá, Martins.
2005-03-01
Full Text Available The Walecka model contains essentially two parameters that are associated with the Lorentz scalar (S) and vector (V) interactions. These parameters are related to a two-body interaction consisting of S and V, imposing the condition that the two-body binding energy is fixed. We have obtained a set of [...] different values for the nuclear matter binding energies (B N) at equilibrium densities (rhoo). We investigated the existence of a linear correlation between B N and rhoo, claimed to be universal for nonrelativistic systems and usually known as the Coester line, and found an approximate linear correlation only if V - S remains constant. It is shown that the relativistic content of the model, which is related to the strength of V - S, is responsible for the shift of the Coester line to the empirical region of nuclear matter saturation.
Determination of nuclear-matter temperature and density
International Nuclear Information System (INIS)
Some of the things learned about nuclear matter under extreme conditions during the past few years in relativistic heavy ion studies are reviewed. Two developments are discussed. The completion of analyses and publication of results from the impact parameter selected, single-particle inclusive experiments have proven to be important. Preliminary results from the new generation of two-particle correlation and particle-exclusive measurements, especially those using streamer chambers, look even more definitive. Also the measurement of more exotic ejectiles with long mean free paths in nuclear matter promises to provide more basic information. Calculations are offering real guidance and are providing explanations of high energy collisions. The Monte Carlo and intranuclear cascade calculations discussed are especially informative
A quark-meson model for nuclear and neutron matter
Saito, K; Thomas, A.W.(ARC Centre of Excellence for Particle Physics at the Terascale and CSSM, School of Chemistry and Physics, The University of Adelaide, Australia)
1994-01-01
An explicit quark model, based on a mean field description of non-overlapping nucleon bags bound by the self-consistent exchange of $\\sigma$, $\\omega$ and $\\rho$ mesons, is used to investigate the properties of both nuclear and neutron matter. We establish a clear understanding of the relationship between this model, which incorporates the internal structure of the nucleon, and QHD. Finally, we use the model to study the density dependence of the quark condensate in-medium.
Three- and four-body correlations in nuclear matter
International Nuclear Information System (INIS)
Few-nucleon correlations in nuclear matter at finite densities and temperatures are explored. Using the Dyson-equation approach leads to effective few-body equations that include self-energy corrections and Pauli blocking factors in a systematic way. Examples given are the nucleon-deuteron in-medium reaction rates, few-body bound states including the ?-particle, and ?-particle condensation. Refs. 17 (author)
Three- and Four-body correlations in nuclear matter
Beyer, M
2002-01-01
Few-nucleon correlations in nuclear matter at finite densities and temperatures are explored. Using the Dyson equation approach leads to effective few-body equations that include self energy corrections and Pauli blocking factors in a systematic way. Examples given are the nucleon deuteron in-medium reaction rates, few-body bound states including the $\\ga$-particle, and $\\ga$-particle condensation.
Detector developing for directional dark matter search with nuclear emulsion
International Nuclear Information System (INIS)
We are planing the directional dark matter search experiment with nuclear emulsion. Recoiled atoms inside of the emulsion fly several hundred nm, and it is too short to detect with usual emulsion. Fine crystal emulsion was needed to detect such tracks. We developed new method to produce them and succeeded to make crystals small as 20 nm at the minimum size. We also study several methods to improve sensitivity and reduce background noise to survey very interesting cross section region
Investigation of the organic matter in inactive nuclear tank liquids
International Nuclear Information System (INIS)
Environmental Protection Agency (EPA) methodology for regulatory organics fails to account for the organic matter that is suggested by total organic carbon (TOC) analysis in the Oak Ridge National Laboratory (ORNL) inactive nuclear waste-tank liquids and sludges. Identification and measurement of the total organics are needed to select appropriate waste treatment technologies. An initial investigation was made of the nature of the organics in several waste-tank liquids. This report details the analysis of ORNL wastes
Equation of state of quark-nuclear matter
Krein, G.; Vizcarra, V. E.
2002-01-01
Quark-nuclear matter (QNM) is a many-body system containing hadrons and deconfined quarks. Starting from a microscopic quark-meson coupling (QMC) Hamiltonian with a density dependent quark-quark interaction, an effective quark-hadron Hamiltonian is constructed via a mapping procedure. The mapping is implemented with a unitary operator such that composites are redescribed by elementary-particle field operators that satisfy canonical commutation relations in an extended Fock s...
Binding energy per nucleon and hadron properties in nuclear matter
Yakhshiev, Ulugbek; Kim, Hyun-CHul
2010-01-01
We investigate the binding energy per nucleon and hadron properties in infinite and homogeneous nuclear matter within the framework of the in-medium modified Skyrme model. We first consider the medium modifications of the single hadron properties by introducing the optical potential for pion fields into the original Lagrangian of the Skyrme model. The parameters of the optical potential are well fitted to the low-energy phenomenology of pion-nucleus scattering. Furthermore, ...
Skyrme interaction to second order in nuclear matter
Kaiser, N
2015-01-01
Based on the phenomenological Skyrme interaction various density-dependent nuclear matter quantities are calculated up to second order in many-body perturbation theory. The spin-orbit term as well as two tensor terms contribute at second order to the energy per particle. The simultaneous calculation of the isotropic Fermi-liquid parameters provides a rigorous check through the validity of the Landau relations. It is found that published results for these second order contrib...
Competition of ferromagnetic and antiferromagnetic spin ordering in nuclear matter
Isayev, A. A.
2003-01-01
In the framework of a Fermi liquid theory it is considered the possibility of ferromagnetic and antiferromagnetic phase transitions in symmetric nuclear matter with Skyrme effective interaction. The zero temperature dependence of ferromagnetic and antiferromagnetic spin polarization parameters as functions of density is found for SkM$^*$, SGII effective forces. It is shown that in the density domain, where both type of solutions of self--consistent equations exist, ferromagn...
The 2-neutrino double beta decay in nuclear matter
International Nuclear Information System (INIS)
We analyze the suppression mechanism of the (2-neutrino? ?) amplitudes, in the framework of superfluid nuclear matter. We show that the interplay between spin-isospin modes and spin pairing vibrations in quenching the ? ? amplitude is particularly transparent in the context of the polarization propagator method and quite efficient in suppressing the decay width. Our procedure is applied to finite nuclei of interest and the results compared to other theoretical evaluations and to the experimental data
Mean field effects in hot compressed nuclear matter
Molitoris, Molitoris, Joseph J.; Bonasera, A; Winer, Brian L.; Stöcker, Horst (Prof. Dr.)
2006-01-01
We study effects of the mean field in hot compressed nuclear matter in the context of the Vlasov Uehling-Uhlenbeck theory. The expansion of a spherical distribution at different temperatures is studied along with collisions of Nb+Nb and Au+Au at lab energies from 50 to 1050 MeV/nucleon. In both the expansion and the actual heavy ion collision simulation, a transition behavior is seen only at the lowest temperature (T
Cold Nuclear Matter Effects and Heavy Quark Production in PHENIX
International Nuclear Information System (INIS)
The PHENIX experiment uses semileptonic and leptonic decay channels, respectively, to measure open and closed heavy flavor cross sections across the rapidity range ?2.2NN)=200GeV, and for Au + Au collisions at ?(SNN)=62GeV. We discuss recent d + Au results for open heavy flavor and J/? production, and discuss their implications for the cold nuclear matter contributions to heavy flavor production in heavy ion collisions
Mixed phase of QCD matter in relativistic nuclear collisions
International Nuclear Information System (INIS)
Aim of the report is to discuss possibilities of formation and experimental investigation of the matter QCD mixed phase in relativistic nuclear collisions at 1 GeV/nucleonlablab/A=(3-7) GeV/nucleon. Instability of collision impact compression mode production of quark clusters with high strangeness and strong fluctuations of the observed properties of secondary hadrons in separate events may serve as specific signals of its formation. 21 refs.; 4 figs
Directory of Open Access Journals (Sweden)
Wolniak Stephen M
2011-10-01
Full Text Available Abstract Background Many rapidly developing systems rely on the regulated translation of stored transcripts for the formation of new proteins essential for morphogenesis. The microspores of the water fern Marsilea vestita dehydrate as they mature. During this process both mRNA and proteins required for subsequent development are stored within the microspores as they become fully desiccated and enter into senescence. At this point microspores become transcriptionally silent and remain so upon rehydration and for the remainder of spermatogenesis. Transcriptional silencing coupled with the translation of preformed RNA makes the microspore of M. vestita a useful system in which to study post-transcriptional regulation of RNA. Results We have characterized the distribution of mRNA as well as several conserved markers of subnuclear bodies within the nuclei of desiccating spores. During this period, nuclear speckles containing RNA were seen to aggregate forming a single large coalescence. We found that aggregated speckles contain several masked mRNA species known to be essential for spermatogenesis. During spermatogenesis masked mRNA and associated speckle proteins were shown to fragment and asymmetrically localize to spermatogenous but not sterile cells. This asymmetric localization was disrupted by RNAi knockdown of the Marsilea homolog of the Exon Junction Complex core component Mago nashi. Conclusions A subset of masked mRNA is stored in association with nuclear speckles during the dormant phase of microspore development in M. vestita. The asymmetric distribution of specific mRNAs to spermatogenous but not sterile cells mirrors their translational activities and appears to require the EJC or EJC components. This suggests a novel role for nuclear speckles in the post-transcriptional regulation of transcripts.
Coexisting single particle solutions in low density symmetric nuclear matter
International Nuclear Information System (INIS)
The only two nucleon bound state system occurring in free space is the deuteron, constituted by a proton neutron pair. Although the neutron neutron interaction is attractive, its strength is not deep enough to allow for a bound state in the form of a dineutron. However, this picture changes drastically when the interacting neutrons are submerged in nuclear matter. In this contribution we address di nucleon properties as implied by the Brueckner Hartree Fock approximation for infinite symmetric nuclear matter at zero temperature.Special emphasis is given to di nucleon formation in the search of self-consistent single-particle fields, leading to novel features for low-density nuclear matter, i.e. mass densities of the order of 1011-12 g cm-3. Searches have been carried out at Fermi momenta in the range 0 < k F 1.75 fm-1 using the Argonne vt8 bare nucleon-nucleon potential. As a result, two distinct solutions meeting self-consistency are found with overlapping domains in the interval 0.130 fm-1 k F 0.285 fm-1. Effective masses as high as three times the nucleon mass are found in the coexistence domain, in resemblance to heavy Fermions in strongly correlated systems. Properties of di nucleon bound state solutions and possible implications shall be discussed
Infinite nuclear matter based for mass of atomic nuclei
International Nuclear Information System (INIS)
The ground-state energy of an atomic nucleus with asymmetry ? is considered to be equivalent to the energy of a perfect sphere made up of infinite nuclear matter of the same asymmetry plus a residual energy eta, called the local energy. Eta represents the energy due to shell, deformation, diffuseness and exchange Coulomb effects, etc. Using this picture and the generalised Hugenholtz-Van Hove theorem of many-body theory, the previously proposed mass relation is derived in a transport way in which eta drops away in a very natural manner. The validity of this mass relation is studied globally using the latest mass table. The model is suitable for the extraction of the saturation properties of nuclear matter. The binding energy per nucleon and the saturation Fermi momentum of nuclear matter obtained through this model are 18.33 MeV and 1.48 fm-1 respectively. It is shown in several representative cases in the Periodic Table that the masses of nuclei in the far unknown region can be reliably predicted. (author)
Skyrme interaction to second order in nuclear matter
Kaiser, N.
2015-09-01
Based on the phenomenological Skyrme interaction various density-dependent nuclear matter quantities are calculated up to second order in many-body perturbation theory. The spin–orbit term as well as two tensor terms contribute at second order to the energy per particle. The simultaneous calculation of the isotropic Fermi-liquid parameters provides a rigorous check through the validity of the Landau relations. It is found that published results for these second order contributions are incorrect in most cases. In particular, interference terms between s-wave and p-wave components of the interaction can contribute only to (isospin or spin) asymmetry energies. Even with nine adjustable parameters, one does not obtain a good description of the empirical nuclear matter saturation curve in the low density region 0\\lt ? \\lt 2{? }0. The reason for this feature is the too strong density-dependence {? }8/3 of several second-order contributions. The inclusion of the density-dependent term \\frac{1}{6}{t}3{? }1/6 is therefore indispensable for a realistic description of nuclear matter in the Skyrme framework.
Finite size effects in neutron star and nuclear matter simulations
International Nuclear Information System (INIS)
In this work we study molecular dynamics simulations of symmetric nuclear and neutron star matter using a semi-classical nucleon interaction model. Our aim is to gain insight on the nature of the so-called “finite size effects”, unavoidable in this kind of simulations, and to understand what they actually affect. To do so, we explore different geometries for the periodic boundary conditions imposed on the simulation cell: cube, hexagonal prism and truncated octahedron. For nuclear matter simulations we show that, at sub-saturation densities and low temperatures, the solutions are non-homogeneous structures reminiscent of the “nuclear pasta” phases expected in neutron star matter simulations, but only one structure per cell and shaped by specific artificial aspects of the simulations—for the same physical conditions (i.e. number density and temperature) different cells yield different solutions. The particular shape of the solution at low enough temperature and a given density can be predicted analytically by surface minimization. We also show that even if this behavior is due to the imposition of periodic boundary conditions on finite systems, this does not mean that it vanishes for very large systems, and it is actually independent of the system size. We conclude that, for nuclear matter simulations, the cells' size sets the only characteristic length scale for the inhomogeneities, and the geometry of the periodic cell determines the shape of those inhomogeneities. To model neutron star matter we add a screened Coulomb interaction between protons, and perform simulations in the three cell geometries. Our simulations indeed produce the well known nuclear pasta, with (in most cases) several structures per cell. However, we find that for systems not too large results are affected by finite size in different ways depending on the geometry of the cell. In particular, at the same certain physical conditions and system size, the hexagonal prism yields a single structure per cell while the cubic and truncated octahedron show consistent results, with more than one structure per cell. For systems of the size studied in this work these effects are still noticeable, but we find evidence to support that the dependence of the results on the cell geometry becomes smaller as the system size is increased. When the Coulomb interaction is present, the competition between opposing interactions of different range results in a proper, physically meaningful length scale that is independent of the system size and periodic cell of choice. Only under these conditions “finite size effects” will vanish for large enough systems (i.e. cells much larger than this characteristic length). Larger simulations are in order, but our computational capabilities forbid it for the time being
Nuclear spin resonances in double beta decays and dark matters
International Nuclear Information System (INIS)
In this paper, as the experiment using the spin in atomic nuclei as the experimental means, the double data decay and the experiment for searching for dark matters by Ejiri group of Osaka University are reported. Double beta decay is the phenomenon in which beta decay occurs twice successively in atomic nuclei, and theoretically a number of decay modes are considered. In double beta decay, two beta rays (electrons) and two neutrinos are emitted, therefore, the energy spectra of beta ray become continuous. The probability of decay, the effect of neutrino emission and others are discussed. The detector (ELEGANTS V) that the group of Osaka University uses for the measurement is introduced. The thin film specimens of Mo are used. The spectrum is shown, and the half life was obtained. The results are reported. The existence of space dark matters was predicted, but it has not been found. The application of NaI detector to the search for dark matters has been investigated. NaI consists of the nuclei having finite nuclear spin, and is suitable to the search for the dark matters of spin coupling type. The limit for the existence of dark matters was determined. (K.I.)
Lectures on Effective Field Theories for Nuclei, Nuclear Matter and Dense Matter
Rho, Mannque
2002-01-01
This note is based on four lectures that I gave at the 10th Taiwan Nuclear Spring School held at Hualien, Taiwan in January 2002. It aims to correlate the old notion of Cheshire Cat Principle developed for elementary baryons to the modern notion of quark-baryon and gluon-meson "continuities" or "dualities" in dilute and dense many-body systems and predict what would happen to mesons when squeezed by nuclear matter to high density as possibly realized in compact stars. Using ...
International Nuclear Information System (INIS)
Thermodynamically self-consistent class of nuclear matter equations of state are considered. For two different equations of state with deconfinement phase transition the compression shock adiabats are calculated. The shock stability for mixed phase formation is studied. 17 refs.; 4 figs
Application of effective field theory on nuclear matter and neutron matter
International Nuclear Information System (INIS)
In the thesis the effective field theory in NLO and NNLO order is applied. The order NLO still knows no three-particle forces. The theory yields however already in this order the saturation behaviour of nuclear matter. This is due to the fact that in the NLO order the scattering phases are qualitatively correctly reproduced, especially the scattering phases 1S0 and 3S1 are for energies above 200 MeV negative, which is in all potentials by a so called hard core represented. In the NNLO orde three-particle forces occur, which lead to a larger improvement of the saturation curve, however the saturation point lies still at too high densities. A correction of the low-energy constants by scarcely three percent of the value in the vacuum generates however a saturation curve, which reproduces the empirical binding energy per particle, the density and the compressibility of nuclear matter. About the equation of state of neutron matter is empirically few known. At small densities of neutron matter (kf-1) the NLO and NNLO orders scarcely differ, but indeed from the free Fermi gas. For applications in finite nuclei a simplified parametrization of the nucleon-nucleon interactions was developed, which reproduces both the known scattering phases with an NLO-comparable accuracy and the empirical saturation behaviour
Relativistic mean-field models and nuclear matter constraints
Energy Technology Data Exchange (ETDEWEB)
Dutra, M.; Lourenco, O.; Carlson, B. V. [Departamento de Fisica, Instituto Tecnologico de Aeronautica-CTA, 12228-900, Sao Jose dos Campos, SP (Brazil); Delfino, A. [Instituto de Fisica, Universidade Federal Fluminense, 24210-150, Boa Viagem, Niteroi, RJ (Brazil); Menezes, D. P.; Avancini, S. S. [Departamento de Fisica, CFM, Universidade Federal de Santa Catarina, CP. 476, CEP 88.040-900, Florianopolis, SC (Brazil); Stone, J. R. [Oxford Physics, University of Oxford, OX1 3PU Oxford (United Kingdom) and Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996 (United States); Providencia, C. [Centro de Fisica Computacional, Department of Physics, University of Coimbra, P-3004-516 Coimbra (Portugal); Typel, S. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Theorie, Planckstrasse 1,D-64291 Darmstadt (Germany)
2013-05-06
This work presents a preliminary study of 147 relativistic mean-field (RMF) hadronic models used in the literature, regarding their behavior in the nuclear matter regime. We analyze here different kinds of such models, namely: (i) linear models, (ii) nonlinear {sigma}{sup 3}+{sigma}{sup 4} models, (iii) {sigma}{sup 3}+{sigma}{sup 4}+{omega}{sup 4} models, (iv) models containing mixing terms in the fields {sigma} and {omega}, (v) density dependent models, and (vi) point-coupling ones. In the finite range models, the attractive (repulsive) interaction is described in the Lagrangian density by the {sigma} ({omega}) field. The isospin dependence of the interaction is modeled by the {rho} meson field. We submit these sets of RMF models to eleven macroscopic (experimental and empirical) constraints, used in a recent study in which 240 Skyrme parametrizations were analyzed. Such constraints cover a wide range of properties related to symmetric nuclear matter (SNM), pure neutron matter (PNM), and both SNM and PNM.
Chiral four-body interactions in nuclear matter
Energy Technology Data Exchange (ETDEWEB)
Norbert, Kaiser [Physik-Department, Technische Universitaet Muenchen (Germany)
2014-07-01
The effects of chiral four-nucleon interactions in nuclear and neutron matter are studied. The leading-order terms arising from pion-exchange in combination with the chiral 4?-vertex and the chiral NN3?-vertex are found to be very small. The contributions of reducible four-nucleon interactions generated by the method of unitary transformations are included as well. We consider also the four-nucleon interaction induced by pion-exchange and twofold ?-isobar excitation of nucleons. For most of the closed four-loop diagrams the occurring integrals over four Fermi spheres can either be solved analytically or reduced to one- or two-parameter integrals. After summing the individually large contributions from 3-ring, 2-ring and 1-ring diagrams of alternating signs, one obtains at nuclear matter saturation density ?{sub 0}=0.16 fm{sup -3} a moderate contribution of about 2 MeV to the energy per particle. The curve anti E(?) rises rapidly with density, approximately as ?{sup 3}. In pure neutron matter the chiral four-body interactions lead to a repulsive contribution that is about half as strong.
Converting of Matter to Nuclear Energy by AB-Generator
Directory of Open Access Journals (Sweden)
Alexander Bolonkin
2009-01-01
Full Text Available Problem statement: Researcher offered a new nuclear generator which allowed to convert any matter to nuclear energy in accordance with Einstein equation E = mc2. The method was based upon tapping the energy potential of a Micro Black Hole (MBH and Hawking radiation created by this MBH. Researcher did not meet the idea and its research in literature to develop the method for getting a cheap energy. Approach: As is well-known, vacuum continuously produced virtual pairs of particles and antiparticles, in particular, photons and anti-photons. MBH event horizon allowed separating them. Anti-photons can be moved to MBH and be annihilated, decreasing mass of MBH, resulting photons leave the MBH neighborhood as Hawking radiation. The offered nuclear generator (named by Researcher as AB-generator utilized Hawking radiation and injected the matter into MBH and kept MBH in a stable state with near-constant mass. Results: AB-generator can be produced gigantic energy outputs and should be cheaper than a conventional electric station by a factor of hundreds of times. One also may be used in aerospace as a photon rocket or as a power source for many vehicles. Conclusion: Many scientists expect Large Hadron Collider at CERN may be produced one MBH every second. A technology to capture them may be developed; than they may be used for the AB-generator.
Chiral relativistic model of nuclear matter including effects of confinement mechanism
International Nuclear Information System (INIS)
This work aims at constructing a model for symmetric and asymmetric nuclear matter in a relativistic approach including effects from quantum chromodynamics, in particular chiral symmetry and confinement. We consider an assembly of nucleons interacting via meson exchange. The attraction is due to a chiral invariant scalar field associated with the fluctuations of the chiral condensate. The inclusion of scalar nucleonic effects due to the quark substructure of the nucleon ensures the saturation to occur. The parameters corresponding to the scalar sector of the interaction and to the quarks confinement in the nucleon are obtained from lattice calculations. The rest of the parameters are obtained as much as possible by hadron phenomenology. With such constrained inputs, the results are nevertheless very good: this constitutes the originality of this work. In one part, we chose to work at the mean-field level in the Hartree-Fock scheme. The propagation of the scalar field in the Hartree-Fock terms induce some rearrangement effects which play an essential role in the Hugenholtz-Van Hove theorem. We discuss also the role of the tensor part of the ? interaction in the symmetry energy and the isospin dependence of the Landau effective mass. Then, in the idea to enlarge this work to neutron stars, we give the equation of state predicted by our model. The last step corresponds to the introduction of effects after the mean-field including the correlation energy due to pion loops. An important ingredient is the Landau-Migdal parameter controlling short range interactions. The correlation energy enhances the description of the saturation point of nuclear matter. (author)
Analysis of Boltzmann-Langevin dynamics in nuclear matter
Ayik, S; Colonna, M; Randrup, J; Chomaz, Ph; Colonna, M; Randrup, J
1995-01-01
The Boltzmann-Langevin dynamics of harmonic modes in nuclear matter is analyzed within linear-response theory, both with an elementary treatment and by using the frequency-dependent response function. It is shown how the source terms agitating the modes can be obtained from the basic BL correlation kernel by a simple projection onto the associated dual basis states, which are proportional to the RPA amplitudes and can be expressed explicitly. The source terms for the correlated agitation of any two such modes can then be extracted directly, without consideration of the other modes. This facilitates the analysis of collective modes in unstable matter and makes it possible to asses the accuracy of an approximate projection technique employed previously.
