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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

Incompressibility of asymmetric nuclear matter  

CERN Document Server

The incompressibility $K_sat(\\delta)$ of isospin asymmetric nuclear matter at its saturation density. Our results show that in the expansion of $K_sat(\\delta)$ in powers of isospin asymmetry $\\delta$, i.e., $K_sat(\\delta )$=K_{0}+K_{sat,2}\\delta^{2}+K_{sat,4}\\delta^{4}+O(\\delta^{6})$, the magnitude of the 4th-order K_{sat,4} parameter is generally small. The 2nd-order K_{sat,2} parameter thus essentially characterizes the isospin dependence of the incompressibility of asymmetric nuclear matter at saturation density. Furthermore, the K_{sat,2} can be expressed as K_{sat,2}=K_{sym}-6L-J_{0}/{K_{0}L in terms of the slope parameter $L$ and the curvature parameter $K_{\\mathrm{sym}}$ of the symmetry energy and the third-order derivative parameter $J_0$ of the energy of symmetric nuclear matter at saturation density, and we find the higher order $J_0$ contribution to K_{sat,2} generally cannot be neglected. Also, we have found a linear correlation between K_{sym} and $L$ as well as between $J_{0}/K_{0}$ and $K_{0}$....

Chen, Lie-Wen; Shen, Chun; Ko, Che Ming; Xu, Jun; Li, Bao-An

2009-01-01

3

Quasideuteron pairing in asymmetric nuclear matter  

International Nuclear Information System (INIS)

We study the standard 1 S 0 and the quasideuteron 3 S 1-3 D 1 pairing fields in asymmetric nuclear matter, using a Bonn meson-exchange interaction in a Dirac-Hartree-Fock-Bogoliubov approximation. We obtain a quasideuteron field very similar to those found in nonrelativistic calculations at densities below saturation, both in symmetric and asymmetric nuclear matter. This field has the properties of a Bose-Einstein condensate at low densities and those of a BCS condensate at high densities. The quasideuteron pairing field in asymmetric nuclear matter is stable only when accompanied by standard 1 S 0 neutron-neutron and proton-proton pairing fields.

2007-06-15

4

Quasideuteron pairing in asymmetric nuclear matter  

Energy Technology Data Exchange (ETDEWEB)

We study the standard {sup 1} S {sub 0} and the quasideuteron {sup 3} S {sub 1}-{sup 3} D {sub 1} pairing fields in asymmetric nuclear matter, using a Bonn meson-exchange interaction in a Dirac-Hartree-Fock-Bogoliubov approximation. We obtain a quasideuteron field very similar to those found in nonrelativistic calculations at densities below saturation, both in symmetric and asymmetric nuclear matter. This field has the properties of a Bose-Einstein condensate at low densities and those of a BCS condensate at high densities. The quasideuteron pairing field in asymmetric nuclear matter is stable only when accompanied by standard {sup 1} S {sub 0} neutron-neutron and proton-proton pairing fields.

Funke Haas, B. [Depto. de Fisica, Instituto Tecnologico de Aeronautica, Praca Mal. Eduardo Gomes, 50, Sao Jose dos Campos SP (Brazil); Carlson, B.V. [Depto. de Fisica, Instituto Tecnologico de Aeronautica, Praca Mal. Eduardo Gomes, 50, Sao Jose dos Campos SP (Brazil); Frederico, Tobias [Depto. de Fisica, Instituto Tecnologico de Aeronautica, Praca Mal. Eduardo Gomes, 50, Sao Jose dos Campos SP (Brazil)

2007-06-15

5

Kaons and antikaons in asymmetric nuclear matter  

CERN Multimedia

The properties of kaons and antikaons and their modification in isospin asymmetric nuclear matter are investigated using a chiral SU(3) model. These isospin dependent medium effects are important for asymmetric heavy ion collision experiments. In the present work, the medium modifications of the energies of the kaons and antikaons, within the asymmetric nuclear matter, arise due to the interactions of kaons and antikaons with the nucleons and scalar mesons. The values of the parameters in the model are obtained by fitting the saturation properties of nuclear matter and kaon-nucleon scattering lengths. The pion-nucleon scattering lengths are also calculated within the chiral effective model and compared with earlier results from the literature. The density dependence of the isospin asymmetry is seen to be appreciable for the kaon and antikaon optical potentials. This can be particularly relevant for the future accelerator facility FAIR at GSI, where experiments using neutron rich beams are planned to be used i...

Mishra, A; Greiner, W

2008-01-01

6

Magnetic properties of strongly asymmetric nuclear matter  

International Nuclear Information System (INIS)

We investigate stability of neutron matter containing a small proton admixture with respect to spin fluctuations. We establish conditions under which strongly asymmetric nuclear matter could acquire a permanent magnetization. It is shown that if the protons are localized, the system becomes unstable to spin fluctuations for arbitrarily weak proton-neutron spin interactions. For non-localized protons there exists a threshold value of the spin interaction above which the system can develop a spontaneous polarization. 12 refs., 2 figs. (author)

1988-01-01

7

Isospin dependent properties of asymmetric nuclear matter  

CERN Multimedia

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

8

Asymmetric nuclear matter and its instabilities  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english In order to investigate the instabilities in asymmetric nuclear matter described within relativistic mean field hadron models, we build the spinodals. We have used relativistic models both with constant and density dependent couplings at zero and finite temperatures. We have seen that the main differences in the spinodals occur at finite temperature and large isospin asymmetry close to the boundary of the instability regions.

Avancini, S. S.; Menezes, D. P.; Brito, L.; Providência, C.

2005-09-01

9

Asymmetric nuclear matter equation of state  

Energy Technology Data Exchange (ETDEWEB)

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 {sup 3}{ital S}{sub 1-}{sup 3}{ital D}{sub 1} component of the {ital 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.

Bombaci, I.; Lombardo, U. (Dipartimento di Fisica, Universita di Catania, Corso Italia 57, Catania (Italy) Istituto Nazionale di Fisica Nucleare, Sezione di Catania, Corso Italia 57, I-95129 Catania (Italy))

1991-11-01

10

Symmetry energy coefficients for asymmetric nuclear matter  

Directory of Open Access Journals (Sweden)

Full Text Available Symmetry energy coefficients of asymmetric nuclear matter generalized are investigated as the inverse of nuclear matter polarizabilities with two different approaches. Firstly a general calculation shows they may depend on the neutron-proton asymmetry itself. The choice of particular prescriptions for the density fluctuations lead to certain isospin (n-p asymmetry) dependences of the polarizabilities. Secondly, with Skyrme type interactions, the static limit of the dynamical polarizability is investigated corresponding to the inverse symmetry energy coefficient which assumes different values at different asymmetries (and densities and temperatures). The symmetry energy coefficient (in the isovector channel) is found to increase as n-p asymmetries increase. The spin symmetry energy coefficient is also briefly investigated.

Braghin Fábio L.

2003-01-01

11

Pseudo-Goldstone modes in isospin-asymmetric nuclear matter  

International Nuclear Information System (INIS)

[en] The authors analyze the chiral limit in dense isospin-asymmetric nuclear matter. It is shown that the pseudo-Goldstone modes in this system are qualitatively different from the case of isospin-symmetric matter

1995-01-01

12

Pseudo-Goldstone modes in isospin-asymmetric nuclear matter  

Energy Technology Data Exchange (ETDEWEB)

The authors analyze the chiral limit in dense isospin-asymmetric nuclear matter. It is shown that the pseudo-Goldstone modes in this system are qualitatively different from the case of isospin-symmetric matter.

Cohen, T.D. [Univ. of Washington, Seattle, WA (United States); Broniowski, W. [H. Niewodniczanski Institute of Nuclear Physics, Cracow (Poland)

1995-01-01

13

Pseudo-Goldstone modes in isospin-asymmetric nuclear matter  

Energy Technology Data Exchange (ETDEWEB)

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.

Cohen, T.D. [Washington Univ., Seattle, WA (United States). Dept. of Physics; Broniowski, W. [Institute of Nuclear Physics, Cracow (Poland)

1994-12-01

14

EOS and Single Particle Properties of Asymmetric Nuclear Matter  

International Nuclear Information System (INIS)

[en] 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

15

Spin Polarized Asymmetrical Nuclear Matter and Neutron Star Matter Within the LOCV Method  

CERN Multimedia

In this paper, we calculate properties of the spin polarized asymmetrical nuclear matter and neutron star matter, using the lowest order constrained variational (LOCV) method with the $AV_{18}$, $Reid93$, $UV_{14}$ and $AV_{14}$ potentials. According to our results, the spontaneous phase transition to a ferromagnetic state in the asymmetrical nuclear matter as well as neutron star matter do not occur.

Bordbar, G H

2008-01-01

16

Calculation of the Structure Properties of Asymmetrical Nuclear Matter  

CERN Multimedia

In this paper the structure properties of asymmetrical nuclear matter has been calculated employing AV18 potential for different values of proton to neutron ratio. These calculations have been also made for the case of symmetrical nuclear matter with UV14, AV14 and AV18 potentials. In our calculations, we use the lowest order constrained variational (LOCV) method to compute the correlation function of the system.

Bordbar, G H

2011-01-01

17

Sum rules and correlations in asymmetric nuclear matter  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The neutron and proton single-particle spectral functions in asymmetric nuclear matter fulfill energy-weighted sum rules. The validity of these sum rules within the self-consistent Green's function approach is investigated. The various contributions to these sum rules and their convergence as a func...

Rios Huguet, Arnau; Polls Martí, Artur; Müther, Herbert

18

Spinodal decomposition of low-density asymmetric nuclear matter  

Energy Technology Data Exchange (ETDEWEB)

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.). 31 refs.

Baran, V. [Laboratorio Nazionale del Sud, Catania (Italy)]|[University of Catania, Catania (Italy)]|[Institutul de Fizica Atomica, Bucharest (Romania); Colonna, M.; Di Toro, M. [Laboratorio Nazionale del Sud, Catania (Italy)]|[University of Catania, Catania (Italy); Larionov, A.B. [Laboratorio Nazionale del Sud, Catania (Italy)]|[University of Catania, Catania (Italy)]|[RRC ``I.V. Kurchatov Institute``, Moscow 123182 (Russian Federation)

1998-03-16

19

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.

2006-01-01

20

Coulomb effects on growth of instabilities in asymmetric nuclear matter  

CERN Document Server

We study the effects of the Coulomb interaction on the growth of unstable modes in asymmetric nuclear matter. In order to compare with previous calculations we use a semiclassical approach based on the linearized Vlasov equation. Moreover, a quantum calculation is performed within the R.P.A.. The Coulomb effects are a slowing down of the growth and the occurrence of a minimal wave vector for the onset of the instabilities. The quantum corrections cause a further decrease of the growth rates.

Fabbri, G

1998-01-01

 
 
 
 
21

Collective modes and response functions of relativistic asymmetric nuclear matter  

Energy Technology Data Exchange (ETDEWEB)

Response functions and collective modes for asymmetric nuclear matter ([ital N][gt][ital Z]) are studied by means of a relativistic kinetic equation. Nuclear matter is described by means of a field theory of nucleons coupled to neutral, scalar ([sigma]), and vector ([omega]) mesons and to charged vector mesions ([rho]). The contribution of the exchange terms to the nucleon-nucleon interaction is also taken into account. Because of the exchange terms, the kinetic equation presents solutions which correspond to oscillations of the spin density. Finally the effects of an excess of neutrons on the response functions and on the collective modes are investigated. It is found that a collective oscillation present in symmetric nuclear matter disappears even for a small asymmetry ([similar to]5%).

Matera, F.; Denisov, V.Y. (Dipartimento di Fisica, Universita di Firenze, Firenze (Italy) Istituto Nazionale di Fisica Nucleare, Sezione di Firenze, Firenze (Italy))

1994-05-01

22

Onset of superfluidity in hot asymmetric nuclear matter  

International Nuclear Information System (INIS)

The onset of superfluidity in hot asymmetric nuclear matter is studied within a generalized Beth-Uhlenbeck approach. The finite tempeature t-matrix is of the Bethe-Goldstone type and contains hole-hole propagation not considered in the Brueckner G-matrix approach. It is shown that the phase contour for the onset of superfluidity in this approach is identical to that obtained within Gorkov's approach to BCS theory. Results for the realistic Paris potential imply that the critical temperature in the neutron-proton triplet channel is on the order of 6-8 MeV and thus much larger than that for singlet pairing. (orig.)

1991-01-01

23

A phenomenological equation of state for isospin asymmetric nuclear matter  

CERN Multimedia

A phenomenological momentum-independent (MID) model is constructed to describe the equation of state (EOS) for isospin asymmetric nuclear matter, especially the density dependence of the nuclear symmetry energy $E_{\\text{\\textrm{sym}}}(\\rho)$. This model can reasonably describe the general properties of the EOS for symmetric nuclear matter and the symmetry energy predicted by both the sophisticated isospin and momentum dependent MDI model and the Skyrme-Hartree-Fock approach. We find that there exists a nicely linear correlation between $K_{\\mathrm{sym}}$ and $L$ as well as between $J_{0}/K_{0} $ and $K_{0}$, where $L$ and $K_{\\mathrm{sym}}$ represent, respectively, the slope and curvature parameters of the symmetry energy at the normal nuclear density $\\rho_{0}$ while $K_{0}$ and $J_{0}$ are, respectively, the incompressibility and the third-order derivative parameter of symmetric nuclear matter at $\\rho_{0}$. These correlations together with the empirical constraints on $K_{0}$, $L$ and $E_{\\text{\\textrm{sy...

Chen, Lie-Wen

2009-01-01

24

Phases of asymmetric nuclear matter with broken space symmetries  

CERN Multimedia

Isoscalar Cooper pairing in isospin asymmetric nuclear matter occurs between states populating two distinct Fermi-surfaces, each for neutrons and protons. The transition from a BCS-like to the normal (unpaired) state, as the isospin asymmetry is increased, is intervened by superconducting phases which spontaneously break translational and rotational symmetries. One possibility is the formation of a condensate with a periodic crystalline-like structure where Cooper pairs carry net momentum (the nuclear LOFF-phase). Alternatively, perturbations of the Fermi-surfaces away from spherical symmetry allow for minima in the condensate free-energy which correspond to a states with quadrupole deformations of Fermi-surfaces and zero momentum of the Cooper pairs. In a combined treatment of these phases we show that, although the Cooper pairing with finite momentum might arise as a local minimum, the lowest energy state features deformed Fermi-surfaces and Cooper pairs with vanishing total momentum.

Müther, H

2003-01-01

25

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

26

Collective modes of asymmetric nuclear matter in quantum hadrodynamics  

International Nuclear Information System (INIS)

We discuss a fully relativistic Landau Fermi liquid theory based on the quantum hadrodynamics effective field picture of nuclear matter. From the linearized kinetic equations we get the dispersion relations of the propagating collective modes. We focus our attention on the dynamical effects of the interplay between scalar and vector channel contributions. An interesting 'mirror' structure in the form of the dynamical response in the isoscalar-isovector degree of freedom is revealed, with a complete parallelism in the role respectively played by the compressibility and the symmetry energy. All that seems to support the introduction of an explicit coupling to the scalar-isovector channel of the nucleon-nucleon interaction. In particular we study the influence of this coupling (to a ?-meson-like effective field) on the collective response of asymmetric nuclear matter (ANM). Interesting contributions are found on the propagation of isovectorlike modes at normal density and on an expected smooth transition to isoscalarlike oscillations at high baryon density. Important 'chemical' effects on the neutron-proton structure of the mode are shown. For dilute ANM we have the isospin distillation mechanism of the unstable isoscalarlike oscillations, while at high baryon density we predict an almost pure neutron wave structure of the propagating sounds.

2003-01-01

27

Finite temperature calculations for the spin polarized asymmetric nuclear matter with the LOCV method  

CERN Multimedia

The lowest order constrained variational (LOCV) technique has been used to investigate some of the thermodynamic properties of spin polarized hot asymmetric nuclear matter, such as the free energy, symmetry energy, susceptibility and equation of state. We have shown that the symmetry energy of the nuclear matter is substantially sensitive to the value of spin polarization. Our calculations show that the equation of state of the polarized hot asymmetric nuclear matter is stiffer for the higher values of the polarization as well as the isospin asymmetry parameter. Our results for the free energy and susceptibility show that the spontaneous ferromagnetic phase transition cannot occur for hot asymmetric matter.

Bigdeli, M; Poostforush, A

2010-01-01

28

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.

2010-01-01

29

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

CERN Multimedia

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

30

NUCLEAR AND HEAVY ION PHYSICS: Study of various charged ?-meson masses in asymmetric nuclear matter  

Science.gov (United States)

We study the effective masses of ?-mesons for different charged states in asymmetric nuclear matter (ANM) using the Quantum Hadrodynamics II model. The closed form analytical results are presented for the effective masses of ?-mesons. We have shown that the different charged ?-mesons have mass splitting similar to various charged pions. The effect of the Dirac sea is also examined, and it is found that this effect is very important and leads to a reduction of the different charged ?-meson masses in ANM.

Yao, Hai-Bo; Wu, Shi-Shu

2009-10-01

31

A study on the thermodynamics of liquid-gas phase transition for asymmetric polarized nuclear matter  

International Nuclear Information System (INIS)

The equation of state, developed before, for asymmetric polarized nuclear matter revealed a liquid-gas phase transition behaviour. Such transition is typical to that described by Van der Waal equation of real gas. In the present work, the analogy between nuclear matter and real macroscopic gas is examined. The nuclear matter equation of state is compared to Van der Waal equation to find the corresponding values of the real gas constants. Results are analysed in terms of the physical meanings of such constants. The latent heat of vaporization and entropy of transformation are calculated for symmetric nuclear matter. The critical point data and Van der Waal constants are estimated for asymmetric polarized nuclear matter. (author). 17 refs, 9 figs, 4 tabs

1990-01-01

32

Correlations between the nuclear breathing mode energy and properties of asymmetric nuclear matter  

CERN Multimedia

Based on microscopic Hartree-Fock + random phase approximation calculations with Skyrme interactions, we study the correlations between the nuclear breathing mode energy E_{ISGMR} and properties of asymmetric nuclear matter with a recently developed analysis method. Our results indicate that the E_{ISGMR} of $^{208}$Pb exhibits moderate correlations with the density slope $L$ of the symmetry energy and the isoscalar nucleon effective mass $m_{s,0}^{\\ast}$ besides a strong dependence on the incompressibility $K_{0}$ of symmetric nuclear matter. Using the empirical values of $L=60\\pm 30$ MeV and $m_{s,0}^{\\ast}=(0.8\\pm 0.1)m$, we obtain a theoretical uncertainty of about $\\pm 16$ MeV for the extraction of $K_{0}$ from the E_{ISGMR} of $^{208}$Pb. Including additionally the uncertainties from other properties of asymmetric nuclear matter leads to a total theoretical uncertainty of about $\\pm 21$ MeV for the extraction of $K_{0}$. Furthermore, we find the E_{ISGMR} difference between $^{100}$Sn and $^{132}$Sn str...

Chen, Lie-Wen

2011-01-01

33

Equation of State for Isospin Asymmetric Nuclear Matter Using Lane Potential  

International Nuclear Information System (INIS)

[en] A mean field calculation for obtaining the equation of state (EOS) for symmetric nuclear matter from a density dependent M3Y interaction supplemented by a zero-range potential is described. The energy per nucleon is minimized to obtain the ground state of symmetric nuclear matter. The saturation energy per nucleon used for nuclear matter calculations is determined from the co-efficient of the volume term of Bethe-Weizsaecker mass formula which is evaluated by fitting the recent experimental and estimated atomic mass excesses from Audi-Wapstra-Thibault atomic mass table by minimizing the mean square deviation. The constants of density dependence of the effective interaction are obtained by reproducing the saturation energy per nucleon and the saturation density of spin and isospin symmetric cold infinite nuclear matter. The EOS of symmetric nuclear matter, thus obtained, provide reasonably good estimate of nuclear incompressibility. Once the constants of density dependence are determined, EOS for asymmetric nuclear matter is calculated by adding to the isoscalar part, the isovector component of the M3Y interaction that do not contribute to the EOS of symmetric nuclear matter. These EOS are then used to calculate the pressure, the energy density and the velocity of sound in symmetric as well as isospin asymmetric nuclear matter. (author)

2006-01-01

34

Asymmetric nuclear matter in a Hartree-Fock approach to non-linear QHD  

CERN Multimedia

The Equation of State (EOS) for asymmetric nuclear matter is discussed starting from a phenomenological hadronic field theory of Serot-Walecka type including exchange terms. In a model with self interactions of the scalar sigma-meson we show that the Fock terms naturally lead to isospin effects in the nuclear EOS. These effects are quite large and dominate over the contribution due to isovector mesons. We obtain a potential symmetry term of "stiff" type, i.e. increasing with baryon density and an interesting behaviour of neutron/proton effective masses of relevance for transport properties of asymmetric dense matter.

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

2001-01-01

35

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

CERN Multimedia

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

36

Isospin asymmetric nuclear matter and properties of axisymmetric neutron stars  

CERN Multimedia

Pure hadronic compact stars, above a limiting value ($\\approx$1.6 M$_\\odot$) of their gravitational masses, to which predictions of most of other EoSs are restricted, can be reached from the EoS obtained using DDM3Y effective interaction. This effective interaction is found to be quite successful in providing unified description of elastic and inelastic scattering, various radioactivities and nuclear matter properties. We present a systematic study of the properties of pure hadronic compact stars. The $\\beta$-equilibrated neutron star matter using this EoS with a thin crust is able to describe highly-massive compact stars, such as PSR B1516+02B with a mass M=1.94$^{+0.17}_{-0.19}$ M$_\\odot$ and PSR J0751+1807 with a mass M=2.1$\\pm$0.2 M$_\\odot$ to a 1$\\sigma$ confidence level.

Chowdhury, Partha Roy; Basu, D N

2010-01-01

37

Asymmetric Dark Matter  

CERN Document Server

We review the theoretical framework underlying models of asymmetric dark matter, describe astrophysical constraints which arise from observations of neutron stars, and discuss the prospects for detecting asymmetric dark matter.

Kumar, Jason

2013-01-01

38

Current status of Dirac-Brueckner-Hartree-Fock calculations in asymmetric nuclear matter  

CERN Multimedia

We review the current status of our microscopic calculations in asymmetric nuclear matter. Updated predictions of the equation of state are made available to potential users. We discuss the features of our EoS in relation to the predicted neutron star maximum masses.

Sammarruca, Francesca

2008-01-01

39

Instabilities in a Mean-field dynamics of Asymmetric Nuclear Matter  

CERN Multimedia

We discuss the features of instabilities in asymmetric nuclear matter, in particular the relation between the nature of fluctuations, the types of instabilities and the properties of the interaction. We show a chemical instability appears as an instability against isoscalar-like fluctuations. Then starting from phenomenological hadronic field theory (QHD), including exchange terms, we discuss the symmetry energy and the relation to the dynamical response inside the spinodal region.

Greco, V; Colonna, M; Di Toro, M; Fabbri, G; Matera, F

2001-01-01

40

Asymmetric WIMP dark matter  

CERN Multimedia

In existing dark matter models with global symmetries the relic abundance of dark matter is either equal to that of anti-dark matter (thermal WIMP), or vastly larger, with essentially no remaining anti-dark matter (asymmetric dark matter). By exploring the consequences of a primordial asymmetry on the coupled dark matter and anti-dark matter Boltzmann equations we find large regions of parameter space that interpolate between these two extremes. Interestingly, this new asymmetric WIMP framework can accommodate a wide range of dark matter masses and annihilation cross sections. The present-day dark matter population is typically asymmetric, but only weakly so, such that indirect signals of dark matter annihilation are not completely suppressed. We apply our results to existing models, noting that upcoming direct detection experiments will constrain a large region of the relevant parameter space.

Graesser, Michael L; Vecchi, Luca

2011-01-01

 
 
 
 
41

Non-congruence of liquid-gas phase transition of asymmetric nuclear matter  

CERN Multimedia

We first explore the liquid-gas mixed phase in a bulk calculation, where two phases coexist without the geometrical structures. In the case of symmetric nuclear matter, the system behaves congruently, and the Maxwell construction becomes relevant. For asymmetric nuclear matter, on the other hand, the phase equilibrium is no more attained by the Maxwell construction since the liquid and gas phases are non-congruent; the particle fractions become completely different with each other. One of the origins of such non-congruence is attributed to the large symmetry energy. Subsequently we explore the charge-neutral nuclear matter with electrons by fully applying the Gibbs conditions to figure out the geometrical (pasta) structures in the liquid-gas mixed phase. We emphasize the effects of the surface tension and the Coulomb interaction on the pasta structures. We also discuss the thermal effects on the pasta structures.

Maruyama, Toshiki

2012-01-01

42

Single particle potentials of asymmetric nuclear matter in different spin-isospin channels  

CERN Multimedia

We investigate the neutron and proton single particle (s.p.) potentials of asymmetric nuclear matter and their isospin dependence in various spin-isospin $ST$ channels within the framework of the Brueckner-Hartree-Fock approach. It is shown that in symmetric nuclear matter, the s.p. potentials in both the isospin-singlet T=0 channel and isospin-triplet T=1 channel are essentially attractive, and the magnitudes in the two different channels are roughly the same. In neutron-rich nuclear matter, the isospin-splitting of the proton and neutron s.p. potentials turns out to be mainly determined by the isospin-singlet T=0 channel contribution which becomes more attractive for proton and more repulsive for neutron at higher asymmetries.

Zuo, Wei; Lombardo, Umberto

2013-01-01

43

Higher-order effects on the incompressibility of isospin asymmetric nuclear matter  

International Nuclear Information System (INIS)

Analytical expressions for the saturation density of asymmetric nuclear matter as well as its binding energy and incompressibility at saturation density are given up to fourth order in the isospin asymmetry ?=(?n-?p)/? using 11 characteristic parameters defined by the density derivatives of the binding energy per nucleon of symmetric nuclear matter, the symmetry energy Esym (?), and the fourth-order symmetry energy Esym,4(?) at normal nuclear density ?0. Using an isospin- and momentum-dependent modified Gogny interaction (MDI) and the Skyrme-Hartree-Fock (SHF) approach with 63 popular Skyrme interactions, we have systematically studied the isospin dependence of the saturation properties of asymmetric nuclear matter, particularly the incompressibility Ksat(?)=K0+Ksat,2?2+Ksat,4?4+O(?6) at saturation density. Our results show that the magnitude of the higher order Ksat,4 parameter is generally small compared to that of the Ksat,2 parameter. The latter essentially characterizes the isospin dependence of the incompressibility at saturation density and can be expressed as Ksat,2=Ksym-6L-(J0/K0)L, where L and Ksym represent, respectively, the slope and curvature parameters of the symmetry energy at ?0 and J0 is the third-order derivative parameter of symmetric nuclear matter at ?0. Furthermore, we have constructed a phenomenological modified Skyrme-like (MSL) model that can reasonably describe the general properties of symmetric nuclear matter and the symmetry energy predicted by both the MDI model and the SHF approach. The results indicate that the higher order J0 contribution to Ksat,2 generally cannot be neglected. In addition, it is found that there exists a nicely linear correlation between Ksym and L as well as between J0/K0 and K0. These correlations together with the empirical constraints on K0,L,Esym (?0), and the nucleon effective mass lead to an estimate of Ksat,2=-370±120 MeV.

2009-01-01

44

Collective modes of asymmetric nuclear matter in Quantum HadroDynamics  

CERN Multimedia

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

45

Neutrino mean free path in asymmetric nuclear matter at high density  

Energy Technology Data Exchange (ETDEWEB)

We calculate the neutrino mean free path for neutrino-nucleon scattering in highly asymmetric nuclear matter ({ital N}{gt}{ital Z}) at densities typical for the core of a neutron star. Nuclear matter is described by means of a relativistic field theory of nucleons coupled to neutral, scalar ({sigma}), and vector ({omega}) mesons and to charged vector mesons ({ital d}). The correlation effects induced by the strong interaction of nucleons are taken into account within a self-consistent mean field approximation. The contribution of the exchange terms to the nucleon-nucleon interaction is also included. We present results for physical situations which are expected to occur in the cooling of neutron stars. Exchange terms have the effect of increasing the neutrino mean free path by about 50{percent}. {copyright} {ital 1996 The American Physical Society.}

Fabbri, G.; Matera, F. [Dipartimento di Fisica, Universita degli Studi di Firenze and Istituto Nazionale di Fisica Nucleare, Sezione di Firenze, L.go E. Fermi 2, I-50125, Firenze (Italy)

1996-10-01

46

Neutrino mean free path in asymmetric nuclear matter at high density  

International Nuclear Information System (INIS)

We calculate the neutrino mean free path for neutrino-nucleon scattering in highly asymmetric nuclear matter (N>Z) at densities typical for the core of a neutron star. Nuclear matter is described by means of a relativistic field theory of nucleons coupled to neutral, scalar (?), and vector (?) mesons and to charged vector mesons (d). The correlation effects induced by the strong interaction of nucleons are taken into account within a self-consistent mean field approximation. The contribution of the exchange terms to the nucleon-nucleon interaction is also included. We present results for physical situations which are expected to occur in the cooling of neutron stars. Exchange terms have the effect of increasing the neutrino mean free path by about 50%. copyright 1996 The American Physical Society.

1996-01-01

47

High-order effects on the incompressibility of isospin asymmetric nuclear matter  

CERN Document Server

Analytical expressions for the saturation density as well as the binding energy and incompressibility at the saturation density of asymmetric nuclear matter are given exactly up to 4th-order in the isospin asymmetry delta =(rho_n - rho_p)/rho using 11 characteristic parameters defined at the normal nuclear density rho_0. Using an isospin- and momentum-dependent modified Gogny (MDI) interaction and the SHF approach with 63 popular Skyrme interactions, we have systematically studied the isospin dependence of the saturation properties of asymmetric nuclear matter, particularly the incompressibility $K_{sat}(\\delta )=K_{0}+K_{sat,2}\\delta ^{2}+K_{sat,4}\\delta ^{4}+O(\\delta ^{6})$ at the saturation density. Our results show that the magnitude of the high-order $K_{sat,4}$ parameter is generally small compared to that of the $K_{\\sat,2}$ parameter. The latter essentially characterizes the isospin dependence of the incompressibility at the saturation density and can be expressed as $K_{sat,2}=K_{sym}-6L-\\frac{J_{0}}...

Chen, Lie-Wen; Ko, Che Ming; Li, Bao-An; Shen, Chun; Xu, Jun

2009-01-01

48

Finite size effects in liquid-gas phase transition of asymmetric nuclear matter  

Energy Technology Data Exchange (ETDEWEB)

Full text: Since the nuclear equation of state has been studied in astrophysical context as an element of neutron star or super-nova theories - a call for an evidence was produced in experimental nuclear physics. Heavy-ion collisions became a tool of study on thermodynamic properties of nuclear matter. A particular interest has been inspired here by critical behavior of nuclear systems, as a phase transition of liquid-gas type. A lot of efforts was put to obtain an experimental evidence of such a phenomenon in heavy-ion collisions. With the use of radioactive beams and high performance identification systems in a near future it will be possible to extend experimental investigation to asymmetric nuclear systems, where neutron-to-proton ratio is far from the stability line. This experimental development needs a corresponding extension of theoretical studies. To obtain a complete theory of the liquid-gas phase transition in small nuclear systems, produced in violent heavy-ion collisions, one should take into account two facts. First, that the nuclear matter forming nuclei is composed of protons and neutrons; this complicates the formalism of phase transitions because one has to deal with two separate, proton and neutron, densities and chemical potentials. The second and more important is that the surface effects are very strong in a system composed of a few hundreds of nucleons. This point is especially difficult to hold, because surface becomes an additional, independent state parameter, depending strongly on the geometrical configuration of the system, and introducing a non-local term in the equation of state. In this presentation we follow the recent calculation by Lee and Mekjian on the finite-size effects in small (A = 10{sup 2} -10{sup 3}) asymmetric nuclear systems. A zero-range isospin-dependent Skyrme force is used to obtain a density and isospin dependent potential. The potential is then completed by additional terms giving contributions from surface and Coulomb energies. Taking into account the particle number conservation and assuming a specific geometrical configuration we introduce different and more precise formulae for these terms, keeping the main idea presented in unchanged. Applying a mean-field theory of nuclear matter, pressure and chemical potentials are obtained and used to resolve Gibbs conditions, giving properties of gas and liquid phases. (Author)

Pawlowski, P. [Inst. de Physique Nucleaire, IN2P3-CNRS, F-91406 Orsay (France)

2001-09-01

49

Finite size effects in liquid-gas phase transition of asymmetric nuclear matter  

International Nuclear Information System (INIS)

Full text: Since the nuclear equation of state has been studied in astrophysical context as an element of neutron star or super-nova theories - a call for an evidence was produced in experimental nuclear physics. Heavy-ion collisions became a tool of study on thermodynamic properties of nuclear matter. A particular interest has been inspired here by critical behavior of nuclear systems, as a phase transition of liquid-gas type. A lot of efforts was put to obtain an experimental evidence of such a phenomenon in heavy-ion collisions. With the use of radioactive beams and high performance identification systems in a near future it will be possible to extend experimental investigation to asymmetric nuclear systems, where neutron-to-proton ratio is far from the stability line. This experimental development needs a corresponding extension of theoretical studies. To obtain a complete theory of the liquid-gas phase transition in small nuclear systems, produced in violent heavy-ion collisions, one should take into account two facts. First, that the nuclear matter forming nuclei is composed of protons and neutrons; this complicates the formalism of phase transitions because one has to deal with two separate, proton and neutron, densities and chemical potentials. The second and more important is that the surface effects are very strong in a system composed of a few hundreds of nucleons. This point is especially difficult to hold, because surface becomes an additional, independent state parameter, depending strongly on the geometrical configuration of the system, and introducing a non-local term in the equation of state. In this presentation we follow the recent calculation by Lee and Mekjian on the finite-size effects in small (A = 102 -103) asymmetric nuclear systems. A zero-range isospin-dependent Skyrme force is used to obtain a density and isospin dependent potential. The potential is then completed by additional terms giving contributions from surface and Coulomb energies. Taking into account the particle number conservation and assuming a specific geometrical configuration we introduce different and more precise formulae for these terms, keeping the main idea presented in unchanged. Applying a mean-field theory of nuclear matter, pressure and chemical potentials are obtained and used to resolve Gibbs conditions, giving properties of gas and liquid phases. (Author)

2001-01-01

50

Examining the energy dependence of symmetry potential in asymmetric nuclear matter  

Science.gov (United States)

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.

Xu, Chang; Ren, Zhongzhou

2013-09-01

51

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

CERN Multimedia

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

52

Decomposition of EOS of Asymmetric Nuclear Matter into Different Spin-isospin Channels  

CERN Multimedia

We investigate the equation of state of asymmetric nuclear matter and its isospin dependence in various spin-isospin $ST$ channels within the framework of the Brueckner-Hartree-Fock approach extended to include a microscopic three-body force (TBF). It is shown that the potential energy per nucleon in the isospin-singlet T=0 channel is mainly determined by the contribution from the tensor SD coupled channel. At high densities, the TBF effect on the isospin-triplet T=1 channel contribution turns out to be much larger than that on the T=0 channel contribution. At low densities around and below the normal nuclear matter density, the isospin dependence is found to come essentially from the isospin-singlet SD channel and the isospin-triplet T=1 component is almost independent of isospin-asymmetry. As the density increases, the T=1 channel contribution becomes sensitive to the isospin-asymmetry and at high enough densities its isospin-dependence may even become more pronounced than that of the T=0 contribution. The ...

Zuo, Wei; Li, Jun-Qing; Zhao, En-Guang; Scheid, Werner

2013-01-01

53

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

2009-01-01

54

Asymmetric Higgsino dark matter.  

UK PubMed Central (United Kingdom)

In the supersymmetric framework, prior to the electroweak phase transition, the existence of a baryon asymmetry implies the existence of a Higgsino asymmetry. We investigate whether the Higgsino could be a viable asymmetric dark matter candidate. We find that this is indeed possible. Thus, supersymmetry can provide the observed dark matter abundance and, furthermore, relate it with the baryon asymmetry, in which case the puzzle of why the baryonic and dark matter mass densities are similar would be explained. To accomplish this task, two conditions are required. First, the gauginos, squarks, and sleptons must all be very heavy, such that the only electroweak-scale superpartners are the Higgsinos. With this spectrum, supersymmetry does not solve the fine-tuning problem. Second, the temperature of the electroweak phase transition must be low, in the (1-10) GeV range. This condition requires an extension of the minimal supersymmetric standard model.

