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1

Incompressibility of asymmetric nuclear matter

Energy Technology Data Exchange (ETDEWEB)

The equation of state of asymmetric nuclear matter, calculated with the Seyler-Blanchard (SB) interaction is exploited to find the asymmetry and temperature dependence of the incompressibility of nuclear matter. The incompressibility is found to decrease with both asymmetry and temperature. The results are compared with those obtained from previous calculations and recent experimental findings. The ratio of specific heats is found to increase with asymmetry at all temperatures.

Samanta, C.; Bandyopadhyay, D.; De, J.N.

1989-02-02

2

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 S_0, the density symmetry coefficient L, and the incompressibility K_0 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 S_0 and L, and the upper bound of L which is an increasing function of K_0. 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 K_0. This is a feature that will help to determine the L value via systematic measurements of nuclear size. (author)

2004-04-01

3

Isospin-asymmetric nuclear matter

This study uses classical molecular dynamics to simulate infinite nuclear matter and study the effect of isospin asymmetry on bulk properties such as energy per nucleon, pressure, saturation density, compressibility and symmetry energy. The simulations are performed on systems embedded in periodic boundary conditions with densities and temperatures in the ranges $\\rho$=0.02 to 0.2 fm$^{-3}$ and T = 1, 2, 3, 4 and 5 MeV, and with isospin content of $x=Z/A$=0.3, 0.4 and 0.5. The results indicate that symmetric and asymmetric matter are self-bound at some temperatures and exhibit phase transitions from a liquid phase to a liquid-gas mixture. The main effect of isospin asymmetry is found to be a reduction of the equilibrium densities, a softening of the compressibility and a disappearance of the liquid-gas phase transition. A procedure leading to the evaluation of the symmetry energy and its variation with the temperature was devised, implemented and compared to mean field theory results.

López, J A; González, R; Ravelo, R

2013-01-01

4

Isospin dependent properties of asymmetric nuclear matter

Digital Repository Infrastructure Vision for European Research (DRIVER)

The density dependence of nuclear symmetry energy is determined from a systematic study of the isospin dependent bulk properties of asymmetric nuclear matter using the isoscalar and the isovector components of density dependent M3Y interaction. The incompressibility $K_\\infty$ for the symmetric nuclear matter, the isospin dependent part $K_{asy}$ of the isobaric incompressibility and the slope $L$ are all in excellent agreement with the constraints recently extracted from me...

Chowdhury, P. Roy; Basu, D. N.; Samanta, C.

2009-01-01

5

Response functions of asymmetric nuclear matter

Energy Technology Data Exchange (ETDEWEB)

We consider the spin-isopin response of asymmetric nuclear matter. The associated free and RPA polarization propagators, relative to isospin-flipping operators, are analytically evaluated and the new features with respect to the symmetric matter are pointed out. We suggest the relevance of neutron excess for charge exchange reactions in the region of the quasi-elastic peak. (orig.).

Alberico, W.M.; Drago, A.; Villavecchia, C. (Turin Univ. (Italy). Dipt. di Fisica Teorica Istituto Nazionale di Fisica Nucleare, Turin (Italy))

1989-12-11

6

Response functions of asymmetric nuclear matter

International Nuclear Information System (INIS)

We consider the spin-isopin response of asymmetric nuclear matter. The associated free and RPA polarization propagators, relative to isospin-flipping operators, are analytically evaluated and the new features with respect to the symmetric matter are pointed out. We suggest the relevance of neutron excess for charge exchange reactions in the region of the quasi-elastic peak. (orig.)

1989-12-11

7

Asymmetric nuclear matter equation of state

International Nuclear Information System (INIS)

Systematic calculations of asymmetric nuclear matter have been performed in the framework of the Brueckner-Bethe-Goldstone approach in a wide range of both density and asymmetry parameter. The empirical parabolic law fulfilled by the binding energy per nucleon is confirmed by the present results in all the range of the asymmetry parameter values. The predominant role of the 3S1-3D1 component of the NN interaction is elucidated. A linear variation of the proton and neutron single-particle potentials is found as increasing the neutron excess; a deviation from the phenomenological potentials occurs for highly asymmetric matter as an effect of the self-consistency. The present calculations of the incompressibility predict a strong softening of the equation of state going from symmetric to asymmetric nuclear matter. The proton fraction in equilibrium with neutron matter has been determined from the beta-stability condition and its relevance to the superfluidity of neutron stars has been investigated

1991-01-01

8

Thermal Properties of Asymmetric Nuclear Matter

The thermal properties of asymmetric nuclear matter are investigated in a relativistic mean- field approach. We start from free space NN-interactions and derive in-medium self-energies by Dirac-Brueckner theory. By the DDRH procedure we derive in a self-consistent approach density- dependent meson-baryon vertices. At the mean-field level, we include isoscalar and isovector scalar and vector interactions. The nuclear equation of state is investigated for a large range of total baryon densities up to the neutron star regime, the full range of asymmetries from symmetric nuclear matter to pure neutron matter, and temperatures up to T~100 MeV. The isovector-scalar self-energies are found to modify strongly the thermal properties of asymmetric nuclear matter. A striking result is the change of phase transitions when isovector-scalar self-energies are included.

Fedoseew, Andreas

2014-01-01

9

Symmetry energy coefficients for asymmetric nuclear matter

Digital Repository Infrastructure Vision for European Research (DRIVER)

Symmetry energy coefficients of asymmetric nuclear matter 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 polarizabil...

Braghin, Fa?bio L.

2003-01-01

10

Symmetry energy coefficients for asymmetric nuclear matter

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

2003-01-01

11

Isospin dependent properties of asymmetric nuclear matter

The density dependence of nuclear symmetry energy is determined from a systematic study of the isospin dependent bulk properties of asymmetric nuclear matter using the isoscalar and the isovector components of density dependent M3Y interaction. The incompressibility $K_\\infty$ for the symmetric nuclear matter, the isospin dependent part $K_{asy}$ of the isobaric incompressibility and the slope $L$ are all in excellent agreement with the constraints recently extracted from measured isotopic dependence of the giant monopole resonances in even-A Sn isotopes, from the neutron skin thickness of nuclei and from analyses of experimental data on isospin diffusion and isotopic scaling in intermediate energy heavy-ion collisions. This work provides a fundamental basis for the understanding of nuclear matter under extreme conditions, and validates the important empirical constraints obtained from recent experimental data.

Chowdhury, P Roy; Samanta, C

2009-01-01

12

Symmetry energy coefficients for asymmetric nuclear matter

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english 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.

Fábio L., Braghin.

13

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)

1995-10-01

14

Topological phase transition in asymmetric nuclear matter

Starting from an effective model of asymmetric nuclear matter we show that at finite temperature T and baryon chemical potential ?B there exists a topological phase transition from state of non-Fermi liquid to that of Fermi liquid which is protected by winding numbers. At low ?B the transition is first-order, then extends to a second-order phase transition at larger ?B through a tri-critical point. The isospin dependences of the tri-critical point and the phase diagram in the (T, ?B)-plane are established. The distinction between this type of phase transition and the similar phenomenon caused by the Silver Blaze property (SBP) at T = 0 is confirmed for isospin varying from 0 to 1. We reveal that the topological phase transition could emerge in a large class of nuclear theories.

Phat, Tran Huu; Thu, Nguyen Van

2014-05-01

15

Pseudo-Goldstone modes in isospin-asymmetric nuclear matter

International Nuclear Information System (INIS)

We analyze the chiral limit in dense isoptin-asymmetric nuclear matter. It is shown that the pseudo-Goldstone modes in this system are qualitatively different from the case of isospin-symmetric matter. (author). 20 refs

1994-01-01

16

Higher order bulk characteristic parameters of asymmetric nuclear matter

Digital Repository Infrastructure Vision for European Research (DRIVER)

The bulk parameters characterizing the energy of symmetric nuclear matter and the symmetry energy defined at normal nuclear density $\\rho_0 $ provide important information on the equation of state (EOS) of isospin asymmetric nuclear matter. While significant progress has been made in determining some lower order bulk characteristic parameters, such as the energy $E_0(\\rho_0)$ and incompressibility $K_0$ of symmetric nuclear matter as well as the symmetry energy $E_{sym}(\\rho...

Chen, Lie-wen

2011-01-01

17

EOS and Single Particle Properties of Asymmetric Nuclear Matter

International Nuclear Information System (INIS)

We have investigated the equation of state (EOS) and single particle (s.p.) properties of asymmetric nuclear matter within the framework of the Brueckner-Bethe-Goldstone approach. We have discussed particularly the effect of microscopic three-body forces (TBF). It is shown that the TBF affects significantly the predicted properties of nuclear matter at high densities.

2010-03-01

18

Spin polarized states in strongly asymmetric nuclear matter

International Nuclear Information System (INIS)

The possibility of appearance of spin polarized states in 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 SLy4 and SLy5 effective forces. It is shown that at some critical density strongly asymmetric nuclear matter undergoes 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 clarified that protons become totally polarized within a very narrow density domain while the density profile of the neutron spin polarization parameter is characterized by the appearance of long tails near the transition density

2004-02-01

19

Spin polarized states in strongly asymmetric nuclear matter

The possibility of appearance of spin polarized states in 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 SLy4 and SLy5 effective forces. It is shown that at some critical density strongly asymmetric nuclear matter undergoes 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 clarified that protons become totally polarized within a very narrow density domain while the density profile of the neutron spin polarization parameter is characterized by the appearance of long tails near the transition density.

Isayev, A. A.; Yang, J.

2004-02-01

20

n-p isovector pairing in asymmetric nuclear matter

International Nuclear Information System (INIS)

In this work we present two sets of transformations of the mean pairing field and calculate the pairing field in the n-p isovector channel. Short-range correlations are described in the relativistic nuclear Dirac-Hartree-Fock-Bogoliubov mean field approximation (DHFB), which was originally developed to describe standard pairing in symmetric nuclear matter. The generalization of the approach includes the quasideuteron pairing channel and calculates the pairing modes in asymmetric matter. We construct transformations of the pairing filed using as generators the matrices and and their possible combinations. There are two distinct sets that transform the pairing field in different ways. As a result of these transformations, we found that both pairing fields n-n and p-p can be taken as real functions of k-bar. Calculation of isovector n-p pairing was also based on the decomposition of the fields according to the propagators of Gorkov. As a main result, we found that the inclusion of a new constraint on the model allows solutions for the n-n, p-p and n-p pairing modes in symmetric matter. In asymmetric matter, the only solutions found are the n-n and p-p ones. Thus no isovector n-p pairing solution was found in asymmetric nuclear matter. (author)

2009-01-01

21

Strange particles in asymmetric nuclear matter

International Nuclear Information System (INIS)

The overbinding problem in ?5He is solved by a coherent ?-? coupling which is equivalent to the ?NN three-body force. This three-body force has a significant effect in the ground states of ?4H and ?4He. In ?6H a particle-stable bound state appears with a large ?-? coupling enhanced by excess neutrons. The coherent ?-? coupling becomes much more important in neutron matter at high densities: It causes large ?0 mixing of 5 - 25% at ?=?0 - 3?0. The coherent mixing drastically affects the hyperon composition of neutron-star matter. (author)

2002-09-01

22

Spinodal decomposition of low-density asymmetric nuclear matter

International Nuclear Information System (INIS)

We investigate the dynamical properties of asymmetric nuclear matter at low density. The occurrence of new instabilities, that lead the system to a dynamical fragment formation, is illustrated, discussing in particular the charge symmetry dependence of the structure of the most important unstable modes. We observe that instabilities are reduced by charge asymmetry, leading to larger size and time scales in the fragmentation process. Configurations with less asymmetric fragments surrounded by a more asymmetric gas are favoured. Interesting variances with respect to a pure thermodynamical prediction are revealed, that can be checked experimentally. All these features are deeply related to the structure of the symmetry term in the nuclear equation of state (EOS) and could be used to extract information on the low density part of the EOS. (orig.)

1998-03-16

23

Asymmetric nuclear matter : A variational approach with reid93 interaction

International Nuclear Information System (INIS)

Calculation of asymmetric nuclear matter have been performed in the frame work of the lowest order constrained variational method (LOCV) approach in a wide range of both density and asymmetry parameter. The new charge independent breaking Reid potential (Ried39) used for calculating the equation of state of this system. It is shown that the empirical parabolic law of the binding energy per nucleon is fulfilled in the whole asymmetric range up to high densities. The results compared with the others many body calculations

2006-08-01

24

Pairing effects on spinodal decomposition of asymmetric nuclear matter

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 for gathering information on the temperature dependence of nuclear pairing and, in general, on the properties of clusterised low-density matter, which are of interest also in the astrophysical context.

Burrello, S.; Colonna, M.; Matera, F.

2014-05-01

25

Higher order bulk characteristic parameters of asymmetric nuclear matter

The bulk parameters characterizing the energy of symmetric nuclear matter and the symmetry energy defined at normal nuclear density $\\rho_0 $ provide important information on the equation of state (EOS) of isospin asymmetric nuclear matter. While significant progress has been made in determining some lower order bulk characteristic parameters, such as the energy $E_0(\\rho_0)$ and incompressibility $K_0$ of symmetric nuclear matter as well as the symmetry energy $E_{sym}(\\rho_0)$ and its slope parameter $L$, the higher order bulk characteristic parameters are still poorly known. Here we analyze the correlations between the lower and higher order bulk characteristic parameters within the framework of Skyrme Hartree-Fock energy density functional and then estimate the values of some higher order bulk characteristic parameters. In particular, we obtain $J_0=-355 \\pm 95$ MeV and $I_0=1473 \\pm 680$ MeV for the third-order and fourth-order derivative parameters of symmetric nuclear matter at $\\rho_0 $ and $K_{sym} =...

Chen, Lie-Wen

2011-01-01

26

Asymmetric nuclear matter the role of the isovector scalar channel

We try to single out some qualitative new effects of the coupling to the $\\delta$-isovector-scalar meson introduced in a minimal way in a phenomenological hadronic field theory. Results for the equation of state ($EOS$) and the phase diagram of asymmetric nuclear matter ($ANM$) are discussed. We stress the consistency of the $\\delta$-coupling introduction in a relativistic approach. New contributions to the slope and curvature of the symmetry energy and the neutron-proton effective mass splitting appear particularly interesting. A more repulsive $EOS$ for neutron matter at high baryon densities is expected. Effects on new critical properties of warm $ANM$, mixing of mechanical and chemical instabilities and isospin distillation, are also presented. The $\\delta$ influence is mostly on the {\\it isovectorlike} collective response. The results are largely analytical and this makes the physical meaning quite transparent. Implications for nuclear structure properties of drip-line nuclei and for reaction dynamics wi...

Liu, B; Baran, V; Colonna, M; Di Toro, M

2002-01-01

27

Asymmetric nuclear matter: The role of the isovector scalar channel

International Nuclear Information System (INIS)

We try to single out some qualitative effects of coupling to a ?-isovector-scalar meson, introduced in a minimal way in a phenomenological hadronic field theory. Results for the equation of state (EOS) and the phase diagram of asymmetric nuclear matter (ANM) are discussed. We stress the consistency of the ?-coupling introduction in a relativistic approach. Contributions to the slope and curvature of the symmetry energy and to the neutron-proton effective mass splitting appear particularly interesting. A more repulsive EOS for neutron matter at high baryon densities is expected. Effects on the critical properties of warm ANM, mixing mechanical and chemical instabilities and isospin distillation, are also presented. The ? influence is mostly on the isovectorlike collective response. The results are largely analytical, and this makes the physical meaning quite transparent. Implications for nuclear structure properties of drip-line nuclei and for reaction dynamics with radioactive beams are finally pointed out

2002-04-01

28

Spin polarized states in strongly asymmetric nuclear matter

In the framework of a Fermi liquid theory it is considered the possibility of appearance of spin polarized states in strongly asymmetric nuclear matter with Skyrme effective interaction. The zero temperature dependence of neutron and proton spin polarization parameters as functions of density is found for SLy4, SLy5 effective forces. It is shown that at some critical density it will be formed 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 clarified that protons become totally polarized within very narrow density domain while in the density profile of neutron spin polarization parameter their appear long tails near the transition density.

Isayev, A A

2004-01-01

29

The relativistic treatment of symmetric and asymmetric nuclear matter

International Nuclear Information System (INIS)

In the framework of relativistic nuclear field theory the authors discuss and compare the different approaches in the treatment of nuclear-many-problem with inclusion of two-body correlations. The equations are solved self-consistently in the full Dirac space, so avoiding the ambiguities in the choice of the effective scattering amplitude. The results are compared with the standard method, where one only determines the scattering amplitude for positive energy spinors. Furthermore they tested the assumption of momentum independent self-energy. The results for asymmetric matter are in the structure similar to the outcome of the relativistic Hartree-Fock approximation, but differ from the nonrelativistic treatment. The agreement with the empirical values is quite satisfactory

1993-10-09

30

The relativistic treatment of symmetric and asymmetric nuclear matter

Energy Technology Data Exchange (ETDEWEB)

In the framework of relativistic nuclear field theory the authors discuss and compare the different approaches in the treatment of nuclear-many-problem with inclusion of two-body correlations. The equations are solved self-consistently in the full Dirac space, so avoiding the ambiguities in the choice of the effective scattering amplitude. The results are compared with the standard method, where one only determines the scattering amplitude for positive energy spinors. Furthermore they tested the assumption of momentum independent self-energy. The results for asymmetric matter are in the structure similar to the outcome of the relativistic Hartree-Fock approximation, but differ from the nonrelativistic treatment. The agreement with the empirical values is quite satisfactory.

Huber, H.; Weigel, M.K. [Ludwig-Maximilians-Universitaet Muenchen, Garching (Germany). Sektion Physik; Weber, F. [Lawrence Berkeley Lab., CA (United States)

1993-11-04

31

High-energy behavior of the nuclear symmetry potential in asymmetric nuclear matter

Using the relativistic impulse approximation with empirical NN scattering amplitude and the nuclear scalar and vector densities from the relativistic mean-field theory, we evaluate the Dirac optical potential for neutrons and protons in asymmetric nuclear matter. From the resulting Schr\\"{o}% dinger-equivalent potential, the high energy behavior of the nuclear symmetry potential is studied. We find that the nuclear symmetry potential at fixed nuclear density is essentially constant for nucleon kinetic energy greater than about 500 MeV, and for such high energy nucleons, the nuclear symmetry potential is weakly attractive below a nuclear matter density of about $\\rho =0.22$ fm$^{-3}$ and then increases almost linearly with nuclear density. Our results thus provide an important constraint on the energy and density dependence of nuclear symmetry potential in asymmetric nuclear matter.

Chen, L W; Li, B A

2005-01-01

32

Effects of the equation of state of asymmetric nuclear matter in nuclear collisions

International Nuclear Information System (INIS)

"6"0Ca + "6"0Ca and "1"9"7Au + "1"9"7Au 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)

1999-08-01

33

Critical temperature for ?-particle condensation in asymmetric nuclear matter

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.

2010-09-01

34

Temperature dependence of normal and quasi-deuteron pairing in asymmetric nuclear matter

International Nuclear Information System (INIS)

Nuclear matter calculations show the quasi-deuteron pairing mode to be the most important one and to furnish values of the pairing fields that are in reasonable agreement with the recent measurements. Here, we study the effects of temperature on normal and quasi-deuteron pairing in asymmetric nuclear matter, using a Bonn-type meson exchange interaction.

2009-06-03

35

Effect of Three-body Interaction on Phase Transition of Hot Asymmetric Nuclear Matter

The properties and the isospin dependence of the liquid-gas phase transition in hot asymmetric nuclear matter have been investigated within the framework of the finite temperature Brueckner-Hartree-Fock approach extended to include the contribution of a microscopic three-body force. A typical Van der Waals structure has been observed in the calculated isotherms (of pressure) for symmetric nuclear matter implying the presence of the liquid-gas phase transition. The critical temperature of the phase transition is calculated and its dependence on the proton-to-neutron ratio is discussed. It is shown that the three-body force gives a repulsive contribution to the nuclear equation of state and reduces appreciably the critical temperature and the mechanical instable region. At fixed temperature and density the pressure of asymmetric nuclear matter increases monotonically as a function of isospin asymmetry. In addition, it turns out that the domain of mechanical instability for hot asymmetric nuclear matter graduall...

Zuo, W; Lombardo, U

2004-01-01

36

Spin ordered phase transitions in isospin asymmetric nuclear matter

The possibility of appearance of spin polarized states in nuclear matter is studied within the framework of a Fermi liquid theory with Skyrme effective forces in a wide range of isospin asymmetries and densities. There are a few possible scenarios of spin ordered phase transitions: (a) nuclear matter with SLy4 interaction undergoes at some critical density a phase transition to a spin polarized state with the oppositely directed spins of neutrons and protons; (b) in nuclear matter with SkI5 interaction a spin polarized state with the like-directed neutron and proton spins is formed; (c) nuclear matter with SkI3 interaction under increasing density, at first, undergoes a phase transition to the state with the opposite directions of neutron and proton spins, which goes over at larger density to the state with the same direction of nucleon spins. Spin polarized states at strong excess neutrons over protons are accompanied by the long tails in the density profiles of the neutron spin polarization parameter near t...

Isayev, A A

2006-01-01

37

Cavitation and bubble collapse in hot asymmetric nuclear matter

The dynamics of embryonic bubbles in overheated, viscous and non-Markovian nuclear matter is studied. We show that the memory and the Fermi surface distortions significantly affect the hinderance of bubble collapse and determine a characteristic oscillations of the bubble radius. These oscillations occur due to the additional elastic force induced by the memory integral.

Kolomietz, V M

2004-01-01

38

Properties of dense, asymmetric nuclear matter in Dirac-Brueckner-Hartree-Fock approach

Digital Repository Infrastructure Vision for European Research (DRIVER)

Within the Dirac-Brueckner-Hartree-Fock approach, using the Bonn potentials, we investigate the properties of dense, asymmetric nuclear matter and apply it to neutron stars. In the actual calculations of the nucleon self-energies and the energy density of matter, we study in detail the validity of an angle-averaged approximation and an averaging of the total momentum squared of interacting two-nucleons in nuclear matter. For practical use, we provide convenient parametrizati...

Katayama, Tetsuya; Saito, Koichi

2013-01-01

39

Using the Hugenholtz-Van Hove theorem, we derive general expressions for the quadratic and quartic symmetry energies in terms of single-nucleon potentials in isospin asymmetric nuclear matter. These analytical relations 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.

Xu, Chang; Chen, Lie-Wen; Ko, Che Ming

2010-01-01

40

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.

2011-08-15

41

Spin-ordered phase transitions in isospin asymmetric nuclear matter

International Nuclear Information System (INIS)

Spin polarized states in nuclear matter with Skyrme effective forces are studied on the base of a Fermi liquid theory for a wide range of isospin asymmetries and densities. There are a few possible scenarios of spin ordered phase transitions: (a) nuclear matter with SLy4 interaction undergoes at some critical density a phase transition to a spin polarized state with the oppositely directed spins of neutrons and protons; (b) for SkI5 interaction, a spin polarized state with the like-directed neutron and proton spins is formed; (c) nuclear matter with SkI3 interaction under increasing density, at first, undergoes a phase transition to the state with the opposite directions of neutron and proton spins, which goes over at larger density to the state with the same direction of nucleon spins. Spin polarized states at strong isospin asymmetry are accompanied by the long tails in the density profiles of the neutron spin polarization parameter near the critical density, if the energy gain of the transition from the nonpolarized state to a polarized one is the decreasing function of isospin asymmetry (SLy4 force). If the energy gain is increased with isospin asymmetry, there are no long tails in the density distribution of the neutron spin polarization parameter (SkI3, SkI5 forces)

2006-11-01

42

Spin-ordered phase transitions in isospin asymmetric nuclear matter

Spin polarized states in nuclear matter with Skyrme effective forces are studied on the base of a Fermi liquid theory for a wide range of isospin asymmetries and densities. There are a few possible scenarios of spin ordered phase transitions: (a) nuclear matter with SLy4 interaction undergoes at some critical density a phase transition to a spin polarized state with the oppositely directed spins of neutrons and protons; (b) for SkI5 interaction, a spin polarized state with the like-directed neutron and proton spins is formed; (c) nuclear matter with SkI3 interaction under increasing density, at first, undergoes a phase transition to the state with the opposite directions of neutron and proton spins, which goes over at larger density to the state with the same direction of nucleon spins. Spin polarized states at strong isospin asymmetry are accompanied by the long tails in the density profiles of the neutron spin polarization parameter near the critical density, if the energy gain of the transition from the nonpolarized state to a polarized one is the decreasing function of isospin asymmetry (SLy4 force). If the energy gain is increased with isospin asymmetry, there are no long tails in the density distribution of the neutron spin polarization parameter (SkI3, SkI5 forces).

Isayev, A. A.

2006-11-01

43

Off-Shell Behavior of Nucleon Self-Energy in Asymmetric Nuclear Matter

The off-shell behavior of the nucleon self-energy in isospin asymmetric nuclear matter is investigated within the framework of relativistic Dirac-Brueckner-Hartree-Fock approach based on projection techniques. The dependence of the Dirac components of the self-energy on momentum as well as energy is evaluated for symmetric as well as asymmetric nuclear matter. Special attention is paid to the various contributions to the momentum dependence of the real and imaginary part of the optical potential. The consequences to the different definitions of the effective nucleon mass and particle spectral functions are discussed.

van Dalen, E N E

2010-01-01

44

Correlation functions for a di-neutron condensate in asymmetric nuclear matter

Digital Repository Infrastructure Vision for European Research (DRIVER)

Recent calculations with an effective isospin dependent contact interaction show the possibility of the crossover from superfluidity of neutron Cooper pairs in $^1S_0$ pairing channel to Bose-Einstein condensation (BEC) of di-neutron bound states in dilute nuclear matter. The density and spin correlation functions are calculated for a di-neutron condensate in asymmetric nuclear matter with the aim to find the possible features of the BCS-BEC crossover. It is shown that the z...

Isayev, A. A.

2008-01-01

45

Boiling Patterns of Iso-asymmetric Nuclear Matter

International Nuclear Information System (INIS)

Limits of thermodynamic metastability of self-bound neutron-rich nuclear matter are explored within the framework of microcanonical thermodynamics of interacting Fermi Gas model in Thomas-Fermi approximation. It is found that as the excitation energy per nucleon of the system is increased beyond a certain limiting value, the system loses metastability and becomes unstable with respect to joint fluctuations in excitation energy per nucleon and in isospin per nucleon. As a result, part of the system is forced to boil off in a form of iso-rich non-equilibrated vapors. Left behind in such a process, identifiable with distillation, is a more iso-symmetric metastable residue at a temperature characteristic of its residual isospin content. With a progressing increase in the initial excitation energy per nucleon, more neutron-rich matter is boiled off and a more iso-symmetric residue is left behind with progressively increasing characteristic temperature. Eventually, when all excess neutrons are shed, the system boils uniformly with a further supply of excitation energy, leaving behind a smaller and smaller residue at a characteristic boiling-point temperature of iso-symmetric matter.

2013-03-25

46

Magnetic properties and EoS of spin polarized isospin asymmetric nuclear matter

International Nuclear Information System (INIS)

Bulk and single-particle properties of spin polarized isospin asymmetric nuclear matter are studied within the framework of the Brueckner-Hartree-Fock approximation. The single-particle potentials of neutrons and protons with spin up and down are determined for several values of the neutron and proton spin polarizations and the asymmetry parameter. An analytic parametrization of the total energy per particle as a function of these parameters is constructed, and employed to compute the magnetic susceptibility of nuclear matter. The results show no indication of a ferromagnetic transition at any density for any asymmetry of nuclear matter

2002-11-26

47

Phase Transition Of Asymmetric Nuclear Matter Beyond The 4-Nucleon Model

International Nuclear Information System (INIS)

The contribution of the delta meson to asymmetric nuclear matter (ANM) in the four-nucleon model is considered within the Cornwall-Jackiw-Tomboulis (CJT) effective action approach. In the double-bubble approximation the theory provides the nuclear symmetry energy (NSE) consistent with the recent analysis of experimental data and, at the same time, leads to a softer incompressibility, K0 = 240 MeV, without invoking any additional term similar to the Boguta-Bodmer potential. (author)

2011-12-01

48

Equation of state of asymmetric nuclear matter with Gogny and Coulomb interactions

Energy Technology Data Exchange (ETDEWEB)

The equation of state of the asymmetric nuclear matter is calculated with the Gogny D{sub 1} effective density-dependent nucleon-nucleon interaction and the Coulomb interaction in the framework of the finite-temperature HF method with the rearrangement term. The dependence of the thermodynamical properties such as the critical temperature of the liquid-gas phase transition, the chemical potential, the compression modulus and the entropy of the Coulomb interaction in nuclear matter is treated by using a shielded two-body Coulomb potential and this method has been found to be a reasonable and effective approach.

Huang, S.W.; Fu, M.Z.; Wu, S.S.; Yang, S.D. (Dept. of Physics, Jilin University, Changchun, Jilin 130023 (CN))

1990-06-10

49

International Nuclear Information System (INIS)

Thermal properties of asymmetric nuclear matter are studied within a self-consistent thermal model using an isospin and momentum-dependent interaction (MDI) constrained by the isospin diffusion data in heavy-ion collisions, a momentum-independent interaction (MID), and an isoscalar momentum-dependent interaction (eMDYI). In particular, we study the temperature dependence of the isospin-dependent bulk and single-particle properties, the mechanical and chemical instabilities, and liquid-gas phase transition in hot asymmetric nuclear matter. Our results indicate that the temperature dependence of the equation of state and the symmetry energy are not so sensitive to the momentum dependence of the interaction. The symmetry energy at fixed density is found to generally decrease with temperature and for the MDI interaction the decrement is essentially due to the potential part. It is further shown that only the low momentum part of the single-particle potential and the nucleon effective mass increases significantly with temperature for the momentum-dependent interactions. For the MDI interaction, the low momentum part of the symmetry potential is significantly reduced with increasing temperature. For the mechanical and chemical instabilities as well as the liquid-gas phase transition in hot asymmetric nuclear matter, our results indicate that the boundaries of these instabilities and the phase-coexistence region generally shrink with increasing temperature and are sensitive to the density dependence of the symmetry energy and the isospin and momentum dependence of the nuclear interaction, especially at higher temperatures

2008-01-01

50

A Time Dependent Local Isospin Density Approximation Study of Asymmetric Nuclear Matter

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 different values of the nuclear density $\\rho$ and isospin asymmetry $\\xi=(N-Z)/A$. An analytical expression of the compressibility as a function of $\\rho$ and $\\xi$ is derived which show explicitly an instability of the neutron matter around $\\rho\\simeq 0.09 fm^{-3}$ when a small fraction of protons is added to the system.

Lipparini, Enrico

2013-01-01

51

Neutron optical potentials in unstable nuclei and the equation of state of asymmetric nuclear matter

International Nuclear Information System (INIS)

Neutron single particle potential is one of the basic macroscopic properties to describe structure and reactions of nuclei in nuclear reactors and in the universe. However, the potential is quite uncertain for unstable nuclei primarily because the equation of state (EOS) of asymmetric nuclear matter is not known well. The present authors studied systematically the empirical EOS of asymmetric nuclear matter using a macroscopic nuclear model; about two hundred EOS's having empirically allowed values of L (symmetry energy density derivative coefficient) and K_0 (incompressibility) were obtained from the fittings to masses and radii of stable nuclei. It was suggested that the L value could be determined from global (Z, A) dependence of nuclear radii. In the present study, the single particle potential is examined assuming kinetic energies of non-interacting Fermi gases. The potential in a nucleus can be calculated easily, once the density distribution is solved using the effective nuclear interaction (EOS). Neutron and proton single particle potentials are calculated systematically for "8"0Ni using the two hundred EOS's. It is found that the neutron-proton potential difference has clear and appreciable L dependence, while the potential for each species does not show such simple dependence on L. (author)

2003-06-01

52

Energy Technology Data Exchange (ETDEWEB)

In this work we present two sets of transformations of the mean pairing field and calculate the pairing field in the n-p isovector channel. Short-range correlations are described in the relativistic nuclear Dirac-Hartree-Fock-Bogoliubov mean field approximation (DHFB), which was originally developed to describe standard pairing in symmetric nuclear matter. The generalization of the approach includes the quasideuteron pairing channel and calculates the pairing modes in asymmetric matter. We construct transformations of the pairing filed using as generators the matrices and and their possible combinations. There are two distinct sets that transform the pairing field in different ways. As a result of these transformations, we found that both pairing fields n-n and p-p can be taken as real functions of k-bar. Calculation of isovector n-p pairing was also based on the decomposition of the fields according to the propagators of Gorkov. As a main result, we found that the inclusion of a new constraint on the model allows solutions for the n-n, p-p and n-p pairing modes in symmetric matter. In asymmetric matter, the only solutions found are the n-n and p-p ones. Thus no isovector n-p pairing solution was found in asymmetric nuclear matter. (author)

Quadros, Alex Sander da Costa

2009-07-01

53

Symmetric and asymmetric nuclear matter at finite temperature in a relativistic mean field approach

International Nuclear Information System (INIS)

Ground state and thermostatistical properties of symmetric and asymmetric nuclear matter are studied in the framework of the relativistic mean field theory, with and without the use of non-linear self interaction terms for the scalar meson ?. The dependency of the nuclear symmetry energy and of the bulk symmetry energy on density are studied. The comparison between the results for the non-linear model and for the standard model shows the significance of the nuclear symmetry energy on understanding the properties of neutron-rich nuclei. The quadratic approximation for the volume energy remains valid at higher temperature. Nuclear matter becomes harder to compress with increasing temperature. The level density parameter turns out to depend weakly on the details of the potential used. It decreases strongly with increasing density, is almost independent on asymmetry, and depends weakly on temperature. The nuclear matter equation of state at a finite temperature is derived, and used to study the nuclear liquid-gas phase transition. The transition is found to occur at an excitation energy of 15 - 19 MeV per nucleon, and a density ranging from 0.3 to 0.4 of saturation density for symmetric nuclear matter, in accordance with experimental observations. The critical temperature decreases with increasing asymmetry, and there exists a maximum value for the asymmetry parameter, behind which the nuclear matter becomes stable against the transition. The nuclear liquid-gas phase transition is found to be of first order, i.e., latent heat is needed to convert the liquid into vapor. (author)

1999-01-01

54

The liquid-gas phase transition in hot asymmetric nuclear matter is studied within density-dependent relativistic mean-field models where the density dependence is introduced according to the Brown-Rho scaling and constrained by available data at low densities and empirical properties of nuclear matter. The critical temperature of the liquid-gas phase transition is obtained to be 15.7 MeV in symmetric nuclear matter falling on the lower edge of the small experimental error bars. In hot asymmetric matter, the boundary of the phase-coexistence region is found to be sensitive to the density dependence of the symmetry energy. The critical pressure and the area of phase-coexistence region increases clearly with the softening of the symmetry energy. The critical temperature of hot asymmetric matter separating the gas phase from the LG coexistence phase is found to be higher for the softer symmetry energy.