Reducible chiral four-body interactions in nuclear matter
Kaiser, N
2015-01-01
The method of unitary transformations generates five classes of leading-order reducible chiral four-nucleon interactions which involve pion-exchanges and a spin-spin contact-term. Their first-order contributions to the energy per particle of isospin-symmetric nuclear matter and pure neutron matter are evaluated in detail. For most of the closed four-loop diagrams the occurring integrals over four Fermi-spheres can be reduced to easily manageable one- or two-parameter integrals. One observes substantial cancelations among the different contributions arising from 2-ring and 1-ring diagrams. Altogether, the net attraction generated by the chiral four-nucleon interaction does not exceed values of $-1.3$\\,MeV for densities $\\rho<2\\rho_0$.
Analysis of Boltzmann-Langevin dynamics in nuclear matter
International Nuclear Information System (INIS)
The Boltzmann-Langevin dynamics of harmonic modes in nuclear matter is analyzed within linear-response theory, both with an elementary treatment and by utilizing the frequency-dependent response function. It is shown how the source terms agitating the modes can be obtained from the basic BL correlation kernel by a simple projection onto the associated dual basis states, which are proportional to the RPA amplitudes and can be expressed explicitly. The source terms for the correlated agitation of any two such modes can then be extracted directly, without consideration of the other modes. This facilitates the analysis of collective modes in unstable matter and makes it possible to asses the accuracy of an approximate projection technique employed previously. (orig.)
pion-rho-omega vertex in nuclear matter
Baran, Anna; Bieniek, Agnieszka; Broniowski, Wojciech
2002-01-01
Medium modifications of the pion-omega-rho vertex are analyzed in context of the omega -> pi gamma* and rho -> pi gamma* decays in nuclear matter. A relativistic hadronic model with mesons, nucleons, and Delta(1232)isobars is applied. A substantial increase of the widths for the decays omega -> pi gamma* and rho -> pi gamma* is found for photon virtualities in the range 0.3-0.6 GeV. This enhancement has a direct importance for the description of dilepton yields obtained in r...
Collective modes in a slab of interacting nuclear matter
International Nuclear Information System (INIS)
We study the properties of a slab of nuclear matter. The behaviour with the slab thickness of the particle density, kinetic energy density and surface tension are given in the non-interacting case, together with the slab free response to an external field. Next we introduce a zero-range isovector interaction among the nucleons and analyze the slab collective excitations. For moderate momenta hard and soft modes are found, which exhaust most of the excitation strength. Their position and splitting in energy favourably compares with the splitted giant dipole resonance experimentally seen in deformed nuclei. (orig.)
Relativistic spectral function of nucleons in hot nuclear matter
International Nuclear Information System (INIS)
We present a simple calculation of the nucleon self-energy in nuclear matter at finite temperature in a relativistic framework, using the real-time thermal field theory. The imaginary parts of one-loop graphs are identified with discontinuities across the unitary and the Landau cuts. We find that in general both the cuts contribute significantly to the spectral function in the region of (virtual) nucleon mass usually considered, even though the unitary cut is ignored in the literature. Furthermore, our relativistic spectral function differs from the one in nonrelativistic approximation, used in some earlier calculations.
Nuclear matter properties and relativistic mean-field theory
Chung, K. C.; C. S. Wang; Santiago, A. J.; Zhang, J. W.
2001-01-01
Nuclear matter properties are calculated in the relativistic mean field theory by using a number of different parameter sets. The result shows that the volume energy $a_1$ and the symmetry energy $J$ are around the acceptable values 16MeV and 30MeV respectively; the incompressibility $K_0$ is unacceptably high in the linear model, but assumes reasonable value if nonlinear terms are included; the density symmetry $L$ is around $100MeV$ for most parameter sets, and the symmetr...
Thermostatic properties of semi-infinite polarized nuclear matter
International Nuclear Information System (INIS)
The surface and curvature properties of semi-infinite polarized nuclear matter (SPNM) are calculated using an expansion for the Fermi integrals up to T2. A density matrix expansion is obtained for a modified form of the Seyler-Blanchard interaction. New parameters that characterize the surface and curvature properties of SPNM are introduced. The level density parameter is extracted from the low temperature expansion of the free energy and compared with previous calculations. A reasonable agreement is obtained with the parameters calculated before. copyright 1996 The American Physical Society
Quantum teleportation of nuclear matter and its investigation
International Nuclear Information System (INIS)
Since its discovery in 1993, quantum teleportation (QT) is a subject for intense theoretical and experimental studies. Experimental demonstration of QT has so far been limited to teleportation of light. In this paper, we propose a new experimental scheme for QT of nuclear matter. We show that the standard technique of nuclear physics experiment could be successfully applied for teleportation of spin states of atomic nuclei. We claim that there are no theoretical prohibitions upon a possibility of a complete Bell measurement, therefore, the implementation of all the four quantum communication channels is at least theoretically possible. A general expression for scattering amplitude of two 1/2-spin particles is given in the Bell operator basis, and the peculiarities of Bell states registration are briefly discussed
Modification of the $\\omega$-Meson Lifetime in Nuclear Matter
Kotulla, M; Mühlich, P; Anton, G; Bacelar, J C S; Bartholomy, O; Bayadilov, D; Beloglasov, Yu A; Bogendörfer, R; Castelijns, R; Credé, V; Dutz, H; Ehmanns, A; Elsner, D; Ewald, R; Fabry, I; Fuchs, M; Essig, K; Funke, Ch; Gothe, R; Gregor, R; Gridnev, A B; Gutz, E; Höffgen, S; Hoffmeister, P; Horn, I; Hössl, J; Jaegle, I; Junkersfeld, J; Kalinowsky, H; Klein, Frank; Klein, Fritz; Klempt, E; Konrad, M; Kopf, B; Krusche, B; Langheinrich, J; Löhner, H; Lopatin, I V; Lotz, J; Lugert, S; Menze, D; Messchendorp, J G; Mertens, T; Metag, V; Mosel, U; Nanova, M; Novotny, R; Ostrick, M; Pant, L M; Van Pee, H; Pfeiffer, M; Roy, A; Radkov, A; Schadmand, S; Schmidt, Ch; Schmieden, H; Schoch, B; Shende, S; Suft, G; Sumachev, V V; Szczepanek, T; Süle, A; Thoma, U; Varma, R; Walther, D; Weinheimer, Ch; Wendel, Ch
2008-01-01
The photo production of $\\omega$ mesons on the nuclei C, Ca, Nb and Pb has been measured using the Crystal Barrel/TAPS detector at the ELSA tagged photon facility in Bonn. The dependence of the $\\omega$ meson cross section on the nuclear mass number has been compared with three different types of models, a Glauber analysis, a BUU analysis of the Giessen theory group and a calculation by the Valencia theory group. In all three cases, the inelastic $\\omega$ width is found to be $130-150 \\rm{MeV/c^2}$ at normal nuclear matter density for an average 3-momentum of 1.1 GeV/c. In the restframe of the $\\omega$ meson, this inelastic $\\omega$ width corresponds to a reduction of the $\\omega$ lifetime by a factor $\\approx 30$. For the first time, the momentum dependent $\\omega$N cross section has been extracted from the experiment and is in the range of 70 mb.
Relativistic quantum field approach to nuclear matter and nuclei
International Nuclear Information System (INIS)
In the present survey, we discuss the nature and the size of relativistic mean field corrections which have recently been considered by various authors. The word approach in the title is meant to remind one that there does not yet exist a reliable relativistic quantum field theory of the many-body problem. In view of this, we shall find it instructive and useful to investigate first simplified dynamical models, and also to rely upon phenomenological approximations. Since nuclear theory essentially rests upon the shell model, most of our discussion will be devoted to relativistic corrections to the single-particle potential and wave functions. Here, the expression relativistic corrections refers to effects which directly or indirectly involve the small components of the Dirac spinor which represents the nucleon embedded in nuclear matter or in a nucleus. (orig./HSI)
Equation of state for nuclear matter based on density dependent effective interaction
Basu, D. N.
2003-01-01
An interesting method of obtaining equation of state for nuclear matter, from a density dependent M3Y interaction, by minimizing the energy per nucleon is described. The density dependence parameters of the interaction are obtained by reproducing the saturation energy per nucleon and the saturation density of spin and isospin symmetric cold infinite nuclear matter. The nuclear matter equation of state thus obtained is then used to calculate the pressure, the energy density, ...
Quark Condensates in Nuclear Matter in the Global Color Symmetry Model of QCD
Liu, Yu-Xin(Department of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871, China); Gao, Dong-feng; Guo, Hua
2003-01-01
With the global color symmetry model being extended to finite chemical potential, we study the density dependence of the local and nonlocal scalar quark condensates in nuclear matter. The calculated results indicate that the quark condensates increase smoothly with the increasing of nuclear matter density before the critical value (about 12$\\rho_0$) is reached. It also manifests that the chiral symmetry is restored suddenly as the density of nuclear matter reaches its critic...
Skyrme interaction to second order in nuclear matter
Kaiser, N
2015-01-01
Based on the phenomenological Skyrme interaction various density-dependent nuclear matter quantities are calculated up to second order in many-body perturbation theory. The spin-orbit term as well as two tensor terms contribute at second order to the energy per particle. The simultaneous calculation of the isotropic Fermi-liquid parameters provides a rigorous check through the validity of the Landau relations. It is found that published results for these second order contributions are incorrect in most cases. In particular, interference terms between $s$-wave and $p$-wave components of the interaction can contribute only to (isospin or spin) asymmetry energies. Even with nine adjustable parameters, one does not obtain a good description of the empirical nuclear matter saturation curve in the low density region $0<\\rho<2\\rho_0$. The reason for this feature is the too strong density-dependence $\\rho^{8/3}$ of several second-order contributions. The inclusion of the density-dependent term ${1\\over 6}t_3 \\r...
The Hypothesis of Nuclear Fusion in Condensed Matter: An Update
Jones, Steven; Ellsworth, John; Rees, Lawrence
2004-05-01
In our 1986 and1989 papers, we discussed the hypothesis of nuclear fusion in condensed matter and particularly in the planets and provided supporting evidence.[1,2] We continue to assert that non-thermonuclear d-Z fusion (including but not limited to d-d fusion) may occur in the core-region of the earth, and generally in hydrogen-bearing metals and minerals which are subjected to extreme off-equilibrium conditions. This hypothesis can be tested by measuring tritium and helium-3 in magmatic fluids from hot-spot volcanoes which tap plumes arising from the core-mantle boundary. In particular, magmatic waters of Kilauea, Loihi, and Icelandic volcanoes are predicted to contain significant tritium. Magmatic emissions of Kilauea demonstrated anomalous tritium content over twelve years ago[3], and a re-test of Kilauea emissions is urged along with further laboratory experiments. [1] C. DeW. Van Siclen and S. E. Jones, "Piezonuclear fusion in isotopic hydrogen molecules," J. Phys. G: Nucl. Phys. 12: 213-221 (March 1986). [2] S. E. Jones, et al., Observation of Cold Nuclear Fusion in Condensed Matter, Nature 338: 737-740 (April 1989). [4] F. Goff and G. M. McMurtry, "Tritium and stable isotopes of magmatic waters," J. Volcanology and Geothermal Research, 97: 347-396 (2000)
Chiral four-body interactions in nuclear matter
Kaiser, N
2012-01-01
An exploratory study of chiral four-nucleon interactions in nuclear and neutron matter is performed. The leading-order terms arising from pion-exchange in combination with the chiral $4\\pi$-vertex and the chiral NN$3\\pi$-vertex are found to be very small. Their attractive contribution to the energy per particle stays below $0.6\\,$MeV in magnitude for densities up to $\\rho =0.4\\,$fm$^{-3}$. We consider also the four-nucleon interaction induced by pion-exchange and twofold $\\Delta$-isobar excitation of nucleons. For most of the closed four-loop diagrams the occurring integrals over four Fermi spheres can either be solved analytically or reduced to easily manageable one- or two-parameter integrals. After summing the individually large contributions from 3-ring, 2-ring and 1-ring diagrams of alternating signs, one obtains at nuclear matter saturation density $\\rho_0=0.16\\,$fm$^{-3}$ a moderate contribution of $2.35\\,$MeV to the energy per particle. The curve $\\bar E(\\rho)$ rises rapidly with density, approximatel...
2010-01-29
...EA-09-147, NRC-2010- 0028] In the Matter of Beta Gamma Nuclear Radiology; Confirmatory Order Modifying License (Effective Immediately) I Beta Gamma Nuclear Radiology (BGNR) (Licensee) is the holder of medical License No....
Chiral symmetry in strongly interacting matter. From nuclear matter to phases of QCD
International Nuclear Information System (INIS)
This is a brief summary of topics that were presented as lectures within the programme 'New Frontiers in QCD 2010' at the Yukawa Institute of Theoretical Physics in Kyoto. The basic subject is phases and symmetry breaking patterns as they emerge from the approximate chiral symmetry of QCD. Part I focuses on the QCD interface with nuclear physics via chiral effective field theory. This includes nuclear thermodynamics and, in particular, constraints for compressed and hot baryonic matter provided by the density and temperature dependence of the chiral condensate. Part II explores aspects of the QCD phase diagram using a non-local improved version of the Polyakov-Nambu-Jona-Lasinio (PNJL) model. A prominent feature of such an approach is the occurrence of a dynamical entanglement between chiral and deconfinement crossover transitions. Comparisons with available results from lattice QCD thermodynamics will be made. (author)
Half-Skyrmions and the Equation of State for Compact-Star Matter
Dong, Huan; Kuo, T.T.S.; Lee, Hyun Kyu; Machleidt, R.; Rho, Mannque
2012-01-01
The half-skyrmions that appear in dense baryonic matter when skyrmions are put on crystals modify drastically hadron properties in dense medium and affect strongly the nuclear tensor forces, thereby influencing the equation of state (EoS) of dense nuclear and asymmetric nuclear matter. The matter comprised of half skyrmions has vanishing quark condensate but non-vanishing pion decay constant and could be interpreted as a hadronic dual of strong-coupled quark matter. We infer...
Lectures on Effective Field Theories for Nuclei, Nuclear Matter and Dense Matter
Rho, M
2002-01-01
This note is based on four lectures that I gave at the 10th Taiwan Nuclear Spring School held at Hualien, Taiwan in January 2002. It aims to correlate the old notion of Cheshire Cat Principle developed for elementary baryons to the modern notion of quark-baryon and gluon-meson "continuities" or "dualities" in dilute and dense many-body systems and predict what would happen to mesons when squeezed by nuclear matter to high density as possibly realized in compact stars. Using color-flavor locking in QCD, the vector mesons observed at low density can be described as the Higgsed gluons dressed by cloud of collective modes, i.e., pions just as they are in superdense matter, thus showing the equivalence between hidden $flavor$ gauge symmetry and explicit $color$ gauge symmetry. Instead of going into details of well-established facts, I focus on a variety of novel ideas -- some solid and some less -- that could be confirmed or ruled out in the near future.
International Nuclear Information System (INIS)
Since the research field of nuclear physics is expanding rapidly, it is becoming more imperative to develop the microscopie theory of nuclear matter physics which provides us with a unified understanding of diverse phenomena exhibited by nuclei. An estabishment of various stable mean-fields in nuclei allows us to develop the microscopie theory of nuclear collective dynamics within the mean-field approximation. The classical-level theory of nuclear collective dynamics is developed by exploiting the symplectic structure of the timedependent Hartree-Fock (TDHF)-manifold. The importance of exploring the single-particle dynamics, e.g. the level-crossing dynamics in connection with the classical order-to-chaos transition mechanism is pointed out. Since the classical-level theory os directly related to the full quantum mechanical boson expansion theory via the symplectic structure of the TDHF-manifold, the quantum theory of nuclear collective dynamics is developed at the dictation of what os developed on the classical-level theory. The quantum theory thus formulated enables us to introduce the quantum integrability and quantum chaoticity for individual eigenstates. The inter-relationship between the classical-level and quantum theories of nuclear collective dynamics might play a decisive role in developing the quantum theory of many-body problems. (orig.)
Zhou, Zhengzhen; Guo, Laodong
2015-06-19
Colloidal retention characteristics, recovery and size distribution of model macromolecules and natural dissolved organic matter (DOM) were systematically examined using an asymmetrical flow field-flow fractionation (AFlFFF) system under various membrane size cutoffs and carrier solutions. Polystyrene sulfonate (PSS) standards with known molecular weights (MW) were used to determine their permeation and recovery rates by membranes with different nominal MW cutoffs (NMWCO) within the AFlFFF system. Based on a ?90% recovery rate for PSS standards by the AFlFFF system, the actual NMWCOs were determined to be 1.9kDa for the 0.3kDa membrane, 2.7kDa for the 1kDa membrane, and 33kDa for the 10kDa membrane, respectively. After membrane calibration, natural DOM samples were analyzed with the AFlFFF system to determine their colloidal size distribution and the influence from membrane NMWCOs and carrier solutions. Size partitioning of DOM samples showed a predominant colloidal size fraction in the <5nm or <10kDa size range, consistent with the size characteristics of humic substances as the main terrestrial DOM component. Recovery of DOM by the AFlFFF system, as determined by UV-absorbance at 254nm, decreased significantly with increasing membrane NMWCO, from 45% by the 0.3kDa membrane to 2-3% by the 10kDa membrane. Since natural DOM is mostly composed of lower MW substances (<10kDa) and the actual membrane cutoffs are normally larger than their manufacturer ratings, a 0.3kDa membrane (with an actual NMWCO of 1.9kDa) is highly recommended for colloidal size characterization of natural DOM. Among the three carrier solutions, borate buffer seemed to provide the highest recovery and optimal separation of DOM. Rigorous calibration with macromolecular standards and optimization of system conditions are a prerequisite for quantifying colloidal size distribution using the flow field-flow fractionation technique. In addition, the coupling of AFlFFF with fluorescence EEMs could provide new insights into DOM heterogeneity in different colloidal size fractions. PMID:25958093
Strangeness production from $\\pi N$ collisions in nuclear matter
Tsushima, K; Thomas, A W
2000-01-01
Kaon production in pion-nucleon collisions in nuclear matter is studied in the resonance model. To evaluate the in-medium modification of the reaction amplitude as a function of the baryonic density we introduce relativistic, mean-field potentials for the initial, final and intermediate mesonic and baryonic states. These vector and scalar potentials were calculated using the quark meson coupling model. The in-medium kaon production cross sections in pion-nucleon interactions for reaction channels with $\\Lambda$ and $\\Sigma$ hyperons in the final state were calculated at the baryonic densities appropriate to relativistic heavy ion collisions. Contrary to earlier work which has not allowed for the change of the cross section in medium, we find that the data for kaon production are consistent with a repulsive $K^+$-nucleus potential.
The nuclear matter equation of state including light clusters
International Nuclear Information System (INIS)
The equation of state (EOS) of nuclear matter at moderate temperature and density with various proton fractions is considered, in particular the region of medium excitation energy given by the temperature range T?30 MeV and the baryon density range ?B?1014.2 g/cm3. In addition to the mean-field effects, the formation of few-body correlations, in particular, the light bound clusters up to the alpha particle (1?A?4), is of interest. Calculation based on the relativistic mean-field theory with the parameter set TM1 is presented. We show results for different values of the asymmetry parameter, and ? equilibrium is considered as a special case. The medium modification of the light clusters is described by self-energy and Pauli blocking effects, using an effective nucleon-nucleon interaction potential
Equation of state of quark-nuclear matter
Krein, G I
2002-01-01
Quark-nuclear matter (QNM) is a many-body system containing hadrons and deconfined quarks. Starting from a microscopic quark-meson coupling (QMC) Hamiltonian with a density dependent quark-quark interaction, an effective quark-hadron Hamiltonian is constructed via a mapping procedure. The mapping is implemented with a unitary operator such that composites are redescribed by elementary-particle field operators that satisfy canonical commutation relations in an extended Fock space. Application of the unitary operator to the microscopic Hamiltonian leads to effective, hermitian operators that have a clear physical interpretation. At sufficiently high densities, the effective Hamiltonian contains interactions that lead to quark deconfinement. The equation of state of QNM is obtained using standard many-body techniques with the effective quark-hadron Hamiltonian. At low densities, the model is equivalent to a QMC model with confined quarks. Beyond a critical density, when quarks start to deconfine, the equation of...
Resilience of nuclear matter in light ion induced reactions
International Nuclear Information System (INIS)
Cavitation and heating of the target nucleus in the first instances of 3He-induced collisions in the GeV/u range are investigated in an intranuclear cascade model for the formation of this structure and a stochastic one-body dynamics calculation to study its evolution. The hard collisions having essentially ceased when the structure is fully developed, the latter model is particularly suited to study the possible break-up of the system. It is shown, however, that the target recovers a spherical shape rather rapidly, and has thus a good chance to decay by standard evaporation, justifying the use of a cascade + evaporation model to analyze the data. It is also shown that the system should be modified to break up into pieces instead of recovering a compact shape: in these reactions, it is thus expected that nuclear matter is resilient to shape deformation and thermal excitation. (author)
Dynamics of hot and dense nuclear and partonic matter
Energy Technology Data Exchange (ETDEWEB)
Bratkovskaya, E. L., E-mail: Elena.Bratkovskaya@th.physik.uni-frankfurt.de [Frankfurt University, Institute for Theoretical Physics (Germany); Cassing, W. [Giessen University, Institute for Theoretical Physics (Germany); Linnyk, O. [Frankfurt University, Institute for Theoretical Physics (Germany); Konchakovski, V. P. [Giessen University, Institute for Theoretical Physics (Germany); Voronyuk, V. [Frankfurt University, FIAS (Germany); Ozvenchuk, V. [Frankfurt University, Institute for Theoretical Physics (Germany)
2012-06-15
The dynamics of hot and dense nuclear matter is discussed from the microscopic transport point of view. The basic concepts of the Hadron-String-Dynamical transport model (HSD)-derived from Kadanoff-Baym equations in phase phase-are presented as well as 'highlights' of HSD results for different observables in heavy-ion collisions from 100 A MeV (SIS) to 21 A TeV(RHIC) energies. Furthermore, a novel extension of the HSD model for the description of the partonic phase-the Parton-Hadron-String-Dynamics (PHSD) approach-is introduced. PHSD includes a nontrivial partonic equation of state-in line with lattice QCD-as well as covariant transition rates from partonic to hadronic degrees of freedom. The sensitivity of hadronic observables to the partonic phase is demonstrated for relativistic heavy-ion collisions from the FAIR/NICA up to the RHIC energy regime.
