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1

Incompressibility in asymmetric nuclear matter

International Nuclear Information System (INIS)

The study of nuclear equation of state (EOS) of asymmetric nuclear matter is a subject of major research over the last decade for its crucial importance in understanding the mechanism of supernova explosion, neutron star formation and heavy-ion (HI) collision studies at high energies. In this work EOS of asymmetric nuclear matter in the mean field approximation using a finite range effective interaction having Yukawa form is studied

2

Spinodal in asymmetric nuclear matter

International Nuclear Information System (INIS)

The phase diagram of nuclear matter is quite rich; it shows such phenomena as phase-transitions, formation of condensates, clustering, etc. >From the analysis of the spinodal instability, one can learn about the region of liquid-gas coexistence in nuclear matter at low densities and finite isospin asymmetries. In a recent paper, we have shown that asymmetric nuclear matter at sub-nuclear densities should undergo only one type of instability. The associated order parameter is dominated by the isoscalar density and so the transition is of liquid-gas type. The instability goes in the direction of a restoration of the isospin symmetry leading to a fractionation phenomenon. The nuclear interaction is very similar to the Van der Waals potential which acts between molecules. For this reason, below saturation density, the nuclear interaction is also expected to lead to a liquid-gas phase transition. Recently, a converging ensemble of experimental signals seems to have established the phase transition. One is the spinodal decomposition which considers volume instabilities (domain of negative incompressibility). One expects that the system which enters such a forbidden region will favorably breakup into nearly equally-sized 'primitive' fragments in relation to the wavelengths of the most unstable modes. How the simple picture is modified by the asymmetry charge and whether we can expect new signals related to the collision of very asymmetric nuclei are the questions which the aetric nuclei are the questions which the author finally poses. (author)

3

Effective mass in asymmetric nuclear matter

International Nuclear Information System (INIS)

The momentum and temperature dependence of effective mass has been studied in symmetric nuclear matter by using finite range interactions in an earlier work. The study is now extended to the case of asymmetric nuclear matter

4

Isospin-asymmetric nuclear matter

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

López, J A; González, R; Ravelo, R

2013-01-01

5

Droplet formation in cold asymmetric nuclear matter

An extended version of the non-linear Walecka model, with [varrho] mesons an electromagnetic field is used to investigate the possibility of phase transitions in cold nuclear matter (T = 0), giving rise to droplet formation. Surface properties of asymmetric nuclear matter as the droplet surface energy and its thickness are discussed. The effects of the Coulomb interaction are investigated.

Menezes, D. P.; Provide?ncia, C.

1999-01-01

6

Nucleation Process in Asymmetric Nuclear Matter

An extended version of the non linear Walecka model, with rho mesons and eletromagnetic field is used to investigate the possibility of phase transitions in hot (warm) nuclear matter, giving rise to droplet formation. Surface properties of asymmetric nuclear matter as the droplet surface energy and its thickness are also examined.

Peres-Menezes, D

1998-01-01

7

Thermal Properties of Asymmetric Nuclear Matter

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

Fedoseew, Andreas

2014-01-01

8

Symmetry energy coefficients for asymmetric nuclear matter

Symmetry energy coefficients of asymmetric nuclear matter are investigated as the inverse of nuclear matter polarizabilities with two different approaches. Firstly a general calculation shows they may depend on the neutron-proton asymmetry itself. The choice of particular prescriptions for the density fluctuations lead to certain isospin (n-p asymmetry) dependences of the polarizabilities. Secondly, with Skyrme type interactions, the static limit of the dynamical polarizabil...

Braghin, Fa?bio L.

2003-01-01

9

Compression modulus of asymmetric nuclear matter

International Nuclear Information System (INIS)

The formula for the compression modulus of asymmetric nuclear matter is derived within the framework of the Landau theory of normal Fermi liquids. The net effect of neutron excess is to make nuclear matter at a fixed density rho=rhosub(n)+rhosub(p) more incompressible. The increase in the compression modulus is well described by the formula Ksub(e)?2, with ?=(rhosub(n)-rhosub(p))/rho and Ksub(e) approximately 270 MeV. When the compression modulus is calculated at the equilibrium density of asymmetric nuclear matter, the net increase reads Ksub(e)sup(eq)?2, with Ksub(e)sup(eq) approximately 150 MeV. In the case of strongly asymmetric nuclear matter (rhosub(p)<< rho) corresponding to the liquid interior of neutron stars, the effect of admixture of protons is to make the matter more compressible, as compared to the pure neutron matter case, the decrease of the compression modulus being proportional to the proton fraction. (Auth.)

10

Isobaric incompressibility of isospin asymmetric nuclear matter

International Nuclear Information System (INIS)

The isospin dependence of the saturation properties of asymmetric nuclear matter, particularly the incompressibility K?(X)=K?+K?X2+O(X4) at saturation density, is systematically studied using density-dependent M3Y interaction. K? characterizes the isospin dependence of the incompressibility at saturation density ?0. The approximate expression Kasy?Ksym-6L is often used for K? where L and Ksym represent the slope and curvature parameters of the symmetry energy at ?0, respectively. It can be expressed accurately as K?=Ksym-6L-(Q0/K?)L, where Q0 is the third-order-derivative parameter of symmetric nuclear matter at ?0. The results of this addendum to [Phys. Rev. C 80, 011305(R) (2009)] indicate that the Q0 contribution to K? is not insignificant.

11

Equation of state of asymmetric nuclear matter

International Nuclear Information System (INIS)

The equation of state (EOS) of asymmetric nuclear matter (N? Z) has been calculated by using finite range phenomenological effective interaction. Various thermodynamical quantities such as free energy density, pressure, entropy density, chemical potential etc. are obtained as a function of density and temperature for given asymmetry in the neutron and proton numbers. As an application, the EOS is used to calculate the phase transition to quark-gluon plasma (QGP) and the probable effect of the asymmetry in neutron and proton numbers on the transition temperature is examined

12

Topological phase transition in asymmetric nuclear matter

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

Phat, Tran Huu; Thu, Nguyen Van

2014-05-01

13

Pseudo-Goldstone modes in isospin-asymmetric nuclear matter

International Nuclear Information System (INIS)

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

14

Higher order bulk characteristic parameters of asymmetric nuclear matter

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

Chen, Lie-wen

2011-01-01

15

Damping of giant resonances in asymmetric nuclear matter

Energy Technology Data Exchange (ETDEWEB)

The giant collective modes in asymmetric nuclear matter are investigated within a dynamic relaxation time approximation. We derive a coupled dispersion relation and show that two sources of coupling appear: (i) a coupling of isoscalar and isovector modes due to different mean-fields acting and (ii) an explicit new coupling in asymmetric matter due to collisional interaction. We show that the latter one is responsible for a new mode arising besides isovector and isoscalar modes.

Morawetz, K.; Fuhrmann, U.; Walke, R

1999-03-29

16

Asymmetric nuclear matter based on chiral effective field theory interactions

Energy Technology Data Exchange (ETDEWEB)

We investigate the properties of asymmetric nuclear matter with small proton fractions (high asymmetries). Our calculations are based on two- and three-nucleon forces from chiral effective field theory. We compare our microscopic results, including theoretical uncertainties, to a quasi-parabolic approximation developed to interpolate between pure neutron and symmetric nuclear matter. Our investigations are important for neutron-rich matter in astrophysics and as constraints for energy density functionals.

Drischler, Christian; Soma, Vittorio [Technische Univ. Darmstadt (Germany). Inst. fuer Kernphysik; GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany). ExtreMe Matter Institute EMMI; Schwenk, Achim [GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany). ExtreMe Matter Institute EMMI; Technische Univ. Darmstadt (Germany). Inst. fuer Kernphysik

2013-07-01

17

Liquid-gas phase transition in asymmetric nuclear matter

International Nuclear Information System (INIS)

Liquid-gas phase transition in nuclear matter and in finite nuclei has been a subject of major interest in recent years. The Van-der-waal's behavior of pressure P versus density ? (or, equivalently chemical potential ? versus ?) is typical of a liquid gas phase transition and the critical temperature Tc is determined at which the isotherm has an inflection point. In the present work it is planned to study the liquid-gas phase transition in asymmetric nuclear matter as well as in finite nuclear systems in the framework of mean field theory using a finite range effective interaction

18

Strange particles in asymmetric nuclear matter

Energy Technology Data Exchange (ETDEWEB)

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

Akaishi, Yoshinori [High Energy Accelerator Research Organization, Institute of Particle and Nuclear Studies, Tsukuba, Ibaraki (Japan)

2002-09-01

19

Asymmetric Colliding Nuclear Matter Approach in Heavy Ion Collisions

The early stage of a heavy ion collision is governed by local non-equilibrium momentum distributions which have been approximated by colliding nuclear matter configurations, i.e. by two Lorentz elongated Fermi ellipsoids. This approach has been extended from the previous assumption of symmetric systems to asymmetric 2-Fermi sphere configurations, i.e. to different densities. This provides a smoother transition from the limiting situation of two interpenetrating currents to an equilibrated system. The model is applied to the dynamical situations of heavy ion collisions at intermediate energies within the framework of relativistic transport (RBUU) calculations. We find that the extended colliding nuclear matter approach is more appropriate to describe collective reaction dynamics in terms of flow observables, in particular, for the elliptic flow at low energies.

Gaitanos, T; Wolter, H H

2004-01-01

20

Response of asymmetric nuclear matter to isospin-flip probes

We investigate the RPA response of asymmetric nuclear matter to external fields which induce charge exchange between nucleons, both at zero and finite temperature. Closed expressions are obtained for the RPA response in each spin channel when the nucleon-nucleon interaction is of the Skyrme type. Exchange terms are fully taken into account. We consider the transferred momentum, asymmetry and temperature as the relevant parameters of our study. Special emphasis is given to the role of neutron excess in relation to the collective states at low momentum.