Zhang, Guang-Hua

2012-01-01

55

Collective modes of asymmetric nuclear matter in Quantum HadroDynamics

We discuss a fully relativistic Landau Fermi liquid theory based on the Quantum Hadro-Dynamics ($QHD$) effective field picture of Nuclear Matter ({\\it NM}). 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. A beautiful ``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 strongly supports 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 $\\delta$-meson-like effective field) on the collective response of asymmetric nuclear matter ($ANM$). Interesting contributions are found on the propagation of isovector-like modes at normal density and on an expe...

Greco, V; Di Toro, M; Matera, F

2003-01-01

56

Systematic calculation of s-wave pion and kaon self-energies in asymmetric nuclear matter

Digital Repository Infrastructure Vision for European Research (DRIVER)

We calculate the pion self-energies in asymmetric nuclear matter in the two-loop approximation of chiral perturbation theory. We find three types of corrections beyond the well-known linear density approximation. The resulting s-wave potential (or equivalent mass-shift) of a $\\pi^-$ in the center of a heavy nucleus like Pb turns out to be $U_{\\pi^-}=\\Delta m_{\\pi^-} \\simeq 14$ MeV, about half of what is needed to form the deeply bound and narrow pionic atom-states recently o...

Kaiser, N.; Weise, W.

2001-01-01

57

We present microscopic calculations of light and medium mass nuclei and the equation of state of symmetric and asymmetric nuclear matter using different nucleon-nucleon forces, including a new Argonne version that has the same spin/isospin structure as local chiral forces at next-to-next-to-leading order (N2LO). The calculations are performed using Auxiliary Field Diffusion Monte Carlo (AFDMC) combined with an improved variational wave function. We show that the AFDMC method can now be used to successfully calculate the energies of very light to medium mass nuclei as well as the energy of isospin-asymmetric nuclear matter, demonstrating microscopically the quadratic dependence of the energy on the symmetry energy.

Gandolfi, S; Carlson, J; Schmidt, Kevin E

2014-01-01

58

Examining the energy dependence of symmetry potential in asymmetric nuclear matter

International Nuclear Information System (INIS)

By using the Hugenholtz–Van Hove (HVH) theorem, the symmetry potential in asymmetric nuclear matter is found to be closely related to symmetry energy Esym(?) and its density slope L(?). The energy dependence of symmetry potential at saturation density ?0 is extracted by using recent constraints on both Esym(?0) and L(?0) from different methods not only in nuclear structures and reactions but also in astrophysics. The extracted symmetry potentials from different methods are found to be generally consistent with each other. By averaging all extracted symmetry potentials, an energy-dependent form of symmetry potential at the saturation density is obtained, which could be useful to calibrate the single-particle potentials in mean-field models of structures and transport models of reactions

2013-09-02

59

The density dependence of the symmetry energy in the equation of state of isospin asymmetric nuclear matter is studied using the isoscaling of the fragment yields and the antisymmetrized molecular dynamic calculation. It is observed that the experimental data at low densities are consistent with the form of symmetry energy,E$_{sym}$ $\\approx$ 31.6 ($\\rho/\\rho_{\\circ})^{0.69}$, in close agreement with those predicted by the results of variational many-body calculation. A comparison of the present result with those reported recently using the NSCL-MSU data suggests that the heavy ion studies favor a dependence of the form, E$_{sym}$ $\\approx$ 31.6 ($\\rho/\\rho_{\\circ})^{\\gamma}$, where $\\gamma$ = 0.6 - 1.05. This constraints the form of the density dependence of the symmetry energy at higher densities, ruling out an extremely " stiff " and " soft " dependences.

Shetty, D V; Souliotis, G A

2005-01-01

60

Momentum, Density, and Isospin dependence of the Symmetric and Asymmetric Nuclear Matter Properties

Properties of symmetric and asymmetric nuclear matter have been investigated in the relativistic Dirac-Brueckner-Hartree-Fock approach based on projection techniques using the Bonn A potential. The momentum, density, and isospin dependence of the optical potentials and nucleon effective masses are studied. It turns out that the isovector optical potential depends sensitively on density and momentum, but is almost insensitive to the isospin asymmetry. Furthermore, the Dirac mass $m^*_D$ and the nonrelativistic mass $m^*_{NR}$ which parametrizes the energy dependence of the single particle spectrum, are both determined from relativistic Dirac-Brueckner-Hartree-Fock calculations. The nonrelativistic mass shows a characteristic peak structure at momenta slightly above the Fermi momentum $\\kf$. The relativistic Dirac mass shows a proton-neutron mass splitting of $m^*_{D,n} m^*_{NR,p}$ which is in agreement with the results from nonrelativistic calculations.

Van Dalen, E N E; Fuchs, C; Faessler, Amand

2005-01-01

61

Spinodal instabilities of asymmetric nuclear matter within the Brueckner--Hartree--Fock approach

We study the spinodal instabilities of asymmetric nuclear matter at finite temperature within the microscopic Brueckner--Hartree--Fock (BHF) approximation using the realistic Argonne V18 nucleon-nucleon potential plus a three-body force of Urbana type. Our results are compared with those obtained with the Skyrme force SLy230a and the relativistic mean field models NL3 and TW. We find that BHF predicts a larger spinodal region. This result is a direct consequence of the fact that our Brueckner calculation predicts a larger critical temperature and saturation density of symmetric nuclear matter than the Skyrme and relativistic mean field ones. We find that the instability is always dominated by total density fluctuations, in agreement with previous results of other authors. We study also the restoration of the isospin symmetry in the liquid phase, {\\it i.e.,} the so-called isospin distillation or fragmentation effect, finding that its efficiency increases with increasing proton fraction and decreases as tempera...

Vidana, Isaac

2008-01-01

62

Asymmetric Higgsino Dark Matter

In the supersymmetric framework, a higgsino asymmetry exists in the universe before the electroweak phase transition. We investigate whether the higgsino is a viable asymmetric dark matter candidate. We find that this is indeed possible. The gauginos, squarks and sleptons must all be very heavy, such that the only electroweak-scale superpartners are the higgsinos. The temperature of the electroweak phase transition must be in the (1-10) GeV range.

Blum, Kfir; Grossman, Yuval; Nir, Yosef; Riotto, Antonio

2012-01-01

63

Isobaric incompressibility of the isospin asymmetric nuclear matter with higher-order contributions

International Nuclear Information System (INIS)

The nuclear matter EoS is calculated using the isoscalar and isovector components of M3Y interaction with density dependence. Density dependence of this DDM3Y effective interaction is completely determined from nuclear matter calculations. Equilibrium density of nuclear matter is determined by minimizing the energy per nucleon

2009-12-08

64

Variational study for the equation of state of asymmetric nuclear matter at finite temperatures

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.

Togashi, H.; Takano, M.

2013-03-01

65

Symmetry Energy in the Equation of State of Asymmetric Nuclear Matter

The symmetry energy is an important quantity in the equation of state of isospin asymmetric nuclear matter. This currently unknown quantity is key to understanding the structure of systems as diverse as the neutron-rich nuclei and neutron stars. At TAMU, we have carried out studies, aimed at understanding the symmetry energy, in a variety of reactions such as, the multifragmentation of $^{40}$Ar, $^{40}$Ca + $^{58}$Fe, $^{58}$Ni and $^{58}$Ni, $^{58}$Fe + $^{58}$Ni, $^{58}$Fe reactions at 25 - 53 AMeV, and deep-inelastic reactions of $^{86}$Kr + $^{124,112}$Sn, $^{64,58}$Ni (25 AMeV), $^{64}$Ni + $^{64,58}$Ni, $^{112,124}$Sn, $^{232}$Th, $^{208}$Pb (25 AMeV) and $^{136}$Xe + $^{64,58}$Ni, $^{112,124}$Sn, $^{232}$Th, $^{197}$Au (20 AMeV). Here we present an overview of some of the results obtained from these studies. The results are analyzed within the framework of statistical and dynamical models, and have important implications for future experiments using beams of neutron-rich nuclei.

Yennello, S J; Souliotis, G A

2007-01-01

66

Asymmetric dense matter in holographic QCD

Directory of Open Access Journals (Sweden)

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.

Shin Ik Jae

2012-02-01

67

International Nuclear Information System (INIS)

We present an upgraded review of our microscopic investigation on the single-particle properties and the EOS of isospin asymmetric nuclear matter within the framework of the Brueckner theory extended to include a microscopic three-body force. We pay special attention to the discussion of the three-body force effect and the comparison of our results with the predictions by other ab initio approaches. Three-body force is shown to be necessary for reproducing the empirical saturation properties of symmetric nuclear matter within nonrelativistic microscopic frameworks, and also for extending the hole-line expansion to a wide density range. The three-body force effect on nuclear symmetry energy is repulsive, and it leads to a significant stiffening of the density dependence of symmetry energy at supra-saturation densities. Within the Brueckner approach, the three-body force affects the nucleon s.p. potentials primarily via its rearrangement contribution which is strongly repulsive and momentum-dependent at high densities and high momenta. Both the rearrangement contribution induced by the three-body force and the effect of ground-state correlations are crucial for predicting reliably the single-particle properties within the Brueckner framework. (orig.)

2014-02-01

68

Energy Technology Data Exchange (ETDEWEB)

We present an upgraded review of our microscopic investigation on the single-particle properties and the EOS of isospin asymmetric nuclear matter within the framework of the Brueckner theory extended to include a microscopic three-body force. We pay special attention to the discussion of the three-body force effect and the comparison of our results with the predictions by other ab initio approaches. Three-body force is shown to be necessary for reproducing the empirical saturation properties of symmetric nuclear matter within nonrelativistic microscopic frameworks, and also for extending the hole-line expansion to a wide density range. The three-body force effect on nuclear symmetry energy is repulsive, and it leads to a significant stiffening of the density dependence of symmetry energy at supra-saturation densities. Within the Brueckner approach, the three-body force affects the nucleon s.p. potentials primarily via its rearrangement contribution which is strongly repulsive and momentum-dependent at high densities and high momenta. Both the rearrangement contribution induced by the three-body force and the effect of ground-state correlations are crucial for predicting reliably the single-particle properties within the Brueckner framework. (orig.)

Zuo, Wei [Chinese Academy of Sciences, Institute of Modern Physics, Lanzhou (China); Chinese Academy of Sciences, State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Beijing (China); Bombaci, Ignazio [Universita di Pisa (Italy); INFN, Sezione di Pisa, Dipartimento di Fisica ' ' E. Fermi' ' (Italy); Lombardo, Umberto [Universita di Catania (Italy); Laboratori Nazionali del Sud (INFN), Catania (Italy)

2014-02-15

69

A two-component isospin lattice gas model has been employed to study the liquid-gas phase transition for asymmetric nuclear matter. An additional degree of freedom, namely, the asymmetry parameter alpha, has been considered carefully for studying the phase transition. We have shown that under the mean field approximation, the liquid-gas phase transition given by this model is of second order. The entropy continues at the phase transition point. The binodal surface is addressed.

Qian Wei Liang

2003-01-01

70

A two-components isospin lattice gas model has been employed to study the liquid-gas phase transition for asymmetric nuclear matter. An additional degree of freedom, namely, the asymmetry parameter alpha has been considered carefully for studying the phase transition. We have shown that under the mean field approximation, the liquid-gas phase transition given by this model is of second order. The entropy continues at the phase transition point. The binodal surface is addressed.

Qian, W L; Qian, Wei Liang; Su, Ru-Keng

2003-01-01

71

Low density instabilities in asymmetric nuclear matter within QMC with $\\delta$-meson

In the present work we include the isovector-scalar $\\delta$-meson in the quark-meson coupling model (QMC) and study the properties of asymmetric nuclear within QMC without and with the $\\delta$-meson. Recent constraints set by isospin diffusion on the slope parameter of the nuclear symmetry energy at saturation density are used to adjust the model parameters. The thermodynamical spinodal surfaces are obtained and the instability region at subsaturation densities within QMC and QMC$\\delta$ models are compared with mean-field relativistic models. The distillation effect in the QMC model is discussed.

Santos, Alexandre M; Providência, Constança

2009-01-01

72

Predicting the single-proton/neutron potentials in asymmetric nuclear matter

We discuss the one-body potentials for protons and neutrons obtained from Dirac-Brueckner-Hartree-Fock calculations of neutron-rich matter, in particular their dependence upon the degree of proton/neutron asymmetry. The closely related symmetry potential is compared with empirical information from the isovector component of the nuclear optical potential.

Sammarruca, F; Krastev, P

2004-01-01

73

Cluster formation in asymmetric nuclear matter: semi-classical and quantal approaches

The nuclear-matter liquid-gas phase transition induces instabilities against finite-size density fluctuations. This has implications for both heavy-ion-collision and compact-star physics. In this paper, we study the clusterization properties of nuclear matter in a scenario of spinodal decomposition, comparing three different approaches: the quantal RPA, its semi-classical limit (Vlasov method), and a hydrodynamical framework. The predictions related to clusterization are qualitatively in good agreement varying the approach and the nuclear interaction. Nevertheless, it is shown that i) the quantum effects reduce the instability zone, and disfavor short-wavelength fluctuations; ii) large differences appear bewteen the two semi-classical approaches, which correspond respectively to a collisionless (Vlasov) and local equilibrium description (hydrodynamics); iii) the isospin-distillation effect is stronger in the local equilibrium framework; iv) important variations between the predicted time-scales of cluster for...

Ducoin, C; Chomaz, Ph

2008-01-01

74

Equation of State of Symmetric And Asymmetric Nuclear Matter At Various Densities And Temperatures

International Nuclear Information System (INIS)

The equation of state (EOS) of nuclear matter (NM) is an important ingredient in the study of properties of nuclei at and far from stability, of structures and evolution of compact astrophysical objects, such as neutron stars and core-collapse supernovae, and of heavy-ion collisions (HIC). We will review the current status of the EOS of NM, as deduced from theoretical and experimental studies of structure and reactions of nuclei.

2012-02-08

75

Originally Asymmetric Dark Matter

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...

Okada, Nobuchika

2012-01-01

76

?-? mixing in asymmetric nuclear matter via a QCD sum rule approach

International Nuclear Information System (INIS)

We evaluate the operator product expansion (OPE) for a mixed correlator of the isovector and isoscalar vector currents in the background of the nucleon density with intrinsic isospin asymmetry (i.e., excess of neutrons over protons) and match it with its imaginary part, given by resonances and continuum, via the dispersion relation. The leading density-dependent contribution to ?-? mixing is due to the scattering term, which turns out to be larger than any density dependent piece in the OPE. We estimate that the asymmetric density of nn-np?2.5x10-2fm-3 induces the amplitude of ?-? mixing, equal in magnitude to the mixing amplitude in vacuum, with the constructive interference for positive and destructive for negative values of nn-np. We revisit sum rules for vector meson masses at finite nucleon density to point out the numerical importance of the screening term in the isoscalar channel, which turns out to be one order of magnitude larger than any density-dependent condensates over the Borel window. This changes the conclusions about the density dependence of m?, indicating ?40MeV increase at nuclear saturation density

2001-01-01

77

Active matter on asymmetric substrates

For collections of particles in a thermal bath interacting with an asymmetric substrate, it is possible for a ratchet effect to occur where the particles undergo a net dc motion in response to an ac forcing. Ratchet effects have been demonstrated in a variety of systems including colloids as well as magnetic vortices in type-II superconductors. Here we examine the case of active matter or self-driven particles interacting with asymmetric substrates. Active matter systems include self-motile colloidal particles undergoing catalysis, swimming bacteria, artificial swimmers, crawling cells, and motor proteins. We show that a ratchet effect can arise in this type of system even in the absence of ac forcing. The directed motion occurs for certain particle-substrate interaction rules and its magnitude depends on the amount of time the particles spend swimming in one direction before turning and swimming in a new direction. For strictly Brownian particles there is no ratchet effect. If the particles reflect off the barriers or scatter from the barriers according to Snell's law there is no ratchet effect; however, if the particles can align with the barriers or move along the barriers, directed motion arises. We also find that under certain motion rules, particles accumulate along the walls of the container in agreement with experiment. We also examine pattern formation for synchronized particle motion. We discuss possible applications of this system for self-assembly, extracting work, and sorting as well as future directions such as considering collective interactions and flocking models.

Olson Reichhardt, C. J.; Drocco, J.; Mai, T.; Wan, M. B.; Reichhardt, C.

2011-09-01

78

BCS-BEC crossover of neutron pairs in symmetric and asymmetric nuclear matter

Digital Repository Infrastructure Vision for European Research (DRIVER)

We propose new types of density dependent contact pairing interaction which reproduce the pairing gaps in symmetric and neutron matter obtained by a microscopic treatment based on the nucleon-nucleon interaction. These interactions are able to simulate the pairing gaps of either the bare interaction or the interaction screened by the medium polarization effects. It is shown that the medium polarization effects cannot be cast into the density power law function usually introd...

Margueron, J.; Sagawa, Hiroyuki; Hagino, Kouichi

2007-01-01

79

Stable Bound States of Asymmetric Dark Matter

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. For a range of parameters the Yukawa coupling of the dark matter to the mediator gives rise to stable asymmetric dark matter bound states. We derive properties of the bound states including nuggets formed from $N\\gg1$ dark matter particles. We also consider the formation of bound states in the early universe and direct detection of dark matter bound states. Many of our results also hold for symmetric dark matter.

Wise, Mark B

2014-01-01

80

Energy Technology Data Exchange (ETDEWEB)

After reviewing our microscopic approach to nuclear and neutron-rich matter, we focus on how nucleon-nucleon scattering is impacted by the presence of a dense hadronic medium, with special emphasis on the case where neutron and proton densities are different. We discuss in detail medium and isospin asymmetry effects on the total elastic cross section and the mean free path of a neutron or a proton in isospin-asymmetric nuclear matter. We point out that in-medium cross sections play an important role in heavy-ion simulations aimed at extracting constraints on the symmetry potential. We argue that medium and isospin dependence of microscopic cross sections are the result of a complex balance among various effects, and cannot be simulated with a simple phenomenological model. (orig.)

Sammarruca, F. [University of Idaho, Physics Department, Moscow, ID (United States)

2014-02-15

81

Self-consistent mean field methods based on phenomenological Skyrme effective interactions are known to exhibit spurious spin and spin-isospin instabilities both at zero and finite temperatures when applied to homogeneous nuclear matter at the densities encountered in neutron stars and in supernova cores. The origin of these instabilities is revisited in the framework of the nuclear energy density functional theory and a simple prescription is proposed to remove them. The stability of several Skyrme parametrizations is reexamined.

Chamel, N; 10.1103/PhysRevC.82.045804

2010-01-01

82

Nuclear matter and surface clustering

International Nuclear Information System (INIS)

We demonstrate that the binding energy per nucleon of symmetric nuclear matter (SNM) (with Coulomb interaction switched off and N = Z) in the limit of zero density approaches to its value, uv, at the saturation density, where uv is the volume term of the Weizsäcker mass formula. This phenomenon is a direct result of the clustering of nuclei in the low density region of nuclear matter. We study the implications of this result on the properties of nuclei. We also study the properties of asymmetric nuclear matter. Because of clustering a provocative interpretation of the equation of state of asymmetric nuclear matter emerges which is at considerable variance at low densities with hitherto all the previous calculations. For nuclei, as a framework, an extended version of Thomas-Fermi theory is invoked. Calculations are performed for 2149 nuclei with N, Z ? 8. The present scheme leads to a forceful interpretation of the low density asymmetry energy data of Natowitz et al. [1].

2013-04-17

83

Phenomenology of Light Fermionic Asymmetric Dark Matter

Digital Repository Infrastructure Vision for European Research (DRIVER)

Asymmetric dark matter (ADM) has been an attractive possibility attempting to explain the observed ratio of baryon to dark matter abundance in the universe. While a bosonic ADM is constrained by the limits from existence of old neutron stars, a fermionic ADM requires an additional light particle in order to annihilate its symmetric component in the early universe. We revisit the phenomenology of a minimal GeV scale fermionic ADM model including a light scalar state. The curr...

Bhattacherjee, Biplob; Matsumoto, Shigeki; Mukhopadhyay, Satyanarayan; Nojiri, Mihoko M.

2013-01-01

84

Baryon Destruction by Asymmetric Dark Matter

We investigate new and unusual signals that arise in theories where dark matter is asymmetric and carries a net antibaryon number, as may occur when the dark matter abundance is linked to the baryon abundance. Antibaryonic dark matter can cause {\\it induced nucleon decay} by annihilating visible baryons through inelastic scattering. These processes lead to an effective nucleon lifetime of 10^{29}-10^{32} years in terrestrial nucleon decay experiments, if baryon number transfer between visible and dark sectors arises through new physics at the weak scale. The possibility of induced nucleon decay motivates a novel approach for direct detection of cosmic dark matter in nucleon decay experiments. Monojet searches (and related signatures) at hadron colliders also provide a complementary probe of weak-scale dark-matter--induced baryon number violation. Finally, we discuss the effects of baryon-destroying dark matter on stellar systems and show that it can be consistent with existing observations.

Davoudiasl, Hooman; Sigurdson, Kris; Tulin, Sean

2011-01-01

85

Baryon destruction by asymmetric dark matter

International Nuclear Information System (INIS)

We investigate new and unusual signals that arise in theories where dark matter is asymmetric and carries a net antibaryon number, as may occur when the dark matter abundance is linked to the baryon abundance. Antibaryonic dark matter can cause induced nucleon decay by annihilating visible baryons through inelastic scattering. These processes lead to an effective nucleon lifetime of 1029-1032 yrs in terrestrial nucleon decay experiments, if baryon number transfer between visible and dark sectors arises through new physics at the weak scale. The possibility of induced nucleon decay motivates a novel approach for direct detection of cosmic dark matter in nucleon decay experiments. Monojet searches (and related signatures) at hadron colliders also provide a complementary probe of weak-scale dark-matter-induced baryon number violation. Finally, we discuss the effects of baryon-destroying dark matter on stellar systems and show that it can be consistent with existing observations.

2011-11-01

86

Phenomenology of Fermionic Asymmetric Dark Matter

Asymmetric dark matter (ADM) has been an attractive possibility attempting to explain the observed ratio of baryon to dark matter abundance in the universe. While a bosonic ADM is highly constrained by the limits from existence of old neutron stars, a fermionic ADM requires an additional light particle in order to annihilate its symmetric component in the early universe. We revisit the phenomenology of a minimal fermionic ADM model including a light scalar state. The current constraints on this scenario from cosmology, dark matter direct detection, flavour physics and collider searches are investigated in detail. We estimate the future reach on the model parameter space from next-generation dark matter direct detection experiments, Higgs boson property measurements and search for light scalars at the LHC, as well as the determination of Higgs invisible branching ratio at the proposed ILC.

Bhattacherjee, Biplob; Mukhopadhyay, Satyanarayan; Nojiri, Mihoko M

2013-01-01

87

Correlations in exotic nuclear matter

Energy Technology Data Exchange (ETDEWEB)

We investigate short range correlations in asymmetric nuclear and hypernuclear matter. Self-energies due to short range correlations and their influence on the nucleon and {lambda}-hyperon spectral functions are described in an approach accounting for a realistic treatment of mean-field dynamics by a phenomenological Skyrme energy density functional. Landau-Migdal theory is used to derived the short range interaction from the Skyrme energy density functional, especially investigating short-range dynamics by subtracting the long range pionic contributions to the nucleonic spectral functions. The sensitivity of correlations on the parameters of underlying Skyrme energy density functional is discussed. Results on self-energies and spectral functions in asymmetric nuclear matter, hypermatter and {beta}-stable ({lambda},n,p,e)-neutron star matter are presented.

Konrad, Patrick; Lenske, Horst [Institut fuer Theoretische Physik, Universitaet Giessen (Germany)

2009-07-01

88

Annihilation Signals from Asymmetric Dark Matter

In the simplest models of asymmetric dark matter (ADM) annihilation signals are not expected, since the DM is non-self-conjugate and the relic density of anti-DM is negligible. We investigate a new class of models in which a symmetric DM component, in the `low-mass' 1-10 GeV regime favoured for linking the DM and baryon asymmetries, is repopulated through decays. We find that, in models without significant velocity dependence of the annihilation cross section, observational constraints generally force these decays to be (cosmologically) slow. These late decays can give rise to gamma-ray signal morphologies differing from usual annihilation profiles. A distinctive feature of such models is that signals may be absent from dwarf spheroidal galaxies.

Hardy, Edward; Unwin, James

2014-01-01

89

Variational approach to nuclear matter

International Nuclear Information System (INIS)

We calculated the energies of asymmetric nuclear matter at zero and finite temperatures with the cluster variational method. At zero temperature, the expectation value of the two-body Hamiltonian composed of the kinetic energies and the AV18 two-body forces is calculated with the Jastrow wave function in the two-body cluster approximation. The obtained two-body energy is in good agreement with the result with the Fermi Hypernetted Chain (FHNC) calculation by Akmal et al. The energy caused by the UIX three-body forces is treated somewhat phenomenologically so that the total energy reproduces the empirical saturation point. Furthermore, the parameters included in the three-body energy are readjusted so that the Thomas-Fermi (TF) calculations with use of the obtained energy of nuclear matter reproduce the gross feature of the experimental data on atomic nuclei. The nuclear species in the neutron star crust obtained by the TF calculation are reasonable. The free energies of asymmetric nuclear matter at finite temperatures are calculated with an extension of the method proposed by Schmidt and Pandharipande. The obtained free energies are in good agreement with those with the FHNC method, and it is also found that the present variational method is self-consistent. It is remarkable that the symmetry free energy is not proportional to (1 - 2x)2, where x is the proton fraction. With use of the obtained thermodynamic quantities, we are constructing a new nuclear equation of state for supernova simulations. (author)

2010-12-01

90

Chiral thermodynamics of nuclear matter

The free energy and the equation of state of isospin-asymmetric nuclear matter are calculated at finite temperature up to three loop order in the framework of in-medium chiral perturbation theory, systematically incorporating one- and two-pion exchange dynamics to this order. Effects from the two-pion exchange with explicit {\\Delta}-isobar excitation are included, as well as three-body forces. We construct the phase diagram of nuclear matter for different proton fractions x_p and investigate the dependence of nuclear matter properties on the isospin-asymmetry. A detailed study of the liquid-gas phase transition is performed. For isospin-symmetric nuclear matter we find a critical temperature of 15.1 MeV; as the isospin-asymmetry is increased, the liquid-gas coexistence region decreases until it disappears at x_p \\approx 0.05, while nuclear matter becomes unbound at x_p \\approx 0.12. The quadratic expansion of the free energy in the asymmetry parameter {\\delta} is a good approximation at low temperature even f...

Fiorilla, Salvatore; Weise, Wolfram

2011-01-01

91

Exotic States of Nuclear Matter

pt. A. Theory of nuclear matter EOS and symmetry energy. Constraining the nuclear equation of state from astrophysics and heavy ion reactions / C. Fuchs. In-medium hadronic interactions and the nuclear equation of state / F. Sammarruca. EOS and single-particle properties of isospin-asymmetric nuclear matter within the Brueckner theory / W. Zuo, U. Lombardo & H.-J. Schulze. Thermodynamics of correlated nuclear matter / A. Polls ... [et al.]. The validity of the LOCV formalism and neutron star properties / H. R. Moshfegh ... [et al.]. Ferromagnetic instabilities of neutron matter: microscopic versus phenomenological approaches / I. Vidaã. Sigma meson and nuclear matter saturation / A. B. Santra & U. Lombardo. Ramifications of the nuclear symmetry energy for neutron stars, nuclei and heavy-ion collisions / A. W. Steiner, B.-A. Li & M. Prakash. The symmetry energy in nuclei and nuclear matter / A. E. L. Dieperink. Probing the symmetry energy at supra-saturation densities / M. Di Toro et al. Investigation of low-density symmetry energy via nucleon and fragment observables / H. H. Wolter et al. Instability against cluster formation in nuclear and compact-star matter / C. Ducoin ... [et al.]. Microscopic optical potentials of nucleon-nucleus and nucleus-nucleus scattering / Z.-Y. Ma, J. Rong & Y.-Q. Ma -- pt. B. The neutron star crust: structure, formation and dynamics. Neutron star crust beyond the Wigner-Seitz approximation / N. Chamel. The inner crust of a neutron star within the Wigner-Seitz method with pairing: from drip point to the bottom / E. E. Saperstein, M. Baldo & S. V. Tolokonnikov. Nuclear superfluidity and thermal properties of neutron stars / N. Sandulescu. Collective excitations: from exotic nuclei to the crust of neutron stars / E. Khan, M. Grasso & J. Margueron. Monte Carlo simulation of the nuclear medium: fermi gases, nuclei and the role of Pauli potentials / M. A. Pérez-García. Low-density instabilities in relativistic hadronic models / C. Providência et al. Quartetting in nuclear matter and [symbol] particle condensation in nuclear systems / G. Röpke & P. Schuck et al. -- pt. C. Neutron star structure and dynamics. Shear viscosity of neutron matter from realistic nuclear interactions / O. Benhar & M. Valli. Protoneutron star dynamo: theory and observations / A. Bonanno & V. Urpin. Magnetic field dissipation in neutron stars: from magnetars to isolated neutron stars / J. A. Pons. Gravitational radiation and equations of state in super-dense cores of core-collapse supernovae / K. Kotake. Joule heating in the cooling of magnetized neutron stars / D. N. Aguilera, J. A. Pons & J. A. Miralles. Exotic fermi surface of dense neutron matter / M. V. Zverev, V. A. Khodel & J. W. Clark. Coupling of nuclear and electron modes in relativistic stellar matter / A. M. S. Santos et al. Neutron stars in the relativistic Hartree-Fock theory and hadron-quark phase transition / B. Y. Sun ... [et al.] -- pt. D. Prospects of present and future observations. Measurements of neutron star masses / D. G. Yakovlev. Dense nuclear matter: constraints from neutron stars / J. M. Lattimer. Neutron star versus heavy-ion data: is the nuclear equation of state hard or soft? / J. Schaffner-Bielich ... [et al.]. Surface emission from x-ray dim isolated neutron stars / R. Turolla. High energy neutrino astronomy / E. Migneco. What gravitational waves say about the inner structure of neutron stars / V. Ferrari. Reconciling 2 M[symbol] pulsars and SN1987A: two branches of neutron stars / P. Haensel, M. Bejger & J. L. Zdunik. EOS of dense matter and fast rotation of neutron stars / J. L. Zdunik ... [et al.] -- pt. E. Quark and strange matter in neutron stars. Bulk viscosity of color-superconducting quark matter / M. Alford. Chiral symmetry restoration and quark deconfinement at large densities and temperature / A. Drago, L. Bonanno & A. Lavagno. Color superconducting quark matter in compact stars / D. B. Blaschke, T. Klähn & F. Sandin. Thermal hadronization, Hawking-Unruh radiation and e

Lombardo, Umberto; Baldo, Marcello; Burgio, Fiorella; Schulze, Hans-Josef

2008-02-01

92

Nuclear Symmetry energy in chiral model of nuclear matter

International Nuclear Information System (INIS)

The physical properties of asymmetric nuclear matter are studied in the Extended Nambou-Jona-Lasinio (ENJL) model formulated directly in the nucleon degrees of freedom. It results that the density dependence of the nuclear symmetry energy and its related quantities are basically in good agreement with data of recent analyses. (author)

2012-06-01

93

Energy Technology Data Exchange (ETDEWEB)

We review the present statiis of the many-body theory of nuclear and pure neutron matter based on realistic models of nuclear forces, The current models of two- and three-nucleon interactions are discussed along with recent results obtained with the Brueckner and variatioual methods. New initiatives in the variational method and quantuni Monte Carlo nicthods to study pure neutron matter are described, and finally, the analytic behavior of the energy of piire neutron matter at low densities is cliscussed.

Carlson, J. A. (Joseph A.); Cowell, S.; Morales, J.; Ravenhall, D. G.; Pandharipande, V. R. (Vijay R.)

2002-01-01

94

International Nuclear Information System (INIS)

It is stated that at the Workshop on Nuclear and Dense Matter held at the University of Illinois in May 1977 significant progress was reported that largely resolves many of the questions raised in this journal Vol. 6, p.149, 1976. These include perturbative versus variational methods as applied to nuclear matter, exact solutions for bosons, what is known as the fermion 'homework problem', and various other considerations regarding nuclear matter, including the use of variational methods as opposed to perturbation theory. (15 references) (U.K.)

1978-01-01

95

Asymmetric neutrino emission in quark matter and pulsar kicks

The puzzling phenomenon of pulsar kicks, i.e. the observed large escape velocities of pulsars out of supernova remnants, is examined for compact stars with a strange quark matter core. The direct Urca process in quark matter is studied in the presence of a strong magnetic field. Conditions for an asymmetric emission of the produced neutrinos are worked out in detail, giving constraints on the temperature, the strength of the magnetic field and the electron chemical potential in the quark matter core. In addition, the neutrino mean free paths for quark matter and a possible hadronic mantle are considered.

Sagert, I

2006-01-01

96

Asymmetric neutrino emission in quark matter and pulsar kicks

Digital Repository Infrastructure Vision for European Research (DRIVER)

The puzzling phenomenon of pulsar kicks, i.e. the observed large escape velocities of pulsars out of supernova remnants, is examined for compact stars with a strange quark matter core. The direct Urca process in quark matter is studied in the presence of a strong magnetic field. Conditions for an asymmetric emission of the produced neutrinos are worked out in detail, giving constraints on the temperature, the strength of the magnetic field and the electron chemical potential...

Sagert, I.; Schaffner-bielich, J.

2006-01-01

97

Asymmetric dark matter and the Sun

DEFF Research Database (Denmark)

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.

Frandsen, Mads Toudal; Sarkar, Subir

2010-01-01

98

Asymmetric dark matter and the Sun

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 5-10 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 can possibly be measured by the forthcoming SNO+ experiment.

Frandsen, Mads T

2010-01-01

99

Asymmetric Dark Matter and the Sun

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.

Frandsen, Mads T.; Sarkar, Subir

2010-07-01

100

Asymmetric Dark Matter and the Sun

International Nuclear Information System (INIS)

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.