Dynamics of hot and dense nuclear and partonic matter
Bratkovskaya, E. L.; Cassing, W.; Linnyk, O.; Konchakovski, V. P.; Voronyuk, V.; Ozvenchuk, V.
2012-06-01
The dynamics of hot and dense nuclear matter is discussed from the microscopic transport point of view. The basic concepts of the Hadron-String-Dynamical transport model (HSD)—derived from Kadanoff-Baym equations in phase phase—are presented as well as "highlights" of HSD results for different observables in heavy-ion collisions from 100 A MeV (SIS) to 21 A TeV(RHIC) energies. Furthermore, a novel extension of the HSD model for the description of the partonic phase—the Parton—Hadron-String-Dynamics (PHSD) approach—is introduced. PHSD includes a nontrivial partonic equation of state—in line with lattice QCD—as well as covariant transition rates from partonic to hadronic degrees of freedom. The sensitivity of hadronic observables to the partonic phase is demonstrated for relativistic heavy-ion collisions from the FAIR/NICA up to the RHIC energy regime.
Finite baryon density in lattice simulations and nuclear matter
International Nuclear Information System (INIS)
A simple model for the partition function of an interacting nucleon gas can explain the early onset of the baryon density observed when using staggered fermions on the lattice at finite chemical potential. The onset, which is very sensitive to the number of lightest nucleon states formed, represents the point where condensation into nuclear matter occurs. The lattice simulations have been done with staggered fermions or 4 degenerate valence quarks, which can bind into 40 lightest nucleons for which the model can fit the early onset as found on the lattice for various quark masses. The statistical model contains scalar interactions, producing attractive energies scaling as mN-2, among nucleons which propagate in effective volumes that exclude the hard nucleon cores determined by m?. Extrapolating the number of flavours and masses to the values in nature, where we have 4 lowest nucleon states, the model shows and onset close to the nucleon mass as desired. (orig.)
Thermodynamic properties of nuclear matter with three-body forces
Somà, V.; Bo?ek, P.
2009-08-01
We calculate thermodynamic quantities in symmetric nuclear matter within the self-consistent Green's functions method including three-body forces. The thermodynamic potential is computed directly from a diagrammatic expansion, implemented with the CD-Bonn and Nijmegen nucleon-nucleon potentials and the Urbana three-body forces. We present results for entropy and pressure up to temperatures of 20 MeV and densities of 0.32fm-3. While the pressure is sensitive to the inclusion of three-body forces, the entropy is not. The unstable spinodal region is identified and the critical temperature associated to the liquid-gas phase transition is determined. When three-body forces are added we find a strong reduction of the critical temperature, obtaining Tc?12MeV.
Behera, B; Routray, T R; Centelles, M
2015-01-01
The properties of spin polarized pure neutron matter and symmetric nuclear matter are studied using the finite range simple effective interaction, upon its parametrization revisited. Out of the total twelve parameters involved, we now determine ten of them from nuclear matter, against the nine parameters in our earlier calculation, as required in order to have predictions in both spin polarized nuclear matter and finite nuclei in unique manner being free from uncertainty found using the earlier parametrization. The information on the effective mass splitting in polarized neutron matter of the microscopic calculations is used to constrain the one more parameter, that was earlier determined from finite nucleus, and in doing so the quality of the description of finite nuclei is not compromised. The interaction with the new set of parameters is used to study the possibilities of ferromagnetic and antiferromagnetic transitions in completely polarized symmetric nuclear matter. Emphasis is given to analyze the resul...
Empirical observations on the unpredictable behavior of nuclear matter
International Nuclear Information System (INIS)
While many aspects of matter are unpredictable from basic principles, there are some that are susceptible to empirical descriptions which can be quite accurate and beautiful. One such example from the field of ''Nuclear Matter Under Extreme Conditions'' is the distribution of the number of particles produced, or alternatively, of the energy carried by these particles, in energetic collisions of atomic nuclei. The present work consists of a series of published scientific papers on measurements of the distribution of particles produced, or the energy carried by these particles, in collisions of various nuclei, spanning more than a decade of research. Due to the unpredictability of the theory, the work includes empirical studies of the regularity of the measured distributions from which significant knowledge is gained. The aesthetics of this subject derives from the physical beauty of the measured curves, the characteristic changes of shape with different species of nuclei, and the deep understanding obtained by the use of a simple and elegant mathematical function to describe the data
Study of the nuclear matter flow with the multidetector INDRA
International Nuclear Information System (INIS)
The work presented in this thesis relates to the study of the products which are not emitted by the statistical deexcitation of the projectile and target. The experiment on which this work is based on was performed at GANIL with the detector INDRA on two systems: 36 Ar + 58 Ni and 129 Xe + 119 Sn. A whole characterization (mass, composition, multiplicities and energy properties) of mid-rapidity emission has been done for the system 36 Ar + 58 Ni between 52 and 95 A.MeV. The amount of matter associated to this emission seems to be independent of the incident energy and directly linked with the centrality of the collision. The available energy per nucleon for the production of mid-rapidity products seems to be insensitive to the impact parameter. A systematic study of the nuclear matter in-plane flow has also been carried out. It has been established that the usual methods for reaction plane determination do not allow one to measure accurately the value of flow parameter at intermediate energies. Nevertheless, the inversion energy of the system 36 Ar + 58 Ni can be calculated for central collisions. This energy is independent of the nature of the products. Its value and the features of the mid-rapidity emission should allow one to extract in-medium nucleon-nucleon cross section by comparison with theoretical results. (author)
Nuclear matter in relativistic non-linear models
International Nuclear Information System (INIS)
We have determined the equation of state of nuclear matter according to relativistic non-linear models. In particular, we are interested in regions of high density and/or high temperature, in which the thermodynamic functions have very different behaviours depending on which model one uses. The high-density behaviour is, for example, a fundamental ingredient for the determination of the maximum mass of neutron stars. As an application, we have studied the process of two-pion annihilation into e+e- pairs in dense and hot matter. Accordingly, we have determined the way in which the non-linear terms modify the meson propagators occurring in this process. Our results have been compared with those obtained for the meson propagators in free space. We have found models that give an enhancement of the dilepton production rate in the low invariant mass region. Such an enhancement is in good agreement with the invariant mass dependence of the data obtained in heavy ions collisions at CERN/SPS energies. (author)
Mean field effects in hot compressed nuclear matter
Energy Technology Data Exchange (ETDEWEB)
Molitoris, J.J.; Bonasera, A.; Winer, B.L.; Stoecker, H.
1988-03-01
We study effects of the mean field in hot compressed nuclear matter in the context of the Vlasov Uehling-Uhlenbeck theory. The expansion of a spherical distribution at different temperatures is studied along with collisions of Nb+Nb and Au+Au at lab energies from 50 to 1050 MeV/nucleon. In both the expansion and the actual heavy ion collision simulation, a transition behavior is seen only at the lowest temperature (T<10 MeV) or bombarding energy (E = 50 MeV/nucleon), where the attractive part of the mean field is able to bind the expanding matter. At the lowest energy one thus sees the formation of a central residue, whereas at higher bombarding energies there is complete disintegration of the centrally colliding nuclei. The spectrum of emitted nucleons is found to be much hotter than the kinetic energy spectrum of the central emitting region. The extracted temperature slope parameters are in agreement with recent data.
Mean field effects in hot compressed nuclear matter
International Nuclear Information System (INIS)
We study effects of the mean field in hot compressed nuclear matter in the context of the Vlasov Uehling-Uhlenbeck theory. The expansion of a spherical distribution at different temperatures is studied along with collisions of Nb+Nb and Au+Au at lab energies from 50 to 1050 MeV/nucleon. In both the expansion and the actual heavy ion collision simulation, a transition behavior is seen only at the lowest temperature (T<10 MeV) or bombarding energy (E = 50 MeV/nucleon), where the attractive part of the mean field is able to bind the expanding matter. At the lowest energy one thus sees the formation of a central residue, whereas at higher bombarding energies there is complete disintegration of the centrally colliding nuclei. The spectrum of emitted nucleons is found to be much hotter than the kinetic energy spectrum of the central emitting region. The extracted temperature slope parameters are in agreement with recent data
Short-range correlations in quark and nuclear matter
International Nuclear Information System (INIS)
In the first part of this thesis, the role of short-range correlations in quark matter is explored within the framework of the Nambu-Jona-Lasinio model. Starting from a next-to-leading order expansion in the inverse number of the quark colors, a fully self-consistent model constructed that employs the close relations between spectral functions and self-energies. In contrast to the usual quasiparticle approximations, this approach allows the investigation of the collisional broadening of the quark spectral function. Numerical calculations at various chemical potentials and zero temperature show that the short-range correlations do not only induce a finite width of the spectral function but also have some influence on the structure of the chiral phase transition. In the second part of this thesis, the temperature and density dependence of the nucleon spectral function in symmetric nuclear matter is investigated. The short-range correlations can be well described by a simple, self-consistent model on the one-particle-two-hole and two-particle-one-hole level (1p2h, 2p1h). The thermodynamically consistent description of the mean-field properties of the nucleons is ensured by incorporating a Skyrme-type potential. Calculations at temperatures and densities that can also be found in heavy-ion collisions or supernova explosions and the formation of neutron stars show that the correlations saturate at high temperatures and densities. (orig.)
Short-range correlations in quark and nuclear matter
Energy Technology Data Exchange (ETDEWEB)
Froemel, Frank
2007-06-15
In the first part of this thesis, the role of short-range correlations in quark matter is explored within the framework of the Nambu-Jona-Lasinio model. Starting from a next-to-leading order expansion in the inverse number of the quark colors, a fully self-consistent model constructed that employs the close relations between spectral functions and self-energies. In contrast to the usual quasiparticle approximations, this approach allows the investigation of the collisional broadening of the quark spectral function. Numerical calculations at various chemical potentials and zero temperature show that the short-range correlations do not only induce a finite width of the spectral function but also have some influence on the structure of the chiral phase transition. In the second part of this thesis, the temperature and density dependence of the nucleon spectral function in symmetric nuclear matter is investigated. The short-range correlations can be well described by a simple, self-consistent model on the one-particle-two-hole and two-particle-one-hole level (1p2h, 2p1h). The thermodynamically consistent description of the mean-field properties of the nucleons is ensured by incorporating a Skyrme-type potential. Calculations at temperatures and densities that can also be found in heavy-ion collisions or supernova explosions and the formation of neutron stars show that the correlations saturate at high temperatures and densities. (orig.)
Neutron-Proton Mass Difference in Nuclear Matter and in Finite Nuclei and the Nolen-Schiffer Anomaly
Directory of Open Access Journals (Sweden)
Yakhshiev U.T.
2010-04-01
Full Text Available The neutron-proton mass di?erence in (isospin asymmetric nuclear matter and ?nite nuclei is studied in the framework of a medium-modi?ed Skyrme model. The proposed e?ective Lagrangian incorporates both the medium in?uence of the surrounding nuclear environment on the single nucleon properties and an explicit isospin-breaking e?ect in the mesonic sector. Energy-dependent charged and neutral pion optical potentials in the s- and p-wave channels are included as well. The present approach predicts that the neutron-proton mass di?erence is mainly dictated by its strong part and that it markedly decreases in neutron matter. Furthermore, the possible interplay between the e?ective nucleon mass in ?nite nuclei and the Nolen-Schi?er anomaly is discussed. In particular, we ?nd that a correct description of the properties of mirror nuclei leads to a stringent restriction of possible modi?cations of the nucleon’s e?ective mass in nuclei.
The phase diagram of nuclear and quark matter at high baryon density
Fukushima, Kenji; Sasaki, Chihiro
2013-01-01
We review theoretical approaches to explore the phase diagram of nuclear and quark matter at high baryon density. We first look over the basic properties of quantum chromodynamics (QCD) and address how to describe various states of QCD matter. In our discussions on nuclear matter we cover the relativistic mean-field model, the chiral perturbation theory, and the approximation based on the large-Nc limit where Nc is the number of colors. We then explain the liquid-gas phase t...
International Nuclear Information System (INIS)
Non-destructive analytical methods based on interactions of nuclear radiation with matter are overviewed in this chapter of the textbook. The three major categories discussed are Moessbauer spectroscopy based on the nuclear resonance absorption of gamma radiation, positronium chemistry developed from the study of the interaction of positive beta radiation with matter, and the chemistry of muonium and muonic atoms connected with the interaction of mesons with matter. (R.P.)
Sum rule in nuclear giant monopole resonance and incompressibility of nuclear matter
International Nuclear Information System (INIS)
The isoscalar giant monopole resonance for finite nuclei and the nuclear matter incompressibility are studied in a consistent relativistic approach, which achieves a great success in describing the properties of nuclear ground states. The consistency in the relativistic random phase approximation (RRPA) built on the relativistic mean field (RMF) ground states are investigated. The RMF wave function of nucleus and the particle-hole residual interactions in RRPA are calculated from a same effective Lagrangian. A fully consistent treatment of RRPA with the RMF approximation, i.e. no sea approximation, has to include not only the positive particle-hole excitation, but also the pairs formed from the Dirac states and Fermi states. The energy inverse weighted sum rule for the isoscalar giant monopole resonance is studied in the constrained RMF, which verifies the important contribution from the Dirac state. A comparison between experimental and calculated energies of isoscalar giant monopole energies points to a value of 250-270 MeV for the nuclear matter incompressibility
How far is normal nuclear matter from the chiral symmetry restoration?
Mishustin, I. N.; Satarov, L. M.; Greiner, W.
2003-01-01
Properties of cold nuclear matter are studied within a generalized Nambu-Jona-Lasinio model formulated on the level of constituent nucleons. The model parameters are chosen to reproduce simultaneously the observed nucleon and pion masses in vacuum as well as saturation properties of nuclear matter. The strongest constraints on these parameters are given by the empirical values of the nucleon effective mass and compression modulus at nuclear saturation density. A preferable v...
A new explanation to the cold nuclear matter effects in heavy ion collisions
Liu, Zhi-Feng
2014-01-01
The J/Psi cross section ratios of p-A/p-p under different collision energy is calculated with cold nuclear matter effects redefined in this paper. The advantage of these new definitions is that all cold nuclear matter effects have clear physical origins.The radios are compared with the corresponding experiment data and that calculated with classic nuclear effects. The ratios calculated with new definitions can reproduce almost all existing J/Psi measurements in p-A collisions more accuratly than that calculated with classic nuclear effects. Hence, this paper presents a new approach to explain cold nuclear effects in the hardproduction of quarkonium.
Multiplicity and cold-nuclear matter effects from Glauber-Gribov theory at LHC
Arsene, I C; Bravina, L.; Kaidalov, A. B.; Tywoniuk, K.; Zabrodin, E.
2007-01-01
We present predictions for nuclear modification factor in proton-lead collisions at LHC energy 5.5 TeV from Glauber-Gribov theory of nuclear shadowing. We have also made predictions for baseline cold-matter nuclear effects in lead-lead collisions at the same energy.
Relativistic description of BCS-BEC crossover in nuclear matter
International Nuclear Information System (INIS)
We study theoretically the di-neutron spatial correlations and the crossover from superfluidity of neutron Cooper pairs in the 1S0 pairing channel to Bose-Einstein condensation (BEC) of di-neutron pairs for both symmetric and neutron matter in the microscopic relativistic pairing theory. We take the bare nucleon-nucleon interaction Bonn-B in the particle-particle channel and the effective interaction PK1 of the relativistic mean-field approach in the particle-hole channel. It is found that the spatial structure of neutron Cooper pair wave function evolves continuously from BCS-type to BEC-type as density decreases. We see a strong concentration of the probability density revealed for the neutron pairs in the fairly small relative distance around 1.5 fm and the neutron Fermi momentum kFn element of [0.6,1.0] fm-1. However, from the effective chemical potential and the quasiparticle excitation spectrum, there is no evidence for the appearance of a true BEC state of neutron pairs at any density. The most BEC-like state may appear at kFn?0.2 fm-1 by examining the density correlation function. From the coherence length and the probability distribution of neutron Cooper pairs as well as the ratio between the neutron pairing gap and the kinetic energy at the Fermi surface, some features of the BCS-BEC crossover are seen in the density regions, 0.05 fm-1Fn-1, fob>Fn-1, for the symmetric nuclear (pure neutron) matter.
Functional renormalization group approach to neutron matter
Directory of Open Access Journals (Sweden)
Matthias Drews
2014-11-01
Full Text Available The chiral nucleon-meson model, previously applied to systems with equal number of neutrons and protons, is extended to asymmetric nuclear matter. Fluctuations are included in the framework of the functional renormalization group. The equation of state for pure neutron matter is studied and compared to recent advanced many-body calculations. The chiral condensate in neutron matter is computed as a function of baryon density. It is found that, once fluctuations are incorporated, the chiral restoration transition for pure neutron matter is shifted to high densities, much beyond three times the density of normal nuclear matter.
Study of Charmonium Production in Asymmetric Nuclear Collisions by the PHENIX Experiment at RHIC
,
2015-01-01
The measurement of quarkonia production in relativistic heavy ion collisions provides a powerful tool for studying the properties of the hot and dense matter created in these collisions. To be really useful, however, such measurements must cover a wide range of quarkonia states and colliding species. The PHENIX experiment at RHIC has successfully measured J/psi, psi-prime, chi_c and Upsilon production in different colliding systems at various energies. In this talk I will present recent results from the PHENIX collaboration on charmonium production in d+Au, Cu+Au and U+U collisions at 200 GeV/c.
Experimental aspects of quarkonia production and suppression in cold and hot nuclear matter
Frawley, A D
2015-01-01
When heavy Quarkonia are formed in collisions between between nuclei, their production cross section is modified relative to that in p+p collisions. The physical effects that cause this modification fall into two categories. Hot matter effects are due to the large energy density generated in the nuclear collision, which disrupts the formation of the quarkonium state. Cold nuclear matter effects are due to the fact that the quarkonium state is created in a nuclear target. I will review experimental aspects of quarkonia production due to both hot and cold matter effects.
International Nuclear Information System (INIS)
Full text : Large Hadron Collider at the European Center for Nuclear Research, Geneva Switzerland is the biggest Collider and Physics experiment in history. Over the last 30-35 years a lot of efforts have been made to search for QGP - new phases of matter under extreme conditions of high temperature and baryon density, as predicted by Quantum Chromodynamics. In 2000 CERN announced some evidences for the existence of a new state of matter. In this article it is discussed some possibilities to identify the nuclear matter under extreme conditions of high temperature and baryon density -newly created matter in ultra-relativistic heavy ion collisions
Resilience of nuclear matter in light ion induced reactions
International Nuclear Information System (INIS)
Cavitation and heating of the target nucleus in the first instances of 3He-induced collisions in the GeV/nucleon range are investigated in an intranuclear cascade model for the formation of this structure and a stochastic one-body dynamics calculation to study its evolution. The hard collisions having essentially ceased when the structure is fully developed, the latter model is particularly suited to study the possible breakup of the system. It is shown, however, that the target recovers a spherical shape rather rapidly, and has thus a good chance to decay by standard evaporation, justifying the use of a cascade + evaporation model to analyze the data. It is also shown that the system has to be much more modified to break up into pieces instead of recovering a compact shape: in these reactions, it is thus expected that nuclear matter is resilient to shape deformation and thermal excitation. Arguments are given to explain that expansion of the system, not important in these reactions, is required to overcome this resilience. copyright 1997 The American Physical Society
Zero sound and the renormalization scale in relativistic nuclear matter
International Nuclear Information System (INIS)
In this paper we report a study on the poles of the propagators of ? and ? mesons in the space-like region. In this region a zero sound can appear (a collective mode having a dispersion relation analogue to that obtained in sound propagation, but appearing at zero temperature) when the nucleon-nucleon interaction used is sufficiently repulsive. We have determined this zero sound by using a relativistic Hartree approximation, a model in which the vacuum fluctuations depend on a renormalization scale. Two renormalization schemes, corresponding to two different values of this scheme are physically acceptable. The first one corresponds to the relativistic Hartree approximation usually utilized, which minimizes the three and four body vacuum interactions. This leads to an incompressibility module which is two times higher than its experimental value. The second procedure minimizes the tree and four body interactions in the medium at saturation density, thus permitting the correct reproduction of the nuclear matter compressibility. We have shown that the zero sound which appears near the saturation density with the pure Hartree approximation occurs now at a density which is two times higher than the saturation density when the second choice of renormalization scale is done
Relativistic mean-field fit to microscopic results in nuclear matter
International Nuclear Information System (INIS)
The results of a recent relativistic Dirac-Brueckner calculation of nuclear matter are fitted to different versions of the relativistic mean-field model. It is shown that the non-linear mean-field model and the linear model with a density-dependent scalar meson mass describe well the binding energy of nuclear matter over a wide range of nuclear densities. The scalar and vector components of the self-energy, however, are not individually reproduced correctly in the whole fitted window. Nevertheless, the parameterization, which may be considered to be equivalent to the relativistic G-matrix in the range of normal nuclear densities, is found. (author)
Relativistic mean-field fit to microscopic results in nuclear matter
Energy Technology Data Exchange (ETDEWEB)
Gmuca, S. (Slovenska Akademia Vied, Bratislava (Czechoslovakia). Fyzikalny Ustav)
1991-07-01
The results of a recent relativistic Dirac-Brueckner calculation of nuclear matter are fitted to different versions of the relativistic mean-field model. It is shown that the non-linear mean-field model and the linear model with a density-dependent scalar meson mass describe well the binding energy of nuclear matter over a wide range of nuclear densities. The scalar and vector components of the self-energy, however, are not individually reproduced correctly in the whole fitted window. Nevertheless, the parameterization, which may be considered to be equivalent to the relativistic G-matrix in the range of normal nuclear densities, is found. (author).