Blum K; Efrati A; Grossman Y; Nir Y; Riotto A

2012-08-01

55

Asymmetric Higgsino dark matter.  

Science.gov (United States)

In the supersymmetric framework, prior to the electroweak phase transition, the existence of a baryon asymmetry implies the existence of a Higgsino asymmetry. We investigate whether the Higgsino could be a viable asymmetric dark matter candidate. We find that this is indeed possible. Thus, supersymmetry can provide the observed dark matter abundance and, furthermore, relate it with the baryon asymmetry, in which case the puzzle of why the baryonic and dark matter mass densities are similar would be explained. To accomplish this task, two conditions are required. First, the gauginos, squarks, and sleptons must all be very heavy, such that the only electroweak-scale superpartners are the Higgsinos. With this spectrum, supersymmetry does not solve the fine-tuning problem. Second, the temperature of the electroweak phase transition must be low, in the (1-10) GeV range. This condition requires an extension of the minimal supersymmetric standard model. PMID:23006163

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

2012-07-31

56

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.

Kim Youngman; Seo Yunseok; Shin Ik Jae; Sin Sang-Jin

2012-01-01

57

Asymmetric nuclear matter and neutron-skin in extended relativistic mean field model  

CERN Multimedia

The density dependence of the symmetry energy, instrumental in understanding the behaviour of the asymmetric nuclear matter, is investigated within the extended relativistic mean field (ERMF) model which includes the contributions from the self and mixed interaction terms for the scalar-isoscalar ($\\sigma$), vector-isoscalar ($\\omega$) and vector-isovector ($\\rho$) mesons upto the quartic order. Each of the 26 different parameterizations of the ERMF model employed are compatible with the bulk properties of the finite nuclei. The behaviour of the symmetry energy for several parameter sets are found to be consistent with the empirical constraints on them as extracted from the analyses of the isospin diffusion data. The neutron-skin thickness in the $^{208}$Pb nucleus for these parameter sets of the ERMF model lie in the range of $\\sim 0.20 - 0.24$ fm which is in harmony with the ones predicted by the Skyrme Hartree-Fock model. We also investigate the role of various mixed interaction terms which are crucial for...

Agrawal, B K

2010-01-01

58

Oscillating Asymmetric Dark Matter  

CERN Multimedia

We study the dynamics of dark matter (DM) particle-antiparticle oscillations within the context of asymmetric DM. Oscillations arise due to small DM number-violating Majorana-type mass terms, and can lead to recoupling of annihilation after freeze-out and washout of the DM density. We derive the density matrix equations for DM oscillations and freeze-out from first principles using nonequilibrium field theory, and our results are qualitatively different than in previous studies. DM dynamics exhibits particle-vs-antiparticle "flavor" effects, depending on the interaction type, analogous to neutrino oscillations in a medium. "Flavor-sensitive" DM interactions include scattering or annihilation through a new vector boson, while "flavor-blind" interactions include scattering or s-channel annihilation through a new scalar boson, or annihilation to pairs of bosons. In particular, we find that flavor-sensitive annihilation does not recouple when coherent oscillations begin, and that flavor-blind scattering does not ...

Tulin, Sean; Zurek, Kathryn M

2012-01-01

59

Originally Asymmetric Dark Matter  

CERN Multimedia

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

60

Asymmetric dark matter  

International Nuclear Information System (INIS)

We consider a simple class of models in which the relic density of dark matter is determined by the baryon asymmetry of the Universe. In these models a B-L asymmetry generated at high temperatures is transferred to the dark matter, which is charged under B-L. The interactions that transfer the asymmetry decouple at temperatures above the dark matter mass, freezing in a dark matter asymmetry of order the baryon asymmetry. This explains the observed relation between the baryon and dark matter densities for the dark matter mass in the range 5-15 GeV. The symmetric component of the dark matter can annihilate efficiently to light pseudoscalar Higgs particles a or via t-channel exchange of new scalar doublets. The first possibility allows for h0?aa decays, while the second predicts a light charged Higgs-like scalar decaying to ??. Direct detection can arise from Higgs exchange in the first model or a nonzero magnetic moment in the second. In supersymmetric models, the would-be lightest supersymmetric partner can decay into pairs of dark matter particles plus standard model particles, possibly with displaced vertices.

2009-06-01

 
 
 
 
61

Three-body force effect on nucleon momentum distributions in asymmetric nuclear matter within the framework of the extended BHF approach  

CERN Document Server

We have investigated the three-body force (TBF) effect on the neutron and proton momentum distributions in asymmetric nuclear matter within the framework of the extended Brueckner-Hartree-Fock approach by adopting the $AV18$ two-body interaction plus a microscopic TBF. In asymmetric nuclear matter, it is shown that the neutron and proton momentum distributions become different from their common distribution in symmetric nuclear matter. The predicted depletion of the proton hole states increases while the neutron one decreases as a function of isospin-asymmetry. The TBF effect on the neutron and proton momentum distributions turns out to be negligibly weak at low densities around and below the normal nuclear density. The TBF effect is found to become sizable only at high densities well above the saturation density, and inclusion of the TBF leads to an overall enhancement of the depletion of the neutron and proton Fermi seas.

Yin, Peng; Wang, Pei; Zuo, Wei; 10.1103/PhysRevC.87.014314

2013-01-01

62

Effects of retardation on normal and quasi-deuteron pairing in asymmetric nuclear matter  

International Nuclear Information System (INIS)

[en] Full text: The main goal of this work is to study retardation effects in a relativistic version of the effective quasi-particle approximation and to verify their effect on the isoscalar and isovector pairing fields in relativistic nuclear matter. Both relativistic calculations and nonrelativistic calculations give extremely large isoscalar n-p pairing fields of about 10 MeV. Within an effective quasi-particle approximation we can take into account a part of the partial occupations seen in a self-consistent Greens function approach through the energy dependence of the Hartree-Fock-Bogoliubov mean fields. Nonrelativistic calculations performed in this approximation gives a reduction of the isoscalar n-p pairing field similar to that obtained in the self-consistent Greens function formalism. Here we investigate the retardation effects in Hartree-Fock-Bogoliubov approximation. (author)

2009-01-01

63

NUCLEAR AND HEAVY ION PHYSICS: Decomposition of the equation of state of asymmetric nuclear matter into different spin-isospin channels  

Science.gov (United States)

We investigate the equation of state of asymmetric nuclear matter and its isospin dependence in various spin-isospin ST channels within the framework of the Brueckner-Hartree-Fock approach extended to include a microscopic three-body force (TBF). It is shown that the potential energy per nucleon in the isospin-singlet T = 0 channel is mainly determined by the contribution from the tensor SD coupled channel. At high densities, the TBF effect on the isospin-triplet T = 1 channel contribution turns out to be much larger than that on the T = 0 channel contribution. At low densities around and below the normal nuclear matter density, the isospin dependence is found to come essentially from the isospin-singlet SD channel and the isospin-triplet T = 1 component is almost independent of isospin asymmetry. As the density increases, the T = 1 channel contribution becomes sensitive to the isospin asymmetry and at high enough densities its isospin dependence may even become more pronounced than that of the T = 0 contribution. The present results may provide some microscopic constraints for improving effective nucleon-nucleon interactions in a nuclear medium and for constructing new functionals of effective nucleon-nucleon interaction based on microscopic many-body theories.

Zuo, Wei; Zhou, Shan-Gui; Li, Jun-Qing; Zhao, En-Guang; Scheid, W.

2009-07-01

64

The Deconfinement Phase Transition in Asymmetric Matter  

CERN Document Server

We study the phase transition of asymmetric hadronic matter to a quark-gluon plasma within the framework of a simple two-phase model. The analysis is performed 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. The EOS is obtained in a separate description for the hadronic phase and for the quark-gluon plasma. For the hadrons, a relativistic mean-field model calibrated to the properties of nuclear matter is used, and a bag-model type EOS is used for the quarks and gluons. The model is applied to the deconfinement phase transition that may occur in matter created in ultra-relativistic collisions of heavy ions. Based on the two-dimensional coexistence surface (binodal), various phase separation scenarios and the Maxwell construction through the mixed phase are discussed. In the framework of the two-phase model the phase transition in asymmetric matter is continuous (second-order by...

Müller, H

1997-01-01

65

Regenerating a symmetry in asymmetric dark matter.  

UK PubMed Central (United Kingdom)

Asymmetric dark matter theories generically allow for mass terms that lead to particle-antiparticle mixing. Over the age of the Universe, dark matter can thus oscillate from a purely asymmetric configuration into a symmetric mix of particles and antiparticles, allowing for pair-annihilation processes. Additionally, requiring efficient depletion of the primordial thermal (symmetric) component generically entails large annihilation rates. We show that unless some symmetry completely forbids dark matter particle-antiparticle mixing, asymmetric dark matter is effectively ruled out for a large range of masses, for almost any oscillation time scale shorter than the age of the Universe.

Buckley MR; Profumo S

2012-01-01

66

Asymmetric dark matter and effective operators  

International Nuclear Information System (INIS)

In order to annihilate in the early Universe to levels well below the measured dark matter density, asymmetric dark matter must possess large couplings to the standard model. In this paper, we consider effective operators which allow asymmetric dark matter to annihilate into quarks. In addition to a bound from requiring sufficient annihilation, the energy scale of such operators can be constrained by limits from direct detection and monojet searches at colliders. We show that the allowed parameter space for these operators is highly constrained, leading to nontrivial requirements that any model of asymmetric dark matter must satisfy.

2011-08-15

67

Regenerating a symmetry in asymmetric dark matter.  

Science.gov (United States)

Asymmetric dark matter theories generically allow for mass terms that lead to particle-antiparticle mixing. Over the age of the Universe, dark matter can thus oscillate from a purely asymmetric configuration into a symmetric mix of particles and antiparticles, allowing for pair-annihilation processes. Additionally, requiring efficient depletion of the primordial thermal (symmetric) component generically entails large annihilation rates. We show that unless some symmetry completely forbids dark matter particle-antiparticle mixing, asymmetric dark matter is effectively ruled out for a large range of masses, for almost any oscillation time scale shorter than the age of the Universe. PMID:22304253

Buckley, Matthew R; Profumo, Stefano

2012-01-04

68

Microscopic approach to the nucleon-nucleon effective interaction and nucleon-nucleon scattering in symmetric and isospin-asymmetric nuclear matter  

CERN Document Server

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 results of a complex balance among various effects, and cannot be simulated with a simple phenomenological model.

Sammarruca, Francesca

2013-01-01

69

Properties of isospin asymmetric nuclear matter and extended Brueckner-Hartree-Fock approach. Pt.2: Equation of state, symmetry energy and three-body force effects  

CERN Multimedia

Within the isospin dependent Brueckner-Hartree-Fock approach, the equation of state of isospin asymmetric nuclear matter and its isospin dependence have been investigated in the whole isospin range. The present work has been focused on the effects of a microscopic three-body force on the equation of state of asymmetric nuclear matter and nuclear symmetry energy. It is shown that, even with the presence of the three-body force, the empirical parabolic law of the energy per nucleon vs isospin asymmetry is still fulfilled accurately in the whole isospin range (0 <= beta <=1). Around the empirical saturation density rho sub 0 = 0.17 fm sup - sup 3 , the three-body force effect on the symmetry energy is rather small and the symmetry energy at the saturation density obtained in the presence of the three-body force is 30.71 MeV in good agreement with its empirical value 30 +- 4 MeV; while at high density, the three-body force provides a strong enhancement of the symmetry energy and makes the symmetry energy in...

Zuo Wei; Li Ze; Li Jun; Lombardo, U

2002-01-01

70

BCS-BEC Crossover and Thermodynamics in Asymmetric Nuclear Matter with Pairings in Isospin I=0 and I=1 Channels  

CERN Document Server

The BCS-BEC crossover and phase diagram for asymmetric nuclear superfluid with pairings in isospin I = 0 and I = 1 channels are investigated at mean field level, by using a density dependent nucleon-nucleon potential. Induced by the in-medium nucleon mass and density dependent coupling constants, neutron-proton Cooper pairs could be in BEC state at sufficiently low density, but there is no chance for the BEC formation of neutron-neutron and proton-proton pairs at any density and asymmetry. We calculate the phase diagram in asymmetry-temperature plane for weakly interacting nuclear superfluid, and find that including the I = 1 channel changes significantly the phase structure at low temperature. There appears a new phase with both I = 0 and I = 1 pairings at low temperature and low asymmetry, and the gapless state in any phase with I = 1 pairing is washed out and all excited nucleons are fully gapped.

Mao, Shijun; Zhuang, Pengfei

2008-01-01

71

Phenomenological approach to nuclei and nuclear matter  

International Nuclear Information System (INIS)

[en] Neutron-rich nuclei and asymmetric nuclear matter are studied using a phenomenological macroscopic nuclear model paying special attention to the saturation condition of asymmetric nuclear matter. An interesting conclusion of this study is that the density derivative of symmetry energy at the nuclear density controls not only the masses and sizes of laboratory neutron-rich nuclei but also the core-crust boundary density of neutron stars and existence of pasta nuclei in the neutron-star crust. (author)

2010-03-19

72

Solar constraints on asymmetric dark matter  

CERN Multimedia

The dark matter content of the Universe is likely to be a mixture of matter and antimatter, perhaps comparable to the measured asymmetric mixture of baryons and antibaryons. During the early stages of the Universe, the dark matter particles are produced in a process similar to baryogenesis, and dark matter freeze-out depends on the dark matter asymmetry and the annihilation cross section (s-wave and p-wave annihilation channels). In these \\eta-parametrised asymmetric dark matter models (\\eta-ADM), the dark matter particles have an annihilation cross section close to the weak interaction cross section, and a value of \\eta-dark matter asymmetry close to the baryon asymmetry \\eta_B. Furthermore, we assume that dark matter scattering of baryons, namely, the spin-independent scattering cross section, is of the same order as the range of values suggested by several theoretical particle physics models used to explain the current unexplained events reported in the DAMA/LIBRA, CoGeNT and CRESST experiments. Here, we c...

Lopes, Ilidio; 10.1088/0004-637X/757/2/130

2012-01-01

73

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

74

Effects of isospin and momentum dependent interactions on liquid-gas phase transition in hot asymmetric nuclear matter  

CERN Multimedia

The liquid-gas phase transition in hot neutron-rich nuclear matter is investigated 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). The boundary of the phase-coexistence region is shown to be sensitive to the density dependence of the nuclear symmetry energy with a softer symmetry energy giving a higher critical pressure and a larger area of phase-coexistence region. Compared with the momentum-independent MID interaction, the isospin and momentum-dependent MDI interaction is found to increase the critical pressure and enlarge the area of phase-coexistence region. For the isoscalar momentum-dependent eMDYI interaction, a limiting pressure above which the liquid-gas phase transition cannot take place has been found and it is shown to be sensitive to the stiffness of the symmetry energy.

Xu, J; Li, B A; Ma, H R; Chen, Lie-Wen; Li, Bao-An; Ma, Hong-Ru; Xu, Jun

2007-01-01

75

Sneutrino inflation with asymmetric dark matter  

International Nuclear Information System (INIS)

The asymmetric dark matter scenario is known to give an interesting solution for the cosmic coincidence problem between baryon and dark matter densities. In the scenario, the dark matter asymmetry, which is translated to the dark matter density in the present universe, is transferred from the B-L asymmetry generated in the early universe. On the other hand, the generation of the B-L asymmetry is simply assumed, though many mechanisms for the generation are expected to be consistent with the scenario. We show that the generation of the asymmetry in the sneutrino inflation scenario works similarly to the asymmetric dark matter scenario, because the nonrenormalizable operator which translates the B-L asymmetry to the dark matter asymmetry is naturally obtained by integrating right-handed neutrinos out. As a result, important issues concerning cosmology (inflation, the mass density of dark matter, and the baryon asymmetry of the universe) as well as neutrino masses and mixing have a unified origin, namely, the right-handed neutrinos.

2011-09-01

76

Isospin violating dark matter being asymmetric  

Science.gov (United States)

The isospin violating dark matter (IVDM) scenario offers an interesting possibility to reconcile conflicting results among direct dark matter search experiments for a mass range around 10 GeV. We consider two simple renormalizable IVDM models with a complex scalar dark matter and a Dirac fermion dark matter, respectively, whose stability is ensured by the conservation of “dark matter number.” Although both models successfully work as the IVDM scenario with destructive interference between effective couplings to proton and neutron, the dark matter annihilation cross section is found to exceed the cosmological/astrophysical upper bounds. Then, we propose a simple scenario to reconcile the IVDM scenario with the cosmological/astrophysical bounds, namely, the IVDM being asymmetric. Assuming a suitable amount of dark matter asymmetry has been generated in the early Universe, the annihilation cross section beyond the cosmological/astrophysical upper bound nicely works to dramatically reduce the antidark matter relic density and as a result, the constraints from dark matter indirect searches are avoided. We also discuss collider experimental constraints on the models and an implication to Higgs boson physics.

Okada, Nobuchika; Seto, Osamu

2013-09-01

77

Phenomenology of light fermionic asymmetric dark matter  

Science.gov (United States)

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

2013-10-01

78

SOLAR CONSTRAINTS ON ASYMMETRIC DARK MATTER  

International Nuclear Information System (INIS)

The dark matter content of the universe is likely to be a mixture of matter and antimatter, perhaps comparable to the measured asymmetric mixture of baryons and antibaryons. During the early stages of the universe, the dark matter particles are produced in a process similar to baryogenesis, and dark matter freezeout depends on the dark matter asymmetry and the annihilation cross section (s-wave and p-wave annihilation channels) of particles and antiparticles. In these ?-parameterized asymmetric dark matter (?ADM) models, the dark matter particles have an annihilation cross section close to the weak interaction cross section, and a value of dark matter asymmetry ? close to the baryon asymmetry ?B. Furthermore, we assume that dark matter scattering of baryons, namely, the spin-independent scattering cross section, is of the same order as the range of values suggested by several theoretical particle physics models used to explain the current unexplained events reported in the DAMA/LIBRA, CoGeNT, and CRESST experiments. Here, we constrain ?ADM by investigating the impact of such a type of dark matter on the evolution of the Sun, namely, the flux of solar neutrinos and helioseismology. We find that dark matter particles with a mass smaller than 15 GeV, a spin-independent scattering cross section on baryons of the order of a picobarn, and an ?-asymmetry with a value in the interval 10–12-10–10, would induce a change in solar neutrino fluxes in disagreement with current neutrino flux measurements. This result is also confirmed by helioseismology data. A natural consequence of this model is suppressed annihilation, thereby reducing the tension between indirect and direct dark matter detection experiments, but the model also allows a greatly enhanced annihilation cross section. All the cosmological ?ADM scenarios that we discuss have a relic dark matter density ?h 2 and baryon asymmetry ?B in agreement with the current WMAP measured values, ?DM h 2 = 0.1109 ± 0.0056 and ?B = 0.88 × 10–10.

2012-10-01

79

Probing the equation of state of asymmetric nuclear matter with isospin diffusion and stopping in heavy-ion collisions  

International Nuclear Information System (INIS)

Results from the study of isospin asymmetric Sn+Sn collisions at E/A=35 MeV and 50 MeV, collected with the LASSA and the Chimera detectors at the NSCL of MSU, respectively, are shown. The diffusion of neutrons and protons between projectiles and targets with different N/Z-asymmetries is studied by means of imbalance ratios measurements. The obtained results and their comparison to transport model simulations provide constraints on the density dependence of the symmetry energy. The systematic study of these phenomena at different impact parameters also allows us to explore isospin transparency and stopping phenomena in more central collisions, with important implications about the attainment of chemical equilibrium in central collisions at 35 MeV/nucleon.

2011-09-23

80

Constraints on asymmetric dark matter from asteroseismology  

CERN Document Server

We report recent results on the impact of asymmetric dark matter (DM) particles on low-mass stars. First, we found that the small convective core expected in stars with masses between 1.1 and 1.3 Msun is suppressed due to DM cooling. Moreover, stars with masses below 1 Msun have their central temperatures and densities more strongly influenced by DM than in the solar case. We were able to put limits to the DM mass and spin-dependent DM-proton scattering cross section by comparing the modelling of the nearby star Alpha Cen B with photometric, spectroscopic and asteroseismic observations.

Casanellas, Jordi

2013-01-01

 
 
 
 
81

Excluding Light Asymmetric Bosonic Dark Matter  

DEFF Research Database (Denmark)

We argue that current neutron star observations exclude asymmetric bosonic non-interacting dark matter in the range from 2 keV to 16 GeV, including the 5-15 GeV range favored by DAMA and CoGeNT. If bosonic WIMPs are composite of fermions, the same limits apply provided the compositeness scale is higher than ~10^12 GeV (for WIMP mass ~1 GeV). In case of repulsive self-interactions, we exclude large range of WIMP masses and interaction cross sections which complements the constraints imposed by observations of the Bullet Cluster.

Kouvaris, Christoforos; Tinyakov, Peter

2011-01-01

82

Asymmetric Dark Matter and Dark Radiation  

CERN Multimedia

Asymmetric Dark Matter (ADM) models invoke a particle-antiparticle asymmetry, similar to the one observed in the Baryon sector, to account for the Dark Matter (DM) abundance. Both asymmetries are usually generated by the same mechanism and generally related, thus predicting DM masses around 5 GeV in order to obtain the correct density. The main challenge for successful models is to ensure efficient annihilation of the thermally produced symmetric component of such a light DM candidate without violating constraints from collider or direct searches. A common way to overcome this involves a light mediator, into which DM can efficiently annihilate and which subsequently decays into Standard Model particles. Here we explore the scenario where the light mediator decays instead into lighter degrees of freedom in the dark sector that act as radiation in the early Universe. While this assumption makes indirect DM searches challenging, it leads to signals of extra radiation at BBN and CMB. Under certain conditions, pre...

Blennow, Mattias; Mena, Olga; Redondo, Javier; Serra, Paolo

2012-01-01

83

Warm asymmetric matter in the Quark Meson Coupling Model  

CERN Document Server

In this work we study the warm equation of state of asymmetric nuclear matter in the quark meson coupling model which incorporates explicitly quark degrees of freedom, with quarks coupled to scalar, vector and isovector mesons. Mechanical and chemical instabilities are discussed as a function of density and isospin asymmetry. The binodal section, essential in the study of the liquid-gas phase transition is also constructed and discussed. The main results for the equation of state are compared with two common parametrizations used in the non-linear Walecka model and the differences are outlined.

Panda, P K; Peres-Menezes, D; Providência, C

2003-01-01

84

On Symmetric and Asymmetric Light Dark Matter  

CERN Document Server

We examine cosmological, astrophysical and collider constraints on thermal dark matter (DM) with mass mX in the range 1 MeV to 10 GeV. Cosmic microwave background (CMB) observations, which severely constrain light symmetric DM, can be evaded if the DM relic density is sufficiently asymmetric. CMB constraints require the present anti-DM to DM ratio to be less than 2*10^{-6} (10^{-1}) for DM mass mX = 1 MeV (10 GeV) with ionizing efficiency factor f ~ 1. We determine the minimum annihilation cross section for achieving these asymmetries subject to the relic density constraint; these cross sections are larger than the usual thermal annihilation cross section. On account of collider constraints, such annihilation cross sections can only be obtained by invoking light mediators. These light mediators can give rise to significant DM self-interactions, and we derive a lower bound on the mediator mass from elliptical DM halo shape constraints. We find that halo shapes require a mediator with mass mphi > 4 * 10^{-2} Me...

Lin, Tongyan; Zurek, Kathryn M

2011-01-01

85

The nuclear matter problem  

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

86

Charge Asymmetric Cosmic Rays as a probe of Flavor Violating Asymmetric Dark Matter  

DEFF Research Database (Denmark)

The recently introduced cosmic sum rules combine the data from PAMELA and Fermi-LAT cosmic ray experiments in a way that permits to neatly investigate whether the experimentally observed lepton excesses violate charge symmetry. One can in a simple way determine universal properties of the unknown component of the cosmic rays. Here we attribute a potential charge asymmetry to the dark sector. In particular we provide models of asymmetric dark matter able to produce charge asymmetric cosmic rays. We consider spin zero, spin one and spin one-half decaying dark matter candidates. We show that lepton flavor violation and asymmetric dark matter are both required to have a charge asymmetry in the cosmic ray lepton excesses. Therefore, an experimental evidence of charge asymmetry in the cosmic ray lepton excesses implies that dark matter is asymmetric.

Masina, Isabella; Sannino, Francesco

2011-01-01

87

Collective flow measurements in asymmetric nuclear collisions  

International Nuclear Information System (INIS)

The collective flow measurements presented in this lecture have been performed with the DIOGENE electronic 4?-detector installed at the Saturne synchrotron in Saclay, which can deliver beams up to mass 40. In order to study the properties of dense (and hot) nuclear matter, it is required to measure nucleus-nucleus collisions involving a large number of nucleons. That is the reason why we focused our experiment on asymmetric collisions, with target nuclei heavier than the beam. We measured triple differential cross sections of pseudoprotons (free protons as well as protons bound in light nuclei), inside the acceptance of the DIOGENE pictorial drift chamber (PDC), restricted to 200 0 in polar angle and to kinetic energy larger than ? 40 MeV. We analysed these cross sections in three different ways, which lead to various features of the collective flow: the usual flow parameter F, azimuthal angular distributions dN/d? showing possible evidence for preferential emission transversely to the reaction plane, and finally two-dimensional Gaussian fits giving a more complete characterization of the participants collective flow, with the flow angle and two aspect ratios

1989-06-03

88

An effective Nuclear Model: from Nuclear Matter to Finite Nuclei  

CERN Document Server

The momentum and density dependence of mean fields in symmetric and asymmetric nuclear matter are analysed using the simple density dependent finite range effective interaction containing a single Gaussian term alongwith the zero-range terms. Within the formalism developed, it is possible to reproduce the various diverging predictions on the momentum and density dependence of isovector part of the mean field in asymmetric matter. The finite nucleus calculation is formulated for the simple Gaussian interaction in the framework of quasilocal density functional theory. The prediction of energies and charge radii of the interaction for the spherical nuclei compares well with the results of other effective theories.

Routray, T R; Tripathy, S K; Bhuyan, M; Patra, S K; Behera, B

2012-01-01

89

Upper Bounds on Asymmetric Dark Matter Self Annihilation Cross Sections  

CERN Document Server

Most models for asymmetric dark matter allow for dark matter self annihilation processes, which can wash out the asymmetry at temperatures near and below the dark matter mass. We study the coupled set of Boltzmann equations for the symmetric and antisymmetric dark matter number densities, and derive conditions applicable to a large class of models for the absence of a significant wash-out of an asymmetry. These constraints are applied to various existing scenarios. In the case of left- or right-handed sneutrinos, very large electroweak gaugino masses, or very small mixing angles are required.

Ellwanger, Ulrich

2012-01-01

90

Asymmetric neutrino emission in quark matter and pulsar kicks  

CERN Document Server

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

91

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

92

Gamma ray constraints on flavor violating asymmetric dark matter  

DEFF Research Database (Denmark)

We show how cosmic gamma rays can be used to constrain models of asymmetric Dark Matter decaying into lepton pairs by violating flavor. First of all we require the models to explain the anomalies in the charged cosmic rays measured by PAMELA, Fermi and H.E.S.S.; performing combined fits we determine the allowed values of the Dark Matter mass and lifetime. For these models, we then determine the constraints coming from the measurement of the isotropic gamma-ray background by Fermi for a complete set of lepton flavor violating primary modes and over a range of DM masses from 100 GeV to 10 TeV. We find that the Fermi constraints rule out the flavor violating asymmetric Dark Matter interpretation of the charged cosmic ray anomalies.

Masina, I.; Panci, P.

2012-01-01

93

Main sequence stars with asymmetric dark matter  

CERN Multimedia

We study the effects of feebly or non-annihilating weakly interacting Dark Matter (DM) particles on stars that live in DM environments denser than that of our Sun. We find that the energy transport mechanism induced by DM particles can produce unusual conditions in the core of Main Sequence stars, with effects which can potentially be used to probe DM properties. We find that solar mass stars placed in DM densities of rhochi>= e2 GeV/cm3 are sensitive to Spin-Dependent scattering cross-section sigmsd >= e-37 cm2 and a DM particle mass as low as mchi=5 GeV, accessing a parameter range weakly constrained by current direct detection experiments.

Iocco, Fabio; Leclercq, Florent; Meynet, Georges

2012-01-01

94

Main sequence stars with asymmetric dark matter.  

Science.gov (United States)

We study the effects of feebly or nonannihilating weakly interacting dark matter (DM) particles on stars that live in DM environments denser than that of our Sun. We find that the energy transport mechanism induced by DM particles can produce unusual conditions in the cores of main sequence stars, with effects which can potentially be used to probe DM properties. We find that solar mass stars placed in DM densities of ?(?)?10(2) GeV/cm(3) are sensitive to spin-dependent scattering cross section ?(SD)?10(-37) cm(2) and a DM particle mass as low as m(?)=5 GeV, accessing a parameter range weakly constrained by current direct detection experiments. PMID:22401051

Iocco, Fabio; Taoso, Marco; Leclercq, Florent; Meynet, Georges

2012-02-07

95

Main sequence stars with asymmetric dark matter.  

UK PubMed Central (United Kingdom)

We study the effects of feebly or nonannihilating weakly interacting dark matter (DM) particles on stars that live in DM environments denser than that of our Sun. We find that the energy transport mechanism induced by DM particles can produce unusual conditions in the cores of main sequence stars, with effects which can potentially be used to probe DM properties. We find that solar mass stars placed in DM densities of ?(?)?10(2) GeV/cm(3) are sensitive to spin-dependent scattering cross section ?(SD)?10(-37) cm(2) and a DM particle mass as low as m(?)=5 GeV, accessing a parameter range weakly constrained by current direct detection experiments.

Iocco F; Taoso M; Leclercq F; Meynet G

2012-02-01

96

Decaying asymmetric dark matter relaxes the AMS-Fermi tension  

Science.gov (United States)

The first result of AMS-02 confirms the positron fraction excess observed by PAMELA, but the spectrum is somewhat softer than that of PAMELA. In the dark matter (DM) interpretation it brings a tension between AMS-02 and Fermi-LAT, which reported an excess of the electron plus positron flux. In this work we point out that the asymmetric cosmic ray from asymmetric dark matter (ADM) decay relaxes the tension. It is found that in the case of two-body decay a bosonic ADM around 2.4 TeV and decaying into ???+ can significantly improve the fits. Based on the R?parity-violating supersymmetry with operators LLEc, we propose a minimal model to realize that ADM. The model introduces only a pair of singlets (X,bar X) with a tiny coupling LHuX, which makes the ADM share the lepton asymmetry and decay into ???+ along the operator LLEc.

Feng, Lei; Kang, Zhaofeng

2013-10-01

97

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

98

Nuclear physics of dense matter  

International Nuclear Information System (INIS)

Recent progress in applying nuclear physics to calculate properties of dense matter is reviewed. Topics considered include nuclei below neutron drip, the equation of state of matter at densities both below and above that of nuclear matter, the possibility of rapid neutron star cooling by the direct Urca process, superfluid gaps for neutrons and superconducting gaps for protons. (orig.)

1991-01-01

99

Possible implications of asymmetric fermionic dark matter for neutron stars  

Science.gov (United States)

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.

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

2013-10-01

100

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

 
 
 
 
101

Nuclear Matter Equation of State and Three body Forces  

CERN Document Server

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

102

Asymmetric Dark Matter via Spontaneous Co-Genesis  

CERN Multimedia

We investigate, in the context of asymmetric dark matter (DM), a new mechanism of spontaneous co-genesis of linked DM and baryon asymmetries, explaining the observed relation between the baryon and DM densities, Omega_DM/Omega_B ~ 5. The co-genesis mechanism requires a light scalar field, phi, with mass below 5 eV which couples derivatively to DM, much like a 'dark axion'. The field phi, and its coupling to DM, can itself provide a channel to annihilate away the residual symmetric DM component, leading to a highly predictive scenario.

March-Russell, John

2011-01-01

103

Asymmetric dark matter from a GeV hidden sector  

International Nuclear Information System (INIS)

Asymmetric dark matter (ADM) models relate the dark matter (DM) density to the baryon asymmetry, so that a natural mass scale for ADM is around a few GeV. In existing models of ADM, this mass scale is unexplained; here we generate this GeV scale for DM) from the weak scale via gauge kinetic mixing with a new Abelian dark force. In addition, this dark sector provides an efficient mechanism for suppressing the symmetric abundance of DM through annihilations to the dark photon. We augment this sector with a higher dimensional operator responsible for communicating the baryon asymmetry to the dark sector. Our framework also provides a DM candidate for gauge mediation models. It results in a direct detection cross section of interest for current experiments: ?p -41 cm2 for DM masses in the range 1-15 GeV.

2010-09-01

104

Condensed Matter Nuclear Science  

Science.gov (United States)

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

105

Liquid-gas phase transition and Coulomb instability of asymmetric nuclear systems  

CERN Multimedia

We use a chiral SU(3) quark mean field model to study the properties of nuclear systems at finite temperature. The liquid-gas phase transition of symmetric and asymmetric nuclear matter is discussed. For two formulations of the model the critical temperature, $T_c$, for symmetric nuclear matter is found to be 15.8 MeV and 17.9 MeV. These values are consistent with those derived from recent experiments. The limiting temperatures for finite nuclei are in good agreement with the experimental points.

Wang, P; Thomas, A W; Williams, A G

2005-01-01

106

Phase transitions in nuclear matter  

Energy Technology Data Exchange (ETDEWEB)

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.

Glendenning, N.K.

1984-11-01

107

Shear viscosity of nuclear matter  

CERN Document Server

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

108

Probing nuclear matter with dileptons  

Energy Technology Data Exchange (ETDEWEB)

Dileptons are shown to be of interest in helping probe extreme conditions of temperature and density in nuclear matter. The current state of experimental knowledge about dileptons is briefly described, and their use in upcoming experiments with light ions at CERN SPS are reviewed, including possible signatures of quark matter formation. Use of dileptons in an upcoming experiment with a new spectrometer at Berkeley is also discussed. This experiment will probe the nuclear matter equation of state at high temperature and density. 16 refs., 8 figs. (LEW)

Schroeder, L.S.

1986-06-01

109

Probing nuclear matter with dileptons  

International Nuclear Information System (INIS)

Dileptons are shown to be of interest in helping probe extreme conditions of temperature and density in nuclear matter. The current state of experimental knowledge about dileptons is briefly described, and their use in upcoming experiments with light ions at CERN SPS are reviewed, including possible signatures of quark matter formation. Use of dileptons in an upcoming experiment with a new spectrometer at Berkeley is also discussed. This experiment will probe the nuclear matter equation of state at high temperature and density. 16 refs., 8 figs.

1986-01-01

110

Flavor and Collider Signatures of Asymmetric Dark Matter  

CERN Multimedia

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

2013-01-01

111

Hot nuclear matter  

International Nuclear Information System (INIS)

The goal in this thesis is thus twofold: The first is to investigate the feasibility of using heavy ion collisions to create conditions in the laboratory which are ripe for the formation of a quark-gluon plasma. The second is to develop a technique for studying some of the many non-perturbative features of this novel phase of matter

1992-01-01

112

Nucleon in Nuclear Matter  

Directory of Open Access Journals (Sweden)

Full Text Available The modification of the properties of nucleon in nuclear medium has been investigated in the context of flux tube model. A nucleon has been described as diquark-quark system connected by flux tube and quasi particle diquark model has been used to describe the diquak constituting the nucleon. The modification of incompressiblity, the Roper resonance etc in the nuclear medium have been investigated. The results are compared with recent experimental and theoretical predictions. Some interesting observations are made.

Aparajita Bhattacharya; A. Sagari; B. Chakrabarti; A. Chandra

2011-01-01

113

Isospin constraints on the parametric coupling model for nuclear matter  

International Nuclear Information System (INIS)

We make use of isospin constraints to study the parametric coupling model and the properties of asymmetric nuclear matter. Besides the usual constraints for nuclear matter - the effective nucleon mass and the incompressibility at saturation density - and the neutron star constraints - maximum mass and radius - we study the properties related to the symmetry energy. These properties constrain the parameters of the model to a small range. We apply our results to study thermodynamic instabilities in the liquid-gas phase transition as well as neutron star configurations.