2010-07-02

101

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)

1981-01-17

102

Correlations in Nuclear Matter

We analyze the nuclear matter correlation properties in terms of the pair correlation function. To this aim we systematically compare the results for the variational method in the Lowest Order Constrained Variational (LOCV) approximation and for the Bruekner-Hartree-Fock (BHF) scheme. A formal link between the Jastrow correlation factor of LOCV and the Defect Function (DF) of BHF is established and it is shown under which conditions and approximations the two approaches are equivalent. From the numerical comparison it turns out that the two correlation functions are quite close, which indicates in particular that the DF is approximately local and momentum independent. The Equations of State (EOS) of Nuclear Matter in the two approaches are also compared. It is found that once the three-body forces (TBF) are introduced the two EOS are fairly close, while the agreement between the correlation functions holds with or without TBF.

Baldo, M

2012-01-01

103

Spin polarized states in nuclear matter with Skyrme effective interaction

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...

Isayev, A A

2004-01-01

104

Possible Implications of Asymmetric Fermionic Dark Matter for Neutron Stars

Digital Repository Infrastructure Vision for European Research (DRIVER)

We consider the implications of fermionic asymmetric dark matter for a "mixed neutron star" composed of ordinary baryons and dark fermions. We find examples, where for a certain range of dark fermion mass -- when it is less than that of ordinary baryons -- such systems can reach higher masses than the maximal values allowed for ordinary ("pure") neutron stars. This is shown both within a simplified, heuristic Newtonian analytic framework with non-interacting particles and vi...

Goldman, I.; Mohapatra, R. N.; Nussinov, S.; Rosenbaum, D.; Teplitz, V.

2013-01-01

105

Constraining Asymmetric Dark Matter through observations of compact stars

DEFF Research Database (Denmark)

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.

Kouvaris, Christoforos; Tinyakov, Peter

2011-01-01

106

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)

1997-01-01

107

Hadronization in Nuclear Matter

Nuclei are unique analyzers of the space-time development of jets at early stage. We argue that the gluon bremsstrahlung, rather than the color string, is the main mechanism of hadronization of highly virtual quarks produced in a hard interaction. It results in an energy- and time-independent density of energy loss, like a color string, but steeply dependent on the quark virtuality. Effects of formation zone (FZ) and color transparency (CT) substantially affect the jet quenching in a nuclear matter. The latter also plays an important role in the broadening of transverse momentum distribution of a quark passing a nucleus. Parameter-free calculations provide a good description of available data on nuclear effects in the leading hadron production in deep-inelastic lepton scattering, back-to-back high-$p_T$ hadron pair production, broadening of the transverse momentum distribution in the Drell-Yan process of lepton pair production on nuclei.

Kopeliovich, B Z

1993-01-01

108

Possible implications of asymmetric fermionic dark matter for neutron stars

International Nuclear Information System (INIS)

We consider the implications of fermionic asymmetric dark matter (ADM) for a “mixed neutron star” composed of ordinary baryons and dark fermions. We find examples, where for a certain range of dark fermion mass – when it is less than that of ordinary baryons – such systems can reach higher masses than the maximal values allowed for ordinary (“pure”) neutron stars. This is shown both within a simplified, heuristic Newtonian analytic framework with non-interacting particles and via a general relativistic numerical calculation, under certain assumptions for the dark matter equation of state. Our work applies to various dark fermion models such as mirror matter models and to other models where the dark fermions have self-interactions

2013-10-01

109

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

2009-02-01

110

Vortical 'disks' of nuclear matter

International Nuclear Information System (INIS)

The basic equations for the vortical 'disks' of nuclear matter have been derived in the framework of nuclear hydrodynamics. The connection between the 'disk' stability problem and multifragmentation process is pointed out. 3 refs

1992-01-01

111

Nuclear Matter Equation of State and Three body Forces

The energy per particle, symmetry energy, pressure, Free energy are calculated for asymmetric nuclear matter using BHF approach and modern nucleon-nucleon CD-Bonn, Nijm1, Argonnev18 and Reid93 potentials. To obtain saturation in nuclear matter we add three-body interaction terms which are equivalent a la Skyrme to a density-dependent two-nucleon interaction. Good agreement is obtained in comparison with previous theoretical estimates and experimental data.

Mansour, Hesham M M

2011-01-01

112

Dense nuclear matter and symmetry energy in strong magnetic fields

Digital Repository Infrastructure Vision for European Research (DRIVER)

The properties of nuclear matter in the presence of a strong magnetic field, including the density-dependent symmetry energy, the chemical composition and spin polarizations, are investigated in the framework of the relativistic mean field models FSU-Gold. The anomalous magnetic moments (AMM) of the particles and the nonlinear isoscalar-isovector coupling are included. It is found that the parabolic isospin-dependence of the energy per nucleon of asymmetric nuclear matter re...

Dong, Jianmin; Lombardo, Umberto; Zuo, Wei; Zhang, Hongfei

2012-01-01

113

Nuclear matter and electron scattering

Energy Technology Data Exchange (ETDEWEB)

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.)

Sick, I. [Dept. fuer Physik und Astronomie, Univ. Basel (Switzerland)

1998-06-01

114

Bound states in nuclear matter

International Nuclear Information System (INIS)

Full text: The formation of bound states in dilute nuclear matter will be discussed and its implications for the equation of state and composition of astrophysical plasma in supernova envelopes. Bulk properties of dense nuclear and hypernuclear matter will be discussed in the framework of the Brueckner theory. (author)

2009-01-18

115

Giant resonances and nuclear matter

International Nuclear Information System (INIS)

We discuss the relation between the frequencies of the giant resonances observed in nuclei and the properties of nuclear matter. We show in particular that the recent experimental identification of the giant monopole resonance provides information on the compressibility of nuclear matter. We compare the properties of the compression mode of a nucleus to those of surface modes

1980-02-09

116

Nuclear matter equations of state for the practitioner

International Nuclear Information System (INIS)

The nuclear equation of state (Egos) is reviewed for cases allowing analytical formulas. Various EOS models designed for symmetric nuclear matter (SNM) and asymmetric nuclear matter (ANM) are compared with respect to their predictions regarding the binding energy and nuclear incompressibility. The discussion is then extended to finite nuclei where information about the EOS can be extracted from the centroids of the Giant Monopole Resonance. Finally, consideration is given to the nuclear EOS under extreme conditions of density, such as those encountered in intermediate heavy ion collisions or in astrophysics (neutron stars or supernovas). (author)

2007-01-01

117

Condensed Matter Nuclear Science

Preface -- 1. General. Progress in condensed matter nuclear science / A. Takahashi. Summary of ICCF-12 / X. Z. Li. Overview of light water/hydrogen-based low-energy nuclear reactions / G. H. Miley and P. J. Shrestha -- 2. Excess heat and He detection. Development of "DS-reactor" as the practical reactor of "cold fusion" based on the "DS-cell" with "DS-cathode" / Y. Arata and Y.-C. Zhang. Progress in excess of power experiments with electrochemical loading of deuterium in palladium / V. Violante ... [et al.]. Anomalous energy generation during conventional electrolysis / T. Mizuno and Y. Toriyabe. "Excess heat" induced by deuterium flux in palladium film / B. Liu ... [et al.]. Abnormal excess heat observed during Mizuno-type experiments / J.-F. Fauvarque, P. P. Clauzon and G. J.-M. Lallevé. Seebeck envelope calorimetry with a Pd|D[symbol]O + H[symbol]SO[symbol] electrolytic cell / W.-S. Zhang, J. Dash and Q. Wang. Observation and investigation of nuclear fusion and self-induced electric discharges in liquids / A. I. Koldamasov ... [et al.]. Description of a sensitive seebeck calorimeter used for cold fusion studies / E. Storms. Some recent results at ENEA / M. Apicella ... [et al.]. Heat measurement during plasma electrolysis / K. Iizumi ... [et al.]. Effect of an additive on thermal output during electrolysis of heavy water with a palladium cathode / Q. Wang and J. Dash. Thermal analysis of calorimetric systems / L. D'Aulerio ... [et al.]. Surface plasmons and low-energy nuclear reactions triggering / E. Castagna ... [et al.]. Production method for violent TCB jet plasma from cavity / F. Amini. New results and an ongoing excess heat controversy / L. Kowalski ... [et al.] -- 3. Transmutation. Observation of surface distribution of products by X-ray fluorescence spectrometry during D[symbol] gas permeation through Pd Complexes / Y. Iwamura ... [et al.]. Discharge experiment using Pd/CaO/Pd multi-layered cathode / S. Narita ... [et al.]. Producing transmutation element on multi-layered Pd sample by deuterium permeation / H. Yamada ... [et al.]. Experimental observation and combined investigation of high-performance fusion of iron-region isotopes in optimal growing microbiological associations / V. I. Vysotskii ... [et al.]. Research into low-energy nuclear reactions in cathode sample solid with production of excess heat, stable and radioactive impurity nuclides / A. B. Karabut. Influence of parameters of the glow discharge on change of structure and the isotope composition of the cathode materials / I. B. Savvatimova and D. V. Gavritenkov. Elemental analysis of palladium electrodes after Pd/Pd light water critical electrolysis / Y. Toriyabe ... [et al.]. Progress on the study of isotopic composition in metallic thin films undergone to electrochemical loading of hydrogen / M. Apicella ... [et al.]. In situ accelerator analyses of palladium complex under deuterium permeation / A. Kitamura ... [et al.]. High-resolution mass spectrum for deuterium (hydrogen) gas permeating palladium film / Q. M. Wei ... [et al.]. ICP-MS analysis of electrodes and electrolytes after HNO[symbol]/H[symbol]O electrolysis / S. Taniguchi ... [et al.]. The Italy-Japan project - fundamental research on cold transmutation process for treatment of nuclear wastes / A. Takahashi, F. Celani and Y. Iwamura -- 4. Nuclear physics approach. Reproducible nuclear emissions from Pd/PdO:Dx heterostructure during controlled exothermic deuterium desorption / A. G. Lipson ... [et al.]. Correct identification of energetic alpha and proton tracks in experiments on CR-39 charged particle detection during hydrogen desorption from Pd/PdO:H[symbol] heterostructure / A. S. Roussetski ... [et al.]. Intense non-linear soft X-ray emission from a hydride target during pulsed D bombardment / G. H. Miley ... [et al.]. Enhancement of first wall damage in ITER type TOKAMAK due to LENR effects / A. G. Lipson, G. H. Miley and H. Momota. Generation of DD-reactions in a ferroelectric KD[symbol]PO[symbol] single crystal during transition

Takahashi, Akito; Ota, Ken-Ichiro; Iwamura, Yashuhiro

118

Covariant density functional theory for nuclear matter

Energy Technology Data Exchange (ETDEWEB)

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.)

Badarch, U.

2007-07-01

119

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.

2012-01-01

120

Chiral thermodynamics of nuclear matter

Energy Technology Data Exchange (ETDEWEB)

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.

Fiorilla, Salvatore

2012-10-23

121

Phase transitions in nuclear matter

International Nuclear Information System (INIS)

The rather general circumstances under which a phase transition in hadronic matter at finite temperature to an abnormal phase in which baryon effective masses become small and in which copious baryon-antibaryon pairs appear is emphasized. A preview is also given of a soliton model of dense matter, in which at a density of about seven times nuclear density, matter ceases to be a color insulator and becomes increasingly color conducting. 22 references

1984-10-08

122

Shear viscosity of nuclear matter

In this talk I report my recent study on the shear viscosity of neutron-rich nuclear matter from a relaxation time approach. An isospin- and momentum-dependent interaction is used in the study. Effects of density, temperature, and isospin asymmetry of nuclear matter on its shear viscosity have been discussed. Similar to the symmetry energy, the symmetry shear viscosity is defined and its density and temperature dependence are studied.

Xu, Jun

2013-01-01

123

Flavor and Collider Signatures of Asymmetric Dark Matter

We consider flavor constraints on, and collider signatures of, Asymmetric Dark Matter (ADM) via higher dimension operators. In the supersymmetric models we consider, R-parity violating (RPV) operators carrying B-L interact with n dark matter (DM) particles X through an interaction of the form W = X^n O_{B-L}, where O_{B-L} = q l d^c, u^c d^c d^c, l l e^c. This interaction ensures that the lightest ordinary supersymmetric particle (LOSP) is unstable to decay into the X sector, leading to a higher multiplicity of final state particles and reduced missing energy at a collider. Flavor-violating processes place constraints on the scale of the higher dimension operator, impacting whether the LOSP decays promptly. While the strongest limitations on RPV from n-\\bar{n} oscillations and proton decay do not apply to ADM, we analyze the constraints from meson mixing, mu-e conversion, mu -> 3 e and b -> s l^+ l^-. We show that these flavor constraints, even in the absence of flavor symmetries, allow parameter space for pr...

Kim, Ian-Woo

2014-01-01

124

Indirect Detection Signatures for the Origin of Asymmetric Dark Matter

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 ${\\cal O}_{ADM} = X {\\cal O}_{B-L}/M^2$, where ${\\cal O}_{B-L} = u^c d^c d^c,~\\ell \\ell e^c,~q \\ell d^c$ (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 the low energy gamma ray data from Fermi. For heavy ADM, we consider $\\gamma$-rays and proton...

Zhao, Yue

2014-01-01

125

Dipole collectivity and reflection asymmetric nuclear shapes

International Nuclear Information System (INIS)

Collective dipole bands observed in light and heavy nuclei, are characterized experimentally by states of alternating parities and enhanced E1 decays. Such states arise from an intrinsic state which is reflection asymmetric and, therefore, is not invariant under the parity operation. This state may correspond to any configuration that is reflection asymmetric (e.g cluster state, or stable octupole deformed state). Dipole collective states have been observed in /sup 18/O and the Ra-Th region. The experimental signatures for dipole collectivity in these nuclei are discussed, and similarity and differences between the cluster model and stable octupole shape model are discussed. Search for such states in other regions of the chart of nuclei are proposed

1986-01-01

126

Energy Technology Data Exchange (ETDEWEB)

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.)

Heiselberg, H. [NORDITA, Copenhagen (Denmark)

1998-06-01

127

Nuclear matter: new states of dense matter

International Nuclear Information System (INIS)

Heavy ion collisions when involving incident ion velocity of about a quarter of light speed are powerful tools for understanding the behaviour of nuclear matter. Hot nuclei produced in such collisions decay either by evaporation (emission of particles) or by multifragmentation (production of smaller nuclei) or by vaporization (production of particles and light nuclei). These decay processes show strong analogies with liquid-gas transition. 2 new experimental facts support this interpretation: energy fluctuations and abnormal correlations. In the first case fluctuations show the existence of negative heat capacity and in the second case correlations show the possibility of a spinodal decomposition that was, till now only speculated for liquid-gas transitions. (A.C.)

2001-01-01

128

International Nuclear Information System (INIS)

A comprehensive review is presented dealing with pion excitations and condensation in nucleon matter. A discussion of the behavior of bosons in scalar electric and nuclear fields is given along with a consideration of the possible existence of superdense and supercharged nuclei. The applications to nuclei and neutron stars are given

1978-01-01

129

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.)

1995-01-16

130

We study a nonlinear nuclear equation of state in the framework of a relativistic mean field theory. We investigate the possible thermodynamic instability in a warm and dense asymmetric nuclear medium where a phase transition from nucleonic matter to resonance dominated ? matter can take place. Such a phase transition is characterized by both mechanical instability (fluctuations on the baryon density) and by chemical-diffusive instability (fluctuations on the isospin concentration) in asymmetric nuclear matter. Similarly to the liquid-gas phase transition, the nucleonic and the ?-matter phase have a different isospin density in the mixed phase. In the liquid-gas phase transition, the process of producing a larger neutron excess in the gas phase is referred to as isospin fractionation. A similar effects can occur in the nucleon-? matter phase transition due essentially to a negative ?-particles excess in asymmetric nuclear matter. In this context, we investigate also the effects of power law effects, due to the possible presence of nonextensive statistical mechanics effects.

Lavagno, A.; Gervino, G.; Pigato, D.

2014-03-01

131

We report a combined experimental (H (Rydberg) atom photofragment translational spectroscopy) and theoretical (ab initio electronic structure and vibronic coupling calculations) study of the effects of symmetry on the photodissociation dynamics of phenols. Ultraviolet photoexcitation to the bound S1((1)??*) state of many phenols leads to some O-H bond fission by tunneling through the barrier under the conical intersection (CI) between the S1 and dissociative S2((1)??*) potential energy surfaces in the R(O-H) stretch coordinate. Careful analysis of the total kinetic energy release spectra of the resulting products shows that the radicals formed following S1 ? S0 excitation of phenol and symmetrically substituted phenols like 4-fluorophenol all carry an odd number of quanta in vibrational mode ?(16a), whereas those deriving from asymmetrically substituted systems like 3-fluorophenol or 4-methoxyphenol do not. This contrasting behavior can be traced back to symmetry. Symmetrically substituted phenols exist in two equivalent rotamers, which interconvert by tunneling through the barrier to OH torsional motion. Their states are thus best considered in the non-rigid G4 molecular symmetry group, wherein radiationless transfer from the S1 to S2 state requires a coupling mode of a2 symmetry. Of the three a2 symmetry parent modes, the out-of-plane ring puckering mode ?(16a) shows much the largest interstate coupling constant in the vicinity of the S1/S2 CI. The nuclear motions associated with ?(16a) are orthogonal to the dissociation coordinate, and are thus retained in the radical products. Introducing asymmetry (even a non-linear substituent in the 4-position) lifts the degeneracy of the rotamers, and lowers the molecular symmetry to Cs. Many more parent motions satisfy the reduced (a'') symmetry requirement to enable S1/S2 coupling, the most effective of which is OH torsion. This motion 'disappears' on O-H bond fission; symmetry thus imposes no restriction to forming radical products with vibrational quantum number v = 0. The present work yields values for the O-H bond strengths in 3-FPhOH and 4-MeOPhOH, and recommends modest revisions to the previously reported O-H bond strengths in other asymmetrically substituted phenols like 3- and 2-methylphenol and 4-hydroxyindole. PMID:24201655

Karsili, Tolga N V; Wenge, Andreas M; Marchetti, Barbara; Ashfold, Michael N R

2014-01-14

132

Asymmetric dark matter annihilation as a test of non-standard cosmologies

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.

Gelmini, Graciela B; Rehagen, Thomas

2013-01-01

133

Isospin dependence of nuclear matter symmetry energy coefficients

Digital Repository Infrastructure Vision for European Research (DRIVER)

Generalized symmetry energy coefficients of asymmetric nuclear matter are obtained as screening functions. The dependence of the isospin symmetry energy coefficient on the neutron proton (n-p) asymmetry may be determined unless by a constant (exponent) $Z$ which depend on microscopic properties. The dependence of the generalized symmetry energy coefficients with Skyrme forces on the n-p asymmetry and on the density, only from .5 up to 1.5 $\\rho_0$, are investigated in the is...

Braghin, Fabio L.

2001-01-01

134

Probing nuclear matter with jets

International Nuclear Information System (INIS)

Jet physics in relativistic heavy ion collisions, which combines perturbative QCD jet production with quark and gluon energy loss and in-medium parton shower modification, has emerged as a powerful tool to probe the properties of strongly-interacting matter formed in high-energy nuclear reactions. We present selected results for the modification of jet cross sections and related observables in the ambiance of hot and/or dense nuclear medium. We focus on the inclusive jet spectrum and dijets [O(?s3)], and Z0/?? tagged jets [O(GF?s2)] in the framework of perturbative QCD

2013-08-01

135

Chiral Dynamics and Nuclear Matter

Digital Repository Infrastructure Vision for European Research (DRIVER)

We calculate the equation of state of isospin-symmetric nuclear matter in the three-loop approximation of chiral perturbation theory. The contributions to the energy per particle $\\bar E(k_f)$ from one- and two-pion exchange diagrams are ordered in powers of the Fermi momentum $k_f$ (modulo functions of $k_f /m_\\pi$). It is demonstrated that, already at order ${\\cal O}(k_f^4)$, two-pion exchange produces realistic nuclear binding. The underlying saturation mechanism is surpr...

Kaiser, N.; Fritsch, S.; Weise, W.

2001-01-01

136

Temperature Dependent Nuclear Matter Approach

International Nuclear Information System (INIS)

Full text: The nuclear matter approach provides an effective interaction in the presence of a sea of nucleons. Especially it accounts for the Pauli principle which forbids scattering processes into the occupied states of the nucleonic see. It is well suited to describe the bulk properties of nuclei as well as optical potentials beyond 40 MeV incident energy. Difficulties in the description of nucleon-nucleus reactions beyond 70 MeV may indicate the importance of excited doorway states for reaction processes and therefore the optical potentials. In this contribution we consider the g-matrix approach for excited nuclear matter. The g-matrix is evaluated via the Bethe-Goldstone equation with an exact Pauli operator accounting for excitations with arbitrary occupation distributions. The features of the g-matrix with regard to changes in excitation are discussed. (author)

2010-09-06

137

Periodic structure in nuclear matter

International Nuclear Information System (INIS)

The properties of nuclear matter are studied in the framework of the quantumhadrodynamics. Assuming an ?-meson field, periodic in space, a self-consistent set of equations is derived in mean field approximation for the description of nucleons interacting via ?-meson and ?-meson fields. Solutins of these self-consistent equations have been found: the baryon density is constant in space, however the baryon current density is periodic. This high density phase of nuclear matter can be produced by anisotropic external pressure, occurring e.g. in relativistic heavy ion reactions. The self-consistent fields developing beyond the instability limit have a special screw symmetry. In the presence of such an ? field the energy spectrum of the relativistic nucleons exhibits allowed and forbidden bands similarly to the energy spectrum of the electrons in solids. (author) 15 refs.; 8 figs.; 1 tab

1992-01-01

138

Deuteron formation in nuclear matter

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ene...

Kuhrts, C.; Beyer, M.; Roepke, G.

1999-01-01

139

Variational theory of nuclear matter

International Nuclear Information System (INIS)

The variational theory of nuclear matter is reviewed with especial reference to the powerful diagrammatic techniques invented in recent years. The subject is considered under the headings; general cluster expansion theory, the Jastrow energy expectation value, comparison of Jastrow and Brueckner=Bethe theories in low orders, diagrammatic cluster expansions, Fermi hypernetted-chain (FHNC) methods, FHNC calculations for central potentials, state-dependent correlations. 202 references. (UK)

1979-01-01

140

Chemical and mechanical instability in warm and dense nuclear matter

We investigate the possible thermodynamic instability in a warm and dense nuclear medium (T<50 MeV and \\rho_0<\\rho_B< 3\\rho_0) where a phase transition from nucleonic matter to resonance-dominated Delta-matter can take place. The analysis is performed by requiring the global conservation of baryon and electric charge numbers in the framework of a relativistic equation of state. Similarly to the liquid-gas phase transition, we show that the nucleon-Delta matter phase transition is characterized by both mechanical instability (fluctuations on the baryon density) and by chemical-diffusive instability (fluctuations on the charge concentration) in asymmetric nuclear matter. We then perform an investigation and a comparative study on the different nature of such instabilities and phase transitions.

Lavagno, A; 10.1103/PhysRevC.86.024917

2012-01-01

141

Asymmetric WIMP Dark Matter in the presence of DM/anti-DM Oscillations

Digital Repository Infrastructure Vision for European Research (DRIVER)

The class of `Asymmetric Dark Matter' scenarios relies on the existence of a primordial particle/anti-particle asymmetry in the dark sector related to the baryon asymmetry as a way to address the observed similarity between the baryonic and dark matter energy densities today. Focusing on this framework we calculate the evolution of the dark matter relic abundance in the presence of particle/anti-particle oscillations. We show how oscillations re-open the parameter space of a...

Zaharijas, Gabrijela

2012-01-01

142

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)

2006-01-01

143

Baryogenesis and Asymmetric Dark Matter from The Left-Right Mirror Symmetric Model

The paper suggests a left-right mirror symmetric model to account for the baryogenesis and asymmetric dark matter. The model can simultaneously accommodate the standard model, neutrino physics, matter-antimatter asymmetry and dark matter. In particular, it naturally and elegantly explains the origin of the baryon and dark matter asymmetries, and clearly gives the close interrelations of them. In addition, the model predicts a number of interesting results, e.g. the cold dark matter neutrino mass is $3.1$ times the proton mass. It is also feasible and promising to test the model in future experiments.

Yang, Wei-Min

2014-01-01

144

Reflection-asymmetric nuclear deformations within the Density Functional Theory

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.

Olsen, E; Nazarewicz, W; Stoitsov, M; 10.1088/1742-6596/402/1/012034

2013-01-01

145

On the nuclear stopping in asymmetric colliding nuclei

Using an isospin-dependent quantum molecular dynamics (IQMD) model, nuclear stopping is analyzed in asymmetric colliding channels by keeping the total mass fixed. The calculations have been carried by varying the asymmetry of the colliding pairs with different neutron-proton ratios in center of mass energy 250 MeV/nucleon and by switching off the effect of Coulomb interactions. We find sizable effect of asymmetry of colliding pairs on the stopping and therefore on the equilibrium reached in a reaction.

Kaur, Varinderjit; Puri, Rajeev K

2010-01-01

146

Probing nuclear matter with jets

Energy Technology Data Exchange (ETDEWEB)

Jet physics in relativistic heavy ion collisions, which combines perturbative QCD jet production with quark and gluon energy loss and in-medium parton shower modification, has emerged as a powerful tool to probe the properties of strongly-interacting matter formed in high-energy nuclear reactions. We present selected results for the modification of jet cross sections and related observables in the ambiance of hot and/or dense nuclear medium. We focus on the inclusive jet spectrum and dijets [O(?{sub s}{sup 3})], and Z{sup 0}/?{sup ?} tagged jets [O(G{sub F}?{sub s}{sup 2})] in the framework of perturbative QCD.

Zhang, Ben-Wei, E-mail: bwzhang@iopp.ccnu.edu.cn [Key Laboratory of Quark and Lepton Physics (MOE) and Institute of Particle Physics, Central China Normal University, Wuhan 430079 (China); He, Yuncun [Key Laboratory of Quark and Lepton Physics (MOE) and Institute of Particle Physics, Central China Normal University, Wuhan 430079 (China); Neufeld, R.B.; Vitev, Ivan [Los Alamos National Laboratory, Theoretical Division, MS B238, Los Alamos, NM 87545 (United States); Wang, Enke [Key Laboratory of Quark and Lepton Physics (MOE) and Institute of Particle Physics, Central China Normal University, Wuhan 430079 (China)

2013-08-15

147

Quantum hadrodynamics and nuclear matter

International Nuclear Information System (INIS)

The properties of infinite nuclear matter are studied in the model relativistic quantum field theory of Walecka. Neutral scalar and vector meson exchange reproduces the basic Lorentz structure of the observed nucleon-nucleon interaction, and the consequences of this structure are studied in detail. In the mean-field approximation, nuclear saturation involves a cancellation between large attractive and repulsive components in the average potential energy. The attractive scalar field decreases the nucleon mass significantly, and the strong vector repulsion implies a stiff high-energy equation of state. Corrections to the mean-field approach arising from vacuum fluctuations, self-consistent nucleon exchange, and two-nucleon correlations are examined. These have a small effect on the condensed meson fields but may produce significant changes in the binding energy. Corrections to the mean-field equation of state are small at high density

1984-02-20

148

Nuclear interactions and hadronic matter

International Nuclear Information System (INIS)

The new generation of heavy ion accelerators and complex experimental devices, developed in the last two decades, give access to new information concerning the dynamics of nuclear collisions and allow to obtain and study in the laboratory the nuclear matter under extreme conditions of density and temperature. Of special interest is the intermediate energy region where the reactions are dominated by the competition between the mean field and nucleon-nucleon interaction. Fundamental aspects of nuclear reaction studies are probed at different instants of a nuclear collision. One can learn about the transport properties of nuclear matter in pure nucleonic regime and understand the modification of the nucleon-nucleon cross section due to various in-medium effects: density effects, effective mass, quantum effects, three-body interactions. With increasing energy, fast particle emission associated with direct nucleon-nucleon collisions in the first steps of the reaction come into play too. At higher energy, flow measurements are crucial tests of the influence of medium effects by probing the elastic part of the nucleon-nucleon collisions. On the other side, at higher incident energies, the characteristics of the nuclear equation of state (EoS) can be studied if local thermal and chemical equilibrium turns out to be established. Understanding of the properties of the nuclear matter in extreme conditions is a fundamental goal. The EoS is also an essential ingredient in the description of the massive stars leading to supernova explosion and neutron star formation. Experimental studies of such aspects needs experimental devices of high complexity which can detect and identify event by event all products coming out from heavy ion interactions at intermediate, relativistic and ultra-relativistic energies, having as complete as possible information on their mass, charge, velocity vector. CHIMERA and FOPI are such devices for intermediate and relativistic energy, respectively. Our group had contributions in their design, construction, operation, calibration and data analysis, part of these activities being the subject of our project financed by CERES National Program. CHIMERA being a new detector, for its calibration in energy, charge and mass of the identified particles, quite large efforts were dedicated for developing consistent calibration procedures. Based on these, correct Data Summary Tapes (DST) are currently produced and analysis activities will start in the near future. Concerning the FOPI detector, our group concentrated in extracting detailed information on the collective phenomena in central and mid-central symmetric heavy ion collisions in the energy range of 90 AMeV - 400 AMeV. We shown that such observables are sensitive to the EoS and the comparison with model calculations evidenced that at such energies a soft EoS could explain the observed experimental trends. Another subject followed up by our group is related to the dependence of the squeeze-out phenomena on the N/Z content of the spectator matter. Such studies could be decisive for extracting the in-medium isospin dependence of the nucleon-nucleon cross section. (authors)

2002-12-02

149

Hot Nuclear Matter A Variational Approach

We develop a nonperturbative technique in field theory to study properties of infinite nuclear matter at zero temperature as well as at finite temperatures. Here we dress the nuclear matter with off-mass shell pions. The techniques of thermofield dynamics are used for finite temperature calculations. Equation of state is derived from the dynamics of the interacting system in a self consistent manner. The transition temperature for nuclear matter appears to be around 15 MeV.

Mishra, H; Panda, P K; Parida, B K

1992-01-01

150

Asymmetric WIMP Dark Matter in the presence of DM/anti-DM Oscillations

The class of `Asymmetric Dark Matter' scenarios relies on the existence of a primordial particle/anti-particle asymmetry in the dark sector related to the baryon asymmetry as a way to address the observed similarity between the baryonic and dark matter energy densities today. Focusing on this framework we calculate the evolution of the dark matter relic abundance in the presence of particle/anti-particle oscillations. We show how oscillations re-open the parameter space of asymmetric dark matter models, in particular in the direction of allowing large (WIMP-scale) DM masses. Finally, we constrain the parameter space in this framework by applying up-to-date bounds from indirect detection signals on annihilating DM.

Zaharijas, Gabrijela

2013-01-01

151

Neutron drip line and the equation of state of nuclear matter

Digital Repository Infrastructure Vision for European Research (DRIVER)

We investigate how the neutron drip line is related to the density dependence of the symmetry energy, by using a macroscopic nuclear model that allows us to calculate nuclear masses in a way dependent on the equation of state of asymmetric nuclear matter. The neutron drip line obtained from these masses is shown to appreciably shift to a neutron-rich side in a nuclear chart as the density derivative of the symmetry energy increases. Such shift is clearly seen for light nucle...

Oyamatsu, Kazuhiro; Iida, Kei; Koura, Hiroyuki

2010-01-01

152

Towards the nuclear matter - quark matter phase transition

International Nuclear Information System (INIS)

The conjectured first order phase transition from cold nuclear to cold quark matter is considered. It is found that non-perturbative effects due to instantons may have a 'smoothing-out' effect on the transition. (author)

1980-01-01

153

Structure of the subsaturated nuclear matter

Energy Technology Data Exchange (ETDEWEB)

Quantum molecular dynamics is applied to study the ground state and excited state properties of nuclear matter at subsaturation densities. The structure of nuclear matter at subsaturation density shows some exotic shapes with variation of the density. However, the structure in our result is rather irregular compared to those of previous works due to the existence of local minimum configurations. (author)

Maruyama, Toshiki; Maruyama, Tomoyuki; Chiba, Satoshi; Iwamoto, Akira [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Niita, Koji; Oyamatsu, Kazuhiro

1998-07-01

154

Digital Repository Infrastructure Vision for European Research (DRIVER)

$\\phi$-meson mass in nuclear matter ($m_{\\phi}^*$) is investigated using an effective Lagrangian of $\\phi$ interacting with octet baryons. $m_{\\phi}^*$ decreases by a few \\% in nuclear matter due to the current conservation and effective nucleon/hyperon masses. Its implication to the p-A and A-A collisions are briefly discussed.

Kuwabara, H.; Hatsuda, T.

1995-01-01

155

Holographic Symmetry Energy of the Nuclear Matter

Digital Repository Infrastructure Vision for European Research (DRIVER)

We calculate the symmetry energy of the nuclear matter by using the bottom-up approach, so called hard wall model. To consider the nuclear matter, we introduce the isospin for u- and d-quarks. We find that in the hard wall model, the symmetry energy of the nuclear matter is proportional to the square of nucleon density. We also study the symmetry energy of the quark matter in the deconfining phase. Finally, we investigate the effect of the symmetry energy on the Hawking-Page...

Park, Chanyong

2011-01-01

156

Light asymmetric dark matter from new strong dynamics

A ˜5GeV “dark baryon” with a cosmic asymmetry similar to that of baryons is a natural candidate for the dark matter. We study the possibility of generating such a state through dynamical electroweak symmetry breaking, and show that it can share the relic baryon asymmetry via sphaleron interactions, even though it has no electroweak interactions. The scattering cross section on nucleons, estimated in analogy to QCD, is within reach of underground direct detection experiments.

Frandsen, Mads T.; Sarkar, Subir; Schmidt-Hoberg, Kai

2011-09-01

157

A new effective Lagrangian for nuclear matter

The relativistic mean field model, the Zimányi - Moszkowski (ZM) Lagrangian describes nuclear matter and stable finite nuclei even in the non-relativistic limit. It fails, however, to predict the correct non-relativistic spin-orbit (SO) coupling. In this paper we improve on this matter by an additional tensor coupling analogous to the anomalous gyromagnetic ratio. It can be adjusted to describe the SO-term without changing the mean field solution of the ZM-Lagrangian for nuclear matter.

Biro, T S

1997-01-01

158

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.)

1987-01-01

159

Interacting nuclear matter in a slab system

International Nuclear Information System (INIS)

The polarization propagator for a slab of interacting nuclear matter is calculated in the Random Phase Approximation (RPA). The zero range interaction between nucleons is assumed. 6 refs., 6 figs. (author)

1989-01-01

160

Light Asymmetric Dark Matter on the Lattice: SU(2) Technicolor with Two Fundamental Flavors

DEFF Research Database (Denmark)

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.