Hernández, E S; Polls, A

1999-01-01

21

Differential isospin-fractionation in dilute asymmetric nuclear matter

International Nuclear Information System (INIS)

The differential isospin-fractionation (IsoF) during the liquid-gas phase transition in dilute asymmetric nuclear matter is studied as a function of nucleon momentum. Within a self-consistent thermal model it is shown that the neutron/proton ratio of the gas phase becomes smaller than that of the liquid phase for energetic nucleons, although the gas phase is overall more neutron-rich. Clear indications of the differential IsoF consistent with the thermal model predictions are demonstrated within a transport model for heavy-ion reactions. Future comparisons with experimental data will allow us to extract critical information about the momentum dependence of the isovector strong interaction

22

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

International Nuclear Information System (INIS)

60Ca + 60Ca and 197Au + 197Au collisions are studied with an extended version Antisymmetrized Molecular Dynamics (AMD-V), in order to investigate whether the reaction observables carry the information of the equation of state of the asymmetric nuclear matter. (author)

23

Surface characteristics of semi-infinite asymmetric nuclear matter at low temperature

International Nuclear Information System (INIS)

For applying to semi-infinite asymmetric nuclear matter, simple analytical relations for the surface and surface symmetry energies and their evolution with temperature using a number of Skyrme interactions are obtained. (M.G.B.)

24

Propagation of neutral mesons in asymmetric nuclear matter

We calculate dispersion relations and propagators for the $\\sigma$, $\\omega$, $\\rho$ and $\\delta$ mesons in relativistic nuclear matter with a proton-neutron asymmetry. In addition to the $\\sigma$-$\\omega$ and $\\delta$-$\\rho$ mixings already present in symmetric matter, mixing occur between all components of the $\\sigma$-$\\omega$-$\\delta$-$\\rho$ system when the proton fraction differs from 1/2.

Mornas, L

2001-01-01

25

Nuclear mean field and equation of state of asymmetric nuclear matter

Energy Technology Data Exchange (ETDEWEB)

Neutron and proton mean field properties and equation of state of highly isospin asymmetric dense nuclear matter are studied using simple finite range effective interactions. The density dependence of nuclear symmetry energy is constrained on the basis of an approximate universal high density behaviour of asymmetric contribution to the nucleonic part of energy density of infinite n+p+e+{mu} matter in beta-equilibrium. Recently discovered astrophysical bounds from neutron star mass measurements and cooling phenomenology as well as informations coming from optical model analysis of nucleon-nucleus scattering data at intermediate energies, transport model analysis of flow data in heavy ion collisions and monopole mode of vibrations in finite nuclei have also been used to constrain the interaction parameters involved.

Behera, B. [Department of Physics, Sambalpur University, Sambalpur 768019, Orissa (India); Routray, T.R. [Department of Physics, Sambalpur University, Sambalpur 768019, Orissa (India)], E-mail: trr1@rediffmail.com; Pradhan, A. [Department of Physics, Sambalpur University, Sambalpur 768019, Orissa (India); Patra, S.K.; Sahu, P.K. [Institute of Physics, Sachivalaya Marg, Bhubaneswar 751005, Orissa (India)

2007-10-01

26

Nuclear mean field and equation of state of asymmetric nuclear matter

International Nuclear Information System (INIS)

Neutron and proton mean field properties and equation of state of highly isospin asymmetric dense nuclear matter are studied using simple finite range effective interactions. The density dependence of nuclear symmetry energy is constrained on the basis of an approximate universal high density behaviour of asymmetric contribution to the nucleonic part of energy density of infinite n+p+e+? matter in beta-equilibrium. Recently discovered astrophysical bounds from neutron star mass measurements and cooling phenomenology as well as informations coming from optical model analysis of nucleon-nucleus scattering data at intermediate energies, transport model analysis of flow data in heavy ion collisions and monopole mode of vibrations in finite nuclei have also been used to constrain the interaction parameters involved

27

From asymmetric nuclear matter to neutron stars: a functional renormalization group study

A previous study of nuclear matter in a chiral nucleon-meson model is extended to isospin-asymmetric matter. Fluctuations beyond mean-field approximation are treated in the framework of the functional renormalization group. The nuclear liquid-gas phase transition is investigated in detail as a function of the proton fraction in asymmetric matter. The equations of state at zero temperature of both symmetric nuclear matter and pure neutron matter are found to be in good agreement with realistic many-body computations. We also study the density dependence of the pion mass in the medium. The question of chiral symmetry restoration in neutron matter is addressed; we find a stabilization of the phase with spontaneously broken chiral symmetry once fluctuations are included. Finally, neutron star matter including beta equilibrium is discussed. The model satisfies the constraints imposed by the existence of two-solar-mass neutron stars.

Drews, Matthias

2014-01-01

28

International Nuclear Information System (INIS)

Using the Hugenholtz-Van Hove theorem, we derive general expressions for the quadratic and quartic symmetry energies in terms of the isoscalar and isovector parts of single-nucleon potentials in isospin asymmetric nuclear matter. These expressions are useful for gaining deeper insights into the microscopic origins of the uncertainties in our knowledge on nuclear symmetry energies especially at supra-saturation densities. As examples, the formalism is applied to two model single-nucleon potentials that are widely used in transport model simulations of heavy-ion reactions.

29

Properties of hot dense asymmetric nuclear matter in the relativistic density functional theory

International Nuclear Information System (INIS)

In recent years there has been increased interest in the study of hot nuclear matter and neutron matter. The properties of dense and finite-temperature asymmetric nuclear matter are of great interest in the studies of the dynamics of heavy-ion collisions, stellar collapse, supernova explosions or neutron stars. We construct the equation of state (EoS) of nuclear matter at finite temperature and density with various proton fractions within the relativistic density-dependent hadron-field theory (DDRH). The particular feature of this theory is a density-dependent description of in-medium NN interactions from an ab initio approach applying Dirac-Brueckner theory. The properties of nuclear matter with both uniform and non-uniform distributions are studied consistently. We also show results of calculations including hyperons and nuclear matter in ? equilibrium. Results for Fermi-Liquid parameters and quasi-elastic response functions are presented.

30

Boiling Patterns of Iso-asymmetric Nuclear Matter

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

Tõke, Jan

2013-03-01

31

International Nuclear Information System (INIS)

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

32

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

International Nuclear Information System (INIS)

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

33

Symmetric and asymmetric nuclear matter in the Thomas-Fermi model at finite temperatures

The properties of warm symmetric and asymmetric nuclear matter are investigated in the frame of the Thomas-Fermi approximation using a recent modern parametrization of the effective nucleon-nucleon interaction of Myers and Swiatecki. Special attention is paid to the liquid-gas phase transition, which is of special interest in modern nuclear physics. We have determined the critical temperature, critical density and the so-called flash temperature. Furthermore the equation of ...

Strobel, Klaus; Weber, Fridolin; Weigel, Manfred K.

1998-01-01

34

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

Within the Dirac-Brueckner-Hartree-Fock approach, using the Bonn potentials, we investigate the properties of dense, asymmetric nuclear matter and apply it to neutron stars. In the actual calculations of the nucleon self-energies and the energy density of matter, we study in detail the validity of an angle-averaged approximation and an averaging of the total momentum squared of interacting two-nucleons in nuclear matter. For practical use, we provide convenient parametrizations for the equation of state for symmetric nuclear matter and pure neutron matter. We also parametrize the nucleon self-energies in terms of polynomials of nucleon momenta. Those parametrizations can accurately reproduce the numerical results up to high densities.

Katayama, Tetsuya

2013-01-01

35

Asymmetric nuclear matter studied by time-dependent local isospin density approximation

The dynamic response of asymmetric nuclear matter is studied by means of a time-dependent local isospin density approximation (TDLIDA) approach. Calculations are based on a local density energy functional derived by an auxiliary field diffusion Monte Carlo (AFDMC) calculation of bulk nuclear matter. Three types of excited states emerge: collective states, a continuum of quasiparticle-quasihole excitations and unstable solutions. These states are analyzed and discussed for different values of the nuclear density ? and isospin asymmetry ?=(N-Z)/A. An analytical expression of the compressibility as a function of ? and ? is derived which shows explicitly an instability of the neutron matter around ??0.09 fm-3 when a small fraction of protons are added to the system.

Lipparini, Enrico; Pederiva, Francesco

2013-08-01

36

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

The dynamic response of asymmetric nuclear matter is studied by using a Time-Dependent Local Isospin Density (TDLIDA) approximation approach. Calculations are based on a local density energy functional derived by an Auxiliary Field Diffusion Monte Carlo (AFDMC) calculation of bulk nuclear matter. Three types of excited states emerge: collective states, a continuum of quasi-particle-quasi-hole excitations and unstable solutions. These states are analyzed and discussed for different values of the nuclear density $\\rho$ and isospin asymmetry $\\xi=(N-Z)/A$. An analytical expression of the compressibility as a function of $\\rho$ and $\\xi$ is derived which show explicitly an instability of the neutron matter around $\\rho\\simeq 0.09 fm^{-3}$ when a small fraction of protons is added to the system.

Lipparini, Enrico

2013-01-01

37

Coexistence of phases in asymmetric nuclear matter under strong magnetic fields

The equation of state of nuclear matter is strongly affected by the presence of a magnetic field. Here we study the equilibrium configuration of asymmetric nuclear matter for a wide range of densities, isospin composition, temperatures and magnetic fields. Special attention is paid to the low density and low temperature domain, where a thermodynamical instability exists. Neglecting fluctuations of the Coulomb force, a coexistence of phases is found under such conditions, even for extreme magnetic intensities. We describe the nuclear interaction by using the non--relativistic Skyrme potential model within a Hartree--Fock approach. We found that the coexistence of phases modifies the equilibrium configuration, masking most of the manifestations of the spin polarized matter. However, the compressibility and the magnetic susceptibility show clear signals of this fact. Thermal effects are significative for both quantities, mainly out of the coexistence region.

Aguirre, R

2014-01-01

38

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

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

39

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

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

2014-01-01

40

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

Gandolfi, S.; Lovato, A.; Carlson, J.; Schmidt, Kevin E.