2010-01-01

114

Kaons in nuclear matter  

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

115

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

116

Instability in relativistic nuclear matter  

International Nuclear Information System (INIS)

The stability of the Fermi gas state in the nuclear matter which satisfies the saturation property is considered relativistically. It is shown that the Fermi gas state is stable at very low density and at high density, but it is unstable for density fluctuation in the intermediate density region including the normal density. (author)

1979-01-01

117

Constraining Asymmetric Bosonic Non-interacting Dark Matter with Neutron Stars  

CERN Multimedia

The Hawking evaporation of small black holes formed by the collapse of dark matter at the center of neutron stars plays a key role in loosing the constraint on the mass of asymmetric bosonic non-interacting dark matter particles. Different from previous works we show that such a kind of dark matter is viable in the mass range from 3.3 GeV to ~ 10 TeV, which covers the most attractive regions, including the preferred asymmetric dark matter mass ~ 5.7 GeV as well as the 5-15 GeV range favored by DAMA and CoGeNT.

Fan, Yi-zhong; Chang, Jin

2012-01-01

118

Dynamical simulation of expanding nuclear matter  

Energy Technology Data Exchange (ETDEWEB)

We study the properties of nuclear matter expanding dynamically using QMD model. For this purpose we developed an extended periodic boundary condition prescription. To calculate EOS of the expanding nuclear matter, the liquid-gas phase transition is discussed. (author)

Chikazumi, Shinpei [Tsukuba Univ., Tsukuba, Ibaraki (Japan); Maruyama, Toshiki; Iwamoto, Akira

1999-08-01

119

Kaon polarization in nuclear matter  

International Nuclear Information System (INIS)

The kaon-nucleon interaction in nuclear matter is considered by taking into account tree graphs, p-wave interaction, pionic intermediate states, kaon fluctuations and some residual interaction. The latter one is constrained by Adler's consistency condition. The K-, K+, K0, anti K0 polarization operators are calculated in cold nuclear matter with arbitrary isotopic composition. An extra s-wave repulsion is found, which probably shifts the critical point of a K- condensation with vanishing kaon momentum to large nucleon densities. Oppositely, an extra p-wave attraction is obtained, which may lead to a K- condensation at vanishing temperatures and densities ???c-?(4-6)?0. The spectrum of the kaonic excitations in nuclear matter is analyzed and a new low-lying branch in the K- (and also anti K0) spectrum is found. Its presence may lead to interesting observable consequences, such as the enhancement of the K- yields in heavy-ion reactions. At ???c- the frequency of this low-lying branch becomes negative at non-vanishing momentum; that signals the onset of inhomogeneous K-condensation. The K- condensate energy is calculated in the approximation of a small KK coupling constant. Accordingly, neutron matter may undergo ater with K- condensate at ?>?c-. The temperature dependence of the most important terms of the K- polarization operator is discussed. In a rather wide temperature region 0?/2 a growing temperature enlarges the K-N attraction and promotes the kaon condensation. The possibility of anti K0 condensation is also considered. The question is qualitatively discussed whether proton matter with K- condensate or neutron matter with anti K0 condensate is energetically more favorable. (orig.).

1994-01-01

120

Quark description of nuclear matter  

Energy Technology Data Exchange (ETDEWEB)

We discuss the role of an adjoint chiral condensate for color superconducting quark matter. Its presence leads to color-flavor locking in two-flavor quark matter. Color is broken completely as well as chiral symmetry in the two-flavor theory with coexisting adjoint quark-antiquark and antitriplet quark-quark condensates. The qualitative properties of this phase match the properties of ordinary nuclear matter without strange baryons. This complements earlier proposals by Schaefer and Wilczek for a quark description of hadronic phases. We show for a class of models with effective four-fermion interactions that adjoint chiral and diquark condensates do not compete, in the sense that simultaneous condensation occurs for sufficiently strong interactions in the adjoint chiral channel.

Berges, Jurgen

2001-07-01

 
 
 
 
121

Metastable formations of nuclear matter  

Energy Technology Data Exchange (ETDEWEB)

The dependence of the binding energy of nuclei on the mass number A is studied under the assumption that there is a negative pion condensate in continuous nuclear matter. It is shown that only nuclei with A ranging from A0 to one million are unstable. For A greater than one million they are metastable. A0 is the mass number of the most stable nucleus in a plasma. The spontaneous breakup of such nuclei is effectively ruled out. They can decay only in nuclear collisions or when the plasma temperature reaches values of 600 million.

Grigorian, L.Sh.; Saakian, G.S.

1980-10-01

122

Reflection-asymmetric nuclear deformations within the Density Functional Theory  

CERN Multimedia

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

123

Response function of nuclear matter  

Energy Technology Data Exchange (ETDEWEB)

We propose a new method to calculate the particle-hole Green's function for an infinite system of fermions in the long-wavelength limit of the random-phase approximation. Contrary to the standard approach the present method does not require approximating the residual particle-hole interaction by a sum of separable terms. The method can also be applied to the Landau theory of Fermi liquids. We illustrate the method by evaluating the response function of nuclear matter in the long-wavelength limit for two different isospin channels.

Dellafiore, A.; Matera, F.

1988-09-01

124

Three-body Force Effects on the Properties of Neutron-rich Nuclear Matter  

CERN Document Server

We review our research work on the single-particle properties and the equation of state (EOS) of isospin asymmetric nuclear matter within the framework of the Brueckner-Hartree-Fock (BHF) approach extended by including a microscopic three-body force (TBF). The TBF 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. The TBF-induced rearrangement effect and the ground state (g.s.) correlation effect on the s.p. properties in neutron-rich nuclear matter are investigated. Both effects turn out to be crucial for predicting reliably the s.p. properties within the Brueckner framework. The TBF effect on nucleon superfluidity in neutron star matter and neutron stars has also been discussed.

Zuo, Wei

2013-01-01

125

Asymmetric Circumstellar Matter in Type Ia Supernova Remnants  

Science.gov (United States)

The progenitors of Type Ia supernovae (SNe) are not well understood, but are likely to be of diverse origin, including single- and double-degenerate binary systems. Among single-degenerate progenitors, substantial amounts of circumstellar material (CSM) are expelled prior to the SN explosions by asymptotic giant branch (AGB) companions to the accreting white dwarfs. A subsequent collision of SN ejecta with the dense AGB wind has been detected among several distant SNe such as SN 2002ic, SN 2008J, and more recently PTF11kx. Dense CSM ejected by an AGB companion is present in the remnant of Kepler's SN of 1604, a Type Ia event. Observations of distant SNe hint at strongly asymmetric CSM distributions. A recent study of the CSM in Kepler's SNR by Burkey et al. indicates a large (factor of 10) density contrast between the dense, disk-like equatorial outflow and the more tenuous AGB wind above the orbital plane. A significant fraction of mature Type Ia SNRs in the Large Magellanic Cloud (LMC) shows the presence of dense Fe-rich ejecta in their interiors that cannot be explained by standard models of Type Ia explosions in a uniform ambient interstellar medium. We explore the hypothesis that these remnants originated in Type Ia explosions with strongly asymmetric CSM distributions such as found in Kepler's SNR. We present results of 2-D hydrodynamical simulations of the interaction of SN ejecta with asymmetric, disk-like AGB winds throughout the whole adiabatic stage of SNR evolution. Dense, asymmetric, and highly-ionized Fe-rich ejecta are indeed present in the simulated remnants, while the blast wave assumes a spherical shape shortly after passage through the ambient CSM. We also present simulated X-ray images and spectra and compare them with X-ray observations of selected remnants in the LMC. These remnants include DEM L238 and L249, recently observed by Suzaku, whose X-ray emission is strongly dominated by dense Fe-rich ejecta in their interiors. We contrast these remnants to more typical mature Type Ia SNRs such as 0534-69.9 and 0548-70.4 whose Suzaku spectra can be satisfactorily modeled with standard (without any CSM) X-ray models for Type Ia SNRs.

Borkowski, Kazimierz J.; Reynolds, S. P.; Blondin, J. M.

2013-01-01

126

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

CERN Document Server

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

127

Latent heat of nuclear matter  

CERN Multimedia

We study the latent heat of the liquid-gas phase transition in symmetric nuclear matter using self-consistent mean-field calculations with a few Skyrme forces. The temperature dependence of the latent heat is rather independent of the mean-field parametrization and can be characterized by a few parameters. At low temperatures, the latent heat tends to the saturation energy. Near the critical point, the latent heat goes to zero with a well-determined mean-field critical exponent. A maximum value of the latent heat in the range l ~ 25-30 MeV is found at intermediate temperatures, which might have experimental relevance. All these features can be explained from very basic principles.

Carbone, Arianna; Rios, Arnau; Vidaña, Isaac

2010-01-01

128

Interfering Composite Asymmetric Dark Matter for DAMA and CoGeNT  

CERN Multimedia

We provide a simple mechanism for reconciling the direct dark matter experimental results. We consider light asymmetric composite dark matter which scatters off nuclei via Higgs and photon exchange. We demonstrate that the interference between these two channels naturally accommodates the experimental results. We discover that this happens for a compositeness scale of the order of the electroweak. We also provide a model realization based on strong dynamics at the electroweak scale.

Del Nobile, Eugenio; Sannino, Francesco

2011-01-01

129

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

130

Charge asymmetric cosmic ray signals from dark matter decay  

International Nuclear Information System (INIS)

The PAMELA and Fermi measurements of the cosmic ray electron and positron spectra have generated much interest over the past two years, because they are consistent with a significant component of the electron and positron fluxes between 20 GeV and 1 TeV being produced through dark matter annihilation or decay. However, since the measurements are also consistent with astrophysical interpretations, the message is unclear. In this paper, we point out that dark matter can have a more distinct signal in cosmic rays, that of a charge asymmetry. Such charge asymmetry can result if the dark matter's abundance is due to a relic asymmetry, allowing its decay to generate an asymmetry in positrons and electrons. This is analogous to the baryon asymmetry, where decaying neutrons produce electrons and not positrons. We explore benchmark scenarios where the dark matter decays into a leptophilic charged Higgs boson or electroweak gauge bosons. These models have observable signals in gamma rays and neutrinos, which can be tested by Fermi and IceCube. The most powerful test will be at AMS-02, given its ability to distinguish electron and positron charge above 100 GeV. Specifically, an asymmetry favoring positrons typically predicts a larger positron ratio and a harder (softer) high energy spectrum for positrons (electrons) than charge symmetric sources. We end with a brief discussion on how such scenarios differ from the leading astrophysical explanations.

2011-07-15

131

Asymmetric dark matter from spontaneous cogenesis in the supersymmetric standard model  

International Nuclear Information System (INIS)

The observational relation between the density of baryon and dark matter in the Universe, ?DM/?B?5, is one of the most difficult problems to solve in modern cosmology. We discuss a scenario that explains this relation by combining the asymmetric dark matter scenario and the spontaneous baryogenesis associated with the flat direction in the supersymmetric standard model. A part of baryon asymmetry is transferred to charge asymmetry D that dark matter carries, if a symmetry violating interaction that works at high temperature breaks not only B-L but also D symmetries simultaneously. In this case, the present number density of baryon and dark matter can be same order if the symmetric part of dark matter annihilates sufficiently. Moreover, the baryon number density can be enhanced as compared to that of dark matter if another B-L violating interaction is still in thermal equilibrium after the spontaneous genesis of dark matter, which accommodates a TeV scale asymmetric dark matter model. (orig.)

2012-01-01

132

Asymmetric dark matter from spontaneous cogenesis in the supersymmetric standard model  

Energy Technology Data Exchange (ETDEWEB)

The observational relation between the density of baryon and dark matter in the Universe, {omega}{sub DM}/{omega}{sub B}{approx_equal}5, is one of the most difficult problems to solve in modern cosmology. We discuss a scenario that explains this relation by combining the asymmetric dark matter scenario and the spontaneous baryogenesis associated with the flat direction in the supersymmetric standard model. A part of baryon asymmetry is transferred to charge asymmetry D that dark matter carries, if a symmetry violating interaction that works at high temperature breaks not only B-L but also D symmetries simultaneously. In this case, the present number density of baryon and dark matter can be same order if the symmetric part of dark matter annihilates sufficiently. Moreover, the baryon number density can be enhanced as compared to that of dark matter if another B-L violating interaction is still in thermal equilibrium after the spontaneous genesis of dark matter, which accommodates a TeV scale asymmetric dark matter model. (orig.)

Kamada, Kohei [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Yamaguchi, Masahide [Tokyo Institute of Technology (Japan). Dept. of Physics

2012-01-15

133

Simple effective interaction: Infinite nuclear matter and finite nuclei  

CERN Document Server

The mean field properties and equation of state for asymmetric nuclear matter are studied by using a simple effective interaction which has a single finite range Gaussian term. The study of finite nuclei with this effective interaction is done by means of constructing a quasilocal energy density functional for which the single particle equations take the form of Skryme-Hartree-Fock equations. The predictions of binding energies and charge radii of spherical nuclei are found to be compatible with the results of standard models as well as experimental data.

Behera, B; Bhuyan, M; Routray, T R; Sharma, B K; Patra, S K

2013-01-01

134

Light asymmetric dark matter from new strong dynamics  

DEFF Research Database (Denmark)

A ~5 GeV `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 Toudal; Sarkar, Subir

2011-01-01

135

Nuclear Matter in Relativistic Mean Field Theory with Isovector Scalar Meson  

CERN Multimedia

Relativistic mean field (RMF) theory of nuclear matter with the isovector scalar mean field corresponding to the delta-meson [a_0(980)] is studied. While the delta-meson mean field vanishes in symmetric nuclear matter, it can influence properties of asymmetric nuclear matter in neutron stars. The RMF contribution due to delta-field to the nuclear symmetry energy is negative. To fit the empirical value, E_s=30 MeV, a stronger rho-meson coupling is required than in the absence of the delta-field. The energy per particle of neutron matter is then larger at high densities than the one with no delta-field included. Also, the proton fraction of beta-stable matter increases. Splitting of proton and neutron effective masses due to the delta-field can affect transport properties of neutron star matter.

Kubis, S

1997-01-01

136

Nuclear and neutron matter studies  

Energy Technology Data Exchange (ETDEWEB)

We are studying nuclear and neutron matter with the new Argonne v{sub 18} NN and Urbana 3N potentials. We use variational wave functions and a diagrammatic cluster expansion with Fermi hypernetted and single-operator chain (FHNC/SOC) integral equations to evaluate the energy expectation value. Initial results show some interesting differences with our previous calculations with the older Argonne v{sub 14} potential. In particular, there are a number of diagrams involving L{center_dot}S and L{sup 2} terms which were small with the older model and were rather crudely estimated or even neglected. It appears that these terms are more important with the new potential and will have to be evaluated more accurately. Work on this subject is in progress. A simple line of attack is to just add additional diagrams at the three-body cluster level. A longer term approach may be to adapt some of the methods for evaluating nucleon clusters used in the few-body and closed shell nuclei described above.

Wiringa, R.B.; Akmal, A.; Pandharipande, V.R.

1995-08-01

137

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

138

Soliton matter as a model of dense nuclear matter  

Energy Technology Data Exchange (ETDEWEB)

We employ the hybrid soliton model of the nucleon consisting of a topological meson field and deeply bound quarks to investigate the behavior of the quarks in soliton matter as a function of density. To organize the calculation, we place the solitons on a spatial lattice. The model suggests the transition of matter from a color insulator to a color conductor above a critical density of a few times normal nuclear density. 9 references, 5 figures.

Glendenning, N.K.

1985-01-01

139

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

140

Chiral mesons in dense nuclear matter  

Energy Technology Data Exchange (ETDEWEB)

Chiral symmetry restoration together with the sigma- and pi-meson propagators are calculated in dense baryonic matter. The vacuum is described by a Nambu-Jona-Lasinio model of quarks. Nuclear matter is described by a Fermi sea of either quarks or nucleons. The two descriptions are found to give different results for chiral symmetry restoration at high densities. (orig.).

Jaminon, M.; Stassart, P. (Liege Univ. (Belgium). Inst. de Physique); Ripka, G. (CEA Centre d' Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France). Service de Physique Theorique)

1989-11-27

 
 
 
 
141

Chiral mesons in dense nuclear matter  

International Nuclear Information System (INIS)

Chiral symmetry restoration together with the ?- and ?-meson propagators are calculated in dense baryonic matter. The vacuum is described by a Nambu-Jona-Lasinio model of quarks. Nuclear matter is described by a Fermi sea of either quarks or nucleons. The two descriptions are found to give different results for chiral symmetry restoration at high densities. (orig.)

1989-11-27

142

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

143

Coupled Cluster studies of infinite nuclear matter  

CERN Document Server

The aim of this work is to develop the relevant formalism for performing Coupled Cluster 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 the exact treatment of the so-called Pauli operator in a partial wave expansion of the equation of state. 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 non-linear diagrams from the CC doubles amplitude equation. This study is a first step toward CC calculations for nuclear and neutron matter. 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 [A. E...

Baardsen, G; Hagen, G; Hjorth-Jensen, M

2013-01-01

144

Dark matter studies entrain nuclear physics  

Science.gov (United States)

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; Fuller, George M.

2013-07-01

145

Relativity damps OPEP in nuclear matter  

Energy Technology Data Exchange (ETDEWEB)

Using a relativistic Dirac-Brueckner analysis the OPEP contribution to the ground state energy of nuclear matter is studied. In the study the pion is derivative-coupled. The author finds that the role of the tensor force in the saturation mechanism is substantially reduced compared to its dominant role in a usual nonrelativistic treatment. He shows that the damping of derivative-coupled OPEP is actually due to the decrease of M{sup *}/M with increasing density. He points out that if derivative-coupled OPEP is the preferred form of nuclear effective lagrangian nonrelativistic treatment of nuclear matter is in trouble. Lacking the notion of M{sup *} it cannot replicate the damping. He suggests an examination of the feasibility of using pseudoscalar coupled {pi}N interaction before reaching a final conclusion about nonrelativistic treatment of nuclear matter.

Banerjee, M.K.

1998-06-01

146

Relativity damps OPEP in nuclear matter  

International Nuclear Information System (INIS)

Using a relativistic Dirac-Brueckner analysis the OPEP contribution to the ground state energy of nuclear matter is studied. In the study the pion is derivative-coupled. The author finds that the role of the tensor force in the saturation mechanism is substantially reduced compared to its dominant role in a usual nonrelativistic treatment. He shows that the damping of derivative-coupled OPEP is actually due to the decrease of M*/M with increasing density. He points out that if derivative-coupled OPEP is the preferred form of nuclear effective lagrangian nonrelativistic treatment of nuclear matter is in trouble. Lacking the notion of M* it cannot replicate the damping. He suggests an examination of the feasibility of using pseudoscalar coupled ?N interaction before reaching a final conclusion about nonrelativistic treatment of nuclear matter

1998-01-01

147

Instrumentation for controlling nuclear matters  

International Nuclear Information System (INIS)

After a brief recall of nuclear properties of fissile materials, the author gives examples of radiation detectors used in France for detecting movements of plutonium and uranium. The detection is made either by gamma detection or by neutron detection

1987-01-01

148

Hadronization in cold nuclear matter  

CERN Multimedia

I review a recently proposed scaling analysis of hadron suppression in Deeply Inelastic Scattering on nuclear targets measured at the HERMES experiment. The analysis can distinguish 2 competing explanations for the observed suppression, namely, quark radiative energy loss with long hadron formation times, and prehadron nuclear absorption with hadronization starting inside the nucleus. Experimental data are shown to favor short formation times and prehadron absorption.

Accardi, A

2007-01-01

149

The exploration of hot nuclear matter.  

UK PubMed Central (United Kingdom)

When nuclear matter is heated beyond 2 trillion degrees, it becomes a strongly coupled plasma of quarks and gluons. Experiments using highly energetic collisions between heavy nuclei have revealed that this new state of matter is a nearly ideal, highly opaque liquid. A description based on string theory and black holes in five dimensions has made the quark-gluon plasma an archetypical strongly coupled quantum system. Open questions about the structure and theory of the quark-gluon plasma are under active investigation. Many of the insights are also relevant to ultracold fermionic atoms and strongly correlated condensed matter.

Jacak BV; Müller B

2012-07-01

150

Density fluctuations and multifragmentation of nuclear matter  

CERN Multimedia

The density fluctuations of nuclear matter are studied within a mean-field model in wich fluctuations are generated by an external stochastic field. The constraints imposed on the random force by the fluctuation-dissipation theorem are analyzed. It is shown that in the proximity of the borders of the spinodal region the assumption of a white-noise stochastic field can be reliably used. The domain distribution of the liquid phase in the spinodal decomposition of nuclear matter is derived. The related distribution of fragment sizes compares favourably with the experimental fragment distribution observed in heavy ion collisions.

Matera, F

2000-01-01

151

Localized Asymmetric Atomic Matter Waves in Two-Component Bose-Einstein Condensates Coupled with Two Photon Microwave Field  

CERN Multimedia

We investigate localized atomic matter waves in two-component Bose-Einstein condensates coupled by the two photon microwave field. Interestingly, the oscillations of localized atomic matter waves will gradually decay and finally become non-oscillating behavior even if existing coupling field. In particular, atom numbers occupied in two different hyperfine spin states will appear asymmetric occupations after some time evolution.

Xiong, B

2007-01-01

152

Charmonium mass in nuclear matter  

CERN Document Server

The charmed meson one-loop effect on the mass of psi(3770) in nuclear medium is studied in a hadronic model. Taking into account the reduced charmed meson in-medium mass as a result of the partial restoration of chiral symmetry, we find that the psi(3770) mass decreases appreciably at finite nuclear density. The result is compared with that from the perturbative QCD approach. The mass shifts of psi(3770) and other charmonium states could be observed in the experiments at the future accelerator facility at GSI.

Ko, C M; Lee, Su Houng

2003-01-01

153

Spin- and isospin-polarized states of nuclear matter in the Dirac-Brueckner-Hartree-Fock model  

CERN Multimedia

Spin-polarized isospin asymmetric nuclear matter is studied within the Dirac-Brueckner-Hartree-Fock approach. After a brief review of the formalism, we present and discuss the self-consistent single-particle potentials at various levels of spin and isospin asymmetry. We then move to predictions of the energy per particle, also under different conditions of isospin and spin polarization. Comparison with the energy per particle in isospin symmetric or asymmetric unpolarized nuclear matter shows no evidence for a phase transition to a spin ordered state, neither ferromagnetic nor antiferromagnetic.

Sammarruca, Francesca

2011-01-01

154

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

155

Nuclear fusion in dense matter.  

Science.gov (United States)

The standard theory of nuclear fusion rates in strongly interacting plasmas can be (correctly) derived only when the energy release Q is large compared to other energies in the problem. We exhibit a result for rates that provides a basis for calculating the finite Q corrections. Crude estimates indicate a significant defect in the conventional results for some regions of high density and strong plasma coupling. We also lay some groundwork for a path integral calculation of the new effects. PMID:20866957

Sawyer, R F

2010-05-14

156

Nuclear fusion in dense matter.  

UK PubMed Central (United Kingdom)

The standard theory of nuclear fusion rates in strongly interacting plasmas can be (correctly) derived only when the energy release Q is large compared to other energies in the problem. We exhibit a result for rates that provides a basis for calculating the finite Q corrections. Crude estimates indicate a significant defect in the conventional results for some regions of high density and strong plasma coupling. We also lay some groundwork for a path integral calculation of the new effects.

Sawyer RF

2010-05-01

157

Consequences of DM/antiDM Oscillations for Asymmetric WIMP Dark Matter  

CERN Document Server

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. 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; Servant, Geraldine; Zaharijas, Gabrijela

2012-01-01

158

Hadron-quark phase transition in asymmetric matter with boson condensation  

CERN Document Server

In the present work we study the hadron-quark phase transition with boson condensation in asymmetric matter by investigating the binodal surface and extending it to finite temperature in order to mimic the QCD phase diagram. We consider a system with two conserved charges (isospin and baryon densities) using the Gibbs' criteria for phase equilibrium. In order to obtain these conditions we use two different models for the two possible phases, namely the non-linear Walecka model (NLWM) for the hadron matter (also including hyperons) and the MIT bag model for the quark phase. It is shown that the phase transition is very sensitive to the density dependence of the equation of state and the symmetry energy. For isospin asymmetry of 0.2 and a mixed phase with a fraction of 20% of quarks, a transition density in the interval 2 rho_0 to 4 rho_0 was obtained for temperatures 30 < T < 65 MeV.

Cavagnoli, Rafael; Menezes, Debora P

2010-01-01

159

Anharmonicity of the nuclear matter ground state  

International Nuclear Information System (INIS)

The correlation between the compression modulus and the skewness coefficient of the nuclear matter ground state implied by the breathing mode data is compared with predictions of the relativistic Hartree approximation (RHA). Retaining explicit dependence on the renormalization scale, ?, employed in the RHA, this correlation, together with other considerations, suggests a value for ?/M?1.2. (orig.).

1992-01-01

160

Anharmonicity of the nuclear matter ground state  

Energy Technology Data Exchange (ETDEWEB)

The correlation between the compression modulus and the skewness coefficient of the nuclear matter ground state implied by the breathing mode data is compared with predictions of the relativistic Hartree approximation (RHA). Retaining explicit dependence on the renormalization scale, {mu}, employed in the RHA, this correlation, together with other considerations, suggests a value for {mu}/M{approx equal}1.2. (orig.).

Rudaz, S.; Ellis, P.J.; Heide, E.K. (School of Physics and Astronomy, Univ. Minnesota, Minneapolis, MN (United States)); Prakash, M. (Physics Dept., State Univ. of New York, Stony Brook, NY (United States))

1992-07-09

 
 
 
 
161

Condensed matter studies by nuclear methods  

International Nuclear Information System (INIS)

The separate abstract was prepared for 1 of the papers in this volume. The remaining 13 papers dealing with the use but not with advances in the use of nuclear methods in studies of condensed matter, were considered outside the subject scope of INIS. (M.F.W.)

1988-01-01

162

Spin-isospin stability of nuclear matter  

Science.gov (United States)

We calculate the density-dependent spin-isospin asymmetry energy J(kf) of nuclear matter in the three-loop approximation of chiral perturbation theory. The interaction contributions to J(kf) originate from one-pion exchange, iterated one-pion exchange, and irreducible two-pion exchange with no, single, and double virtual ?-isobar excitation. We find that the approximation to 1?-exchange and iterated 1?-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(kf0)?24MeV>0. The inclusion of the chiral ?N? dynamics, necessary in order to guarantee the spin stability of nuclear matter, keeps this property intact. The corresponding spin-isospin asymmetry energy J(kf) stays positive even for extreme values of an undetermined short-distance parameter J5 (whose possible range we estimate from realistic NN potentials). The largest positive contribution to J(kf) (a term linear in density) comes from a two-body contact term with its strength fitted to the empirical nuclear matter saturation point.

Kaiser, N.

2005-07-01

163

Probing Cold Dense Nuclear Matter  

International Nuclear Information System (INIS)

The protons and neutrons in a nucleus can form strongly correlated nucleon pairs. Scattering experiments, in which a proton is knocked out of the nucleus with high-momentum transfer and high missing momentum, show that in carbon-12 the neutron-proton pairs are nearly 20 times as prevalent as proton-proton pairs and, by inference, neutron-neutron pairs. This difference between the types of pairs is due to the nature of the strong force and has implications for understanding cold dense nuclear systems such as neutron stars.

2008-06-01

164

Probing Cold Dense Nuclear Matter  

CERN Document Server

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

165

Probing cold dense nuclear matter.  

UK PubMed Central (United Kingdom)

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 R; Shneor R; Monaghan P; Anderson BD; Aniol K; Annand J; Arrington J; Benaoum H; Benmokhtar F; Boeglin W; Chen JP; Choi S; Cisbani E; Craver B; Frullani S; Garibaldi F; Gilad S; Gilman R; Glamazdin O; Hansen JO; Higinbotham DW; Holmstrom T; Ibrahim H; Igarashi R; de Jager CW; Jans E; Jiang X; Kaufman LJ; Kelleher A; Kolarkar A; Kumbartzki G; Lerose JJ; Lindgren R; Liyanage N; Margaziotis DJ; Markowitz P; Marrone S; Mazouz M; Meekins D; Michaels R; Moffit B; Perdrisat CF; 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 GM; Voutier E; Watson JW; Weinstein LB; Wojtsekhowski B; Wood S; Zheng XC; Zhu L

2008-06-01

166

Probing cold dense nuclear matter.  

Science.gov (United States)

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

2008-05-29

167

NUCLEAR PHYSICS: Nucleon 3PF2 Superfluid Pairing Gap in Asymmetry Nuclear Matter  

Science.gov (United States)

The 3PF2 superfluidity of neutron and proton is investigated in isospin-asymmetric nuclear matter within the Brueckner-Hartree-Fock approach and the BCS theory by adopting the Argonne V14 and the Argonne V18 nucleon-nucleon interactions. We find that pairing gaps in the 3PF2 channel predicted by adopting the AV14 interaction are much larger than those by the AV18 interaction. As the isospin-asymmetry increases, the neutron 3PF2 superfluidity is found to increase rapidly, whereas the proton one turns out to decrease and may even vanish at high enough asymmetries. As a consequence, the neutron 3PF2 superfluidity is much stronger than the proton one at high asymmetries and it predominates over the proton one in dense neutron-rich matter.

Mi, Ai-Jun; Zuo, Wei; Li, Zeng-Hua; Lombardo, Umberto

2009-06-01

168

Probing Nuclear Matter with Jet Conversions  

CERN Multimedia

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

169

From QCD to nuclear matter saturation  

International Nuclear Information System (INIS)

We discuss a relativistic chiral theory of nuclear matter with ? and ? exchange using a formulation of the ? model in which all the chiral constraints are automatically fulfilled. We establish a relation between the nuclear response to the scalar field and the QCD one which includes the nucleonic parts. It allows a comparison between nuclear and QCD information. Going beyond the mean field approach we introduce the effects of the pion loops supplemented by the short-range interaction. The corresponding Landau-Migdal parameters are taken from spin-isospin physics results. The parameters linked to the scalar meson exchange are extracted from lattice QCD results. These inputs lead to a reasonable description of the saturation properties, illustrating the link between QCD and nuclear physics. We also derive from the corresponding equation of state the density dependence of the quark condensate and of the QCD susceptibilities. (author)

2007-12-08

170

From QCD to nuclear matter saturation  

Energy Technology Data Exchange (ETDEWEB)

We discuss a relativistic chiral theory of nuclear matter with {sigma} and {omega} exchange using a formulation of the {sigma} model in which all the chiral constraints are automatically fulfilled. We establish a relation between the nuclear response to the scalar field and the QCD one which includes the nucleonic parts. It allows a comparison between nuclear and QCD information. Going beyond the mean field approach we introduce the effects of the pion loops supplemented by the short-range interaction. The corresponding Landau-Migdal parameters are taken from spin-isospin physics results. The parameters linked to the scalar meson exchange are extracted from lattice QCD results. These inputs lead to a reasonable description of the saturation properties, illustrating the link between QCD and nuclear physics. We also derive from the corresponding equation of state the density dependence of the quark condensate and of the QCD susceptibilities. (authors)

Ericson, Magda [Universite de Lyon, Univ. Lyon 1, CNRS/IN2P3, IPN Lyon, F-69622 Villeurbanne Cedex (France)]|[Theory division, CERN, CH-12111 Geneva (Switzerland); Chanfray, Guy [Universite de Lyon, Univ. Lyon 1, CNRS/IN2P3, IPN Lyon, F-69622 Villeurbanne Cedex (France)

2007-03-15

171

From QCD to nuclear matter saturation  

International Nuclear Information System (INIS)

We discuss a relativistic chiral theory of nuclear matter with ? and ? exchange using a formulation of the ? model in which all the chiral constraints are automatically fulfilled. We establish a relation between the nuclear response to the scalar field and the QCD one which includes the nucleonic parts. It allows a comparison between nuclear and QCD information. Going beyond the mean field approach we introduce the effects of the pion loops supplemented by the short-range interaction. The corresponding Landau-Migdal parameters are taken from spin-isospin physics results. The parameters linked to the scalar meson exchange are extracted from lattice QCD results. These inputs lead to a reasonable description of the saturation properties, illustrating the link between QCD and nuclear physics. We also derive from the corresponding equation of state the density dependence of the quark condensate and of the QCD susceptibilities. (authors)

2007-01-01

172

Approach to deconfinement in dense nuclear matter  

CERN Multimedia

We describe an analytic method to investigate the change in nuclear matter as its density rises. It consists in studying the density dependence of the residue of the nucleon pole in the two-point correlation function of nucleon currents by writing a QCD sum rule for it. The nucleon self-energy needed for the sum rule is taken as input from calculations using phenomenological N-N potential. Our result shows a decrease in the residue with increasing nuclear density, signalling the approach to a deconfined phase.

Mallik, S

2009-01-01

173

Light Vector Mesons In Nuclear Matter  

UK PubMed Central (United Kingdom)

We summarize the current theoretical and experimental status of the spectralchanges of vector mesons (ae, !, OE) in nuclear medium. Various approaches includingQCD sum rules, effective theory of hadrons and bag models show decreasing of thevector meson masses in nuclear matter. Possibility to detect the mass shift throughlepton pairs in fl Gamma A, p Gamma A and A Gamma A reactions are also discussed.Invited paper submitted to Prog. Theor. Phys.1 IntroductionAt high temperature (T ) and density (ae), hadronic matter is expected to undergoa phase transition to the quark-gluon plasma [1]. The order parameter characterizingthe transition is the chiral quark condensate h¯qqi, the absolute value ofwhich decreases as (T ,ae) increases. Numerical simulations of quantum chromodynamics(QCD) on the lattice are actively pursued to determine the precisenature of the transition at finite T [2] and various model calculations have beendone to look for the observable signature of th...

T. Hatsuda; H. Shiomi

174

Nuclear matter within the continuous choice  

Energy Technology Data Exchange (ETDEWEB)

The saturation curve of symmetric nuclear matter is calculated at the Brueckner-Hartree-Fock level of approximation within the continuous choice for the single-particle potential. The realistic local Argonne {ital v}{sub 14} potential is used and the results are compared with similar calculations presented in the literature. The binding energies per nucleon around saturation agree closely with previous results obtained with separable versions of the same potential as well as of the Paris potential.

Baldo, M.; Bombaci, I.; Ferreira, L.S.; Giansiracusa, G.; Lombardo, U. (Instituto Nazionale di Fisica Nucleare, Sezione di Catania, Corso Italia 57, 95129 Catania, Italy (IT) Dipartimento di Fisica, Universita di Catania, Corso Italia 57, 95129 Catania, Italy)

1991-06-01

175

Nuclear matter within the continuous choice  

International Nuclear Information System (INIS)

[en] The saturation curve of symmetric nuclear matter is calculated at the Brueckner-Hartree-Fock level of approximation within the continuous choice for the single-particle potential. The realistic local Argonne v14 potential is used and the results are compared with similar calculations presented in the literature. The binding energies per nucleon around saturation agree closely with previous results obtained with separable versions of the same potential as well as of the Paris potential

1991-01-01

176

Cold Nuclear Matter In Holographic QCD  

CERN Multimedia

We study the Sakai-Sugimoto model of holographic QCD at zero temperature and finite chemical potential. We find that as the baryon chemical potential is increased above a critical value, there is a phase transition to a nuclear matter phase characterized by a condensate of instantons on the probe D-branes in the string theory dual. As a result of electrostatic interactions between the instantons, this condensate expands towards the UV when the chemical potential is increased, giving a holographic version of the expansion of the Fermi surface. We argue based on properties of instantons that the nuclear matter phase is necessarily inhomogeneous to arbitrarily high density. This suggests an explanation of the ``chiral density wave'' instability of the quark Fermi surface in large N_c QCD at asymptotically large chemical potential. We study properties of the nuclear matter phase as a function of chemical potential beyond the transition and argue in particular that the model can be used to make a semi-quantitative...