Lewis, Randy; Pica, Claudio

2012-01-01

161

Dilepton radiation from high temperature nuclear matter

Energy Technology Data Exchange (ETDEWEB)

The general features of electron-positron emission from high temperature nuclear matter are discussed. Estimates are made of the production rates arising from incoherent nucleon-nucleon scattering and from two-pion annihilation. It may be possible to infer the pion dispersion relation in hot and dense nuclear matter by measuring the invariant mass distribution of back-to-back electrons and positrons in the center of mass frame in high energy nucleus-nucleus collisions.

Gale, C.; Kapusta, J.

1987-06-01

162

Nuclear matter with JISP16 NN interaction

Saturation properties of the JISP16 NN interaction are studied in symmetric nuclear matter calculations, with special attention paid to the convergence properties with respect to the number of partial waves. We also present results of pure neutron matter calculations with the JISP16 interaction.

Shirokov, A M; Vary, J P; Bogner, S K; Mazur, A I; Mazur, E A; Gogny, D

2014-01-01

163

Dense nuclear matter and symmetry energy in strong magnetic fields

International Nuclear Information System (INIS)

The properties of nuclear matter in the presence of a strong magnetic field, including the density-dependent symmetry energy, the chemical composition and spin polarizations, are investigated in the framework of the relativistic mean field models FSUGold. The anomalous magnetic moments (AMM) of the particles and the nonlinear isoscalar–isovector coupling are included. It is found that the parabolic isospin dependence of the energy per nucleon of asymmetric nuclear matter remains valid for the values of magnetic field below 105Bce, Bce=4.414×1013 G being the electron critical field. Accordingly, the symmetry energy can be obtained by the difference of the energy per nucleon in pure neutron matter and that in symmetric matter. The symmetry energy, which is enhanced by the presence of the magnetic field, significantly affects the chemical composition and the proton polarization. The effects of the AMM of each component on the energy per nucleon, symmetry energy, chemical composition and spin polarization are discussed in detail

2013-01-17

164

Dense nuclear matter and symmetry energy in strong magnetic fields

The properties of nuclear matter in the presence of a strong magnetic field, including the density-dependent symmetry energy, the chemical composition and spin polarizations, are investigated in the framework of the relativistic mean field models FSU-Gold. The anomalous magnetic moments (AMM) of the particles and the nonlinear isoscalar-isovector coupling are included. It is found that the parabolic isospin-dependence of the energy per nucleon of asymmetric nuclear matter remains valid for values of the magnetic field below $10^{5}B_{c}^{e}$, $B_{c}^{e}=4.414\\times10^{13}$G being the electron critical field. Accordingly, the symmetry energy can be obtained by the difference of the energy per nucleon in pure neutron matter and that in symmetric matter. The symmetry energy, which is enhanced by the presence of the magnetic field, significantly affects the chemical composition and the proton polarization. The effects of the AMM of each component on the energy per nucleon, symmetry energy, chemical composition an...

Dong, Jianmin; Zuo, Wei; Zhang, Hongfei

2012-01-01

165

Dense nuclear matter and symmetry energy in strong magnetic fields

Energy Technology Data Exchange (ETDEWEB)

The properties of nuclear matter in the presence of a strong magnetic field, including the density-dependent symmetry energy, the chemical composition and spin polarizations, are investigated in the framework of the relativistic mean field models FSUGold. The anomalous magnetic moments (AMM) of the particles and the nonlinear isoscalar–isovector coupling are included. It is found that the parabolic isospin dependence of the energy per nucleon of asymmetric nuclear matter remains valid for the values of magnetic field below 10{sup 5}B{sub c}{sup e}, B{sub c}{sup e}=4.414×10{sup 13} G being the electron critical field. Accordingly, the symmetry energy can be obtained by the difference of the energy per nucleon in pure neutron matter and that in symmetric matter. The symmetry energy, which is enhanced by the presence of the magnetic field, significantly affects the chemical composition and the proton polarization. The effects of the AMM of each component on the energy per nucleon, symmetry energy, chemical composition and spin polarization are discussed in detail.

Dong, Jianmin, E-mail: dongjm07@lzu.cn [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Lombardo, Umberto [Dipartimento di Fisica and INFN-LNS, Via S. Sofia 64, I-95123 Catania (Italy); Zuo, Wei, E-mail: zuowei@impcas.ac.cn [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Zhang, Hongfei [School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000 (China)

2013-01-17

166

Past and present of nuclear matter

Energy Technology Data Exchange (ETDEWEB)

The subject of nuclear matter is interesting for many fields of physics ranging from condensed matter to lattice QCD. Knowing its properties is important for our understanding of neutron stars, supernovae and cosmology. Experimentally, we have the most precise information on ground state nuclear matter from the mass formula and from the systematics of monopole vibrations. This gives us the ground state density, binding energy and the compression modulus k at ground state density. However, those methods can not be extended towards the regime we are most interested in, the regime of high density and high temperature. Additional information can be obtained from the observation of neutron stars and of supernova explosions. In both cases information is limited by the rare events that nature provides for us. High energy heavy ion collisions, on the other hand, allow us to perform controlled experiments in the laboratory. For a very short period in time we can create a system that lets us study nuclear matter properties. Density and temperature of the system depend on the mass of the colliding nuclei, on their energy and on the impact parameter. The system created in nuclear collisions has at best about 200 constituents not even close to infinite nuclear matter, and it lasts only for collision times of {approx} 10{sup {minus}22}sec, not an ideal condition for establishing any kind of equilibrium. Extended size and thermal and chemical equilibrium, however, axe a priori conditions of nuclear matter. As a consequence we need realistic models that describe the collision dynamics and non-equilibrium effects in order to relate experimental observables to properties of nuclear matter. The study of high energy nuclear collisions started at the Bevalac. I will try to summarize the results from the Bevalac studies, the highlights of the continuing program, and extension to higher energies without claiming to be complete.

Ritter, H.G.

1994-05-01

167

Dark Matter Studies Entrain Nuclear Physics

We review theoretically well-motivated dark-matter candidates, and pathways to their discovery, in the light of recent results from collider physics, astrophysics, and cosmology. Taken in aggregate, these encourage broader thinking in regards to possible dark-matter candidates --- dark-matter need not be made of "WIMPs," i.e., elementary particles with weak-scale masses and interactions. Facilities dedicated to nuclear physics are well-poised to investigate certain non-WIMP models. In parallel to this, developments in observational cosmology permit probes of the relativistic energy density at early epochs and thus provide new ways to constrain dark-matter models, provided nuclear physics inputs are sufficiently well-known. The emerging confluence of accelerator, astrophysical, and cosmological constraints permit searches for dark-matter candidates in a greater range of masses and interaction strengths than heretofore possible.

Gardner, Susan

2013-01-01

168

Nuclear matter in neutron star crust

International Nuclear Information System (INIS)

Properties of nuclear matter below the nuclear saturation density is analyzed by numerical simulations with the periodic boundary condition. The equation of state at these densities is softened by the formation of cluster(s) internal density of which is nearly equal to the saturation density. The structure of nuclear matter shows some exotic shapes with variation of the density. Furthermore, it is found that the symmetry parameter a_s_y_m(?) is not a linear function of density at low density region. (author)

2000-01-01

169

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

1985-09-16

170

On phase transitions of nuclear matter in the Nambu-Jona-Lasinio model

International Nuclear Information System (INIS)

Within the Cornwall-Jackiw-Tomboulis (CJT) approach a general formalism is established for the study of asymmetric nuclear matter (ANM) described by Nambu-Jona-Lasinio (NJL) model. Restricting to the double-bubble approximation (DBA) we determine the bulk properties of ANM. Restricting to the double-bubble approximation (DBA) we determine the bulk properties of ANM, in particular, the density dependence of the nuclear symmetry energy, which is in good agreement with data of recent analyses. (author)

2011-06-01

171

Nuclear Pasta Matter for Different Proton Fractions

Nuclear matter under astrophysical conditions is explored with time-dependent and static Hartree-Fock calculations. The focus is in a regime of densities where matter segregates into liquid and gaseous phases unfolding a rich scenario of geometries, often called nuclear pasta shapes (e.g. spaghetti, lasagna). Particularly the appearance of the different phases depending on the proton fraction and the transition to uniform matter are investigated. In this context the neutron background density is of special interest, because it plays a crucial role for the type of pasta shape which is built. The study is performed in two dynamical ranges, one for hot matter and one at temperature zero to investigate the effect of cooling.

Schütrumpf, B; Maruhn, J A; Reinhard, P -G

2014-01-01

172

Applied Effective Field Theory to Nuclear Matter

An important issue when trying to apply effective field theory (EFT) methods to the nuclear matter problem is the identification of the expansion parameter. A perturbative matching calculation shows how the radius of convergence in free space is related to the radius of convergence in nuclear matter, and gives an estimate of the expansion parameter. Conventional approaches to nuclear matter find that the binding energy is sensitive to off-shell effects that depend on the two-body potential. (Coester et al., Phys. Rev. C 1), 769(1970)^, (M. I. Haftel and F. Tabakin, Phys. Rev. C 3), 921(1971) [4] In an EFT approach, observables should be independent of off-shell effects. The resolution of this discrepancy is discussed.

Tirfessa, Negussie; Furnstahl, R. J.

1999-10-01

173

Spin polarization phenomena in dense nuclear matter

Spin polarized states in nuclear matter with an effective nucleon-nucleon interaction are studied for a wide range of isospin asymmetries and densities. Based on a Fermi liquid theory, it is shown that there are a few possible scenarios of spin ordered phase transitions: (a) nuclear matter undergoes at some critical density a phase transition to a spin polarized state with the oppositely directed spins of neutrons and protons (Skyrme SLy4 and Gogny D1S interactions); (b) at some critical density, a spin polarized state with the like-directed neutron and proton spins appears (Skyrme SkI5 interaction); (c) nuclear matter under increasing density, at first, undergoes a phase transition to the state with the opposite directions of neutron and proton spins, which goes over at larger density to the state with the same direction of nucleon spins (Skyrme SkI3 interaction).

Isayev, A A

2007-01-01

174

Nuclear matter in strong magnetic fields

Strongly magnetized nuclear matter within the context of Quantum Hadrodynamics (Walecka-model) and its extensions is investigated in this article. The magnetic field is coupled to the charge and dipole moment of the baryons by including the appropriate terms in the Lagrangian density. The saturation density of magnetized, symmetric nuclear matter was calculated for magnetic fields of the order of 10^17 gauss. For the calculated range of saturation densities the binding energy, symmetry energy coefficient and compressibility of nuclear matter were also calculated. It is found that with an increasing magnetic field the saturation density also increases, while the system becomes less bound. Furthermore, the depopulation of proton Landau levels leaves a distinct oscillatory imprint on both the symmetry energy coefficient and the compressibility. The calculations were also performed for increased values of the baryon magnetic dipole moment. By increasing the dipole moment strength the saturation density is found t...

Diener, J P W

2013-01-01

175

Nuclear matter with three-body forces

International Nuclear Information System (INIS)

Full text: We present spectral calculations of nuclear matter properties, with three-body forces included in the in-medium T-matrix equations. The thermodynamic observables are computed for symmetric and pure neutron matter, and estimations for the density dependence of the symmetry energy are obtained. We also investigate the influence of three-body forces on the single-particle properties, discussing spectral functions, self-energies and effective masses. (author)

2009-01-18

176

Scale breaking in dense nuclear matter

International Nuclear Information System (INIS)

We extend the standard relativistic mean-field treatment of dense nuclear matter to make it consistent with the anomalous trace of the energy-momentum tensor of QCD. This is accomplished by introducing a field for scalar gluonium and coupling it to nucleons and to scalar and vector mesons. Only the gluonium potential, proportional to the bag constant, breaks scale invariance. A physically sensible, first-order, phase transition to quark matter occurs at high baryon density

1991-01-01

177

Resummations and chiral dynamics of nuclear matter

Energy Technology Data Exchange (ETDEWEB)

The equation of state of isospin-symmetric nuclear matter and pure neutron matter is calculated to three-loop order with in-medium chiral perturbation theory, taking into account also two-pion exchange with {Delta}-isobar excitations. The large empirical S-wave NN-scattering lengths, a{sub s}=19 fm and a{sub t}=-5.4 fm, require a non-perturbative treatment via a resummation of ladder diagrams to all orders. Our resummation method includes (combined) particle-particle and hole-hole rescatterings in the medium. The remaining short range part of the interaction is described by adjustable (p{sup 2}-dependent) NN-contact terms. In this framework the saturation properties of symmetric nuclear matter can be well reproduced and the nuclear matter compressibility takes on an improved value in comparison to earlier calculations without resummations. The neutron matter equation of state is particularly improved by the resummations. At low densities the energy per particle follows one half of the kinetic energy, which is a feature of the unitary Fermi gas. The results of sophisticated neutron matter calculations can be reproduced up to high neutron densities {rho}{sub n}=0.4 fm{sup 3}.

Schultess, Sebastian; Kaiser, Norbert; Weise, Wolfram [Physik-Department, Technische Universitaet Muenchen, Garching (Germany)

2012-07-01

178

Wanted! Nuclear Data for Dark Matter Astrophysics

Astronomical observations from small galaxies to the largest scales in the universe can be consistently explained by the simple idea of dark matter. The nature of dark matter is however still unknown. Empirically it cannot be any of the known particles, and many theories postulate it as a new elementary particle. Searches for dark matter particles are under way: production at high-energy accelerators, direct detection through dark matter-nucleus scattering, indirect detection through cosmic rays, gamma rays, or effects on stars. Particle dark matter searches rely on observing an excess of events above background, and a lot of controversies have arisen over the origin of observed excesses. With the new high-quality cosmic ray measurements from the AMS-02 experiment, the major uncertainty in modeling cosmic ray fluxes is in the nuclear physics cross sections for spallation and fragmentation of cosmic rays off interstellar hydrogen and helium. The understanding of direct detection backgrounds is limited by poor ...

Gondolo, Paolo

2013-01-01

179

Holographic cold nuclear matter and neutron star

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.

Ghoroku, Kazuo; Tachibana, Motoi; Toyoda, Fumihiko

2013-01-01

180

Holographic cold nuclear matter and neutron star

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//lineD8 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.

Ghoroku, Kazuo; Kubo, Kouki; Tachibana, Motoi; Toyoda, Fumihiko

2014-04-01

181

Nonlocal field theory model for nuclear matter

Energy Technology Data Exchange (ETDEWEB)

Nuclear matter is investigated in the relativistic Hartree approximation to a nonlocal A-E model containing short distance vertex form factors to simulate an underlying QCD substructure. At the Hartree level only the nucleon momentum dependence of the distributed vertex enters and the resulting finite nonlocal field theory model is solved in Euclidean metric with simple Gaussian forms for the so-called sideways form factors. To reproduce saturated nuclear matter the nonlocal model selects form-factor ranges at the nucleon mass scale.

Mishra, V.K.; Fai, G.; Tandy, Peter; Frank, Michael

1992-09-01

182

Nonlocal field theory model for nuclear matter

Energy Technology Data Exchange (ETDEWEB)

Nuclear matter is investigated in the relativistic Hartree approximation to a nonlocal {sigma}-{omega} model containing short distance vertex form factors to simulate an underlying QCD substructure. At the Hartree level only the nucleon momentum dependence of the distributed vertex enters and the resulting finite nonlocal field theory model is solved in Euclidean metric with simple Gaussian forms for the so-called sideways form factors. To reproduce saturated nuclear matter the nonlocal model selects form-factor ranges at the nucleon mass scale.

Mishra, V.K.; Fai, G.; Tandy, P.C. (Center for Nuclear Research, Department of Physics, Kent State University, Kent, Ohio 44242 (United States)); Frank, M.R. (Department of Physics, Hampton University, Hampton, Virginia 23668 (United States) Continuous Electron Beam Accelerator Facility, 12000 Jefferson Avenue, Newport News, Virginia 23606 (United States))

1992-09-01

183

Novel effects of electromagnetic interaction on the correlation of nuclear matter

The electromagnetic(EM) interactions between charged protons on the correlations of nuclear matter are discussed based on the meson-exchange picture of nuclear force. The Anderson-Higgs mechanism of broken U(1) EM symmetry is introduced in the frame of relativistic nuclear theory with a Debye/Meissner screening-like photon mass. The emphasis on the non-saturating Coulomb force contribution is on the equation of state (EOS) of nuclear matter and the breached $^1S_0$ paring correlations of $PP$ (proton-proton) and $NN$ (neutron-neutron). Due to the repulsive static electric interaction, the {\\em symmetric} nuclear matter at T=0 will become $asymmetric $ at $T\

Chen, J; Jin, M; Chen, Ji-sheng; Li, Jia-rong; Jin, Meng

2005-01-01

184

Femtotechnology: Nuclear Matter with Fantastic Properties

Directory of Open Access Journals (Sweden)

Full Text Available Problem statement: At present the term 'nanotechnology' is well known-in its' ideal form, the flawless and completely controlled design of conventional molecular matter from molecules or atoms. Such a power over nature would offer routine achievement of remarkable properties in conventional matter and creation of metamaterials where the structure not the composition brings forth new powers of matter. But even this yet unachieved goal is not the end of material science possibilities. The author herein offers the idea of design of new forms of nuclear matter from nucleons (neutrons, protons, electrons and other nuclear particles. Approach: The researcher researches the nuclear forces. He shows these force may be used for design the new nuclear matter from protons, neutrons, electrons and other nuclear particles. Results: Author shows this new 'AB-Matter' has extraordinary properties (for example, tensile strength, stiffness, hardness, critical temperature, superconductivity, supertransparency and zero friction., which are up to millions of times better than corresponding properties of conventional molecular matter. He shows concepts of design for aircraft, ships, transportation, thermonuclear reactors, constructions and so on from nuclear matter. These vehicles will have unbelievable possibilities (e.g., invisibility, ghost-like penetration through any walls and armor, protection from nuclear bomb explosions and any radiation flux. Conclusion: People may think this fantasy. But fifteen years ago most people and many scientists thought-nanotechnology is fantasy. Now many groups and industrial labs, even startups, spend hundreds of millions of dollars for development of nanotechnological-range products (precise chemistry, patterned atoms, catalysts and meta-materials and we have nanotubes (a new material which does not exist in Nature! and other achievements beginning to come out of the pipeline in prospect. Nanotubes are stronger than steel by a hundred times-surely an amazement to a 19th Century observer if he could behold them. Nanotechnology, in near term prospect, operates with objects (molecules and atoms having the size in nanometer (10-9 m. The researcher here outlines perhaps more distant operations with objects (nuclei having size in the femtometer range, (10-15m, millions of times less smaller than the nanometer scale. The name of this new technology is femtotechnology.

A. A. Bolonkin

2009-01-01

185

Probing Cold Dense Nuclear Matter

Energy Technology Data Exchange (ETDEWEB)

The nucleons in the nucleus can form strongly correlated pairs. Recent scattering experiments, in which a proton is knocked-out from carbon with high-momentum transfer and high missing momentum, have shown that neutron-proton pairs are nearly 20 times as prevalent as proton-proton and, by inference, neutron-neutron pairs. This result, which is due to tensor correlations, has implications for our understanding of nuclear systems from nuclei to neutron stars.

Higinbotham, Douglas

2008-10-01

186

Shock waves in relativistic nuclear matter, I

International Nuclear Information System (INIS)

The relativistic Rankine-Hugoniot relations are developed for a 3-dimensional plane shock and a 3-dimensional oblique shock. Using these discontinuity relations together with various equations of state for nuclear matter, the temperatures and the compressibilities attainable by shock compression for a wide range of laboratory kinetic energy of the projectile are calculated. 12 references

1979-01-01

187

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 "4"0Ar 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)

1986-01-01

188

Shock waves in relativistic nuclear matter. I

Energy Technology Data Exchange (ETDEWEB)

We develop the relativistic Rankine-Hugoniot relations for a three-dimensional plane shock and a three-dimensional oblique shock. Using these discontinuity relations together with various equations of state for nuclear matter, we calculate the temperatures and the compressibilities attainable by shock compression for a wide range of laboratory kinetic energy of the projectile.

Gleeson, A.M.; Raha, S.

1980-03-01

189

Probing Cold Dense Nuclear Matter

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.

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

190

Probing cold dense nuclear matter.

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. PMID:18511658

Subedi, R; Shneor, R; Monaghan, P; Anderson, B D; Aniol, K; Annand, J; Arrington, J; Benaoum, H; Benmokhtar, F; 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 J; 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; Sirca, S; Slifer, K; Solvignon, P; Sulkosky, V; Urciuoli, G M; Voutier, E; Watson, J W; Weinstein, L B; Wojtsekhowski, B; Wood, S; Zheng, X-C; Zhu, L

2008-06-13

191

Probing Cold Dense Nuclear Matter

Energy Technology Data Exchange (ETDEWEB)

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.

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

192

Nuclear matter to strange matter transition in holographic QCD

We construct a simple holographic QCD model to study nuclear matter to strange matter transition. The interaction of dense medium and hadrons is taken care of by imposing the force balancing condition for stable D4/D6/D6 configuration. By considering the intermediate and light flavor branes interacting with baryon vertex homogeneously distributed along R^3 space and requesting the energy minimization, we find that there is a well defined transition density as a function of current quark mass. We also find that as density goes up very high, intermediate (or heavy) and light quarks populate equally as expected from the Pauli principle. In this sense, the effect of the Pauli principle is realized as dynamics of D-branes.

Kim, Youngman; Sin, Sang-Jin

2009-01-01

193

Probing Nuclear Matter with Jet Conversions

We discuss the flavor of leading jet partons as a valuable probe of nuclear matter. We point out that the coupling of jets to nuclear matter naturally leads to an alteration of jet chemistry even at high transverse momentum $p_T$. In particular, QCD jets coupling to a chemically equilibrated quark gluon plasma in nuclear collisions, will lead to hadron ratios at high transverse momentum $p_T$ that can differ significantly from their counterparts in $p+p$ collisions. Flavor measurements could complement energy loss as a way to study interactions of hard QCD jets with nuclear matter. Roughly speaking they probe the inverse mean free path $1/\\lambda$, while energy loss probes the average momentum transfer $\\mu^2/\\lambda$. We present some estimates for the rate of jet conversions in a consistent Fokker-Planck framework and their impact on future high-$p_T$ identified hadron measurements at RHIC and LHC. We also suggest some novel observables to test flavor effects.

Liu, W

2008-01-01

194

The alpha-particle in nuclear matter

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 s...

Beyer, M.; Sofianos, S. A.; Kuhrts, C.; Roepke, G.; Schuck, P.

2000-01-01

195

Nucleon properties inside compressed nuclear matter

Our model calculations performed in the frame of the Bag Model (BM) approach show the modifications of nucleon mass, nucleon radius and a Parton Distribution Function (PDF) in Nuclear Matter (NM) above the saturation point. They originated from the pressure correction to the nucleon rest energy. Similar correction leads to conservation of a nuclear longitudinal momenta - essential in the explanation of the EMC effect at the saturation point of NM. Presented finite pressure corrections are generalization of the Hugenholtz-van Hove theorem valid for finite nucleon sizes inside NM.

Rozynek, Jacek

2014-01-01

196

A variational theory of nuclear matter. III

International Nuclear Information System (INIS)

Developments in a variational theory of nuclear matter for treating v6 homework potentials that include central, spin, isospin and tensor operators are reported. The central, spin, isospin and tensor correlations are parametrized by their range d, and the magnitudes of the non-central correlations. Integral equations are used to sum Fermi hypernetted chain, and single operator chain diagrams. All commutators required to evaluate the energy from the operator chain functions are treated exactly, and the energy is found to have a minimum with respect to variations in all parameters. Results of calculations with v6 models based on the Reid and Bethe-Johnson potentials are reported. A crude estimate of the effect of the spin-orbit potentials on nuclear matter binding energy indicates that it could be significant. (Auth.)

1979-04-02

197

Nuclear matter with scalar-vector interactions

Energy Technology Data Exchange (ETDEWEB)

The properties of cold nuclear matter are investigated in a class of nonlinear mean field [sigma]-[omega] theories which includes a density dependence of the meson parameters. This dependence can be both explicit and implicit through the effective nucleon mass. We apply the theory to the case of an interaction between the scalar and the vector mesons and investigate the properties of neutron stars using the resulting equation of state.

Moncada, A.; Scholtz, F.G.; Hahne, F.J.W. (Institute of Theoretical Physics, University of Stellenbosch, Stellenbosch 7600 (South Africa))

1994-09-01

198

Phase transition in warm nuclear matter

A density-dependent relativistic mean field (DRMF) theory is extended to that at finite temperature and density, and the liquid-gas phase transition of warm nuclear matter is investigated. Our results are compared with those obtained from the Walecka's mean field theory. The critical values of temperature, density, and pressure are calculated by the DRMF. The obtained critical temperature is Tc=12.66 MeV by using the parameter set A, which is in accord with recent experimental observation.

Hua, Guo; Bo, Liu; di Toro, M.

2000-09-01

199

Nuclear matter with scalar-vector interactions

International Nuclear Information System (INIS)

The properties of cold nuclear matter are investigated in a class of nonlinear mean field ?-? theories which includes a density dependence of the meson parameters. This dependence can be both explicit and implicit through the effective nucleon mass. We apply the theory to the case of an interaction between the scalar and the vector mesons and investigate the properties of neutron stars using the resulting equation of state

1994-09-01

200

Chiral density wave in nuclear matter

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 nu- clear 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 {\\rho}0, where {\\rho}0 is the nuclear matter ground-state density.

Heinz, Achim; Rischke, Dirk H

2013-01-01

201

Hot Nuclear Matter Equation of State with a Three-body Force

The finite temperature Brueckner-Hartree-Fock approach is extended by introducing a microscopic three-body force. In the framework of the extended model, the equation of state of hot asymmetric nuclear matter and its isospin dependence have been investigated. The critical temperature of liquid-gas phase transition for symmetric nuclear matter has been calculated and compared with other predictions. It turns out that the three-body force gives a repulsive contribution to the equation of state which is stronger at higher density and as a consequence reduces the critical temperature of liquid-gas phase transition. The calculated energy per nucleon of hot asymmetric nuclear matter is shown to satisfy a simple quadratic dependence on asymmetric parameter $\\beta$ as in the zero-temperature case. The symmetry energy and its density dependence have been obtained and discussed. Our results show that the three-body force affects strongly the high-density behavior of the symmetry energy and makes the symmetry energy mor...

Zuo, W; Li, A; Lu, G C

2004-01-01

202

Spin-isospin stability of nuclear matter

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 nuclear matter equation of state by adjusting an emerging contact-term) is spin-isospin stable, since $J(k_{f0})\\simeq 24 {\\rm MeV}>0$. The inclusion of the chiral $\\pi N\\Delta$-dynamics, necessary in order to guarantee the spin-stability of nuclear matter, keeps this property intact. The corresponding spin-isospin asymmetry energy $J(k_f)$ stays positive even for extreme values of an undetermined short-distance parameter $J_5$ (whose possible range we estimate from realistic NN-potentials). The largest positive contribution to $J(k_f)$ (a term ...

Kaiser, N

2005-01-01

203

Nuclear matter fourth-order symmetry energy in relativistic mean field models

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...

Cai, Bao-Jun

2011-01-01

204

Neutrinos, Dark Matter and Nuclear Detection

Energy Technology Data Exchange (ETDEWEB)

Solutions to problems in nuclear non-proliferation and counter-terrorism may be found at the forefront of modern physics. Neutrino oscillation experiments, dark matter searches, and high energy astrophysics, are based on technology advances that have may also have application to nuclear detection. The detection problems share many characteristics, including energy scales, time structures, particle-type, and, of course, the combination of high backgrounds and low signal levels. This convergence of basic and applied physics is realized in non-proliferation and homeland security projects at Lawrence Livermore National Laboratory. Examples described here include reactor anti-neutrino monitoring, dual-phase noble liquid TPC development, gamma-ray telescopes, and nuclear resonance fluorescence.

Goldstein, W H; Bernstein, A; Craig, W W; Johnson, M

2007-05-29

205

Three-body correlations in nuclear matter

International Nuclear Information System (INIS)

A momentum-space method is developed for the calculation of three-body terms in the Brueckner-Bethe method for nuclear matter. The method is similar to one used earlier for central S-wave potentials. Here we extend it to the full nuclear force, including tensor forces, spin-orbit forces, etc. Furthermore, we show how the method can be used to investigate the possibility of long-range correlations in nuclear matter by summing the generalized ring series. The numerical accuracy obtainable with various mesh parameters and cutoffs in momentum space, and with various truncations of partial-wave expansions, is thoroughly explored. Several angle-average approximations are used, and the estimated numerical accuracy in the three-body cluster energy is 10 --15 %. The method is applied to a central potential v_2, a semirealistic potential v_6(Reid), which has a tensor force, and to the Reid potential, augmented by an interaction that is consistent with empirical scattering phase shifts in two-body partial waves with j> or =3. In all cases the three-body contribution to the energy is correctly given in order of magnitude by kappa_2D_2, where D_2 is the two-body contribution and kappa_2 is the usual convergence parameter of the Brueckner-Bethe method. The generalized ring series is found to converge rapidly, indicating that long-range correlations are not very important for the binding energy of nuclear matter. The Reid potential is found to saturate at the right energy but at too high a density

1981-01-01

206

Consequences of DM/antiDM oscillations for asymmetric WIMP dark matter

Assuming the existence of a primordial asymmetry in the dark sector, a scenario usually dubbed Asymmetric Dark Matter (aDM), we study the effect of oscillations between dark matter and its antiparticle on the re-equilibration of the initial asymmetry before freeze-out, which enable efficient annihilations to recouple. We calculate the evolution of the DM relic abundance and show how oscillations re-open the parameter space of aDM models, in particular in the direction of allowing large (WIMP-scale) DM masses. A typical WIMP with a mass at the EW scale ( ~ 100 GeV - 1 TeV) presenting a primordial asymmetry of the same order as the baryon asymmetry naturally gets the correct relic abundance if the DM-number-violating ?(DM) = 2 mass term is in the ~ meV range. The re-establishment of annihilations implies that constraints from the accumulation of aDM in astrophysical bodies are evaded. On the other hand, the ordinary bounds from BBN, CMB and indirect detection signals on annihilating DM have to be considered.

Cirelli, Marco; Panci, Paolo; Servant, Géraldine; Zaharijas, Gabrijela

2012-03-01

207

The nuclear matter modification at intermediate energies

International Nuclear Information System (INIS)

A new hypothesis on hadron interactions with nuclear matter is discussed. It is supposed that the well-known particles and resonances as well as nucleons might serve as a target in the nucleus. The experimental data on CC, dC, CTa, pC interactions at 4.2 GeV/c/nucleon are used for the testing of the hypothesis. A certain suppression of production of the ?(1232) P_3_3, (1440) P_1_1 isobars and ? mesons is observed in these interactions, compared to the nucleon-nucleon interactions. It may be caused by the formation of the so-called dense 'resonance matter' in the nucleus. Special experiments with multiple rising statistics are required to examine the hypothesis

2002-01-01

208

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.)

1991-01-01

209

Electrostrong Nuclear Disintegration in Condensed Matter

Photo- and electro-disintegration techniques have been traditionally used for studying giant dipole resonances and through them nuclear structure. Over a long period, detailed theoretical models for the giant dipole resonances were proposed and low energy electron accelerators were constructed to perform experiments to test their veracity. More recently, through laser and "smart" material devices, electrons have been accelerated in condensed matter systems up to several tens of MeV. We discuss here the possibility of inducing electro-disintegration of nuclei through such devices. It involves a synthesis of electromagnetic and strong forces in condensed matter via giant dipole resonances to give an effective "electro-strong interaction" - a large coupling of electromagnetic and strong interactions in the tens of MeV range.

Swain, J; Widom, A

2013-01-01

210

Elementary diagrams in nuclear and neutron matter

International Nuclear Information System (INIS)

Variational calculations of nuclear and neutron matter are currently performed using a diagrammatic cluster expansion with the aid of nonlinear integral equations for evaluating expectation values. These are the Fermi hypernetted chain (FHNC) and single-operator chain (SOC) equations, which are a way of doing partial diagram summations to infinite order. A more complete summation can be made by adding elementary diagrams to the procedure. The simplest elementary diagrams appear at the four-body cluster level; there is one such E4 diagram in Bose systems, but 35 diagrams in Fermi systems, which gives a level of approximation called FHNC/4. We developed a novel technique for evaluating these diagrams, by computing and storing 6 three-point functions, Sxyz(r12, r13, r23), where xyz (= ccd, cce, ddd, dde, dee, or eee) denotes the exchange character at the vertices 1, 2, and 3. All 35 Fermi E4 diagrams can be constructed from these 6 functions and other two-point functions that are already calculated. The elementary diagrams are known to be important in some systems like liquid 3He. We expect them to be small in nuclear matter at normal density, but they might become significant at higher densities appropriate for neutron star calculations. This year we programmed the FHNC/4 contributions to the energy and tested them in a number of simple model cases, including liquid 3He and Bethe's homework problem. We get reasonable, but not exact agreement with earlier published work. In nuclear and neutron matter with the Argonne v14 interaction these contributions are indeed small corrections at normal density and grow to only 5-10 MeV/nucleon at 5 times normal density

1995-08-01

211

Neutrino Opacity in High Density Nuclear Matter

International Nuclear Information System (INIS)

We estimate the contribution of the nucleon weak magnetism on the neutrino absorption mean free path inside high density nuclear matter. In the mean field approach, three different ingredients are taken into account: (a) a relativistic generalization of the approach developed by Sanjay et al.; (b) the inclusion of the nucleon weak-magnetism (c) and the pseudo-scalar interaction involving the nucleons. Our main result shows that the neutrino absorption mean free path is three times the corresponding result obtained by those authors

2004-12-02

212

Effect of the $\\delta$-meson on the instabilities of nuclear matter under strong magnetic fields

We study the influence of the vectorial-scalar meson on the spinodal instabilities and the distillation effect in asymmetric non-homogeneous nuclear matter under strong magnetic fields, of the order of $ 10^{18}-10^{19}$ G. Relativistic nuclear models both with constant couplings (NLW) and with density dependent parameters (DDRH) are considered. A strong magnetic field can have large effects on the instability regions giving rise to bands of instability and wider unstable regions. It is shown that for neutron rich matter the inclusion of the $\\delta$ meson increases the size of the instability region for NLW models and decreases it for the DDRH models. The effect of the $\\delta$ meson on the transition density to homogeneous $\\beta$-equilibrium matter is discussed. The DDRH$\\delta$ model predicts the smallest transition pressures, about half the values obtained for NL$\\delta$.