2014-12-01

41

Studies of the equation of state of asymmetric nuclear matter with R3B at FAIR

Directory of Open Access Journals (Sweden)

Full Text Available The R3B experiment at FAIR will offer unique opportunities worldwide to study the properties of bulk asymmetric nuclear matter, e.g. the phase diagram, equation of state, symmetry energy, transport coefficients and in-medium cross sections. The experiment will take advantage of the intense radioactive beams produced by the SuperFRS with energies up to 2 AGeV. We will outline this physics programme and describe the detector sub-systems of R3B which will enable these measurements. Some detectors are already under construction while others are at the planning/R&D stage.

Lemmon R.

2012-07-01

42

Surface and curvature properties of asymmetric nuclear matter are studied beyond the proton drip. Using the semiclassical extended Thomas-Fermi method, the calculations are performed in the non-relativistic and relativistic meson field theories (Skyrme forces and non linear sigma-omega parametrizations). First we discuss the bulk equilibrium between the nuclear and drip phases. Next we analyze the asymmetric surface as a function of the bulk neutron excess. We examine local ...

Centelles, M.; Del Estal, M.; Vinas, X.

1997-01-01

43

D mesons and charmonium states in asymmetric nuclear matter at finite temperatures

International Nuclear Information System (INIS)

We investigate the in-medium masses of D and D-bar mesons in the isospin-asymmetric nuclear matter at finite temperatures arising due to the interactions with the nucleons, the scalar-isoscalar meson ?, and the scalar-isovector meson ? within a SU(4) model. However, since the chiral symmetry is explicitly broken for the SU(4) case due to the large charm quark mass, we use the SU(4) symmetry here only to obtain the interactions of the D and D-bar mesons with the light hadron sector but use the observed values of the heavy hadron masses and empirical values of the decay constants. The in-medium masses of J/? and the excited charmonium states [?(3686) and ?(3770)] are also calculated in the hot isospin-asymmetric nuclear matter in the present investigation. These mass modifications arise due to the interaction of the charmonium states with the gluon condensates of QCD, simulated by a scalar dilaton field introduced to incorporate the broken scale invariance of QCD within the effective chiral model. The change in the mass of J/? in the nuclear matter with the density is seen to be rather small, as has been shown in the literature by using various approaches, whereas the masses of the excited states of charmonium [?(3686) and ?(3770)] are seen to have considerable drop at high densities. The present study of the in-medium masses of D (D-bar) mesons as well as of the charmonium states will be of relevance for the observables from the compressed baryonic matter, likee compressed baryonic matter, like the production and collective flow of the D (D-bar) mesons, resulting from the asymmetric heavy-ion collision experiments planned at the future facility of the GSI Facility for Antiproton and Ion Research. The mass modifications of D and D-bar mesons as well as of the charmonium states in hot nuclear medium can modify the decay of the charmonium states (?',?c,J/?) to DD-bar pairs in the hot dense hadronic matter. The small attractive potentials observed for the D-bar mesons may lead to formation of the D-bar mesic nuclei.

44

Thermodynamic instabilities in dense asymmetric nuclear matter and in compact stars

We investigate the presence of thermodynamic instabilities in compressed asymmetric baryonic matter, reachable in high energy heavy ion collisions, and in the cold ?-stable compact stars. To this end we study the relativistic nuclear equation of state with the inclusion of ?-isobars and require the global conservation of baryon and electric charge numbers. Similarly to the low density nuclear liquid-gas phase transition, we show that a phase transition can occur in dense asymmetric nuclear matter and it is characterized by both mechanical instability (fluctuations on the baryon density) and by chemical-diffusive instability (fluctuations on the electric charge concentration). Such thermodynamic instabilities can imply a very different electric charge fraction Z/A in the coexisting phases during the phase transition and favoring an early formation of ?- particles with relevant phenomenological consequences in the physics of the protoneutron stars and compact stars. Finally, we discuss the possible co-existence of very compact and very massive compact stars in terms of two separate families: compact hadronic stars and very massive quark stars.

Lavagno, A.; Drago, A.; Pagliara, G.; Pigato, D.

2014-07-01

45

International Nuclear Information System (INIS)

A phenomenological momentum dependent interaction (MDI) is considered to describe the equation of state (EOS) for isospin asymmetric nuclear matter (ANM), where the density dependence of the nuclear symmetry is the basic input. In this interaction, the symmetry energy shows soft dependence of density. Within the nonrelativistic mean field approach we calculate the nuclear matter fourth-order symmetry energy Esym,4(?). Our result shows that the value of Esym,4(?) at normal nuclear matter density ?0( = 0.161 fm-3) is less than 1 MeV conforming the empirical parabolic approximation to the EOS of ANM at ?0. Then the higher-order effects of the isospin asymmetry on the saturation density ?sat(?), binding energy per nucleon Ksat(?) and isobaric incompressibility Ksat(?) of ANM is being studied, where ? = [?n - ?p]/? is the isospin asymmetry. We have found that the fourth-order isospin asymmetry ? cannot be neglected, while calculating these quantities. Hence the second-order Ksat,2 parameter basically characterizes the isospin dependence of the incompressibility of ANM at saturation density. (author)

46

Energy Technology Data Exchange (ETDEWEB)

Momentum and density dependence of the isospin part of nuclear mean field u{tau}(k,{rho}) which is still, in part, the open problem of the old Lane potential is analysed using density dependent finite range effective interactions. The behaviour of u{tau}(k=kf,{rho}) around the Fermi momentum kf is found to be related to the density dependence of nuclear symmetry energy J{tau}({rho}) and nucleon effective mass M*(k=kf,{rho})/M in symmetric nuclear matter. The momentum dependence of u{tau}(k,{rho}) is separated out in terms of a simple functional u{tau}ex(k,{rho}) which vanishes at k=kf and involves only the finite range parts of the exchange interactions between pairs of like and unlike nucleons. Depending on the choice of the parameters of these exchange interactions two conflicting trends of momentum dependence are noticed which lead to two opposite types of splitting of neutron and proton effective masses. The equation of state of asymmetric nuclear matter and the high density behaviour of nuclear symmetry energy J{tau}({rho}) are studied by constraining the additional parameters involved on the basis that pure neutron matter should not be predicted to be bound by any reasonable nuclear interaction. Emphasis is also given on the need of experimental data sensitive to the differences between neutron and proton transport properties in highly asymmetric dense nuclear matter and its analysis to constrain the high density behaviour of nuclear symmetry energy as well as to resolve the controversy on the two opposite types of splitting of neutron and proton effective masses.

Behera, B. [Department of Physics, Sambalpur University, Jyoti Vihar, Burla, Sambalpur, Orissa PIN-768019 (India); Routray, T.R. [Department of Physics, Sambalpur University, Jyoti Vihar, Burla, Sambalpur, Orissa PIN-768019 (India)]. E-mail: phy_su@rediffmail.com; Pradhan, A. [Department of Physics, Sambalpur University, Jyoti Vihar, Burla, Sambalpur, Orissa PIN-768019 (India); Patra, S.K. [Institute of Physics, Sachivalaya Marg, Bhubaneswar, Orissa PIN-751005 (India); Sahu, P.K. [Institute of Physics, Sachivalaya Marg, Bhubaneswar, Orissa PIN-751005 (India)

2005-05-16

47

International Nuclear Information System (INIS)

Momentum and density dependence of the isospin part of nuclear mean field u?(k,?) which is still, in part, the open problem of the old Lane potential is analysed using density dependent finite range effective interactions. The behaviour of u?(k=kf,?) around the Fermi momentum kf is found to be related to the density dependence of nuclear symmetry energy J?(?) and nucleon effective mass M*(k=kf,?)/M in symmetric nuclear matter. The momentum dependence of u?(k,?) is separated out in terms of a simple functional u?ex(k,?) which vanishes at k=kf and involves only the finite range parts of the exchange interactions between pairs of like and unlike nucleons. Depending on the choice of the parameters of these exchange interactions two conflicting trends of momentum dependence are noticed which lead to two opposite types of splitting of neutron and proton effective masses. The equation of state of asymmetric nuclear matter and the high density behaviour of nuclear symmetry energy J?(?) are studied by constraining the additional parameters involved on the basis that pure neutron matter should not be predicted to be bound by any reasonable nuclear interaction. Emphasis is also given on the need of experimental data sensitive to the differences between neutron and proton transport properties in highly asymmetric dense nuclear matter and its analysis to constrain the high density behaviour of nuclear symmetry energy as well as to resolve the controversy on the two opthe controversy on the two opposite types of splitting of neutron and proton effective masses

48

Saturation properties of asymmetric nuclear matter to be obtained from unstable nuclei

Energy Technology Data Exchange (ETDEWEB)

We examine relations among the parameters characterizing the phenomenological equation of state (EOS) of nearly symmetric, uniform nuclear matter near the saturation density from experimental data on radii and masses of stable nuclei. The EOS parameters of interest are the symmetry energy S{sub 0}, the symmetry energy density-derivative coefficient L and the incompressibility K{sub 0} at the normal nuclear density. The calculations of the nuclear properties were performed with a simplified Thomas-Fermi model. We find a constraint on (K{sub 0}, L) values from the slope of the saturation line (the line joining the saturation points of asymmetric matter EOS with fixed proton abundance). A strong correlation between S{sub 0} and L, which was discussed in the Skyrme Hartree-Fock theory for relatively small L values, is found to hold for such larger values as a relativistic mean field theory predicts. In the light of the uncertainties in the (K{sub 0}, L) values, we calculate radii of unstable nuclei as expected to be produced in future facilities. We find that the matter radii depend strongly on L almost independently of K{sub 0}, and that systematic detection of the radii of such nuclei will help to determine the L value. (author)

Oyamatsu, Kazuhiro [Aichi Shukutoku Univ., Dept. of Media Production and Theories, Nagakute, Aichi (Japan); Iida, Kei [Institute of Physical and Chemical Research, Wako, Saitama (Japan)

2002-09-01

49

The Equation of State (EOS) of isospin asymmetric nuclear matter plays a crucial role in many important issues in astrophysics, the structure of exotic nuclei and the reaction dynamics of heavy-ion collisions. Using in-medium hadronic properties according to the Brown-Rho scaling due to the chiral symmetry restoration at high densities and considering naturalness of the coupling constants, we have constructed several relativistic mean-field (RMF) Lagrangians with chiral limits. The scalings and associated parameters that describe the in-medium hadronic properties are consistent with those from microscopic calculations or those extracted from recent experimental data. The resulting equations of state are used to produce a heavier maximum neutron star mass around twice solar mass consistent with recent observations. A satisfactory description for ground-state properties of finite nuclei is also achieved with these RMF models. Meanwhile, the asymmetric matter densities produced by these models are applied to calculate the in-medium NN cross sections at high energies in the relativistic impulse approximation. Furthermore, due to the importance of the Fock terms, an extension to the relativistic Hartree-Fock framework is expected for the current RMF models.