Rozali, Moshe; Van Raamsdonk, Mark; Wu, Jackson

2008-01-01

177

A Naturally Light Sterile neutrino in an Asymmetric Dark Matter Model  

CERN Multimedia

A recently proposed asymmetric mirror dark matter model where the mirror sector is connected with the visible one by a right handed neutrino portal, is shown to lead naturally to a 3+1 active-sterile neutrino spectrum, if the portal consists only of two right handed neutrinos. At the tree level the model has four massless neutrino states, three active and one sterile. The active neutrinos pick up tiny masses via the minimal radiative inverse seesaw mechanism at the one loop level. The loop effects also generate the large solar and atmospheric mixings, as well as the observed reactor mixing for certain range of parameters of the model. The dominant contribution to the sterile neutrino mass ($\\sim$ eV) arises from the gravitationally induced dimension-5 operators. Generating active-sterile mixing requires a two Higgs doublet extension of SM and a small mixing between the ordinary and mirror Higgs fields, which occurs naturally in mirror models.

Zhang, Yongchao; Mohapatra, Rabindra N

2013-01-01

178

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

179

Properties of the cloudy bag in the nuclear matter  

International Nuclear Information System (INIS)

Because of the pion mode softening, the pion field of the cloudy bag in the nuclear matter increases if the nuclear matter density increases. This causes in its term the decreasing of the bag size and at a sufficiently large density of the nuclear medium leads to the absolute instability of the cloudy bag-nucleon, which means the transition of the nuclear matter in another nonnucleon phase.

1984-01-01

180

Chiral quark dynamics in dense nuclear matter  

CERN Document Server

We consider a new approach to the description of dense nuclear matter in the framework of chirally symmetric, quark-based hadron models. As previously in the Skyrme model, the dense environment is described in terms of hyperspherical cells of unit baryon number. The intrinsic curvature of these cells generates a new gauge interaction for the quark fields which mediates interactions with the ambient matter. We apply this approach to the Nambu-Jona-Lasinio (NJL) model, construct its curved-space quark propagator and solve the ladder Bethe-Salpeter equation for the pion. We find a high-density phase transition to chiral restoration, discuss the density dependence of the chiral order parameter and of the pion properties, and compare with results of the conventional chemical-potential approach. The new approach can additionally describe baryon-density-free cavities in the dense medium.

Forkel, H

1995-01-01

 
 
 
 
181

Electrostrong Nuclear Disintegration in Condensed Matter  

CERN Multimedia

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

182

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

183

Nucleon sigma term and quark condensate in nuclear matter  

Energy Technology Data Exchange (ETDEWEB)

We study the bound nucleon sigma term and its effect on the quark condensate in nuclear matter. In the quark-meson coupling (QMC) model it is shown that the nuclear correction to the sigma term is small and negative. Thus, the correction decelerates the decrease of the quark condensate in nuclear matter. However, the quark condensate in nuclear matter is controlled primarily by the scalar-isoscalar sigma field of the model. It appreciably moderates the decrease relative to the leading term at densities around and larger than the normal nuclear matter density.

K. Tsushima; K. Saito; A. W. Thomas; A. Valcarce

2007-03-01

184

Response function of hot nuclear matter  

International Nuclear Information System (INIS)

The response function of hot nuclear matter to a small isovector external field is investigated. It is shown that for a simplified Skyrme interaction an analytical and self-consistent formula can be derived. An interesting feature of this formula is that it exhibits a privileged value of the interaction strength beyond which a rapid variation of the dipole strength with temperature is obtained. It is concluded that available data for the thermal evolution of giant resonances provide valuable information on the particle-hole effective interaction. (authors). 14 refs., 2 figs.

1994-01-01

185

Nuclear interaction rates for dark matter detectors  

International Nuclear Information System (INIS)

[en] I describe nuclear shell model calculations of the spin-dependent elastic cross sections of supersymmetric particles on the nuclei 73Ge and 29Si, which are being used in the construction of dark matter detectors. To check the accuracy of the wave functions I have calculated excited state energy spectra, magnetic moments, and spectroscopic factors for each of the nuclei. Our results differ significantly from previous estimates based upon the independent single particle shell model and the odd group model. I at% discuss the modifications that occur when finite momentum transfer between the neutralino and nucleus is included

1992-01-01

186

Chiral Symmetry, Strangeness and Nuclear Matter  

International Nuclear Information System (INIS)

[en] In this talk we review the important role played by chiral SU(3) symmetry in hadron physics. Exciting new results on the formation of baryon resonances as implied by chiral coupled-channel dynamics are presented and discussed. The results are the consequence of progress made in formulating a consistent effective field theory for the meson-baryon scattering processes in the resonance region. Strangeness channels are found to play a decisive role in the formation of resonances. As a further application of chiral coupled-channel dynamics the properties of antikaons and hyperon resonances in cold nuclear matter are reviewed. (author)

2003-09-07

187

Pion condensation in symmetric nuclear matter  

Energy Technology Data Exchange (ETDEWEB)

We have investigated the possibility of pion condensation in symmetric nuclear matter using a model of pion-nucleon interaction based essentially on chiral SU(2) x SU(2) symmetry. We have found that pion condensation is not possible for any finite value of the density. Consequently, no critical opalescence phenomenon is likely to be seen in pion-nucleus scattering nor is it likely to be possible to explain the EMC effect in terms of an increased number of pions in the nucleus. (author).

Shamsunnahar, T.; Saha, S.; Kabir, K.; Nath, L.M. (Dacca Univ. (Bangladesh). Dept. of Physics)

1991-06-01

188

Fast hadron energy losses by excitation of nuclear matter  

International Nuclear Information System (INIS)

[en] A concept of deep inelastic hadron-nuclear reactions as a series of local interactions of a fast hadron with nuclear matter permits to introduce a notion of hadron specific energy losses by nuclear matter excitation. Due to nuclear scaling this value does not depend on the energy and type of an incident particle. The estimations made on the basis of experimental data on inclusive particle spectra in the nuclear fragmentation range, as well as regularities of approximation to limiting fragmentation for different nuclei lead to the value of hadron specific energy losses in the nuclear matter of about 1 GeV/fm

1986-01-01

189

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

International Nuclear Information System (INIS)

[en] 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

190

Isospin dependence of nuclear matter symmetry energy coefficients  

CERN Multimedia

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 isospin and scalar channels. The use of Skyrme-type effective forces allows us to obtain analytical expressions for these parameters as well as their dependences on the neutron-proton (n-p) asymmetry, density and even temperature. Whereas the density dependence of these coefficients obtained with Skyrme forces is not necessarily realistic the dependence on the n-p asymmetry exhibit a more consistent behaviour. The isospin symmetry energy coefficient (s.e.c.) increases as the n-p asymmetry acquires higher values whereas the isoscalar s.e.c. d...

Braghin, F L

2001-01-01

191

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; Hesham Mansour

2013-01-01

192

Ground-state energy of nuclear matter  

Energy Technology Data Exchange (ETDEWEB)

The low-density expansion of the ground-state energy for spin-dependent forces is given, through order k/sub F//sup 6/ for the ladder approximation and through order k/sub F//sup 6/lnk/sub F/ for the complete energy, in terms of derivatives with respect to the strength of the attractive part of the interaction defined by the Baker-Hind-Kahane potential. The ladder approximation is also computed by the numerical solution of the K-matrix equation. The resulting series gives a satisfactory representation of the energy at interesting densities. Using Pade extrapolation techniques, both in the density and in the attractive part of the interaction, we obtain the ground-state energy of nuclear matter.

Baker G.A. Jr.; Benofy, L.P.; Fortes, M.

1988-07-01

193

Relativistic Approach to Superfluidity in Nuclear Matter  

CERN Document Server

Pairing correlations in symmetric nuclear matter are studied within a relativistic mean-field approximation based on a field theory of nucleons coupled to neutral ($\\sigma$ and $\\omega$) and to charged ($\\varrho$) mesons. The Hartree-Fock and the pairing fields are calculated in a self-consistent way. The energy gap is the result of a strong cancellation between the scalar and vector components of the pairing field. We find that the pair amplitude vanishes beyond a certain value of momentum of the paired nucleons. This fact determines an effective cutoff in the gap equation. The value of this cutoff gives an energy gap in agreement with the estimates of non relativistic calculations.

Matera, F; Dellafiore, A

1997-01-01

194

Relativistic approach to superfluidity in nuclear matter  

International Nuclear Information System (INIS)

Pairing correlations in symmetric nuclear matter are studied within a relativistic mean-field approximation based on a field theory of nucleons coupled to neutral (? and ?) and to charged (?) mesons. The Hartree-Fock and the pairing fields are calculated in a self-consistent way. The energy gap is the result of a strong cancellation between the scalar and vector components of the pairing field. We find that the pair amplitude vanishes beyond a certain value of momentum of the paired nucleons. This fact determines an effective cutoff in the gap equation. The value of this cutoff gives an energy gap in agreement with the estimates of nonrelativistic calculations. copyright 1997 The American Physical Society.

1997-01-01

195

Relativistic approach to superfluidity in nuclear matter  

Energy Technology Data Exchange (ETDEWEB)

Pairing correlations in symmetric nuclear matter are studied within a relativistic mean-field approximation based on a field theory of nucleons coupled to neutral ({sigma} and {omega}) and to charged ({rho}) mesons. The Hartree-Fock and the pairing fields are calculated in a self-consistent way. The energy gap is the result of a strong cancellation between the scalar and vector components of the pairing field. We find that the pair amplitude vanishes beyond a certain value of momentum of the paired nucleons. This fact determines an effective cutoff in the gap equation. The value of this cutoff gives an energy gap in agreement with the estimates of nonrelativistic calculations. {copyright} {ital 1997} {ital The American Physical Society}

Matera, F.; Fabbri, G.; Dellafiore, A. [Dipartimento di Fisica, Universita degli Studi di Firenze and Istituto Nazionale di Fisica Nucleare, Sezione di Firenze, Largo Enrico Fermi 2, I-50125, Firenze (Italy)

1997-07-01

196

On the Density Dependent Nuclear Matter Compressibility  

CERN Multimedia

In the present work we apply a quantum hadrodynamic effective model in the mean-field approximation to the description of neutron stars. We consider an adjustable derivative-coupling model and study the parameter influence on the dynamics of the system by analyzing the full range of values they can take. We establish a set of parameters which define a specific model that is able to describe phenomenological properties such as the effective nucleon mass at saturation as well as global static properties of neutron stars (mass and radius). If one uses observational data to fix the maximum mass for neutron stars by a specific model, we are able to predict the compression modulus of nuclear matter K = 257,2MeV.

Dexheimer, V A; Bodmann, B E J

2007-01-01

197

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

198

Simulation study for the nuclear matter below the saturation density  

Energy Technology Data Exchange (ETDEWEB)

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)

Kido, Toshihiko; Maruyama, Toshiki; Chiba, Satoshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Niita, Koji

1999-08-01

199

Anisotropic nuclear matter with momentum-dependent interaction  

International Nuclear Information System (INIS)

A thermodynamically consistent nonthermal equation of state is presented for nuclear matter with momentum-dependent interactions in a state of anisotropic momentum distribution (expected in >2 GeV/nucleon beam energy heavy ion collisions). As an application the phase diagram for deconfinement transition of interpenetrating nuclear matter currents was constructed. (author)

1988-01-01

200

On the spin saturation and thermal properties of nuclear matter  

International Nuclear Information System (INIS)

The binding energy and the incompressibility of nuclear matter with degree of spin saturation D is calculated using the Skyrme interaction and two forms of a velocity dependent effective potential. The effect of the degree of spin saturation D on the thermal properties of nuclear matter is also discussed. It is found that generally the pressure decreases with increasing D. (author)

1983-01-01

 
 
 
 
201

Nuclear matter energy with relativistic Hamiltonian in LOCV formalism  

Energy Technology Data Exchange (ETDEWEB)

Nuclear matter energy is calculated in LOCV formalism with relativistic Hamiltonian. The equations of Euler-Lagrange are solved and two body correlation functions are calculated. We find relativistic effects on nuclear matter energy by using of these functions. The results are in agreement with other methods.

Zaryouni, S.; Moshfegh, H.R

2004-04-05

202

Nucleons, Nuclear Matter and Quark Matter: A unified NJL approach  

Energy Technology Data Exchange (ETDEWEB)

We use an effective quark model to describe both hadronic matter and deconfined quark matter. By calculating the equations of state and the corresponding neutron star properties, we show that the internal properties of the nucleon have important implications for the properties of these systems.

S. Lawley; W. Bentz; A.W. Thomas

2006-02-10

203

Dark Matter Particle Spectroscopy at the LHC: Generalizing M(T2) to Asymmetric Event Topologies  

Energy Technology Data Exchange (ETDEWEB)

We consider SUSY-like missing energy events at hadron colliders and critically examine the common assumption that the missing energy is the result of two identical missing particles. In order to experimentally test this hypothesis, we generalize the subsystem M{sub T2} variable to the case of asymmetric event topologies, where the two SUSY decay chains terminate in different 'children' particles. In this more general approach, the endpoint M{sub T2(max)} of the M{sub T2} distribution now gives the mass {tilde M}p({tilde M}{sub c}{sup (a)}, {tilde M}{sub c}{sup (b)}) of the parent particles as a function of two input children masses {tilde M}{sub c}{sup (a)} and {tilde M}{sub c}{sup (b)}. We propose two methods for an independent determination of the individual children masses M{sub c}{sup (a)} and M{sub c}{sup (b)}. First, in the presence of upstream transverse momentum PUTM the corresponding function {tilde M}p({tilde M}{sub c}{sup (a)}, {tilde M}{sub c}{sup (b)}, P{sub UTM}) is independent of P{sub UTM} at precisely the right values of the children masses. Second, the previously discussed MT2 'kink' is now generalized to a 'ridge' on the 2-dimensional surface {tilde M}p({tilde M}{sub c}{sup (a)}, {tilde M}{sub c}{sup (b)}). As we show in several examples, quite often there is a special point along that ridge which marks the true values of the children masses. Our results allow collider experiments to probe a multi-component dark matter sector directly and without any theoretical prejudice.

Konar, Partha; /Florida U.; Kong, Kyoungchul; /SLAC; Matchev, Konstantin T.; Park, Myeonghun; /Florida U.

2012-04-03

204

Nuclear stopping power in warm and hot dense matter  

Energy Technology Data Exchange (ETDEWEB)

We present a method to estimate the nuclear component of the stopping power of ions propagating in dense matter. Three kinds of effective pair potentials are proposed. Results from the warm dense matter regime and the domain of high energy density physics are presented and discussed for proton and helium. The role of ionic temperature is examined. The nuclear stopping power can play a noticeable role in hot dense matter.

Faussurier, Gerald; Blancard, Christophe [CEA, DAM, DIF, F-91 297 Arpajon (France); Gauthier, Maxence [CEA, DAM, DIF, F-91 297 Arpajon (France); LULI, Ecole Polytechnique, CNRS, CEA, UPMC, Route de Saclay, 91128 Palaiseau (France)

2013-01-15

205

Strangeness and Charm in Nuclear Matter  

CERN Document Server

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

206

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

207

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

208

Nuclear Matter and Neutron stars in a Parity Doublet Model  

CERN Multimedia

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.

Dexheimer, V; Zschiesche, D

2007-01-01

209

Reflection asymmetric nuclear shapes obtained by solving a differential equation  

International Nuclear Information System (INIS)

The equilibrium nuclear shapes in fission theory are usually obtained by minimizing the deformation energy for a given surface equation. In the following we present a method allowing to obtain a very general equilibrium (saddle-point) shape as a solution of a differential equation without an a priori introduction of a shape parametrization. In the approach based on a pure liquid drop model (LDM), saddle-point shapes are always reflection symmetric: the deformation energy increases with the mass-asymmetry parameter ? = (A1 - A2)/(A1 + A2), where ? is replaced by an almost linear dependent quantity (dL-dR)/R0. In this way the well established experimentally fission fragment mass asymmetry can not be explained. By adding the shell corrections ?E to the LDM deformation energy, Edef ELDM + ? E, we succeeded to obtain minima as shown. The nuclear surface equation of an axially symmetric body u(x) is a solution of the following differential equation: u'' = 2 + 1/u[u'2 + (x - d + Vs)(4u + u'2)3/2], where d is an input parameter which determines the deformation. In our present approach we included in the deformation energy E(R)=ELD(R) + ?E(R) - ?E0 a phenomenological shell correction ?E, and the above written differential equation is solved iteratively by using Runge-Kutta method. The procedure is repeated until the solution of the variational problem leads to the minimum of the deformation energy which is the sum of the surface and Coulomb energies plus shell corrections. At a given deformation we find the fragment volumes and the corresponding number of protons and neutrons Zi(R), Ni(R) (i=1,2).For every fragment we add contributions from protons and neutrons ?E(R) = ?i ?Ei(R) = ?i [?Epi(R) + ?Eni(R)] given by ?Epi Cs(Zi) ; ?Eni = Cs(Ni), where s(Z) = F(Z)/[(Z-2/3] - cZ1/3 and a similar equation for s(N), where F(n) = 3/5 [((Ni5/3 - Ni-15/3)/(Ni - Ni-1))(n - Ni-1) - n5/3+ Ni-15/3] in which n in (Ni-1, Ni) is the actual number of protons or neutrons Z or N, and Ni-1, Ni are the neighbouring magic numbers. The parameters c = 0.2, C = 6.2 MeV were determined by fit with experimental masses and deformations. By introducing shell corrections we obtained minima of deformation energy for parent nuclei 238 U, 232,228 Th at a finite mass asymmetry giving for the three nuclei the same mass number of the heavy fragment A1 = 125. (authors)

2001-01-01

210

Isovector nuclear matter properties and neutron skin thickness  

International Nuclear Information System (INIS)

Correlations among several nuclear matter properties are investigated in the Skyrme Hartree-Fock (SHF) and the relativistic mean field (RMF) models. The Skyrme parameters are related analytically to the isoscalar and isovector nuclear matter properties of the Hamiltonian density. Linear correlations are found among the isovector nuclear matter properties of the Hamiltonian density in both the SHF and the RMF models. We show analytically a singularity at the incompressibility Kc=306 MeV in correlations between the isovector nuclear matter properties and incompressibility with the SHF model, whereas there is no obvious singularity in those correlations with the RMF model. A linear correlation between the neutron skin thickness and the pressure of the neutron matter is given in terms of the ratio between the neutron and nuclear matter densities in the SHF model. We show that the neutron skin thickness gives crucial information about not only the neutron equation of state but also the isovector nuclear matter properties and the parametrization of the Skyrme interaction.

2006-01-01

211

Transverse charge densities in the nucleon in nuclear matter  

CERN Document Server

We investigated the transverse charge densities in the nucleon in nuclear matter within the framework of the in-medium modified Skyrme model. The medium modification of the nucleon electromagnetic form factors are first discussed. The results show that the form factors in nuclear matter fall off faster than those in free space, as the momentum transfer increases. As a result, the charge radii of the nucleon become larger, as the nuclear matter density increases. The transverse charge densities in the nucleon indicate that the size of the nucleon tends to bulge out in nuclear matter. This salient feature of the swelling is more clearly observed in the neutron case. When the proton is transversely polarized, the transverse charge densities exhibit the distortion due to the effects of the magnetization.

Yakhshiev, Ulugbek

2013-01-01

212

Transverse charge densities in the nucleon in nuclear matter  

Science.gov (United States)

We investigated the transverse charge densities in the nucleon in nuclear matter within the framework of the in-medium modified Skyrme model. The medium modification of the nucleon electromagnetic form factors are first discussed. The results show that the form factors in nuclear matter fall off faster than those in free space, as the momentum transfer increases. As a result, the charge radii of the nucleon become larger, as the nuclear matter density increases. The transverse charge densities in the nucleon indicate that the size of the nucleon tends to bulge out in nuclear matter. This salient feature of the swelling is more clearly observed in the neutron case. When the proton is transversely polarized, the transverse charge densities exhibit the distortion due to the effects of the magnetization.

Yakhshiev, Ulugbek; Kim, Hyun-Chul

2013-10-01

213

The Nucleon Mass and the EOS of Nuclear Matter  

International Nuclear Information System (INIS)

[en] 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)

2008-01-01

214

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

215

Three-dimensional numerical simulation of nuclear heating reactor under asymmetric operation condition  

Energy Technology Data Exchange (ETDEWEB)

A three-dimensional thermal-hydraulic model has been built to numerically simulate the flow and heat transfer in a 5 MW integral nuclear heating reactor (NHR-5). The simulation is performed with the general purpose commercial CFD code PHOENICS. The porous media model has been used to model the complex structure in the core and heat exchangers. The numerical model is validated by the asymmetric operation test results of the NHR-5. A comparison of the simulation results with the test results shows a good agreement. Analyses also show that shutting down half of the main heat exchangers in the NHR-5 will result in neither significant asymmetric distributions of the system parameters in the core nor a deterioration of reactor safety. [Author].

Hen Xie; Zuying Gao; Zhiwei Zhou [Tsinghua University (China). Institute of Nucelar Energy Technology

2004-07-01

216

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

217

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

218

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

219

Role of isospin in nuclear-matter liquid-gas phase transition; Role de l'isospin dans la transition de phase liquide-gaz de la matiere nucleaire  

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

220

The thermal curve of nuclear matter  

International Nuclear Information System (INIS)

[en] Earlier measurements of nuclear matter thermal curve of liquid to gas phase transition presented two limitation: only one temperature measuring method was available and the mass number of the formed nuclei decreased from 190 to 50 when the excitation energy increased. To avoid these limitations experiments with the multidetector INDRA at GANIL were carried-out. Among the quasi-projectiles issued from the 36Ar collisions at 52, 74, 95 A.MeV on the 58Ni, nuclei of close masses were selected. The excitation energy was determined by the calorimetry of the charged products emitted by quasi-projectiles while the temperature was measured by three different methods. Very different apparent temperatures were obtained for the same excitation energy/nucleon. Only one curve displays a slope variation but no indication of plateau. With the quasi-projectiles obtained from the collisions of 129Xe at 50 MeV/u on a 119Sn target behaviors similar to those of 36Ar were observed in the covered domain of excitation energy. To solve this puzzle and recover the initial temperatures of interest the only mean was to do a theoretical simulation in which one follows the de-excitation of the nuclei formed at different excitation energies and look for the thermal curve able to reproduce the observed temperatures. Two extreme possibilities were taken into account concerning the de-excitation process: either a sequential process established at E*/A? 3 MeV/u or a sudden multifragmentation in several hot fragments, most probably at E*/A? 10 MeV/u. In both cases it was possible to reproduce the whole set of experimental results concerning the 36Ar projectile. The initial temperature increases steadily as a function of excitation energy showing no plateau or singular points. The results indicate that, being a system without external pressure, in its passage from the liquid phase to the gas phase the nucleus does not display necessarily a temperature plateau. Discussions on interpretation of these results are under way

1997-01-01

 
 
 
 
221

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

222

Comparative study of three-nucleon potentials in nuclear matter  

CERN Document Server

A new generation of local three-body potentials providing an excellent description of the properties of light nuclei, as well as of the neutron-deuteron doublet scattering length, has been recently derived. We have performed a comparative analysis of the equations of state of both pure neutron matter and symmetric nuclear matter obtained using these models of three-nucleon forces. None of the considered potentials simultaneously explains the empirical equilibrium density and binding energy of symmetric nuclear matter. However, two of them provide reasonable values of the saturation density. The ambiguity concerning the treatment of the contact term of the chiral inspired potentials is discussed.

Lovato, Alessandro; Fantoni, Stefano; Schmidt, Kevin E

2011-01-01

223

National control of nuclear matters. Protection against malicious intent  

International Nuclear Information System (INIS)

This talk deals with, at first, the regulatory dispositions taken to guarantee the protection and the control of nuclear matters in installations and during transportation, and then with the general principles kept to evaluate the nuclear installations protection against malicious intent. (TEC).

1994-12-07

224

Molecular simulation of expanding matter and nuclear multifragmentation  

Energy Technology Data Exchange (ETDEWEB)

By an expanding matter model, instability of expanding nuclear matter and the dependence of fragment mass distribution on the initial temperature T{sub ini} and expanding velocity h were investigated. The expanding matter model, instability of expanding matter, fragment mass distribution were explained. Unstable nuclear matter was observed as fragments, information of nuclear matter phase transition from the experiments. Fragments are produced by expanding matter model and compared by the experimental results. When the density was fixed to {rho} = 0.05{rho}{sub 0}, the fragment mass distribution at T=8 MeV , which corresponds to the power rule distribution, was agreed with the results of calculation of Fisher model. On T=18 MeV, it showed the exponential distribution. These results showed the fragment mass distribution changed from the power rule to the exponential distribution with increasing with temperature under the condition of thermal equilibrium at the constant density. At T=5 MeV, the critical temperature or less, it showed U type distribution, which separated two parts and the small fragment became power rule type. At T{sub ini}=5, it showed power rule type. These results means the power rule deviates from the Fisher model. Accordingly, the power rule of expanding matter cannot be explained within the thermal equilibrium theory and necessary to new theory under consideration of dynamics for expanding. (S.Y.)

Chikazumi, Shinpei [Tsukuba Univ., Ibaraki (Japan). Inst. of Physics

2002-08-01

225

Molecular simulation of expanding matter and nuclear multifragmentation  

International Nuclear Information System (INIS)

[en] By an expanding matter model, instability of expanding nuclear matter and the dependence of fragment mass distribution on the initial temperature Tini and expanding velocity h were investigated. The expanding matter model, instability of expanding matter, fragment mass distribution were explained. Unstable nuclear matter was observed as fragments, information of nuclear matter phase transition from the experiments. Fragments are produced by expanding matter model and compared by the experimental results. When the density was fixed to ? = 0.05?0, the fragment mass distribution at T=8 MeV , which corresponds to the power rule distribution, was agreed with the results of calculation of Fisher model. On T=18 MeV, it showed the exponential distribution. These results showed the fragment mass distribution changed from the power rule to the exponential distribution with increasing with temperature under the condition of thermal equilibrium at the constant density. At T=5 MeV, the critical temperature or less, it showed U type distribution, which separated two parts and the small fragment became power rule type. At Tini=5, it showed power rule type. These results means the power rule deviates from the Fisher model. Accordingly, the power rule of expanding matter cannot be explained within the thermal equilibrium theory and necessary to new theory under consideration of dynamics for expanding. (S.Y.)

2002-01-01

226

Low density nuclear matter in effective ?eld theory  

Directory of Open Access Journals (Sweden)

Full Text Available The two- and three-nucleon interaction derived in chiral e?ective ?eld theory is used to obtain the binding energy of nuclear matter for small densities at next-to-leading (NLO) and next-to-next-to-leading orders (N2LO). The order N2LO is not yet su?cient to push the range of validity of the expansion beyond the empirical Fermi momentum of nuclear matter. A phenomenological extension of the interaction suggests that both e?ective three- and four-nucleon interactions are required for a description of the bulk properties of nuclear mater.

Krewald S.; Saviankou P.; Epelbaum E.; Meißner U.-G.

2010-01-01

227

QCD sum rule for nucleon in nuclear matter  

International Nuclear Information System (INIS)

We consider the two-point function of nucleon current in nuclear matter and write a QCD sum rule to analyse the residue of the nucleon pole as a function of nuclear density. The nucleon self-energy needed for the sum rule is taken as input from calculations using phenomenological N N potential. Our result shows a decrease in the residue with increasing nuclear density, as is known to be the case with similar quantities. (orig.)

2010-01-01

228

QCD sum rule for nucleon in nuclear matter  

Energy Technology Data Exchange (ETDEWEB)

We consider the two-point function of nucleon current in nuclear matter and write a QCD sum rule to analyse the residue of the nucleon pole as a function of nuclear density. The nucleon self-energy needed for the sum rule is taken as input from calculations using phenomenological N N potential. Our result shows a decrease in the residue with increasing nuclear density, as is known to be the case with similar quantities. (orig.)

Mallik, S. [Saha Institute of Nuclear Physics, Theory Division, Kolkata (India); Sarkar, Sourav [Variable Energy Cyclotron Centre, Kolkata, 700064 (India)

2010-01-15

229

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

CERN Multimedia

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

230

Femtotechnology: Nuclear Matter with Fantastic Properties  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 m...

A. A. Bolonkin

231

Pion absorption in excited nuclear matter  

Energy Technology Data Exchange (ETDEWEB)

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.).

Schmidt, H.R.; Albrecht, R.; Bock, R.; Gutbrod, H.H.; Kolb, B.W.; Lund, I. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany); Awes, T.C.; Baktash, C.; Ferguson, R.L.; Lee, I.Y.; Plasil, F.; Saini, S.; Tincknell, M.; Young, G.R. [Oak Ridge National Lab., TN (United States); Beckmann, P.; Berger, F.; Clewing, G.; Dragon, L.; Glasow, R.; Kampert, K.H.; Peitzmann, T.; Purschke, M.; Santo, R. [Muenster Univ. (Germany); Claesson, G.; Eklund, A.; Garpman, S.; Gustafsson, H.A.; Idh, J.; Oskarsson, A.; Otterlund, I.; Persson, S.; Stenlund, E. [Lund Univ. (Sweden); Franz, A. [Lawrence Berkeley Lab., CA (United States)]|[Tennessee Univ., Knoxville, TN (United States); Jacobs, P.; Poskanzer, A.M.; Ritter, H.G. [Lawrence Berkeley Lab., CA (United States); Kristiansson, P. [Lawrence Berkeley Lab., CA (United States)]|[Lund Univ. (Sweden); Loehner, H. [Muenster Univ. (Germany)]|[Groningen Univ. (Netherlands); Obenshain, F.E.; Sorensen, S.P. [Oak Ridge National Lab., TN (United States)]|[Tennessee Univ., Knoxville, TN (United States); Siemiarczuk, T. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany)]|[Inst. for Nuclear Studies, Warsaw (Poland); WA80 Collaboration

1992-02-01

232

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.).

1992-01-01

233

Pion absorption in excited nuclear matter  

Energy Technology Data Exchange (ETDEWEB)

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.).

Schmidt, H.R.; Albrecht, R.; Bock, R.; Gutbrod, H.H.; Kolb, B.W.; Lund, I. (GSI, Darmstadt (Germany)); Awes, T.C.; Baktash, C.; Ferguson, R.L.; Lee, I.Y.; Plasil, F.; Saini, S.; Tincknell, M.; Young, G.R. (Oak Ridge National Lab., TN (United States)); Beckmann, P.; Berger, F.; Clewing, G.; Dragon, L.; Glasow, R.; Kampert, K.H.; Peitzmann, T.; Purschke, M.; Santo, R. (Muenster Univ. (Germany)); Claesson, G.; Eklund, A.; Garpman, S.; Gustafsson, H.A.; Idh, J.; Oskarsson, S.; Otterlund, I.; Persson, S.; Stenlund, E. (Lund Univ. (Sweden)); Franz, A. (Lawrence Berkeley Lab., Berkeley, CA (United States) Tennessee Univ., Knoxville, TN (United States)); Jacobs, P.; Poskanzer, A.M.; Ritter, H.G. (Lawrence Berkeley Lab., Berkeley, CA (United States)); Siemiarczuk, T. (GSI, Darmstadt (Germany) Inst. for Nuclear Studies, Warsaw (Poland)); Kristiansson, P. (Lawrence Berkeley Lab., Berkeley, CA (United States) Lund Univ. (Sweden)); Loehner, H. (Muenster Univ. (Germany) Groningen Univ. (Net; WA-80 Collaboration

1992-07-20

234

Quarkyonic percolation in dense nuclear matter  

CERN Document Server

We examine the phase diagram of hadronic matter when the number of colours $N_c$, as well as temperature and density, are varied. We show that in this regime a new percolation phase transition is possible, and examine the implications of this transition for extrapolations to physical QCD of the large-N_c limit.

Lottini, Stefano

2012-01-01

235

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

236

Effect of Meson Cloud of Nucleon on Nuclear Matter Saturation  

CERN Multimedia

We investigate the effect of the meson cloud of nucleon on saturation properties of nuclear matter. Quantum correction to the scalar and vector potentials in the Walecka model is taken into account. It leads to the renormalized wave function of a nucleon in the medium, or the dressed nucleon by the meson cloud. Consequently, the NN-sigma and NN-omega coupling constants are renormalized. The renormalization constant can be related to the anomalous magnetic moment. The resultant renormalized Walecka model is able to reproduce nuclear matter saturation properties well.

Miyazaki, K

2002-01-01

237

Polarized nuclear matter using extended Seyler-Blanchard potentials  

Energy Technology Data Exchange (ETDEWEB)

In the present work the equation of state (EOS) is derived using three types of potentials for polarized nuclear matter. The potentials used are the extended Seyler-Blanchard (SB), modified Seyler-Blanchard (MSB) and the generalized Seyler-Blanchard (GSB) potentials. It is found that the equation of state derived using SB potential is a stiff EOS whereas the equations of state derived using MSB and GSB potentials are soft ones. The phase diagram for nuclear matter is also studied. The shapes are similar for the three potentials used but the critical temperatures are slightly different. {copyright} {ital 1997} {ital The American Physical Society}

Mansour, H.M.; Hammad, M.; Hassan, M.Y. [Physics Department, Faculty of Science, Cairo University, Giza (Egypt)

1997-09-01

238

On the influence of the nuclear medium on the new nuclear matter states  

International Nuclear Information System (INIS)

In many nucleus-nucleus collisions at high energies an increase of the particle production below the free nucleon-nucleon threshold has been observed. This increase can be related to the effects of the nuclear medium on the properties of the elementary particles, as well as on the new states of the nuclear matter, as resonance matter, for example. The present work takes into account the previous predictions on the rest mass particle modifications and resonance matter formation to discuss the influences of the nuclear medium on this new nuclear matter state. Experimental results on neutron-proton collisions at momenta between 1.25 GeV/c and 5.1 GeV/c, as well as on nucleus-nucleus collisions at energies between 1 A GeV and 15 A GeV are considered. Nuclear density and temperature determinations mainly at the pion emission, and the effective mass are used to establish the rest mass modification and the resonance weights in the considered collisions. A significant increase of the resonance matter formation is observed in nucleus-nucleus collisions, as compared with nucleon-nucleon collisions, at the same energy. The behaviour of the resonance matter formation in nucleus-nucleus collisions is also discussed. A like-saturation behaviour with energy increase can be considered. The major conclusion is that the nuclear medium has an important influence on the new states of nuclear matter. (authors)

2000-01-01

239

Supernovae and high density nuclear matter  

International Nuclear Information System (INIS)

The role of the nuclear equation of state (EOS) in producing prompt supernova explosions is examined. Results of calculations of Baron, Cooperstein, and Kahana incorporating general relativity and a new high density EOS are presented, and the relevance of these calculations to laboratory experiments with heavy ions considered. 31 refs., 6 figs., 2 tabs.

1986-01-01

240

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.

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

2012-01-01

 
 
 
 
241

Nuclear matter equation of state with effects of excluded volume  

International Nuclear Information System (INIS)

Phenomenological mean field models of nuclear interactions are generalized to the case where the mean fields depend not only on density but also on temperature. As an application of general formalism we extend the Walecka model to account for hard core nuclear repulsion. The effects of this modification on the phase boundary between the hadron matter and the quark-gluon plasma and on main thermodynamic functions are considered

1994-01-01

242

Nuclear power: an explosive matter; Energia nuclear: assunto explosivo  

Energy Technology Data Exchange (ETDEWEB)

This work presents a brief historic analysis of the development of nuclear power both for energy and military uses. The risk perception by the society towards this energy form is discussed. The nuclear agreements between Brazil and Germany and the USA are questioned, giving special emphasis to the social advantages and disadvantages which would raise from continuing the original plans which envisaged a total of eight nuclear power plants constructed in the country 3 figs.