Influence of spin polarizability on liquid gas phase transition in the nuclear matter
Rezaei, Z; Bordbar, G H
2015-01-01
In this paper, we investigate the liquid gas phase transition for the spin polarized nuclear matter. Applying the lowest order constrained variational (LOCV) method, and using two microscopic potentials, $AV_{18}$ and $UV_{14}$+TNI, we calculate the free energy, equation of state, order parameter, entropy, heat capacity and compressibility to derive the critical properties of spin polarized nuclear matter. Our results indicate that for the spin polarized nuclear matter, the second order phase transition takes place at lower temperatures with respect to the unpolarized one. It is also shown that the critical temperature of our spin polarized nuclear matter with a specific value of spin polarization parameter is in good agreement with the experimental result.
Properties of hot nuclear and neutron matter in a relativistic Hartree-Fock theory
International Nuclear Information System (INIS)
Relativistic Hartree-Fock equations are derived for an infinite system of mesons and baryons based on thermo field dynamics and Walecka's model. The properties of nuclear and neutron matter are studied for various temperatures and densities
Effect of sound branch of pion on non-mesonic ? decay in nuclear matter
International Nuclear Information System (INIS)
It is studied the effect of the sound branch of pion on the non-mesonic decay width of the ? in nuclear matter. It is funded that its effect is sensitive to the energy release and the correlation parameter g'
Phase space study of Friedel oscillations close to the surface of half infinite nuclear matter
International Nuclear Information System (INIS)
The Wigner function of half infinite nuclear matter using the infinite wall and the Woods Saxon potentials is calculated. The oscillatory structure is investigated in detail. The accuracy of several semiclassical approximations to the Wigner function is discussed. (orig.)
Variational Calculation for the Equation of State of Nuclear Matter at Finite Temperatures
Kanzawa, H; Sumiyoshi, K; Takano, M
2007-01-01
An equation of state (EOS) for uniform nuclear matter is constructed at zero and finite temperatures with the variational method starting from the realistic nuclear Hamiltonian composed of the Argonne V18 and UIX potentials. The energy is evaluated in the two-body cluster approximation with the three-body-force contribution treated phenomenologically so as to reproduce the empirical saturation conditions. The obtained energies for symmetric nuclear matter and neutron matter at zero temperature are in good agreement with those by Akmal, Pandharipande and Ravenhall at low densities. At high densities, the EOS is stiffer, and the maximum mass of the neutron star is 2.3 M . At finite temperatures, a variational method by Schmidt and Pandharipande is employed to evaluate the free energy, which is used to derive various thermodynamic quantities of nuclear matter necessary for supernova simulations. The result of this variational method at finite temperatures is found to be self-consistent.
Low-density clustering effects of Skyrme interactions in nuclear matter
International Nuclear Information System (INIS)
An orthonormal set of single-nucleon orbital functions, explicitly satisfying the Hartree-Fock equations for occupied states, is introduced and shown to display, assuming several parametrizations of the Skyrme interaction, ?-clustering effects at low densities in nuclear matter
Nuclear spin structure in dark matter search: The finite momentum transfer limit
Bednyakov, V. A.; Simkovic, F.
2006-01-01
Spin-dependent elastic scattering of weakly interacting massive dark matter particles (WIMP) off nuclei is reviewed. All available, within different nuclear models, structure functions S(q) for finite momentum transfer (q>0) are presented. These functions describe the recoil energy dependence of the differential event rate due to the spin-dependent WIMP-nucleon interactions. This paper, together with the previous paper ``Nuclear spin structure in dark matter search: The zero...
Derivative-coupling models and the nuclear-matter equation of state
International Nuclear Information System (INIS)
The equation of state of saturated nuclear matter is derived using two different derivative-coupling Lagrangians. We show that both descriptions are equivalent and can be obtained from the ?-? model through an appropriate rescaling of the coupling constants. We introduce generalized forms of this rescaling to study the correlations amongst observables in infinite nuclear matter, in particular, the compressibility and the effective nucleon mass. (orig.)
Do Skyrme forces that fit nuclear matter work well in finite nuclei?
Stevenson, P D; Stone, J R; Dutra, M
2012-01-01
A shortlist of Skyrme force parameterizations, recently found to have passed a series of constraints relating to nuclear matter properties is analyzed for their ability to reproduce data in finite nuclei. We analyse binding energies, isotope shifts and fission barriers. We find that the subset of forces have no common ability to reproduce (or otherwise) properties of finite nuclei, despite passing the extensive range of nuclear matter constraints.
Scaled variance, skewness, and kurtosis near the critical point of nuclear matter
Vovchenko, V.; Anchishkin, D. V.; Gorenstein, M I; Poberezhnyuk, R. V.
2015-01-01
The van der Waals (VDW) equation of state predicts the existence of a first-order liquid-gas phase transition and contains a critical point. The VDW equation with Fermi statistics is applied to a description of the nuclear matter. The nucleon number fluctuations near the critical point of nuclear matter are studied. The scaled variance, skewness, and kurtosis diverge at the critical point. It is found that the crossover region of the phase diagram is characterized by the lar...
On the Manifestation of Chiral Symmetry in Nuclei and Dense Nuclear Matter
Brown, G. E.; Rho, Mannque
2001-01-01
This article reviews our view on how chiral symmetry, its pattern of breaking and restoration under extreme conditions manifest themselves in the nucleon, nuclei, nuclear matter and dense hadronic matter. Topics treated are nucleon structure in terms of chiral symmetry, "first-principle" (QCD) calculations of the properties of finite nuclei effectuated by embedding the ``standard nuclear physics approach" into the framework of effective field theories of nuclei with predicti...
Quasi-stationary nonlinear waves in nuclear matter close to pion condensation
International Nuclear Information System (INIS)
The nuclear hydrodynamic model is extended to include the fluctuating spin-isospin density and its interaction with the nuclear matter density. Using the TDHF equations, it is shown that the dynamics of these densities interacting with the pion field can be expressed in terms of the generalized pressures derivable from the generalized nuclear matter equation of state. A phenomenological Skyrme interaction model is used to obtain these pressures. A theory of pion-like spin-isospin quasi-stationary nonlinear waves is formulated from the generalized hydroequations describing the dynamics of a coupled pion nuclear matter system. In the lowest order of nonlinearity, it is proved that the amplitude of the spin-isospin sound wave satisfies a nonlinear Schroedinger equation. The solution of these equations is the amplitude modulated pion-like solitary waves in nuclear matter. When this matter is near the pion condensate, the speed of these nonlinear waves is much smaller than that of the ordinary sound waves. An implication of the solitary waves excited in such nuclear matter produced in heavy ion collisions is discussed. The characteristic signature of breaking of such waves, produced in a heavy ion central collision, is the emission of a delayed component of correlated nucleons (possibly also with pion) peaked in the forward direction. It may be that the lighter nuclei 3He and 3H are produced through such a mechanism. (orig.)hanism. (orig.)
Field-theoretical description of nuclear matter with only the pion-nucleon interaction
International Nuclear Information System (INIS)
A relativistic Lagrangian for the nuclear matter consisting of nucleons and pions with a pseudoscalar interaction term is considered. It is shown that a nonrelativistic reduction of the problem automatically introduces a Lorentz scalar, isoscalar coupling of nucleons with two correlated pions. The corresponding Hamiltonian is used to study the properties of infinite nuclear matter nonperturbatively, treating both the nucleons and pions as quantized fields. The model is shown to reproduce the characteristic nuclear matter properties very nicely without the necessity of ? and ? fields, as is usually done in the mean field Walecka model. The corresponding equation of state for zero temperature nuclear matter is calculated and is shown to be consistent with the known phenomenological equations of state. The binding energy of nuclear matter is calculated to be 15.3 MeV at a saturation density of 0.153 fm-3. The model reproduces a softer nuclear matter with the incompressibility of 134 MeV. copyright 1996 The American Physical Society
Energy Technology Data Exchange (ETDEWEB)
Kahlau, R.; Bock, D.; Schmidtke, B.; Rössler, E. A., E-mail: ernst.roessler@uni-bayreuth.de [Experimentalphysik II, Universität Bayreuth, 95440 Bayreuth (Germany)
2014-01-28
Dielectric spectroscopy as well as {sup 2}H and {sup 31}P nuclear magnetic resonance spectroscopy (NMR) are applied to probe the component dynamics of the binary glass former tripropyl phosphate (TPP)/polystyrene (PS/PS-d{sub 3}) in the full concentration (c{sub TPP}) range. In addition, depolarized light scattering and differential scanning calorimetry experiments are performed. Two glass transition temperatures are found: T{sub g1}(c{sub TPP}) reflects PS dynamics and shows a monotonic plasticizer effect, while the lower T{sub g2}(c{sub TPP}) exhibits a maximum and is attributed to (faster) TPP dynamics, occurring in a slowly moving or immobilized PS matrix. Dielectric spectroscopy probing solely TPP identifies two different time scales, which are attributed to two sub-ensembles. One of them, again, shows fast TPP dynamics (?{sub 2}-process), the other (?{sub 1}-process) displays time constants identical with those of the slow PS matrix. Upon heating the ?{sub 1}-fraction of TPP decreases until above some temperature T{sub c} only a single ?{sub 2}-population exists. Inversely, below T{sub c} a fraction of the TPP molecules is trapped by the PS matrix. At low c{sub TPP} the ?{sub 2}-relaxation does not follow frequency-temperature superposition (FTS), instead it is governed by a temperature independent distribution of activation energies leading to correlation times which follow Arrhenius laws, i.e., the ?{sub 2}-relaxation resembles a secondary process. Yet, {sup 31}P NMR demonstrates that it involves isotropic reorientations of TPP molecules within a slowly moving or rigid matrix of PS. At high c{sub TPP} the super-Arrhenius temperature dependence of ?{sub 2}(T), as well as FTS are recovered, known as typical of the glass transition in neat systems.
Kahlau, R.; Bock, D.; Schmidtke, B.; Rössler, E. A.
2014-01-01
Dielectric spectroscopy as well as 2H and 31P nuclear magnetic resonance spectroscopy (NMR) are applied to probe the component dynamics of the binary glass former tripropyl phosphate (TPP)/polystyrene (PS/PS-d3) in the full concentration (cTPP) range. In addition, depolarized light scattering and differential scanning calorimetry experiments are performed. Two glass transition temperatures are found: Tg1(cTPP) reflects PS dynamics and shows a monotonic plasticizer effect, while the lower Tg2(cTPP) exhibits a maximum and is attributed to (faster) TPP dynamics, occurring in a slowly moving or immobilized PS matrix. Dielectric spectroscopy probing solely TPP identifies two different time scales, which are attributed to two sub-ensembles. One of them, again, shows fast TPP dynamics (?2-process), the other (?1-process) displays time constants identical with those of the slow PS matrix. Upon heating the ?1-fraction of TPP decreases until above some temperature Tc only a single ?2-population exists. Inversely, below Tc a fraction of the TPP molecules is trapped by the PS matrix. At low cTPP the ?2-relaxation does not follow frequency-temperature superposition (FTS), instead it is governed by a temperature independent distribution of activation energies leading to correlation times which follow Arrhenius laws, i.e., the ?2-relaxation resembles a secondary process. Yet, 31P NMR demonstrates that it involves isotropic reorientations of TPP molecules within a slowly moving or rigid matrix of PS. At high cTPP the super-Arrhenius temperature dependence of ?2(T), as well as FTS are recovered, known as typical of the glass transition in neat systems.
Electron-positron pair production in nuclear matter - first data from HADES.
Czech Academy of Sciences Publication Activity Database
Tlustý, Pavel; Kugler, Andrej; Pleska?, Radek; Wagner, Vladimír; Suk, M.; Hlavá?, S.; Žovinec, D.
Plze? : Západo?eská universita, 2002, s. 133-149l ISBN 80-7082-907-9. [Konference ?eských a slovenských fyzik? /14./. Plze? (CZ), 09.09.2002-12.09.2002] R&D Projects: GA ?R GA202/00/1668 Keywords : electron positron pair * nuclear matter Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders
Comparative study of three-nucleon force models in nuclear matter
Logoteta, Domenico; Vidaña, Isaac; Bombaci, Ignazio; Kievsky, Alejandro
2015-06-01
We calculate the energy per particle of symmetric nuclear matter and pure neutron matter using the microscopic many-body Brueckner-Hartree-Fock (BHF) approach and employing the Argonne V18 (AV18) nucleon-nucleon (NN) potential supplemented with two different three-nucleon force models recently constructed to reproduce the binding energy of 3H,3He, and 4He nuclei as well as the neutron-deuteron doublet scattering length. We find that none of these new three-nucleon force models is able to reproduce simultaneously the empirical saturation point of symmetric nuclear matter and the properties of three- and four-nucleon systems.
Normand, A. E.; Smith, A. N.; Long, J. R.; Reddy, K. R.
2014-12-01
13C magic angle spinning (MAS) solid state Nuclear Magnetic Resonance (ssNMR) has become an essential tool for discerning the chemical composition of soil organic matter (SOM). However, the technique is limited due to the inherent insensitivity of NMR resulting in long acquisition times, especially for low carbon (C) soil. The pursuits of higher magnetic fields or concentrating C with hydrofluoric acid are limited solutions for signal improvement. Recent advances in dynamic nuclear polarization (DNP) have addressed the insensitivity of NMR. DNP utilizes the greater polarization of an unpaired electron in a given magnetic field and transfers that polarization to an NMR active nucleus of interest via microwave irradiation. Signal enhancements of up to a few orders of magnitude have been achieved for various DNP experiments. In this novel study, we conduct DNP 13C cross-polarization (CP) MAS ssNMR experiments of SOM varying in soil C content and chemical composition. DNP signal enhancements reduce the experiment run time allowing samples with low C to be analyzed in hours rather than days. We compare 13C CP MAS ssNMR of SOM with multiple magnetic field strengths, hydrofluoric acid treatment, and novel DNP approaches. We also explore DNP surface enhanced NMR Spectroscopy (SENP) to determine the surface chemistry of SOM. The presented results and future DNP MAS ssNMR advances will lead to further understanding of the nature and processes of SOM.
Non-Abelian behavior of ? bosons in cold symmetric nuclear matter
Zheng, Hua; Bonasera, Aldo
2011-05-01
The ground-state energy of infinite symmetric nuclear matter is usually described by strongly interacting nucleons obeying the Pauli exclusion principle. We can imagine a unitary transformation which groups four nonidentical nucleons (i.e., with different spin and isospin) close in coordinate space. Those nucleons, being nonidentical, do not obey the Pauli principle, thus their relative momenta are negligibly small (just to fulfill the Heisenberg principle). Such a cluster can be identified with an ? boson. But in dense nuclear matter, those ? particles still obey the Pauli principle since are constituted of fermions. The ground state energy of nuclear matter ? clusters is the same as for nucleons, thus it is degenerate. We could think of ? particles as vortices which can now braid, for instance making Be8 which leave the ground state energy unchanged. Further braiding to heavier clusters (C12, O16,…) could give a different representation of the ground state at no energy cost. In contrast d-like clusters (i.e., N=Z odd-odd nuclei, where N and Z are the neutron and proton number, respectively) cannot describe the ground state of nuclear matter and can be formed at high excitation energies (or temperatures) only. We show that even-even, N=Z, clusters could be classified as non-Abelian states of matter. As a consequence an ? condensate in nuclear matter might be hindered by the Fermi motion, while it could be possible a condensate of Be8 or heavier clusters.
Clusterized nuclear matter in the (proto-)neutron star crust and the symmetry energy
Raduta, Ad R; Gulminelli, F
2013-01-01
Though generally agreed that the symmetry energy plays a dramatic role in determining the structure of neutron stars and the evolution of core-collapsing supernovae, little is known in what concerns its value away from normal nuclear matter density and, even more important, the correct definition of this quantity in the case of unhomogeneous matter. Indeed, nuclear matter traditionally addressed by mean-field models is uniform while clusters are known to exist in the dilute baryonic matter which constitutes the main component of compact objects outer shells. In the present work we investigate the meaning of symmetry energy in the case of clusterized systems and the sensitivity of the proto-neutron star composition and equation of state to the effective interaction. To this aim an improved Nuclear Statistical Equilibrium (NSE) model is developed, where the same effective interaction is consistently used to determine the clusters and unbound particles energy functionals in the self-consistent mean-field approxi...
Intrinsic neutron background of nuclear emulsions for directional Dark Matter searches
Aleksandrov, A; Asada, T.; Buonaura, A.; L. Consiglio; D'Ambrosio, N.; De Lellis, G; Di Crescenzo, A.; Di Marco, N.; di Vacri, M. L.; Furuya, S.; Galati, G.; Gentile, V.; Katsuragawa, T.; Laubenstein, M.; Lauria, A.
2015-01-01
Recent developments of the nuclear emulsion technology led to the production of films with nanometric silver halide grains suitable to track low energy nuclear recoils with submicrometric length. This improvement opens the way to a directional Dark Matter detection, thus providing an innovative and complementary approach to the on-going WIMP searches. An important background source for these searches is represented by neutron-induced nuclear recoils that can mimic the WIMP s...
Systematic analysis of the incoming quark energy loss in cold nuclear matter
Song, Li-hua; Duan, Chun-Gui; Liu, Na,
2012-01-01
The investigation into the fast parton energy loss in cold nuclear matter is crucial for a good understanding of the parton propagation in hot-dense medium. By means of four typical sets of nuclear parton distributions and three parametrizations of quark energy loss, the parameter values in quark energy loss expressions are determined from a leading order statistical analysis of the existing experimental data on nuclear Drell-Yan differential cross section ratio as a functio...
Relativistic effects in the Bethe-Brueckner theory of nuclear matter
International Nuclear Information System (INIS)
We extend the theory of nuclear matter to include a relativistic description of nucleon motion. In particular we allow for negative energy components in the nucleon wave function. The amplitude for these components is calculated using an extended version of the one-boson-exchange model of nuclear forces. We find that the inclusion of negative energy states (pair currents) provides a strongly density dependent repulsive interaction. (If one limits oneself to a description involving positive energy states only, this interaction appears as an effective repulsive many-body force.) Our extended theory leads to major modification of the saturation properties of nuclear matter. For example, a boson-exchange force which, in a standard calculation, leads to significant overbinding of nuclear matter at much too high a saturation density yields, in our relativistic analysis, quite good agreement with the generally accepted empirical values for the binding energy and density of nuclear matter. (This potential has strong tensor coupling for the p meson and a weak tensor force. These features are favored at this time on the basis of other theoretical considerations.) We conclude that, contrary to current thought, nuclear matter should be treated as a relativistic system
In-medium effective chiral lagrangians and the pion mass in nuclear matter
International Nuclear Information System (INIS)
We argue that the effective pion mass in nuclear matter obtained from chiral effective lagrangians is unique and does not depend on off-mass-shell extensions of the pion fields as e.g. the PCAC choice. The effective pion mass in isospin symmetric nuclear matter is predicted to increase slightly with increasing nuclear density, whereas the effective time-like pion decay constant and the magnitude of the density-dependent quark condensate decrease appreciably. The in-medium Gell-Mann-Oakes-Renner relation as well as other in-medium identities are studied in addition. Finally, several constraints on effective lagrangians for the description of the pion propagation in isospin symmetric, isotropic and homogeneous nuclear matter are discussed. (orig.)
The particle-hole interaction and pion condensation in nuclear matter
International Nuclear Information System (INIS)
Following a general introduction in chapter one, the second chapter describes the calculation of the pion p-wave self-energy in nuclear matter. This quantity represents the amount of binding a pion gains by interacting with the medium. The third chapter exploits the formalism developed to work out a simple conclusion which can be drawn from the general notion of the divergence of a series of diagrams. Clearly, if the pion propagator in the medium develops a pole at some density, this implies that the one-pion-exchange NN interaction in the medium will be drastically modified. In Chapter four, the contribution to the binding energy of nuclear matter is calculated for a special set of diagrams - ring diagrams. Finally, in chapter five the low and intermediate momentum components of the nuclear matter G matrix which are relevant for nuclear structure, are studied. (Auth.)
On the Manifestation of Chiral Symmetry in Nuclei and Dense Nuclear Matter
Brown, G E; Rho, Mannque
2002-01-01
This article reviews our view on how chiral symmetry, its pattern of breaking and restoration under extreme conditions manifest themselves in the nucleon, nuclei, nuclear matter and dense hadronic matter. Topics treated are nucleon structure in terms of chiral symmetry, "first-principle" (QCD) calculations of the properties of finite nuclei effectuated by embedding the ``standard nuclear physics approach" into the framework of effective field theories of nuclei with predictions for certain astrophysical processes, a reinterpretation of the Brown-Rho (BR) scaling that implements chiral symmetry property of baryon-rich medium \\`a la "vector manifestation" of hidden local symmetry, evidences for BR scaling in nuclear processes at normal nuclear matter density and at higher density, the notion of "broadband equilibration" in heavy-ion processes, and the role of strangeness in the formation of compact stars and their collapse into black-holes. We revisit the "Cheshire-Cat phenomenon" recently revived in the form o...
Three Quark Clusters in Hot and Dense Nuclear Matter
Beyer, M; Frederico, T; Weber, H J
2002-01-01
We present a relativistic in-medium three-body equation to study correlations in hot and dense quark matter. The equation is solved for a zero-range force for parameters close to the phase transition of QCD.
Clusterized nuclear matter in the (proto-)neutron star crust and the symmetry energy
Energy Technology Data Exchange (ETDEWEB)
Raduta, A.R. [IFIN-HH, Bucharest-Magurele (Romania); Aymard, F.; Gulminelli, F. [CNRS, UMR6534, LPC, Caen (France); ENSICAEN, UMR6534, LPC, Caen (France)
2014-02-15
Though generally agreed that the symmetry energy plays a dramatic role in determining the structure of neutron stars and the evolution of core-collapsing supernovae, little is known in what concerns its value away from normal nuclear matter density and, even more important, the correct definition of this quantity in the case of unhomogeneous matter. Indeed, nuclear matter traditionally addressed by mean-field models is uniform while clusters are known to exist in the dilute baryonic matter which constitutes the main component of compact objects outer shells. In the present work we investigate the meaning of symmetry energy in the case of clusterized systems and the sensitivity of the proto-neutron star composition and equation of state to the effective interaction. To this aim an improved Nuclear Statistical Equilibrium (NSE) model is developed, where the same effective interaction is consistently used to determine the clusters and unbound particles energy functionals in the self-consistent mean-field approximation. In the same framework, in-medium modifications to the cluster energies due to the presence of the nuclear gas are evaluated. We show that the excluded volume effect does not exhaust the in-medium effects and an extra isospin and density-dependent energy shift has to be considered to consistently determine the composition of subsaturation stellar matter. The symmetry energy of diluted matter is seen to depend on the isovector properties of the effective interaction, but its behavior with density and its quantitative value are strongly modified by clusterization. (orig.)