Jiang, Wei-Zhou; Li, Bao-An; Chen, Lie-Wen

2007-10-01

50

We study the effect of a strong magnetic field on the proton and neutron spin polarization and magnetic susceptibility of asymmetric nuclear matter within a relativistic mean-field approach. It is shown that magnetic fields $B \\sim 10^{16} - 10^{17}$ G have already noticeable effects on the range of densities of interest for the study of the crust of a neutron star. Although the proton susceptibility is larger for weaker fields, the neutron susceptibility becomes of the same order or even larger for small proton fractions and subsaturation densities for $B > 10^{16}$ G. We expect that neutron superfluidity in the crust will be affected by the presence of magnetic fields.

Rabhi, A; Providência, C; Vidaña, I

2014-01-01

51

Energy Technology Data Exchange (ETDEWEB)

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

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

2014-02-15

52

International Nuclear Information System (INIS)

Surface and curvature properties of asymmetric semi-infinite nuclear matter are studied to beyond the proton drip. Using the semiclassical extended Thomas-Fermi method with corrections of order ?2, the calculations are performed in the non-relativistic and relativistic mean field theories (Skyrme forces and non-linear ?-? parametrizations). First we discuss the bulk equilibrium between the nuclear and drip phases. Next we analyse the asymmetric surface as a function of the bulk neutron excess. We examine local quantities related to the density profiles and, for two definitions of the bulk reference energy, the surface and curvature energy coefficients. The calculation of the curvature energy is carefully treated. The sensitivity of the nuclear surface to the relativistic effects is investigated. Mass formulae useful for arbitrary neutron excess are discussed, and their limit at small asymmetries is compared with the liquid droplet model mass formula. (orig.)

53

Annihilating Asymmetric Dark Matter

The relic abundance of particle and antiparticle dark matter (DM) need not be vastly different in thermal asymmetric dark matter (ADM) models. By considering the effect of a primordial asymmetry on the thermal Boltzmann evolution of coupled DM and anti-DM, we derive the requisite annihilation cross section. This is used in conjunction with CMB and Fermi-LAT gamma-ray data to impose a limit on the number density of anti-DM particles surviving thermal freeze-out. When the extended gamma-ray emission from the Galactic Center is reanalyzed in a thermal ADM framework, we find that annihilation into $\\tau$ leptons prefer anti-DM number densities 1-4$\\%$ that of DM while the $b$-quark channel prefers 50-100$\\%$.

Bell, Nicole F; Shoemaker, Ian M

2014-01-01

54

Annihilating asymmetric dark matter

The relic abundance of particle and antiparticle dark matter (DM) need not be vastly different in thermal asymmetric dark matter (ADM) models. By considering the effect of a primordial asymmetry on the thermal Boltzmann evolution of coupled DM and anti-DM, we derive the requisite annihilation cross section. This is used in conjunction with cosmic microwave background and Fermi-LAT gamma-ray data to impose a limit on the number density of anti-DM particles surviving thermal freeze-out. When the extended gamma-ray emission from the Galactic Center is reanalyzed in a thermal ADM framework, we find that annihilation into ? leptons prefer anti-DM number densities 1%-4% that of DM while the b -quark channel prefers 50%-100%.

Bell, Nicole F.; Horiuchi, Shunsaku; Shoemaker, Ian M.

2015-01-01

55

We study the asymmetric nuclear matter using a holographic QCD model by introducing a baryonic charge in the infrared boundary. We first show that, in the normal hadron phase, the predicted values of the symmetry energy and its slope parameter are comparable with the empirical values. We find that the phase transition from the normal phase to the pion condensation phase is delayed compared with the pure mesonic matter: the critical chemical potential is larger than the pion mass which is obtained for the pure mesonic matter. We also show that, in the pion condensation phase, the pion contribution to the isospin number density increases with the chemical potential, while the baryonic contribution is almost constant. Furthermore, the value of chiral condensation implies that the enhancement of the chiral symmetry breaking occurs in the asymmetric nuclear matter as in the pure mesonic matter. We also give a discussion on how to understand the delay in terms of the four-dimensional chiral Lagrangian including the rho and omega mesons based on the hidden local symmetry.

Nishihara, Hiroki; Harada, Masayasu

2014-12-01

56

We study the asymmetric nuclear matter using a holographic QCD model by introducing a baryonic charge in the infrared boundary. We first show that, in the normal hadron phase, the predicted values of the symmetry energy and it's slope parameter are comparable with the empirical values. We find that the phase transition from the normal phase to the pion condensation phase is delayed compared with the pure mesonic matter: The critical chemical potential is larger than the pion mass which is obtained for the pure mesonic matter. We also show that, in the pion condensation phase, the pion contribution to the isospin number density increases with the chemical potential, while the baryonic contribution is almost constant. Furthermore, the value of chiral condensation implies that the enhancement of the chiral symmetry breaking occurs in the asymmetric nuclear matter as in the pure mesonic matter. We also give a discussion on how to understand the delay in terms of the 4-dimensional chiral Lagrangian including the r...

Nishihara, Hiroki

2014-01-01

57

Review of asymmetric dark matter

Asymmetric dark matter models are based on the hypothesis that the present-day abundance of dark matter has the same origin as the abundance of ordinary or visible matter: an asymmetry in the number densities of particles and antiparticles. They are largely motivated by the observed similarity in the mass densities of dark and visible matter, with the former observed to be about five times the latter. This review discusses the construction of asymmetric dark matter models, summarizes cosmological and astrophysical implications and bounds, and touches on direct detection prospects and collider signatures.

Petraki, Kalliopi

2013-01-01

58

Nuclear matter and nuclear dynamics

International Nuclear Information System (INIS)

Highlights on the recent research activity, carried out by the Italian Community involved in the 'Nuclear matter and nuclear dynamics' field, will be presented. In particular, we discuss new results on the Equation of State (EOS) of asymmetric nuclear matter, from microscopic many-body approaches on one side and from the study of sensitive observables in dissipative nuclear reactions on the other. Considering a wide range of beam energies, it is possible to explore the behavior of the EOS symmetry term in several conditions of density and temperature. New results concerning the structure and the life of neutron stars, that are affected by the high density behavior of asymmetric nuclear matter, will also be reported.

59

Nuclear matter and nuclear dynamics

Energy Technology Data Exchange (ETDEWEB)

Highlights on the recent research activity, carried out by the Italian Community involved in the 'Nuclear matter and nuclear dynamics' field, will be presented. In particular, we discuss new results on the Equation of State (EOS) of asymmetric nuclear matter, from microscopic many-body approaches on one side and from the study of sensitive observables in dissipative nuclear reactions on the other. Considering a wide range of beam energies, it is possible to explore the behavior of the EOS symmetry term in several conditions of density and temperature. New results concerning the structure and the life of neutron stars, that are affected by the high density behavior of asymmetric nuclear matter, will also be reported.

Colonna, M, E-mail: colonna@lns.infn.i [Laboratori Nazionali del Sud, INFN, via Santa Sofia 62, I-95123, Catania (Italy)

2009-05-01

60

Active matter on asymmetric substrates

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

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

2011-10-01

61

Energy Technology Data Exchange (ETDEWEB)

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

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

2014-02-15

62

International Nuclear Information System (INIS)

By using the most recent generalized form of the density-dependent nucleon-nucleon DDM3Y interaction, namely, CDM3Yn-Paris interaction, the basic static properties of symmetric and asymmetric nuclear matter such as binding energy per particle, pressure, velocity of sound, and compressibility are calculated. Also, at finite temperature, the thermal properties of nuclear matter are studied, such as the free energy, the pressure, the entropy, and the compressibility. In addition, a comparison using different density-dependent M3Y-Paris interaction (DDM3Y1 and BDM3Y1) is considered. The importance of using the density-dependent term in the M3Y-Paris interaction is to fulfill the saturation requirement for the nuclear matter because M3Y-Paris interaction has an attractive character. Thus, the nuclear matter generated with this interaction is unstable against collapse. This new version of the DDM3Y is the general one, and other previous density-dependent forms can be considered as a special case of this one. Therefore, all the explicit theoretical developments are based on the density-dependent CDM3Yn version. The results obtained are in good agreement with previous theoretical estimates

63

It is known that the decay process \\eta\\rightarrow\\pi^0\\pi^+\\pi^- in free space is possible due to the isospin-symmetry breaking in Quantum Chromodynamics (QCD), i.e., the small mass difference between u and d quarks: The small width is intimately related with the mixing property between \\eta and \\pi^0 mesons for which the chiral anomaly play a role. In asymmetric nuclear matter such as heavy nuclei, isospin-symmetry breaking is large and it is expected that the mixing property of the mesons changes significantly and the above-mentioned decay width of the \\eta created in such a medium may be enhanced. This is an intriguing possibility to revealing a medium effect on a hadron in nuclei. We apply the in-medium chiral perturbation theory to estimate the modification of the \\eta -\\pi^0 mixing angle and the partial width of \\eta\\pi^0\\pi^+\\pi^- in asymmetric nuclear matter as a function of the isospin asymmetry. We find that these quantities can be greatly enhanced in neutron-rich matter, which should be deteactabl...

Sakai, Shutaro

2014-01-01

64

Asymmetric Dark Matter and Effective Operators

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 tha...

Buckley, Matthew R.