Bittencourt, Silvana

1993-11-01

243

The Modification of the Scalar Field in dense Nuclear Matter  

Directory of Open Access Journals (Sweden)

Full Text Available We show the possible evolution of the nuclear deep inelastic structure function with nuclear density ?. The nucleon deep inelastic structure function represents distribution of quarks as function of Björken variable x which measures the longitudinal fraction of momentum carried by them during the Deep Inelastic Scattering (DIS) of electrons on nuclear targets. Starting with small density and negative pressure in Nuclear Matter (NM) we have relatively large inter-nucleon distances and increasing role of nuclear interaction mediated by virtual mesons.When the density approaches the saturation point, ? = ?0, we have no longer separate mesons and nucleons but eventually modified nucleon Structure Function (SF) in medium. The ratio of nuclear to nucleon SF measured at saturation point is well known as “EMC effect”. For larger density, ? > ?0, when the localization of quarks is smaller then 0.3 fm, the nucleons overlap. We argue that nucleon mass should start to decrease in order to satisfy the Momentum Sum Rule (MSR) of DIS. These modifications of the nucleon Structure Function (SF) are calculated in the frame of the nuclear Relativistic Mean Field (RMF) convolution model. The correction to the Fermi energy from term proportional to the pressure is very important and its inclusion modifies the Equation of State (EoS) for nuclear matter.

Ro?ynek J.

2011-01-01

244

Nuclear matter distribution from scattering of strongly interacting projectiles  

International Nuclear Information System (INIS)

[en] Nucleon and ?-particle scattering has been reviewed with the aspect of the information on the nuclear matter distribution, in particular at the surface, and on size and shape of nuclei. (orig.)[de] Die Streuung von Nukleonen und ?-Teilchen wird hinsichtlich ihrer Information ueber die Verteilung der nuklearen Materie an der Kernoberflaeche sowie ueber Groesse und Gestalt der Atomkerne diskutiert. (orig.)

1976-01-01

245

Comment on Baker, Brueckner, and Jastrow energies in nuclear matter  

International Nuclear Information System (INIS)

The R matrix calculation of Baker, Hind, and Kahane for the energy of nuclear matter is reanalyzed. We find that because of the Pade summation used, the R matrix theory is qualitatively similar to the usual Brueckner theory with self-energies. Both theories differ qualitatively from variational theories using Jastrow correlation functions

1977-01-01

246

Anharmonicity of the nuclear matter ground state and the RHA  

International Nuclear Information System (INIS)

The correlation between the compression modulus and the skewness coefficient of the nuclear matter ground state implied by the breathing mode data is compared with predictions of the relativistic Hartree approximation (RHA). Retaining explicit dependence on the renormalization scale ?, employed in the RHA, this correlation, together with other considerations, suggests a value for ?/M similar eq1.2. ((orig.)).

1994-01-01

247

Anharmonicity of the nuclear matter ground state and the RHA  

Energy Technology Data Exchange (ETDEWEB)

The correlation between the compression modulus and the skewness coefficient of the nuclear matter ground state implied by the breathing mode data is compared with predictions of the relativistic Hartree approximation (RHA). Retaining explicit dependence on the renormalization scale [mu], employed in the RHA, this correlation, together with other considerations, suggests a value for [mu]/M similar eq1.2. ((orig.))

Ellis, P.J. (School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States)); Heide, E.K. (School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States)); Rudaz, S. (School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States)); Prakash, M. (Physics Department, State University of New York at Stony Brook, Stony Brook, NY 11794 (United States))

1994-07-01

248

Anharmonicity of the nuclear matter ground state and the RHA  

Science.gov (United States)

The correlation between the compression modulus and the skewness coefficient of the nuclear matter ground state implied by the breathing mode data is compared with predictions of the relativistic Hartree approximation (RHA). Retaining explicit dependence on the renormalization scale ?, employed in the RHA, this correlation, together with other considerations, suggests a value for ?/M ? 1.2.

Ellis, Paul J.; Heide, Erik K.; Rudaz, Serge; Prakash, M.

1994-07-01

249

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

250

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

251

Medium modifications of baryon properties in nuclear matter and hypernuclei  

CERN Document Server

We study the medium modifications of baryon properties in nuclear many-body systems, especially in $\\Lambda$ hypernuclei. The nucleon and the $\\Lambda$ hyperon are described in the Friedberg-Lee model as nontopological solitons which interact through the self-consistent exchange of scalar and vector mesons. The quark degrees of freedom are explicitly considered in the model, so that the medium effects on baryons could be investigated. It is found that the model can provide reasonable descriptions for nuclear matter, finite nuclei, and $\\Lambda$ hypernuclei. The present model predicts a significant increase of the baryon radius in nuclear medium.

Liang, J S

2013-01-01

252

Propagation of neutrinos in nuclear matter; Effets du milieu sur la propagation des neutrinos dans la matiere nucleaire  

Energy Technology Data Exchange (ETDEWEB)

We study the elementary interactions between neutrinos and dense matter in a proto-neutron star. Equations of state obtained with different nuclear effective interactions (Skyrme, Gogny, Relativistic Lagrangians) are first discussed. Then, we characterize their stability in spin and isospin. We derive magnetic susceptibilities for all isospin asymmetry values as a function of Landau parameters G{sup {pi}}{sup {pi}}{sup '}{sub 0} (where {pi}, {pi}' = proton or neutron). From this work, we select a parametrization for each of the 3 effective forces: Sly230b,D1P,NL3. We calculate the pure neutron matter and asymmetric nuclear matter response functions with and without charge exchange, describing nuclear correlations in both approaches: non-relativistic (Hartree-Fock with Skyrme forces, then complete RPA) and relativistic (in the Hartree approximation). At the end, we calculate neutrino mean free paths neutral current and charged current reactions. Comparisons between relativistic and non-relativistic approaches allow us to identify relativistic effects in nuclear matter at densities as low as twice the saturation density. RPA correlations make the medium more transparent to neutrinos compared to free Fermi gas. The importance of the effective mass in mean free path calculations is also shown. (author)

Margueron, J

2001-07-01

253

Spinodal decomposition of expanding nuclear matter and multifragmentation  

International Nuclear Information System (INIS)

Density fluctuations of expanding nuclear matter are studied within a mean-field model in which fluctuations are generated by an external stochastic field. The time evolution of the system is studied in a kinetic-theory approach. In this model, fluctuations develop about a mean one-body phase-space density corresponding to a hydrodynamic motion that describes a slow expansion of the system. A fluctuation-dissipation relation suitable for a uniformly expanding medium is obtained and used to constrain the strength of the stochastic field. The coupling between the kinetics of fluctuations and the hydrodynamic expansion is analyzed, and the distribution of the liquid domains in the spinodal decomposition of this expanding nuclear matter is derived. It is found that the formation of the domains can be envisaged as a stationary process. Comparison of the related distribution of the fragment size with experimental data on the nuclear multifragmentation is quite satisfactory.

2003-01-01

254

Models and approximations for the momentum distribution in nuclear matter  

Energy Technology Data Exchange (ETDEWEB)

As a step toward development of a framework for phenomenological analysis of nuclear momentum distributions in terms of dynamical interparticle correlations, the momentum distribution n(k) of symmetrical nuclear matter described by a Jastrow wave function is studied within a variety of approximation schemes. In particular, two simple low-cluster-order approximations are proposed, one of which may be readily adapted to finite nuclei. For two choices of pair correlations tailored respectively to soft and moderately stiff repulsive cores, the results based on these approximations compare favorably with the standards set by Fermi-hypernetted-chain evaluation and (for the kinetic energy) by Monte Carlo integration - even at densities somewhat beyond the empirical equilibrium density of nuclear matter. The crucial role played by the Jastrow wound parameter, as a determinant of the overall behavior of n(k), emerges clearly from these calculations.

Flynn, M.F.; Clark, J.W.; Panoff, R.M. (Washington Univ., St. Louis, MO (USA). McDonnell Center for the Space Sciences; Washington Univ., St. Louis, MO (USA). Dept. of Physics); Bohigas, O. (Centre National de la Recherche Scientifique, 91 - Orsay (France). Div. de Physique Theorique); Stringari, S. (Trento Univ. (Italy). Dipartimento di Fisica)

1984-10-08

255

Variational theory of nuclear and neutron matter  

International Nuclear Information System (INIS)

In these lectures we will discuss attempts to solve the A = 3 to ? nuclear many-body problems with the variational method. We choose the form of a variational wave function ?v(1, 2 hor-ellipsis A) to describe the ground state. The ?v and the ground-state energy Ev are obtained by minimizing Ev = left-angle ?v|H|?v right-angle/left-angle ?v|?v right-angle with respect to variations in ?v. If the form of the variational wave function is chosen properly we can expect ?v ? ?0 and Ev ? E0 where ?0 and E0 are the exact ground-state wave function and energy. In general Ev ? E0 in variational calculations. 63 refs., 11 figs.

1989-06-03

256

Phase transitions in high excited nuclear matter  

International Nuclear Information System (INIS)

[en] This work is a study of the mechanism of thermal multifragmentation, which takes place in collisions of light relativistic projectiles with heavy targets. This is a new multibody decay process of very hot nuclei (target spectator) with emission of a number of intermediate mass fragments (IMF, 2 4He and 12C with Au. The main results are the following: - The mean IMF multiplicity () saturates at 2.2 ± 0.2.This fact cannot be rendered by the traditional approach with the intranuclear cascade (INC) followed by Statistical Multifragmentation Models (SMM). Considering the expansion phase between two parts of the calculations, the excitation energies and the residual masses are empirically modified to obtain agreement with the measured IMF- multiplicities. The mean excitation energy is found to be around 500 MeV for the beam energies above 5 GeV. This modified model is denoted as INC + ? + SMM where ? indicates the preequilibrium processes. - The expansion is driven by the thermal pressure. It is larger for 4He and 12C induced collisions because of higher initial temperature. The kinetic energy spectra of IMF become harder and the expansion flow is visible. The total flow energy of the system is estimated to be around 115 MeV both for the He and the carbon beams. - The analysis of the data reveals very interesting information on the fragment space distribution inside the break-up volume. Heavier IMF are formed predominately in the interior of the fragmenting nucleus possibly due to a density gradient. This conclusion is in contrast to the predictions of the Statistical Multifragmentation Model (SMM). - This study of the multifragmentation using a range of projectiles demonstrates a transition from pure '' thermal decay '' (for p + Au collisions) to disintegration '' completed by '' the onset of a collective flow for the heavier projectiles. Nevertheless, in case of reaction caused by fast protons the decay mechanism should be considered as a thermal multifragmentation. - The time scale of the thermal multifragmentation in p + Au collision at 8.1 GeV has been measured for the first time (by the analysis of IMF-IMF angular correlations). The mean decay time of the fragmenting system was found to be ? = (50 ± 18) fm/c in accordance with the scenario of a '' simultaneous '' multibody decay of a hot and expanded nuclear system. The measured time-scale is close to that for the density fluctuation in the diluted nuclear system. Hence, the thermal multifragmentation can be interpreted as the first order nuclear liquid-fog phase transition in the spinodal region. - Characteristic temperature Tf is less than Tc - critical temperature for the liquid-gas phase transition. Tc -critical temperature for the liquid-gas phase transition is found to be (17 ± 2) MeV, which is significantly larger than the temperature of fragmenting system (5 - 6 MeV). This is a very important observation in favour of the mechanism of spinodal disintegration. - It is concluded that the decay process of hot nuclei is characterized by two size parameters: transition state and freeze-out volumes. The IMF emission time is related to the mean rupture time at the multi-scission point, which corresponds to the kinetic freeze-out configuration. (author)

2006-01-01

257

Variational theory of nuclear and neutron matter  

Energy Technology Data Exchange (ETDEWEB)

In these lectures we will discuss attempts to solve the A = 3 to {infinity} nuclear many-body problems with the variational method. We choose the form of a variational wave function {Chi}{sub v}(1, 2{hor ellipsis}A) to describe the ground state. The {Chi}{sub v} and the ground-state energy E{sub v} are obtained by minimizing E{sub v} = {l angle}{Chi}{sub v}{vert bar}H{vert bar}{Chi}{sub v}{r angle}/{l angle}{Chi}{sub v}{vert bar}{Chi}{sub v}{r angle} with respect to variations in {Chi}{sub v}. If the form of the variational wave function is chosen properly we can expect {Chi}{sub v} {approx} {Chi}{sub 0} and E{sub v} {approx} E{sub 0} where {Chi}{sub 0} and E{sub 0} are the exact ground-state wave function and energy. In general E{sub v} {ge} E{sub 0} in variational calculations. 63 refs., 11 figs.

Pandharipande, V.R.; Wiringa, R.B. (Illinois Univ., Urbana, IL (USA). Dept. of Physics; Argonne National Lab., IL (USA))

1989-06-01

258

Gluon condensation and deconfinement critical density in nuclear matter  

International Nuclear Information System (INIS)

An upper limit to the critical density for the transition to the deconfined phase, at zero temperature, has been evaluated by analyzing the behavior of the gluon condensate in nuclear matter. Due to the non-linear baryon density effects, the upper limit to the critical density, ?c turns out about nine times the saturation density, ?0 for the value of the gluon condensate in vacuum =0.012 GeV4. For neutron matter ?c?8.5?0. The dependence of the critical density on the value of the gluon condensate in vacuum is studied.

2004-10-18

259

Pairing correlations in nuclear matter with realistic interactions  

Energy Technology Data Exchange (ETDEWEB)

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 [sup 3]S[sub 1]-[sup 3]D[sub 1] channel is surprisingly large, of the order of about 10 MeV. ((orig.))

Baldo, M. (Istituto Nazionale di Fisica Nucleare, Corso Italia 57, 95129 Catania (Italy) Dipartimento di Fisica dell, Universita, Corso Italia 57, 95129 Catania (Italy)); Lombardo, U. (Istituto Nazionale di Fisica Nucleare, Corso Italia 57, 95129 Catania (Italy) Dipartimento di Fisica dell, Universita, Corso Italia 57, 95129 Catania (Italy)); Bombaci, I. (Department of Physics, State University of New York at Stony Brook, Stony Brook, NY 11794 (United States) Istituto Nazionale di Fisica Nucleare, Corso Italia 57, 95129 Catania (Italy)); Schuck, P. (Institut des Sciences Nucleaires, 53 Avenue des Martyrs, F-38026 Grenoble Cedex (France))

1994-07-01

260

Resonance matter formation in relativistic nuclear collisions. Dynamical consequences  

International Nuclear Information System (INIS)

The investigation of the nuclear matter in extreme conditions is one of the most important direction in today research in the field of Relativistic Nuclear Physics. Some of the reasons are related to the possibility of investigating the state equation of the nuclear matter and the opportunity of searching phase transitions as to resonance matter or phase transition from nucleons to quarks and gluons. In this paper we review the properties of the resonant nuclear matter, the means of observing it as well as the motivations for such an enterprise. We emphasize the importance of resonance matter's formation. Resonance matter acts in two directions, namely: first, as a source for generating new particles and, second, it inhibits the transition to a total deconfined quark state, the so-called quark-gluon plasma. One way of studying resonance matter in nucleus-nucleus collision at the incident energies above 1 GeV is to look for specific nucleons resonance signals in the effective mass spectrum. For the realisation of the effective mass distributions we followed a few steps, depending on the considered experiment. For example, for SKM 200 Experiment from JINR Dubna the steps are following. First, we obtained the transverse momentum distributions for the positive particles as well as for the negative ones. Then, we approximate the transverse momentum distribution for positive particles considering its resemblance with the distribution for the negative particles. Combining the spectra for different particles we deduce the spectrum of the effective mass for the relevant decay channels. The most interesting results are included in this paper. Finally, we present the predictions of two simulations codes: UrQMD (Ultrarelativistic Quantum Molecular Dynamics) and HIJING (Heavy Ion Jet Interaction Generator) on the formation of the resonant matter in Au - Au collisions at incident energies available at RHIC (Relativistic Heavy Ion Collider) from Brookhaven National Laboratory (130 GeV/n, respectively 200 GeV/n, energies). The predictions are compared with some preliminary experimental results obtained by the BRAHMS Collaboration from RHIC-BNL. (authors)

2002-05-31

 
 
 
 
261

Pairing correlations in nuclear matter with realistic interactions  

International Nuclear Information System (INIS)

[en] 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.))

1994-01-01

262

Study of nuclear matter density distributions using hadronic probes  

International Nuclear Information System (INIS)

[en] We briefly review our formula for a proton-nucleus total reaction cross section, ?R, constructed in the black-sphere approximation of nuclei, in which a nucleus is viewed as a 'black' sphere of radius 'a'. Some years ago, using the Glauber model, one of the authors (A.K.) and his collaborators performed numerical simulations to examine the possibility to probe the nuclear matter density distributions of neutron-rich unstable nuclei from proton elastic scatterings 'model-independently'. The present study is another attempt to seek a 'model-independent' framework for systematically analyzing scattering data for studying the matter density distributions of atomic nuclei.

2011-05-06

263

Nuclear matter descriptions including quark structure of the hadrons  

International Nuclear Information System (INIS)

It is nowadays well established that nucleons are composite objects made of quarks and gluons, whose interactions are described by Quantum chromodynamics (QCD). However, because of the non-perturbative character of QCD at the energies of nuclear physics, a description of atomic nuclei starting from quarks and gluons is still not available. A possible alternative is to construct effective field theories based on hadronic degrees of freedom, in which the interaction is constrained by QCD. In this framework, we have constructed descriptions of infinite nuclear matter in relativistic mean field theories taking into account the quark structure of hadrons. In a first approach, the in medium modifications of mesons properties is dynamically obtained in a Nambu-Jona-Lasinio (NJL) quark model. This modification is taken into account in a relativistic mean field theory based on a meson exchange interaction between nucleons. The in-medium modification of mesons masses and the properties of infinite nuclear matter have been studied. In a second approach, the long and short range contributions to the in-medium modification of the nucleon are determined. The short range part is obtained in a NJL quark model of the nucleon. The long range part, related to pions exchanges between nucleons, has been determined in the framework of Chiral Perturbation theory. These modifications have been used to constrain the couplings of a point coupling relativistic mean field model. A realistic description of the saturation properties of nuclear matter is obtained. (author)

2008-01-01

264

In-medium properties of $\\Theta^{+}$ in symmetric nuclear matter  

CERN Document Server

The properties of nuclear matter is carefully analysed in relativistic mean-field formalism(RMF), it is found that the non-linear self-interaction of $\\sigma$ meson affects the properties strongly at high density and there is also strong parameter dependence in this region. We introduce a density dependent scalar coupling according to the idea of QMC model, find that its effect to properties of nuclear matter is little at low density, however, the effect at high density is obviously. The $\\Theta^{+}$ (as an structureless particle) effective masses in medium is studied, $M^*_{\\Theta^{+}}\\simeq 0.67 M_{\\Theta^{+}}$=1030 MeV at normal nuclear density. The density dependent scalar coupling obviously affects the baryon effective masses in nuclear matter, especially at high density. We review the kaon meson in medium and find the RMF model considered density dependent coupling is consistent with ChPT model in a certain extent. We develop another method to describe the $\\Theta^{+}$ in RMF, find the effective mass $M...

Zhong, X H; Zhong, Xian-Hui; Ning, Ping-Zhi

2005-01-01

265

Climate Change, Nuclear Power and Nuclear Proliferation: Magnitude Matters  

Energy Technology Data Exchange (ETDEWEB)

Integrated energy, environment and economics modeling suggests electrical energy use will increase from 2.4 TWe today to 12 TWe in 2100. It will be challenging to provide 40% of this electrical power from combustion with carbon sequestration, as it will be challenging to provide 30% from renewable energy sources. Thus nuclear power may be needed to provide ~30% by 2100. Calculations of the associated stocks and flows of uranium, plutonium and minor actinides indicate that the proliferation risks at mid-century, using current light-water reactor technology, are daunting. There are institutional arrangements that may be able to provide an acceptable level of risk mitigation, but they will be difficult to implement. If a transition is begun to fast-spectrum reactors at mid-century, without a dramatic change in the proliferation risks of such systems, at the end of the century proliferation risks are much greater, and more resistant to mitigation. The risks of nuclear power should be compared with the risks of the estimated 0.64oC long-term global surface-average temperature rise predicted if nuclear power were replaced with coal-fired power plants without carbon sequestration. Fusion energy, if developed, would provide a source of nuclear power with much lower proliferation risks than fission.

Robert J. Goldston

2010-03-03

266

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

267

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

268

Spinodal decomposition of expanding nuclear matter and multifragmentation  

CERN Multimedia

Density fluctuations of expanding nuclear matter are studied within a mean-field model in which fluctuations are generated by an external stochastic field. Fluctuations develop about a mean one-body phase-space density corresponding to a hydrodinamic motion that describes a slow expansion of the system. A fluctuation-dissipation relation suitable for a uniformly expanding medium is obtained and used to constrain the strength of the stochastic field. The distribution of the liquid domains in the spinodal decomposition is derived. Comparison of the related distribution of the fragment size with experimental data on the nuclear multifragmentation is quite satisfactory.

Matera, F; Fabbri, G

2003-01-01

269

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

270

New QCD sum rules for nucleons in nuclear matter  

International Nuclear Information System (INIS)

[en] New QCD sum rules for nucleons in nuclear matter are derived from a mixed correlation function of spin-1/2 and spin-3/2 interpolating fields. These sum rules allow a determination of the scalar self-energy of the nucleon independent of the poorly known four-quark condensates. An analysis of these new sum rules in concert with previous nucleon sum rules from spin-1/2 interpolators indicates consistency with the expectations of relativistic mean-field phenomenology. We find M* = 0.68 ± 0.08 GeV and ?v 0.31 ± 0.06 GeV at nuclear matter saturation density. (author)

1995-01-01

271

The Coester line in relativistic mean field nuclear matter  

Scientific Electronic Library Online (English)

Full Text Available 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, cla (more) imed 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

272

Mean field effects in hot compressed nuclear matter  

International Nuclear Information System (INIS)

We study effects of the mean field in hot compressed nuclear matter in the context of the Vlasov Uehling-Uhlenbeck theory. The expansion of a spherical distribution at different temperatures is studied along with collisions of Nb+Nb and Au+Au at lab energies from 50 to 1050 MeV/nucleon. In both the expansion and the actual heavy ion collision simulation, a transition behavior is seen only at the lowest temperature (T

1988-01-01

273

The properties of hot nuclear matter in LOCV formalism  

Energy Technology Data Exchange (ETDEWEB)

We calculate the equation of state of hot symmetric nuclear matter with the new charge-dependent Reid93 and AV{sub 18} potentials within the lowest order constrained variational methods (LOCV) for the wide range of densities and temperature. The liquid-gas phase transition is discussed. The flashing and critical temperature as well as the critical exponent are found for these two interactions.

Moshfegh, H.R. [Physics Department, University of Tehran, P.O. Box 14395-1547, Tehran (Iran, Islamic Republic of)]. E-mail: Moshfegh@khayam.ut.ac.ir; Modarres, M. [Physics Department, University of Tehran, P.O. Box 14395-1547, Tehran (Iran, Islamic Republic of)

2005-03-07

274

Quark mean field theory and consistency with nuclear matter  

International Nuclear Information System (INIS)

1/Nc expansion in QCD (with Nc 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, MN, m?, m? are found to scale with density. The equations are solved self consistently. (author). 29 refs, 2 tabs

1990-01-01

275

The ? potential in nuclear matter from a realistic interaction  

International Nuclear Information System (INIS)

[en] 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.))

1994-01-01

276

Quark mean field theory and consistency with nuclear matter  

International Nuclear Information System (INIS)

1/Nc expansion in QCD (with Nc 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

277

Absorption of particles in nuclear matter during tunnelling from vacuum  

International Nuclear Information System (INIS)

Due to ''soft'' hadronization of color strings heavy q anti q or N anti N pairs are created from vacuum at a relative distance > or approximately 1 Fm in their c.m.s. It is shown that during tunnelling from vacuum in the nuclear matter they are not absorbed. These two effects may explain the anomalously steep A dependence of slow anti p produced on nuclei

1984-01-01

278

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.

1999-01-01

279

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

280

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

 
 
 
 
281

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

CERN Document Server

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

282

Application of effective field theory on nuclear matter and neutron matter  

International Nuclear Information System (INIS)

In the thesis the effective field theory in NLO and NNLO order is applied. The order NLO still knows no three-particle forces. The theory yields however already in this order the saturation behaviour of nuclear matter. This is due to the fact that in the NLO order the scattering phases are qualitatively correctly reproduced, especially the scattering phases 1S0 and 3S1 are for energies above 200 MeV negative, which is in all potentials by a so called hard core represented. In the NNLO orde three-particle forces occur, which lead to a larger improvement of the saturation curve, however the saturation point lies still at too high densities. A correction of the low-energy constants by scarcely three percent of the value in the vacuum generates however a saturation curve, which reproduces the empirical binding energy per particle, the density and the compressibility of nuclear matter. About the equation of state of neutron matter is empirically few known. At small densities of neutron matter (kf-1) the NLO and NNLO orders scarcely differ, but indeed from the free Fermi gas. For applications in finite nuclei a simplified parametrization of the nucleon-nucleon interactions was developed, which reproduces both the known scattering phases with an NLO-comparable accuracy and the empirical saturation behaviour.

2009-01-01

283

Nuclear matter studies; Etude de la matiere nucleaire  

Energy Technology Data Exchange (ETDEWEB)

As the incident energy increases the time scales of the heavy ion collisions decrease. The interaction time, i.e. the time elapsing between the contact-separation moments is around 10{sup -22} and 10{sup -21} s at intermediate energies of the order of 20 {<=} E{sub bomb} {<=} 100 MeV/nucleon. At the same time, with the increasing energy the reaction mechanisms evolve and nucleon-nucleon collisions develop entailing a pre-equilibrium strong emission. Dynamical phenomena occur, as for instance, the particle and nuclear fragment emission from a nuclear matter neck linking the nuclear partners. The de-excitation of the strongly compressed and heated nuclei proceeds rapidly. Consequently, the experimental situation becomes more and more complex as the bombarding energy increases due to the superposition of the times scales of different processes. In order to achieve an as precise as possible description of the intermediate energy reaction mechanisms the events have to be detected with high efficiency (4 {pi} angular coverage and low detection thresholds). The off-equilibrium nuclear matter created in heavy ion collisions was investigated in a series of experiments based on multidetectors like NAUTILUS and INDRA. Performances concerning the angular coverage granularity and thresholds are mentioned. Also mentioned are important results obtained so far concerning the existence of a radial collective flow in the de-excitation of hot nuclei, the emission of fragments from a neck intermediate zone, as well as, the effects of proximity (space time correlations)

NONE

1998-04-01

284

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

International Nuclear Information System (INIS)

[en] 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

285

Nuclear Transparency Effect in the Strongly Interacting Matter  

CERN Multimedia

We discuss 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 K+ to pi+ -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.

Ajaz, M; Abdinov, O B; Zaman, Ali; Khan, K H; Wazir, Z; Khalilova, Sh

2012-01-01

286

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

287

Collective modes in relativistic nuclear matter: a classical approach  

International Nuclear Information System (INIS)

A classical relativistic approach based in the Vlassov equation is applied to the study of infinite nuclear matter. Hadronic matter couples to massive scalar and vector fields. The small amplitude oscillations around a stationary state are studied. Orthogonality and completeness relations and the energy weighted sum rule are obtained for the longitudinal modes. The appearance of the zero sound mode and the distribution of the strength among the different modes are discussed. It is seen that the scalar field only couples to the low energy excitations at high densities and for wave lengths not too long. The vector field couples strongly to the low energy excitations. The long wavelength limit and high density limit are studied. (author)

1990-01-01

288

Superheavy Elements at GSI - Investigating Exotic Nuclear Matter  

International Nuclear Information System (INIS)

The search for the next closed proton and neutron shells beyond 208Pb has yielded a number of exciting results in terms of the synthesis of new elements at the upper end of the charts of nuclides, in a region of exotic high-Z nuclear matter. In particular, the results obtained at the Flerov Laboratory of Nuclear Reactions (FLNR) for a rich number of decay patterns for 48Ca induced reactions on actinide targets have by now been confirmed for reactions on 238U, 244Pu and 248Cm at GSI, and on 242Pu at LBNL. These superheavy elements (SHE), however, are a nuclear structure phenomenon. They owe their existence to shell effects, an energy contribution of quantum mechanical origin to the nuclear potential, without which they would not be bound. Experimental activities in this field, apart from attempts to directly synthesize new elements, have to pursue reaction mechanism studies and, in particular, nuclear structure investigations to study the development of single particle levels towards the expected gap for the proton and neutron shell closure in the region of the spherical SHE. (author)

2010-09-05

289

Semiclassical nucleation theory for the cluster formation in nuclear matter  

International Nuclear Information System (INIS)

[en] We investigate the dynamical formation of clusters in nuclear matter. The model is based on classical nucleation theory and describes the time evolution of clusters by repeated condensation and evaporation of nucleons. We numerically calculate the growth of clusters with A?10 at temperatures of T=2 MeV and T=6 MeV and densities of ?=0.01 fm-3 and ?=0.05 fm-3. Equilibration times are rather long, 30-100 fm/c, and it is unlikely that clusters with A?10 observed in heavy-ion collisions arise from the nucleation process. (orig.)

1997-01-01

290

Hydrodynamics of nuclear matter in the chiral limit  

CERN Multimedia

Using the Poisson bracket method, we construct the hydrodynamics of nuclear matter in the chiral limit, which describes the dynamics of all low-energy degrees of freedom, including the fluid-dynamical and pionic ones. The hydrodynamic equations contain, beside five Euler equations of relativistic fluid dynamics, Nf^2-1 second order equations describing propagating pions and Nf^2-1 first order equations describing the advection of the baryonic vector isospin charges. We present hydrodynamic arguments showing that the pion velocity vanishes at the second order phase transition at Nf=2.

Son, D T

2000-01-01

291

Finite temperature RPA in symmetric nuclear matter with Skyrme interactions  

Energy Technology Data Exchange (ETDEWEB)

We investigate the RPA response for thermally excited nuclear matter interacting through Skyrme interactions. Closed analytical expressions are obtained for the dynamic susceptibility in each spin-isopspin channel. We compute the strength as a function of energy, transferred momentum and temperature, and examine the evolution of collective states, when present. The energy weighted sum rules M{sub k}, for k = -1, 1 and 3 are also shown to possess explicit expressions as functions of both momentum and temperature. It is seen that thermal effects on the susceptibility are as important as dynamical ones associated to momentum transfer, at least for temperatures as high as 20% of the Fermi energy. (orig.).

Hernandez, E.S. [Buenos Aires Univ. (Argentina). Dept. de Fisica; Navarro, J. [IFIC (Centre Mixt CSIC Universitat de Valencia), Facultat de Fisica, 46.100 Burjassot (Spain); Polls, A. [Departament d`Estructura i Constituents de la Materia, Facultat de Fisica, Universitat de Barcelona, 08028 Barcelona (Spain); Ventura, J. [Departament d`Estructura i Constituents de la Materia, Facultat de Fisica, Universitat de Barcelona, 08028 Barcelona (Spain)

1996-01-22

292

Relativistic spectral function of nucleons in hot nuclear matter  

International Nuclear Information System (INIS)

We present a simple calculation of the nucleon self-energy in nuclear matter at finite temperature in a relativistic framework, using the real-time thermal field theory. The imaginary parts of one-loop graphs are identified with discontinuities across the unitary and the Landau cuts. We find that in general both the cuts contribute significantly to the spectral function in the region of (virtual) nucleon mass usually considered, even though the unitary cut is ignored in the literature. Furthermore, our relativistic spectral function differs from the one in nonrelativistic approximation, used in some earlier calculations.

2010-01-01

293

Relativistic spectral function of nucleon in hot nuclear matter  

CERN Document Server

We present a simple calculation of the nucleon self-energy in nuclear matter at finite temperature in a relativistic framework, using the real time thermal field theory. The imaginary parts of one-loop graphs are identified with discontinuities across the unitary and the Landau cuts. We find that in general both the cuts contribute significantly to the spectral function in the region of (virtual) nucleon mass usually considered, even though the unitary cut is ignored in the literature. Also evaluation in the non-relativistic limit carried out earlier differ from the present relativistic one by as much as 25 %.

Ghosh, Sabyasachi; Sarkar, Sourav

2010-01-01

294

Pauli blocking for effective deltas in nuclear matter  

International Nuclear Information System (INIS)

The effect of Pauli blocking on the width of the ?(1232) baryon in nuclear matter is investigated. We use the mean-field approximation to quantum hadrodynamics to describe the ground state, and the ? is coupled to the density-dependent mean scalar and vector fields. The resulting width depends on the density, the momentum of the ? and on the ? coupling constants. The present work is the first step within this framework towards a self-consistent treatment of the pion and ? which would include collision spreading of the ?-width. (orig.).

1990-01-01

295

Relativistic Vlasov approach to normal modes of nuclear matter  

International Nuclear Information System (INIS)

A description of small amplitude oscillations around a stationary state in nuclear matter is formulated in the context of the relativistic Vlasov equation. We obtain a set of stationary linear modes of excitation satisfying orthogonality and completeness relations. For longitudinal modes it is explicitly shown that the system, which is made up of relativistic particles in interaction with an external scalar meson field, behaves like a system of fermions very weakly coupled to the scalar meson field, even if the coupling constant is large.

1989-01-01

296

Mass shift of sigma-Meson in Nuclear Matter  

CERN Multimedia

The propagation of sigma meson in nuclear matter is studied in the Walecka model, assuming that the sigma couples to a pair of nucleon-antinucleon states and to particle-hole states, including the in medium effect of sigma-omega mixing. We have also considered, by completeness, the coupling of sigma to two virtual pions. We have found that the sigma meson mass decreases respect to its value in vacuum and that the contribution of the sigma omega mixing effect on the mass shift is relatively small.

Morones-Ibarra, J R; Santos-Guevara, Ayax; Padilla, Felipe Robledo

2010-01-01

297

QCD sum rules for ? isobar in nuclear matter  

International Nuclear Information System (INIS)

The self-energies of ? 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 ? 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. (author). 28 refs., 1 fig.

1994-01-01

298

Nuclear matter symmetry energy from polarizabilities at low density  

International Nuclear Information System (INIS)

The nuclear matter polarizability had been proposed as a suitable framework to investigate the symmetry energy [F.L. Braghin, Nucl. Phys. A 665 (2000) 13; 696 (2001) 413; Err709 (2002) 487; F.L. Braghin, Phys. Rev. C 71 064303 (2005); Phys. Rev. C 79 069902(E) (2009); Proc. of XXX Braz. Meeting on Nucl. Phys. 2007, ed. by A. Suaide, Braz. Phys. Soc. (2008)]. It provides an original and rich conceptual framework yielding the simultaneous dependences of the symmetry energy on diverse variables. We present few different results for the symmetry energy dependence mainly on: temperature and momentum at low nuclear densities (?=0.1?0). Based on the form of the polarizability we present an argument supporting that, due to the behavior of the density fluctuations, a third order term in the n-p asymmetry can yield a more reasonable result than a linear term.

2010-03-01

299

Spin-isospin phases in nuclear matter and in nuclei  

International Nuclear Information System (INIS)

In my first lecture I talk about spin-isospin phases (SIP) in nuclear matter. I discuss in some detail the first model of nuclear binding by the OPE and I will show its connection with pion condensation. I conclude the first talk by discussing the properties of SIP and pion condensation with respect to parity and isospin. This is the subject of my second lecture. I first talk about an experiment to establish whether SIP and pion condensation are actually realized. This experiment is based on the coherent effects of a neutral weak axial current. I finally present a model of SIP in nuclei without space order and pion condensation. This kind of SIP cannot be investigated by means of the above experiment, but is characterized by enhanced M2 transition amplitudes. (orig./HSI)

1980-07-05

300

Hot nuclei and liquid - gas phase transition in nuclear matter  

International Nuclear Information System (INIS)

[en] The paper gives a popular presentation of the problem of the liquid-gas phase transition in nuclear matter. According to the models, in nucleus, as in ordinary liquid, peculiar condition can be created (high temperature and reduced density), when the system enters the region of the phase instability in respect to the liquid-gas transition (spinodal region). This state may disintegrate into ensemble of small drops (fragments), surrounded by a nuclear gas. The 'thermal' multifragmentation takes place, which is a new (multibody) decay mode of highly excited nuclei. The evidences of this scenario are considered, which have been obtained by the experiments with the FASA setup. This 4?-device is installed on the beam of relativistic light projectiles, which give the possibility to heat nucleus without the excitation of the collective degrees of freedom. (author)

1999-01-01

 
 
 
 
301

Final state interactions and hadron quenching in cold nuclear matter  

CERN Multimedia

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 a large effect on mid-rapidity hadrons at fixed target experiments. At RHIC energy, the effect is large for negative rapidity hadrons, but mild at midrapidity. This final state cold hadron quenching needs to be taken into account in jet tomographic analysis of the medium created in nucleus-nucleus collisions.