Clusterized nuclear matter in the (proto-)neutron star crust and the symmetry energy
International Nuclear Information System (INIS)
Though generally agreed that the symmetry energy plays a dramatic role in determining the structure of neutron stars and the evolution of core-collapsing supernovae, little is known in what concerns its value away from normal nuclear matter density and, even more important, the correct definition of this quantity in the case of unhomogeneous matter. Indeed, nuclear matter traditionally addressed by mean-field models is uniform while clusters are known to exist in the dilute baryonic matter which constitutes the main component of compact objects outer shells. In the present work we investigate the meaning of symmetry energy in the case of clusterized systems and the sensitivity of the proto-neutron star composition and equation of state to the effective interaction. To this aim an improved Nuclear Statistical Equilibrium (NSE) model is developed, where the same effective interaction is consistently used to determine the clusters and unbound particles energy functionals in the self-consistent mean-field approximation. In the same framework, in-medium modifications to the cluster energies due to the presence of the nuclear gas are evaluated. We show that the excluded volume effect does not exhaust the in-medium effects and an extra isospin and density-dependent energy shift has to be considered to consistently determine the composition of subsaturation stellar matter. The symmetry energy of diluted matter is seen to depend on the isovector properties of the effective interaction, but its behavior with density and its quantitative value are strongly modified by clusterization. (orig.)
Exploring medium effects on the nuclear force
Energy Technology Data Exchange (ETDEWEB)
F. Sammarruca
2004-04-18
This STI product contains a description of results from theoretical studies in nuclear physics. The goal is a systematic investigation of the nuclear force in the nuclear medium. The problems addressed are: density-dependent effective interactions as seen through proton-nucleus reactions, nuclear matter with unequal densities of protons and neutrons, applications to asymmetric nuclei through predictions of neutron radii and neutron skins.
Non-Abelian behavior of $\\alpha$ Bosons in cold symmetric nuclear matter
Zheng, Hua
2011-01-01
The ground state energy of infinite symmetric nuclear matter is usually described by strongly interacting nucleons obeying the Pauli exclusion principle. We can imagine a unitary transformation which groups four non identical nucleons (i.e. with different spin and isospin) close in coordinate space. Those nucleons, being non identical, do not obey the Pauli principle, thus their relative momenta are negligibly small (just to fulfill the Heisenberg principle). Such a cluster can be identified with an $\\alpha$ boson. But in dense nuclear matter, those $\\alpha$ particles still obey the Pauli principle since are constituted of Fermions. The ground state energy of nuclear matter $\\alpha$ clusters is the same as for nucleons, thus it is degenerate. We could think of $\\alpha$ particles as vortices which can now braid, for instance making $^8Be$ which leave the ground state energy unchanged. Further braiding to heavier clusters ($^{12}C$, $^{16}O$..) could give a different representation of the ground state at no ene...
International Nuclear Information System (INIS)
The empirical determination of the incompressibility K? of infinite nuclear matter by means of data relative to breathing modes of the finite nuclei (isoscalar monopole resonance) resulted in controversy even in the symmetrical case, i.e. the case of equal numbers of protons and neutrons. Uncertainty is even greater in the case of nuclear matter very rich in neutrons which is found in the collapsing stellar core. In an attempt to extent the range of values of the incompressibility, K?, of symmetric nuclear matter, for which the fits to the measured breathing-mode energies are possible, we investigated generalized Skyrme-type forces with a term that is both density- and momentum-dependent. Acceptable fits are found to be possible only for values of K? in the range 215 ± 15 MeV
LOCV calculation of nuclear matter with phenomenological two-nucleon interaction operators
Energy Technology Data Exchange (ETDEWEB)
Bordbar, G.H.; Modarres, M. [Physics Department, Amir-Kabir University, Hafez Ave, Tehran (Iran, Islamic Republic of); Centre for Theoretical Physics and Mathematics, AEOI, PO Box 11365-8486, Tehran (Iran, Islamic Republic of)
1997-11-01
The lowest-order constrained variational (LOCV) method is developed for the wide range of phenomenological two-nucleon interaction operators such as V{sub 8}, V{sub 12} and UV{sub 14} potentials. The calculation is performed for both nuclear and neutron matter with the state-dependent correlation operators. The validity of our lowest-order approximation is tested by calculating the three-body cluster energy with the state-averaged correlation functions. It is shown that while the three-body cluster energy improves the nuclear matter saturation density, the LOCV method still overbinds nuclear matter with the above potentials. Finally, we find that our LOCV results are similar to those calculations which have been performed by using more sophisticated many-body techniques. (author)
Tabulated equation of state for supernova matter including full nuclear ensemble
Energy Technology Data Exchange (ETDEWEB)
Buyukcizmeci, N.; Botvina, A. S.; Mishustin, I. N. [Frankfurt Institute for Advanced Studies, J.W. Goethe University, D-60438 Frankfurt am Main (Germany)
2014-07-01
This is an introduction to the tabulated database of stellar matter properties calculated within the framework of the Statistical Model for Supernova Matter (SMSM). The tables present thermodynamical characteristics and nuclear abundances for 31 values of baryon density (10{sup –8} < ?/?{sub 0} < 0.32, ?{sub 0} = 0.15 fm{sup –3} is the normal nuclear matter density), 35 values of temperature (0.2 MeV < T < 25 MeV), and 28 values of electron-to-baryon ratio (0.02 < Y{sub e} < 0.56). The properties of stellar matter in ? equilibrium are also considered. The main ingredients of the SMSM are briefly outlined, and the data structure and content of the tables are explained.
Jet Quenching and Radiative Energy Loss in Dense Nuclear Matter
Gyulassy, Miklos; Vitev, Ivan; Wang, Xin-Nian; Zhang, Ben-Wei
2003-01-01
We review recent finite opacity approaches (GLV, WW, WOGZ) to the computation of the induced gluon radiative energy loss and their application to the tomographic studies of the density evolution in ultra-relativistic nuclear collisions.
Nuclear matter equation of state with light clusters
Ferreira, Márcio Rafael Baptista
2011-01-01
Neste projecto foi estudada a equação de estado da matéria nuclear assimétrica a baixas densidades e temperatura zero com a introdução de núcleos leves (hélio, trítio, alfa e deuterão). A equação de estado foi construída utilizando o modelo não linear de Walecka na aproximação de campo médio. Foram estudadas as propriedades da matéria nuclear para vários valores de assimetria com e sem núcleos. A dependência da densidade de dissolução de cada núcleo em função do valor das su...
The future of the nuclear industry: a matter of communication
International Nuclear Information System (INIS)
Since the very first successes achieved by the early scientists the infant nuclear industry was plagued by an atmosphere of uncertainty, conflict, anxiety and expectations. After the initial euphoria the Chernobyl accident shocked public opinion and perspectives changed. Nuclear energy is experience by the public in three dimensions. Firstly there are the technical realities of the reactor and its fantastically reduced source of power. Secondly, there is a psychological and political meaning, including the association of modern technology with authority, government, and control. The third dimension is the product of old myths about 'divine secrets', mad scientists dreadful pollution and cosmic apocalypse. To a large extent the nuclear industry is at fault for these emotional connotations. An early lapse in the communication process can be blamed for many of the misconceptions. The nuclear industry lost an opportunity by sticking to 'vagueness'. Recent trends show that a pattern of conditional acceptance is present in public opinion with regard to the nuclear industry. Possible solutions, including better communication, aggressive marketing, and the training of scientists to become communicators, are discussed. A study was done of community attitudes around Koeberg, and it is concluded that the public must be convinced of the fact that nuclear power is clean, safe, cheap and accepted as such by the industrially developed word. 62 refs., 13 figs
Nuclear Matter and its Role in Supernovae, Neutron Stars and Compact Object Binary Mergers
Lattimer, James M.; Prakash, Madappa
2000-01-01
The equation of state (EOS) of dense matter plays an important role in the supernova phenomenon, the structure of neutron stars, and in the mergers of compact objects (neutron stars and black holes). During the collapse phase of a supernova, the EOS at subnuclear densities controls the collapse rate, the amount of deleptonization and thus the size of the collapsing core and the bounce density. Properties of nuclear matter that are especially crucial are the symmetry energy a...
Relativistic mean-field parametrization of effective interaction in nuclear matter
Energy Technology Data Exchange (ETDEWEB)
Gmuca, S. (Slovenska Akademia Vied, Bratislava (Czechoslovakia). Fyzikalny Ustav)
1992-06-01
The results of the modern relativistic Dirac-Brueckner calculations of nuclear matter are parametrized in terms of the relativistic {sigma}-{omega} mean-field theory with scalar and vector nonlinear selfinteractions. It is shown that the inclusion of the isoscalar vector-meson quartic selfinteraction is essential for obtaining a proper density dependence of the vector potential in the mean-field model. The obtained mean-field parameters represent a simple parametrization of effective interaction in nuclear matter. This interaction may be used in the mean-field studies of the structure of finite nuclei without the introduction of additional free parameters. (orig.).
Relativistic mean-field parametrization of effective interaction in nuclear matter
International Nuclear Information System (INIS)
The results of the modern relativistic Dirac-Brueckner calculations of nuclear matter are parametrized in terms of the relativistic ?-? mean-field theory with scalar and vector nonlinear selfinteractions. It is shown that the inclusion of the isoscalar vector-meson quartic selfinteraction is essential for obtaining a proper density dependence of the vector potential in the mean-field model. The obtained mean-field parameters represent a simple parametrization of effective interaction in nuclear matter. This interaction may be used in the mean-field studies of the structure of finite nuclei without the introduction of additional free parameters. (orig.)
Quasi-particle interaction in nuclear matter from chiral pion-nucleon dynamics
Kaiser, N
2006-01-01
Based on a recent chiral approach to nuclear matter we calculate the in-medium interaction of nucleons at the Fermi surface $|\\vec p_{1,2}|=k_f$. The isotropic part of this quasi-particle interaction is characterized by four density dependent (dimensionful) Fermi-liquid parameters: $f_0(k_f), f_0'(k_f), g_0(k_f)$ and $g_0'(k_f)$. In the approximation to $1\\pi$-exchange and iterated $1\\pi$-exchange (which as such leads already to a good nuclear matter equation of state) we fi...
Vacuum Effects and Compressional Properties of Nuclear Matter in Cutoff Field Theory
Kouno, H; Iwasaki, Y; Noda, N; Mitsumori, T; Koide, K; Hasegawa, A; Nakano, M; Kouno, Hiroaki; Sakamoto, Katsuaki; Iwasaki, Yoshitaka; Noda, Nobuo; Mitsumori, Tomohiro; Koide, Kazuharu; Hasegawa, Akira; Nakano, Masahiro
1997-01-01
Including the vacuum effects, the compressional properties of nuclear matter are studied in the cutoff field theory. Under the Hartree approximation, the low-energy effective Lagrangian is derived in the framework of the renormalization group methods. The coefficients are determined in a way where the physical results hardly depend on the value of the cutoff which is conveniently introduced into the theory. It is shown that, to reproduce the empirical data of the nucleus incompressibility, the compressibility of the nuclear matter is favorable to be 250$\\sim$350MeV.
The equation of state for the nuclear matter and the properties of the neutron star
Liu, Chang-Geng; Sun, Bao-Xi
2007-01-01
The equation of state for the beta stable nuclear matter is calculated numerically, and then the Tolman-Oppenheimer-Volkov equation for the structure of the neutron star is solved in the fourth-order Runge-Kutta algorithm. It shows the mass and radius of the neutron star are functions of the central density of the neutron star and a maximum mass of 1.932 solar masses with a corresponding radius of 9.340km is obtained. Considering the equation of state of the nuclear matter m...
International Nuclear Information System (INIS)
The Debye screening masses of the ?, ? and neutral ? mesons and the photon are calculated in the relativistic mean-field approximation. As the density of the nucleon increases, all the screening masses of mesons increase. A different result with Brown–Rho scaling is shown, which implies a reduction in the mass of all the mesons in the nuclear matter, except the pion. Replacing the masses of the mesons with their corresponding screening masses in the Walecka-1 model, five saturation properties of the nuclear matter are fixed reasonably, and then a density-dependent relativistic mean-field model is proposed without introducing the nonlinear self-coupling terms of mesons. (author)
Scientific Electronic Library Online (English)
A., Delfino; M., Malheiro; T., Frederico.
2001-09-01
Full Text Available The link between non-linear chiral effective Lagrangians and the Walecka model description of bulk nuclear matter is questioned. This fact is by itself due to the Mean Field Approximation (MFA) which innuclear mater makes the picture of a nucleon-nucleon interaction based on scalar (vector) meson ex [...] change equivalent to the description of a nuclear matter based on attractive and repulsive contact interactions. We present a linear chiral model where this link between the Walecka model and an underlying to chiral symmetry realization still holds, due to MFA.
BCS-BEC crossover and liquid-gas phase transition in nuclear matter
Energy Technology Data Exchange (ETDEWEB)
Jin Meng [Institute of Particle Physics and Physical Department, Central China Normal University, Wuhan 4300079 (China); Urban, Michael [Groupe de Physique Theorique, Institut de Physique Nucleaire -Centre Scientifique d' Orsay, F-91406 Orsay (France); Schuck, Peter, E-mail: jinm@iopp.ccnu.edu.cn [Laboratoire de Physique et Modelisation des Milieux Condenses,CNRS and Universite Joseph Fourier, BP 166, 38042 Grenoble Cedex (France)
2011-09-16
The effect of nucleon-nucleon correlations in symmetric nuclear matter at finite temperature is studied beyond BCS theory. We calculate the critical temperature for a BEC superfluid of deuterons, of a BCS superfluid of nucleons, and in the crossover between these limits. The effect of the correlations on the liquid-gas phase transition is discussed. Our results show that nucleon-nucleon correlations beyond BCS play an important role for the properties of nuclear matter, especially in the low-density region.
A possible determination of the quark radiation length in cold nuclear matter
International Nuclear Information System (INIS)
We calculate the differential Drell-Yan production cross section in proton-nucleus collisions by including both next-to-leading order perturbative effects and effects of the nuclear medium. We demonstrate that dilepton production in fixed target experiments is an excellent tool to study initial-state parton energy loss in large nuclei and to accurately determine the stopping power of cold nuclear matter. We provide theoretical predictions for the attenuation of the Drell-Yan cross section at large values of Feynman xF and show that for low proton beam energies experimental measurements at Fermilab's E906 can clearly distinguish between nuclear shadowing and energy loss effects. If confirmed by data, our results may help determine the quark radiation length in cold nuclear matter X0?10-13 m.
Cluster Formation and The Virial Equation of State of Low-Density Nuclear Matter
Horowitz, C J
2006-01-01
We present the virial equation of state of low-density nuclear matter composed of neutrons, protons and alpha particles. The virial equation of state is model-independent, and therefore sets a benchmark for all nuclear equations of state at low densities. We calculate the second virial coefficients for nucleon-nucleon, nucleon-alpha and alpha-alpha interactions directly from the relevant binding energies and scattering phase shifts. The virial approach systematically takes into account contributions from bound nuclei and the resonant continuum, and consequently provides a framework to include strong-interaction corrections to nuclear statistical equilibrium models. The virial coefficients are used to make model-independent predictions for a variety of properties of nuclear matter over a range of densities, temperatures and compositions. Our results provide important constraints on the physics of the neutrinosphere in supernovae. The resulting alpha particle concentration differs from all equations of state cu...
Investigation of compressed and highly excited nuclear matter in relativistic heavy ion collisions
International Nuclear Information System (INIS)
The gross properties of nuclear matter at high densities and temperatures and the significance of the nuclear equation of state for high energy nuclear collisions are investigated within the nuclear fluid dynamical model. The hydrdynamical description and the properties of the nuclear fluid are extensively discussed. It is shown that at bombarding energies of 1-4 GeV/n compressions of 3-6 psub(o) and temperatures T approx. 100 MeV can be reached. At medium energies we compare the nuclear fluid dynamical model and the time-dependent Hartree-Fock model. The importance of isobaric resonance - and pion production at higher energies is discussed, which for an exponentially increasing hadronic mass spectrum leads to a limiting temperature Tsup(Max). (orig.)
Properties of charmed and bottom hadrons in nuclear matter A plausible study
Tsushima, K
2003-01-01
Changes in properties of heavy hadrons with a charm or a bottom quark are studied in nuclear matter. Effective masses (scalar potentials) for the hadrons are calculated using quark-meson coupling model. Our results also suggest that the heavy baryons containing a charm or a bottom quark will form charmed or bottom hypernuclei, which was first predicted in mid 70's. In addition a possibility of $B^-$-nuclear bound (atomic) states is briefly discussed.
Nuclear matter and neutron-star properties calculated with the Skyrme interaction
Stone, JR; Miller, JC; Koncewicz, R; Stevenson, PD; Strayer, MR
2003-01-01
The effective Skyrme interaction has been used extensively in mean-field models for several decades and many different parametrizations of the interaction have been proposed. All of these give similar agreement with the experimental observables of nuclear ground states as well as with the properties of infinite symmetric nuclear matter at the saturation density n 0. However, when applied over a wider range of densities (up to ?3n0) they predict widely varying behavior for the observables of b...
Nuclear uncertainties in the spin-dependent structure functions for direct dark matter detection
Cerdeno, David G; Fornasa, Mattia; Huh, Ji-Haeng; Peiro, Miguel
2012-01-01
We study the effect that uncertainties in the nuclear spin-dependent structure functions have in the determination of the dark matter (DM) parameters in a direct detection experiment. We show that different nuclear models that describe the spin-dependent structure function of specific target nuclei can lead to variations in the reconstructed values of the DM mass and scattering cross-section. We propose a parametrization of the spin structure functions that allows us to trea...
Wigner-Kirkwood expansion of the phase-space density for half infinite nuclear matter
International Nuclear Information System (INIS)
The phase space distribution of half infinite nuclear matter is expanded in a ?-series analogous to the low temperature expansion of the Fermi function. Besides the usual Wigner-Kirkwood expansion, oscillatory terms are derived. In the case of a Woods-Saxon potential, a smallness parameter is defined, which determines the convergence of the series and explains the very rapid convergence of the Wigner-Kirkwood expansion for average (nuclear) binding energies
Probing the Nuclear Symmetry Energy with Heavy-Ion Reactions Induced by Neutron-Rich Nuclei
Chen, Lie-Wen; Ko, Che Ming; Li, Bao-An; Yong, Gao-Chan
2007-01-01
Heavy-ion reactions induced by neutron-rich nuclei provide a unique means to investigate the equation of state of isospin-asymmetric nuclear matter, especially the density dependence of the nuclear symmetry energy. In particular, recent analyses of the isospin diffusion data in heavy-ion reactions have already put a stringent constraint on the nuclear symmetry energy around the nuclear matter saturation density. We review this exciting result and discuss its implications on ...
Liquid-gas phase transition in nuclear matter including strangeness
International Nuclear Information System (INIS)
We apply the chiral SU(3) quark mean field model to study the properties of strange hadronic matter at finite temperature. The liquid-gas phase transition is studied as a function of the strangeness fraction. The pressure of the system cannot remain constant during the phase transition, since there are two independent conserved charges (baryon and strangeness number). In a range of temperatures around 15 MeV (precise values depending on the model used) the equation of state exhibits multiple bifurcates. The difference in the strangeness fraction fs between the liquid and gas phases is small when they coexist. The critical temperature of strange matter turns out to be a nontrivial function of the strangeness fraction
Shear viscosity of $\\beta$-stable nuclear matter
Benhar, Omar; Carbone, Arianna
2009-01-01
Viscosity plays a critical role in determining the stability of rotating neutron stars. We report the results of a calculation of the shear viscosity of $\\beta$~-~stable matter, carried out using an effective interaction based on a state-of-the-art nucleon-nucleon potential and the formalism of correlated basis functions. Within our approach the equation of state, determining the proton fraction, and the nucleon-nucleon scattering probability are consistently obtained from t...
Fermionic condensation in ultracold atoms, nuclear matter and neutron stars
Salasnich, Luca
2013-01-01
We investigate the Bose-Einstein condensation of fermionic pairs in three different superfluid systems: ultracold and dilute atomic gases, bulk neutron matter, and neutron stars. In the case of dilute gases made of fermionic atoms the average distance between atoms is much larger than the effective radius of the inter-atomic potential. Here the condensation of fermionic pairs is analyzed as a function of the s-wave scattering length, which can be tuned in experiments by usin...
International Nuclear Information System (INIS)
The properties of nuclear matter are studied in the cutoff field theory. It is indicated that the properties of nuclear matter are somewhat different from those described by the ordinary renormalization procedures when the cutoff is small (5 and ?6-terms seem to be needed in the effective Lagrangian of the cutoff field theory in the Hartree approximation. (author)
Halftime - a balance in matters nuclear of the grand coalition
International Nuclear Information System (INIS)
On November 11, 2005, the coalition partners, CDU/CSU and SPD, signed the agreement establishing a coalition in the German federal parliament under the heading of ''Together for Germany''. Among other things, this raised the question of what would happen in the fields of energy policy and nuclear power. After 2 years of a grand coalition, it is time to draw some interim conclusions. The coalition agreement contains statements to the effect that energy policy means fundamental economic, structural and climate policies, and that secure, low-cost, non-polluting energy supplies are elementary prerequisites of a modern, capable national economy. A sustainable overall energy policy concept should be based on a balanced energy mix. This overall concept, one of the results of ''energy summit'' talks with Federal Chancellor Merkel, was announced for the end of 2007. The 3 energy summit discussions with Federal Chancellor Merkel deliberately avoided the subject of nuclear power. There is no debate about the implications of nuclear energy. This in no way improved the status of nuclear power in Germany. What remains is hope for the second half of this government's term of office. The beginning of that term is marked by the McKinsey study, initiated by the Federation of German Industries (BDI), on ''Cost and Potential of Avoiding Greenhouse Gas Emissions in Germany,'' which says that operating German nuclear power plants for 60 or even 45 years would result in a CO2 avoidance poteyears would result in a CO2 avoidance potential for 2020 which would be approximately 90 million tons higher, and in avoidance costs lower by 4.5 billion euro per year. (orig.)
Nuclear matter at high density: Phase transitions, multiquark states, and supernova outbursts
Krivoruchenko, M I; Rasinkova, T L; Simonov, Yu A; Trusov, M A; Yudin, A V
2010-01-01
Phase transition from hadronic matter to quark-gluon matter is discussed for various regimes of temperature and baryon number density. For small and medium densities, the phase transition is accurately described in the framework of the Field Correlation Method, whereas at high density predictions are less certain and leave room for the phenomenological models. We study formation of multiquark states (MQS) at zero temperature and high density. Relevant MQS components of the nuclear matter can be described using a previously developed formalism of the quark compound bags (QCB). Partial-wave analysis of nucleon-nucleon scattering indicates the existence of 6QS which manifest themselves as poles of $P$-matrix. In the framework of the QCB model, we formulate a self-consistent system of coupled equations for the nucleon and 6QS propagators in nuclear matter and the G-matrix. The approach provides a link between high-density nuclear matter with the MQS components and the cumulative effect observed in reactions on th...