2011-01-01

65

The formalism of linear response theory for a Skyrme functional including spin-orbit and tensor terms is generalized to the case of infinite nuclear matter with arbitrary isospin asymmetry. Response functions are obtained by solving an algebraic system of equations, which is explicitly given. Spin-isospin strength functions are analyzed varying the conditions of density, momentum transfer, asymmetry and temperature. The presence of instabilities, including the spinodal one, is studied by means of the static susceptibility.

Davesne, D; Navarro, J

2014-01-01

66

We report on $J/\\psi$ production from asymmetric Cu+Au heavy-ion collisions at $\\sqrt{s_{_{NN}}}$=200 GeV at the Relativistic Heavy Ion Collider at both forward (Cu-going direction) and backward (Au-going direction) rapidities. The nuclear modification of $J/\\psi$ yields in Cu$+$Au collisions in the Au-going direction is found to be comparable to that in Au$+$Au collisions when plotted as a function of the number of participating nucleons. In the Cu-going direction, $J/\\psi$ production shows a stronger suppression. This difference is comparable in magnitude and has the same sign as the difference expected from shadowing effects due to stronger low-$x$ gluon suppression in the larger Au nucleus. The relative suppression is opposite to that expected from hot nuclear matter dissociation, since a higher energy density is expected in the Au-going direction.

Aidala, C; Akiba, Y; Akimoto, R; Alexander, J; Aoki, K; Apadula, N; Asano, H; Atomssa, E T; Awes, T C; Azmoun, B; Babintsev, V; Bai, M; Bai, X; Bannier, B; Barish, K N; Bathe, S; Baublis, V; Baumann, C; Baumgart, S; Bazilevsky, A; Beaumier, M; Belmont, R; Berdnikov, A; Berdnikov, Y; Bing, X; Black, D; Blau, D S; Bok, J; Boyle, K; Brooks, M L; Bryslawskyj, J; Buesching, H; Bumazhnov, V; Butsyk, S; Campbell, S; Chen, C -H; Chi, C Y; Chiu, M; Choi, I J; Choi, J B; Choi, S; Christiansen, P; Chujo, T; Cianciolo, V; Cole, B A; Cronin, N; Crossette, N; Csanád, M; Csörg?, T; Datta, A; Daugherity, M S; David, G; Dehmelt, K; Denisov, A; Deshpande, A; Desmond, E J; Ding, L; Do, J H; Drapier, O; Drees, A; Drees, K A; Durham, J M; Durum, A; D'Orazio, L; Engelmore, T; Enokizono, A; Esumi, S; Eyser, K O; Fadem, B; Fields, D E; Finger, M; Finger,, M; Fleuret, F; Fokin, S L; Frantz, J E; Franz, A; Frawley, A D; Fukao, Y; Gainey, K; Gal, C; Garg, P; Garishvili, A; Garishvili, I; Giordano, F; Glenn, A; Gong, X; Gonin, M; Goto, Y; de Cassagnac, R Granier; Grau, N; Greene, S V; Perdekamp, M Grosse; Gu, Y; Gunji, T; Guragain, H; Haggerty, J S; Hahn, K I; Hamagaki, H; Hanks, J; Hashimoto, K; Hayano, R; He, X; Hemmick, T K; Hester, T; Hill, J C; Hollis, R S; Homma, K; Hong, B; Hoshino, T; Huang, J; Huang, S; Ichihara, T; Ikeda, Y; Imai, K; Imazu, Y; Inaba, M; Iordanova, A; Isenhower, D; Isinhue, A; Ivanishchev, D; Jacak, B V; Jeon, S J; Jezghani, M; Jia, J; Jiang, X; Johnson, B M; Joo, K S; Jouan, D; Jumper, D S; Kamin, J; Kanda, S; Kang, B H; Kang, J H; Kang, J S; Kapustinsky, J; Kawall, D; Kazantsev, A V; Key, J A; Khachatryan, V; Khandai, P K; Khanzadeev, A; Kijima, K M; Kim, C; Kim, D J; Kim, E -J; Kim, Y -J; Kim, Y K; Kistenev, E; Klatsky, J; Kleinjan, D; Kline, P; Koblesky, T; Kofarago, M; Komkov, B; Koster, J; Kotchetkov, D; Kotov, D; Krizek, F; Kurita, K; Kurosawa, M; Kwon, Y; Lacey, R; Lai, Y S; Lajoie, J G; Lebedev, A; Lee, D M; Lee, G H; Lee, J; Lee, K B; Lee, K S; Lee, S H; Leitch, M J; Leitgab, M; Lewis, B; Li, X; Lim, S H; Liu, M X; Lynch, D; Maguire, C F; Makdisi, Y I; Makek, M; Manion, A; Manko, V I; Mannel, E; Maruyama, T; McCumber, M; McGaughey, P L; McGlinchey, D; McKinney, C; Meles, A; Mendoza, M; Meredith, B; Miake, Y; Mibe, T; Mignerey, A C; Milov, A; Mishra, D K; Mitchell, J T; Miyasaka, S; Mizuno, S; Mohanty, A K; Morrison, D P; Moskowitz, M; Moukhanova, T V; Murakami, T; Murata, J; Nagae, T; Nagamiya, S; Nagle, J L; Nagy, M I; Nakagawa, I; Nakamiya, Y; Nakamura, K R; Nakamura, T; Nakano, K; Nattrass, C; Netrakanti, P K; Nihashi, M; Niida, T; Nouicer, R; Novak, T; Novitzky, N; Nyanin, A S; O'Brien, E; Ogilvie, C A; Oide, H; Okada, K; Oskarsson, A; Ozawa, K; Pak, R; Pantuev, V; Papavassiliou, V; Park, I H; Park, S; Park, S K; Pate, S F; Patel, L; Peng, J -C; Perepelitsa, D; Perera, G D N; Peressounko, D Yu; Perry, J; Petti, R; Pinkenburg, C; Pisani, R P; Purschke, M L; Qu, H; Rak, J; Ravinovich, I; Read, K F; Reynolds, D; Riabov, V; Riabov, Y; Richardson, E; Riveli, N; Roach, D; Rolnick, S D; Rosati, M; Ryu, M S; Sahlmueller, B; Saito, N; Sakaguchi, T; Sako, H; Samsonov, V; Sarsour, M; Sato, S; Sawada, S; Sedgwick, K; Seele, J; Seidl, R; Sekiguchi, Y; Sen, A; Seto, R; Sett, P; Sharma, D; Shaver, A; Shein, I; Shibata, T -A; Shigaki, K; Shimomura, M; Shoji, K; Shukla, P; Sickles, A; Silva, C L; Silvermyr, D; Singh, B K; Singh, C P; Singh, V; Skolnik, M; Slune?ka, M; Solano, S; Soltz, R A; Sondheim, W E; Sorensen, S P; Soumya, M; Sourikova, I V; Stankus, P W; Steinberg, P; Stenlund, E; Stepanov, M; Ster, A; Stoll, S P; Stone, M R; Sugitate, T; Sukhanov, A; Sun, J; Takahara, A; Taketani, A; Tanida, K; Tannenbaum, M J; Tarafdar, S; Taranenko, A; Tennant, E; Timilsina, A; Todoroki, T; Tomášek, M; Torii, H; Towell, R S; Tserruya, I; van Hecke, H W; Vargyas, M; Vazquez-Zambrano, E; Veicht, A; Velkovska, J; Vértesi, R; Virius, M; Vrba, V; Vznuzdaev, E; Wang, X R; Watanabe, D; Watanabe, K; Watanabe, Y; Watanabe, Y S; Wei, F; Whitaker, S; Wolin, S; Woody, C L; Wysocki, M; Yamaguchi, Y L; Yanovich, A; Yokkaichi, S; Yoon, I; You, Z; Younus, I; Yushmanov, I E; Zajc, W A; Zelenski, A; Zhou, S

2014-01-01

67

Baryon Destruction by Asymmetric Dark Matter

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

Davoudiasl, Hooman; Sigurdson, Kris; Tulin, Sean

2011-01-01

68

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.

69

Phenomenology of light fermionic asymmetric dark matter

Asymmetric dark matter (ADM) has been an attractive possibility attempting to explain the observed ratio of baryon to dark matter abundance in the universe. While a bosonic ADM is 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

70

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 neutri 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.

71

Constraints on asymmetric dark matter from asteroseismology

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

72

Excluding Light Asymmetric Bosonic Dark Matter

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 cons...

Kouvaris, Chris; Tinyakov, Peter

2011-01-01

73

An effective Nuclear Model: from Nuclear Matter to Finite Nuclei

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 ...

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

2012-01-01

74

Asymmetric Dark Matter and Dark Radiation

International Nuclear Information System (INIS)

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

75

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

76

Charge asymmetric cosmic rays as a probe of flavor violating asymmetric dark matter

International Nuclear Information System (INIS)

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

77

Fixed-Velocity Chiral Sum Rules for Nuclear Matter

Infinite sets of sum rules involving the excitations of infinite nuclear matter are derived using only completeness, the current algebra implicit in QCD, and relativistic covariance. The sum rules can be used for isospin-asymmetric nuclear matter, including neutron matter. They relate the chiral condensate and the isospin density to weighted sums over states with fixed velocity relative to the nuclear matter ground state.

Cohen, T D; Cohen, Thomas D.; Broniowski, Wojciech

1997-01-01

78

Superluminosity in nuclear matter

International Nuclear Information System (INIS)

In this work the main objective is to construct the effective interaction which ensures that causal violation of speed of sound does not occur at high density along with the other nuclear matter properties

79

International Nuclear Information System (INIS)

Nuclear matter exists in different forms under different conditions of temperature and pressure, just as in the case of water. The phase diagram of nuclear matter spans a vast region of temperature and density, starting with the quark-gluon phase of the early universe at high temperature to the high-density matter that exists in the core of the neutron star. Between the two extremes, at least two spectacular phase transitions occur: the quark-hadron transition and the nuclear liquid-gas phase transition. There have been predictions for two critical points corresponding to the two phase transitions. We present the phase diagram of nuclear matter, give an overview of both types of phase transitions and discuss the critical points of the phase diagram. (author)

80

An effective Nuclear Model: from Nuclear Matter to Finite Nuclei

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.; Vinas, X.; Tripathy, S. K.; Bhuyan, M.; Patra, S. K.; Behera, B.