Accardi, Alberto

2007-01-01

302

Quantum teleportation of nuclear matter and its investigation  

International Nuclear Information System (INIS)

Since its discovery in 1993, quantum teleportation (QT) is a subject for intense theoretical and experimental studies. Experimental demonstration of QT has so far been limited to teleportation of light. In this paper, we propose a new experimental scheme for QT of nuclear matter. We show that the standard technique of nuclear physics experiment could be successfully applied for teleportation of spin states of atomic nuclei. We claim that there are no theoretical prohibitions upon a possibility of a complete Bell measurement, therefore, the implementation of all the four quantum communication channels is at least theoretically possible. A general expression for scattering amplitude of two 1/2-spin particles is given in the Bell operator basis, and the peculiarities of Bell states registration are briefly discussed

2003-01-01

303

Thermodynamically self-consistent class of nuclear matter EOS and compression shocks in relativistic nuclear collisions  

International Nuclear Information System (INIS)

[en] 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

304

Holographic meson mass splitting in the nuclear matter  

Science.gov (United States)

We study the holographic light meson spectra and their mass splitting in the nuclear medium. In order to describe the nuclear matter, we take into account the thermal charged AdS geometry with two flavor charges, which can be reinterpreted as the number densities of proton and neutron after some field redefinitions. We show that the meson mass splitting occurs when there exists the density difference between proton and neutron. Depending on the flavor charge, the mass of the positively (negatively) charged meson increases (decreases) as the density difference increases, whereas the neutral meson mass is independent of the density difference. In the regime of the large nucleon density with a relatively large number difference between proton and neutron, we find that negatively charged pion becomes massless in the nuclear medium, so the pion condensate can occur. We also investigate the binding energy of a heavy quarkonium in the nuclear medium, in which the binding energy of a heavy quarkonium becomes weaker as the density difference increases.

Lee, Bum-Hoon; Mamedov, Shahin; Nam, Siyoung; Park, Chanyong

2013-08-01

305

Effect of medium dependent binding energies on inferring the temperatures and freeze-out density of disassembling hot nuclear matter from cluster yields  

CERN Multimedia

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. While, 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.

Shlomo, S; Natowitz, J B; Qin, L; Hagel, K; Wada, R; Bonasera, A

2009-01-01

306

Pion condensation in a theory consistent with bulk properties of nuclear matter  

International Nuclear Information System (INIS)

A relativistic field theory of nuclear matter is solved for the self-consistent field strengths in the mean-field approximation. The theory is constrained to reproduce the bulk properties of nuclear matter. It is found that a weak pion condensate is compatible with this constraint. At least this is encouraging as concerns the possible existence of a new phase of nuclear matter. In contrast, the Lee-Wick density isomer is probably not compatible with the properties of nuclear matter. 3 figures.

1980-03-21

307

Masked mRNA is stored with aggregated nuclear speckles and its asymmetric redistribution requires a homolog of mago nashi  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Many rapidly developing systems rely on the regulated translation of stored transcripts for the formation of new proteins essential for morphogenesis. The microspores of the water fern Marsilea vestita dehydrate as they mature. During this process both mRNA and proteins required for subsequent development are stored within the microspores as they become fully desiccated and enter into senescence. At this point microspores become transcriptionally silent and remain so upon rehydration and for the remainder of spermatogenesis. Transcriptional silencing coupled with the translation of preformed RNA makes the microspore of M. vestita a useful system in which to study post-transcriptional regulation of RNA. Results We have characterized the distribution of mRNA as well as several conserved markers of subnuclear bodies within the nuclei of desiccating spores. During this period, nuclear speckles containing RNA were seen to aggregate forming a single large coalescence. We found that aggregated speckles contain several masked mRNA species known to be essential for spermatogenesis. During spermatogenesis masked mRNA and associated speckle proteins were shown to fragment and asymmetrically localize to spermatogenous but not sterile cells. This asymmetric localization was disrupted by RNAi knockdown of the Marsilea homolog of the Exon Junction Complex core component Mago nashi. Conclusions A subset of masked mRNA is stored in association with nuclear speckles during the dormant phase of microspore development in M. vestita. The asymmetric distribution of specific mRNAs to spermatogenous but not sterile cells mirrors their translational activities and appears to require the EJC or EJC components. This suggests a novel role for nuclear speckles in the post-transcriptional regulation of transcripts.

Boothby Thomas C; Wolniak Stephen M

2011-01-01

308

Masked mRNA is stored with aggregated nuclear speckles and its asymmetric redistribution requires a homolog of Mago nashi.  

UK PubMed Central (United Kingdom)

BACKGROUND: Many rapidly developing systems rely on the regulated translation of stored transcripts for the formation of new proteins essential for morphogenesis. The microspores of the water fern Marsilea vestita dehydrate as they mature. During this process both mRNA and proteins required for subsequent development are stored within the microspores as they become fully desiccated and enter into senescence. At this point microspores become transcriptionally silent and remain so upon rehydration and for the remainder of spermatogenesis. Transcriptional silencing coupled with the translation of preformed RNA makes the microspore of M. vestita a useful system in which to study post-transcriptional regulation of RNA. RESULTS: We have characterized the distribution of mRNA as well as several conserved markers of subnuclear bodies within the nuclei of desiccating spores. During this period, nuclear speckles containing RNA were seen to aggregate forming a single large coalescence. We found that aggregated speckles contain several masked mRNA species known to be essential for spermatogenesis. During spermatogenesis masked mRNA and associated speckle proteins were shown to fragment and asymmetrically localize to spermatogenous but not sterile cells. This asymmetric localization was disrupted by RNAi knockdown of the Marsilea homolog of the Exon Junction Complex core component Mago nashi. CONCLUSIONS: A subset of masked mRNA is stored in association with nuclear speckles during the dormant phase of microspore development in M. vestita. The asymmetric distribution of specific mRNAs to spermatogenous but not sterile cells mirrors their translational activities and appears to require the EJC or EJC components. This suggests a novel role for nuclear speckles in the post-transcriptional regulation of transcripts.

Boothby TC; Wolniak SM

2011-01-01

309

Calculation of the saturation properties of symmetrical nuclear matter with inclusion of & Delta -isobar  

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

2001-01-01

310

Bulk Properties of Nuclear Matter From Excitations of Nuclei  

International Nuclear Information System (INIS)

We consider the predictive power of Hartree-Fock (HF) approximation in determining properties of finite nuclei and thereby in extracting bulk properties of infinite nuclear matter (NM) by extrapolation. In particular, we review the current status of determining the value of NM incompressibility coefficient K, considering the most sensitive method of analyzing the recent accurate experimental data on excitation strengths of compression modes of nuclei within microscopic relativistic and non-relativistic theoretical models. We discuss the consequences of common violations of self-consistency in HF based random-phase-approximation calculations of strength functions and present results of highly accurate calculations of centroid energies and excitation cross sections of giant resonances. Explanations (resolutions) of long standing discrepancies in the value of K are presented

2007-10-26

311

Unstable infinite nuclear matter in stochastic mean field approach  

International Nuclear Information System (INIS)

In this article, we consider a semiclassical stochastic mean-field approach. In the case of unstable infinite nuclear matter, we calculate the characteristic time of the exponential growing of fluctuations and the diffusion coefficients associated to the unstable modes, in the framework of the Boltzmann-Langevin theory. These two quantities are essential to describe the dynamics of fluctuations and instabilities since, in the unstable regions, the evolution of the system will be dominated by the amplification of fluctuations. In order to make realistic 3D calculations feasible, we suggest to replace the complicated Boltzmann-Langevin theory by a simpler stochastic mean-field approach corresponding to a standard Boltzmann evolution, complemented by a simple noise chosen to reproduce the dynamics of the most unstable modes. Finally we explain how to approximately implement this method by simply tuning the noise associated to the use of a finite number of test particles in Boltzman-like calculations

1994-01-01

312

Quantum Vacuum in Hot Nuclear Matter A Nonperturbative Treatment  

CERN Document Server

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

313

$\\rho$ - meson spectral function in hot nuclear matter  

CERN Multimedia

We study the $\\rho$-meson spectral function in hot nuclear matter by taking into account the isospin-symmetric pion and the nucleon loops within the quantum hadrodynamics (QHD) model as well as using an effective chiral SU(3) model. The spectral function of the $\\rho$ meson is studied in the mean field approximation (MFA) as well as in the relativistic Hartree (RHA) approximation. The inclusion of the nucleon loop considerably changes the $\\rho$-meson spectral function. Due to a larger mass drop of $ \\rho $ meson in the RHA, it is seen that the spectral function shifts towards the low invariant mass region, whereas in the MFA the spectral function is seen to be slightly shifted towards the high mass region. Moreover, while the spectral function is observed to be sharper with the nucleon-antinucleon polarization in RHA, the spectral function is seen to be broader in the MFA.

Bhageerathi, P C Raje

2010-01-01

314

Tensor forces and the response functions of nuclear matter  

Energy Technology Data Exchange (ETDEWEB)

The response functions of nuclear matter in the region of small momentum transfer are evaluated within the framework of the random-phase approximation. The particle-hole interaction is assumed to be of the one-boson-exchange type and contains both central and tensor terms. Because of the tensor interaction six different channels, corresponding to different values of the total particle-hole spin and isospin, must be distinguished. A method that we have developed before for purely central forces is extended to the present case. This allows us to take properly into account the exchange diagrams, in the limit of small momentum transfer, even when the particle-hole interaction contains a tensor component.

Dellafiore, A.; Matera, F. (Dipartimento di Fisica, Universita degli Studi di Firenze, Firenze, Italy (IT) Istituto Nazionale di Fisica Nucleare, Sezione di Firenze, Firenze, Italy)

1989-08-01

315

Unstable three dimensional nuclear matter in stochastic mean field approach  

International Nuclear Information System (INIS)

A semi-classical stochastic mean-field approach is discussed. In the case of unstable infinite nuclear matter, the characteristic time of the exponential growing of fluctuations and the diffusion coefficients associated to the unstable modes are calculated in the framework of the Boltzmann-Langevin theory. In order to make realistic 3D calculations feasible, the complicated Boltzmann-Langevin theory is suggested to be replaced by a simpler stochastic meanfield approach corresponding to a standard Boltzmann evolution, complemented by a simple noise chosen to reproduce the dynamics of the most unstable modes. Finally, it is explained how to approximately implement this method by simply tuning the noise associated to the use of a finite number of test particles in Boltzmann-like calculations. (authors) 17 refs., 5 figs

1993-01-01

316

Dynamics of hot and dense nuclear and partonic matter  

International Nuclear Information System (INIS)

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.

2012-01-01

317

Dynamics of hot and dense nuclear and partonic matter  

Energy Technology Data Exchange (ETDEWEB)

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., E-mail: Elena.Bratkovskaya@th.physik.uni-frankfurt.de [Frankfurt University, Institute for Theoretical Physics (Germany); Cassing, W. [Giessen University, Institute for Theoretical Physics (Germany); Linnyk, O. [Frankfurt University, Institute for Theoretical Physics (Germany); Konchakovski, V. P. [Giessen University, Institute for Theoretical Physics (Germany); Voronyuk, V. [Frankfurt University, FIAS (Germany); Ozvenchuk, V. [Frankfurt University, Institute for Theoretical Physics (Germany)

2012-06-15

318

Liquid-gas instability and superfluidity in nuclear matter  

International Nuclear Information System (INIS)

We study effects of medium polarization on superfluidity in symmetric nuclear matter in a relativistic formalism. The effect of the liquid-gas instability is emphasized. We examine two types of decomposition of the nucleon propagator, the standard Feynman density and the particle-hole-antiparticle ones. In both cases, the medium polarization effect is determined by a characteristic cancellation among the ?, the longitudinal ?, and the ?-? mixed polarizations. The instability leads to an increase of the pairing gap. Around the saturation density, which is free from the instability, the medium polarization enhances the pairing gap in the former case and reduces it in the latter. At the lowest density, which is also free from the instability, the gap increases in both cases. (author)

2006-01-01

319

Modeling Nuclear Pasta and the Transition to Uniform Nuclear Matter with the 3D-Skyrme-Hartree-Fock Method  

CERN Multimedia

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

320

Modeling Nuclear Pasta and the Transition to Uniform Nuclear Matter with the 3D-Skyrme-Hartree-Fock Method  

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

 
 
 
 
321

Mean field effects in hot compressed nuclear matter  

Energy Technology Data Exchange (ETDEWEB)

We study effects of the mean field in hot compressed nuclear matter in the context of the Vlasov Uehling-Uhlenbeck theory. The expansion of a spherical distribution at different temperatures is studied along with collisions of Nb+Nb and Au+Au at lab energies from 50 to 1050 MeV/nucleon. In both the expansion and the actual heavy ion collision simulation, a transition behavior is seen only at the lowest temperature (T<10 MeV) or bombarding energy (E = 50 MeV/nucleon), where the attractive part of the mean field is able to bind the expanding matter. At the lowest energy one thus sees the formation of a central residue, whereas at higher bombarding energies there is complete disintegration of the centrally colliding nuclei. The spectrum of emitted nucleons is found to be much hotter than the kinetic energy spectrum of the central emitting region. The extracted temperature slope parameters are in agreement with recent data.

Molitoris, J.J.; Bonasera, A.; Winer, B.L.; Stoecker, H.

1988-03-01

322

Study of the nuclear matter flow with the multidetector INDRA  

International Nuclear Information System (INIS)

The work presented in this thesis relates to the study of the products which are not emitted by the statistical deexcitation of the projectile and target. The experiment on which this work is based on was performed at GANIL with the detector INDRA on two systems: 36 Ar + 58 Ni and 129 Xe + 119 Sn. A whole characterization (mass, composition, multiplicities and energy properties) of mid-rapidity emission has been done for the system 36 Ar + 58 Ni between 52 and 95 A.MeV. The amount of matter associated to this emission seems to be independent of the incident energy and directly linked with the centrality of the collision. The available energy per nucleon for the production of mid-rapidity products seems to be insensitive to the impact parameter. A systematic study of the nuclear matter in-plane flow has also been carried out. It has been established that the usual methods for reaction plane determination do not allow one to measure accurately the value of flow parameter at intermediate energies. Nevertheless, the inversion energy of the system 36 Ar + 58 Ni can be calculated for central collisions. This energy is independent of the nature of the products. Its value and the features of the mid-rapidity emission should allow one to extract in-medium nucleon-nucleon cross section by comparison with theoretical results. (author)

1997-01-01

323

Empirical observations on the unpredictable behavior of nuclear matter  

International Nuclear Information System (INIS)

While many aspects of matter are unpredictable from basic principles, there are some that are susceptible to empirical descriptions which can be quite accurate and beautiful. One such example from the field of ''Nuclear Matter Under Extreme Conditions'' is the distribution of the number of particles produced, or alternatively, of the energy carried by these particles, in energetic collisions of atomic nuclei. The present work consists of a series of published scientific papers on measurements of the distribution of particles produced, or the energy carried by these particles, in collisions of various nuclei, spanning more than a decade of research. Due to the unpredictability of the theory, the work includes empirical studies of the regularity of the measured distributions from which significant knowledge is gained. The aesthetics of this subject derives from the physical beauty of the measured curves, the characteristic changes of shape with different species of nuclei, and the deep understanding obtained by the use of a simple and elegant mathematical function to describe the data

1994-01-01

324

Delta and pion abundances in hot dense nuclear matter and the nuclear equation of state  

International Nuclear Information System (INIS)

Delta and pion abundances in hot dense nuclear matter are calculated self-consistently within a relativistic mean-field model for different equations of state. The density of deltas turns out to be much more sensitive to the effective masses of the baryons than to the stiffness of the equation of state. The results are compared to experimental pion yields from intermediate-energy nucleus-nucleus collisions. The influence of deviations from thermal momentum distributions for the baryons is estimated. (orig.).

1988-01-01

325

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

Science.gov (United States)

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-N limit where N 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 regime that is being recognized recently is what is called quarkyonic matter, which has both aspects of nuclear and quark matter. We closely elucidate the basic idea of quarkyonic matter in the large-N limit and its physics implications. Finally, we discuss some experimental indications for the QCD phase diagram and close the review with outlooks.

Fukushima, Kenji; Sasaki, Chihiro

2013-09-01

326

Chiral effective ?eld theory for nuclear matter including long- and short-range multi-nucleon interactions  

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.

Lacour A.; Oller J.A.; Meißner U.-G.

2010-01-01

327

Quantum Corrections on Relativistic Mean Field Theory for Nuclear Matter  

International Nuclear Information System (INIS)

We propose a quantization procedure for the nucleon-scalar meson system, in which an arbitrary mean scalar meson field ? is introduced. The equivalence of this procedure with the usual one is proven for any given value of ?. By use of this procedure, the scalar meson field in the Walecka's MFA and in Chin's RHA are quantized around the mean held. Its corrections on these theories are considered by perturbation up to the second order. The arbitrariness of ? makes us free to fix it at any stage in the calculation. When we fix it in the way of Walecka's MFA, the quantum corrections are big, and the result does not converge. When we fix it in the way of Chin's RHA, the quantum correction is negligibly small, and the convergence is excellent. It shows that RHA covers the leading part of quantum field theory for nuclear systems and is an excellent zeroth order approximation for further quantum corrections, while the Walecka's MFA does not. We suggest to fix the parameter ? at the end of the whole calculation by minimizing the total energy per-nucleon for the nuclear matter or the total energy for the finite nucleus, to make the quantized relativistic mean field theory (QRMFT) a variational method. (general)

2011-05-15

328

Stability and size of a chiral soliton immersed in nuclear matter  

Energy Technology Data Exchange (ETDEWEB)

The alteration in nucleon substructure when nucleons are placed in nuclear matter is addressed in a Wigner-Seitz approximation by treating nuclei as a collection of chiral solitons. In the limit of strong coupling between quarks and the binding chiral fields, and for low density nuclear matter, it is found the solitons decrease slightly in size. 19 refs., 3 figs.

Kahana, S.

1985-01-01

329

Nuclear matter saturation in a U(1) circle-times chiral model  

International Nuclear Information System (INIS)

The mean-field approximation in the U(1) circle-times chiral model for nuclear matter maturation is reviewed. Results show that it cannot be the correct saturation mechanism. It is argued that in this chiral model, other than the fact the ? mass can depend on the density of nuclear matter, saturation is still quite like the Walecka picture. 16 refs., 3 figs.

1989-06-17

330

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

331

Investigation methods of chemical structure based on the interaction of nuclear radiation with matter  

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

332

Variational Theory of Hot Nucleon Matter II : Spin-Isospin Correlations and Equation of State of Nuclear and Neutron Matter  

CERN Multimedia

We apply the variational theory for fermions at finite temperature and high density, developed in an earlier paper, to symmetric nuclear matter and pure neutron matter. This extension generalizes to finite temperatures, the many body technique used in the construction of the zero temperature Akmal-Pandharipande-Ravenhall equation of state. We discuss how the formalism can be used for practical calculations of hot dense matter. Neutral pion condensation along with the associated isovector spin longitudinal sum rule is analyzed. The equation of state is calculated for temperatures less than 30 MeV and densities less than three times the saturation density of nuclear matter. The behavior of the nucleon effective mass in medium is also discussed.

Mukherjee, Abhishek

2008-01-01

333

Relativistic description of BCS-BEC crossover in nuclear matter  

Energy Technology Data Exchange (ETDEWEB)

We study theoretically the di-neutron spatial correlations and the crossover from superfluidity of neutron Cooper pairs in the {sup 1}S{sub 0} pairing channel to Bose-Einstein condensation (BEC) of di-neutron pairs for both symmetric and neutron matter in the microscopic relativistic pairing theory. We take the bare nucleon-nucleon interaction Bonn-B in the particle-particle channel and the effective interaction PK1 of the relativistic mean-field approach in the particle-hole channel. It is found that the spatial structure of neutron Cooper pair wave function evolves continuously from BCS-type to BEC-type as density decreases. We see a strong concentration of the probability density revealed for the neutron pairs in the fairly small relative distance around 1.5 fm and the neutron Fermi momentum k{sub Fn} element of [0.6,1.0] fm{sup -1}. However, from the effective chemical potential and the quasiparticle excitation spectrum, there is no evidence for the appearance of a true BEC state of neutron pairs at any density. The most BEC-like state may appear at k{sub Fn}approx0.2 fm{sup -1} by examining the density correlation function. From the coherence length and the probability distribution of neutron Cooper pairs as well as the ratio between the neutron pairing gap and the kinetic energy at the Fermi surface, some features of the BCS-BEC crossover are seen in the density regions, 0.05 fm{sup -1}nuclear (pure neutron) matter.

Sun Baoyuan [School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, 100871 Beijing (China); Research Center for Nuclear Physics (RCNP), Osaka University, Ibaraki, Osaka 567-0047 (Japan); Toki, Hiroshi, E-mail: toki@rcnp.osaka-u.ac.j [Research Center for Nuclear Physics (RCNP), Osaka University, Ibaraki, Osaka 567-0047 (Japan); School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, 100871 Beijing (China); Meng Jie, E-mail: mengj@pku.edu.c [School of Physics and Nuclear Energy Engineering, Beihang University, 100191 Beijing (China); School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, 100871 Beijing (China); Department of Physics, University of Stellenbosch, Stellenbosch (South Africa); Institute of Theoretical Physics, Chinese Academy of Sciences, 100080 Beijing (China); Center of Theoretical Nuclear Physics, National Laboratory of Heavy Ion Accelerator, 730000 Lanzhou (China)

2010-01-18

334

Relativistic description of BCS-BEC crossover in nuclear matter  

International Nuclear Information System (INIS)

We study theoretically the di-neutron spatial correlations and the crossover from superfluidity of neutron Cooper pairs in the 1S0 pairing channel to Bose-Einstein condensation (BEC) of di-neutron pairs for both symmetric and neutron matter in the microscopic relativistic pairing theory. We take the bare nucleon-nucleon interaction Bonn-B in the particle-particle channel and the effective interaction PK1 of the relativistic mean-field approach in the particle-hole channel. It is found that the spatial structure of neutron Cooper pair wave function evolves continuously from BCS-type to BEC-type as density decreases. We see a strong concentration of the probability density revealed for the neutron pairs in the fairly small relative distance around 1.5 fm and the neutron Fermi momentum kFn element of [0.6,1.0] fm-1. However, from the effective chemical potential and the quasiparticle excitation spectrum, there is no evidence for the appearance of a true BEC state of neutron pairs at any density. The most BEC-like state may appear at kFn?0.2 fm-1 by examining the density correlation function. From the coherence length and the probability distribution of neutron Cooper pairs as well as the ratio between the neutron pairing gap and the kinetic energy at the Fermi surface, some features of the BCS-BEC crossover are seen in the density regions, 0.05 fm-1Fn-1, for the symmetric nuclear (pure neutron) matter.

2010-01-18

335

Dependence of relative abundances of constituents in dense stellar matter on nuclear symmetry energy  

CERN Multimedia

For a dense stellar matter, which is electrically neutral and in beta equilibrium, the electron chemical potential, mu_e, will depend nontrivially on baryonic matter density. It is generally expected that as density increases, the electron chemical potential will increase and new degrees of freedom will emerge as mu_e becomes comparable to their energy scales. Assuming the electrical neutrality and beta equilibrium for the stellar matter, we have studied how the density dependence of lepton chemical potentials varies for different models of nuclear interactions that are constrained by experiments up to nuclear matter density, n_0, but extrapolate differently(unconstrained) beyond n_0 and calculated the relative abundances of nucleons(neutron and proton) and leptons(electron and muon) and their density dependencies. We find that the density dependence of the electron chemical potential is strongly dependent on the structure of the nuclear symmetry energy relevant to softness/stfness of the nuclear matter EOS t...

Kim, Kyungmin

2009-01-01

336

Spin instabilities of infinite nuclear matter and effective tensor interactions  

CERN Document Server

We study the effects of the tensor force, present in modern effective nucleon-nucleon interactions, in the spin instability of nuclear and neutron matter. Stability conditions of the system against certain very low energy excitation modes are expressed in terms of Landau parameters. It is shown that in the spin case, the stability conditions are equivalent to the condition derived from the spin susceptibility, which is obtained as the zero-frequency and long-wavelength limit of the spin response function calculated in the Random Phase Approximation. Zero-range forces of the Skyrme type and finite-range forces of M3Y and Gogny type are analyzed. It is shown that for the Skyrme forces considered, the tensor effects are sizeable, and tend to increase the spin instability which appears at smaller densities than in the case that the tensor is not taken into account. On the contrary, the tensor contribution of finite range forces to the spin susceptibility is small or negligible for both isospin channels of symmetr...

Navarro, J

2013-01-01

337

Resilience of nuclear matter in light ion induced reactions  

International Nuclear Information System (INIS)

[en] 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

1997-01-01

338

Compression and speed of sound in nuclear matter  

International Nuclear Information System (INIS)

[en] 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

339

Multiplicity and cold-nuclear matter effects from Glauber-Gribov theory at LHC  

CERN Multimedia

We present predictions for nuclear modification factor in proton-lead collisions at LHC energy 5.5 TeV from Glauber-Gribov theory of nuclear shadowing. We have also made predictions for baseline cold-matter nuclear effects in lead-lead collisions at the same energy.

Arsene, I C; Kaidalov, A B; Tywoniuk, K; Zabrodin, E

2008-01-01

340

Parametrization of the Relativistic ($\\sigma-\\omega$) Model for Nuclear Matter  

CERN Multimedia

We calculate the equation of state of nuclear matter within the relativistic $\\so$ model. We developed a simple method to determine the strong coupling constants from the equation of state, which allow to reproduce the saturation properties of equilibrium nuclear matter. For various values of the nucleon effective mass and the compression modulus, we found that the quartic self--coupling constant $G_4$ is negative, or positive and very large. Furthermore, we showed that it is possible to reproduce all the nuclear matter properties without $G_4$, and thus we concluded that the latter is not necessary in the $\\so$ model.

Dadi, Anis ben Ali

2010-01-01

 
 
 
 
341

Asymmetric optical nuclear spin pumping in a single uncharged quantum dot  

International Nuclear Information System (INIS)

We present the observation of a unipolar optically pumped dynamic nuclear polarization (DNP) in a single self assembled InGaAs quantum dot (QD). Electrons are resonantly excited in the QD and polarize the nuclear spin system via the hyperfine contact coupling, creating an Overhauser magnetic field. Remarkably, we observe a strong asymmetry in nuclear spin pumping for excitation of the two Zeeman-split neutral exciton states. Hereby, pumping the higher energy Zeeman branch effectively polarizes the nuclear spin system, whereas the lower energy branch does not. We also find a characteristic dependence of the observed DNP on the applied magnetic field where optically induced nuclear spin pumping is most efficient for an intermediate regime of 4-6 T, with a polarization of the nuclear spin bath of 53%. A theoretical model is developed that successfully explains the empirically found features based on the exciton level structure of the system.

2011-01-01

342

Brueckner G matrix for a planar slab of nuclear matter  

International Nuclear Information System (INIS)

[en] 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

2001-01-01

343

Current status of the nuclear matter incompressibility coefficient  

International Nuclear Information System (INIS)

We review the current status of the incompressibility coefficient of symmetric nuclear matter, Knm, as deduced from experimental data on excitation cross section, ?(E), of the isoscalar giant monopole resonance (ISGMR) and the isoscalar giant dipole resonance (ISGDR), by inelastic ?-particle scattering, using the nonrelativistic and relativistic mean-field based random phase approximation (RPA). We will discuss the following problems: (1) Self-consistent (non-relativistic) Hartree-Fock (HF)-based RPA calculations and the need to carry out detailed and accurate calculations of the strength function distributions, S(E), and the transition densities, pt, of the isoscalar giant resonance within the HF-RPA theory. We will present results of our investigation concerning, (i) the consequences of violation of self-consistency in common applications of HF-based RPA on S(E) and p, of isoscalar giant resonances, and (ii) the effects of the spurious state mixing (SSM) on properties of the ISGDR. (2) The relation between the strength function S(E) and the excitation cross section a(E) of the isoscalar giant resonances (the ISGMR and the ISGDR, in particular) obtained by alpha-scattering. Here we present results of accurate microscopic calculations for S(E) and for ?(E), obtained within the folding-model distorted-wave-Born approximation with transition densities pt(r ) obtained from HF-RPA calculations. We provide an explanation for the discrepancy between theory and experiment concerning S(E) of the ISGDR. (3) The apparent discrepancy of about 20 % in the value of Knm as predicted by the relativistic and the non-relativistic models. Our investigation suggests that this discrepancy is mainly due to the different values of the symmetry energy coefficient employed in the relativistic and the non-relativistic models

2003-01-01

344

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.

2003-01-01

345

Nuclear and Condensed Matter Physics: VI Regional CRRNSM Conference. AIP Conference Proceedings, No. 513 [APCPCS  

Energy Technology Data Exchange (ETDEWEB)

This book contains 102 scientific contributions in the areas of nuclear and condensed matter physics. The conference was attended by 144 physicists, most of them belonging to the Sicilian Universities of Palermo, Catania and Messina.

Messina, A. [ed.

2000-12-31

346

Review of Mathematics, Numerical Factors, and Corrections for Dark Matter Experiments Based on Elastic Nuclear Recoil.  

Science.gov (United States)

We present a systematic derivation and discussion of the practical formulae needed to design and interpret direct searches for nuclear recoil events caused by hypothetical weakly interacting dark matter particles. Modifications to the differential energy ...

J. D. Lewin P. F. Smith

1996-01-01

347

Derivative-coupling models and the nuclear-matter equation of state  

Energy Technology Data Exchange (ETDEWEB)

The equation of state of saturated nuclear matter is derived using two different derivative-coupling Lagrangians. We show that both descriptions are equivalent and can be obtained from the {sigma}-{omega} model through an appropriate rescaling of the coupling constants. We introduce generalized forms of this rescaling to study the correlations amongst observables in infinite nuclear matter, in particular, the compressibility and the effective nucleon mass. (orig.)

Delfino, A. [Universidade Federal Fluminense Outeiro de Sao Joao Batista (Brazil). Inst. de Fisica; Chiapparini, M. [Centro Brasileiro de Pesquisas Fisicas (Brazil). Dept. de Fisica Nuclear e Altas Energias]|[Comision Nacional de Energia Atomica, TANDAR, Buenos Aires (Argentina). Dept. de Fisica; Malheiro, M. [Universidade Federal Fluminense Outeiro de Sao Joao Batista (Brazil). Inst. de Fisica; Belvedere, L.V. [Universidade Federal Fluminense Outeiro de Sao Joao Batista (Brazil). Inst. de Fisica; Gattone, A.O. [Comision Nacional de Energia Atomica, TANDAR, Buenos Aires (Argentina). Dept. de Fisica

1996-07-01

348

Derivative-coupling models and the nuclear-matter equation of state  

International Nuclear Information System (INIS)

[en] The equation of state of saturated nuclear matter is derived using two different derivative-coupling Lagrangians. We show that both descriptions are equivalent and can be obtained from the ?-? model through an appropriate rescaling of the coupling constants. We introduce generalized forms of this rescaling to study the correlations amongst observables in infinite nuclear matter, in particular, the compressibility and the effective nucleon mass. (orig.)

1996-01-01

349

Meson modes in nuclear matter with the Nambu-Jona-Lasinio model.  

Science.gov (United States)

The Nambu - Jona-Lasinio (NJL) Lagrangian, including J=0, 1 mesons is developed in order to calculate the masses and the modes of the mesons (pi), (sigma), (rho) and a(sub 1) in a dense baryonic matter. Two, different nuclear matter effects are separated:...

M. Jaminon P. Stassart R. Mendez- Galain

1992-01-01

350

Towards a unified description of asymmetric nuclear shapes in structure, fission and cluster radioactivity  

Energy Technology Data Exchange (ETDEWEB)

The description of odd intrinsic multipole moments in nuclear ground states, cluster configuration and fission by emission of heavy ions in a unified way through the introduction of a suitable collective asymmetry coordinate is proposed.

Herrmann, R.; Maruhn, J.A.; Greiner, W.

1986-12-01

351

The volume effect on nuclear fragmentation of supernova matter  

Energy Technology Data Exchange (ETDEWEB)

We proposed and have been studying a new heavy element synthesis process during supernova explosion which is proceeded by fragmentation of supernova matter through the liquid-gas phase transition. We have found that there appear the characteristic fragment distributions in the liquid-gas coexisting state during the {beta}-equilibrium of supernova matter. However, our model used for the distribution has some problems near the normal density {rho}{sub 0}. In this talk, we take into account some medium effects of supernova matter in order to improve our model. (author)

Ishizuka, C.; Ohnishi, A. [Hokkaido Univ., Sapporo (Japan). Dept. of Physics; Sumiyoshi, K. [Numazu College of Technology, Div. of Liberal Arts, Numazu, Shizuoka (Japan)

2002-09-01

352

Nuclear spirals in galaxies: gas response to asymmetric potential. II. Hydrodynamical models  

CERN Multimedia

Nuclear spirals naturally form as a gas response to non-axisymmetry in the galactic potential, even if the degree of this asymmetry is very small. Linear wave theory well describes weak nuclear spirals, but spirals induced by stronger asymmetries in the potential are clearly beyond the linear regime. Hydrodynamical models indicate spiral shocks in this latter case that, depending on how the spiral intersects the x2 orbits, either get damped, leading to the formation of the nuclear ring, or get strengthened, and propagate towards the galaxy centre. Central massive black hole of sufficient mass can allow the spiral shocks to extend all the way to its immediate vicinity, and to generate gas inflow up to 0.03 M_sun/yr, which coincides with the accretion rates needed to power luminous local Active Galactic Nuclei.

Maciejewski, Witold

2004-01-01

353

Computational methods for the nuclear and neutron-matter problems. Progress report  

International Nuclear Information System (INIS)

A new proposal for a nuclear matter/nucleus wavefunction to allow the application of Monte Carlo methods to nuclear structure problems is described. Work on calculating the binding energy of a droplet of a few 3He or 4He atoms is discussed. Also, research on choosing optimal nodal surfaces is discussed

1982-01-01

354

Ab initio calculations on nuclear matter properties including the effects of three-nucleons interaction  

CERN Multimedia

In this thesis, the ground state properties of nuclear matter, namely the energy per particle and the response to weak probes, are computed, studying the effects of three nucleon interactions. Both the variational approach, based on the formalism of correlated basis function, and the auxiliary field diffusion Monte Carlo method have been used. A scheme suitable to construct a density-dependent two-nucleon potential in correlated basis approach is discussed. The density dependent potential resulting from UIX three-nucleon force has been employed in auxiliary field diffusion Monte Carlo calculations that turned out to be in very good agreement with correlated basis variational results. Hence, the underbinding of symmetric nuclear matter has to be ascribed to deficiencies of the UXI potential. A comparative analysis of the equations of state of both pure neutron matter and symmetric nuclear matter obtained using a new generation of "chiral inspired" local three-body potentials has been performed. These potential...

Lovato, Alessandro

2012-01-01

355

Unified description of equation of state and transport properties of nuclear matter  

CERN Multimedia

Correlated basis function perturbation theory and the formalism of cluster expansions have been recently employed to obtain an effective interaction from a state-of-the-art nucleon nucleon potential model. The approach based on the effective interaction allows for a consistent description of the nuclear matter ground state and nucleon-nucleon scattering in the nuclear medium. This paper reports the the results of numerical calculations of different properties of nuclear and neutron matter, including the equation of state and the shear viscosity and thermal conductivity transport coefficients, carried out using the effective interaction.

Benhar, Omar; Fiorilla, Salvatore; Valli, Marco

2008-01-01

356

A beyond-mean-field example with zero-range effective interactions in infinite nuclear matter  

CERN Document Server

Zero-range effective interactions are commonly used in nuclear physics to describe a many-body system in the mean-field framework. If they are employed in beyond- mean-field models, an artificial ultraviolet divergence is generated by the zero-range of the interaction. We analyze this problem in symmetric nuclear matter with the t0-t3 Skyrme model. In this case, the second-order energy correction diverges linearly with the momentum cutoff. After that, we extend the work to the case of nuclear matter with the full Skyrme interaction. A strong divergence related to the velocity-dependent terms of the interaction is obtained. Moreover, a global fit can be simultaneously performed for both symmetric and nuclear matter with different neutron-to-proton ratios. These results pave the way for applications to finite nuclei in the framework of beyond mean-field theories.