Rabhi, A; Da Providencia, J

2009-01-01

213

Particle-hole states in nuclear matter

International Nuclear Information System (INIS)

This work deals with the collective excitations in nuclear matter, from the point of view of the TDA approximation. Our calculations involved the construction of a Hamiltonian, expressed as a matrix in the space of particle-hole excitations with a given momentum transfer. We used in this Hamiltonian an average single nucleon potential, and (in some cases) an effective interaction obtained for the potential HEA in the relativistic Brueckner-Hartree Fock theory. The eigenvectors of the TDA-Hamiltonian were used to compute the strength of the collective response of nuclear matter to external probes. Our results, succinctly described in the last section, are summarized in a set of figures at the end of this monograph. The specific form of the TDA equations that we used, and the procedure to calculate the degree of collectivity of the solutions, is studied in detail in the fifth chapter. A derivation of the TDA equations, and a discussion of the solutions for a separable potential, is given in the fourth chapter. The structure of a non-relativistic potential for a system of two nucleons is examined in the third chapter, in several representations. On the other hand, the particle-hole states relevant to our discussions on the TDA equations are introduced in the first two chapters

1985-01-01

214

A variational theory of nuclear matter

International Nuclear Information System (INIS)

The pair-correlation operator fsub(ij) in the variational wave function of nuclear matter is generated from a two-body Schroedinger equation with boundary conditions which require the correlated wave function to heal at a distance d. The two-body cluster energy is calculated exactly while the fsub(ij) is approximated by a sum of central, spin, isospin and tensor correlation operators to evaluate the many-body cluster contributions (MBCC). The distribution functions that represent the MBCC are expanded in powers of the non-central correlations. The zeroth order term in this expansion represents a sum of all MBCC with central correlations, and is evaluated by the Fermi hypernetted chain equations. The first order terms are identically zero, while all the second order terms are calculated. When the range of correlations d is about 2r0 the expansion appears to converge, and is used to obtain the upper bounds to the nuclear matter energy with various potentials. The upper bounds are much lower than energies suggested by earlier calculations; for example the Reid soft core potential gives E(ksub(F)=1.7 fm-1)0: however at such large values of d the three-body tensor rings in the second order terms give large negative contribution. General rules for calculating higher order terms in the expansion are given and the method seems simple enough to study the third and higher order terms. (Auth.)

1976-08-09

215

Incomprehensibility in finite nuclei and nuclear matter

The incompressibility (compression modulus) $K_{\\rm 0}$ of infinite symmetric nuclear matter at saturation density has become one of the major constraints on mean-field models of nuclear many-body systems as well as of models of high density matter in astrophysical objects and heavy-ion collisions. We present a comprehensive re-analysis of recent data on GMR energies in even-even $^{\\rm 112-124}$Sn and $^{\\rm 106,100-116}$Cd and earlier data on 58 $\\le$ A $\\le$ 208 nuclei. The incompressibility of finite nuclei $K_{\\rm A}$ is expressed as a leptodermous expansion with volume, surface, isospin and Coulomb coefficients $K_{\\rm vol}$, $K_{\\rm surf}$, $K_\\tau$ and $K_{\\rm coul}$. \\textit{Assuming} that the volume coefficient $K_{\\rm vol}$ is identified with $K_{\\rm 0}$, the $K_{\\rm coul}$ = -(5.2 $\\pm$ 0.7) MeV and the contribution from the curvature term K$_{\\rm curv}$A$^{\\rm -2/3}$ in the expansion is neglected, compelling evidence is found for $K_{\\rm 0}$ to be in the range 250 $ < K_{\\rm 0} < $ 315 MeV,...

Stone, J R; Moszkowski, S A

2014-01-01

216

Hadron-quark phase transition in asymmetric matter with dynamical quark masses

International Nuclear Information System (INIS)

The two-equation-of-state model is used to describe the hadron-quark phase transition in asymmetric matter formed at high density in heavy-ion collisions. For the quark phase, the three-flavor Nambu-Jona-Lasinio effective theory is used to investigate the influence of dynamical quark mass effects on the phase transition. At variance to the MIT-Bag results, with fixed-current quark masses, the main important effect of the chiral dynamics is the appearance of an end point for the coexistence zone. We show that a first-order hadron-quark phase transition may take place in the region T subset of (50-80) MeV and ?B subset of (2-4)?0, which is possible to be probed in the new planned facilities, such as FAIR at GSI-Darmstadt and NICA at JINR-Dubna. From the isospin properties of the mixed phase, some possible signals are suggested. The importance of chiral symmetry and dynamical quark mass on the hadron-quark phase transition is stressed. The difficulty of an exact location of a critical end point comes from its appearance in a region of competition between chiral symmetry breaking and confinement, where our knowledge of effective QCD theories is still rather uncertain.

2011-05-01

217

Hadron-quark phase transition in asymmetric matter with dynamical quark masses

The two-Equation of State (EoS) model is used to describe the hadron-quark phase transition in asymmetric matter formed at high density in heavy-ion collisions. For the quark phase, the three-flavor Nambu--Jona-Lasinio (NJL) effective theory is used to investigate the influence of dynamical quark mass effects on the phase transition. At variance to the MIT-Bag results, with fixed current quark masses, the main important effect of the chiral dynamics is the appearance of an End-Point for the coexistence zone. We show that a first order hadron-quark phase transition may take place in the region T=(50-80)MeV and \\rho_B=(2-4)\\rho_0, which is possible to be probed in the new planned facilities, such as FAIR at GSI-Darmstadt and NICA at JINR-Dubna. From isospin properties of the mixed phase somepossible signals are suggested. The importance of chiral symmetry and dynamical quark mass on the hadron-quark phase transition is stressed. The difficulty of an exact location of Critical-End-Point comes from its appearance...

Shao, G Y; Liu, B; Colonna, M; Greco, V; Liu, Y X; Plumari, S

2011-01-01

218

Hadron-quark phase transition in asymmetric matter with dynamical quark masses

The two-equation-of-state model is used to describe the hadron-quark phase transition in asymmetric matter formed at high density in heavy-ion collisions. For the quark phase, the three-flavor Nambu-Jona-Lasinio effective theory is used to investigate the influence of dynamical quark mass effects on the phase transition. At variance to the MIT-Bag results, with fixed-current quark masses, the main important effect of the chiral dynamics is the appearance of an end point for the coexistence zone. We show that a first-order hadron-quark phase transition may take place in the region T?(50-80)MeV and ?B?(2-4)?0, which is possible to be probed in the new planned facilities, such as FAIR at GSI-Darmstadt and NICA at JINR-Dubna. From the isospin properties of the mixed phase, some possible signals are suggested. The importance of chiral symmetry and dynamical quark mass on the hadron-quark phase transition is stressed. The difficulty of an exact location of a critical end point comes from its appearance in a region of competition between chiral symmetry breaking and confinement, where our knowledge of effective QCD theories is still rather uncertain.

Shao, G. Y.; di Toro, M.; Liu, B.; Colonna, M.; Greco, V.; Liu, Y. X.; Plumari, S.

2011-05-01

219

Self-interacting asymmetric dark matter coupled to a light massive dark photon

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 l...

Petraki, Kalliopi; Kusenko, Alexander

2014-01-01

220

Dark Matter Particle Spectroscopy at the LHC: Generalizing MT2 to Asymmetric Event Topologies

International Nuclear Information System (INIS)

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 MT2 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 MT2(max) of the MT2 distribution now gives the mass (tilde M)p((tilde M)c(a), (tilde M)c(b)) of the parent particles as a function of two input children masses (tilde M)c(a) and (tilde M)c(b). We propose two methods for an independent determination of the individual children masses Mc(a) and Mc(b). First, in the presence of upstream transverse momentum PUTM the corresponding function (tilde M)p((tilde M)c(a), (tilde M)c(b), PUTM) is independent of PUTM 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)c(a), (tilde M)c(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.

2010-04-01

221

Nuclear dynamics of mass asymmetric systems at balance energy

International Nuclear Information System (INIS)

In the search of nuclear equation of state as well as of nuclear interactions and forces, collective transverse flow has been found to be of immense importance. At low incident energies, the collective transverse flow is dominated by attractive interactions and the flow is expected to be negative, while at high incident energies, the flow is dominated by nucleon-nucleon repulsive interactions and is expected to be positive. While going from low to high incident energies, collective transverse flow vanishes at a particular value of energy, which is termed as Balance Energy (Ebal). The Ebal has been reported to be of significance toward the understanding of nuclear interactions and related dynamics

2011-12-01

222

Nuclear dynamics of mass asymmetric systems at balance energy

International Nuclear Information System (INIS)

In search of nuclear equation of state as well as of nuclear interactions and forces, collective transverse flow has been found to be of immense importance. At low incident energies, the collective transverse flow is dominated by attractive interactions and the flow is expected to be negative, while at high incident energies, the flow is dominated by nucleon-nucleon repulsive interactions and is expected to be positive. A complete systematic analysis of the nuclear dynamics at the Ebal for nearly symmetric reactions is reported in the literature, but no attempt has been made to see the effect of mass asymmetry on the nuclear dynamics at balance energy. The aim is to address this question in the present study using Quantum Molecular Dynamics (QMD) model

2013-12-01

223

Relativistic calculation of polarized nuclear matter

International Nuclear Information System (INIS)

The binding energy of nuclear matter with excess of neutrons, of spin-up neutrons, and spin-up protons (characterized by the corresponding parameters, ?sub(tau) = (N - Z)/A, ?sub(N) = (N - N )/A, and ?sub(p) = (Z - Z)/A)), contains three symmetry energies: the isospin symmetry energy epsilon sub(?), the spin symmetry energy epsilon sub(?), and the spin-isospin symmetry energy epsilon sub(?tau). The relativistic corrections to epsilon sub(tau), epsilon sub(?) and epsilon sub(?tau) are found to be -2.06, -2.6 and -0.89 MeV respectively. The relativistic correction to the compression modulus is -10.8 MeV. (author)

1979-01-01

224

Symmetry Energy of Dilute Warm Nuclear Matter

International Nuclear Information System (INIS)

The symmetry energy of nuclear matter is a fundamental ingredient in the investigation of exotic nuclei, heavy-ion collisions, and astrophysical phenomena. New data from heavy-ion collisions can be used to extract the free symmetry energy and the internal symmetry energy at subsaturation densities and temperatures below 10 MeV. Conventional theoretical calculations of the symmetry energy based on mean-field approaches fail to give the correct low-temperature, low-density limit that is governed by correlations, in particular, by the appearance of bound states. A recently developed quantum-statistical approach that takes the formation of clusters into account predicts symmetry energies that are in very good agreement with the experimental data. A consistent description of the symmetry energy is given that joins the correct low-density limit with quasiparticle approaches valid near the saturation density.

2010-05-21

225

Attenuation of ? mesons in cold nuclear matter

International Nuclear Information System (INIS)

The attenuation of ? mesons in cold nuclear matter has been investigated via the time-dependent multiple-scattering Monte Carlo multicollisional (MCMC) intranuclear cascade model. The inelastic ? width deduced from CBELSA/TAPS Collaboration data of meson transparency in complex nuclei (?*?30 MeV/c2) is approximately 5 times lower than the value obtained with recent theoretical models and consistent with an in-medium total ?N cross section within 25-30 mb for an average meson momentum of 1.1 GeV/c . The momentum-dependent transparency ratios suggest an elastic/total cross-section ratio around 40%. For the case of CLAS Collaboration data a much higher width is deduced (?* > or approx. 120 MeV/c2), with the MCMC model providing a consistent interpretation of the data, assuming a much higher meson absorption (??N* > or approx. 100 mb) for p??1.7 GeV/c.

2011-08-01

226

Bulk Properties of Symmetric Nuclear and Pure Neutron Matter

Directory of Open Access Journals (Sweden)

Full Text Available We study the equation of state (EOS of symmetric nuclear and neutron matter within the framework of the Brueckner-Hartree-Fock (BHF approach which is extended by including a density-dependent contact interaction to achieve the empirical saturation property of symmetric nuclear matter. This method is shown to affect significantly the nuclear matter EOS and the density dependence of nuclear symmetry energy at high densities above the normal nuclear matter density, and it is necessary for reproducing the empirical saturation property of symmetric nuclear matter in a nonrelativistic microscopic framework. Realistic nucleon-nucleon interactions which reproduce the nucleon-nucleon phase shifts are used in the present calculations.

Khaled Hassaneen

2013-05-01

227

Strangeness and charm in nuclear matter

International Nuclear Information System (INIS)

The properties of strange (K, K¯ and K¯?) and open-charm (D, 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, K¯ and 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 ?A?K+K??A? reaction, which we propose as a tool to detect in-medium modifications of the K¯? meson. On the other hand, in the charm sector, several resonances with negative parity are generated dynamically by the s-wave interaction between pseudoscalar and vector meson multiplets with 1/2+ and 3/2+ baryons. The properties of these states in matter are analyzed and their influence on the open-charm meson spectral functions is studied. We finally discuss the possible formation of D-mesic nuclei at FAIR energies

2013-09-20

228

Cold Nuclear Matter Effects at PHENIX

Energy Technology Data Exchange (ETDEWEB)

While the study of the quark-gluon plasma has been the primary focus of the RHIC experiments, much work has also been done to understand so-called cold nuclear matter (CNM) eects through d+Au collisions where no hot plasma is produced. Eects such as nuclear shadowing, Cronin enhancement, and initial-state parton energy loss, among others, are not only interesting in their own right, but have direct implications on QGP-related measurements in A+A collisions. Recently PHENIX has measured CNM eects at midrapidity in s_NN = 200 GeV d+Au collisions. Measurements of reconstructed jets reveal the centrality dependence of both jet suppression and broadening of the away-side jet. Meanwhile, single electrons from heavy flavor decays exhibit enhancement, increasing with centrality, over a broad p_T range. J/psi and psi' modification have also been measured and are quite dierent in magnitude, in contrast with our expectations. The above results are presented here and compared to our present understanding of CNM effects.

Wysocki, Matthew G [ORNL; PHENIX, Collaboration [The

2013-01-01

229

Cold Nuclear Matter Effects at PHENIX

While the study of the quark-gluon plasma has been the primary focus of the RHIC experiments, much work has also been done to understand so-called cold nuclear matter (CNM) effects through d + Au collisions where no hot plasma is produced. Effects such as nuclear shadowing, Cronin enhancement, and initial-state parton energy loss, among others, are not only interesting in their own right, but have direct implications on QGP-related measurements in A + A collisions.Recently PHENIX has measured CNM effects at midrapidity in sNN=200 GeVd + Au collisions. Measurements of reconstructed jets reveal the centrality dependence of both jet suppression and broadening of the away-side jet. Meanwhile, single electrons from heavy flavor decays exhibit enhancement, increasing with centrality, over a broad pT range. J/? and ?? modification have also been measured and are quite different in magnitude, in contrast with our expectations. The above results are presented here and compared to our present understanding of CNM effects.

Wysocki, Matthew G.

2013-05-01

230

Phase transitions in nuclear matter and consequences for neutron stars

International Nuclear Information System (INIS)

Estimates of the minimal bombarding energy necessary to reach the quark gluon phase in heavy ion collisions are presented within a hydrodynamical scenario. Further, the consequences of first-order phase transitions from nuclear/neutron matter to pion-condensed matter or quark matter are discussed for neutron stars. (author)

1983-01-01

231

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)

1979-01-01

232

On the thermal properties of polarised nuclear matter

International Nuclear Information System (INIS)

The thermal properties of polarised nuclear matter are calculated using the Skyrme-III interaction as modified by Dabrowski (Nukleonika;21:143 (1977)) for polarised nuclear matter. The temperature dependences of the volume, isospin, spin and spin-isospin pressure and energies are determined. The temperature, isospin, spin and spin-isospin dependences of the equilibrium Fermi momentum are also discussed. (author)

1980-01-01

233

Simulation study for the nuclear matter below the saturation density

International Nuclear Information System (INIS)

The infinite nuclear matter that consists of numerous protons and neutrons is described by using periodic boundary conditions. The motion of each nucleon in the fundamental cell is decided by a Molecular Dynamics. The ground states or the excited states of the nuclear matter are simulated. (author)

1999-08-01

234

Sigma model calculations of neutron-rich nuclear matter

International Nuclear Information System (INIS)

We examine the role of many-body effects provided by the chiral sigma model in the equation of state of symmetric nuclear matter and neutron-rich matter. Using the parameters determined by fitting the known equilibrium properties of symmetric and slightly neutron-rich matter, the equation of state with arbitrary neutron excess is calculated. The role of the nuclear symmetry energy on the structure of beta stable neutron stars is discussed

1987-01-01

235

Probing isospin- and momentum-dependent nuclear effective interactions in neutron-rich matter

Energy Technology Data Exchange (ETDEWEB)

The single-particle potential for nucleons and hyperons in neutron-rich matter generally depends on the density and isospin asymmetry of the medium as well as the momentum and isospin of the particle. It further depends on the temperature of the matter if the latter is in thermal equilibrium. We review here the extension of a Gogny-type isospin- and momentum-dependent interactions in several aspects made in recent years and their applications in studying intermediate-energy heavy-ion collisions, thermal properties of asymmetric nuclear matter and properties of neutron stars. The importance of the isospin and momentum dependence of the single-particle potential, especially the momentum dependence of the isovector potential, is clearly revealed throughout these studies. (orig.)

Chen, Lie-Wen [Shanghai Jiao Tong University, Department of Physics and Astronomy and Shanghai Key Laboratory for Particle Physics and Cosmology, Shanghai (China); National Laboratory of Heavy Ion Accelerator, Center of Theoretical Nuclear Physics, Lanzhou (China); Ko, Che Ming [Texas A and M University, Cyclotron Institute and Department of Physics and Astronomy, College Station, TX (United States); Li, Bao-An [Texas A and M University-Commerce, Department of Physics and Astronomy, Commerce, TX (United States); Xi' an Jiao Tong University, Department of Applied Physics, Xi' an (China); Xu, Chang [Nanjing University, Department of Physics, Nanjing (China); Xu, Jun [Chinese Academy of Sciences, Shanghai Institute of Applied Physics, Shanghai (China)

2014-02-15

236

Strangeness and charm in nuclear matter

Energy Technology Data Exchange (ETDEWEB)

The properties of strange (K, K{sup ¯} and K{sup ¯?}) and open-charm (D, D{sup ¯} and D{sup ?}) 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, K{sup ¯} and K{sup ¯?} 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 ?A?K{sup +}K{sup ??}A{sup ?} reaction, which we propose as a tool to detect in-medium modifications of the K{sup ¯?} meson. On the other hand, in the charm sector, several resonances with negative parity are generated dynamically by the s-wave interaction between pseudoscalar and vector meson multiplets with 1/2{sup +} and 3/2{sup +} baryons. The properties of these states in matter are analyzed and their influence on the open-charm meson spectral functions is studied. We finally discuss the possible formation of D-mesic nuclei at FAIR energies.

Tolos, Laura, E-mail: tolos@ice.csic.es [Instituto de Ciencias del Espacio (IEEC/CSIC), Campus Universitat Autònoma de Barcelona, Facultat de Ciències, Torre C5, E-08193 Bellaterra (Barcelona) (Spain); Frankfurt Institute for Advanced Studies, Johann Wolfgang Goethe University, Ruth-Moufang-Str. 1, 60438 Frankfurt am Main (Germany); Cabrera, Daniel [Departamento de Física Teórica II, Universidad Complutense, 28040 Madrid (Spain); Garcia-Recio, Carmen [Departamento de Física Atómica, Molecular y Nuclear, and Instituto Carlos I de Física Teórica y Computacional, Universidad de Granada, E-18071 Granada (Spain); Molina, Raquel [Research Center for Nuclear Physics (RCNP), Mihogaoka 10-1, Ibaraki 567-0047 (Japan); Nieves, Juan; Oset, Eulogio [Instituto de Física Corpuscular (Centro Mixto CSIC-UV), Institutos de Investigación de Paterna, Aptdo. 22085, 46071 Valencia (Spain); Ramos, Angels [Departament d' Estructura i Constituents de la Matèria, Universitat de Barcelona, Diagonal 647, 08028 Barcelona (Spain); Romanets, Olena [Theory Group, KVI, University of Groningen, Zernikelaan 25, 9747 AA Groningen (Netherlands); Salcedo, Lorenzo Luis [Departamento de Física Atómica, Molecular y Nuclear, and Instituto Carlos I de Física Teórica y Computacional, Universidad de Granada, E-18071 Granada (Spain)

2013-09-20

237

A fermionic molecular dynamics technique to model nuclear matter

International Nuclear Information System (INIS)

Full text: At sub-nuclear densities of about 1014 g/cm3, nuclear matter arranges itself in a variety of complex shapes. This can be the case in the crust of neutron stars and in core-collapse supernovae. These slab like and rod like structures, designated as nuclear pasta, have been modelled with classical molecular dynamics techniques. We present a technique, based on fermionic molecular dynamics, to model nuclear matter at sub-nuclear densities in a semi classical framework. The dynamical evolution of an antisymmetric ground state is described making the assumption of periodic boundary conditions. Adding the concepts of antisymmetry, spin and probability distributions to classical molecular dynamics, brings the dynamical description of nuclear matter to a quantum mechanical level. Applications of this model vary from investigation of macroscopic observables and the equation of state to the study of fundamental interactions on the microscopic structure of the matter. (author)

2009-01-18

238

Kaon Condensation and the Non-Uniform Nuclear Matter

Non-uniform structures of nuclear matter are studied in a wide density-range. Using the density functional theory with a relativistic mean-field model, we examine non-uniform structures at sub-nuclear densities (nuclear ``pastas'') and at high densities, where kaon condensate is expected. We try to give a unified view about the change of the matter structure as density increases, carefully taking into account the Coulomb screening effects from the viewpoint of first-order phase transition.

Maruyama, T; Voskresensky, D N; Tanigawa, T; Chiba, S; Maruyama, Toshiki; Tatsumi, Toshitaka; Voskresensky, Dmitri N.; Tanigawa, Tomonori; Chiba, Satoshi; Maruyama, Toshiki; Tatsumi, Toshitaka; Voskresensky, Dmitri N.; Tanigawa, Tomonori; Chiba, Satoshi

2003-01-01

239

Kaon Condensation and the Non-Uniform Nuclear Matter

Digital Repository Infrastructure Vision for European Research (DRIVER)

Non-uniform structures of nuclear matter are studied in a wide density-range. Using the density functional theory with a relativistic mean-field model, we examine non-uniform structures at sub-nuclear densities (nuclear ``pastas'') and at high densities, where kaon condensate is expected. We try to give a unified view about the change of the matter structure as density increases, carefully taking into account the Coulomb screening effects from the viewpoint of first-order ph...

Maruyama, Toshiki; Tatsumi, Toshitaka; Voskresensky, Dmitri N.; Tanigawa, Tomonori; Chiba, Satoshi

2003-01-01

240

The curvature dependence of the surface tension of nuclear matter

International Nuclear Information System (INIS)

It is shown that the curvature dependence of the surface tension of nuclear matter is analogous to that of normal liquids. This can be described quantitatively by the modified Tolman equation. The surface tension of plane nuclear matter is 2.4 x 1017 Nm-1. According to its physical meaning the delta-parameter has been interpreted as the half-width of the nuclear surface. (author)

1981-01-01

241

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.)

2007-01-01

242

Antikaons in infinite nuclear matter and nuclei

Energy Technology Data Exchange (ETDEWEB)

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.)

Moeller, M.

2007-12-10

243

International Nuclear Information System (INIS)

Properties of nuclear matter and neutron stars and their density-dependent correlations are discussed in a nonlinear ?-?-? mean-field approximation with self-interactions and mixed-interactions of mesons. The nonlinear interactions are renormalized as effective masses (MN*, m?*, m?*, m?*) and effective coupling constants (g?*, g?*, g?*) required by the theory of conserving approximations, which generates a thermodynamically consistent approximation essential to examine density-dependent correlations. The nonlinear ?-?-? mean-field approximation becomes equivalent to Hartree approximation with effective masses and effective coupling constants, and self-consistent structure is clarified. The current nonlinear mean-field approximation is applied to neutron-rich nuclear matter which is defined as isospin asymmetric and beta-equilibrium nuclear matter. The density-dependent correlations between properties of isospin symmetric and asymmetric nuclear matter, the saturation of symmetry energy in high densities are discussed in terms of density-dependent, effective masses and effective coupling constants induced by nonlinear interactions. The accumulating data and accurate measurements of effective masses and effective coupling constants, observables in high energy density will supply significant information in order to understand and testify theoretical consistency of nuclear models

2008-02-01

244

Exploring compressed nuclear matter with HADES

Energy Technology Data Exchange (ETDEWEB)

In the energy domain of E{sub kin}=1-2 GeV per nucleon, HADES has measured rare and penetrating probes in C+C, Ar+KCl, p+p, d+p and p+Nb collisions. Our results demonstrate that electron pair emission in C+C collisions can essentially be explained as a superposition of independent N+N collisions. A comparison of the N+N reference spectrum with the e{sup +}e{sup -} invariant-mass distribution measured in Ar+KCl collisions, however, shows a pronounced excess radiation, which can be attributed to emission from the dense phase of the collision zone. Moreover, for the first time at SIS energies, a clear {omega} signal was observed. Also in p+p interactions at 3.5 GeV the inclusive production cross sections for {pi}{sup 0}, {eta}, {rho} and {omega} mesons are extracted for the first time. This result allows putting tight constraints on vector meson production in heavy-ion and elementary collisions at beam energies of a few GeV. Intriguing results where also obtained from the reconstruction of hadrons with open and hidden strangeness. While the measured hadron yields are well described assuming thermalization, the reconstructed double-strange baryon {Xi}{sup -} appears about ten times more abundant than expected. This result is discussed in the context of the exploration of the nuclear matter phase diagram in the region of finite density.

Galatyuk, Tatyana [Goethe-Universitaet, Frankfurt am Main (Germany); ExtreMe Matter Institute EMMI, Darmstadt (Germany); Collaboration: HADES-Collaboration

2011-07-01

245

Kaons in nuclear matter; Kaonen in Kernmaterie

Energy Technology Data Exchange (ETDEWEB)

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.

Kolomeitsev, E.E.

1997-02-01

246

Strangeness and Charm in Nuclear Matter

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....

Tolos, Laura; Garcia-Recio, Carmen; Molina, Raquel; Nieves, Juan; Oset, Eulogio; Ramos, Angels; Romanets, Olena; Salcedo, Lorenzo Luis

2012-01-01

247

The inclusive transverse response of nuclear matter

The electromagnetic inclusive transverse response of nuclear matter at saturation density is studied within the correlated basis function perturbation theory for momentum transfers q from 300 to 550 MeV/c. The correlation operator includes a Jastrow component, accounting for the short range repulsion, as well as longer range spin, tensor and isospin ones. The Schiavilla- Pandharipande-Riska model for the two-body electromagnetic currents, satisfying the continuity equation with realistic v_14 potentials, is adopted. Currents due to intermediate Delta-isobar excitations, are also included. The global contribution of the two-body currents turns out to be positive and provides an enhancement of the one-body transverse response ranging from about 20% for the lower momenta to about 10% for the higher ones. This finding is in agreement with the Green's Function Monte Carlo studies of the transverse Euclidean response in A=3,4 nuclei and contradicts previous results obtained within the Fermi gas and shell models. Th...

Fabrocini, A

1997-01-01

248

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.)

2011-01-01

249

Nuclear matter and neutron stars in a parity doublet model

International Nuclear Information System (INIS)

We investigate the properties of isospin-symmetric nuclear matter and neutron stars in a chiral model approach adopting the SU(2) parity-doublet formulation. This ansatz explicitly incorporates chiral symmetry restoration with the limit of degenerate masses of the nucleons and their parity partners. Instead of searching for an optimized parameter set we explore the general parameter dependence of nuclear matter and star properties in the model. We are able to get a good description of ground-state nuclear matter as well as large values of mass for neutron stars in agreement with observation

2008-02-01

250

Properties of the ?-meson in dense nuclear matter

International Nuclear Information System (INIS)

The properties of ?-mesons in dense nuclear matter are studied in a model which satisfies unitarity and current conservation. The important coupling of the ?-meson to two pions as well as the strong mixing of pions and delta-nucleon-hole states in nuclear matter are included. The ?-meson self energy in nuclear matter is evaluated with in-medium pion propagators and the corresponding vertex corrections required by current conservation. We find that the ?-meson width grows drastically with increasing density while its mass remains almost unchanged. (orig.)

1992-01-01

251

Effect of charge dependence of nuclear force on the properties of nuclear matter

International Nuclear Information System (INIS)

In this paper, the effect of charge dependence of nuclear force on the properties of nuclear matter has been investigated. Our results show that at low densities, the difference between charge dependent and charge independent cases in the nuclear matter calculations is ignorable but, at high densities, this effect is considerable

2005-02-23

252

Influence of mesonic and nuclear selfenergies on the binding energy of nuclear matter

Energy Technology Data Exchange (ETDEWEB)

- and rho-meson selfenergies are applied in nuclear matter calculations. It is shown that they lead to an additional attraction of nearly 10 MeV at nuclear matter density. However, this effect is almost exactly cancelled by nuclear selfenergy corrections. (orig.).

Machleidt, R.; Holinde, K.

1985-03-14

253

Energy Technology Data Exchange (ETDEWEB)

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.)

Typel, S.; Wolter, H.H. [Sektion Physik, Univ. Muenchen, Garching (Germany)

1998-06-01

254

Deuteron-, triton - and alpha - clusters in nuclear matter

International Nuclear Information System (INIS)

It is studied with a simple model how deuteron-, triton- and ?-clusters behave concerning their cluster structure identities during the scatterring process and just after reaching nuclear matter of finite size. (Author)

1981-01-01

255

The Nucleon Mass and the EOS of Nuclear Matter

International Nuclear Information System (INIS)

We show in the simple model independent of photon momentum transfer the density evolution for the parton distribution in nuclear matter. The correction to the Fermi energy from term proportional to the pressure are very important. (author)

2008-02-01

256

Many-body theory of nuclear and neutron star matter

Energy Technology Data Exchange (ETDEWEB)

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.)

Pandharipande, V.R.; Akmal, A.; Ravenhall, D.G. [Dept. of Physics, Univ. of Illinois at Urbana-Champaign, Urbana, IL (United States)

1998-06-01

257

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.)

1998-01-11

258

Nuclear matter equation of state and three-body forces

Energy Technology Data Exchange (ETDEWEB)

The energy per particle, symmetry energy, pressure, and free energy are calculated for symmetric nuclear matter using BHF approach with modern nucleon-nucleon CD-Bonn, Nijm1, Argonne v{sub 18}, and Reid 93 potentials. To obtain saturation in nuclear matter we add three-body interaction terms which are equivalent to a density-dependent two-nucleon interaction a la Skyrme force. Good agreement is obtained in comparison with previous theoretical estimates and experimental data.

Mansour, H. M. M.; Algamoudi, A. M. A. [Cairo University, Physics Department, Faculty of Science (Egypt)

2012-04-15

259

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)

1986-01-01

260

Hot Nuclear Matter in the Quark Meson Coupling Model

Digital Repository Infrastructure Vision for European Research (DRIVER)

We study here hot nuclear matter in the quark meson coupling (QMC) model which incorporates explicitly quark degrees of freedom, with quarks coupled to scalar and vector mesons. The equation of state of nuclear matter including the composite nature of the nucleons is calculated at finite temperatures. The calculations are done taking into account the medium-dependent bag constant. Nucleon properties at finite temperatures as calculated here are found to be appreciably differ...

Panda, P. K.; Mishra, A.; Eisenberg, J. M.; Greiner, W.

1997-01-01

261

Electron-positron pair production in high temperature nuclear matter

Energy Technology Data Exchange (ETDEWEB)

The general features of electron-positron emission from high temperature nuclear matter are discussed. Estimates are made of the production rates arising from incoherent nucleon-nucleon scattering and from two pion annihilation. It may be possible to infer the pion dispersion relation in hot and dense nuclear matter by measuring the invariant mass distribution of back-to-back electrons and positrons in the center of mass frame in high energy nucleus-nucleus collisions.

Gale, C.; Kapusta, J.

1987-09-07

262

Longitudinal spin-dependent correlations in nuclear matter

International Nuclear Information System (INIS)

A Jastrow-type wave function, with the two-body correlation factor depending on the spin-isospin state of the particles, is used for variational calculations of the energy per particle of infinite Fermi systems. Results are presented for nuclear matter and neutron matter using two semi-realistic potentials. (orig.)

1981-04-23

263

a Fuzzy Bag Model for Nuclear Matter:. a Preliminary Approach

In this work we develop an effective formalism for nuclear matter based on the fuzzy bag model. The main objective of our study is to discuss the feasibility of using the fuzzy bag model to describe nuclear matter properties. The physical system is described in our approach by an internal energy function, which has a free term, corresponding to a free Fermi gas, and an interacting one. In the interacting part, pion exchange is taken into account via an effective potential. To avoid superposition of nucleons, we introduce an exclusion volume à la Van der Waals. The internal energy function depends on the nuclear matter density and also on a parameter which will determine the expected volume of a nucleon in matter. We then obtain results for the binding energy per nucleon for the symmetric nuclear matter and for neutron matter, as well as the equation of state within this model. We then determine the mass of neutron stars in hydrostatic equilibrium, using the TOV equations. In spite of utilizing a treatment that is still very preliminary, our results show the feasibility of using this treatment to describe nuclear matter properties.

Rocha, A. S. S.; Vasconcellos, C. A. Z.; Fernández, F.

264

Nuclear incompressibility: from finite nuclei to nuclear matter

International Nuclear Information System (INIS)

The recent increase of experimental data concerning the Giant Monopole Resonance Energy Esub(M) gives information on the incompressibility modulus of nuclear matter, provided one can extrapolate the incompressibility of a nucleus Ksub(A) defined by Esub(M)=[h2/m KA/2>]sup(1/2), to the infinite medium. We discuss the theoretical interpretation of the coefficients of an Asup(-1/3) - expansion of Ksub(A) by studying the asymptotic behaviour of two RPA sum rules (corresponding to the scaling and the constrained model), evaluated using self-consistent Thomas-Fermi calculations. We show that the scaling model is the most suitable one as it leads to a rapidly converging Asup(-1/3)-expansion of the corresponding incompressibility Ksub(A)sup(S), whereas this is not the case with the constrained model. Some semi-empirical relations between the coefficients of the expansion of Ksub(A)sup(S) are established, which reduce to one the number of free-parameters in a best fit analysis of the experimental data. This reduction is essential due to the still limited number and accuracy of experimental data. We then show the compatibility of the data given by the various experimental groups with this parametrization and obtain a value of Ksub(nm)=220+-20 MeV, in good agreement with more microscopic analysis

1981-01-01

265

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)

1988-01-01

266

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)

1998-01-01

267

Energy Technology Data Exchange (ETDEWEB)

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)

Ducoin, C

2006-10-15

268

Nuclear Matter Properties of the Modified Quark Meson Coupling Model

We explore in more detail the modified quark meson coupling (MQMC) model in nuclear matter. Based on previous studies two different functional forms for the density dependence of the bag constant are discussed. For uniform matter distributions the MQMC model can be cast in a form identical to QHD by a redefinition of the sigma meson field. It is then clear that modifications similar to those introduced in QHD will permit the reproduction of all nuclear matter properties including the compressibility. After calibrating the model parameters at equilibrium nuclear matter density, the model and parameter dependence of the resulting equation of state is examined. Nucleon properties and scaling relations between the bag constant and the effective nucleon mass are discussed.