2013-03-01

81

An effective Nuclear Model: from Nuclear Matter to Finite Nuclei

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

82

Isospin violating dark matter being asymmetric

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 interf...

Okada, Nobuchika; Seto, Osamu

2013-01-01

83

Upper bounds on asymmetric dark matter self annihilation cross sections

International Nuclear Information System (INIS)

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

84

Upper Bounds on Asymmetric Dark Matter Self Annihilation Cross Sections

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

85

We study the behavior of cold nuclear matter near saturation density (\\rho 0) and very low temperature using classical molecular dynamics. We used three different (classical) nuclear interaction models that yield `medium' or `stiff' compressibilities. For high densities and for every model the ground state is a classical crystalline solid, but each one with a different structure. At subsaturation densities, we found that for every model the transition from uniform (crystal) to non-uniform matter occurs at \\rho ~ 0.12 fm^(-3) = 0.75 \\rho 0. Surprisingly, at the non-uniform phase, the three models produce `pasta-like' structures as those allegedly present in neutron star matter but without the long-range Coulomb interaction and with different length scales.

Dorso, C O; Nichols, J I; López, J A

2012-01-01

86

Continuous flavor symmetries and the stability of asymmetric dark matter

Generically, the asymmetric interactions in asymmetric dark matter (ADM) models could lead to decaying DM. We show that, for ADM that carries nonzero baryon number, the continuous flavor symmetries that generate the flavor structure in the quark sector also imply a looser lower bound on the mass scale of the asymmetric mediators between the dark and visible sectors. The mediators for B = 2 ADM that can produce a signal in the future indirect dark matter searches can thus also be searched for at the LHC. For two examples of the mediator models, with either the MFV or Froggatt-Nielsen flavor breaking pattern, we derive the FCNC constraints and discuss the search strategies at the LHC.

Bishara, Fady; Zupan, Jure

2015-01-01

87

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 and some residual interaction constrained by Adler's consistency condition. The kaon spectra in nuclear matter are discussed as well as the possibility of K- and anti K0 condensation in dense nuclear matter. (orig.)

88

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

89

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

90

Gamma ray constraints on flavor violating asymmetric dark matter

International Nuclear Information System (INIS)

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 HESS 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 ?-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

91

Nucleon properties in nuclear matter

We present recent studies on the effective mass of the nucleon in infinite and homogeneous nuclear matter and its relation to nuclear matter properties within the framework of the in-medium modified Skyrme model. Medium modifications are achieved by introducing optical potential for pion fields and parametrization of the Skyrme parameter in nuclear medium. The present approach is phenomenologically well justified by pion physics in nuclear matter and describe successfully bu...

Yakhshiev, Ulugbek; Kim, Hyun-chul

2011-01-01

92

Decaying asymmetric dark matter relaxes the AMS-Fermi tension

International Nuclear Information System (INIS)

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, X-bar ) with a tiny coupling LHuX, which makes the ADM share the lepton asymmetry and decay into ???+ along the operator LLEc

93

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

94

International Nuclear Information System (INIS)

The subject of the doctoral thesis is examination of the properties of kaons in nuclear matter. A specific method is explained that has been developed for the scientific objectives of the thesis and permits description of the kaon-nucleon interactions and kaon-nucleon scattering in a vacuum. The main challenge involved was to find approaches that would enable application of the derived relations out of the kaon mass shell, connected with the second objective, namely to possibly find methods which are independent of models. The way chosen to achieve this goal relied on application of reduction formulas as well as current algebra relations and the PCAC hypothesis. (orig./CB)

95

Spectral properties of nuclear matter

We review self-consistent spectral methods for nuclear matter calculations. The in-medium T-matrix approach is conserving and thermodynamically consistent. It gives both the global and the single-particle properties the system. The T-matrix approximation allows to address the pairing phenomenon in cold nuclear matter. A generalization of nuclear matter calculations to the superfluid phase is discussed and numerical results are presented for this case. The linear response of ...

Bozek, P.

2005-01-01

96

Nuclear Matter Equation of State and Three body Forces

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

Mansour, Hesham M. M.; Gamoudi, Abdelsalam

2011-01-01

97

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

98

Possible implications of asymmetric fermionic dark matter for neutron stars

International Nuclear Information System (INIS)

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

99

Covariant density functional theory for nuclear matter

Energy Technology Data Exchange (ETDEWEB)

The present thesis is organized as follows. In Chapter 2 we study the Nucleon-Nucleon (NN) interaction in Dirac-Brueckner (DB) approach. We start by considering the NN interaction in free-space in terms of the Bethe-Salpeter (BS) equation to the meson exchange potential model. Then we present the DB approach for nuclear matter by extending the BS equation for the in-medium NN interaction. From the solution of the three-dimensional in-medium BS equation, we derive the DB self-energies and total binding energy which are the main results of the DB approach, which we later incorporate in the field theoretical calculation of the nuclear equation of state. In Chapter 3, we introduce the basic concepts of density functional theory in the context of Quantum Hadrodynamics (QHD-I). We reach the main point of this work in Chapter 4 where we introduce the DDRH approach. In the DDRH theory, the medium dependence of the meson-nucleon vertices is expressed as functionals of the baryon field operators. Because of the complexities of the operator-valued functionals we decide to use the mean-field approximation. In Chapter 5, we contrast microscopic and phenomenological approaches to extracting density dependent meson-baryon vertices. Chapter 6 gives the results of our studies of the EOS of infinite nuclear matter in detail. Using formulas derived in Chapters 4 and 5 we calculate the properties of symmetric and asymmetric nuclear matter and pure neutron matter. (orig.)

Badarch, U.

2007-07-01

100

Covariant density functional theory for nuclear matter

International Nuclear Information System (INIS)

The present thesis is organized as follows. In Chapter 2 we study the Nucleon-Nucleon (NN) interaction in Dirac-Brueckner (DB) approach. We start by considering the NN interaction in free-space in terms of the Bethe-Salpeter (BS) equation to the meson exchange potential model. Then we present the DB approach for nuclear matter by extending the BS equation for the in-medium NN interaction. From the solution of the three-dimensional in-medium BS equation, we derive the DB self-energies and total binding energy which are the main results of the DB approach, which we later incorporate in the field theoretical calculation of the nuclear equation of state. In Chapter 3, we introduce the basic concepts of density functional theory in the context of Quantum Hadrodynamics (QHD-I). We reach the main point of this work in Chapter 4 where we introduce the DDRH approach. In the DDRH theory, the medium dependence of the meson-nucleon vertices is expressed as functionals of the baryon field operators. Because of the complexities of the operator-valued functionals we decide to use the mean-field approximation. In Chapter 5, we contrast microscopic and phenomenological approaches to extracting density dependent meson-baryon vertices. Chapter 6 gives the results of our studies of the EOS of infinite nuclear matter in detail. Using formulas derived in Chapters 4 and 5 we calculate the properties of symmetric and asymmetric nuclear matter and pure neutron matter. (orig.)

101

Nuclear matter and electron scattering

Energy Technology Data Exchange (ETDEWEB)

We show that inclusive electron scattering at large momentum transfer allows a measurement of short-range properties of nuclear matter. This provides a very valuable constraint in selecting the calculations appropriate for predicting nuclear matter properties at the densities of astrophysical interest. (orig.)

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

1998-06-01

102

Nuclear matter and electron scattering

International Nuclear Information System (INIS)

We show that inclusive electron scattering at large momentum transfer allows a measurement of short-range properties of nuclear matter. This provides a very valuable constraint in selecting the calculations appropriate for predicting nuclear matter properties at the densities of astrophysical interest. (orig.)

103

Magnetic catalysis in nuclear matter

Due to magnetic catalysis, a strong magnetic field enhances the chiral condensate at low temperatures and thus can also be expected to increase the vacuum mass of nucleons. We employ two relativistic field-theoretical models for nuclear matter, the Walecka model and an extended linear sigma model, to discuss the resulting effect on the transition between vacuum and nuclear matter at zero temperature. In both models we find that the creation of nuclear matter in a sufficiently strong magnetic field becomes energetically more costly due to the heaviness of magnetized nucleons, even though it is also found that nuclear matter is more strongly bound in a magnetic field. Our results are potentially important for dense nuclear matter in compact stars, especially since previous studies in the astrophysical context have always ignored the contribution of the magnetized Dirac sea and thus the effect of magnetic catalysis.

Haber, Alexander; Schmitt, Andreas

2014-01-01

104

Asymmetric dark matter via spontaneous co-genesis

Energy Technology Data Exchange (ETDEWEB)

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, ?{sub DM}?/?{sub B} ? 5. The co-genesis mechanism requires a light scalar field, ?, with mass below 5 eV which couples derivatively to DM, much like a 'dark axion'. The field ? can itself provide a final state into which the residual symmetric DM component can annihilate away.