Finite Temperature Study of Nuclear Matter in SU(2) Chiral Sigma Model
Jena, P K
2003-01-01
We study here the equation of state of symmetric nuclear matter at finite temperatures using a modified SU(2) Chiral Sigma model. The effect of temperature on effective mass, entropy and binding energy is also studied. The liquid-gas phase transition is investigated and the critical values of temperature, density and pressure are calculated.
Cold Nuclear Matter Effects on Open and Hidden Heavy Flavor Production at the LHC
Vogt, R
2015-01-01
We discuss a number of cold nuclear matter effects that can modify open heavy flavor and quarkonium production in proton-nucleus collisions and could thus also affect their production in nucleus-nucleus collisions, in addition to hot quark-gluon plasma production. We show some results for $p+$Pb collisions at sqrt s = 5 TeV at the LHC.
Shell effects in hot nuclei and their influence on nuclear composition in supernova matter
Energy Technology Data Exchange (ETDEWEB)
Nishimura, Suguru [Department of Pure and Applied Physics, Waseda University, 3-4-1 Okubo Shinjuku-ku, Tokyo 169-8555 (Japan); Takano, Masatoshi [Department of Pure and Applied Physics, Waseda University, 3-4-1 Okubo Shinjuku-ku, Tokyo 169-8555, Japan and Research Institute for Science and Engineering, Waseda University, 3-4-1 Okubo Shinjuku-ku, Tokyo 169-8555 (Japan)
2014-05-02
We calculate nuclear composition in supernova (SN) matter explicitly taking into account the temperature dependence of nuclear shell effects. The abundance of nuclei in SN matter is important in the dynamics of core-collapse supernovae and, in recently constructed equations of state (EOS) for SN matter, the composition of nuclei are calculated assuming nuclear statistical equilibrium wherein the nuclear internal free energies govern the composition. However, in these EOS, thermal effects on the shell energy are not explicitly taken into account. To address this shortfall, we calculate herein the shell energies of hot nuclei and examine their influence on the composition of SN matter. Following a simplified macroscopic-microscopic approach, we first calculate single-particle (SP) energies by using a spherical Woods-Saxon potential. Then we extract shell energies at finite temperatures using Strutinsky method with the Fermi distribution as the average occupation probability of the SP levels. The results show that at relatively low temperatures, shell effects are still important and magic nuclei are abundant. However, at temperatures above approximately 2 MeV, shell effects are almost negligible, and the mass fractions with shell energies including the thermal effect are close to those obtained from a simple liquid drop model at finite temperatures.
BIGDELI, M.; Bordbar, G. H.; Rezaei, Z.
2009-01-01
In this paper we study the magnetic susceptibility and other thermodynamic properties of the polarized nuclear matter at finite temperature using the lowest order constrained variational (LOCV) method employing the $AV_{18}$ potential. Our results show a monotonic behavior for the magnetic susceptibility which indicates that the spontaneous transition to the ferromagnetic phase does not occur for this system.
Heavy-quark expansion for D and B mesons in nuclear matter
Directory of Open Access Journals (Sweden)
Buchheim Thomas
2014-01-01
Full Text Available The planned experiments at FAIR enable the study of medium modifications of D and B mesons in (dense nuclear matter. Evaluating QCD sum rules as a theoretical prerequisite for such investigations encounters heavy-light four-quark condensates. We utilize an extended heavy-quark expansion to cope with the condensation of heavy quarks.
Relativistic many-body studies of nuclear matter at finite temperature
International Nuclear Information System (INIS)
The properties of nuclear matter are studied as a function of temperature and density. The model employed for nuclear matter is a relativistic quantum field theory in which nucleons interact with massive scalar mesons and massive vector mesons. The techniques of quantum statistical mechanics, particularly those based on the use of Green's functions, are used to extract physical information from this field theory. The equation of state for nuclear matter in equilibrium is calculated at finite temperature in a mean-field approximation, including the effects of a quantum correction not previously accounted for at finite temperature. Consideration of corrections to this equation of state indicates that this mean-field description is valid for any temperature, provided only that the density is sufficiently high. A study is also made of the thermal conductivity of nuclear matter. A fully relativistic expression is found in linear response theory for the low-temperature thermal conductivity based on one-pion exchange. This expression is inversely proportional to the temperature and approximately proportional to the number density of nucleons at high density. The formalism in which this is calculated allows the correct expression for the thermal conductivity in the high-temperature classical limit to be recovered. The aforementioned density and temperature dependences of the low-temperature, high-density thermal conductivity is found to be unaffected by including the effects of additional meson exchanges
Heavy-quark expansion for D and B mesons in nuclear matter
Buchheim, Thomas; Kampfer, Burkhard
2014-01-01
The planned experiments at FAIR enable the study of medium modifications of $D$ and $B$ mesons in (dense) nuclear matter. Evaluating QCD sum rules as a theoretical prerequisite for such investigations encounters heavy-light four-quark condensates. We utilize an extended heavy-quark expansion to cope with the condensation of heavy quarks.
Statistical abrasion of nucleons from realistic nuclear-matter distributions
International Nuclear Information System (INIS)
A description of peripheral nuclear collisions at high energies in terms of quasi-free nucleon-nucleon collisions is proposed. The statistical removal of nucleons from diffuse nuclear-density distributions is formulated in the framework of the abrasion model. Based on the nucleon-nucleon cross sections, energy-dependent partial and total abrasion cross sections are obtained. The total abrasion cross section is found to be equivalent to the total interaction cross section resulting from a microscopic Glauber-type calculation. In contrast to geometrical and optical abrasion models, the statistical abrasion formalism describes the fluctuations of the prefragment neutron-to-proton ratio without need for further assumptions. The predictions of the statistical abrasion model are compared to experimental data. (orig.)
Thermal fluctuations of the pion field and ?-condensation in nuclear matter
International Nuclear Information System (INIS)
The ?-meson field in isotopically-symmetrical nuclear matter is investigated for non-zero temperature T and high density rho, for that the pion degree of freedom softening occurs and the ?-condensation instability appearance is possible. The model is advanced describing the pion field thermal fluctuations near the ?-condensation critical point. It is shown that these fluctuations availability determines the main, principal features of the whole physical picture. The commonly up to now used criterion of the ?-condensation, as the second kind phase transition, is not suitable: the equation G-1(?, k vector, rho, T)=0 has, by no means, the solution ?2(k vector, rho, T)<0. (G is the ?-meson propagator in nuclear matter). The availability of the minimum of the thermodynamic potential min?<0 at non-zero condensate field phi vectorsup(a) is the condition of the ?-condensation. The 1- or 2-kind phase transition is possible depending of the ??-interaction sort in matter
International Nuclear Information System (INIS)
The effect of the exchange terms in nucleon-nucleon interaction is studied for nuclear matter and neutron matter in the framework of the hybrid derivative coupling model. Pseudovector coupling between the pion and the nucleon and both vector and tensor couplings between the rho-meson and the nucleon have been included. A reduced value of the effective nucleon mass is obtained in nuclear matter as a result of the inclusion of the exchange terms. The rho-meson coupling constant obtained from meson exchange theories can be used to get a reasonable value of symmetry energy. The maximum limit of the neutron star mass obtained in this work is more than twice the solar mass. This rather high limit points to the inadequacy of the present Lagrangian at such a high density as it is restricted only to nucleonic degrees of freedom. (author)
Remarks on a determination of the nuclear matter caloric curve
International Nuclear Information System (INIS)
The recent publication of a nuclear caloric curve is examined. We study the influence of the excited states of the fragments on the extracted temperatures, the freeze-out density and interpretation of the observed steady rise of the temperature at high excitation energies. A deeper understanding of this curve is necessary before a definite conclusion can be drawn about the observation of a liquid-gas phase transition. (authors)
Six-quark clusters in nuclear matter at low temperatures
International Nuclear Information System (INIS)
The two-phase system consisting of nucleons and six-quark clusters is investigated. The interaction between nucleons and six-quarks is represented by a sum of the fermi and Yukawa potentials. The temperature behaviour of nucleon and six-quark concentrations versus density is found. It is shown that with a normal nuclear density, six-quark clusters may amount to about 10%, which is in agreement with experiment
Intrinsic neutron background of nuclear emulsions for directional Dark Matter searches
Aleksandrov, A; Buonaura, A; Consiglio, L; D'Ambrosio, N; De Lellis, G; Di Crescenzo, A; Di Marco, N; Di Vacri, M L; Furuya, S; Galati, G; Gentile, V; Katsuragawa, T; Laubenstein, M; Lauria, A; Loverre, P F; Machii, S; Monacelli, P; Montesi, M C; Naka, T; Pupilli, F; Rosa, G; Sato, O; Tioukov, V; Umemoto, A; Yoshimoto, M
2015-01-01
Recent developments of the nuclear emulsion technology led to the production of films with nanometric silver halide grains suitable to track low energy nuclear recoils with submicrometric length. This improvement opens the way to a directional Dark Matter detection, thus providing an innovative and complementary approach to the on-going WIMP searches. An important background source for these searches is represented by neutron-induced nuclear recoils that can mimic the WIMP signal. In this paper we provide an estimation of the contribution to this background from the intrinsic radioactive contamination of nuclear emulsions. We also report the induced background as a function of the read-out threshold, by using a GEANT4 simulation of the nuclear emulsion, showing that it amounts to about 0.02 neutrons per year per kilogram, fully compatible with the design of a 10 kg$\\times$year exposure.
International Nuclear Information System (INIS)
Chiral theories with spontaneous symmetry breaking such as the Nambu-Jona-Lasinio (NJL) model lead to the existence of a scalar mode. We present in a detailed manner how the corresponding low-momentum effective Lagrangian involving the scalar field can be constructed starting from the NJL model. We discuss the relevance of the scalar mode for the problem of nuclear binding and saturation. We show that it depends on the nucleon mass origin with two extreme cases. If this origin is entirely due to confinement, the coupling of this mode to the nucleons vanishes, making it irrelevant for the nuclear binding problem. If instead it is entirely due to spontaneous symmetry breaking, it couples to the nucleons but nuclear matter collapses. It is only in the case of a mixed origin with spontaneous breaking that nuclear matter can be stable and reach saturation. We describe models of nucleon structure where this balance is achieved. We also show how chiral constraints and confinement modify the QCD sum rules for mass evolution in nuclear matter.
Study of Cold Nuclear Matter Effects on Heavy Quarkonia in Proton-Lead Collisions at LHCb
Jing, Fanfan; Yang, Zhenwei; Schmidt, Burkhard
Proton-nucleus ($p\\rm{A}$) collisions play an important role in high energy nuclear physics as they allow to study nuclear matter effects and the parton distribution functions in the nuclear environment (nPDF). The quantum chromodynamics (QCD) phase transition from hadron gas to the the quark-gluon plasma (QGP) is not expected to occur in a $p\\rm{A}$ collision due to its limited space-time size. Therefore, the $p\\rm{A}$ collisions provide an ideal platform to study cold nuclear matter (CNM) effects, which are also known as normal nuclear matter effects. The measurements of the productions and correlations of the final-state particles in $p\\rm{A}$ collisions serve the purpose to test various theoretical models for CNM effects, to constrain the benchmarking nPDFs, and thus provide a baseline to understand and interpret the QGP created in ultra-relativistic heavy-ion collisions. Heavy quarkonia (including charmonia and bottomonia), which are produced at the early stage of heavy-ion collisions, are considered goo...
Cold Nuclear Matter Effects on J/psi Production: Intrinsic and Extrinsic Transverse Momentum Effects
Energy Technology Data Exchange (ETDEWEB)
Ferreiro, E.G.; /Santiago de Compostela U.; Fleuret, F.; /Ecole Polytechnique; Lansberg, J.P.; /Heidelberg U.; Rakotozafindrabe, A.; /SPhN, DAPNIA, Saclay
2010-08-26
Cold nuclear matter effects on J/{psi} production in proton-nucleus and nucleus-nucleus collisions are evaluated taking into account the specific J/{psi}-production kinematics at the partonic level, the shadowing of the initial parton distributions and the absorption in the nuclear matter. We consider two different parton processes for the c{bar c}-pair production: one with collinear gluons and a recoiling gluon in the final state and the other with initial gluons carrying intrinsic transverse momentum. Our results are compared to RHIC observables. The smaller values of the nuclear modification factor R{sub AA} in the forward rapidity region (with respect to the mid rapidity region) are partially explained, therefore potentially reducing the need for recombination effects.
Symmetry energy softening in nuclear matter with non-nucleonic constituents
Jiang, Wei-Zhou; Zhang, Dong-Rui
2012-01-01
We study the trend of the nuclear symmetry energy in relativistic mean-field models with appearance of the hyperon and quark degrees of freedom at high densities. On the pure hadron level, we focus on the role of $\\Lambda$ hyperons in influencing the symmetry energy both at given fractions and at charge and chemical equilibriums. The softening of the nuclear symmetry energy is observed with the inclusion of the $\\Lambda$ hyperons that suppresses the nucleon fraction. In the phase with the admixture of quarks and hadrons, the equation of state is established on the Gibbs conditions. With the increase of the quark volume fraction in denser and denser matter, the apparent nuclear symmetry energy decreases till to disappear. This softening would have associations with the observations which need detailed discriminations in dense matter with the admixture of new degrees of freedom created by heavy-ion collisions.
Open charm tomography of cold and hot nuclear matter
Scientific Electronic Library Online (English)
Ivan, Vitev.
2007-06-01
Full Text Available We identify the nuclear effects that modify the cross sections for open heavy flavor production in proton-nucleus and nucleus-nucleus collisions. In p+A reactions, we calculate and resum the coherent nuclear-enhanced power corrections from the final-state parton scattering in the medium. We find tha [...] t single and double inclusive open charm production can be suppressed as much as the yield of neutral pions from dynamical high-twist shadowing. Effects of energy loss in p+A collisions are also investigated. These lead to significantly weaker transverse momentum dependence of the nuclear attenuation and give a sizable contribution to the forward rapidity hadron suppression. In A+A reactions we revisit the question of the measured large heavy flavor quenching at RHIC. We derive the collisional broadening of the heavy meson's transverse momentum and the distortion of its intrinsic light cone wave function. The medium-induced dissociation probability of heavy mesons is shown to be sensitive to the opacity of the quark-gluon plasma and the time dependence of its formation and evolution. In contrast to previous results on heavy quark modification, our approach predicts suppression of B-mesons comparable to that of D-mesons at transverse momenta as low as pT ~ 10 GeV. It allows for an improved description of the large attenuation of non-photonic electrons in central Au+Au reactions at RHIC. Preliminary results in the implementation of collisional and radiative energy loss in a Langevin simulation approach to heavy quark diffusion and attenuation are also presented.
Deuteron formation in nuclear matter within the Faddeev approach
Beyer, M; Röpke, G
1999-01-01
We consider deuteron formation in heavy ion collisions at intermediate energies. The elementary reaction rates (Nd -> NNN) in this context are calculated using rigorous Faddeev methods. To this end an in-medium Faddeev equation that consistently includes the energy shift and Pauli blocking effects has been derived and solved numerically. As a first application we have calculated the life-time of deuteron fluctuations for nuclear densities and temperatures typical for the final stage of heavy ion collisions. We find substantial differences between using the isolated and the in-medium rates.
From condensed matter to nuclear and atomic physics, by way of the stars
Baym, Gordon
2004-03-01
Neutron stars have been a remarkable setting for problems of condensed matter physics off the beaten track. In this talk I will review intersections of condensed matter and nuclear physics in neutron star interiors, e.g., neutron and proton superfluidity; the sudden speedups of pulsars (glitches) and their relation to pinning and unpinning of vortices to nuclei in the stellar crusts; unusual ``pasta" phases of nuclei; and attempts to understand matter at densities beyond the density of matter inside normal nuclei, where one begins possibly to encounter Bose-Einstein condensates of ? and K mesons, as well as quark matter, both normal and superconducting. I will also describe how trying to understand the physics of matter under extreme conditions of pressure and density has led to insights into condensed matter physics in more familiar settings, e.g., from possible Tkachenko modes of the vortices in the neutron superfluids, to the hydrodynamics of rotating superfluid ^4He, to Tkachenko modes in trapped atomic Bose-Einstein condensates.
Jet tomography of hot and cold nuclear matter
International Nuclear Information System (INIS)
Modification of parton fragmentation functions by multiple scattering and gluon bremsstrahlung in nuclear media is shown to describe very well the recent HERMES data in deeply inelastic scattering, giving the first evidence of the A2/3 dependence of the modification. The energy loss is found to be ?0.5 GeV/fm for a 10-GeV quark in an Au nucleus. Including the effect of expansion, analysis of the ?0 spectra in central Au+Au collisions at ?(s)=130 GeV yields an averaged energy loss equivalent to ?7.3 GeV/fm in a static medium. Predictions for central Au+Au collisions at ?(s)=200 GeV are also given
Onset of nuclear matter expansion in Au+Au collisions
Crochet, Philippe; Gobbi, A; Donà, R; Coffin, J P; Fintz, P; Guillaume, G; Jundt, F; Kühn, C E; Roy, C; De Schauenburg, B; Tizniti, L; Wagner, P; Alard, J P; Amouroux, V; Andronic, A; Basrak, Z; Bastid, N; Belyaev, I; Best, D; Biegansky, J; Butà, A; Caplar, R; Cindro, N; Dupieux, P; Dzelalija, M; Fan, Z G; Fodor, Z; Fraysse, L; Freifelder, R P; Herrmann, N; Hildenbrand, K D; Hong, B H; Jeong, S C; Kecskeméti, J; Kirejczyk, M; Koncz, P; Korolija, M; Kotte, R; Lebedev, A; Leifels, Y; Man'ko, V I; Moisa, D; Mösner, J; Neubert, W; Pelte, D; Petrovici, M; Pinkenburg, C H; Pras, P; Ramillien, V; Reisdorf, W; Ritman, J L; Sadchikov, A G; Schüll, D; Seres, Z; Sikora, B; Simion, V; Siwek-Wilczynska, K; Sodan, U; Teh, K M; Trzaska, M; Vasilev, M A; Wang, G S; Wessels, J P; Wienold, T; Wisniewski, K; Wohlfarth, D; Zhilin, A V
1997-01-01
Using the FOPI detector at GSI Darmstadt, excitation functions of collective flow components were measured for the Au+Au system, in the reaction plane and out of this plane, at seven incident energies ranging from 100AMeV to 800AMeV. The threshold energies, corresponding to the onset of sideward-flow (balance energy) and squeeze-out effect (transition energy), are extracted from extrapolations of these excitation functions toward lower beam energies for charged products with Z>2. The transition energy is found to be larger than the balance energy. The impact parameter dependence of both balance and transition energies, when extrapolated to central collisions, suggests comparable although slightly higher values than the threshold energy for the radial flow. The relevant parameter seems to be the energy deposited into the system in order to overcome the attractive nuclear forces.
Investigating Biological Matter with Theoretical Nuclear Physics Methods
Faccioli, Pietro
2011-01-01
The internal dynamics of strongly interacting systems and that of biomolecules such as proteins display several important analogies, despite the huge difference in their characteristic energy and length scales. For example, in all such systems, collective excitations, cooperative transitions and phase transitions emerge as the result of the interplay of strong correlations with quantum or thermal fluctuations. In view of such an observation, some theoretical methods initially developed in the context of theoretical nuclear physics have been adapted to investigate the dynamics of biomolecules. In this talk, we review some of our recent studies performed along this direction. In particular, we discuss how the path integral formulation of the molecular dynamics allows to overcome some of the long-standing problems and limitations which emerge when simulating the protein folding dynamics at the atomistic level of detail.
Explicit energy functional for infinite nuclear matter with the tensor force
International Nuclear Information System (INIS)
We have applied the variational method using explicit energy functionals (EEFs) to energy calculations of infinite nuclear matter. In EEFs, the energy per nucleon is explicitly expressed with spin-isospin-dependent two-body distribution functions, which are regarded as variational functions, and fully minimized energies are conveniently calculated with the EEF. A remarkable feature of this approach is that EEFs guarantee non-negativeness of structure functions. In this study, we extend the EEF variational method so as to consider state- independent three-body forces for neutron matter at finite temperatures following the procedure proposed by Schmidt and Pandharipande. For neutron matter, the free energies obtained with the Argonne v4' two-body potential and the repulsive part of the Urbana IX (UIX) three- body potential are quite reasonable. Furthermore, we improve the EEF of nuclear matter using the two-body central and tensor forces by considering the main three-body cluster terms and guaranteeing non-negativeness of tensor structure functions. In addition, healing distances are introduced for two-body distribution functions so that Mayer's condition is satisfied. The obtained energies per neutron of neutron matter with the Argonne v6' two-body potential and the repulsive part of the UIX potential are in good agreement with those obtained by auxiliary field diffusion Monte Carlo calculations.
SIGNATURES OF DARK MATTER BURNING IN NUCLEAR STAR CLUSTERS
International Nuclear Information System (INIS)
In order to characterize how dark matter (DM) annihilation inside stars changes the aspect of a stellar cluster, we computed the evolution until the ignition of the He burning of stars from 0.7 Msun to 3.5 Msun within halos of DM with different characteristics. We found that, when a cluster is surrounded by a dense DM halo, the positions of the cluster' stars in the H-R diagram have a brighter and hotter turnoff point than in the classical scenario without DM, therefore giving the cluster a younger appearance. The high DM densities required to produce these effects are expected only in very specific locations, such as near the center of our Galaxy. In particular, if DM is formed by the 8 GeV weakly interacting massive particles recently invoked to reconcile the results from direct detection experiments, then this signature is predicted for halos of DM with a density ?? = 3 x 105 GeV cm-3. A DM density gradient inside the stellar cluster would result in a broader main sequence, turnoff, and red giant branch regions. Moreover, we found that for very high DM halo densities the bottom of the isochrones in the H-R diagram rises to higher luminosities, leading to a characteristic signature on the stellar cluster. We argue that this signature could be used to indirectly probe the presence of DM particles in the location of a cluster.
Constraining the nuclear matter equation of state around twice the saturation density
Energy Technology Data Exchange (ETDEWEB)
Le Fevre, Arnaud; Leifels, Yvonne; Reisdorf, Willibrord [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); Aichelin, Joerg; Hartnack, Christoph [SUBATECH, Universite de Nantes, IN2P3/CNRS (France); Hermann, Norbert [Physikalisches Institut der Universitaet Heidelberg, Heidelberg (Germany)
2014-07-01
From FOPI experimental data on elliptic flow of protons, we extract constraints for the equation of state (EOS) of compressed symmetric nuclear matter using the transport code IQMD. The best agreement with the data is obtained with the soft EOS assumption, including a momentum dependent interaction. The code predicts that the mean characteristical density related to the measured flow is around twice the saturation density. It shows how important is the interplay between the fireball and the spectator matter in the relativistic heavy-ion collisions in order to have the necessary sensitivity of the elliptic flow on the stiffness of the EOS.