Müller, H; Mueller, Horst; Jennings, Byron K.

1997-01-01

269

Phase equilibrium of pion condensed and normal anisotropic nuclear matter

International Nuclear Information System (INIS)

The equation of state and anisotropy of inifinite nuclear matter are investigated at finite temperature in the frame of Walecka model using mean-field approximation. At fixed temperature and free enthalpy the pion condensed nuclear matter is isotropic in equilibrium state. At fixed temperature and mean pressure the anisotropy of pion condensed matter is of the same kind as one of the anisotropic normal nuclear matter produced in heavy ion collisions. The equilibrium of pion-condensed and non-equilibrium anisotropic normal phases may occur at realistic values of anisotropy, i.e. the anisotropy cannot impede the phase transition in the frame of the model presented. This phase transition is accompanied with production of latent heat. (D.Gy.)

1984-01-01

270

Relativistic Mean-Field Hadronic Models under Nuclear Matter Constraints

Relativistic mean-field (RMF) models have been widely used in the study of many hadronic frameworks 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. With the aim of identifying the models which best satisfy well known properties of nuclear matter, we have analyzed 263 parameterizations of seven different types of RMF models under three different sets of constraints related to symmetric nuclear matter, pure neutron matter, symmetry energy, and its derivatives. One of these (SET1) is formed of the same constraints used in a recent work in which we analyzed 240 Skyrme parameterizations. The results pointed to 2 models consistent with all constraints. Using another set of constraints, namely, SET2a, formed by the updated versions of the previous one, we found 4 models approved simultan...

Dutra, M; Avancini, S S; Carlson, B V; Delfino, A; Menezes, D P; Providência, C; Typel, S; Stone, J R

2014-01-01

271

Nuclear dynamics at the balance energy of mass asymmetric colliding nuclei

Digital Repository Infrastructure Vision for European Research (DRIVER)

Using the quantum molecular dynamics model, we study the nuclear dynamics at the balance energy of mass asymmetric colliding nuclei by keeping the total mass of the system fixed as 40, 80, 160, and 240. The calculations are performed by varying the mass asymmetry ($\\eta$ = $\\frac{A_{T}-A_{P}}{A_{T}+A_{P}}$; where $A_{T}$ and $A_{P}$ are the masses of the target and projectile, respectively) of the reaction from 0.1 to 0.7. In particular, we study the various quantities like ...

Goyal, Supriya

2011-01-01

272

Study of participant-spectator matter and thermalization in isospin asymmetric systems

We study the behavior of participant and spectator matter and thermalization in neutron rich systems at the energy of vanishing flow. Our study indicates that participant-spectator matter follows a similar behavior for neutron-rich systems and for systems lie on the stability line.

Gautam, Sakshi

2011-01-01

273

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.)

1993-01-01

274

Asymmetric Sneutrino Dark Matter and the $\\Omega_{\\rm{b}}/\\Omega_{\\rm{DM}}$ Puzzle

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 {\\it a priori} 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 $\\Omega_{\\rm{b}}$ and $\\Omega_{\\rm{dm}}$. 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.

Hooper, D; West, S M; Hooper, Dan; March-Russell, John; West, Stephen M.

2004-01-01

275

Nuclear matter saturation density: From finite nuclei to infinite matter

International Nuclear Information System (INIS)

The accuracy of Hartree-Fock (HF) calculations of the average density anti ? in the core of atomic nuclei is studied by a comparison with selected experimental data. It is shown that the scattering of extrapolated HF values for the saturation density ?? obtained with various effective forces is largely due to a bad fit of many HF forces to experimental data. However, even after correcting the current parametrisations, an uncertainty remains for the value of ??, due to a correlation between the trends of anti ?(A) and the compression modulus K, which is reflected in the extrapolation to A=?. Using a generalised Skyrme functional, we show that this correlation is a particular case of a more general relation between anti ?(A) and the distribution of the binding energy between the inner and outer parts of the nuclear surface. Indications are given on possible improvements of the HF force by the inclusion of density- and momentum-dependent terms, supporting a value of ???0.158 fm-3 as well as in improved agreement between HF and droplet core densities. The relation of HF results with macroscopic models is discussed in Sect.5, showing the role played by exponential contributions, but also suggesting that dilation/compression effects exist, which are not taken into account in the usual energy density and droplet models. (orig.)

1986-01-01

276

Pion absorption in excited nuclear matter

International Nuclear Information System (INIS)

The target dependence and azimuthal correlations of protons and pions 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.)

1992-07-20

277

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.)

1991-11-11

278

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 re-examined with an emphasis on the reliability of various sum rules. Monitoring the continuum contribution and the convergence of the operator product expansion plays 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. (author). 37 refs., 6 figs

1995-01-01

279

J/{Psi} mass shift in nuclear matter

Energy Technology Data Exchange (ETDEWEB)

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.

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

280

Constraints on the skewness coefficient of symmetric nuclear matter

Within the nonlinear relativistic mean field model, we show that both the pressure of symmetric nuclear matter at supra-saturation densities and the maximum mass of neutron stars are sensitive to the skewness coefficient $J_0$ of symmetric nuclear matter. Using experimental constraints on the pressure of symmetric nuclear matter at supra-saturation densities from flow data in heavy ion collisions and the astrophysical observation of a large mass neutron star PSR J0348+0432, with the former favoring a smaller $J_0$ while the latter a larger $J_0$, we extract a constraint of $-494 MeV \\leq J_0 \\leq -10 MeV$. This constraint is compared with the results obtained in other analyses.

Cai, Bao-Jun

2014-01-01

281

Chemical and mechanical instability in warm and dense nuclear matter

Digital Repository Infrastructure Vision for European Research (DRIVER)

We investigate the possible thermodynamic instability in a warm and dense nuclear medium (T<50 MeV and \\rho_0<\\rho_B< 3\\rho_0) where a phase transition from nucleonic matter to resonance-dominated Delta-matter can take place. The analysis is performed by requiring the global conservation of baryon and electric charge numbers in the framework of a relativistic equation of state. Similarly to the liquid-gas phase transition, we show that the nucleon-Delta matter phase transiti...

Lavagno, A.; Pigato, D.

2012-01-01

282

Lectures notes on phase transformations in nuclear matter

The atomic nucleus, despite of being one of the smallest objects found in nature, appears to be large enough to experience phase transitions. The book deals with the liquid and gaseous phases of nuclear matter, as well as with the experimental routes to achieve transformation between them.Theoretical models are introduced from the ground up and with increasing complexity to describe nuclear matter from a statistical and thermodynamical point of view. Modern critical phenomena, heavy ion collisions and computational techniques are presented while establishing a linkage to experimental data.The

López, Jorge A

2000-01-01

283

Short range correlations in nuclear matter at equilibrium

International Nuclear Information System (INIS)

In this paper the effects of short-range correlations on the single-particle spectral functions, the occupation probabilities and the pair distribution functions of nuclear matter are studied. Calculations have been performed in the framework of Green functions and variational theories, whose main characteristics are briefly discussed. Semirealistic interactions derived from the Reid's soft-core interaction have been used. The momentum distribution is calculated in several ways showing in all cases a depletion of about 13% around normal nuclear matter densities. The effects of the statistical and short-range correlations on the different pair distribution functions are compared

1990-06-28

284

Nuclear Physics the core of matter, the fuel of stars.

Energy Technology Data Exchange (ETDEWEB)

Dramatic progress has been made in all branches of physics since the National Research Council's 1986 decadal survey of the field. The Physics in a New Era series explores these advances and looks ahead to future goals. The series includes assessments of the major subfields and reports on several smaller subfields, and preparation has begun on an overview volume on the unity of physics, its relationships to other fields, and its contributions to national needs. Nuclear Physics is the latest volume of the series. The book describes current activity in understanding nuclear structure and symmetries, the behavior of matter at extreme densities, the role of nuclear physics in astrophysics and cosmology, and the instrumentation and facilities used by the field. It makes recommendations on the resources needed for experimental and theoretical advances in the coming decade. Nuclear physics addresses the nature of matter making up 99.9 percent of the mass of our everyday world. It explores the nuclear reactions that fuel the stars, including our Sun, which provides the energy for all life on Earth. The field of nuclear physics encompasses some 3,000 experimental and theoretical researchers who work at universities and national laboratories across the United States, as well as the experimental facilities and infrastructure that allow these researchers to address the outstanding scientific questions facing us. This report provides an overview of the frontiers of nuclear physics as we enter the next millennium, with special attention to the state of the science in the United States.The current frontiers of nuclear physics involve fundamental and rapidly evolving issues. One is understanding the structure and behavior of strongly interacting matter in terms of its basic constituents, quarks and gluons, over a wide range of conditions - from normal nuclear matter to the dense cores of neutron stars, and to the Big Bang that was the birth of the universe. Another is to describe quantitatively the properties of nuclei, which are at the centers of all atoms in our world, in terms of models derived from the properties of the strong interaction. These properties include the nuclear processes that fuel the stars and produce the chemical elements. A third active frontier addresses fundamental symmetries of nature that manifest themselves in the nuclear processes in the cosmos, such as the behavior of neutrinos from the Sun and cosmic rays, and in low-energy laboratory tests of these symmetries. With recent developments on the rapidly changing frontiers of nuclear physics the Committee on Nuclear Physics is greatly optimistic about the next ten years. Important steps have been taken in a program to understand the structure of matter in terms of quarks and gluons.

Schiffer, J. P.; Physics

1999-01-01

285

From light nuclei to nuclear matter the role of relativity?

Energy Technology Data Exchange (ETDEWEB)

The success of non-relativistic quantum dynamics in accounting for the binding energies and spectra of light nuclei with masses up to A=10 raises the question whether the same dynamics applied to infinite nuclear matter agrees with the empirical saturation properties of large nuclei. The simple unambiguous relation between few-nucleon and many-nucleon Hamiltonians is directly related to the Galilean covariance of nonrelativistic dynamics. Relations between the irreducible unitary representations of the Galilei and Poincare groups indicate that the 'nonrelativistic' nuclear Hamiltonians may provide sufficiently accurate approximations to Poincare invariant mass operators. In relativistic nuclear dynamics based on suitable Lagrangeans the intrinsic nucleon parity is an explicit, dynamically relevant, degree of freedom and the emphasis is on properties of nuclear matter. The success of this approach suggests the question how it might account for the spectral properties of light nuclei.

Coester, F.; Physics

2003-11-10

286

From Light Nuclei to Nuclear Matter. The Role of Relativity?

The success of non-relativistic quantum dynamics in accounting for the binding energies and spectra of light nuclei with masses up to A=10 raises the question whether the same dynamics applied to infinite nuclear matter agrees with the empirical saturation properties of large nuclei.The simple unambiguous relation between few-nucleon and many-nucleon Hamiltonians is directly related to the Galilean covariance of nonrelativistic dynamics. Relations between the irreducible unitary representations of the Galilei and Poincare groups indicate thatthe ``nonrelativistic'' nuclear Hamiltonians may provide sufficiently accurate approximations to Poincare invariant mass operators. In relativistic nuclear dynamics based on suitable Lagrangeans the intrinsic nucleon parity is an explicit, dynamically relevant, degree of freedom and the emphasis is on properties of nuclear matter. The success of this approach suggests the question how it might account for the spectral properties of light nuclei.

Coester, F

2003-01-01

287

From light nuclei to nuclear matter the role of relativity?

International Nuclear Information System (INIS)

The success of non-relativistic quantum dynamics in accounting for the binding energies and spectra of light nuclei with masses up to A=10 raises the question whether the same dynamics applied to infinite nuclear matter agrees with the empirical saturation properties of large nuclei. The simple unambiguous relation between few-nucleon and many-nucleon Hamiltonians is directly related to the Galilean covariance of nonrelativistic dynamics. Relations between the irreducible unitary representations of the Galilei and Poincare groups indicate that the 'nonrelativistic' nuclear Hamiltonians may provide sufficiently accurate approximations to Poincare invariant mass operators. In relativistic nuclear dynamics based on suitable Lagrangeans the intrinsic nucleon parity is an explicit, dynamically relevant, degree of freedom and the emphasis is on properties of nuclear matter. The success of this approach suggests the question how it might account for the spectral properties of light nuclei

2001-07-09

288

Nuclear matter phase diagram from compound nucleus decay

Directory of Open Access Journals (Sweden)

Full Text Available The finite size of nuclei and the Coulomb interaction make it difficult to describe systems interacting through the strong force into thermodynamic terms. Our task is to extract the phase diagram of the theoretical infinite symmetrical uncharged nuclear matter from experiments of nuclear collisions where the systems are neither infinite, symmetrical, nor uncharged. Decay yields from such experiments are translated into coexistence densities and pressures by use of Fisher's droplet model. This method is tested on model systems such as the Ising model and a system of particles interacting via the Lennard-Jones potential. The specific problems inherent to nuclear reactions are considered. These include finite size effects, Coulomb repulsion, and the lack of a physical vapor in contact with a decaying system. Experimental data of compound nucleus experiments are studied within this framework, which is also shown to extend to higher energy reactions. Finally, the phase diagram of nuclear matter is extracted.

Lake P.T.

2012-02-01

289

Three-body properties in hot and dense nuclear matter

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Beyer, M.; Schadow, W.; Kuhrts, C.; Roepke, G.

1999-01-01

290

Final state interactions and hadron quenching in cold nuclear matter

Digital Repository Infrastructure Vision for European Research (DRIVER)

I examine the role of final state interactions in cold nuclear matter in modifying hadron production on nuclear targets with leptonic or hadronic beams. I demonstrate the extent to which available experimental data in electron-nucleus collisions can give direct information on final state effects in hadron-nucleus and nucleus-nucleus collisions. For hadron-nucleus collisions, a theoretical estimate based on a parton energy loss model tested in lepton-nucleus collisions shows ...

Accardi, Alberto

2007-01-01

291

Nuclear matter phase diagram from compound nucleus decay

Digital Repository Infrastructure Vision for European Research (DRIVER)

The finite size of nuclei and the Coulomb interaction make it difficult to describe systems interacting through the strong force into thermodynamic terms. Our task is to extract the phase diagram of the theoretical infinite symmetrical uncharged nuclear matter from experiments of nuclear collisions where the systems are neither infinite, symmetrical, nor uncharged. Decay yields from such experiments are translated into coexistence densities and pressures by use of Fisher's droplet model. This...

Moretto L.G.; Elliott J.B.; Lake P.T.; Phair L.

2012-01-01

292

Converting of Matter to Nuclear Energy by AB-Generator

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Alexander Bolonkin

2009-01-01

293

Pairing in bulk nuclear matter beyond BCS

The influence of short-range correlations on the spectral distribution of neutrons is incorporated in the solution of the gap equation for the ${}^3P_2-{}^3F_2$ 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 ${}^3P_2-{}^3F_2$ coupled channel either for all three realistic interactions although the pairing interaction becomes slightly more attractive.

Ding, D; Dickhoff, W H; Dussan, H; Rios, A; Polls, A

2014-01-01

294

Nuclear Forces and Nuclear Matter Including Pions and Isobars.

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 inclu...

F. Coester

1981-01-01

295

Inequalities for low-energy symmetric nuclear matter

Digital Repository Infrastructure Vision for European Research (DRIVER)

Using effective field theory we prove inequalities for the correlations of two-nucleon operators in low-energy symmetric nuclear matter. For physical values of operator coefficients in the effective Lagrangian, the S = 1, I = 0 channel correlations must have the lowest energy and longest correlation length in the two-nucleon sector. This result is valid at nonzero density and temperature.

Lee, Dean

2004-01-01

296

Phase transitions of nuclear matter beyond mean field theory

International Nuclear Information System (INIS)

The Cornwall-Jackiw-Tomboulis (CJT) effective action approach is applied to study the phase transition of nuclear matter modeled by the four-nucleon interaction. It is shown that in the Hartree-Fock approximation (HFA) a first-order phase transition takes place at low temperature, whereas the phase transition is of second order at higher temperature

2007-10-01

297

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 parameterizations of the Skyrme interaction, alpha-clustering effects at low densities in nuclear matter

1977-01-01

298

The coexistence curve of finite charged nuclear matter

International Nuclear Information System (INIS)

The multifragmentation data of the ISiS Collaboration and the EOS Collaboration are examined. Fisher's droplet formalism, modified to account for Coulomb energy, is used to determine the critical exponents ? and ?, the surface energy coefficient c0, the pressure-temperature-density coexistence curve of finite nuclear matter and the location of the critical point

2001-08-03

299

Phase transitions in nuclear matter. Formation conditions and experimental signals

International Nuclear Information System (INIS)

The nuclear collisions at different energies offer conditions to excite fundamental nuclear matter and some phase transitions could appear. The phase transition type is related to the collision energy, as well as to the collision geometry. The two aspects involve associated de Broglie wavelength and the mean free path. Depending on the relationships of the two quantities with the nuclear radius and the internucleonic distance different excitation mechanisms can be supposed. Diverse phase transition can be considered in connection with these excitation mechanisms. Therefore, a discussion on the correlation between phase transition type and excitation mechanisms is useful to establish formation conditions and experimental signatures. An important stage in this discussion is related to the energy range where different phase transitions are more or less probable. The energy dependencies for some interesting physical quantities could reflect such energy ranges for a few phase transitions. The aspects related to the influences of effectiveness of the nuclear structure are important, too. The present work discusses all these aspects of the phase transitions in nuclear matter. They are reviewed and analysed in the terms of the present experimental results. The formation conditions and experimental signals for four phase transitions - nuclear liquid-vapour, resonance matter, hadronic plasma and quark-gluon plasma - are presented in the paper. Some new aspects related to the quark-gluon plasma formation in Au-Au collisions at the energies available at RHIC-BNL(USA) are included, too. A special attention will be done to the antiproton regeneration mechanisms in highly excited nuclear matter as signals of a phase transition. These considerations include mainly the author results obtained in different collaborations (SKM 200 - JINR Dubna, MULTI - KEK Tsukuba, UB - RIKEN Tokyo, BRAHMS - BNL Upton, New York). (author)

2002-05-31

300

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

2004-01-01

301

Matter in extremis: Ultrarelativistic nuclear collisions at RHIC

Energy Technology Data Exchange (ETDEWEB)

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.

Jacobs, Peter; Wang, Xin-Nian

2004-08-20

302

Quasiparticle light elements and quantum condensates in nuclear matter

International Nuclear Information System (INIS)

Nuclei in dense matter are influenced by the medium. In the cluster mean field approximation, an effective Schrodinger equation for the A-particle cluster is obtained accounting for the effects of the surrounding medium, such as self-energy and Pauli blocking. Similar to the single-baryon states (free neutrons and protons), the light elements (2 ? A ? 4, internal quantum state ?) are treated as quasiparticles with energies EA,?(P; T, nn, np) that depend on the center of mass momentum P-vector , the temperature T, and the total densities nn, np of neutrons and protons, respectively. We consider the composition and thermodynamic properties of nuclear matter at low densities. At low temperatures, quartetting is expected to occur. Consequences for different physical properties of nuclear matter and finite nuclei are discussed.

2011-09-16

303

Quasiparticle light elements and quantum condensates in nuclear matter

Energy Technology Data Exchange (ETDEWEB)

Nuclei in dense matter are influenced by the medium. In the cluster mean field approximation, an effective Schrodinger equation for the A-particle cluster is obtained accounting for the effects of the surrounding medium, such as self-energy and Pauli blocking. Similar to the single-baryon states (free neutrons and protons), the light elements (2 {<=} A {<=} 4, internal quantum state {nu}) are treated as quasiparticles with energies E{sub A,{nu}}(P; T, n{sub n}, n{sub p}) that depend on the center of mass momentum P-vector , the temperature T, and the total densities n{sub n}, n{sub p} of neutrons and protons, respectively. We consider the composition and thermodynamic properties of nuclear matter at low densities. At low temperatures, quartetting is expected to occur. Consequences for different physical properties of nuclear matter and finite nuclei are discussed.

Roepke, G, E-mail: gerd.roepke@uni-rostock.de [Universitaet Rostock, Institut fuer Physik, 18051 Rostock (Germany)

2011-09-16

304

Coupled-cluster studies of infinite nuclear matter

Background: Coupled-cluster (CC) theory is a widely used many-body method for studying strongly correlated many-fermion systems. It allows for systematic inclusions of complicated many-body correlations beyond a mean field. Recent applications to finite nuclei have shown that first-principles approaches like CC theory can be extended to studies of medium-heavy nuclei, with excellent agreement with experiment. However, CC calculations of properties of infinite nuclear matter are rather few and date back more than 30 yr.Purpose: The aim of this work is thus to develop the relevant formalism for performing CC calculations in nuclear matter and neutron-star matter, including thereby important correlations to infinite order in the interaction and testing modern nuclear forces based on chiral effective field theory. Our formalism includes also the exact treatment of the so-called Pauli operator in a partial-wave expansion of the equation of state.Methods: Nuclear- and neutron-matter calculations are done using a coupled particle-particle and hole-hole ladder approximation. The coupled ladder equations are derived as an approximation of CC theory, leaving out particle-hole and nonlinear diagrams from the CC doubles amplitude equation. This study is a first step toward CC calculations for nuclear and neutron matter.Results: We present results for both symmetric nuclear matter and pure neutron matter employing state-of-the-art nucleon-nucleon interactions based on chiral effective field theory. We employ also the newly optimized chiral interaction [Ekström , Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.110.192502 110, 192502 (2013)] to study infinite nuclear matter. The ladder approximation method and corresponding results are compared with conventional Brueckner-Hartree-Fock theory. The ladder approximation is derived and studied using both exact and angular-averaged Pauli exclusion operators, with angular-averaged input momenta for the single-particle potentials in all calculations. The inclusion of an exact treatment of the Pauli operators in a partial-wave expansion yields corrections of the order of 1.7%-2% of the total energy in symmetric nuclear matter. Similarly, the inclusion of both hole-hole and particle-particle ladders result in corrections of the order 0.7%-2% compared to the approximation with only particle-particle ladders. Including these effects, we get at most almost a 6% difference between our CC calculation and the standard Brueckner-Hartree-Fock approach.Conclusions: We have performed CC calculations of symmetric nuclear matter and pure neutron matter including particle-particle and hole-hole diagrams to infinite order using an exact Pauli operator and angular-averaged single-particle energies. The contributions from hole-hole diagrams and exact Pauli operators add important changes to the final energies per particle.

Baardsen, G.; Ekström, A.; Hagen, G.; Hjorth-Jensen, M.

2013-11-01

305

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)

1981-01-17

306

Open charm tomography of cold nuclear matter

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...

Vitev, I; Johnson, M B; Qiu, J W

2006-01-01

307

Collective effects on transport coefficients of relativistic nuclear matter

In order to evaluate qualitatively and in order of magnitude the result of some collective effects on dense matter, a specific model is studied: the Walecka's model of nuclear matter. In this model, the meson fields contribute to the various observables in the Hartree approximation only while all correlations give rise to a collision term considered in the relaxation-time approximation. Within these approximations, a transport equation is given and solved in the Chapman-Enskog expansion in first order. The main transport coefficients (thermal conductivity, shear and bulk viscosities) are calculated and compared to the results first obtained by Anderson and Witting.

Hakim, Rémi; Mornas, Lysiane

1993-06-01

308

Pairing correlations in nuclear matter with realistic interactions

International Nuclear Information System (INIS)

Some aspects of the superfluidity in nuclear matter and neutron matter are numerically investigated by using realistic interactions. It is shown that the gap equation with bare pairing interaction contains the particle-particle correlations corresponding to the ladder diagrams. The effects of the short range part of the interaction on the gap function are discussed in momentum space in connection with the weak coupling approximation. Extending the BCS theory to coupled channels, it is found that the pairing between neutron and proton in the 3S1-3D1 channel is surprisingly large, of the order of about 10 MeV. ((orig.))

1994-07-01

309

The ?? cloud contribution to the ? width in nuclear matter

International Nuclear Information System (INIS)

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(?),??N(?), and 2-body absorptions ?NN?NN(?),?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

2014-02-05

310

The ?? cloud contribution to the ? width in nuclear matter

Energy Technology Data Exchange (ETDEWEB)

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.

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

311

From nuclei to nuclear matter - a statistical model

International Nuclear Information System (INIS)

Full text: The equation of state and the composition of hot hadronic matter is described by an ensemble of nuclei and interacting nucleons in nuclear statistical equilibrium. The nucleons are described with a relativistic mean field model and the masses of the nuclei are taken from nuclear structure calculations which are based on the same nuclear Lagrangian. For known nuclei experimental data is used directly. Excluded volume effects are implemented in a thermodynamic consistent way to be able to describe the transition to uniform nuclear matter. The resulting equation of state is presented and a good agreement with other commonly used models based on the single nucleus approximation is found. Regarding the composition the importance of a statistical treatment is illustrated and the role of the shell effects is investigated. Special emphasis is put on the light clusters which e.g. under certain conditions are only poorly represented by alpha particles. The important influence of the composition on the nucleosynthesis and on the neutrino dynamics and their spectra suggest the use of a grand canonical description of supernova matter. (author)

2009-01-18

312

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.

2010-01-01

313

Equation of state of symmetric nuclear matter and neutron matter with three body forces

International Nuclear Information System (INIS)

Microscopic optical potential calculated within first order Brueckner theory has been extensively used to calculate saturation properties of zero temperature symmetric nuclear matter (SNM), pure neutron matter(PNM) and analyze the nucleon scattering data. In this paper we confine ourselves to only the saturation property of SNM and PNM. We have used soft core Urbana v14 (UV14) and Hard core Hamada Johnston (HJ) inter-nucleon potential in the present work. No inter-nucleon potential has been successful in obtaining the correct binding energy and saturation density in the non relativistic BHF approximation

2011-12-01

314

Triplet seesaw model: from inflation to asymmetric dark matter and leptogenesis

The nature of dark matter (DM) particles and the mechanism that provides their measured relic abundance are currently unknown. Likewise, the nature of the inflaton is unknown as well. We investigate the triplet seesaw model in an unified picture. At high energy scale, we consider Higgs inflation driven by an admixture of standard model and triplet Higgs fields, both coupled non-minimally to gravity. At intermediate and low energies we investigate vector like fermion doublet DM candidates with a charge asymmetry in the dark sector, which is generated by the same mechanism that provides the baryon asymmetry, namely baryogenesis-via-leptogenesis induced by the decay of scalar triplets. At the same time the model gives rise to neutrino masses in the ballpark of oscillation experiments via type-II seesaw. We then apply Bayesian statistics to infer the model parameters giving rise to the observed baryon asymmetry and DM density, compatibly with inflationary and DM direct detection constraints, updated with the CRES...

Arina, Chiara

2012-01-01

315

Appearance of the Gyroid Network Phase in Nuclear Pasta Matter

Nuclear matter under the conditions of a supernova explosion unfolds into a rich variety of spatially structured phases, called nuclear pasta. We investigate the role of periodic networklike structures with negatively curved interfaces in nuclear pasta structures, by static and dynamic Hartree-Fock simulations in periodic lattices. We investigate particularly the role of minimal surfaces in that context. As the most prominent result, we identify the single gyroid network structure of cubic chiral symmetry, a well known configuration in nanostructured softmatter systems, both as a dynamical state and as a cooled static solution. While most observed gyroids are only meta-stable, the very small energy differences to the ground state indicate its relevance for structures in nuclear pasta.

Schuetrumpf, B; Iida, K; Schroeder-Turk, G E; Maruhn, J A; Mecke, K; Reinhard, P -G

2014-01-01

316

Climate Change, Nuclear Power and Nuclear Proliferation: Magnitude Matters

Energy Technology Data Exchange (ETDEWEB)

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.

Robert J. Goldston

2011-04-28

317

Strange matter - a new domain of nuclear physics

Energy Technology Data Exchange (ETDEWEB)

Relativistic heavy ion collisions offer the exciting possibility to produce exotic (meta-)stable states of nuclear matter containing (roughly) equal number of strangeness compared to the content in baryon number: Strangelets, i.e. small pieces of strange quark matter (SQM), were proposed as a signal of QGP formation. However, as their hadronic counterpart, also new multihypernuclear objects, i.e. small pieces of strange hadronic matter (SHM), may show up with rather very similar properties. This observation gives raise to the speculation that both states might have a strong overlap and correlation. In this overview we review the reasoning of both their stability and existence, the possible separation of strangeness necessary for their formation and the chances for their detection. (orig.)

Greiner, C. [Dept. of Physics, Duke Univ., Durham, NC (United States); Diener, A. [Inst. fuer Theoretische Physik, Frankfurt Univ. (Germany); Schaffner, J. [Inst. fuer Theoretische Physik, Frankfurt Univ. (Germany); Stoecker, H. [Inst. fuer Theoretische Physik, Frankfurt Univ. (Germany)

1994-01-03

318

Phase structure in a chiral model of nuclear matter

International Nuclear Information System (INIS)

The phase structure of symmetric nuclear matter in the extended Nambu-Jona-Lasinio (ENJL) model is studied by means of the effective potential in the one-loop approximation. It is found that chiral symmetry gets restored at high nuclear density and a typical first-order phase transition of the liquid-gas transition occurs at zero temperature, T=0, which weakens as T grows and eventually ends up with a second-order critical point at T=20 MeV. This phase transition scenario is confirmed by investigating the evolution of the effective potential versus the effective nucleon mass and the equation of state.

2011-08-01

319

Finite size effects in Neutron Star and Nuclear matter simulations

In this work we study molecular dynamics simulations of symmetric nuclear matter using a semi-classical nucleon interaction model. 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 shaped by artificial aspects of the simulations. We explore different geometries for the periodic boundary conditions imposed on the simulation cell: cube, hexagonal prism and truncated octahedron. We find that different cells may yield different solutions for the same physical conditions (i.e. density and temperature). The particular shape of the solution at a given density can be predicted analytically by energy minimization. We also show that even if this behavior is due to finite size effects, it does not mean that it vanishes for very large systems and it actually is independent of the system size: The system size sets the only characteristic length scale for the inhomogeneitie...

Molinelli, P A Giménez

2014-01-01

320

The Coester Line in Relativistic Mean Field Nuclear Matter

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 at equilibrium densities. We investigated the existence of a linear correlation between $B_N$ and $\\rho_0$, 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.

Delfino, A; Timoteo, V S; Martins, J S S

2005-01-01

321

The Coester Line in Relativistic Mean Field Nuclear Matter

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 at equilibrium densities. We investigated the existence of a linear correlation between $B_N$ and $\\rho_0$, 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.

Delfino, A.; Malheiro, M.; Timóteo, V. S.; Martins, J. S. Sá

2005-03-01

322

The Coester line in relativistic mean field nuclear matter

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english 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.

A., Delfino; M., Malheiro; V. S., Timóteo; J. S. Sá, Martins.

323

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.)

1993-01-01

324

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, and kaonic atoms formation. These studies explore kaon-nucleon and hyperon-nucleon forces at very low energy, the nuclear shell model in the 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 detailed descriptions of the two detectors. (author)

1997-12-01

325

Non-Abelian energy loss in cold nuclear matter

We use a formal recurrence relation approach to multiple parton scattering to find the complete solution to the problem of medium-induced gluon emission from partons propagating in cold nuclear matter. The differential bremsstrahlung spectrum, where Landau-Pomeranchuk-Migdal destructive interference effects are fully accounted for, is calculated for three different cases: (1) a generalization of the incoherent Bertsch-Gunion solution for asymptotic on-shell jets, (2) initial-state energy loss of incoming jets that undergo hard scattering and (3) final-state energy loss of jets that emerge out of a hard scatter. Our analytic solutions are given as an infinite opacity series, which represents a cluster expansion of the sequential multiple scattering. These new solutions allow, for the first time, direct comparison between initial- and final-state energy loss in cold nuclei. We demonstrate that, contrary to the naive assumption, energy loss in cold nuclear matter can be large. Numerical results to first order in...

Vitev, I

2007-01-01

326

Nuclear matter equation of state and neutron star oscillations

International Nuclear Information System (INIS)

Neutron stars are born when a massive star runs out of nuclear fuel and undergoes a supernova explosion in which the core of the star collapses to form a compact object, containing about one and a half times of solar mass inside a sphere of radius about ten kilometers. Due to various perturbations, radial and non-radial waves travel through the star interior, that make the surface oscillate. The nonradial oscillations of neutron stars make them promising sources of detectable gravitational waves. The structure and oscillation modes of neutron stars are governed by the equation of state of the hadronic matter. The study of the vibrational motion of neutron stars has become an important tool to constrain the equation of state of nuclear matter. In this section we present the formalism of calculating normal mode frequencies of non-radial oscillations

2009-12-08

327

Low densities in nuclear and neutron matters and in the nuclear surface

Digital Repository Infrastructure Vision for European Research (DRIVER)

Nuclear and neutron matters are investigated in the low density region, well below the nuclear saturation density. Microscopic calculations, based on the Bethe-Brueckner approach with a few realistic nucleon-nucleon potentials, are compared with the predictions of a set of phenomenological effective interactions, mostly employed in nuclear structure studies. An energy functional is constructed on the basis of the microscopic bulk EoS and applied to a selection of nuclei thro...

Baldo, M.; Maieron, C.; Schuck, P.; Vinas, X.

2004-01-01

328

Two-particle properties in nuclear matter at finite temperatures

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 condensa...

Roepke, G.; Schnell, A.

1998-01-01

329

Binding energy per nucleon and hadron properties in nuclear matter

Digital Repository Infrastructure Vision for European Research (DRIVER)

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, ...

Yakhshiev, Ulugbek; Kim, Hyun-chul

2010-01-01

330

Quark mean field theory and consistency with nuclear matter

International Nuclear Information System (INIS)

1/N_c expansion in QCD (with N_c the number of colours) suggests using a potential from meson sector (e.g. Richardson) for baryons. For light quarks a ? field has to be introduced to ensure chiral symmetry breaking (_?SB). It is found that nuclear matter properties can be used to pin down the _?SB-modelling. All masses, M_?, m_?, m_? are found to scale with density. The equations are solved self consistently. (author)

1989-01-01

331

Effects of Meson Mass Decrease on Superfluidity in Nuclear Matter

Digital Repository Infrastructure Vision for European Research (DRIVER)

We calculate the $^1S_0$ pairing gap in nuclear matter by adopting the "in-medium Bonn potential" proposed by Rapp et al. [e-print nucl-th/9706006], which takes into account the in-medium meson mass decrease, as the particle-particle interaction in the gap equation. The resulting gap is significantly reduced in comparison with the one obtained by adopting the original Bonn potential.