March-Russell, John; McCullough, Matthew, E-mail: jmr@thphys.ox.ac.uk, E-mail: mccull@thphys.ox.ac.uk [Rudolf Peierls Centre for Theoretical Physics, University of Oxford, 1 Keble Road, Oxford, OX1 3NP (United Kingdom)

2012-03-01

105

Asymmetric Dark Matter via Spontaneous Co-Genesis

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

106

Condensed Matter Nuclear Science

1. General. A tribute to gene Mallove - the "Genie" reactor / K. Wallace and R. Stringham. An update of LENR for ICCF-11 (short course, 10/31/04) / E. Storms. New physical effects in metal deuterides / P. L. Hagelstein ... [et al.]. Reproducibility, controllability, and optimization of LENR experiments / D. J. Nagel -- 2. Experiments. Electrochemistry. Evidence of electromagnetic radiation from Ni-H systems / S. Focardi ... [et al.]. Superwave reality / I. Dardik. Excess heat in electrolysis experiments at energetics technologies / I. Dardik ... [et al.]. "Excess heat" during electrolysis in platinum/K[symbol]CO[symbol]/nickel light water system / J. Tian ... [et al.]. Innovative procedure for the, in situ, measurement of the resistive thermal coefficient of H(D)/Pd during electrolysis; cross-comparison of new elements detected in the Th-Hg-Pd-D(H) electrolytic cells / F. Celani ... [et al.]. Emergence of a high-temperature superconductivity in hydrogen cycled Pd compounds as an evidence for superstoihiometric H/D sites / A. Lipson ... [et al.]. Plasma electrolysis. Calorimetry of energy-efficient glow discharge - apparatus design and calibration / T. B. Benson and T. O. Passell. Generation of heat and products during plasma electrolysis / T. Mizuno ... [et al.]. Glow discharge. Excess heat production in Pd/D during periodic pulse discharge current in various conditions / A. B. Karabut. Beam experiments. Accelerator experiments and theoretical models for the electron screening effect in metallic environments / A. Huke, K. Czerski, and P. Heide. Evidence for a target-material dependence of the neutron-proton branching ratio in d+d reactions for deuteron energies below 20keV / A. Huke ... [et al.]. Experiments on condensed matter nuclear events in Kobe University / T. Minari ... [et al.]. Electron screening constraints for the cold fusion / K. Czerski, P. Heide, and A. Huke. Cavitation. Low mass 1.6 MHz sonofusion reactor / R. Stringham. Particle detection. Research into characteristics of X-ray emission laser beams from solidstate cathode medium of high-current glow discharge / A. B. Karabut. Charged particles from Ti and Pd foils / L. Kowalski ... [et al.]. Cr-39 track detectors in cold fusion experiments: review and perspectives / A. S. Roussetski. Energetic particle shower in the vapor from electrolysis / R. A. Oriani and J. C. Fisher. Nuclear reactions produced in an operating electrolysis cell / R. A. Oriani and J. C. Fisher. Evidence of microscopic ball lightning in cold fusion experiments / E. H. Lewis. Neutron emission from D[symbol] gas in magnetic fields under low temperature / T. Mizuno ... [et al.]. Energetic charged particle emission from hydrogen-loaded Pd and Ti cathodes and its enhancement by He-4 implantation / A. G. Lipson ... [et al.]. H-D permeation. Observation of nuclear transmutation reactions induced by D[symbol] gas permeation through Pd complexes / Y. Iwamura ... [et al.]. Deuterium (hydrogen) flux permeating through palladium and condensed matter nuclear science / Q. M. Wei ... [et al.]. Triggering. Precursors and the fusion reactions in polarized Pd/D-D[symbol]O system: effect of an external electric field / S. Szpak, P. A. Mosier-Boss, and F. E. Gordon. Calorimetric and neutron diagnostics of liquids during laser irradiation / Yu. N. Bazhutov ... [et al.]. Anomalous neutron capture and plastic deformation of Cu and Pd cathodes during electrolysis in a weak thermalized neutron field: evidence of nuclei-lattice exchange / A. G. Lipson and G. H. Miley. H-D loading. An overview of experimental studies on H/Pd over-loading with thin Pd wires and different electrolytic solutions / A. Spallone ... [et al.] -- 3. Transmutations. Photon and particle emission, heat production, and surface transformation in Ni-H system / E. Campari ... [et al.]. Surface analysis of hydrogen-loaded nickel alloys / E. Campari ... [et al.]. Low-energy nuclear reactions and the leptonic monopole / G. Lochak and L. Urutskoev. Results of analysis of Ti foil after glow discharge with deuterium / I. B. Savvat

Biberian, Jean-Paul

2006-02-01

107

Chiral thermodynamics of nuclear matter

International Nuclear Information System (INIS)

The equation of state of nuclear matter is calculated at finite temperature in the framework of in-medium chiral perturbation theory up to three-loop order. The dependence of its thermodynamic properties on the isospin-asymmetry is investigated. The chiral quark condensate is evaluated for symmetric nuclear matter. Its behaviour as a function of density and temperature sets important nuclear physics constraints for the QCD phase diagram.

108

Thermostatic properties of semi-infinite nuclear matter

International Nuclear Information System (INIS)

Low-temperature (T) properties of hot, asymmetric nuclear matter have been studied with the hot, modified Thomas-Fermi (HMTF) method. The evolution with T of volume, volume symmetry, surface and surface symmetry energies corresponding to several Skyrme forces is presented. (author)

109

Charmonium mass in nuclear matter

The mass shift of charmonium states in nuclear matter is studied in the perturbative QCD approach. The leading-order effect due to the change of gluon condensate in nuclear matter is evaluated using the leading-order QCD formula, while the higher-twist effect due to the partial restoration of chiral symmetry is estimated using a hadronic model. We find that while the mass of $J/\\psi$ in nuclear matter decreases only slightly, those of $\\psi(3686)$ and $\\psi(3770)$ states are...

Ko, C. M.; Lee, Su Houng

2002-01-01

110

Phase transitions in nuclear matter

International Nuclear Information System (INIS)

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

111

Bottomonium states in hot asymmetric strange hadronic matter

We calculate the in-medium masses of the bottomonium states [?(1S),?(2S),?(3S), and ? (4S)] in isospin asymmetric strange hadronic matter at finite temperatures. The medium modifications of the masses arise due to the interaction of these heavy quarkonium states with the gluon condensates of QCD. The gluon condensates in the hot hadronic matter are computed from the medium modification of a scalar dilaton field within a chiral SU(3) model, introduced in the hadronic model to incorporate the broken scale invariance of QCD. There is seen to be a drop in the masses of the bottomonium states and mass shifts are observed to be quite considerable at high densities for the excited states. The effects of density, isospin asymmetry, strangeness, as well as temperature of the medium on the masses of the ? states are investigated. The effects of the isospin asymmetry as well as strangeness fraction of the medium are seen to be appreciable at high densities and small temperatures. The density effects are the most dominant medium effects which should have observable consequences in the compressed baryonic matter (CBM) in the heavy ion collision experiments in the future facility at FAIR, GSI. The study of the ? states will, however, require access to energies higher than the energy regime planned at CBM experiment. The density effects on the bottomonium masses should also show up in the dilepton spectra at the Super Proton Synchrotron (SPS) energies, especially for the excited states for which the mass drop is observed to quite appreciable.

Mishra, Amruta; Pathak, Divakar

2014-08-01

112

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

113

Chiral thermodynamics of nuclear matter

International Nuclear Information System (INIS)

We present a calculation of the equation of state of nuclear matter in the frame of in-medium chiral perturbation theory. The calculations are performed up to three-loop order in the free energy density. The contributions to the free energy per particle originate from one- and two-pion exchange diagrams; the effects from two-pion exchange with ?-isobar excitation are also included, as well as three-body forces. The equation of state and the corresponding phase diagram, displaying the liquid-gas phase transition, is investigated for different proton-to-neutron ratios, from isospin-symmetric nuclear matter to the limiting case of pure neutron matter.

114

Anatomy of nuclear matter fundamentals

The bridge between finite and infinite nuclear system is analyzed for the fundamental quantities like binding energy, density, compressibility, giant monopole excitation energy and effective mass of both nuclear matter and finite nuclei systems. It is shown quantitatively that by knowing one of the fundamental property of one system one can estimate the same in its counter part, only approximately

Patra, S K; Singh, S K; Bhuyan, M

2014-01-01

115

Energy Technology Data Exchange (ETDEWEB)

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.

Chapman, S.

1992-11-01

116

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

117

Induced interaction stabilizing nuclear matter

International Nuclear Information System (INIS)

Excitation modes of nuclear matter at various densities are investigated including the effects of ? excitations. Collective features are observed at small densities in the scalar-isoscalar channel and at large densities for the longitudinal isovector mode. Using the Brueckner G-matrix for the residual interaction, the RPA approximation predicts an instability of nuclear matter against these modes. The renormalization of the residual interaction by the so called induced interaction yields a stabilization of the collective modes. The effects of the corresponding phonon exchange terms on the particle-hole interaction and on the effective mass are discussed. 8 refs.; 4 figs

118

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,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- similar (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 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 a new type inhomogeneous K- condensation. The K- condensate energy is calculated in the approximation of a small KK coupling constant. Accordingly, neutron star matter may undergo a first-order phase transition to proton matter with K- croton matter with K- condensate at ?>?c- due to p-wave interaction. The temperature dependence of the most important terms of the K- polarization operator is discussed. In a rather wide temperature region 0? a growing temperature enlarges the K-N attraction and promotes the kaon condensation. The possibility of p-wave K0 condensation is also considered. The question is qualitatively discussed whether proton matter with K- condensate or neutron matter with K0 condensate is energetically more favorable. ((orig.))

119

International Nuclear Information System (INIS)

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.)

120

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

121

Electron scattering from nuclear matter

International Nuclear Information System (INIS)

We use inclusive electron scattering to study the short-range aspects of nuclear matter wave functions. Comparison to data at large momentum transfer allows detailed studies of P(k, E) at large momenta, N-N correlations and colour transparency. (orig.)

122

On the nuclear stopping in asymmetric colliding nuclei

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

Kaur, Varinderjit; Kumar, Suneel; Puri, Rajeev K.

2010-01-01

123

On the nuclear stopping in asymmetric colliding nuclei

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

Kaur, Varinderjit; Puri, Rajeev K

2010-01-01

124

Isospin dependence of nuclear matter symmetry energy coefficients

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

Braghin, Fabio L.

2001-01-01

125

Simple effective interaction: Infinite nuclear matter and finite nuclei

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 ...

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

2013-01-01

126

Matter induced charge symmetry breaking and pion form factor in nuclear medium

Medium modification of pion form factor has been evaluated in asymmetric nuclear matter. It is shown that both the shape and the pole position of the pion form factor in dense asymmetric nuclear matter is different from its vacuum counterpart with $\\rho$-$\\omega$ mixing. This is due to the density and asymmetry dependent $\\rho$-$\\omega$ mixing which could even dominate over its vacuum counterpart in matter. Effect of the in-medium pion factor on experimental observables {\\it e.g.}, invariant mass distribution of lepton pairs has been demonstrated.