A modified explanation of cold nuclear matter effects on J/? production in p+A collisions
Liu, Zhi-Feng
2015-08-01
A modified explanation of the cold nuclear matter (CNM) effects on J/? production in p+A collisions is presented in this paper. The advantage of the modified explanation is that all the CNM effects implemented in this model have clear physical origins and are mostly centered on the idea of multiple parton scattering. With the CNM effects presented in this paper, we calculated the nuclear modification factor RpA in J/? production under different collision energies. The results are compared with the corresponding experiment data and the factors calculated with classic nuclear effects. The factors calculated with CNM effects presented in this paper can accurately reproduce almost all existing J/? measurements in p-A collisions, which is much better than results obtained with the factors calculated with classic nuclear effects. The new model is therefore a more suitable approach to explain CNM effects in the hardproduction of quarkonium. Supported by National Nature Science Foundation of China (10575028)
Nuclear matter and properties from induced reactions and decay
International Nuclear Information System (INIS)
PAINUC experiment obtained the first experimental evidence for the presence of a radiative interaction channel in ?4He interaction: ?±4He??±4He?.The main physical feature of the channel is the good agreement of the ?s energy distributions with the radiation distributions of a Planck blackbody at T?16 MeV. Besides, the first experimental observation of the excitation of the ? resonance, below the threshold energy for pion production, has been obtained. The resonant invariant mass of the ?- system has been measured at M?? =(1157 ± 14) MeV/c2 with a width ?=(38 ± 2) MeV/c2, thus shifted with respect to the free nucleon ? values. The kinematical features of the resonance suggest the involvement of more than one nucleon. The positive pion absorption reaction (?+ 4He? 3pn) in the ? resonance energy region shows strong angular correlations and weak Final and Initial State Interactions (FSI/ISI) among final state nucleons, for all the different two-nucleons and three-nucleons systems. On the basis of model-independent kinematical arguments the branching ratio of pion absorption on systems of three or four nucleons has been evaluated to be ? 14%; even if signatures of pd absorption are observed, where the slow proton is just a spectator, interesting signatures of pure 3-4 nucleon absorption are also present, supporting the hypothesis of the excitation of a nuclear collective resonance. According to the experimental findings, the physical features of the ? induced collective resonance have been extracted, according to a two parameters semi-empirical model, by fitting data from a collection of resonant ?? elastic scattering cross sections. The contributions to the total binding energy per each additional nucleon has been found to be EB >50 MeV, being 7 times more than the binding energy per nucleon in 4He; the interaction strength with the surrounding nuclear medium seems to steeply fall within a range of 1 fm. The direct measurement of the muon neutrino mass is also being studied at PAINUC since the most accessible channel for its direct study is the pion decay. A high precision simulation has been performed, studying the limits on mv imposed by ?? momentum resolutions and masses. The required resolution for resolving a 1 keV/c2 neutrino is 1meV/c: this value can be reached in a near future. The poor pion mass resolution, 350 eV,constrains the accessible mv sector above 419 keV/c2. Finally, from a set of ?± decays, collected at PAINUC, new upper limits of the muon (anti) neutrinos have been extracted
Particle production in hot and dense nuclear matter
International Nuclear Information System (INIS)
The charged particle production in heavy ion reactions at 200 A GeV has been studied for projectiles of 16O and 32S on targets of Al, Cu, Ag and Au. Up to 700 charged particles are measured in the pseudorapidity region -1.7 32S+Au. The measured particle density is used to estimate the energy density attained in central collisions and gives a values of ?2 GeV/fm3. This is close to the energy density predicted for the phase transition from hadronic matter to a quark-gluon plasma. To measure the large number of charged particle produced, finely granulated detector systems are employed. Streamer tube detectors with pad readout and large area, multi-step avalanche chambers with optical readout have been developed for the measurements. The widths of the pseudorapidity distributions of charged particles increase with decreasing centrality of the collision as well as with increasing mass of the target nucleus. This behaviour is assumed to be due to the target fragmentation. The Monte-Carlo model for nucleus-nucleus collisions, VENUS 3.11, which includes rescattering, is in reasonable agreement with the data. The yield of charged particles for central collisions of the heavy targets with 33S is found to be proportional to the target mass, A, at target rapidity. At midrapidity it is approximately proportional to A0.3. At midrapidity the charged particle measurements are supplemented by measurements of the transverse energy. The dimensionless, normalized variances of the multiplicity and transverse energy distributions are, to a large extent, governed by the collision geometry. The change in the normalized variance when studying the charged particle distribution in a narrow angular region is explained as being of statistical nature. (au)
From chiral Lagrangians to Landau Fermi liquid theory of nuclear matter
International Nuclear Information System (INIS)
A simple relation between the effective parameters of chiral Lagrangians in medium as predicted by BR scaling and Landau Fermi liquid parameters is derived. This provides a link between an effective theory of QCD at mean-field level and many-body theory of nuclear matter. It connects in particular the scaling vector-meson mass probed by dileptons produced in heavy-ion collisions (e.g., CERES of CERN-SPS) to the scaling nucleon-mass relevant for low-energy spectroscopic properties, e.g., the nuclear gyromagnetic ratios ?g1 and the effective axial-vector constant g*A. (orig.)
Bressaud, Xavier; Quas, Anthony
2014-01-01
We study a simple two player dynamic game with asymmetric information introduced by Renault and studied by H\\"orner, Rosenberg, Solan and Vieille. We improve the range of parameters for which the optimal startegy is known and provide an unexpected bound on this range.
Status and analysis system of directional dark matter search with nuclear emulsion
International Nuclear Information System (INIS)
We have been doing research and development for direct dark matter search by nuclear emulsion which is a solid state detector. This experiment enable directional detection of dark matter with the large mass target and model independent. Until now, we constructed a base of fully automatic analysis system and nuclear emulsion which can detect sub-micron tracks. We have demonstrated that it is possible to detect recoiled tracks of 100 nm or more by neutron irradiation. This track length is correspond to 37 keV in C(N,O) target. Additionally, we evaluated the angular resolution of the energy basis by using an ion implant system, and obtained 25 degrees or better resolution in 80 keV carbon ions. The fully automatic analysis system which can analyze very short tracks lead the experiment to next phase, we will do a quantitative study of the background toward gram scale test experiment at the Gran Sasso underground laboratory
Low mass dielectrons radiated off cold nuclear matter measured with HADES
Directory of Open Access Journals (Sweden)
Lorenz M.
2014-03-01
Full Text Available The High Acceptance DiElectron Spectrometer HADES [1] is installed at the Helmholtzzentrum für Schwerionenforschung (GSI accelerator facility in Darmstadt. It investigates dielectron emission and strangeness production in the 1-3 AGeV regime. A recent experiment series focusses on medium-modifications of light vector mesons in cold nuclear matter. In two runs, p+p and p+Nb reactions were investigated at 3.5 GeV beam energy; about 9·109 events have been registered. In contrast to other experiments the high acceptance of the HADES allows for a detailed analysis of electron pairs with low momenta relative to nuclear matter, where modifications of the spectral functions of vector mesons are predicted to be most prominent. Comparing these low momentum electron pairs to the reference measurement in the elementary p+p reaction, we find in fact a strong modification of the spectral distribution in the whole vector meson region.
Hot and cold nuclear matter effects in p-Pb collisions at the LHC
Kamin, Jason
2015-05-01
The pA system is typically regarded in heavy ion collisions as a "cold" nuclear matter environment and thought to isolate and identify initial state effects due to the presence of multiple nucleons in the incoming nucleus. Moreover, pA collisions bridge the gap between peripheral AA collisions and the pp baseline to create a more complete understanding of underlying production mechanisms and how they evolve with multiplicity. Recent measurements at both RHIC and the LHC provide an indication, however, that the "cold" nuclear matter picture may be somewhat naïve. Recent LHC results from the 2013 p-Pb run at ?sNN = 5.02 TeV will be discussed.
Inhomogeneous condensates in dilute nuclear matter and BCS-BEC crossovers
International Nuclear Information System (INIS)
We report on recent progress in understanding pairing phenomena in low-density nuclear matter at small and moderate isospin asymmetry. A rich phase diagram has been found comprising various superfluid phases that include a homogeneous and phase-separated BEC phase of deuterons at low density and a homogeneous BCS phase, an inhomogeneous LOFF phase, and a phase-separated BCS phase at higher densities. The transition from the BEC phases to the BCS phases is characterized in terms of the evolution, from strong to weak coupling, of the condensate wavefunction and the second moment of its density distribution in r-space. We briefly discuss approaches to higher-order clustering in low-density nuclear matter.
Inhomogeneous condensates in dilute nuclear matter and BCS-BEC crossovers
Stein, Martin; Huang, Xu-Guang; Clark, John W; Röpke, Gerd
2014-01-01
We report on recent progress in understanding pairing phenomena in low-density nuclear matter at small and moderate isospin asymmetry. A rich phase diagram has been found comprising various superfluid phases that include a homogeneous and phase-separated BEC phase of deuterons at low density and a homogeneous BCS phase, an inhomogeneous LOFF phase, and a phase-separated BCS phase at higher densities. The transition from the BEC phases to the BCS phases is characterized in terms of the evolution, from strong to weak coupling, of the condensate wavefunction and the second moment of its density distribution in $r$-space. We briefly discuss approaches to higher-order clustering in low-density nuclear matter.
Scaled variance, skewness, and kurtosis near the critical point of nuclear matter
Vovchenko, V; Gorenstein, M I; Poberezhnyuk, R V
2015-01-01
The van der Waals (VDW) equation of state predicts the existence of a first-order liquid-gas phase transition and contains a critical point. The VDW equation with Fermi statistics is applied to a description of the nuclear matter. The nucleon number fluctuations near the critical point of nuclear matter are studied. The scaled variance, skewness, and kurtosis diverge at the critical point. It is found that the crossover region of the phase diagram is characterized by the large values of the scaled variance, almost zero skewness, and by the significantly negative kurtosis. The rich structures of the skewness and kurtosis are observed in the phase diagram in the wide region around the critical point, namely, they both may attain large positive or negative values.
Do Skyrme forces that fit nuclear matter work well in finite nuclei?
International Nuclear Information System (INIS)
Full text: A recent exhaustive survey [1] of published Skyrme force paramaterisations, concluded that of more that 200 available Skyrme forces, only 5 satisfied all nuclear matter constraints derived from a combination of experimental results. This subset of Skyrme forces has been comparatively little used in surveys of properties of finite nuclei. We present an analysis of their ability to reproduce such properties, including masses, skin thicknesses, isotope shifts, fission barriers, giant resonances, and fusion properties derived from time-dependent Hartree-Fock calculations. The five forces, despite all being constrained to reproduce nuclear matter observables, show a range of behaviour in their ability to discuss finite nuclei. The consequences for Skyrme force fits are discussed. [1] M. Dutra, O. Lourenco, J. S. Sa Martins, A. Delfino, J. R. Stone and P. D. Stevenson, Phys. Rev. C 85, 035201 (2012). (author)
Energy Technology Data Exchange (ETDEWEB)
Saviankou, Pavel
2009-05-15
In the thesis the effective field theory in NLO and NNLO order is applied. The order NLO still knows no three-particle forces. The theory yields however already in this order the saturation behaviour of nuclear matter. This is due to the fact that in the NLO order the scattering phases are qualitatively correctly reproduced, especially the scattering phases {sup 1}S{sub 0} and {sup 3}S{sub 1} are for energies above 200 MeV negative, which is in all potentials by a so called hard core represented. In the NNLO orde three-particle forces occur, which lead to a larger improvement of the saturation curve, however the saturation point lies still at too high densities. A correction of the low-energy constants by scarcely three percent of the value in the vacuum generates however a saturation curve, which reproduces the empirical binding energy per particle, the density and the compressibility of nuclear matter. About the equation of state of neutron matter is empirically few known. At small densities of neutron matter (k{sub f}<1 fm{sup -1}) the NLO and NNLO orders scarcely differ, but indeed from the free Fermi gas. For applications in finite nuclei a simplified parametrization of the nucleon-nucleon interactions was developed, which reproduces both the known scattering phases with an NLO-comparable accuracy and the empirical saturation behaviour. [German] In der Arbeit wird die Effektive Feldtheorie in der Ordnung NLO und NNLO angewandt. Die Ordnung NLO kennt noch keine Dreiteilchenkraefte. Die Theorie liefert jedoch bereits in dieser Ordnung das Saettigungsverhalten von Kernmaterie. Dies liegt daran, dass bereits in der Ordnung NLO die Streuphasen qualitativ korrekt reproduziert werden, insbesondere sind die Streuphasen {sup 1}S{sub 0} und {sup 3}S{sub 1} fuer Energien oberhalb 200 MeV negativ, was in allen Potentialen durch einen sogenannten ''hard core'' dargestellt wird. In der Ordnung NNLO treten Dreiteilchenkraefte auf, die zu einer grossen Verbesserung der Saettigungskurve fuehren, jedoch liegt der Saettigungspunkt immer noch bei zu hohen Dichten. Eine Korrektur der Niederenergiekonstanten um knapp drei Prozent des Wertes im Vakuum erzeugt jedoch eine Saettigungskurve, die die empirische Bindungsenergie pro Teilchen, die Dichte und die Kompressibilitaet von Kernmaterie reproduziert. Ueber die Zustandsgleichung von Neutronenmaterie ist empirisch wenig bekannt. Bei kleinen Dichten von Neutronenmaterie (k{sub f}<1 fm{sup -1}) unterscheiden sich die Ordnungen NLO und NNLO kaum von einander, wohl aber vom freien Fermigas. Fuer Anwendungen in endlichen Kernen wurde eine vereinfachte Parametrisierung der Nukleon-Nukleon Wechselwirkung entwickelt, die sowohl die bekannten Streuphasen mit einer NLO-vergleichbaren Genauigkeit als auch das empirische Saettigungsverhalten reproduziert. (orig.)
Nuclear spin structure in dark matter search: The zero momentum transfer limit
Bednyakov, V. A.; Simkovic, and F.
2004-01-01
We review the calculation of spin-dependent matrix elements relevant to scattering of weakly interacting massive particles on nuclei. A comprehensive list, to our knowledge, of the proton and neutron total spin expectation values ($$ and $$) calculated within different nuclear models is presented. These values allow a conclusion about the event rate expected in direct dark matter search experiments due to spin-dependent neutralino-nucleon interaction, provided neutralino is ...
Complex nucleon-nucleon interaction based on Brueckner Hartree-Fock calculation of nuclear matter
International Nuclear Information System (INIS)
The elastic and inelastic ?+12C scattering at medium energies is studied using complex ?+12C interaction potential obtained in the folding model using a new complex density dependent interaction which is constructed based on the Brueckner Hartree-Fock calculation of nuclear matter. The new interaction was shown to be very successful in microscopic description of the elastic and inelastic ?+12C scattering to the first excited 2+ and 3- states of 12C. (author)
NDM06: 2. symposium on neutrinos and dark matter in nuclear physics
Energy Technology Data Exchange (ETDEWEB)
Akerib, D.; Arnold, R.; Balantekin, A.; Barabash, A.; Barnabe, H.; Baroni, S.; Baussan, E.; Bellini, F.; Bobisut, F.; Bongrand, M.; Brofferio, Ch.; Capolupo, A.; Carrara Enrico; Caurier, E.; Cermak, P.; Chardin, G.; Civitarese, O.; Couchot, F.; Kerret, H. de; Heros, C. de los; Detwiler, J.; Dracos, M.; Drexlin, G.; Efremenko, Y.; Ejiri, H.; Falchini, E.; Fatemi-Ghomi, N.; Finger, M.Ch.; Finger Miroslav, Ch.; Fiorillo, G.; Fiorini, E.; Fracasso, S.; Frekers, D.; Fushimi, K.I.; Gascon, J.; Genest, M.H.; Georgadze, A.; Giuliani, A.; Goeger-Neff, M.; Gomez-Cadenas, J.J.; Greenfield, M.; H de Jesus, J.; Hallin, A.; Hannestad, St.; Hirai, Sh.; Hoessl, J.; Ianni, A.; Ieva, M.B.; Ishihara, N.; Jullian, S.; Kaim, S.; Kajino, T.; Kayser, B.; Kochetov, O.; Kopylov, A.; Kortelainen, M.; Kroeninger, K.; Lachenmaier, T.; Lalanne, D.; Lanfranchi, J.C.; Lazauskas, R.; Lemrani, A.R.; Li, J.; Mansoulie, B.; Marquet, Ch.; Martinez, J.; Mirizzi, A.; Morfin Jorge, G.; Motz, H.; Murphy, A.; Navas, S.; Niedermeier, L.; Nishiura, H.; Nomachi, M.; Nones, C.; Ogawa, H.; Ogawa, I.; Ohsumi, H.; Palladino, V.; Paniccia, M.; Perotto, L.; Petcov, S.; Pfister, S.; Piquemal, F.; Poves, A.; Praet, Ch.; Raffelt, G.; Ramberg, E.; Rashba, T.; Regnault, N.; Ricol, J.St.; Rodejohann, W.; Rodin, V.; Ruz, J.; Sander, Ch.; Sarazin, X.; Scholberg, K.; Sigl, G.; Simkovic, F.; Sousa, A.; Stanev, T.; Strolger, L.; Suekane, F.; Thomas, J.; Titov, N.; Toivanen, J.; Torrente-Lujan, E.; Tytler, D.; Vala, L.; Vignaud, D.; Vitiello, G.; Vogel, P.; Volkov, G.; Volpe, C.; Wong, H.; Yilmazer, A
2006-07-01
This second symposium on neutrinos and dark matter is aimed at discussing research frontiers and perspectives on currently developing subjects. It has been organized around 6 topics: 1) double beta decays, theory and experiments (particularly: GERDA, MOON, SuperNEMO, CUORE, CANDLES, EXO, and DCBA), 2) neutrinos and nuclear physics, 3) single beta decays and nu-responses, 4) neutrino astrophysics, 5) solar neutrino review, and 6) neutrino oscillations. This document is made up of the slides of the presentations.
Energy Technology Data Exchange (ETDEWEB)
Schenley, R.L.; Griest, W.H.
1990-08-01
Environmental Protection Agency (EPA) methodology for regulatory organics fails to account for the organic matter that is suggested by total organic carbon (TOC) analysis in the Oak Ridge National Laboratory (ORNL) inactive nuclear waste-tank liquids and sludges. Identification and measurement of the total organics are needed to select appropriate waste treatment technologies. An initial investigation was made of the nature of the organics in several waste-tank liquids. This report details the analysis of ORNL wastes.
Nuclear Matter Properties in Derivative Coupling Models Beyond Mean - Field Approximation
Delfino, A; Malheiro, M.; Menezes, D. P.
1996-01-01
The structure of infinite nuclear matter is studied with two of the Zimanyi - Moszkowski (ZM) models in the framework of a relativistic approximation which takes into account Hartree terms and beyond and is compared with the results which come out of the relativistic Hartree - Fock approach in the linear Walecka model. The simple treatment applied to these models can be used in substitution to the more complicated Dirac - Brueckner - Hartree - Fock method to perform future c...
Hadron resonance gas and mean-field nuclear matter for baryon number fluctuations
Fukushima, Kenji
2014-01-01
We give an estimate for the skewness and the kurtosis of the baryon number distribution in two representative models; i.e., models of a hadron resonance gas and relativistic mean-field nuclear matter. We emphasize formal similarity between these two descriptions. The hadron resonance gas leads to a deviation from the Skellam distribution if quantum statistical correlation is taken into account at high baryon density, but this effect is not strong enough to explain fluctuatio...
Vacuum Effects and Compressional Properties of Nuclear Matter in Cutoff Field Theory
Kouno, Hiroaki; Sakamoto, Katsuaki; Iwasaki, Yoshitaka; Noda, Nobuo; Mitsumori, Tomohiro; Koide, Kazuharu; Hasegawa, Akira; Nakano, Masahiro
1997-01-01
Including the vacuum effects, the compressional properties of nuclear matter are studied in the cutoff field theory. Under the Hartree approximation, the low-energy effective Lagrangian is derived in the framework of the renormalization group methods. The coefficients are determined in a way where the physical results hardly depend on the value of the cutoff which is conveniently introduced into the theory. It is shown that, to reproduce the empirical data of the nucleus inc...
Nuclear Matter Properties in Derivative Coupling Models Beyond Mean-Field Approximation
Scientific Electronic Library Online (English)
A., Delfino; M., Malheiro; D. P., Menezes.
1997-09-01
Full Text Available The structure of infinite nuclear matter is studied with two of the Zimanyi - Moszkowski (ZM) models in the framework of a relativistic approximation which takes into account Hartree terms and beyond and is compared with the results which come out of the relativistic Hartree - Fock approach in the l [...] inear Walecka model. The simple treatment applied to these models can be used in substitution to the more complicated Dirac - Brueckner - Hartree - Fock method to perform future calculations in finite nuclei
NDM06: 2. symposium on neutrinos and dark matter in nuclear physics
International Nuclear Information System (INIS)
This second symposium on neutrinos and dark matter is aimed at discussing research frontiers and perspectives on currently developing subjects. It has been organized around 6 topics: 1) double beta decays, theory and experiments (particularly: GERDA, MOON, SuperNEMO, CUORE, CANDLES, EXO, and DCBA), 2) neutrinos and nuclear physics, 3) single beta decays and nu-responses, 4) neutrino astrophysics, 5) solar neutrino review, and 6) neutrino oscillations. This document is made up of the slides of the presentations
Effective interactions and mean field theory: from nuclear matter to nuclei
International Nuclear Information System (INIS)
The Skyrme force is a zero-range force that allows the construction of the mean field inside the nucleus in a simple way. Skyrme forces are reasonably predictive but some features of the infinite nuclear matter or the mass of heavy nuclei are not well computed. The aim of this work is to propose an expanded parametrization of the Skyrme force in order to improve its predictive power. The first part is dedicated to the construction of the expansion of the parametrization. We recall how the effective forces are linked to the nucleon-nucleon interaction then we show the limits of the standard Skyrme forces and we propose a relatively natural improvements based on the integration of spin and isospin instabilities. The second part deals with the validation of the model, first by describing infinite nuclear matter then by studying ?-balanced nuclear matter which has enabled us to reproduce some features of neutron stars like mass and radius. The computation of properties of nuclei like binding energy, mass, radii depends strongly on the adjustment procedure. (A.C.)