Moghrabi, K; Roca-Maza, X; Coló, G; Van Giai, N; 10.1051/epjconf/20123806002

2013-01-01

357

Nuclear matter equation of state from relativistic heavy ions to supernovae  

Energy Technology Data Exchange (ETDEWEB)

In this presentation the relationship between relativistic nucleus-nucleus collisions and the nuclear equation of state is discussed. The connection between observables measured in the experiments and thermodynamic variables used to describe the system is made. Through this connection a semi-empirical nuclear equation of state is extracted from the data. The resulting equation of state is discussed in terms of nuclear matter calculations, neutron star stability and supernova collapse. 22 refs., 7 figs.

Harris, J.W.

1986-06-01

358

The determination of nuclear matter densities using strongly interacting probes  

International Nuclear Information System (INIS)

We review the many techniques which have been used to determine the ground state matter distributions of finite nuclei. Since (at present) this necessarily involves strongly interacting probes, we shall see that it is extremely difficult to obtain model independent, quantiative information. (orig.).

1980-08-30

359

Effective interaction: From nuclear reactions to neutron stars  

CERN Multimedia

An equation of state (EoS) for symmetric nuclear matter is constructed using the density dependent M3Y effective interaction and extended for isospin asymmetric nuclear matter. Theoretically obtained values of symmetric nuclear matter incompressibility, isobaric incompressibility, symmetry energy and its slope agree well with experimentally extracted values. Folded microscopic potentials using this effective interaction, whose density dependence is determined from nuclear matter calculations, provide excellent descriptions for proton, alpha and cluster radioactivities, elastic and inelastic scattering. The nuclear deformation parameters extracted from inelastic scattering of protons agree well with other available results. The high density behavior of symmetric and asymmetric nuclear matter satisfies the constraints from the observed flow data of heavy-ion collisions. The neutron star properties studied using $\\beta$-equilibrated neutron star matter obtained from this effective interaction reconcile with the ...

Basu, D N

2013-01-01

360

SACK-Expanded Hair Follicle Stem Cells Display Asymmetric Nuclear Lgr5 Expression With Non-Random Sister Chromatid Segregation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We investigated the properties of clonally-expanded mouse hair follicle stem cells (HF-SCs) in culture. The expansion method, suppression of asymmetric cell kinetics (SACK), is non-toxic and reversible, allowing evaluation of the cells' asymmetric production of differentiating progeny cells. A tight...

Huh, Yang Hoon; King, Johnathan; Cohen, Justin; Sherley, James L.

 
 
 
 
361

Matter  

CERN Document Server

The diversity of the various states of matter-solids, liquids, and gases-belies their essential similarities. All matter is composed of atoms that combine in different ways, giving us the multitude of shapes and structures we observe on a daily basis. Readers examine the different states and properties of matter, as well as the laws and forces to which matter is subject. Annotated diagrams provide visualization of complex concepts.

Publishing, Britannica Educational

2013-01-01

362

The future of the nuclear industry: a matter of communication  

International Nuclear Information System (INIS)

Since the very first successes achieved by the early scientists the infant nuclear industry was plagued by an atmosphere of uncertainty, conflict, anxiety and expectations. After the initial euphoria the Chernobyl accident shocked public opinion and perspectives changed. Nuclear energy is experience by the public in three dimensions. Firstly there are the technical realities of the reactor and its fantastically reduced source of power. Secondly, there is a psychological and political meaning, including the association of modern technology with authority, government, and control. The third dimension is the product of old myths about 'divine secrets', mad scientists dreadful pollution and cosmic apocalypse. To a large extent the nuclear industry is at fault for these emotional connotations. An early lapse in the communication process can be blamed for many of the misconceptions. The nuclear industry lost an opportunity by sticking to 'vagueness'. Recent trends show that a pattern of conditional acceptance is present in public opinion with regard to the nuclear industry. Possible solutions, including better communication, aggressive marketing, and the training of scientists to become communicators, are discussed. A study was done of community attitudes around Koeberg, and it is concluded that the public must be convinced of the fact that nuclear power is clean, safe, cheap and accepted as such by the industrially developed word. 62 refs., 13 figs.

1993-01-01

363

Near-barrier quasielastic scattering as a sensitive tool to derive nuclear matter diffuseness  

International Nuclear Information System (INIS)

Quasielastic excitation functions for the 16,18O + 60Ni systems were measured at energies near and below the Coulomb barrier, at the backward angle ?LAB = 161 deg. The corresponding quasielastic barrier distributions were derived. The data were compared with predictions from coupled channel calculations using a double-folding potential as a bare potential. For the 16O-induced scattering, good agreement was obtained for the barrier distribution by using the projectile default nuclear matter diffuseness obtained from the Sao Paulo potential systematic, that is, 0.56 fm. However, for the 18O-induced scattering, good agreement was obtained only when the projectile nuclear matter diffuseness was changed to 0.62 fm. Therefore, in this paper we show how near-barrier quasielastic scattering can be used as a sensitive tool to derive nuclear matter diffuseness.

2011-01-01

364

Search for an optimum model space for MBHF calculations of nuclear matter  

International Nuclear Information System (INIS)

The authors have performed a sequence of model-space Brueckner-Hartree-Fock nuclear matter calculations, using the Bonn A, B and C nucleon-nucleon potentials, in search of an optimum choice for the model-space boundary kM. As a function of kM and the Fermi momentum kF, the calculated nuclear matter binding energy forms a smooth concave-upward surface with a minimum in the vicinity of kM?3 fm-1. Nuclear matter saturation densities are found to vary negligibly with kM. The compression modulus may, however, be influenced by the choice of kM. 10 refs., 4 figs., 1 tab

1994-01-01

365

Sigma-omega meson coupling and properties of nuclei and nuclear matter  

Energy Technology Data Exchange (ETDEWEB)

We have constructed a Lagrangian model with a coupling of {sigma} and {omega} mesons in the relativistic mean-field theory. Properties of finite nuclei and nuclear matter are explored with the new Lagrangian model SIG-OM. The study shows that an excellent description of binding energies and charge radii of nuclei over a large range of isospin is achieved with SIG-OM. With an incompressibility of nuclear matter K=265 MeV, it is also able to describe the breathing-mode isoscalar giant monopole resonance energies appropriately. It is shown that the high-density behaviour of the equation of state of nuclear and neutron matter with the {sigma}-{omega} coupling is much softer than that of the non-linear scalar coupling model.

Haidari, Maryam M. [Physics Department, Kuwait University, Kuwait 13060 (Kuwait); Sharma, Madan M. [Physics Department, Kuwait University, Kuwait 13060 (Kuwait)], E-mail: sharma@kuc01.kuniv.edu.kw

2008-05-01

366

Sigma-omega meson coupling and properties of nuclei and nuclear matter  

CERN Document Server

We have constructed a Lagrangian model (SIG-OM) with coupling of sigma and omega mesons in the relativistic mean-field theory. Properties of finite nuclei and nuclear matter have been explored with the new Lagrangian model. The study shows that with SIG-OM an excellent description of binding energies and charge radii of nuclei over a large range of isospin is achieved. With an incompressibility of nuclear matter K=265 MeV, it is also able to describe the breathing-mode isoscalar giant mopole resonance energies successfully. It is shown that the high-density behaviour of the equation of state of nuclear and neutron matter with the sigma-omega coupling is significantly softer than the non-linear scalar coupling model.

Haidari, M M; Haidari, Maryam M.; Sharma, Madan M.

2007-01-01

367

Microscopic calculation of a pairing gap in semi-infinite nuclear matter  

International Nuclear Information System (INIS)

[en] The pairing gap in semi-infinite nuclear matter has been calculated microscopically by solving the gap equation for a nonlocal interaction with the aid of the method proposed by V.A. Khodel, A.V. Khodel, and J.W. Clark [Nucl. Phys. A 598, 390 (1996)] for the case of infinite nuclear matter. The calculation employs the effective pairing interaction obtained previously for semi-infinite geometry on the basis of the separable 3 x 3 representation of the Paris nucleon-nucleon potential. The gap found in this way changes sharply in the surface region, where it has a pronounced maximum. The dependence of the surface effect on the chemical potential of nuclear matter has been investigated

2000-01-01

368

Sigma-omega meson coupling and properties of nuclei and nuclear matter  

International Nuclear Information System (INIS)

We have constructed a Lagrangian model with a coupling of ? and ? mesons in the relativistic mean-field theory. Properties of finite nuclei and nuclear matter are explored with the new Lagrangian model SIG-OM. The study shows that an excellent description of binding energies and charge radii of nuclei over a large range of isospin is achieved with SIG-OM. With an incompressibility of nuclear matter K=265 MeV, it is also able to describe the breathing-mode isoscalar giant monopole resonance energies appropriately. It is shown that the high-density behaviour of the equation of state of nuclear and neutron matter with the ?-? coupling is much softer than that of the non-linear scalar coupling model.

2008-05-01

369

LOCV calculation of nuclear matter with phenomenological two-nucleon interaction operators  

International Nuclear Information System (INIS)

The lowest-order constrained variational (LOCV) method is developed for the wide range of phenomenological two-nucleon interaction operators such as V8, V12 and UV14 potentials. The calculation is performed for both nuclear and neutron matter with the state-dependent correlation operators. The validity of our lowest-order approximation is tested by calculating the three-body cluster energy with the state-averaged correlation functions. It is shown that while the three-body cluster energy improves the nuclear matter saturation density, the LOCV method still overbinds nuclear matter with the above potentials. Finally, we find that our LOCV results are similar to those calculations which have been performed by using more sophisticated many-body techniques. (author)

1997-01-01

370

On modification of hypothesis of partial conservation of axial-vector current in nuclear matter  

International Nuclear Information System (INIS)

Obtained are expressions generalizing voids ratios of partial concervation of axial-vector current (PCAC) for the case of infinite nuclear matter. The account of S-wave of PIN-interaction is shown to lead to the modification of PCAC in a medium. A weak axial vertex and pion-nucleon one are obtained in nuclear matter based on the theory of the finite Fermi systems. The contribution of the Fermi transitions distant from the surface is taken into account by the introduction of corresponding phenomenological constants. Obtained is the amplitude of pion decay in a medium. Its time component is determined as well. Discussed is the connection of renormalization of pion decay amplitude in a medium with the problem of PI-condensate instability of nuclear matter.

1979-01-01

371

Collective effects on transport coefficients of relativistic nuclear matter. Pt. 2  

International Nuclear Information System (INIS)

[en] The transport coefficients (thermal conductivity, shear and bulk viscosities) of symmetric nuclear matter and neutron matter are calculated in the Walecka model with a Boltzmann-Uehling-Uhlenbeck collision term by means of a Chapman-Enskog expansion in first order. The order of magnitude of the influence of collective effects induced by the presence of the mean ? and ? fields on these coefficients is evaluated. (orig.). 9 figs

1993-01-01

372

The critical temperature of nuclear matter and fragment distributions in multifragmentation of finite nuclei  

CERN Document Server

The fragment production in multifragmentation of finite nuclei is affected by the critical temperature of nuclear matter. We show that this temperature can be determined on the basis of the statistical multifragmentation model (SMM) by analyzing the evolution of fragment distributions with the excitation energy. This method can reveal a decrease of the critical temperature that, e.g., is expected for neutron-rich matter. The influence of isospin on fragment distributions is also discussed.

Ogul, R

2002-01-01

373

Hyper matter-properties and formation in relativistic nuclear collisions  

International Nuclear Information System (INIS)

The extension of the Periodic System into hitherto unexplored domains - antimatter and hyper matter - is discussed. Starting from an analysis of hyperon and single hypernuclear properties we investigate the structure of multi-hyperon objects (MEMOs) using and extended relativistic meson field theory. Those are contrasted with multi-strange quark states (strange lets). Their production mechanism is studied for relativistic collisions of heavy ions from present day experiments at Ags and Sps to future opportunities at RHIC and LH C. It is pointed out that absolutely stable hyper matter is unlikely to be produced in heavy ion collisions. New attention should be focused on short lived metastable hyper clusters (? ? 10 -1- s) and on intensity interferometry of multi-strange-baryon correlations. (author)

1996-01-01

374

Nuclear matter at high temperature and low net baryonic density  

International Nuclear Information System (INIS)

[en] We study the effect of the ?-? mesons interaction on nucleon-antinucleon matter properties. This interaction is employed in the context of the linear Walecka model to discuss the behavior of this system at high temperature and low net baryonic density regime. The field equations are solved in the relativistic mean-field approximation and our results show that the phase transition pointed out in the literature for this regime is eliminated when the meson interaction are considered.

2010-11-12

375

Asymmetric radiation of seismic waves from an atoll: nuclear tests in French Polynesia  

Science.gov (United States)

Seismic records of nuclear tests detonated in the Mururoa Atoll in French Polynesia show large unpredicted arrivals 2.2 and 4.5 seconds (X1 and X2) after the P-wave at the Australian Warramunga Array. These arrivals are not observed at the Canadian Yellowknife Array. X1 and X2 are also absent on Warramunga Array recordings of tests carried out at the Fangataufa Atoll situated 40 km SSE of Mururoa. Array analysis shows that X1 and X2 are produced within the source area. The layered crustal structure of the atoll, significant local inhomogeneities, and focusing effects due to the elongated shape and the steep flanks of the Mururoa Atoll are most likely responsible for X1 and X2. The form of Mururoa (28 × 10 km) and its East-West orientation is due to its location on the Austral Fracture Zone (AFZ). The Fangataufa Atoll on the other hand is almost circular (10 km diameter) and is unaffected by the dynamics along the AFZ. Our observations demonstrate that complicated structures in the source area can significantly alter the wave field at teleseismic distances and produce a large magnitude (mb) bias. A better understanding of the exact cause of these unusual seismic observations will only become possible, if the coordinates of the tests and information on the detailed 3-D structure of the atolls are released.

Weber, Michael; Wicks, Charles W., Jr.; Krüger, Frank; Jahnke, Gunnar; Schlittenhardt, Jörg

1998-01-01

376

Describing hot and dense nuclear matter with gauged linear {sigma}-model  

Energy Technology Data Exchange (ETDEWEB)

To describe nuclear matter at high temperature and high baryon density appropriate for RHIC and LHC, an effective theory is proposed. Three developments underlie the effective theory: (1) relativistic mean field theory description of nuclear matter with mesons mediating interactions; (2) topological soliton description of the nucleon with hidden local symmetry; (3) phenomenological knowledge of nucleon-nucleon interaction and nucleon structure obtained from elastic NN scattering at c.m.energies of hundreds of GeV. When these developments are combined together, a gauged linear a-model with anomalous action and condensed quark-antiquark ground state emerges as the effective theory. (author)

Islam, M.M. [Connecticut Univ., Storrs, CT (United States). Dept. of Physics

1999-07-01

377

Many-body correlations in Semiclassical Molecular Dynamics and Skyrme forces for symmetric Nuclear Matter  

CERN Multimedia

Constraint Molecular dynamics CoMD calculations have been performed for symmetric nuclear matter (NM) by using a simple effective interactions of the Skyrme type. The set of parameter values reproducing common accepted saturation properties of nuclear matter have been obtained for different degree of stiffness characterizing the iso-vectorial potential density dependence. A comparison with results obtained in the limit of the Semi-Classical Mean Field approximation performed using the same kind of interaction put in evidence the role played by the many-body correlations present in the model explaining also the noticeable differences obtained in the parameter values in the two cases

Papa, Massimo

2012-01-01

378

Experimental Determination of In-Medium Cluster Binding Energies and Mott Points in Nuclear Matter  

CERN Document Server

In medium binding energies and Mott points for $d$, $t$, $^3$He and $\\alpha$ clusters in low density nuclear matter have been determined at specific combinations of temperature and density in low density nuclear matter produced in collisions of 47$A$ MeV $^{40}$Ar and $^{64}$Zn projectiles with $^{112}$Sn and $^{124}$Sn target nuclei. The experimentally derived values of the in medium modified binding energies are in good agreement with recent theoretical predictions based upon the implementation of Pauli blocking effects in a quantum statistical approach.

Hagel, K; Qin, L; Natowitz, J B; Shlomo, S; Bonasera, A; Röpke, G; Typel, S; Chen, Z; Huang, M; Wang, J; Zheng, H; Kowalski, S; Bottosso, C; Barbui, M; Rodrigues, M R D; Schmidt, K; Fabris, D; Lunardon, M; Moretto, S; Nebbia, G; Pesente, S; Rizzi, V; Viesti, G; Cinausero, M; Prete, G; Keutgen, T; Masri, Y El; Majka, Z

2012-01-01

379

BCS-BEC crossover and liquid-gas phase transition in nuclear matter  

Energy Technology Data Exchange (ETDEWEB)

The effect of nucleon-nucleon correlations in symmetric nuclear matter at finite temperature is studied beyond BCS theory. We calculate the critical temperature for a BEC superfluid of deuterons, of a BCS superfluid of nucleons, and in the crossover between these limits. The effect of the correlations on the liquid-gas phase transition is discussed. Our results show that nucleon-nucleon correlations beyond BCS play an important role for the properties of nuclear matter, especially in the low-density region.

Jin Meng [Institute of Particle Physics and Physical Department, Central China Normal University, Wuhan 4300079 (China); Urban, Michael [Groupe de Physique Theorique, Institut de Physique Nucleaire -Centre Scientifique d' Orsay, F-91406 Orsay (France); Schuck, Peter, E-mail: jinm@iopp.ccnu.edu.cn [Laboratoire de Physique et Modelisation des Milieux Condenses,CNRS and Universite Joseph Fourier, BP 166, 38042 Grenoble Cedex (France)

2011-09-16

380

75 FR 35846 - In the Matter of Babcock & Wilcox Nuclear Operations Group, Inc., Lynchburg, VA; Order Imposing...  

Science.gov (United States)

...70-27; License No. SNM-42; EA-08-204] In the Matter of Babcock & Wilcox Nuclear Operations Group, Inc., Lynchburg, VA; Order Imposing Civil Monetary Penalty I Babcock & Wilcox Nuclear Operations Group, Inc., (Licensee) is...

2010-06-23

 
 
 
 
381

Rescattering and energy loss of fast partons in nuclear matter  

International Nuclear Information System (INIS)

We compare nuclear rescattering and energy loss effects as seen in dijet production in Fermilab fixed target experiment E609 with theoretical estimates and with data from Drell-Yan dilepton production. Possible explanations for these effects being unusually large in dijet production are briefly discussed

1993-01-01

382

Instabilities in nuclear and neutron matter at subnuclear densities  

International Nuclear Information System (INIS)

[en] The development of the density and temperature inhomogeneities arising in collision of heavy ions is investigated on the basis of Landau Fermi liquid theory. With discussed the mechanism of nuclear fragmentation as a result of these inhomogeneities. Comparison is made with the earlier works carried out by using various types of interaction functions. (authors)

2001-01-01

383

The Asymmetric Binding of PGC-1? to the ERR? and ERR? Nuclear Receptor Homodimers Involves a Similar Recognition Mechanism  

Science.gov (United States)

Background PGC-1? is a crucial regulator of cellular metabolism and energy homeostasis that functionally acts together with the estrogen-related receptors (ERR? and ERR?) in the regulation of mitochondrial and metabolic gene networks. Dimerization of the ERRs is a pre-requisite for interactions with PGC-1? and other coactivators, eventually leading to transactivation. It was suggested recently (Devarakonda et al) that PGC-1? binds in a strikingly different manner to ERR? ligand-binding domains (LBDs) compared to its mode of binding to ERR? and other nuclear receptors (NRs), where it interacts directly with the two ERR? homodimer subunits. Methods/Principal Findings Here, we show that PGC-1? receptor interacting domain (RID) binds in an almost identical manner to ERR? and ERR? homodimers. Microscale thermophoresis demonstrated that the interactions between PGC-1? RID and ERR LBDs involve a single receptor subunit through high-affinity, ERR-specific L3 and low-affinity L2 interactions. NMR studies further defined the limits of PGC-1? RID that interacts with ERRs. Consistent with these findings, the solution structures of PGC-1?/ERR? LBDs and PGC-1?/ERR? LBDs complexes share an identical architecture with an asymmetric binding of PGC-1? to homodimeric ERR. Conclusions/Significance These studies provide the molecular determinants for the specificity of interactions between PGC-1? and the ERRs, whereby negative cooperativity prevails in the binding of the coactivators to these receptors. Our work indicates that allosteric regulation may be a general mechanism controlling the binding of the coactivators to homodimers.

Takacs, Maria; Petoukhov, Maxim V.; Atkinson, R. Andrew; Roblin, Pierre; Ogi, Francois-Xavier; Demeler, Borries; Potier, Noelle; Chebaro, Yassmine; Dejaegere, Annick; Svergun, Dmitri I.; Moras, Dino; Billas, Isabelle M. L.

2013-01-01

384

Properties of charmed and bottom hadrons in nuclear matter A plausible study  

CERN Multimedia

Changes in properties of heavy hadrons with a charm or a bottom quark are studied in nuclear matter. Effective masses (scalar potentials) for the hadrons are calculated using quark-meson coupling model. Our results also suggest that the heavy baryons containing a charm or a bottom quark will form charmed or bottom hypernuclei, which was first predicted in mid 70's. In addition a possibility of $B^-$-nuclear bound (atomic) states is briefly discussed.

Tsushima, K

2003-01-01

385

Nuclear Matter for compact stars and its properties  

CERN Document Server

A pure nucleonic equation of state (EoS) for beta equilibrated charge neutral neutron star (NS) matter is determined using density dependent effective NN interaction. This EoS is found to satisfy both the constraints from the observed mass-radius of neutron stars and flow data from heavy-ion collisions. Recent observations of the binary millisecond pulsar J1614-2230 by P. B. Demorest et al. [1] suggest that the masses lie within (1.97\\pm 0.04) M_\\odot (M_\\odot, solar mass). Most EoS involving exotic matter, such as kaon condensates or hyperons, tend to predict maximum masses well below 2.0M_\\odot and are therefore ruled out. We are able to reproduce the measured mass-radius relationship for rotating and static NS. We ensure that the star rotating not faster than the frequency limited by r-mode instability gives the maximum mass about 1.95M_\\odot with radius about 10 kilometer.

Chowdhury, Partha Roy

2011-01-01

386

Fermionic condensation in ultracold atoms, nuclear matter and neutron stars  

CERN Multimedia

We investigate the Bose-Einstein condensation of fermionic pairs in three different superfluid systems: ultracold and dilute atomic gases, bulk neutron matter, and neutron stars. In the case of dilute gases made of fermionic atoms the average distance between atoms is much larger than the effective radius of the inter-atomic potential. Here the condensation of fermionic pairs is analyzed as a function of the s-wave scattering length, which can be tuned in experiments by using the technique of Feshbach resonances from a small and negative value (corresponding to the Bardeen-Cooper-Schrieffer (BCS) regime of Cooper Fermi pairs) to a small and positive value (corresponding to the regime of the Bose-Einstein condensate (BEC) of molecular dimers), crossing the unitarity regime where the scattering length diverges. In the case of bulk neutron matter the s-wave scattering length of neutron-neutron potential is negative but fixed, and the condensate fraction of neutron-neutron pairs is studied as a function of the to...

Salasnich, Luca

2013-01-01

387

Investigation of compressed and highly excited nuclear matter in relativistic heavy ion collisions  

International Nuclear Information System (INIS)

[en] The gross properties of nuclear matter at high densities and temperatures and the significance of the nuclear equation of state for high energy nuclear collisions are investigated within the nuclear fluid dynamical model. The hydrdynamical description and the properties of the nuclear fluid are extensively discussed. It is shown that at bombarding energies of 1-4 GeV/n compressions of 3-6 psub(o) and temperatures T approx. 100 MeV can be reached. At medium energies we compare the nuclear fluid dynamical model and the time-dependent Hartree-Fock model. The importance of isobaric resonance - and pion production at higher energies is discussed, which for an exponentially increasing hadronic mass spectrum leads to a limiting temperature Tsup(Max). (orig.)

1979-01-01

388

Ionization Yield from Nuclear Recoils in Liquid-Xenon Dark Matter Detection  

CERN Document Server

The ionization yield in the two-phase liquid xenon dark-matter detector has been studied in keV nuclear-recoil energy region. The newly-obtained nuclear quenching as well as the recently-measured average energy required to produce an electron-ion pair are used to calculate the total electric charges produced. To estimate the fraction of the electron charges collected, the Thomas-Imel model is generalized to describing the field dependence for nuclear recoils in liquid xenon. With free parameters fitted to experiment measured 56.5 keV nuclear recoils, the energy dependence of ionization yield for nuclear recoils is predicted, which increases with the decreasing of the recoiling energy and reaches the maximum value at 2~3 keV. This prediction agrees well with existing data and may help to lower the energy detection threshold for nuclear recoils to ~1 keV.

Mu, Wei

2013-01-01

389

Soliton scattering in nuclear matter in one dimension  

International Nuclear Information System (INIS)

[en] We have considered a model Hamiltonian system in one dimension with higher order nonlinearity to simulate the excitations of nuclear ''drops'' or ''solitons'' in the background of the usual vacuum. The theory is usually referred to as ?4-?6 theory and has been already used in many different physical contexts. Essentially we have considered the interaction of two such solitary excitations and their subsequent evolution regarding amplitude and phase. 6 refs. (author)

1986-01-01

390

Historical trend of nuclear matter calculation and its recent developments  

International Nuclear Information System (INIS)

He guide line to understand nuclear properties on the basis of nuclear force was started in the 1950's by the Brueckner theory. The theory established the fundamental framework to formulate the picture to consider both the two nucleon and tensor correlations as well as Pauli effect inside the nuclei. In the 1960's the theory was developed to obtain ground state energy on the perturbation many-body theory. The growth and refinement of the Brueckner theory in the 1970's and after are overviewed and the computer code developments in the 1980's are mentioned. Concerning the many-body correlation problem Italian group has calculated up to three-body correlations in the Brueckner theory. At present, effective interaction nuclear theory is coming into a new level and actively studied by the introduction of low momentum interaction based on the renormalization group theory, by full application of the coupled cluster method, by the application of Skyrme Hartree-Fock method in wide range and by the reconsideration of the energy density functional method in relation to the relativistic mean field method. Owing to the recent remarkable progress of computers, calculations which were impossible to be executed in old days are now done rather easily. (S. Funahashi)

2006-01-01

391

Nuclear Magnetic Biosignatures in the Carbonaceous Matter of Ancient Cherts: Comparison with Carbonaceous Meteorites.  

UK PubMed Central (United Kingdom)

Abstract The search for organic biosignatures is motivated by the hope of understanding the conditions of emergence of life on Earth and the perspective of finding traces of extinct life in martian sediments. Paramagnetic radicals, which exist naturally in amorphous carbonaceous matter fossilized in Precambrian cherts, were used as local structural probes and studied by electron paramagnetic resonance (EPR) spectroscopy. The nuclear magnetic resonance transitions of elements inside and around these radicals were detected by monitoring the nuclear modulations of electron spin echo in pulsed EPR. We found that the carbonaceous matter of fossilized microorganisms with age up to 3.5 billion years gives specific nuclear magnetic signatures of hydrogen ((1)H), carbon ((13)C), and phosphorus ((31)P) nuclei. We observed that these potential biosignatures of extinct life are found neither in the carbonaceous matter of carbonaceous meteorites (4.56 billion years), the most ancient objects of the Solar System, nor in any carbonaceous matter resulting from carbonization of organic and bioorganic precursors. These results indicate that these nuclear signatures are sensitive to thermal episodes and can be used for Archean cherts with metamorphism not higher than the greenschist facies. Key Words: Kerogen-Biosignatures-Origin of life-Archean-EPR spectroscopy. Astrobiology 13, xxx-xxx.

Gourier D; Delpoux O; Binet L; Vezin H

2013-10-01

392

Effect of sound branch of pion on non-mesonic {Lambda} decay in nuclear matter  

Energy Technology Data Exchange (ETDEWEB)

It is studied the effect of the sound branch of pion on the non-mesonic decay width of the {Lambda} in nuclear matter. It is funded that its effect is sensitive to the energy release and the correlation parameter g`.

Nagano, K.; Akiyama, S.; Futami, Y. [Tokio Science Univ., Chiba (Japan). Dept of Phisics

1996-10-01

393

NUCLEAR ANALYTICAL TECHNIQUES INAA AND PIXE APPLICATION FOR CHARACTERIZATION OF AIRBORNE PARTICULATE MATTER IN INDONESIA  

Directory of Open Access Journals (Sweden)

Full Text Available Nuclear analytical techniques such as Instrumental neutron activation analysis (INAA) and Particle Induced X-ray Emission (PIXE) have been used in quantification of environmental pollutant. INAA and PIXE have been turned out to be particularly useful in the analysis of airborne particulate matter. Nuclear Energy Agency of Indonesia has carried out the monitoring air quality especially for airborne particulate matter using nuclear analytical techniques. Sampling of airborne particulate matter was carried out twice a week for 24 hours in an urban area Bandung and in a suburban area Lembang, Indonesia. The samples were collected using a Gent stacked filter unit sampler in two size fractions of < 2.5 µm (fine) and 2.5 to 10 µm (coarse). The samples were analyzed for elemental concentrations by INAA at TRIGA 2000 Bandung reactor and PIXE at Institute of Geological and Nuclear Sciences, New Zealand. The validation of INAA method was done using NIST SRM 1648 airborne particulate matter. Both techniques provide more than 30 significant elements for identification the possible sources of atmospheric aerosol. The results demonstrated that INAA and PIXE are suitable for characterization of trace elements in APM samples.

MUHAYATUN SANTOSO; DIAH DWIANA LESTIANI; PHILIP K HOPKE; ANDREAS MARKWITZ

2010-01-01

394

The Hugenholtz-Van Hove theorem in nuclear matter calculations with density-dependent effective interactions  

International Nuclear Information System (INIS)

[en] It is pointed out that first-order nuclear matter calculations with effective interactions must satisfy the Hugenholtz-Van Hove theorem and that this tells one nothing about the validity of the interaction itself. Unawareness of this fact has given rise to incorrect statements and misleading conclusions in the literature which this paper points out and rectifies. (author)

1980-01-01

395

Time scales for spinodal decomposition in nuclear matter with pseudo-particle model  

International Nuclear Information System (INIS)

Dynamical instabilities arising from fluctuations in the spinodal zone for nuclear matter are studied using a large variety of zero range interactions in the frame of a pseudo-particle model. Scale times for spinodal decomposition are extracted and a possible link with decomposition in real heavy-ion collisions is discussed. (author) 12 refs.; 6 figs.; 1 tab

1993-01-01

396

Hypernetted-chain integral equations for inhomogeneous spin-isospin-ordered nuclear matter  

Energy Technology Data Exchange (ETDEWEB)

A laminated configuration of nuclear matter, characterized by one-dimensional density fluctuations and spin-isospin order has been considered. A set of HNC integral equations for the one-body and the two-body distribution functions and the one-body density matrix has been obtained.

Benhar, O. (Istituto Superiore di Sanita, Rome (Italy); Radiation Lab. Rome (Italy))

1981-04-25

397

Investigation of excited nuclear matter in relativistic nucleus-nucleus collisions  

International Nuclear Information System (INIS)

[en] Baryon cluster production in p, d, He and C collisions with carbon nuclei at P=4x2xA GeV/c and hadron jet production in ?-C interactions at P=40 GeV/c are studied interms of relativistic-invariant approach. The evaluations of temperature and density values of nuclear matter in this process are given

1990-01-01

398

Nuclear matter and chiral phase transition at large-$N_{c}$  

CERN Document Server

Two aspects of the QCD phase diagrams are studied in the limit of a large number of colors: at zero temperature and nonzero density the (non)existence of nuclear matter, and at zero density and nonzero temperature the chiral phase transition.

Giacosa, Francesco

2011-01-01

399

Computational methods for the nuclear and neutron matter problems. Progress report  

International Nuclear Information System (INIS)

A brief report is given of progress on the development of Monte Carlo methods for the treatment of both simplified and realistic models of extensive neutron and nuclear matter and, eventually, of finite nuclei. A wide class of algorithms that may allow the efficient sampling of the integrands required in calculating the energy expectations with useful trial wave functions was devised.

1979-01-01

400

Clusters and Fragments Formed in Expanding Nuclear Matter in Heavy-Ion Collisions  

International Nuclear Information System (INIS)

Formation of clusters and fragments is discussed as an important aspect of properties of bulk nuclear matter produced in heavy ion collisions. Development of antisymmetrized molecular dynamics is reviewed with an emphasis on an extension to take account of many-body correlations.

2009-05-07

 
 
 
 
401

Thermodynamical Properties of Nuclear Matter from a newline Self-Consistent Green's Function Approach  

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 t...

Rios Huguet, Arnau

402

Simple explanation of anomalous absorption of 3? in the 0-S state in nuclear matter  

International Nuclear Information System (INIS)

Interactions between components of the three-pion system propagating through nuclear matter are taken into account. An excellent description of sigmasub(3?N) for various spin states of this system are obtained. Some predictions for other reactions are given. (Auth.)

1978-04-17

403

Relativistic Study of Medium Polarization Effects on Superfluidity in Nuclear Matter  

CERN Multimedia

Effects of the Fermi-sea polarization on the superfluidity in nuclear matter are studied in a framework of quantum hadrodynamics. The particle-hole polarization due to $\\sigma$ and $\\omega$ mesons enhances the peak value of the pairing gap contrary to the previous non-relativistic studies.

Matsuzaki, M; Matsuzaki, Masayuki; Ring, Peter

1997-01-01

404

Nuclear magnetic biosignatures in the carbonaceous matter of ancient cherts: comparison with carbonaceous meteorites.  

UK PubMed Central (United Kingdom)

Abstract The search for organic biosignatures is motivated by the hope of understanding the conditions of emergence of life on Earth and the perspective of finding traces of extinct life in martian sediments. Paramagnetic radicals, which exist naturally in amorphous carbonaceous matter fossilized in Precambrian cherts, were used as local structural probes and studied by electron paramagnetic resonance (EPR) spectroscopy. The nuclear magnetic resonance transitions of elements inside and around these radicals were detected by monitoring the nuclear modulations of electron spin echo in pulsed EPR. We found that the carbonaceous matter of fossilized microorganisms with age up to 3.5 billion years gives specific nuclear magnetic signatures of hydrogen ((1)H), carbon ((13)C), and phosphorus ((31)P) nuclei. We observed that these potential biosignatures of extinct life are found neither in the carbonaceous matter of carbonaceous meteorites (4.56 billion years), the most ancient objects of the Solar System, nor in any carbonaceous matter resulting from carbonization of organic and bioorganic precursors. These results indicate that these nuclear signatures are sensitive to thermal episodes and can be used for Archean cherts with metamorphism not higher than the greenschist facies. Key Words: Kerogen-Biosignatures-Origin of life-Archean-EPR spectroscopy. Astrobiology 13, 932-947.

Gourier D; Delpoux O; Binet L; Vezin H

2013-10-01

405

The nuclear matter bulk density in the droplet and Hartree-Fock models  

International Nuclear Information System (INIS)

[en] The predictions of the droplet (DM) and Hartree-Fock (HF) models for the nuclear matter density in the bulk region of finite nuclei are compared with experimental data. It is shown that the standard DM systematically underestimates the matter density in finite nuclei, this being mainly due to a bad fit of its parameters. The crucial role of the diffuseness and redistribution corrections to the DM is emphasised. These corrections strongly improve the agreement between HF and DM predictions when consistent sets of parameters are used. The systematic study of HF results also reveals deficiencies in the parametrisation of many HF effective interactions. For Skyrme-type forces of the standard form, with a reasonable compression modulus, we propose an improved estimation of the infinite nuclear matter saturation density, which is evaluated to 0.162 fm-3 +- 2%, i.e. ksub(F) = 1.34 fm-1. (orig.)