Matsuzaki, Masayuki; Tanigawa, Tomonori

1998-01-01

332

Effects of meson mass decrease on superfluidity in nuclear matter

We calculate the $^1S_0$ pairing gap in nuclear matter using a relativistic model by adopting the "in-medium Bonn potential" proposed by Rapp et al. [e-print nucl-th/9706006], which conforms to the Brown-Rho scaling, as the particle-particle interaction in the gap equation. The resulting gap is significantly reduced in comparison with the one obtained by adopting the original Bonn potential.

Matsuzaki, M; Matsuzaki, Masayuki; Tanigawa, Tomonori

1999-01-01

333

Effect of meson mass decrease on superfluidity in nuclear matter

Energy Technology Data Exchange (ETDEWEB)

{sup 1}S{sub 0} pairing in symmetric nuclear matter is studied by taking the hadron mass decrease into account via the 'In-Medium Bonn potential' which was recently proposed by Rapp et al. The resulting gap is significantly reduced in comparison with the one obtained with the original Bonn-B potential and we ascertain that the meson mass decrease is mainly responsible for this reduction. (author)

Tanigawa, Tomonori [Kyushu Univ., Fukuoka (Japan). Dept. of Physics; Matsuzaki, Masayuki [Department of Physics, Fukuoka University of Education, Munakata, Fukuoka (Japan)

2000-01-01

334

Effects of meson mass decrease on superfluiding in nuclear matter

Energy Technology Data Exchange (ETDEWEB)

{sup 1}S{sub 0} pairing in nuclear matter is investigated by taking the hadron mass decrease into account via the 'In-Medium Bonn potential' which was recently proposed by Rapp et al. The resulting gap is significantly reduced in comparison with the one obtained with the original Bonn-B potential and we ascertain that the meson mass decrease is mainly responsible for this reduction. (author)

Tanigawa, T. [Kyushu Univ., Faculty of Science, Fukuoka (Japan); Matsuzaki, M.

1999-08-01

335

Landau-Pomeranchuk-Migdal effect for nuclear matter in QCD

Digital Repository Infrastructure Vision for European Research (DRIVER)

Soft photon and gluon radiation off a fast quark propagating through nuclear matter is discussed. The close anology between the Landau - Pomeranchuk - Migdal (LPM) effect in QED and the emission of soft gluons, suggested in ref. \\cite{BDPS} for ``hot" plasma, is confirmed and the relation between Mueller's approach and traditional calculations is established. It is shown that perturbative QCD can be applied to take into account the LPM coherent suppression both for photon an...

Levin, Eugene

1995-01-01

336

The symmetry energy in nuclei and in nuclear matter

Digital Repository Infrastructure Vision for European Research (DRIVER)

We discuss to what extent information on ground-state properties of finite nuclei (energies and radii) can be used to obtain constraints on the symmetry energy in nuclear matter and its dependence on the density. The starting point is a generalized Weizsäcker formula for ground-state energies. In particular effects from the Wigner energy and shell structure on the symmetry energy are investigated. Strong correlations in the parameter space prevent a clear isolation of the surface contributio...

2006-01-01

337

Time characteristics for the spinodal decomposition in nuclear matter

International Nuclear Information System (INIS)

Dynamics of the fluctuation growth are studied. Time characteristics are key quantities to determine the conditions under which spinodal decomposition could be observed. Dynamical instabilities arising from fluctuations in spinodal zone for nuclear matter are studied using Skyrme type interactions within a pseudo-particle model. Typical times for cluster formation are extracted. The numerical treatment is based on the Vlasov phase space transport equation. (K.A.) 11 refs.; 7 figs

1992-01-01

338

The ? potential in nuclear matter from a realistic interaction

International Nuclear Information System (INIS)

Previous studies on the nuclear matter properties have shown the relevance of the ? isobar degrees of freedom, as well as the need of an accurate estimate of the corresponding ? potential. Motivated by this result, we have calculated the potential energy of the ? isobar in nuclear matter with the same model nucleon-nucleon interaction, the Argonne v28, which was previously used in the study of nuclear matter. This potential includes all possible transitions from NN states to N? and ?? ones, and give an excellent fit to nucleon-nucleon phenomenological phase shifts and deuteron properties. All diagrams with one nucleon hole-line are summed up in the framework of a G-matrix approach. The ? potential so obtained was found to be weakly attractive at low density, becoming repulsive at increasing density with a value of 50 MeV at saturation. The repulsive potential receives the main contribution from the isotopic spin T=2 channels and it appears to be in contradiction with the phenomenology on ? production in nuclei. The sensitivity to possible simple modifications of the potential is explored and it is concluded that complete refitting of the parameters would be necessary in order to remove the contradiction with phenomenology, while keeping the agreement with nucleon-nucleon data. This result indicates the strong constraints that the phenomenology on the ? isobar imposes on any realistic nucleon-nucleon potential, to be used in self-consistent calculations of nuclear matter properties, which include ? degrees of freedom. Possible improvements of the interaction are briefly indicated. ((orig.))

1994-07-01

339

Analysis of Boltzmann-Langevin Dynamics in Nuclear Matter

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 correla...

Ayik, S.; Chomaz, Ph; Colonna, M.; Randrup, J.

1995-01-01

340

Heating of nuclear matter and multifragmentation : antiprotons vs. pions.

Energy Technology Data Exchange (ETDEWEB)

Heating of nuclear matter with 8 GeV/c {bar p} and {pi}{sup {minus}} beams has been investigated in an experiment conducted at BNL AGS accelerator. All charged particles from protons to Z {approx_equal} 16 were detected using the Indiana Silicon Sphere 4{pi} array. Significant enhancement of energy deposition in high multiplicity events is observed for antiprotons compared to other hadron beams. The experimental trends are qualitatively consistent with predictions from an intranuclear cascade code.

Back, B.; Beaulieu, L.; Breuer, H.; Gushue, S.; Hsi, W.-C.; Korteling, R. G.; Kwiatkowski, K.; Laforest, R.; Lefort, T.; Martin, E.; Pienkowski, L.; Ramakrishnan, E.; Remsberg, L. P.; Rowland, D.; Ruangma, A.; Viola, V. E.; Winchester, E.; Yennello, S. J.

1999-05-03

341

Heating of nuclear matter and multifragmentation: antiprotons vs. pions

International Nuclear Information System (INIS)

Heating of nuclear matter with 8 GeV/c bar p and ?- beams has been investigated in an experiment conducted at BNL AGS accelerator. All charged particles from protons to Z ? 16 were detected using the Indiana Silicon Sphere 4? array. Significant enhancement of energy deposition in high multiplicity events is observed for antiprotons compared to other hadron beams. The experimental trends are qualitatively consistent with predictions from an intranuclear cascade code

1999-01-09

342

?NN correlations and the ?-particle binding in nuclear matter

International Nuclear Information System (INIS)

The ? particle energy in nuclear matter is calculated with separable S state ?N and NN potentials of Puff's type. By solving the Bethe-Faddeev equations, the three-body ?NN cluster energy Esub(?3) is calculated with the repulsive result Esub(?3) approximately equal to 3-4 MeV, which is less than 10% of the magnitude of the two-body ?N cluster energy. The result suggests a satisfactory convergence of the reaction matrix method of calculating Bsub(?). (author)

1980-01-01

343

Probing nuclear matter with dielectrons - results from the Bevalac

Energy Technology Data Exchange (ETDEWEB)

The use of dielectrons to probe extreme conditions in nuclear matter is discussed. Earlier results from p-A and A-A studies by the Dilepton Spectrometer (DLS) collaboration at the Bevalac are briefly reviewed. Preliminary results on the yield of dielectrons in p-p and p-d interactions at 1.0 and 4.9 GeV are presented. Future directions of the DLS program, with the expectation of higher statistics, is outlined. (orig.).

Schroeder, L.S. (Lawrence Berkeley Lab., Univ. California, CA (United States))

1992-03-09

344

Pairing effects in low density domain of nuclear matter

International Nuclear Information System (INIS)

Using equations, governing np pairing correlations in S=1, T=0 pairing channel (PRC 63 (2001) 021304(R)), it is shown that at low densities equations for the energy gap in the spectrum of quasiparticles and chemical potentials of protons and neutrons allow solutions with negative chemical potential. This corresponds to appearance of Bose-Einstein condensate (BEC) of deuterons in low density region of nuclear matter

2004-04-05

345

Pairing effects in low density domain of nuclear matter

Energy Technology Data Exchange (ETDEWEB)

Using equations, governing np pairing correlations in S=1, T=0 pairing channel (PRC 63 (2001) 021304(R)), it is shown that at low densities equations for the energy gap in the spectrum of quasiparticles and chemical potentials of protons and neutrons allow solutions with negative chemical potential. This corresponds to appearance of Bose-Einstein condensate (BEC) of deuterons in low density region of nuclear matter.

Isayev, A.A.; Bastrukov, S.I.; Yang, J

2004-04-05

346

Pairing effects in low density domain of nuclear matter

Using equations, governing np pairing correlations in S=1, T=0 pairing channel (PRC 63 (2001) 021304(R)), it is shown that at low densities equations for the energy gap in the spectrum of quasiparticles and chemical potentials of protons and neutrons allow solutions with negative chemical potential. This corresponds to appearance of Bose--Einstein condensate (BEC) of deuterons in low density region of nuclear matter.

Isayev, A A; Yang, J

2004-01-01

347

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

1990-01-01

348

High-density nuclear matter with nonlocal confining solitons

Digital Repository Infrastructure Vision for European Research (DRIVER)

An infinite system of nonlocal, individually confining solitons is considered as a model of high-density nuclear matter. The soliton-lattice problem is discussed in the Wigner-Seitz approximation. The cell size is varied to study the density dependence of physical quantities of interest. A transition to a system where quarks can migrate between solitons is found. We argue that this signals quark deconfinement. The model is applied to the calculation of selected in-medium pro...

Johnson, Charles W.; Fai, George

1997-01-01

349

Saturated symmetric nuclear matter in strong magnetic fields

Strongly magnetized symmetric nuclear matter is investigated within the context of effective baryon-meson exchange models. The magnetic field is coupled to the charge as well as the dipole moment of the baryons by including the appropriate terms in the Lagrangian density. The saturation density of magnetized, symmetric nuclear matter ?0(B) was calculated for magnetic fields of the order of 1017 gauss. For the calculated range of ?0(B) the binding energy, symmetry energy coefficient a4, and compressibility K of nuclear matter were also calculated. It is found that with an increasing magnetic field ?0(B) increases, while the system becomes less bound. Furthermore, the depopulation of proton Landau levels leaves a distinct fluctuating imprint on K and a4. The calculations were also performed for increased values of the baryon magnetic dipole moment. By increasing the dipole moment strength ?0(B) is found to decrease, but the system becomes more tightly bound while the fluctuations in K and a4 persist.

Diener, J. P. W.; Scholtz, F. G.

2013-06-01

350

Separable NN potentials from inverse scattering for nuclear matter studies

International Nuclear Information System (INIS)

Low-rank separable potentials greatly simplify perturbation-theory based many-body computations and are especially useful in finite temperature and nonequilibrium nuclear matter studies. With local potentials such calculations become very lengthy. In this paper, we present a first version of a separable potential constructed directly from available empirical nucleon-nucleon phase shifts (Elab3S1-3D1 channel, where the deuteron wave function serves as off-shell input at the binding energy. The simplest potential thus constructed in this channel has rank 4. The deuteron wave function is nevertheless empirically undetermined at high momenta, prompting us to adopt as well as construct several model wave functions that all fit the low momentum deuteron data while allowing variations at high momenta. The effects of these off-shell variations on predicted nuclear matter properties are discussed. No off-shell information is included in the other channels, leading to potentials of rank either 1 or 2. With this simple model potential we perform standard Brueckner nuclear matter ground state calculations and compare the results with Machleidt's using Bonn OBEP. The agreement is good in the S channels and in the singlet D2 channel. Other channels show larger discrepancies, the most significant of which coming from the 3P1 and 3D1 channels. These results are explained by the off-shell behavior of our model potential as compared to the Bonn OBEP. (Abstract Truncated)

1997-04-01

351

Parametrization of the relativistic ?-? model for nuclear matter

International Nuclear Information System (INIS)

We have investigated the zero-temperature equation of state (EoS) for infinite nuclear matter within the ?-? model at all densities nB and different proton-neutron asymmetry ??(N-Z)/A. We have presented an analytical expression for the compression modulus and found that nuclear matter ceases to saturate at ? slightly larger than 0.8. Afterward, we have developed an analytical method to determine the strong coupling constants from the EoS for isospin symmetric nuclear matter, which allow us to reproduce all the saturation properties with high accuracy. For various values of the nucleon effective mass and the compression modulus, we have found that the quartic self-coupling constant G4 is negative, or positive and very large. Furthermore, we have demonstrated that it is possible (a) to investigate the EoS in terms of nB and ?; and (b) to reproduce all the known saturation properties without G4. We have thus concluded that the latter is not necessary in the ?-? model.

2010-08-01

352

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.)

1994-03-01

353

International Nuclear Information System (INIS)

Nuclear electromagnetic moments of short-lived nuclei produced through the projectile fragmentation process in high energy heavy ion collisions have been determined by detecting ?-NM(Q)R of them implanted in various metals and ionic crystals to study nuclear structure. Using the nuclear moments as probes, internal electromagnetic fields in crystals have been experimentally and theoretically studied to clarify the electronic structures of the dilute impurities. In order to make concrete the understanding of the nuclear structure given by the nuclear moments, the nuclear matter distributions in the short-lived nuclei have also been determined by detecting reaction cross sections of the heavy ion collisions at intermediate beam energies. (author)

2004-07-01

354

Asymmetric Arginine dimethylation of Epstein-Barr virus nuclear antigen 2 promotes DNA targeting

International Nuclear Information System (INIS)

The Epstein-Barr virus (EBV) growth-transforms B-lymphocytes. The virus-encoded nuclear antigen 2 (EBNA2) is essential for transformation and activates gene expression by association with DNA-bound transcription factors such as RBPJ? (CSL/CBF1). We have previously shown that EBNA2 contains symmetrically dimethylated Arginine (sDMA) residues. Deletion of the RG-repeat results in a reduced ability of the virus to immortalise B-cells. We now show that the RG repeat also contains asymmetrically dimethylated Arginines (aDMA) but neither non-methylated (NMA) Arginines nor citrulline residues. We demonstrate that only aDMA-containing EBNA2 is found in a complex with DNA-bound RBPJ? in vitro and preferentially associates with the EBNA2-responsive EBV C, LMP1 and LMP2A promoters in vivo. Inhibition of methylation in EBV-infected cells results in reduced expression of the EBNA2-regulated viral gene LMP1, providing additional evidence that methylation is a prerequisite for DNA-binding by EBNA2 via association with the transcription factor RBPJ?.

2010-02-20

355

Modification of the ?-Meson Lifetime in Nuclear Matter

Information on hadron properties in the nuclear medium has been derived from the photoproduction of ? mesons on the nuclei C, Ca, Nb, and Pb using the Crystal Barrel/TAPS detector at the ELSA tagged photon facility in Bonn. The dependence of the ?-meson cross section on the nuclear mass number has been compared with three different types of models: a Glauber analysis, a Boltzmann-Uehling-Uhlenbeck analysis of the Giessen theory group, and a calculation by the Valencia theory group. In all three cases, the inelastic ? width is found to be 130 150MeV/c2 at normal nuclear matter density for an average 3-momentum of 1.1GeV/c. In the rest frame of the ? meson, this inelastic ? width corresponds to a reduction of the ? lifetime by a factor ?30. For the first time, the momentum dependent ?N cross section has been extracted from the experiment and is in the range of 70 mb.

Kotulla, M.; Trnka, D.; Mühlich, P.; Anton, G.; Bacelar, J. C. S.; Bartholomy, O.; Bayadilov, D.; Beloglazov, Y. A.; Bogendörfer, R.; Castelijns, R.; Crede, 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.

2008-05-01

356

Nuclear transparency effect in the strongly interacting matter

International Nuclear Information System (INIS)

There was a discussion that the results of study of the nuclear transparency effect in nuclear-nuclear collisions at relativistic and ultrarelativistic energies could help to extract the information on new phases of the strongly interacting matter as well as the QCD critical point. The results could provide further confirmation of the existence of the horn effect which had initially been obtained for the ratio of average values of ?+ - to ?+-mesons' multiplicity as a function of the initial energies in the NA49 SPS CERN experiment. To observe the horn as a function of centrality, the new more enriched experimental data are required. The data which are expected from NICA/MPD JINR and CBM GSI setups could fulfill the requirement

2011-10-01

357

Nuclear transparency effect in the strongly interacting matter

International Nuclear Information System (INIS)

It is discussed that the results of study of the nuclear transparency effect in nuclear-nuclear collisions at relativistic and ultrarelativistic energies could help to extract the information on new phases of the strongly interacting matter as well as the QCD critical point. The results could provide further confirmation of the existence of the horn effect which had initially been obtained for the ratio of average values of mesons multiplicity as a function of the initial energies in the NA49 SPS CERN experiment. To observe the horn as a function of centrality, the new more enriched experimental data are required. The data which are expected from NICA/MPD JINR and CBM GSI setups could fill the requirement

2011-10-01

358

Open charm in nuclear matter at finite temperature

We study the properties of open-charm mesons ($D$ and $\\bar {D}$) in nuclear matter at finite temperature within a self-consistent coupled-channel approach. The meson-baryon interactions are adopted from a type of broken SU(4) s-wave Tomozawa-Weinberg terms supplemented by an attractive scalar-isoscalar attraction. The in-medium solution at finite temperature incorporates Pauli blocking effects, mean-field binding on all the baryons involved, and $\\pi$ and open-charm meson self-energies in a self-consistent manner. In the $DN$ sector, the $\\Lambda_c$ and $\\Sigma_c$ resonances, generated dynamically at 2593 MeV and 2770 MeV in free space, remain close to their free-space position while acquiring a remarkable width due to the thermal smearing of Pauli blocking as well as from the nuclear matter density effects. As a result, the $D$ meson spectral density shows a single pronounced peak for energies close to the $D$ meson free-space mass that broadens with increasing matter density with an extended tail particula...

Tolos, Laura; Mizutani, Tetsuro

2007-01-01

359

Relativistic mean-field models and nuclear matter constraints

Energy Technology Data Exchange (ETDEWEB)

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.

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

360

Symmetry Energy of Nuclear Matter at Low Densities and Clustering at the Nuclear Surface

We present a density functional theory which connects nuclear matter equation of state, which incorporates clustering at low densities, with clustering in medium and heavy nuclei at the nuclear surface. This explains the large values of symmetry energy reported by Natowitz et al for densities IL2) which have been used in ab initio calculations in s- and p-shell nuclei and neutron matter. Theory predicts new situations and regimes to be explored both theoretically and experimentally. It is demonstrated that, due to clustering, the neutron skin thickness reduces significantly.

Sauli, Zaliman; Abdullah, Nooraihan; Anwar, K.; Usmani, Q. N.

2012-09-01

361

Converting of Matter to Nuclear Energy by AB-Generator

Directory of Open Access Journals (Sweden)

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.

Alexander Bolonkin

2009-01-01

362

Sound waves and solitons in hot and dense nuclear matter

Assuming that nuclear matter can be treated as a perfect fluid, we study the propagation of perturbations in the baryon density. The equation of state is derived from a relativistic mean field model, which is a variant of the non-linear Walecka model. The expansion of the Euler and continuity equations of relativistic hydrodynamics around equilibrium configurations leads to differential equations for the density fluctuations. We solve them numerically for linear and spherical perturbations and follow the time evolution of the initial pulses. For linear perturbations we find single soliton solutions and solutions with one or more solitons followed by radiation. Depending on the equation of state a strong damping may occur. Spherical perturbations are strongly damped and almost do not propagate. We study these equations also for matter at finite temperature. Finally we consider the limiting case of shock wave formation.

Fogaça, D A; Navarra, F S

2008-01-01

363

Effect of the ?(1236) resonance on NN scattering, nuclear matter and neutron matter

International Nuclear Information System (INIS)

A momentum-space nucleon-nucleon potential in the OBE frame is presented where part of the phenomenlogical sigma-contribution describing the intermediate range attraction is replaced by the twice-iterated pion-exchange potentials which couple the NN channel with the N?(1236) and ?? channels. For various strengths of these transition potentials (depending on a cutoff parameter), a sufficiently accurate description of NN data is obtained. These models are then used to calculate nuclear matter properties in first-order Brueckner theory. Due to the explicit treatment of the ?, there is a strong repulsive effect in all partial wave states. It turns out, however, that one does not come off the Coester band. In addition, neutron matter calculations at densities relevant for neutron stars are presented. It turns out that 80% of the total repulsive effect introduced by the ? arises in L>=1 partial wave states. (Auth.)

1977-04-18

364

Spin Instability in Nuclear Matter and the Skyrme Interaction

In the present work the problem of spin instability of nuclear matter with the Skyrme interaction is analyzed. The three-body part of the interaction is replaced by using a density dependent potential which is a modification to that given previously by Dabrowski. The symmetry energies are calculated and their rearrangement corrections. Good agreement is obtained with previous calculations.Translated AbstractSpininstabilität in Kernmaterie und Skyrme-WechselwirkungDie vorliegende Arbeit analysiert die Spininstabilität von Kernmaterie mit Skyrme-Wechselwirkung. Der Dreikörperanteil der Wechselwirkung ist durch ein dichteabhängiges Potential ersetzt. Die Symmetrieenergien und ihre Umordnungskorrekturen werden berechnet. Sie stimmen gut mit vorhergehenden Rechnungen überein.

Mansour, H. M. M.

365

Experimental Investigations of Clustering in Low Density Nuclear Matter

International Nuclear Information System (INIS)

The formation of clusters in low density matter formed in near Fermi energy heavy ion collisions has been investigated using the NIMROD multi-detector at Texas A and M University. Emphasis is on elucidation of the low density equation of state. Temperature and density dependent symmetry free energies derived from isoscaling analyses of the yields of nuclei with A?4 are far above those obtained in common effective interaction calculations, reflecting the cluster formation. A possible extensionof the experimental techniques to investigations of nuclear Bose condensates is also discussed.

2010-11-24

366

In-Medium phenomena in Low Density Nuclear Matter

International Nuclear Information System (INIS)

In-medium phenomena of low density nuclear matter are studied using collisions of 47 A MeV 40 Ar and 64 Zn projectiles with 112Sn and 124Sn target nuclei. Low density equations of state are tested by confronting various models with the data. In-medium cluster binding energies and symmetry density are also studied at low densities. We find that models that account for in-medium effects in general describe the data better than models that do not.

2013-03-25

367

Many body approach to quartet condensation in nuclear matter

International Nuclear Information System (INIS)

A self-consistent theory for quartet condensation in homogeneous infinite nuclear matter is proposed. It goes along similar lines as Gorkov theory for pairing. However, details and physical consequences are very different. For example in the quartet case no sharp quasi-particle pole develops in the single particle propagator. Also quartet condensation only exists in the BEC phase and no extended coherence length develops in weak coupling. The critical temperature for quartet condensation is also investigated in analogy to the Thouless criterion for pairing.

2011-09-16

368

Model-space nuclear matter calculations with the Bonn potential

International Nuclear Information System (INIS)

In this work the authors have examined a model-space Brueckner-Hartree-Fock (MBHF) approach to the single-particle energies in nuclear matter, employing three recent versions of the Bonn meson-exchange potential model. The non-relativistic MBHF calculations form the well known ''Coester'' band, where the potential which exhibits the weakest tensor force yields the largest binding energy per nucleon. Correcting for relativistic effects, the MBHF calculations result in too little binding. The implications are discussed. 12 refs., 2 figs

1992-01-01

369

Landau-Pomeranchuck-Migdal effect for nuclear matter in QCD

International Nuclear Information System (INIS)

Soft photon and gluon radiation off a fast quark propagating through nuclear matter is discussed. The close analogy between the Landau-Pomeranchuk - Migdal (LPM) effect in QED and the emission of soft gluons, suggested in ref. [1] for hot plasma, is confirmed and the relation between Mueller's approach and traditional calculations is established. It is shown that perturbative QCD can be applied to take into account the LPM coherent suppression both and gluon induced radiation. The formulae for the photon and gluon radiation densities are presented. (author). 15 refs, 4 figs

1995-01-01

370

The formation and properties of hot and dense nuclear matter

Energy Technology Data Exchange (ETDEWEB)

With the Huygens vessel detectors, it becomes possible to study the reactions on an event by event basis and without introducing a priori constraints on the analysis by looking at only one exit channel. The new detection system is described and it has been tested at GANIL in september 1992. The system will be used in the next years to extend the research on the properties of excited nuclear matter. The first step in disentangling the mechanisms contributing to heavy ion reactions at intermediate energies is a study of flow proposed at the GANIL accelerator facility, Caen, France, and explained in this article.

Bootsma, T.M.V.; van den Brink, A.; Haas, A.P. de; Kamermans, R.; Kuijer, P.G.; Laat, C.T.A.M. de; van Nieuwenhuizen, G.J.; Ostendorf, R.W.; Snellings, R.J.M.; Twenhoefel, C.J.W. (Rijksuniversiteit Utrecht (Netherlands). Robert van de Graaff Lab.)

1992-12-01

371

Antineutrinos in nuclear matter-evidence for strings

Energy Technology Data Exchange (ETDEWEB)

The two experiments reported consisted of passing the same antineutrino wide band beam through BEBC, firstly, when it was filled with hydrogen, and secondly, when it was filled with a neon-hydrogen mix. The lab rapidity of negative hadrons produced in antineutrino-proton interactions is compared with that of negative hadrons produced in antineutrino-neon interactions, and their ratio is obtained. The result is that at low energies there is a very large depletion while at high energies there is almost no depletion. This suggests that at high energy the struck quark can pass through nuclear matter almost without interacting, supporting the string model. 5 refs., 3 figs. (LEW)

Morrison, D.R.O.

1983-10-12

372

Study of the ?(1116) interaction in cold nuclear matter

The interaction of ? hyperons with baryonic nuclear matter at saturation density is expected to be attractive. The interaction strength was extracted from hypernuclei data. A different approach to obtain the potential depth of the ? mean-field potential is to compare experimental data with transport simulations. We analyze experimental data of ? hyperons measured with the HADES detector in p+93Nb reactions with a kinetic beam energy of 3.5 GeV carried by the proton. The high statistic of measured ? hyperons allows us to perform a double differential analysis in Lorentz-invariant observables of transverse momentum and rapidity. We present the analysis method and a comparison with simulations.

Arnold, Oliver

2014-03-01

373

Quark mean field theory and consistency with nuclear matter

International Nuclear Information System (INIS)

1/N_c expansion in QCD (with N_c the number of colours) suggests using a potential from meson sector (e.g. Richardson) for baryons. For light quarks a ? field has to be introduced to ensure chiral symmetry breaking (_?SB). It is found that nuclear matter properties can be used to pin down the _?SB-modelling. All masses, M_N, m_?, m_? are found to scale with density. The equations are solved self consistently. (author). 29 refs, 2 tabs

1990-01-01

374

Transport coefficients of nuclear matter in neutron star cores

We calculate thermal conductivity and shear viscosity of nucleons in the dense nuclear matter of neutron star cores in the nonrelativistic Brueckner-Hartree-Fock framework. The nucleon-nucleon interaction is described by the Argonne v18 potential with addition of the Urbana IX effective three-body forces. We find that this three-body force leads to a decrease of the kinetic coefficients with respect to the two-body case. The results of calculations are compared with electron and muon transport coefficients as well as with the results of other authors.

Shternin, P. S.; Baldo, M.; Haensel, P.

2013-12-01

375

Pion production as a test of nuclear matter properties

Energy Technology Data Exchange (ETDEWEB)

Nuclear matter equations of state are constructed which incorporate explicitly the pion and delta degrees of freedom. These are used in relativistic one-dimensional and three-dimensional hydrodynamical models of central nucleus-nucleus collisions to determine the influence of the compressional energy on the observed pion multiplicity. We find a modest dependence on the compressional energy but a significant difference between slab-slab and sphere-sphere collisions having to do with curved shock waves. Thus one-dimensional hydrodynamic models do not appear to be suitable for interpreting pion production at energies of 100 MeV-2 GeV.

Clare, R.B.; Strottman, D.; Kapusta, J.

1986-04-01

376

Transport coefficients of nuclear matter in neutron star cores

We calculate thermal conductivity and shear viscosity of nucleons in dense nuclear matter of neutron star cores in the non-relativistic Brueckner-Hartree-Fock framework. Nucleon-nucleon interaction is described by the Argonne v18 potential with addition of the Urbana IX effective three-body forces. We find that this three body force leads to decrease of the kinetic coefficients with respect to the two-body case. The results of calculations are compared with electron and muon transport coefficients as well as with the results of other authors.

Shternin, P S; Haensel, P

2013-01-01

377

High-density nuclear matter with nonlocal confining solitons

International Nuclear Information System (INIS)

An infinite system of nonlocal, individually confining solitons is considered as a model of high-density nuclear matter. The soliton-lattice problem is discussed in the Wigner-Seitz approximation. The cell size is varied to study the density dependence of physical quantities of interest. A transition to a system where quarks can migrate between solitons is found. We argue that this signals quark deconfinement. The model is applied to the calculation of selected in-medium properties. copyright 1997 The American Physical Society

1997-12-01

378

High-density nuclear matter with nonlocal confining solitons

Energy Technology Data Exchange (ETDEWEB)

An infinite system of nonlocal, individually confining solitons is considered as a model of high-density nuclear matter. The soliton-lattice problem is discussed in the Wigner-Seitz approximation. The cell size is varied to study the density dependence of physical quantities of interest. A transition to a system where quarks can migrate between solitons is found. We argue that this signals quark deconfinement. The model is applied to the calculation of selected in-medium properties. {copyright} {ital 1997} {ital The American Physical Society}

Johnson, C.W.; Fai, G. [Center for Nuclear Research, Department of Physics, Kent State University, Kent, Ohio 44242 (United States)

1997-12-01

379

Exponential enhancement of nuclear reactions in condensed matter environment

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 energy and momentum of the projectile in several ``preliminary'' elastic collisions with the target nucleus and the environmental nuclei in such a way that the final inelastic projectile-target collision takes place at a larger relative velocity, which is accompanied by a decrease of the center of mass energy. The gain of the relative velocity exponentially increases the penetration through the Coulomb barrier.

Kuchiev, M Yu; Flambaum, V V

2003-01-01

380

QCD sum rules for ? isobar in nuclear matter

International Nuclear Information System (INIS)

The self-energies of ? isobars propagating in nuclear matter are calculated using the finite-density QCD sum-rule methods. The calculations show that the Lorentz vector self-energy for the ? is significantly smaller than the nucleon vector self-energy. The magnitude of the ? scalar self-energy is larger than the corresponding value for the nucleon, which suggests a strong attractive net self-energy for the ?; however, the prediction for the scalar self-energy is very sensitive to the density dependence of certain in-medium four-quark condensate. Phenomenological implications for the couplings of the ? to the nuclear scalar and vector fields are briefly discussed

1995-04-01

381

QCD sum rules for $\\Delta$ isobar in nuclear matter

The self-energies of \\Delta isobar propagating in nuclear matter are calculated using the finite-density QCD sum-rule methods. The calculations show that the Lorentz vector self-energy for the \\Delta is significantly smaller than the nucleon vector self-energy. The magnitude of the \\Delta scalar self-energy is larger than the corresponding value for the nucleon, which suggests a strong attractive net self-energy for the \\Delta; however, the prediction for the scalar self-energy is very sensitive to the density dependence of certain in-medium four-quark condensate. Phenomenological implications for the couplings of the \\Delta to the nuclear scalar and vector fields are briefly discussed.

Jin, X

1994-01-01

382

Nuclear binding energy and symmetry energy of nuclear matter with modern nucleon-nucleon potentials

International Nuclear Information System (INIS)

Research highlights: ? The nuclear matter is studied within the Brueckner-Hartree-Fock (BHF) approach employing the most recent accurate nucleon-nucleon potentials. ? The results come out by approximating the single particle self-consistent potential with a parabolic form. ? We discuss the current status of the Coester line, i.e., density and energy of the various saturation points being strongly linearly correlated. ? The nuclear symmetry energy is calculated as the difference between the binding energy of pure neutron matter and that of symmetric nuclear matter. - Abstract: The binding energy of nuclear matter at zero temperature in the Brueckner-Hartree-Fock approximation with modern nucleon-nucleon potentials is studied. Both the standard and continuous choices of single particle energies are used. These modern nucleon-nucleon potentials fit the deuteron properties and are phase shifts equivalent. Comparison with other calculations is made. In addition we present results for the symmetry energy obtained with different potentials, which is of great importance in astrophysical calculation.

2011-03-01

383

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

1988-01-01

384

Chiral four-body interactions in nuclear matter

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...

Kaiser, N

2012-01-01

385

Non-Abelian energy loss in cold nuclear matter

International Nuclear Information System (INIS)

We use a formal recurrence relation approach to multiple parton scattering to find the complete solution to the problem of medium-induced gluon emission from partons propagating in cold nuclear matter. The differential bremsstrahlung spectrum, where Landau-Pomeranchuk-Migdal destructive interference effects are fully accounted for, is calculated for three different cases: (i) a generalization of the incoherent Bertsch-Gunion solution for asymptotic on-shell jets (ii) initial-state energy loss of incoming jets that undergo hard scattering, and (iii) final-state energy loss of jets that emerge out of a hard scatter. Our analytic solutions are given as an infinite opacity series, which represents a cluster expansion of the sequential multiple scattering. These new solutions allow, for the first time, direct comparison between initial- and final-state energy loss in cold nuclei. We demonstrate that, contrary to the naive assumption, energy loss in cold nuclear matter can be large. Numerical results to first order in opacity show that, in the limit of large jet energies, initial- and final-state energy losses exhibit different path length dependences, linear versus quadratic, in contrast to earlier findings. In addition, in this asymptotic limit, initial-state energy loss is considerably larger than final-state energy loss. These new results have significant implications for heavy-ion phenomenology in both p+A and A+A reactions

2007-06-01

386

Two-, three- and four-body correlations in nuclear matter

International Nuclear Information System (INIS)

Contributions of the two-, three- and four-body correlations to the binding energy of nuclear matter are calculated for potentials with soft-core. The potentials are composed of both attractive and repulsive parts. The potentials used are of the Yamaguchi, Gaussian and Tabakin forms. The single-particle potentials are considered to vanish for states above the Fermi sea. At kF = 1.35 fm-1, the potentials give a binding energy of 7.92-9.97 MeV from two-body correlations. An extra binding energy from three-body correlations is provided with values of 2.49-3.08 MeV. Four-body correlations add more binding energy of 0.71-1.13 MeV. Thus, the total contribution to the binding energy of nuclear matter from two-, three- and four-body correlations, using these potentials and at kF = 1.35 fm-1 is 11.12-14.18 MeV which is not far from the empirical value of 16 MeV. 28 refs., 2 tables. (author)

1986-01-01

387

Pure Neutron Matter Constraints and Nuclear Symmetry Energy

In this review, we will discuss the results of our recent work to study the general optimization of the pure isovector parameters of the popular relativistic mean-field (RMF) and Skyrme-Hartree-Fock (SHF) nuclear energy-density functionals (EDFs), using constraints on the pure neutron matter (PNM) equation of state (EoS) from recent {\\sl ab initio} calculations. By using RMF and SHF parameterizations that give equivalent predictions for ground-state properties of doubly magic nuclei and properties of symmetric nuclear matter (SNM) and PNM, we found that such optimization leads to broadly consistent symmetry energy $J$ and its slope parameter $L$ at saturation density within a tight range of $\\sigma(J) < 2$ MeV and $\\sigma(L) < 6$ MeV. We demonstrate that a clear model dependence shows up (a) in the curvature parameter of the symmetry energy $K_{\\rm sym}$, (b) the symmetry energy at supra-saturation densities, and (c) the radius of neutron stars.