Chiral condensate in nuclear matter beyond linear density using chiral Ward identity*
Directory of Open Access Journals (Sweden)
Jido Daisuke
2012-12-01
Full Text Available We discuss density corrections of the chiral condensate up to a NLO order using the chiral Ward identity and an in-medium chiral perturbation theory. The in-medium chiral condensate is calculated by a correlation function of the axial current and pseudoscalar density in the nuclear matter as a consequence of the chiral Ward identity. The correlation function is evaluated using the chiral perturbation theory with the hadronic quantities of pion-nucleon dynamics. We assume that the in-vacuum interaction vertices are known, which means that the in-vacuum loop corrections are renormalized to the tree chiral couplings by taking the values of the couplings in chiral Lagrangian as the physical values. We focus on density order in the physical quantities in our perturbative calculation. This study shows that the medium effects to the chiral condensate beyond the linear density come from density corrections to the ?N sigma term. It implies that calculating the density dependence of the chiral condensate in nuclear matter is essentially equivalent to describe nuclear matter in chiral effective theory.
Nuclear forces and their impact on neutron-rich nuclei and neutron-rich matter
Hebeler, K; Menendez, J; Schwenk, A
2015-01-01
We review the impact of nuclear forces on matter at neutron-rich extremes. Recent results have shown that neutron-rich nuclei become increasingly sensitive to three-nucleon forces, which are at the forefront of theoretical developments based on effective field theories of quantum chromodynamics. This includes the formation of shell structure, the spectroscopy of exotic nuclei, and the location of the neutron dripline. Nuclear forces also constrain the properties of neutron-rich matter, including the neutron skin, the symmetry energy, and the structure of neutron stars. We first review our understanding of three-nucleon forces and show how chiral effective field theory makes unique predictions for many-body forces. Then, we survey results with three-nucleon forces in neutron-rich oxygen and calcium isotopes and neutron-rich matter, which have been explored with a range of many-body methods. Three-nucleon forces therefore provide an exciting link between theoretical, experimental and observational nuclear physi...
International Nuclear Information System (INIS)
The possibilities for studying the physics of nuclear matter at high density and temperature are discussed. Topics presented include: the present situation and the future of heavy ion research; research objectives; accelerator design; and experimental facilities
A comparative study of statistical models for nuclear equation of state of stellar matter
International Nuclear Information System (INIS)
We compare three different statistical models for the equation of state (EOS) of stellar matter at subnuclear densities and temperatures (0.5–10 MeV) expected to occur during the collapse of massive stars and supernova explosions. The models introduce the distributions of various nuclear species in nuclear statistical equilibrium, but use somewhat different nuclear physics inputs. It is demonstrated that the basic thermodynamical quantities of stellar matter under these conditions are similar, except in the region of high densities and low temperatures. We demonstrate that mass and isotopic distributions have considerable differences related to the different assumptions of the models on properties of nuclei at these stellar conditions. Overall, the three models give similar trends, but the details reflect the uncertainties related to the modeling of medium effects, such as the temperature and density dependence of surface and bulk energies of heavy nuclei, and the nuclear shell structure effects. We discuss importance of new physics inputs for astrophysical calculations from experimental data obtained in intermediate energy heavy-ion collisions, in particular, the similarities of the conditions reached during supernova explosions and multifragmentation reactions
Mrs. McNees
2010-11-16
What is matter? All matter we see and can not see is made of atoms. Matter is affected by heat. What is an atom? Molecules? Zoom! All about atoms. Zoom! Atoms arranged in solids. Atomic Arrangements in Solids Atoms and electrons. Atoms and electrons Smaller than electrons are Quarks. Quarks: Inside the Atom What holds a molecule together? What Holds a Molecule Together? The Periodic table Periodic Table What is matter? What is Matter? Methods of heat transfer. Methods of Heat Transfer ...
Equation of state for cold nuclear matter from refractive 16O+16O elastic scattering
International Nuclear Information System (INIS)
The nuclear density overlap, which occurs during refractive heavy-ion scattering, opens an alternative approach to study the equation of state (EOS) for cold nuclear matter. For this purpose elastic 16O+16O scattering at incident enegies of 145, 250, 350, and 480 MeV has been measured very accurately, up to large angles. A systematic folding analysis of these data has been performed using an effective density dependent interaction based on the G-matrix elements of the Paris nucleon-nucleon potential. We find, with the observed refractive scattering patterns, that a soft EOS (with the nuclear incompressibility K around 200 MeV) is the most realistic one
Charge asymmetry in nuclear dynamics
International Nuclear Information System (INIS)
We suggest several ways to study properties of the symmetry term in the nuclear equation of state, EOS, from collective modes in beta-unstable nuclei to dissipative collisions with exotic beams.. After a general discussion on compressibility and saturation density in asymmetric nuclear matter we show some predictions on the collective response based on the solution of generalized Landau dispersion relations. Isoscalar-isovector coupling, disappearance of collectivity and possibility of new instabilities in low and high density regions are discussed with accent on their relation to the symmetry term of effective forces. The energy dependence of charge equilibration dynamics is analysed in connection to the dynamical dipole ?-emission. Finally, isospin effects on reaction mechanisms, from fusion to deep inelastic and fragmentation, and on collective flows appear quite noticeable, opening some appealing experimental perspectives. In particular the onset of chemical plus mechanical instabilities in a dilute asymmetric nuclear matter is discussed with reference to new features in fragmentation reactions. (authors)
International Nuclear Information System (INIS)
The waveform of gravitational waves from the final stage of coalescing low-mass black hole-neutron star binaries depends sensitively on the equation of state of neutron star matter. We show that the observation of such gravitational waves can lead to constraining the nuclear-matter equations of state. (author)
On the manifestation of chiral symmetry in nuclei and dense nuclear matter
Brown, G. E.; Rho, Mannque
2002-06-01
This article reviews our view on how chiral symmetry, its pattern of breaking and restoration under extreme conditions manifest themselves in the nucleon, nuclei, nuclear matter and dense hadronic matter. We discuss how first-principle (QCD) calculations of the properties of finite nuclei can be effectuated by embedding the “standard nuclear physics approach (SNPA)” into the framework of effective field theories of nuclei that incorporate chiral dynamics and then exploit the predictive power of the theory to accurately compute such solar neutrino processes as the proton-proton fusion and the “hep” process and such cosmological nucleosynthesis process as thermal neutron-proton capture etc. The Brown-Rho (BR) scaling that implements chiral symmetry property of baryon-rich medium is re-interpreted in terms of “vector manifestation” of hidden local symmetry à la Harada-Yamawaki. We present a clear direct evidence and a variety of indirect evidences for BR scaling in nuclear processes at normal nuclear matter density probed by weak and electromagnetic fields and at higher density probed by heavy-ion collisions and compact-star observables. We develop the notion of “broadband equilibration” in heavy-ion processes and sharpen the role of strangeness in the formation of compact stars and their collapse into black-holes. We revisit the Cheshire Cat phenomenon first discovered in the skyrmion structure of baryons and more recently revived in the form of “quark-hadron continuity” in mapping low-density structure of hadrons to high-density structure of quarks and gluons and argue once more for the usefulness and power of effective field theories based on chiral symmetry under extreme conditions. It is shown how color-flavor locking in terms of QCD variables and hidden local symmetry in terms of hadronic variables can be connected and how BR scaling fits into this “continuity” scheme exhibiting a novel aspect of the Cheshire Cat phenomenon.
2013-05-17
...License Nos. DPR-39 and DPR-48] In the Matter of Zion Solutions, LLC; Zion Nuclear Power Station, Units 1 and 2; Order Approving...ZionSolutions, LLC (ZS) is the licensee and owner of the Zion Nuclear Power Station, Units 1 and 2 (ZNPS)...
General aspects of the nucleon-nucleon interaction and nuclear matter properties
Energy Technology Data Exchange (ETDEWEB)
Plohl, Oliver
2008-07-25
The subject of the present thesis is at first the investigation of model independent properties of the nucleon-nucleon (NN) interaction in the vacuum concerning the relativistic structure and the implications for nuclear matter properties. Relativistic and non-relativistic meson-exchange potentials, phenomenological potentials s well as potentials based on effective field theory (EFT) are therefore mapped on a relativistic operator basis given by the Clifford Algebra. This allows to compare the various approaches at the level of covariant amplitudes where a remarkable agreement is found. Furthermore, the relativistic self-energy is determined in the Hartree-Fock (HF) approximation. The appearance of a scalar and vector field of several hundred MeV magnitude is a general feature of relativistic descriptions of nuclear matter. Within QCD sum rules these fields arise due to the density dependence of chiral condensates. We find that independent of the applied NN interaction large scalar and vector fields are generated when the symmetries of the Lorentz group are restored. In the framework of chiral EFT (chEFT) it is shown, that these fields are generated by short-range next-to-leading order (NLO) contact terms, which are connected to the spin-orbit interaction. To estimate the effect arising from NN correlations the equation of state of nuclear and neutron matter is calculated in the Brueckner-HF (BHF) approximation applying chEFT. Although, as expected, a clear over-binding is found (at NLO a saturating behavior is observed), the symmetry energy shows realistic properties when compared to phenomenological potentials (within the same approximation) and other approaches. The investigation of the pion mass dependence within chEFT at NLO shows that the magnitude of the scalar and vector fields persists in the chiral limit - nuclear matter is still bound. In contrast to the case of a pion mass larger than the physical one the binding energy and saturation density are decreased in the chiral limit. The present formalism allows within chEFT to perform a consistent comparison of the in-medium nucleon mass and the density dependence of the scalar condensate derived from the Hellmann-Feynman theorem (in HF and BHF approximation). A decoupling of the in-medium nucleon mass and the scalar condensate is observed. It turns out that in contrast to QCD sum rules the effective nucleon mass in matter is mainly determined by short-range contact terms while virtual low-momentum pions provide the essential contributions responsible for the reduction of the in-medium scalar condensate. (orig.)
General aspects of the nucleon-nucleon interaction and nuclear matter properties
International Nuclear Information System (INIS)
The subject of the present thesis is at first the investigation of model independent properties of the nucleon-nucleon (NN) interaction in the vacuum concerning the relativistic structure and the implications for nuclear matter properties. Relativistic and non-relativistic meson-exchange potentials, phenomenological potentials s well as potentials based on effective field theory (EFT) are therefore mapped on a relativistic operator basis given by the Clifford Algebra. This allows to compare the various approaches at the level of covariant amplitudes where a remarkable agreement is found. Furthermore, the relativistic self-energy is determined in the Hartree-Fock (HF) approximation. The appearance of a scalar and vector field of several hundred MeV magnitude is a general feature of relativistic descriptions of nuclear matter. Within QCD sum rules these fields arise due to the density dependence of chiral condensates. We find that independent of the applied NN interaction large scalar and vector fields are generated when the symmetries of the Lorentz group are restored. In the framework of chiral EFT (chEFT) it is shown, that these fields are generated by short-range next-to-leading order (NLO) contact terms, which are connected to the spin-orbit interaction. To estimate the effect arising from NN correlations the equation of state of nuclear and neutron matter is calculated in the Brueckner-HF (BHF) approximation applying chEFT. Although, as expected, a clear over-binding is found (at NLO a saturating behavior is observed), the symmetry energy shows realistic properties when compared to phenomenological potentials (within the same approximation) and other approaches. The investigation of the pion mass dependence within chEFT at NLO shows that the magnitude of the scalar and vector fields persists in the chiral limit - nuclear matter is still bound. In contrast to the case of a pion mass larger than the physical one the binding energy and saturation density are decreased in the chiral limit. The present formalism allows within chEFT to perform a consistent comparison of the in-medium nucleon mass and the density dependence of the scalar condensate derived from the Hellmann-Feynman theorem (in HF and BHF approximation). A decoupling of the in-medium nucleon mass and the scalar condensate is observed. It turns out that in contrast to QCD sum rules the effective nucleon mass in matter is mainly determined by short-range contact terms while virtual low-momentum pions provide the essential contributions responsible for the reduction of the in-medium scalar condensate. (orig.)
Chiral mirror-baryon-meson model and nuclear matter beyond mean-field approximation
Weyrich, Johannes; Strodthoff, Nils; von Smekal, Lorenz
2015-07-01
We consider a chiral baryon-meson model for nucleons and their parity partners in mirror assignment interacting with pions and sigma and omega mesons to describe the liquid-gas transition of nuclear matter together with chiral symmetry restoration in the high density phase. Within the mean-field approximation the model is known to provide a phenomenologically successful description of the nuclear-matter transition. Here, we go beyond this approximation and include mesonic fluctuations by means of the functional renormalization group. While these fluctuations do not lead to major qualitative changes in the phase diagram of the model, beyond the mean-field approximation, one is no longer free to adjust the parameters so as to reproduce the binding energy per nucleon, the nuclear saturation density, and the nucleon sigma term all at the same time. However, the prediction of a clear first-order chiral transition at low temperatures inside the high baryon-density phase appears to be robust.
Energy Technology Data Exchange (ETDEWEB)
Dean, G.
1994-12-31
In this text we give the history of the law creation on the control and safety of nuclear matter. Initially based on the CEA regulation single owner of nuclear matter, the development of nuclear energy has conducted the French government to edict law in relation with IAEA and Euratom recommendations.
Many-body forces, isospin asymmetry and dense hyperonic matter
Gomes, R O; Schramm, S; Vascconcellos, C A Z
2015-01-01
The equation of state (EoS) of asymmetric nuclear matter at high densities is a key topic for the description of matter inside neutron stars. The determination of the properties of asymmetric nuclear matter, such as the symmetry energy ($a_{sym}$) and the slope of the symmetry energy ($L_0$) at saturation density, has been exaustively studied in order to better constrain the nuclear matter EoS. However, differently from symmetric matter properties that are reasonably constrained, the symmetry energy and its slope still large uncertainties in their experimental values. Regarding this subject, some studies point towards small values of the slope of the symmetry energy, while others suggest rather higher values. Such a lack of agreement raised a certain debate in the scientific community. In this paper, we aim to analyse the role of these properties on the behavior of asymmetric hyperonic matter. Using the formalism presented in Ref. (R.O. Gomes et al 2014}, which considers many-body forces contributions in the ...
Dynamical Color Correlations in a $SU(2)_c$ Quark Exchange Model of Nuclear Matter
Gardner, S; Piekarewicz, J
1994-01-01
The quark exchange model is a simple realization of an adiabatic approximation to the strong-coupling limit of Quantum Chromodynamics (QCD): the quarks always coalesce into the lowest energy set of flux tubes. Nuclear matter is thus modeled in terms of its quarks. We wish to study the correlations imposed by total wavefunction antisymmetry when color degrees of freedom are included. To begin with, we have considered one-dimensional matter with a $SU(2)$ color internal degree of freedom only. We proceed by constructing a totally antisymmetric, color singlet {\\it Ansatz} characterized by a variational parameter $\\lambda$ (which describes the length scale over which two quarks in the system are clustered into hadrons) and by performing a variational Monte Carlo calculation of the energy to optimize $\\lambda$ for a fixed density. We calculate the $q-q$ correlation function as well, and discuss the qualitative differences between the system at low and high density.
Response of the XENON100 Dark Matter Detector to Nuclear Recoils
Aprile, E; Arisaka, K; Arneodo, F; Balan, C; Baudis, L; Bauermeister, B; Behrens, A; Beltrame, P; Bokeloh, K; Brown, A; Brown, E; Bruenner, S; Bruno, G; Budnik, R; Cardoso, J M R; Chen, W -T; Choi, B; Colijn, A P; Contreras, H; Cussonneau, J P; Decowski, M P; Duchovni, E; Fattori, S; Ferella, A D; Fulgione, W; Gao, F; Garbini, M; Geis, C; Ghag, C; Giboni, K -L; Goetzke, L W; Grignon, C; Gross, E; Hampel, W; Itay, R; Kaether, F; Kessler, G; Kish, A; Lamblin, J; Landsman, H; Lang, R F; Calloch, M Le; Levy, C; Lim, K E; Lin, Q; Lindemann, S; Lindner, M; Lopes, J A M; Lung, K; Undagoitia, T Marrodan; Massoli, F V; Fernandez, A J Melgarejo; Meng, Y; Messina, M; Molinario, A; Ni, K; Oberlack, U; Orrigo, S E A; Pantic, E; Persiani, R; Plante, G; Priel, N; Rizzo, A; Rosendahl, S; Santos, J M F dos; Sartorelli, G; Schreiner, J; Schumann, M; Lavina, L Scotto; Scovell, P R; Selvi, M; Shagin, P; Simgen, H; Teymourian, A; Thers, D; Vitells, O; Wang, H; Weber, M; Weinheimer, C; Schuhmacher, H; Wiegel, B
2013-01-01
Results from the nuclear recoil calibration of the XENON100 dark matter detector installed underground at the Laboratori Nazionali del Gran Sasso (LNGS), Italy are presented. Data from measurements with an external 241AmBe neutron source are compared with a detailed Monte Carlo simulation which is used to extract the energy dependent charge-yield Qy and relative scintillation efficiency Leff. A very good level of absolute spectral matching is achieved in both observable signal channels - scintillation S1 and ionization S2 - along with agreement in the 2-dimensional particle discrimination space. The results confirm the validity of the derived signal acceptance in earlier reported dark matter searches of the XENON100 experiment.
Does fairness matter in the context of anger about nuclear energy decision making?
Besley, John C
2012-01-01
Several recent studies have questioned whether nonoutcome forms of fairness matter in decision-making situations where individuals feel strongly engaged by the issue at hand. This survey-based study focuses on perceptions about a decision-making process related to a proposal to expand a nuclear power plant in the U.S. Southeast. It finds that anger moderates the impacts of outcome and procedural fairness on willingness to accept a decision process as satisfactory and legitimate. The more anger a person said he or she would feel if a decision were to contradict that person's point of view, the more perceived outcome and procedural fairness mattered. The study also finds that interpersonal fairness is also moderated by anger, but in the opposite direction. Interpersonal fairness had less of an impact on willingness to accept a decision for those who said they would feel angry if the decision did not go their preferred way. PMID:21883331
Hadronization as valon confinement in the course of cooling of nuclear matter
International Nuclear Information System (INIS)
The updated three-phase concept of nuclear matter evolution in course of cooling down - from the phase of quark-gluon plasma through the intermediate phase allowing for massive constituent quarks Q (valons), pions and kaons (Q?K) to the phase of hadronic matter (H) - is exploited for the treatment of relative hadronic yields in the mid-rapidity region of heavy ion collisions. The hadronic yields emerged from thermal treatment of Q?K phase and simple combinatorial approach to the hadronization process are shown to fit the available experimental data from AGS, SPS, and RHIC quite well. Many predictions for the other hadronic yields, which could be observed at these machines as well as at LHC are given
Nuclear matter kinetic coefficients and damping of finite nuclear collective modes
International Nuclear Information System (INIS)
By carrying the general description of one-body observables beyond the mean-field approximation, those correlation terms responsible for Kinetic phenomena and those involved in the renormalization of the G-matrix mean-field in finite nuclei are identified. A Kinetic equation for the one-body density is obtained. Estimates for transport coefficients and for the damping of zero sound are obtained which point to the inadequacy of hydrodynamical descriptions of collective nuclear modes and indicate that collisional damping in large nuclei may account for one or a few tenths of the observed widths. (S.D.)
Neutron star properties and the relativistic nuclear equation of state of many-baryon matter
International Nuclear Information System (INIS)
A relativistic model of baryons interacting via the exchange of ?-, ?-, ?- and ?-mesons (scalar-vector-isovector (SVI) theory) is used to describe the properties of both dense and superdense matter. For the theoretical frame, we used the temperature-dependent Green's function formalism. The equation of state (EOS) is calculated for nuclear as well as neutron matter in the Hartree (H) and Hartree-Fock (HF) approximation. The existence of phase transitions has been investigated. The isotherms of pressure as a function of density show for nuclear matter a critical temperature of about TcHF=16.6 MeV. (As in the usual scalar-vector (SV) theory, the phase transition is absent for neutron matter. A phase transition of both many-baryon systems in the high-pressure and high-density region, which has been found within the SV many-baryon theory, appears in the SVI theory too. The calculated maximum stable masses of neutron stars depend on 1. the underlying parameter set and/or 2. on the chosen approximation (i.e., H, HF; SV-, SVI theory, respectively). Hartree calculations lead to a mass stability limit of MmaxH?2.87 Msun (MmaxH?2.44 Msun when hyperons are taken into account). For the HF calculations we obtained MmaxHF?3.00 Msun (MmaxHF?2.85 Msun). The corresponding maximum radii are (same notation as above) RH?13.2 km (RH?11.8 km), RHF?14.0 km (RHF?13.94 km).) The influence of the approximations, parameter sets and hyperons on the neutron star's moment of inertia is exhibited. (orig.)
Interplay of Three-Body Interactions in the EOS of Nuclear Matter
Zuo, W; Lejeune, A; Lombardo, U.; Mathiot, J.F.
2002-01-01
The equation of state of symmetric nuclear matter has been investigated within Brueckner approach adopting the charge-dependent Argonne $V_{18}$ two-body force plus a microscopic three-body force based on a meson-exchange model. The effects on the equation of state of the individual processes giving rise to the three-body force are explored up to high baryonic density. It is found that the major role is played by the competition between the strongly repulsive $(\\sigma, \\omeg...
International Nuclear Information System (INIS)
We evaluate the in-medium spectral functions for pions, nucleon and isobar resonances in a self consistent and covariant manner. The calculations are based on a recently developed formulation which leads to predictions in terms of the pion-nucleon scattering phase shifts and a set of Migdal parameters describing important short range correlation effects. We do not observe any significant softening of pion modes if we insist on reasonable isobar resonance properties but predict a considerable broadening of the N(1440) and N(1520) resonances in nuclear matter. (orig.)
Enthalpic and entropic phase transitions in high energy density nuclear matter
Iosilevskiy, Igor
2014-01-01
Features of Gas-Liquid (GL) and Quark-Hadron (QH) phase transitions (PT) in dense nuclear matter are under discussion in comparison with their terrestrial counterparts, e.g. so-called "plasma" PT in shock-compressed hydrogen, nitrogen, xenon etc. Both, GLPT and QHPT, when being represented in widely accepted $T - \\mu$ diagram, are often considered as similar, i.e. amenable to one-to-one mapping by simple scaling. It is argued that this impression is illusive and that GLPT an...
Phase Transition in Warm Nuclear Matter with Alternative Derivative Coupling Models
Malheiro, M.; Delfino, A; Coelho, C. T.
1996-01-01
An analysis is performed of the liquid-gas phase transition of nuclear matter obtained from different versions of scalar derivate coupling suggested by Zimanyi and Moszkowski (ZM) and the results are compared with those obtained from the Walecka model. We present the phase diagram for the models and one of them, the ZM3 model, has the lowest critical temperature $T_c=13.6$ MeV with the lowest critical density $\\rho_c=0.037$ f$m^{-3}$ and pressure $p_c=0.157$ MeV f$m^{-3}$. ...