1984-01-01

406

Open charm tomography of cold and hot nuclear matter  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english We identify the nuclear effects that modify the cross sections for open heavy flavor production in proton-nucleus and nucleus-nucleus collisions. In p+A reactions, we calculate and resum the coherent nuclear-enhanced power corrections from the final-state parton scattering in the medium. We find 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 c (more) ollisions are also investigated. These lead to significantly weaker transverse momentum dependence of the nuclear attenuation and give a sizable contribution to the forward rapidity hadron suppression. In A+A reactions we revisit the question of the measured large heavy flavor quenching at RHIC. We derive the collisional broadening of the heavy meson's transverse momentum and the distortion of its intrinsic light cone wave function. The medium-induced dissociation probability of heavy mesons is shown to be sensitive to the opacity of the quark-gluon plasma and the time dependence of its formation and evolution. In contrast to previous results on heavy quark modification, our approach predicts suppression of B-mesons comparable to that of D-mesons at transverse momenta as low as pT ~ 10 GeV. It allows for an improved description of the large attenuation of non-photonic electrons in central Au+Au reactions at RHIC. Preliminary results in the implementation of collisional and radiative energy loss in a Langevin simulation approach to heavy quark diffusion and attenuation are also presented.

Vitev, Ivan

2007-06-01

407

The optical model potential of the $\\Sigma$ hyperon in nuclear matter  

CERN Multimedia

We present our attempts to determine the optical model potential $U_\\Sigma = V_\\Sigma -iW_\\Sigma$ of the $\\Sigma$ hyperon in nuclear matter. We analyze the following sources of information on $U_\\Sigma$: $\\Sigma N$ scattering, $\\Sigma^-$ atoms, and final state interaction of $\\Sigma$ hyperons in the $(\\pi,K^+)$ and $(K^-.\\pi)$ reactions on nuclear targets. We conclude that $V_\\Sigma$ is repulsive inside the nucleus and has a shallow a tractive pocket at the nuclear surface. These features of $V_\\Sigma$ are consistent with the Nijmegen model F of the hyperon-nucleon interaction.

Dabrowski, J

2009-01-01

408

Nuclear recoil energy scale in liquid xenon with application to the direct detection of dark matter  

Energy Technology Data Exchange (ETDEWEB)

We show for the first time that the quenching of electronic excitation from nuclear recoils in liquid xenon is well-described by Lindhard theory, if the nuclear recoil energy is reconstructed using the combined (scintillation and ionization) energy scale proposed by Shutt et al.. We argue for the adoption of this perspective in favor of the existing preference for reconstructing nuclear recoil energy solely from primary scintillation. We show that signal partitioning into scintillation and ionization is well-described by the Thomas-Imel box model. We discuss the implications for liquid xenon detectors aimed at the direct detection of dark matter.

Sorensen, P; Dahl, C E

2011-02-14

409

Instabilities in Nuclear and Neutron Matter at Subnuclear Densities  

International Nuclear Information System (INIS)

The development of the density and temperature inhomogeneities arising in collision of heavy ons is investigated by using the Landau equation involving a Skyrme-type interaction term. We discuss the mechanism of nuclear fragmentation as a result of these inhomogeneities. In recent years, the possible relations of nuclear fragmentation to the phase instabilities have been investigated by many authors. Comparison is made with the earlier works which involved various types of interaction functions. To perform the numerical calculations for instabilities we consider the Landau kinetic equation which is valid only at temperatures low compared with the Fermi temperature on the basis of Landau Fermi liquid theory. For the interaction function we have used an effective nucleon-nucleon interaction of the type developed by Skyrme. With a few reasonable assumptions we get our interaction function which is the same as that obtained by Vautherin and Brink. In the calculations we took the results of Ravenhall's parametrisation of Friedman and Pandharipande's calculations for Landau parameters. (author)

2000-09-08

410

Self consistent and covariant propagation of pions, nucleon and isobar resonances in cold nuclear matter  

Energy Technology Data Exchange (ETDEWEB)

We evaluate the in-medium spectral functions for pions, nucleon and isobar resonances in a self consistent and covariant manner. The calculations are based on a recently developed formulation which leads to predictions in terms of the pion-nucleon scattering phase shifts and a set of Migdal parameters describing important short range correlation effects. We do not observe significant softening of pion modes if we insist on reasonable isobar resonance properties but predict a considerable broadening of the N(1440) and N(1520) resonances in nuclear matter. Contrasted results are obtained for the s-wave N(1535) and N(1650) resonances which are affected by a nuclear environment very little. The properties of slowly moving isobar's in nuclear matter are found to depend very sensitively on a soft form factor in the {pi}NN vertex, which is not controlled by the {pi}N scattering data.

Korpa, C.L. [Department of Theoretical Physics, University of Pecs, Ifjusag u. 6, 7624 Pecs (Hungary); Lutz, M.F.M. [Gesellschaft fuer Schwerionenforschung (GSI), Planck Str. 1, D-64291 Darmstadt (Germany) and Institut fuer Kernphysik, TU Darmstadt, D-64289 Darmstadt (Germany)]. E-mail: m.lutz@gsi.de

2004-10-04

411

Microscopic study of thermal properties of the nuclear matter formed in heavy-ion collisions  

Energy Technology Data Exchange (ETDEWEB)

The hot Thomas-Fermi formalism, generalized for the case of two interpenetrating pieces of nuclear matter, is applied to investigate thermal properties (the local temperature and entropy) of the nonequilibrium nuclear matter formed during the time evolution of heavy-ion collisions at intermediate energies. Simulations of {sup 20}Ne+{sup 20}Ne, {sup 40}Ca+{sup 40}Ca and {sup 93}Nb+{sup 93}Nb collisions at E{sub lab}=100-400 MeV/u are performed within the framework of the quantum molecular dynamics approach. The sensitivity of thermal properties to the nuclear equation of state as well as their connection with some other dynamic observables are discussed. The anisotropic effects of the nonequilibrium phase space distribution on the thermalization process and the energy- and impact-parameter-dependence of the calculated thermal quantities during the reaction time are studied in detail. (orig.).

Khoa, D.T.; Ohtsuka, N.; Faessler, A.; Matin, M.A.; Huang, S.W.; Lehmann, E.; Lofty, Y. (Inst. fuer Theoretische Physik, Univ. Tuebingen (Germany))

1992-06-22

412

Microscopic study of thermal properties of the nuclear matter formed in heavy-ion collisions  

International Nuclear Information System (INIS)

[en] The hot Thomas-Fermi formalism, generalized for the case of two interpenetrating pieces of nuclear matter, is applied to investigate thermal properties (the local temperature and entropy) of the nonequilibrium nuclear matter formed during the time evolution of heavy-ion collisions at intermediate energies. Simulations of 20Ne+20Ne, 40Ca+40Ca and 93Nb+93Nb collisions at Elab=100-400 MeV/u are performed within the framework of the quantum molecular dynamics approach. The sensitivity of thermal properties to the nuclear equation of state as well as their connection with some other dynamic observables are discussed. The anisotropic effects of the nonequilibrium phase space distribution on the thermalization process and the energy- and impact-parameter-dependence of the calculated thermal quantities during the reaction time are studied in detail. (orig.)

1992-06-22

413

Probing the equation of state of nuclear matter via neutron star asteroseismology.  

UK PubMed Central (United Kingdom)

We general-relativistically calculate the frequency of fundamental torsional oscillations of neutron star crusts, where we focus on the crystalline properties obtained from macroscopic nuclear models in a way that is dependent on the equation of state of nuclear matter. We find that the calculated frequency is sensitive to the density dependence of the symmetry energy, but almost independent of the incompressibility of symmetric nuclear matter. By identifying the lowest-frequency quasiperiodic oscillation in giant flares observed from soft gamma-ray repeaters as the fundamental torsional mode and allowing for the dependence of the calculated frequency on stellar models, we provide a lower limit of the density derivative of the symmetry energy as L?50??MeV.

Sotani H; Nakazato K; Iida K; Oyamatsu K

2012-05-01

414

Cold Nuclear Matter Effects on Quarkonium Production from the SPS to the LHC  

International Nuclear Information System (INIS)

[en] The J/?, ?(prime) and ?c production yields are expected to be considerably suppressed in a quark-gluon plasma. In addition, the ? states, with the possible exception of the 1S state, are also expected to be suppressed. However, in proton-nucleus collisions all the quarkonium production cross sections scale less than linearly with the number of binary nucleon-nucleon collisions. These 'cold nuclear matter' effects need to be accounted for before signals of the high density QCD medium can be identified in the measurements made in nucleus-nucleus collisions. There are two cold nuclear matter effects important for midrapidity quarkonium production: 'nuclear absorption', a final-state effect, and shadowing, an initial-state effect. We characterize these effects and study their energy and rapidity dependence

2009-01-01

415

Cold Nuclear Matter Effects on J/psi Production: Intrinsic and Extrinsic Transverse Momentum Effects  

Energy Technology Data Exchange (ETDEWEB)

Cold nuclear matter effects on J/{psi} production in proton-nucleus and nucleus-nucleus collisions are evaluated taking into account the specific J/{psi}-production kinematics at the partonic level, the shadowing of the initial parton distributions and the absorption in the nuclear matter. We consider two different parton processes for the c{bar c}-pair production: one with collinear gluons and a recoiling gluon in the final state and the other with initial gluons carrying intrinsic transverse momentum. Our results are compared to RHIC observables. The smaller values of the nuclear modification factor R{sub AA} in the forward rapidity region (with respect to the mid rapidity region) are partially explained, therefore potentially reducing the need for recombination effects.

Ferreiro, E.G.; /Santiago de Compostela U.; Fleuret, F.; /Ecole Polytechnique; Lansberg, J.P.; /Heidelberg U.; Rakotozafindrabe, A.; /SPhN, DAPNIA, Saclay

2010-08-26

416

Signatures of dark matter burning in nuclear star clusters  

CERN Document Server

In order to characterize how dark matter (DM) annihilation inside stars changes the aspect of a stellar cluster we computed the evolution until the ignition of the He burning of stars from 0.7 to 3.5 M_sun within halos of DM with different characteristics. We found that, when a cluster is surrounded by a dense DM halo, the positions of the cluster' stars in the H-R diagram have a brighter and hotter turn-off point than in the classical scenario without DM, therefore giving the cluster a younger appearance. The high DM densities required to produce these effects are expected only in very specific locations, such as near the center of our Galaxy. In particular, if DM is formed by the 8 GeV WIMPs recently invoked to reconcile the results from direct detection experiments, then this signature is predicted for halos of DM with a density rho_DM = 3 \\cdot 10^5 GeV cm^3. A DM density gradient inside the stellar cluster would result in a broader main sequence, turn-off and red giant branch regions. Moreover, we found ...

Casanellas, Jordi

2011-01-01

417

Relativistic description of BCS-BEC crossover in nuclear matter  

CERN Multimedia

We study theoretically the di-neutron spatial correlations and the crossover from superfluidity of neutron Cooper pairs in the $^1S_0$ pairing channel to Bose-Einstein condensation (BEC) of di-neutron pairs for both symmetric and neutron matter in the microscopic relativistic pairing theory. We take the bare nucleon-nucleon interaction Bonn-B in the particle-particle channel and the effective interaction PK1 of the relativistic mean-field approach in the particle-hole channel. It is found that the spatial structure of neutron Cooper pair wave function evolves continuously from BCS-type to BEC-type as density decreases. We see a strong concentration of the probability density revealed for the neutron pairs in the fairly small relative distance around $1.5 {\\rm fm}$ and the neutron Fermi momentum $k_{Fn}\\in[0.6,1.0] {\\rm fm^{-1}}$. However, from the effective chemical potential and the quasiparticle excitation spectrum, there is no evidence for the appearance of a true BEC state of neutron pairs at any density....

Sun, Bao Yuan; Meng, Jie

2009-01-01

418

Investigating Biological Matter with Theoretical Nuclear Physics Methods  

CERN Multimedia

The internal dynamics of strongly interacting systems and that of biomolecules such as proteins display several important analogies, despite the huge difference in their characteristic energy and length scales. For example, in all such systems, collective excitations, cooperative transitions and phase transitions emerge as the result of the interplay of strong correlations with quantum or thermal fluctuations. In view of such an observation, some theoretical methods initially developed in the context of theoretical nuclear physics have been adapted to investigate the dynamics of biomolecules. In this talk, we review some of our recent studies performed along this direction. In particular, we discuss how the path integral formulation of the molecular dynamics allows to overcome some of the long-standing problems and limitations which emerge when simulating the protein folding dynamics at the atomistic level of detail.

Faccioli, Pietro

2011-01-01

419

Onset of nuclear matter expansion in Au+Au collisions  

CERN Multimedia

Using the FOPI detector at GSI Darmstadt, excitation functions of collective flow components were measured for the Au+Au system, in the reaction plane and out of this plane, at seven incident energies ranging from 100AMeV to 800AMeV. The threshold energies, corresponding to the onset of sideward-flow (balance energy) and squeeze-out effect (transition energy), are extracted from extrapolations of these excitation functions toward lower beam energies for charged products with Z>2. The transition energy is found to be larger than the balance energy. The impact parameter dependence of both balance and transition energies, when extrapolated to central collisions, suggests comparable although slightly higher values than the threshold energy for the radial flow. The relevant parameter seems to be the energy deposited into the system in order to overcome the attractive nuclear forces.

Crochet, Philippe; Gobbi, A; Donà, R; Coffin, J P; Fintz, P; Guillaume, G; Jundt, F; Kühn, C E; Roy, C; De Schauenburg, B; Tizniti, L; Wagner, P; Alard, J P; Amouroux, V; Andronic, A; Basrak, Z; Bastid, N; Belyaev, I; Best, D; Biegansky, J; Butà, A; Caplar, R; Cindro, N; Dupieux, P; Dzelalija, M; Fan, Z G; Fodor, Z; Fraysse, L; Freifelder, R P; Herrmann, N; Hildenbrand, K D; Hong, B H; Jeong, S C; Kecskeméti, J; Kirejczyk, M; Koncz, P; Korolija, M; Kotte, R; Lebedev, A; Leifels, Y; Man'ko, V I; Moisa, D; Mösner, J; Neubert, W; Pelte, D; Petrovici, M; Pinkenburg, C H; Pras, P; Ramillien, V; Reisdorf, W; Ritman, J L; Sadchikov, A G; Schüll, D; Seres, Z; Sikora, B; Simion, V; Siwek-Wilczynska, K; Sodan, U; Teh, K M; Trzaska, M; Vasilev, M A; Wang, G S; Wessels, J P; Wienold, T; Wisniewski, K; Wohlfarth, D; Zhilin, A V

1997-01-01

420

On the electrodynamical properties of nuclear matter in bulk  

International Nuclear Information System (INIS)

We analyze the properties of solutions of the relativistic Thomas-Fermi equation for globally neutral cores with radius of the order of R?10 Km, at constant densities around the nuclear density. By using numerical tecniques as well as well tested analytic procedures developed in the study of heavy ions, we confirm the existence of an electric field close to the critical value Ec = me2c3/e(?/2?) in a shell ?R?l04(?/2?)/m?c near the core surface. For a core of ?10 Km the difference in binding energy reaches 1049 ergs. These results can be of interest for the understanding of very heavy nuclei as well as physics of neutron stars, their formation processes and further gravitational collapse to a black hole.

2008-01-03

 
 
 
 
421

Surface effects on the energy gap in nuclear matter  

International Nuclear Information System (INIS)

The energy gap in the instrinsic excitation spectra of even-even nuclei is calculated in the BCS approximation starting from separable interactions adjusted to fit 1S0 nucleon scattering data. Simplified nuclear models are used to investigate the relation between the surface properties and the value of the energy gap in finite nuclei, and, in particular a slab model of infinite extent in two directions but finite in the third direction and of variable surface thickness is considered. An effective length of the slab is defined and this is held constant while the density profile is varied. For a fixed effective mass, it is found that the energy gap is essentially determined by the effective length for a particular interaction

1979-01-01

422

Particle production in hot and dense nuclear matter  

International Nuclear Information System (INIS)

The charged particle production in heavy ion reactions at 200 A GeV has been studied for projectiles of 16O and 32S on targets of Al, Cu, Ag and Au. Up to 700 charged particles are measured in the pseudorapidity region -1.7 32S+Au. The measured particle density is used to estimate the energy density attained in central collisions and gives a values of ?2 GeV/fm3. This is close to the energy density predicted for the phase transition from hadronic matter to a quark-gluon plasma. To measure the large number of charged particle produced, finely granulated detector systems are employed. Streamer tube detectors with pad readout and large area, multi-step avalanche chambers with optical readout have been developed for the measurements. The widths of the pseudorapidity distributions of charged particles increase with decreasing centrality of the collision as well as with increasing mass of the target nucleus. This behaviour is assumed to be due to the target fragmentation. The Monte-Carlo model for nucleus-nucleus collisions, VENUS 3.11, which includes rescattering, is in reasonable agreement with the data. The yield of charged particles for central collisions of the heavy targets with 33S is found to be proportional to the target mass, A, at target rapidity. At midrapidity it is approximately proportional to A0.3. At midrapidity the charged particle measurements are supplemented by measurements of the transverse energy. The dimensionless, normalized variances of the multiplicity and transverse energy distributions are, to a large extent, governed by the collision geometry. The change in the normalized variance when studying the charged particle distribution in a narrow angular region is explained as being of statistical nature. (au)

1992-01-01

423

Application of effective field theory on nuclear matter and neutron matter; Anwendung effektiver Feldtheorie auf Kernmaterie und Neutronenmaterie  

Energy Technology Data Exchange (ETDEWEB)

In the thesis the effective field theory in NLO and NNLO order is applied. The order NLO still knows no three-particle forces. The theory yields however already in this order the saturation behaviour of nuclear matter. This is due to the fact that in the NLO order the scattering phases are qualitatively correctly reproduced, especially the scattering phases {sup 1}S{sub 0} and {sup 3}S{sub 1} are for energies above 200 MeV negative, which is in all potentials by a so called hard core represented. In the NNLO orde three-particle forces occur, which lead to a larger improvement of the saturation curve, however the saturation point lies still at too high densities. A correction of the low-energy constants by scarcely three percent of the value in the vacuum generates however a saturation curve, which reproduces the empirical binding energy per particle, the density and the compressibility of nuclear matter. About the equation of state of neutron matter is empirically few known. At small densities of neutron matter (k{sub f}<1 fm{sup -1}) the NLO and NNLO orders scarcely differ, but indeed from the free Fermi gas. For applications in finite nuclei a simplified parametrization of the nucleon-nucleon interactions was developed, which reproduces both the known scattering phases with an NLO-comparable accuracy and the empirical saturation behaviour. [German] In der Arbeit wird die Effektive Feldtheorie in der Ordnung NLO und NNLO angewandt. Die Ordnung NLO kennt noch keine Dreiteilchenkraefte. Die Theorie liefert jedoch bereits in dieser Ordnung das Saettigungsverhalten von Kernmaterie. Dies liegt daran, dass bereits in der Ordnung NLO die Streuphasen qualitativ korrekt reproduziert werden, insbesondere sind die Streuphasen {sup 1}S{sub 0} und {sup 3}S{sub 1} fuer Energien oberhalb 200 MeV negativ, was in allen Potentialen durch einen sogenannten ''hard core'' dargestellt wird. In der Ordnung NNLO treten Dreiteilchenkraefte auf, die zu einer grossen Verbesserung der Saettigungskurve fuehren, jedoch liegt der Saettigungspunkt immer noch bei zu hohen Dichten. Eine Korrektur der Niederenergiekonstanten um knapp drei Prozent des Wertes im Vakuum erzeugt jedoch eine Saettigungskurve, die die empirische Bindungsenergie pro Teilchen, die Dichte und die Kompressibilitaet von Kernmaterie reproduziert. Ueber die Zustandsgleichung von Neutronenmaterie ist empirisch wenig bekannt. Bei kleinen Dichten von Neutronenmaterie (k{sub f}<1 fm{sup -1}) unterscheiden sich die Ordnungen NLO und NNLO kaum von einander, wohl aber vom freien Fermigas. Fuer Anwendungen in endlichen Kernen wurde eine vereinfachte Parametrisierung der Nukleon-Nukleon Wechselwirkung entwickelt, die sowohl die bekannten Streuphasen mit einer NLO-vergleichbaren Genauigkeit als auch das empirische Saettigungsverhalten reproduziert. (orig.)

Saviankou, Pavel

2009-05-15

424

Methods of investigation of nuclear matter under the conditions characteristics for transition to quark-gluon plasma  

CERN Multimedia

Features of deep inelastic nuclear reactions proceeding on dense fluctuations of nuclear matter (fluctons) are briefly considered. Fluctons, which can be many-quark bags or drops of quark-gluon plasma, are studied. Their properties are discussed, viz., characteristic parameters of nuclear matter inside a flucton - temperature and density close to the critical values for a phase transition. These values can be reached or exceeded if the flucton-flucton collision events are separated. The separation method is discussed

Leksin, G A

2002-01-01

425

On the Quantized Relativistic Mean Field Theory for Nuclear Matter  

CERN Document Server

We propose a quantization procedure for the nucleon-scalar meson system, in which an arbitrary mean scalar meson field $\\phi$ is introduced. The equivalence of this procedure with the usual ones is proven for any given value of $\\phi$. By use of this procedure, the scalar meson field in the Walecka's RMFT and in Chin's RHA are quantized around the mean field. Its corrections on these theories are considered by perturbation up to the second order. The arbitrariness of $\\phi$ makes us free to fix it at any stage in the calculation. When we fix it in the way of Walecka's RMFT, the quantum corrections are big, and the result does not converge. When we fix it in the way of Chin's RHA, the quantum correction is negligibly small, and the convergence is excellent. It shows that RHA covers the leading part of quantum field theory for nuclear systems and is an excellent zeroth order approximation for further quantum corrections, while the Walecka's RMFT does not. We suggest to fix the parameter $\\phi$ at the end of the...

Zhang, Qi-Ren

2010-01-01

426

Field theoretical model for nuclear and neutron matter. II. Neutron stars  

Energy Technology Data Exchange (ETDEWEB)

We analyze the consequences on relativistic stellar configurations of two new equations of state (EOS) for neutron matter by taking into account the more recent observational evidence. The EOS have been obtained by solving a general field (Lagrangian) theoretical model for nuclear interaction which contains many models studied in the literature as particular cases. The model describes an assembly of nucleons interacting via scalar (sigma) mesons, pions (..pi..), and vector (..omega.. and rho) mesons; it is solved in the renormalized Hartree approximation, and the relativistic effects are included. The first resulting EOS (EOS I) comes from a particular determination of the free parameters in the Serot model, gives a satisfactory description of the saturation properties of symmetric nuclear matter and of the symmetry energy at nuclear density, and can be accurately matched to the Baym-Bethe-Pethick EOS at a density of approx.8 x 10/sup 12/ g cm/sup -3/. The nuclear incompressibility (460 MeV) is too high in this case. The second EOS (EOS II) comes from a determination of the free parameters of the linear sigma-model with an explicit symmetry breaking term and is coupled to the ..omega.. and rho mesons in a renormalizable way. This EOS reproduces accurately the properties of symmetric nuclear matter at nuclear density and, in particular, gives a nuclear incompressibility of 225 MeV. We present the configurations which result when solving the general relativistic stellar structure equations with both EOS I and II and, for the sake of comparison, with the Chin and the so-called Canuto EOS. EOS I and II lead to equilibrium configurations compatible with the present status of observational evidence.

Alonso, J.D.; Ibnez Cabanell, J.M.

1985-04-01

427

Quark-Meson Coupling Model, Nuclear Matter Constraints and Neutron Star Properties  

CERN Multimedia

We explore the equation of state for nuclear matter in the quark-meson coupling model, including full Fock terms. The comparison with phenomenological constraints can be used to restrict the few additional parameters appearing in the Fock terms which are not present at Hartree level. Because the model is based upon the in-medium modification of the quark structure of the bound hadrons, it can be applied without additional parameters to include hyperons and to calculate the equation of state of dense matter in beta-equilibrium. This leads naturally to a study of the properties of neutron stars, including their maximum mass, their radii and density profiles.

Whittenbury, D L; Thomas, A W; Tsushima, K; Stone, J R

2013-01-01

428

The effect of isoscalar–isovector coupling in infinite nuclear matter  

Science.gov (United States)

In the framework of relativistic mean field theory, we study the effect of nonlinear cross coupling between the isoscalar–vector and isovector–vector mesons on top of G2 parametrization. The energy and pressure densities are calculated over a wide range of baryon densities. The observables such as symmetry energy and related coefficients are also evaluated systematically. The effect of cross coupling on the symmetry energy of symmetric nuclear matter is studied. The work is further extended to ?-equilibrium matter to estimate the mass and radius of neutron stars and also to the baryon octet to see the effect of coupling over the equation of state.

Singh, S. K.; Bhuyan, M.; Panda, P. K.; Patra, S. K.

2013-08-01

429

Mass of {omega} meson in the nuclear matter; Masse du meson {omega} dans la matiere nucleaire  

Energy Technology Data Exchange (ETDEWEB)

General symmetry arguments (the sum QCD rules) predict that the effective mass of the {omega} and {sigma} mesons in the nuclear matter must diminish as against their free space values, when the baryonic density increases. It seems interesting to study the modifications of the meson masses in a baryonic medium by explicitly calculation of the poles (in the like-time region) of the dressed meson propagations. Since the mesons can be coupled to nucleons by polarization processes i.e. by density fluctuations, their masses must be sensible to the nuclear matter compressibility. Actually, by using the relativistic Hartree approximation which overestimates the incompressibility module (K = 500 MeV), we have obtained an {omega} meson mass value which decreases practically linearly with the density as against its free value. In contradistinction, by using for this calculation a density-dependent relativistic NN interaction, as given by a Dirac-Brueckner model, which reproduces correctly the nuclear matter compressibility (K = 250 MeV), we have equally observed a decrease in the {omega} meson mass in the nuclear environment.But this mass appears to be constant, independently of the density value as long as it is higher than 20% of saturation density. Experiments of determining the {omega} mass should be soon realized at TJNAF (late CEBAF) and these are expected to show at which extent our description is realistic

Caillon, J-C.; Labarsouque, J. [Centre d`Etudes Nucleaires, Bordeaux-1 Univ., 33 Gradignan (France)

1997-06-01

430

Density dependencies of interaction strengths and their influence on nuclear matter and neutron star in relativistic mean field theory  

CERN Document Server

The density dependencies of various effective interaction strengths in the relativistic mean field are studied and carefully compared for nuclear matter and neutron stars. The influences of different density dependencies are presented and discussed on mean field potentials, saturation properties for nuclear matter, equations of state, maximum masses and corresponding radii for neutron stars. Though the interaction strengths and the potentials given by various interactions are quite different in nuclear matter, the differences of saturation properties are subtle, except for NL2 and TM2, which are mainly used for light nuclei, while the properties by various interactions for pure neutron matter are quite different. To get an equation of state for neutron matter without any ambiguity, it is necessary to constrain the effective interactions either by microscopic many-body calculations for the neutron matter data or the data of nuclei with extreme isospin. For neutron stars, the interaction with large interaction ...

Ban, S F; Zhang, S Q; Jia, H Y; Sang, J P; Meng, J

2004-01-01

431

Investigation of hot dilute and hot compressed nuclear matter  

Science.gov (United States)

Breakup temperatures were determined for the 197Au+197Au collisions at E/A = 35 MeV and the 129Xe+natCu collisions at E/A = 30 MeV from the relative populations of excited states of 5Li, 4He and 10B fragments and nine double ratios involving the yields of elements with 1/le Z/le6. These two experiments were measured from the Miniball-Multics array. Unlike results reported at significantly higher energies, all thermometers for these two experiments yield temperatures that are consistent within the experimental uncertainties. Extrapolation of the data for the 197Au+197Au reactions to zero impact parameter yields Tem=4.6/pm0.4/ MeV, 1.5 MeV lower than the temperature assumed in Statistical Multifragmentation Model calculations which describe most of the other features of this reaction. For 129Xe+natCu reactions, the breakup temperature for zero impact parameter was also extrapolated and yields T/sb [em]=3.9/pm0.4/ MeV. The number was then compared with BUU calculations and the breakup temperature is shown to favor the soft equation of state before the cooling correction. For another experiment, 84Kr+197Au collisions at E/A = 200 MeV, directed transverse fragment flow was extracted by using techniques that are free of reaction plane dispersion. The fragment flow per nucleon increases with mass, following a thermal- or coalescence- like behavior, and attains roughly constant limiting values at 4/le A/le 12. Comparisons of the impact parameter dependences of the measured coalescence- invariant proton flow to Boltzmann-Uehling-Uhlenbeck calculations clearly favor a momentum dependent nuclear mean field.

Huang, Min-Jui

432

Bell-shaped nuclei dividing by symmetrical and asymmetrical nuclear fission have qualities of stem cells in human colonic embryogenesis and carcinogenesis.  

UK PubMed Central (United Kingdom)

Large cell nuclei with at least eight distinct morphologies have been discovered throughout the fetal gut (5-7 weeks), colonic adenomas, and adenocarcinomas, five of which are not present in the normal adult colon. The most remarkable nuclear forms are hollow bells, approximately 10-15 microns in height and about 7-10 microns in bell mouth diameter. When encased in tubular syncytia, these bell-shaped structures divide symmetrically by an amitotic nuclear fission process resembling the separation of two paper cups. Seven other nuclear morphotypes emerge from the bell-shaped nuclei within the syncytia by asymmetrical amitotic nuclear fission. Cells containing these differentiated nuclear forms subsequently divide extra-syncytially by mitoses that form clonal populations of cells with identical nuclear morphotypes in embryos, adenomas, adenocarcinomas, and metastases. Cells with bell-shaped nuclei thus appear to be responsible for both net growth and differentiation in the embryonic gut, adenomas, and adenocarcinomas, and fulfill the requirements for post-embryonic stem cells in colon organogenesis and carcinogenesis.

Gostjeva EV; Zukerberg L; Chung D; Thilly WG

2006-01-01

433

Bell-shaped nuclei dividing by symmetrical and asymmetrical nuclear fission have qualities of stem cells in human colonic embryogenesis and carcinogenesis.  

Science.gov (United States)

Large cell nuclei with at least eight distinct morphologies have been discovered throughout the fetal gut (5-7 weeks), colonic adenomas, and adenocarcinomas, five of which are not present in the normal adult colon. The most remarkable nuclear forms are hollow bells, approximately 10-15 microns in height and about 7-10 microns in bell mouth diameter. When encased in tubular syncytia, these bell-shaped structures divide symmetrically by an amitotic nuclear fission process resembling the separation of two paper cups. Seven other nuclear morphotypes emerge from the bell-shaped nuclei within the syncytia by asymmetrical amitotic nuclear fission. Cells containing these differentiated nuclear forms subsequently divide extra-syncytially by mitoses that form clonal populations of cells with identical nuclear morphotypes in embryos, adenomas, adenocarcinomas, and metastases. Cells with bell-shaped nuclei thus appear to be responsible for both net growth and differentiation in the embryonic gut, adenomas, and adenocarcinomas, and fulfill the requirements for post-embryonic stem cells in colon organogenesis and carcinogenesis. PMID:16364758

Gostjeva, E V; Zukerberg, L; Chung, D; Thilly, W G

2006-01-01

434

Cold Nuclear Matter effects in Upsilon production in dAu collisions at RHIC  

CERN Document Server

We report on our recent study of Cold Nuclear Matter effects on the Upsilon production at RHIC in dAu collisions. The first experimental results available on the nuclear modification factor R_dAu have rather large uncertainties. They nevertheless allow to bring qualitative information on the nature of the nuclear effects at play on top of the usual nuclear absorption, since the latter is expected to lie in a quite small range around a value close to ten times smaller as for charmonia. At backward rapidities, the behavior of R_dAu hints at the presence of a gluon EMC effect, analogous to the quark EMC effect -- but possibly stronger. Mid rapidity measurements with a better precision are highly desirable to pin down the gluon anti-shadowing, still under debate. At forward rapidities, the data leave some room for an additional fractional energy loss mechanism, recently revived in the literature.

Rakotozafindrabe, Andry; Fleuret, Frédéric; Lansberg, Jean-Philippe; Matagne, Nicolas

2012-01-01

435

The Equation of State of Dense Matter : from Nuclear Collisions to Neutron Stars  

CERN Document Server

The Equation of State (EoS) of dense matter represents a central issue in the study of compact astrophysical objects and heavy ion reactions at intermediate and relativistic energies. We have derived a nuclear EoS with nucleons and hyperons within the Brueckner-Hartree-Fock approach, and joined it with quark matter EoS. For that, we have employed the MIT bag model, as well as the Nambu--Jona-Lasinio (NJL) and the Color Dielectric (CD) models, and found that the NS maximum masses are not larger than 1.7 solar masses. A comparison with available data supports the idea that dense matter EoS should be soft at low density and quite stiff at high density.

Burgio, Fiorella

2008-01-01

436

Risk assessment model for nuclear accident emergency protection countermeasure based on fuzzy matter-element analysis  

International Nuclear Information System (INIS)

A risk assessment model of nuclear accident emergency protection countermeasure based on fuzzy matter-element analysis and Euclid approach degree is proposed in the paper. The weight of assessed index is determined by information entropy and the scoring by experts, which could not only make full use of the inherent information of the indexes adequately, but reduce subjective assumption in the course of assessment effectively. The applied result shows that it is reasonable that the model is adopted to make risk assessment for nuclear accident emergency protective countermeasure,and it could be a kind of effective analytical method and decision making basis to choose the optimum protection countermeasure. (authors)

2009-01-01

437

From chiral Lagrangians to Landau Fermi liquid theory of nuclear matter  

International Nuclear Information System (INIS)

A simple relation between the effective parameters of chiral Lagrangians in medium as predicted by BR scaling and Landau Fermi liquid parameters is derived. This provides a link between an effective theory of QCD at mean-field level and many-body theory of nuclear matter. It connects in particular the scaling vector-meson mass probed by dileptons produced in heavy-ion collisions (e.g., CERES of CERN-SPS) to the scaling nucleon-mass relevant for low-energy spectroscopic properties, e.g., the nuclear gyromagnetic ratios ?g1 and the effective axial-vector constant g*A. (orig.)

1996-01-01

438

Natural orbitals representation and Fermi sea depletion in finite nuclei and nuclear matter  

CERN Document Server

The natural orbitals and natural occupation numbers of various N = Z, sp and sd shell nuclei are calculated by applying a correlated one-body density matrix. The correlated density matrix has been evaluated by considering central correlations of Jastrow type and an approximation named factor cluster expansion. The correlation effects on the natural orbitals, natural occupation numbers and the Fermi sea depletion are discussed and analysed. In addition, an approximate expression for the correlated one-body density matrix of the nuclear matter has been used for the evaluation of the relative momentum distribution and the Fermi sea depletion. We found that the value of the Fermi sea depletion is higher in closed shell nuclei compared to open shell ones and it is lower compared to the case of nuclear matter. This statement could be confirmed by relevant experimental studies.

Psonis, V P; Massen, S E

2013-01-01

439

Dirac-Brueckner mean fields and the effective Dirac-Hartree-Fock interaction in nuclear matter  

Science.gov (United States)

Our objective is to include Fock exchange terms, and thus the pion, in a Dirac description of nuclear matter and to determine a density-dependent Dirac-Hartree-Fock meson exchange interaction that is hopefully less density-dependent than a typical Hartree one. We begin by performing extended self-consistent nuclear matter Dirac-Brueckner calculations over a wide range of densities and asymmetries. We maintain the momentum dependence of the Brueckner mean fields in the hope of fitting it with the momentum dependence of the effective Dirac-Hartree-Fock mean fields. To improve the description of the Brueckner mean fields within a Hartee-Fock approximation, we include contact terms in the interaction.

Carlson, B. V.; Hirata, D.

2010-02-01

440

Dirac-Brueckner mean fields and the effective Dirac-Hartree-Fock interaction in nuclear matter  

International Nuclear Information System (INIS)

[en] Our objective is to include Fock exchange terms, and thus the pion, in a Dirac description of nuclear matter and to determine a density-dependent Dirac-Hartree-Fock meson exchange interaction that is hopefully less density-dependent than a typical Hartree one. We begin by performing extended self-consistent nuclear matter Dirac-Brueckner calculations over a wide range of densities and asymmetries. We maintain the momentum dependence of the Brueckner mean fields in the hope of fitting it with the momentum dependence of the effective Dirac-Hartree-Fock mean fields. To improve the description of the Brueckner mean fields within a Hartee-Fock approximation, we include contact terms in the interaction.

2010-01-01