Fattoyev, F J; Xu, Jun; Li, Bao-An

2012-01-01

388

J/psi production in proton-nucleus collisions at ALICE: cold nuclear matter really matters

Heavy quarkonia are expected to be sensitive to the properties of strongly interacting matter, at both low and high temperatures. In nucleus-nucleus collisions, a phase transition to a deconfined state of quarks and gluons (Quark-Gluon Plasma) is thought to take place once the temperature of the system exceeds a critical temperature of the order of 150-200 MeV. The deconfined state can induce a suppression of charmonium (due to color screening, dominant at SPS and RHIC energies), which can be overturned at LHC energy by the (re)combination of the large number of free c and cbar quarks, taking place when the system cools down below the critical temperature. Cold nuclear matter also has an influence on heavy quarkonia. Such effects can be studied in proton-nucleus collisions, where no deconfined state is expected to be created. At LHC energy, they mainly include nuclear shadowing, gluon saturation, break-up of the quarkonium states, and parton energy loss in the initial and final state. The study of these eff...

CERN. Geneva

2013-01-01

389

International Nuclear Information System (INIS)

We explore the abundance of light clusters in asymmetric nuclear matter at subsaturation density. With increasing density, binding energies and wave functions are modified due to medium effects. The method of Albergo, Costa, Costanzo, and Rubbino (ACCR) for determining the temperature and free nucleon density of a disassembling hot nuclear source from fragment yields is modified to include, in addition to Coulomb effects and flow, also effects of medium modifications of cluster properties, which become of importance when the nuclear matter density is above 10-3 fm-3. We show how the analysis of cluster yields, to infer temperature and nucleon densities, is modified if the shifts in binding energies of in medium clusters are included. Although, at low densities, the temperature calculated from given yields changes only modestly if medium effects are taken into account, larger discrepancies are observed when the nucleon densities are determined from measured yields

2009-03-01

390

Chiral condensate in neutron matter

Digital Repository Infrastructure Vision for European Research (DRIVER)

A recent chiral perturbation theory calculation of the in-medium quark condensate $$ is extended to the isospin-asymmetric case of pure neutron matter. In contrast to the behavior in isospin-symmetric nuclear matter we find only small deviations from the linear density approximation. This feature originates primarily from the reduced weight factors (e.g. 1/6 for the dominant contributions) of the $2\\pi$-exchange mechanisms in pure neutron matter. Our result suggest...

Kaiser, N.; Weise, W.

2008-01-01

391

Effect of nuclear response functions in dark matter direct detection

We examine the effect of nuclear response functions, as laid out by Fitzpatrick et al. [J. Cosmol. Astropart. Phys. 02 (2013) 004], on dark matter (DM) direct detection in the context of well-motivated UV completions, including electric and magnetic dipoles, anapole, spin-orbit, and pseudoscalar-mediated DM. Together, these encompass five of the six nuclear responses extracted from the nonrelativistic effective theory of Fitzpatrick et al. [J. Cosmol. Astropart. Phys. 02 (2013) 004] (with the sixth difficult to UV complete), with two of the six combinations corresponding to standard spin-independent and spin-dependent responses. For constraints from existing direct detection experiments, we find that only the COUPP constraint, due to its heavy iodine target with large angular momentum and an unpaired spin, and its large energy range sensitivity, is substantially modified by the new responses compared to what would be inferred using the standard form factors to model the energy dependence of the response. For heavy targets such as xenon and germanium, the behavior of the new nuclear responses as recoil energy increases can be substantially different from that of the standard responses, but this has almost no impact on the constraints derived from experiments such as LUX, XENON100, and CDMS since the maximum nuclear recoil energy detected in these experiments is relatively low. We simulate mock data for 80 and 250 GeV DM candidates utilizing the new nuclear responses to highlight how they might affect a putative signal, and find the new responses are most important for highly momentum-suppressed interactions such as the magnetic dipole or pseudoscalar-mediated interaction when the target is relatively heavy (such as xenon and iodine).

Gresham, Moira I.; Zurek, Kathryn M.

2014-06-01

392

Nuclear fusion in dense matter: Reaction rate and carbon burning

In this paper we analyze the nuclear fusion rate between equal nuclei for all five different nuclear burning regimes in dense matter (two thermonuclear regimes, two pycnonuclear ones, and the intermediate regime). The rate is determined by Coulomb barrier penetration in dense environments and by the astrophysical S-factor at low energies. We evaluate previous studies of the Coulomb barrier problem and propose a simple phenomenological formula for the reaction rate which covers all cases. The parameters of this formula can be varied, taking into account current theoretical uncertainties in the reaction rate. The results are illustrated for the example of the ^{12}C+^{12}C fusion reaction. This reaction is very important for the understanding of nuclear burning in evolved stars, in exploding white dwarfs producing type Ia supernovae, and in accreting neutron stars. The S-factor at stellar energies depends on a reliable fit and extrapolation of the experimental data. We calculate the energy dependence of the S-f...

Gasques, L R; Aguilera, E F; Beard, M; Chamon, L C; Ring, P; Wiescher, M; Yakovlev, D G

2005-01-01

393

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

2003-08-19

394

Quantum Vacuum in Hot Nuclear Matter A Nonperturbative Treatment

We derive the equation of state for hot nuclear matter using Walecka model in a nonperturbative formalism. We include here the vacuum polarisation effects arising from the nucleon and scalar mesons through a realignment of the vacuum. A ground state structure with baryon-antibaryon condensates yields the results obtained through the relativistic Hartree approximation (RHA) of summing baryonic tadpole diagrams. Generalization of such a state to include the quantum effects for the scalar meson fields through the $\\sigma$-meson condensates amounts to summing over a class of multiloop diagrams. The techniques of thermofield dynamics (TFD) method are used for the finite temperature and finite density calculations. The in-medium nucleon and sigma meson masses are also calculated in a self consistent manner. We examine the liquid-gas phase transition at low temperatures ($\\approx$ 20 MeV), as well as apply the formalism to high temperatures to examine for a possible chiral symmetry restoration phase transition.

Mishra, A K; Greiner, W; Mishra, Amruta

2001-01-01

395

The ground state of nuclear matter with virtual ?-isobar excitations

International Nuclear Information System (INIS)

The equation of state of nuclear matter is studied in the framework of the Bethe-Brueckner-Goldstone theory using the local Argonne v28 potential which explicitly includes ?-isobar degrees of freedom. The self-consistent two-body reaction matrix is obtained with all possible allowed couplings to the N? and ?? states. Saturation occurs around kF=1.2 fm-1 with a binding energy per particle B/A=-10.31 MeV, confirming the effect of the isobar in pushing the saturation point to the upper side of the Coester band. The present results are very close to the ones obtained in full coupled-channel relativistic calculations. (orig.)

1991-11-04

396

The ground state of nuclear matter with virtual ?-isobar excitations

The equation of state of nuclear matter is studied in the framework of the Bethe-Brueckner-Goldstone theory using the local Argonne v28 potential which explicitly includes ?-isobar degrees of freedom. The self-consistent two-body reaction matrix is obtained with all possible allowed couplings to the N? and ?? states. Saturation occurs around kF=1.2 fm -1 with a binding energy per particle {B}/{A}=-10.31 MeV, confirming the effect of the isobar in pushing the saturation point to the upper side of the Coester band. The present results are very close to the ones obtained in full coupled-channel relativistic calculations.

Baldo, M.; Ferreira, L. S.

1991-11-01

397

Study of the ?(1116 interaction in cold nuclear matter

Directory of Open Access Journals (Sweden)

Full Text Available The interaction of ? hyperons with baryonic nuclear matter at saturation density is expected to be attractive. The interaction strength was extracted from hypernuclei data. A different approach to obtain the potential depth of the ? mean-field potential is to compare experimental data with transport simulations. We analyze experimental data of ? hyperons measured with the HADES detector in p+93Nb reactions with a kinetic beam energy of 3.5 GeV carried by the proton. The high statistic of measured ? hyperons allows us to perform a double differential analysis in Lorentz-invariant observables of transverse momentum and rapidity. We present the analysis method and a comparison with simulations.

Arnold Oliver

2014-03-01

398

Dynamics of hot and dense nuclear and partonic matter

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.

Bratkovskaya, E. L.; Cassing, W.; Linnyk, O.; Konchakovski, V. P.; Voronyuk, V.; Ozvenchuk, V.

2012-06-01

399

Directory of Open Access Journals (Sweden)

Full Text Available One of the most interesting application of the many-body methods to the nuclear physics is the calculation of the properties of the nuclear matter, especially its binding energy. In this paper, we have studied the influence of ? -isobar on the properties of the symmetrical nuclear matter using the lowest order constrained variational (LOCV method with the V28 potential. It is shown that the inclusion of ?- isobar substantially affect the saturation properties of the symmetrical nuclear matter. We have shown that, at low (high densities, the saturation curve of nuclear matter is shifted downward (upward. This is due to the fact that the repulsive effect of the V28 potential increases by increasing density. It is seen that the equation of state of nuclear matter with the V28 potential is much harder than those with the A V14 potential.

G. H. Bordbar

2001-12-01

400

Neutrino mean free paths in cold symmetric nuclear matter

The neutrino mean free paths (NMFP) for scattering and absorption in cold symmetric nuclear matter (SNM) are calculated using two-body effective interactions and one-body effective weak operators obtained from realistic models of nuclear forces using correlated basis theory. The infinite system is modeled in a box with periodic boundary conditions and the one particle-hole ( p-h ) response functions are calculated using the Tamm-Dancoff approximation (TDA). For the densities ?= 1 /2 , 1, 3 /2 ?0 , where ?0 is the equilibrium density of SNM, the strength of the response is shifted to higher energy transfers when compared to a noninteracting Fermi gas (FG). This and the weakness of effective operators compared to the bare operators, significantly reduces the cross sections, enhancing the NMFP by factors of ˜2.5 3.5 at the densities considered. The NMFP at the equilibrium density ?0 are also calculated using the TDA and random phase approximation (RPA) using zero range Skyrme-like effective interactions with parameters chosen to reproduce the equation of state and spin-isospin susceptibilities of matter. Their results indicate that RPA corrections to correlated TDA may further increase the NMFP by ˜25% to 3 4 times those in a noninteracting FG. Finally, the sums and the energy weighted sums of the Fermi and Gamow-Teller responses obtained from the correlated ground state are compared with those of the 1 p-h response functions to extract the sum and mean energies of multi p-h contributions to the weak response. The relatively large mean energy of the multi p-h excitations suggests that they may not contribute significantly to low energy NMFP.

Cowell, S.; Pandharipande, V. R.

2004-09-01

401

Neutrino mean free paths in cold symmetric nuclear matter

International Nuclear Information System (INIS)

The neutrino mean free paths (NMFP) for scattering and absorption in cold symmetric nuclear matter (SNM) are calculated using two-body effective interactions and one-body effective weak operators obtained from realistic models of nuclear forces using correlated basis theory. The infinite system is modeled in a box with periodic boundary conditions and the one particle-hole (p-h) response functions are calculated using the Tamm-Dancoff approximation (TDA). For the densities ?=(1/2), 1 (3/2)?0, where ?0 is the equilibrium density of SNM, the strength of the response is shifted to higher energy transfers when compared to a noninteracting Fermi gas (FG). This and the weakness of effective operators compared to the bare operators, significantly reduces the cross sections, enhancing the NMFP by factors of ?2.5-3.5 at the densities considered. The NMFP at the equilibrium density ?0 are also calculated using the TDA and random phase approximation (RPA) using zero range Skyrme-like effective interactions with parameters chosen to reproduce the equation of state and spin-isospin susceptibilities of matter. Their results indicate that RPA corrections to correlated TDA may further increase the NMFP by ?25% to 3-4 times those in a noninteracting FG. Finally, the sums and the energy weighted sums of the Fermi and Gamow-Teller responses obtained from the correlated ground state are compared with those of the 1 p-h response functions to extract the sum and mean energies of multi p-h contributions to the weak response. The relatively large mean energy of the multi p-h excitations suggests that they may not contribute significantly to low energy NMFP

2004-09-01

402

Short-range correlations in quark and nuclear matter

Energy Technology Data Exchange (ETDEWEB)

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.)

Froemel, Frank

2007-06-15

403

Interacting neutrino gas in a dense nuclear matter

International Nuclear Information System (INIS)

Full text: Relativistic mean field models have become an standard approach to describe nuclear matter at different density regimes. The model Lagrangian density where nucleons interact through the exchange of scalar, vector and isovector mesons has been widely used for that purpose. Here, our interest is turned to the behavior of the neutrinos inside the hadronic matter, composed by the nucleons and mesons. In particular, we want to investigate the effect of the weak force on the neutrino distribution in that system. So we add to the model Lagrangian the neutral Z boson and its interaction with nucleons and the neutrinos in the same spirit of the mean field approach, usually invoked to solve the model. We show that this procedure do not alter the hadronic distribution, as expected, but can have a large contribution to the description of the neutrino distribution and its mean free path. Effects of a nonzero temperature are also considered in our investigation. The inclusion of the charged weak bosons can be easily incorporated in our results, which, together with the addition of electrons with the constraint of neutral total charge, can make a possible realistic model to study neutron-rich stars. As a promising application, we intend to solve the relativistic TOV equation for the star, within and without the weak interaction in the model. (author)

2011-06-05

404

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)

2004-01-01

405

The first results of a new three-dimensional, finite temperature Skyrme-Hartree-Fock+BCS study of the properties of inhomogeneous nuclear matter at densities and temperatures leading to the transition to uniform nuclear matter are presented. A constraint is placed on the two independent components of the quadrupole moment in order to self-consistently explore the shape phase space of nuclear configurations. The scheme employed naturally allows effects such as (i) neutron drip, which results in an external neutron gas, (ii) the variety of exotic nuclear shapes expected for extremely neutron heavy nuclei, and (iii) the subsequent dissolution of these nuclei into nuclear matter. In this way, the equation of state can be calculated across phase transitions from lower densities (where one dimensional Hartree-Fock suffices) through to uniform nuclear matter without recourse to interpolation techniques between density regimes described by different physical models.

Newton, W G

2009-01-01

406

International Nuclear Information System (INIS)

The first results of a new three-dimensional, finite temperature Skyrme-Hartree-Fock+BCS study of the properties of inhomogeneous nuclear matter at densities and temperatures leading to the transition to uniform nuclear matter are presented. A constraint is placed on the two independent components of the quadrupole moment in order to self-consistently explore the shape phase space of nuclear configurations. The scheme employed naturally allows effects such as (i) neutron drip, which results in an external neutron gas, (ii) the variety of exotic nuclear shapes expected for extremely neutron heavy nuclei, and (iii) the subsequent dissolution of these nuclei into nuclear matter. In this way, the equation of state can be calculated across phase transitions from lower densities (where one dimensional Hartree-Fock suffices) through to uniform nuclear matter without recourse to interpolation techniques between density regimes described by different physical models.

2009-05-07

407

Nucleon mean free path in nuclear matter based on nuclear Schwinger-Dyson formalism

Digital Repository Infrastructure Vision for European Research (DRIVER)

A mean free path of nucleon moving through nuclear matter with kinetic energy of more than 100MeV is formulated based on the bare vertex nuclear Schwinger-Dyson (BNSD) method in the Walecka model. The self-energy which is derived from the higher order diagrams more than the forth order includes the Feynman part of propagator of energetic nucleon and grows up rapidly as an increase of kinetic energy. To avoid too large growth of these diagrams, meson propagators are modified ...

Mitsumori, Tomohiro; Noda, Nobuo; Koide, Kazuharu; Kouno, Hiroaki; Hasegawa, Akira; Nakano, Masahiro

1995-01-01

408

Directory of Open Access Journals (Sweden)

Full Text Available We review on a novel chiral power counting scheme for in-medium chiral perturbation theory with nucleons and pions as degrees of freedom. It allows for a systematic expansion taking into account local as well as pion-mediated inter-nucleon interactions. Based on this power counting, one can identify classes of nonperturbative diagrams that require a resummation. As a method for performing those resummations we review on the techniques of Unitary Chiral Pertubation Theory for nucleon-nucleon interactions. We then apply both power counting and non-perturbative methods to the example of calculating the pion self-energy in asymmetric nuclear matter up-to-and-including next-to-leading order. It is shown that the leading corrections involving in-medium nucleon-nucleon interactions cancel between each other at given chiral orders.

Oller J.A.

2010-04-01

409

Mean free path and the absorptive potential of a ? particle in nuclear matter

International Nuclear Information System (INIS)

It is shown that a proper treatment of the momentum dependence of the real part of the ? optical potential in nuclear matter leads to a significant increase in the calculated ? mean free path, and to a corresponding decrease in the depth of the imaginary part of an equivalent local optical potential of ? in nuclear matter. (orig.)

1984-05-03

410

Search for phase transition in nuclear matter for temperatures up to 7 MeV

Energy Technology Data Exchange (ETDEWEB)

The {sup 208}Pb+{sup 197}Au system is investigated in order to search for phase transformation in the nuclear matter. No evidence can be found in our data for a phase transition in nuclear matter for temperatures up to 7 MeV. (K.A.). 8 refs.

Morjean, M.; Chbihi, A.; Galin, J.; Guerreau, D. [Grand Accelerateur National d`Ions Lourds (GANIL), 14 - Caen (France); Lebrun, C.; Ardouin, D.; Dabrowski, H.; Erazmus, B.; Eudes, P.; Guilbault, F. [Centre National de la Recherche Scientifique, 44 - Nantes (France). Lab. de Physique Subatomique et des Technologies Associees; and others

1996-09-01

411

Investigation of nuclear matter properties by means of high energy nucleus-nucleus collisions

International Nuclear Information System (INIS)

We review recent advances towards an understanding of high density nuclear matter, as created in central collisions of nuclei at high energy. In particular, information obtained for the nuclear matter equation of state will be discussed. The lectures focus on the Bevalac energy domain of 0.4 to 2 GeV per projectile nucleon. (orig.)

1985-04-10

412

Deuterization and the Mott density in nuclear matter at finite temperature

International Nuclear Information System (INIS)

The theory of thermodynamic properties of nuclear matter at finite temperatures is formulated on the base of thermodynamic Green functions for a system of interacting nucleons. The influence of the surrounding matter on the two-nucleon system leads to attenuation of the effective nucleon-nucleon interaction, and near the Mott density which depends on the temperature as well as on the total momentum of the two-nucleon system the bound state vanishes. The association degree of deuterons and the phase diagram of nuclear matter is considered. The purpose of the present paper is to study the problem on two nucleons being under the influence of the surrounding nuclear matter

1982-09-01

413

PION CONDENSATION IN A RELATIVISTIC FIELD THEORY CONSISTENT WITH BULK PROPERTIES OF NUCLEAR MATTER

Energy Technology Data Exchange (ETDEWEB)

Pion condensation has not previously been investigated in a theory that accounts for the known bulk properties of nuclear matter, its saturation energy and density and compressibility. We have formulated and solved self-consistently, in the mean field approximation, a relativistic field theory that possesses a condensate solution and reproduces the correct bulk properties of nuclear matter, The theory is solved in its relativistically covariant form for a general class of space-time dependent pion condensates. Self-consistency and compatibility with bulk properties of nuclear matter turn out to be very stringent conditions on the existence and energy of the condensate, but they do allow a weak condensate energy to develop. The spin-isospin density oscillations, on the other hand, can be large. It is encouraging, as concerns the possible existence of new phases of nuclear matter, that this is so, unlike the Lee-Wick density isomer, that appears to be incompatible with nuclear matter properties.

Banerjee, B.; Glendenning, N.K.; Gyulassy, M.

1980-07-01

414

Particle clustering and Mott transitions in nuclear matter at finite temperature. Pt. 1

International Nuclear Information System (INIS)

The thermodynamic state of nuclear matter as regards dependence on density and temperature is considered. Expressions for the association degree are derived describing the ratio of nuclear matter which is clustered to bound states. The problem of two nucleons imbedded in the surrounding nuclear matter is considered with the help of the Bethe-Goldstone equation for thermodynamic Green functions. The two-particle energy shift due to the effective nuclear matter hamiltonian is considered in a Hartree-Fock approximation, and a Mott density is obtained so that for densities of nuclear matter higher than the Mott density bound states cannot exist. With a simplified effective two-nucleon interaction the association degree is calculated as a function of the nucleon density and the temperature. (orig.)

1982-05-10

415

Clusterized nuclear matter in the (proto-)neutron star crust and the symmetry energy

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

Raduta, Ad R.; Aymard, F.; Gulminelli, F.

2013-01-01

416

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.)

1987-01-01

417

The effect of elastic properties of nuclear matter on nuclear fission

Energy Technology Data Exchange (ETDEWEB)

Spheroidal nuclear vibrations are considered using a macroscopic model based on the assumption that nuclear matter possesses the properties of elastic medium. Emphasis is laid on the analysis of instability of the quadrupole configuration. It is presumed that the onset of this instability is associated with the commencement of fission. The proposed fluid-dynamics model predicts the values of the parameters of nuclear fission that differ somewhat from the values given by the standard liquid drop-model. In particular, the obtained critical ratio Z{sup 2}/A, which characterizes the loss of stability of the quadrupole mode, is equal to 35. It follows from this estimate that fission induced by an external perturbation should be expected for nuclei (from the {beta}-stability valley) with A{>=}230. 16 refs.

Bastrukov, S.I.; Molodtsova, I.V.; Yuldashbaeva, E.Kh. [Joint Institute for Nuclear Research, Moscow (Russian Federation)

1994-07-01

418

The present theses present for the case of the Walecka model a first attempt to describe nuclear and neutron matter beyond the thermal equilibrium in the framework of a relativistic quantum field theory. Nuclear matter with two oppositely directed nucleon...

M. Cubero del Castillo-Olivares M. Schoenhofen

1986-01-01

419

Half-Skyrmions and the Equation of State for Compact-Star Matter

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Dong, Huan; Kuo, T. T. S.; Lee, Hyun Kyu; Machleidt, R.; Rho, Mannque

2012-01-01

420

Neutron-Proton Mass Difference in Nuclear Matter and in Finite Nuclei and the Nolen-Schiffer Anomaly

Directory of Open Access Journals (Sweden)

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.

Yakhshiev U.T.

2010-04-01

421

Functional renormalization group approach to neutron matter

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.

Drews, Matthias

2014-01-01

422

Compression and speed of sound in nuclear matter

International Nuclear Information System (INIS)

It is shown how important is the choice of an equation of state and especially its compression modulus in the infinite symmetric nuclear matter. It is also exhibited the effect of the thermal energy determined here by the non relativistic Rankine-Hugoniot equation. All the calculations performed with a zero thermal energy give a speed of sound which overpass c at high density; when this thermal energy is taken into account this behaviour is conserved for the interactions giving a too high K value. However such a conclusion about this effect must be moderated since it is shown that it appears at very high densities. Such densities seem too high to be reached, the dispersive effects becoming very important when the incident energy increases. It is also obvious that a convenient equation of state at high density must take into account many other effects like hadronic resonances and pion production. To perform some calculations with a relativistic Rankine-Hugoniot equation it is used an equation of state which includes relativistic effects. Attention is also focused about a general treatment at finite temperature of this problem derived from the Hartree-Fock calculations at finite temperature

1979-01-01

423

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

1997-03-01

424

Brueckner G matrix for a planar slab of nuclear matter

International Nuclear Information System (INIS)

The equation for the Brueckner G matrix is investigated for planar-slab geometry. A method for calculating the G matrix for a planar slab of nuclear matter is developed for a separable form of NN interaction. Actually, the separable version of the Paris NN potential is used. The singlet 1S0 and the triplet 3S1-3D1 channel are considered. The present analysis relies on the mixed momentum-coordinate representation, where use is made of the momentum representation in the slab plane and of the coordinate representation in the orthogonal direction. The full two-particle Hilbert space is broken down into the model subspace, where the two-particle propagator is considered exactly, and the complementary subspace, where the local-potential approximation is used, which was proposed previously for calculating the effective pairing potential. Specific calculations are performed for the case where the model subspace is constructed on the basis of negative-energy single-particle states. The G matrix is parametrically dependent on the total two-particle energy E and the total momentum Pperpendicular in the slab plane. Since the G matrix is assumed to be further used to calculate the Landau-Migdal amplitude, the total two-particle energy is fixed at the value E = 2?, where ? is the chemical potential of the system under investigation. The calculations are performed predominantly for Pperpendicular = 0. The role of nonzero values of Pperpendicular is assessed. The resulting G matrix is found to depend greatly on ? in the surface region

2001-02-01

425

Electron screening in the liquid-gas mixed phases of nuclear matter

Screening effects of electrons on inhomogeneous nuclear matter, which includes spherical, slablike, and rodlike nuclei as well as spherical and rodlike nuclear bubbles, are investigated in view of possible application to cold neutron star matter and supernova matter at subnuclear densities. Using a compressible liquid-drop model incorporating uncertainties in the surface tension, we find that the energy change due to the screening effects broadens the density region in which bubbles and nonspherical nuclei appear in the phase diagram delineating the energetically favorable shape of inhomogeneous nuclear matter. This conclusion is considered to be general since it stems from a model-independent feature that the electron screening acts to decrease the density at which spherical nuclei become unstable against fission and to increase the density at which uniform matter becomes unstable against proton clustering.

Watanabe, G; Watanabe, Gentaro; Iida, Kei

2003-01-01

426

Electron screening in the liquid-gas mixed phases of nuclear matter

International Nuclear Information System (INIS)

Screening effects of electrons on inhomogeneous nuclear matter, which includes spherical, slablike, and rodlike nuclei as well as spherical and rodlike nuclear bubbles, are investigated in view of possible application to cold neutron star matter and supernova matter at subnuclear densities. Using a compressible liquid-drop model incorporating uncertainties in the surface tension, we find that the energy change due to the screening effects broadens the density region in which bubbles and nonspherical nuclei appear in the phase diagram delineating the energetically favorable shape of inhomogeneous nuclear matter. This conclusion is considered to be general since it stems from a model-independent feature that the electron screening acts to decrease the density at which spherical nuclei become unstable against fission and to increase the density at which uniform matter becomes unstable against proton clustering

2003-10-01

427

Critical analysis of quark-meson coupling models for nuclear matter and finite nuclei

Three versions of the quark-meson coupling (QMC) model are applied to describe properties of nuclear matter and finite nuclei. The models differ in the treatment of the bag constant and in terms of nonlinear scalar self-interactions. As a consequence opposite predictions for the medium modifications of the internal nucleon structure arise. After calibrating the model parameters at equilibrium nuclear matter density, binding energies, charge radii, single-particle spectra and density distributions of spherical nuclei are analyzed and compared with QHD calculations. For the models which predict a decreasing size of the nucleon in the nuclear environment, unrealistic features of the nuclear shapes arise.

Müller, H; Mueller, Horst; Jennings, Byron K.

1998-01-01

428

Constraints on the equation of state of cold dense matter from nuclear physics and astrophysics

Directory of Open Access Journals (Sweden)

Full Text Available The Brussels-Montreal equations of state of cold dense nuclear matter that have been recently developed are tested against various constraints coming from both nuclear physics and astrophysics. The nuclear physics constraints include the analysis of nuclear flow and kaon production in heavy-ion collision experiments, as well as recent microscopic many-body calculations of infinite homogeneous neutron matter. Astrophysical observations, especially recent neutron-star mass measurements, provide valuable constraints on the high-density part of the equation of state that is not accessible in laboratory experiments.

Fantina A. F.

2014-03-01

429

Pressure ensemble and dense nuclear matter with finite size nucleons at zero temperature

International Nuclear Information System (INIS)

The aim of this study is to find the equations of state of dense nuclear matter near the phase transition to quark-gluon-plasma. The effect of finite particle volume on the equation of state is calculated for both a hard sphere and a variable size particle Fermi gas using the pressure ensemble formalism in statistical physics and the MIT bag model. It is found that for high baryon densities only the variable volume description of the nuclear gas yields physically sensible results in that P/? < 1/3. The equations of state of nuclear matter at several times normal nuclear density show properties similar to those found by other methods

1986-07-08

430

What Do We Learn about Dense Nuclear Matter from Heavy-Ion Collision Experiments?

International Nuclear Information System (INIS)

Nucleus-nucleus collisions provide the unique opportunity to create and to investigate dense nuclear matter in the laboratory. The collision experiments address fundamental aspects of strong-interaction physics: the nuclear equation-of-state at high baryon densities, and the modification of hadron properties in the dense nuclear medium. The experimental results are relevant for our understanding of the dynamics of core-collapse supernovae, and of the structure of neutron stars. In particular, strange particles are promising diagnostic probes of dense nuclear matter. Existing experimental data, their theoretical interpretations, and future experiments will be discussed. (author)

2008-02-01

431

Dynamics of high energy heavy ion collisions - nuclear matter at high density and temperature

International Nuclear Information System (INIS)

Nuclear collisions at Esub(LAB) > 50 MeV/n are studied using the nuclear fluid dynamical and the cascade model. Evidence for the predicted compression effects has been found in recent experimental data: The preferential sidewards emission of light fragments as well as the azimuthal p-p correlations indicate the presence of collective flow phenomena. The analysis of future 4 ? exclusive experiments in terms of the kinetic flow tensor can yield information about the equation of state of the compressed nuclear matter. We also discuss the role of pions and strange particles as probes for the properties of nuclear matter at high excitation energy. (orig.)

1982-10-11

432

Specific viscosity of neutron-rich nuclear matter from a relaxation time approach

The specific viscosity of neutron-rich nuclear matter is studied from the relaxation time approach using an isospin- and momentum-dependent interaction and the nucleon-nucleon cross sections taken as those from the experimental data modified by the in-medium effective masses as used in the isospin-dependent Boltzmann-Uehling-Uhlenbeck (IBUU) transport model calculations. The relaxation time of neutrons is larger while that of protons is smaller in neutron-rich nuclear matter compared with that in symmetric nuclear matter, and this leads to a larger specific viscosity in neutron-rich nuclear matter. In addition, the specific viscosity decreases with increasing temperature because of more frequent collisions and weaker Pauli blocking effect at higher temperatures. At lower temperatures the specific viscosity increases with increasing density due to the Pauli blocking effect, while at higher temperatures it slightly decreases with increasing density as a result of smaller in-medium effective masses at higher densities.

Xu, Jun

2011-12-01

433

Analog of the Peierls-type phase transition in nuclear matter

International Nuclear Information System (INIS)

A phase transition of nuclear matter into a periodic phase has been found. Studying the properties of this phase transition an analogy has been observed with the Peierls' transition taking place in quasi-one-dimensional electric conductors. ((orig.))

1994-05-26

434

Quasiparticle interaction in nuclear matter with chiral three-nucleon forces

Digital Repository Infrastructure Vision for European Research (DRIVER)

We derive the effective interaction between two quasiparticles in symmetric nuclear matter resulting from the leading-order chiral three-nucleon force. We restrict our study to the L=0,1 Landau parameters of the central quasiparticle interaction computed to first order. We find that the three-nucleon force provides substantial repulsion in the isotropic spin- and isospin-independent component F_0 of the interaction. This repulsion acts to stabilize nuclear matter against iso...

Holt, J. W.; Kaiser, N.; Weise, W.

2011-01-01

435

Heated nuclear matter, condensation phenomena and the hadronic equation of state

The thermodynamic properties of heated nuclear matter are explored using an exactly solvable canonical ensemble model. This model reduces to the results of an ideal Fermi gas at low temperatures. At higher temperatures, the fragmentation of the nuclear matter into clusters of nucleons leads to features that resemble a Bose gas. Some parallels of this model with the phenomena of Bose condensation and with percolation phenomena are discussed. A simple expression for the hadronic equation of state is obtained from the model.

Chase, K C

1995-01-01

436

Digital Repository Infrastructure Vision for European Research (DRIVER)

[eng] The main contribution of this thesis concerns the application of the Luttinger-Ward formalism to the study of the thermodynamical properties of nuclear matter. This formalism is devoted to compute the different thermodynamical potentials from the Green's functions and therefore offers a consistent theoretical framework within which the microscopic as well as the macroscopic properties of nuclear matter can be treated at the same level. In this thesis, the Luttinger-Ward formalism has be...

Rios Huguet, Arnau

2007-01-01

437

Digital Repository Infrastructure Vision for European Research (DRIVER)

The main contribution of this thesis concerns the application of the Luttinger-Ward formalism to the study of the thermodynamical properties of nuclear matter. This formalism is devoted to compute the different thermodynamical potentials from the Green's functions and therefore offers a consistent theoretical framework within which the microscopic as well as the macroscopic properties of nuclear matter can be treated at the same level.In this thesis, the Luttinger-Ward formalism has been appl...

Rios Huguet, Arnau

2007-01-01

438

The phase diagram of nuclear and quark matter at high baryon density

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 transition and the inhomogeneous meson condensation in nuclear matter with emphasis put on the relevance to quark matter. We commence the next part focused on quark matter with the bootstrap model and the Hagedorn temperature. Then we turn to properties associated with chiral symmetry and exposit theoretical descriptions of the chiral phase transition. There emerge some quark-matter counterparts of phenomena seen in nuclear matter such as the liquid-gas phase transition and the inhomogeneous structure of the chiral condensate. The third reg...

Fukushima, Kenji

2013-01-01

439

...NUCLEAR REGULATORY COMMISSION [Docket No. 72-1044...EA-13-132] In the Matter of Entergy Nuclear Generation Company Pilgrim Power Station...License (Effective Immediately) AGENCY: Nuclear Regulatory Commission. ACTION:...

2013-08-06