Roy, P; Sarkar, S; Alam, J; Roy, Pradip; Dutt-Mazumder, Abhee K.; Sarkar, Sourav; Alam, Jan-e

2006-01-01

127

Probing nuclear matter with jets

International Nuclear Information System (INIS)

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

128

Nuclear matter at finite temperature

International Nuclear Information System (INIS)

A method for deriving the equation of state of nuclear matter from realistic nucleon-nucleon potentials is studied. The author starts from a linked diagram expansion of the thermodynamic potential ?, and calculates ? by summing up its particle-particle and particle-hole ring diagrams each to all orders. A model-space finite temperature reaction matrix is introduced. As an intermediate step of his calculation, RPA-type secular equations need to be solved. These equations may have complex solutions, and the possibility that their occurrence may serve as a signal for phase transition is suggested. Results of a recent ring diagram calculation of nuclear matter at zero temperature using Paris and Reid potentials are discussed. 19 refs.; 11 figs

129

Quark matter and nuclear collisions

International Nuclear Information System (INIS)

I summarize briefly and qualitatively the content of my lectures. They treated on one hand quark deconfinement and its theoretical basis in finite temperature QCD, on the other hand high energy nuclear collisions as a way to produce a deconfined state of matter in the laboratory. The material presented will shortly appear in greater detail as a book under the same title as these lectures. (author)

130

BCS-BEC crossovers and unconventional phases in dilute nuclear matter. II

We study the phase diagram of isospin-asymmetrical nuclear matter in the density-temperature plane, allowing for four competing phases of nuclear matter: (i) the unpaired phase, (ii) the translationally and rotationally symmetric, but isospin-asymmetrical BCS condensate, (iii) the current-carrying Larkin-Ovchinnikov-Fulde-Ferrell phase, and (iv) the heterogeneous phase-separated phase. The phase diagram of nuclear matter composed of these phases features two tri-critical points in general, as well as crossovers from the asymmetrical BCS phase to a BEC of deuterons plus a neutron gas, both for the homogeneous superfluid phase (at high temperatures) and for the heterogeneous phase (at low temperatures). The BCS-BEC type crossover in the condensate occurs as the density is reduced. We analyze in detail some intrinsic properties of these phases, including the Cooper-pair wave function, the coherence length, the occupation numbers of majority and minority nucleonic components, and the dispersion relations of quasi...

Stein, Martin; Huang, Xu-Guang; Clark, John W

2014-01-01

131

International Nuclear Information System (INIS)

The spatio-temporal development of hadronic reactions was studied. This is in contrast with the usual S-matrix approach where only the asymptotic reaction products are considered. The crucial aspect is the Zeno effect modifying those interactions which take place in rapid succession. The time scales involved make the Zeno effect practically unobservable except at nuclear densities and above. After formulating the nature of the modifications, they are applied to hadronic cascades. A good fit is found for the data on pion production in hadron-nucleon collisions. The modifications due to the Zeno effect in relativistic many-body theory are demonstrated and the results are applied to the behavior of superdense matter in late stages of steller evolution. The Zeno effect leads to qualitative and quantitative changes in the predictions of the two theoretical models considered. Therefore, the Zeno effect must be incorporated in any calculation involving superdense matter

132

Hot nuclear matter with dilatons

International Nuclear Information System (INIS)

We study hot nuclear matter in a model based on nucleon interactions deriving from the exchange of scalar and vector mesons. The main new feature of our work is the treatment of the scale breaking of quantum chromodynamics by the introduction of a dilaton field. Although the dilaton effects are quite small quantitatively, they affect the high-temperature phase transition appreciably. We find that inclusion of the dilaton leads to a metastable high-density state at zero pressure, similar to that found by Glendenning who considered instead the admixture of higher baryon resonances. (orig.)

133

Charmed mesons in nuclear matter

We obtain the properties of charmed mesons in dense matter using a coupled-channel approach which accounts for Pauli blocking effects and meson self-energies in a self-consistent manner. We study the behaviour of dynamically-generated baryonic resonances together with the open-charm meson spectral functions in this dense nuclear environment. We discuss the implications of the in-medium properties of open-charm mesons on the $D_{s0}(2317)$ and the predicted X(3700) scalar resonances, and on the formation of $D$-mesic nuclei.

Tolos, L; Garcia-Recio, C; Oset, E; Molina, R; Nieves, J; Ramos, A

2010-01-01

134

Nuclear interactions and hadronic matter

International Nuclear Information System (INIS)

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

135

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

International Nuclear Information System (INIS)

We show that the relic abundance of the minority component of asymmetric dark matter can be very sensitive to the expansion rate of the Universe and the temperature of transition between a non-standard pre-Big Bang Nucleosynthesis cosmological phase and the standard radiation dominated phase, if chemical decoupling happens before this transition. In particular, because the annihilation cross section of asymmetric dark matter is typically larger than that of symmetric dark matter in the standard cosmology, the decrease in relic density of the minority component in non-standard cosmologies with respect to the majority component may be compensated by the increase in annihilation cross section, so that the annihilation rate at present of asymmetric dark matter, contrary to general belief, could be larger than that of symmetric dark matter in the standard cosmology. Thus, if the annihilation cross section of the asymmetric dark matter candidate is known, the annihilation rate at present, if detectable, could be used to test the Universe before Big Bang Nucleosynthesis, an epoch from which we do not yet have any data

136

A Dirac description of ¹S0+³ S1-³ D1 pairing in nuclear matter

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english We develop a Dirac-Hartree-Fock-Bogoliubov description of nuclear matter pairing in ¹S0 and ³S¹-³ D¹ channels. Here we investigate the density dependence ot the ¹S0 and ³S¹-³ D¹ pairing fields in asymmetric nuclear matter, using a Bonn meson-exchange interaction between Dirac nucleons. In this work, [...] we present preliminary results.

B. Funke, Haas; B. V., Carlson; Tobias, Frederico.

2004-09-01

137

Light Front Theory Of Nuclear Matter

A relativistic light front formulation of nuclear dynamics is applied to infinite nuclear matter. A hadronic meson-baryon Lagrangian, consistent with chiral symmetry, leads to a nuclear eigenvalue problem which is solved, including nucleon-nucleon (NN) correlations, in the one-boson-exchange approximation for the NN potential. The nuclear matter saturation properties are reasonably well reproduced, with a compression modulus of 180 MeV. We find that there are about 0.05 exce...

Miller, G. A.; Machleidt, R.

1998-01-01

138

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

139

Quasiparticle pole strength in nuclear matter

International Nuclear Information System (INIS)

It is argued that single-particle-like behavior in nuclear matter is much less probable than Brueckner theory suggests. In particular, the quasiparticle pole strength is evaluated for nuclear matter and it is shown that, contrary to the spirit of Brueckner theory, low momentum states play a crucial role in determining the magnitude of z/sub k/sub F/. (auth)

140

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

Kuwabara, H.; Hatsuda, T.

1995-01-01

141

Simple effective interaction: infinite nuclear matter and finite nuclei

The mean field properties and equation of state for asymmetric nuclear matter are studied 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 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 successful mean field models, as well as with the experimental data.

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

2013-09-01

142

Simple effective interaction: Infinite nuclear matter and finite nuclei

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

143

Holographic Symmetry Energy of the Nuclear Matter

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

Park, Chanyong

2011-01-01

144

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

145

Unifying Asymmetric Inert Fermion Doublet Dark Matter and Leptogenesis with Neutrino Mass

We propose a scalar Triplet extension of the standard model (SM) to unify the origin of neutrino mass with the visible and dark matter component of the Universe. We assume that the scalar triplet is super heavy, so that its CP-violating out-of-equilibrium decay in the early Universe not only produce asymmetric dark matter which is the neutral component of an additional vector like fermion doublet, but also give rise to lepton asymmetry. The latter gets converted to observed baryon asymmetry via B+L violating sphaleron processes. Below electroweak phase transition the scalar triplet acquires a vacuum expectation value and give rise to sub-eV Majorana masses to three flavors of active neutrinos. Thus an unification of the origin of neutrino mass, lepton asymmetry and asymmetric dark matter is achieved within a scalar triplet extension of the SM.

Sahu, Narendra

2012-01-01

146

Does asymmetric dark matter always lead to an anti-neutrino signal?

Under rather generic assumptions, we show that in the asymmetric dark matter (ADM) scenario, the sign of the B-L asymmetry stored in the dark matter sector and the standard model sector are always the same. One particularly striking consequence of this result is that, when the dark matter decays or annihilates in the present universe, the resulting final state always involves an anti-neutrino. As a concrete example of this, we construct a composite ADM model and explore the feasibility of detecting such an anti-neutrino signal in atmospheric neutrino detectors.

Fukuda, Hajime; Mukhopadhyay, Satyanarayan

2014-01-01

147

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

148

Lepton-Flavored Asymmetric Dark Matter and Interference in Direct Detection

In flavored dark matter models, dark matter can scatter off of nuclei through Higgs and photon exchange, both of which can arise from renormalizable interactions and individually lead to strong constraints from direct detection. While these two interaction channels can destructively interfere in the scattering amplitude, for a thermal relic with equal abundances for the dark matter particle and its antiparticle, this produces no effect on the total event rate. Focusing on lepton-flavored dark matter, we show that it is quite natural for dark matter to have become asymmetric during high-scale leptogenesis, and that in this case the direct detection bounds can be significantly weakened due to interference. We quantify this by mapping out and comparing the regions of parameter space that are excluded by direct detection for the symmetric and asymmetric cases of lepton-flavored dark matter. In particular, we show that the entire parameter region is ruled out for symmetric dark matter, while large portions of para...

Hamze, Ali; Koeller, Jason; Trendafilova, Cynthia; Yu, Jiang-Hao

2014-01-01

149

Asymmetric Dark Matter from Spontaneous Cogenesis in the Supersymmetric Standard Model

The observational relation between the density of baryon and dark matter in the Universe, $\\Omega_{\\rm DM}/\\Omega_B\\simeq 5$, 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 matte...

Kamada, Kohei

2012-01-01

150

Nucleons, mesons and deltas in nuclear matter

International Nuclear Information System (INIS)

Two subjects of interest are combined: the role of the ?-isobar in a nuclear medium together with the behaviour of nuclear matter far from saturation, particularly at high densities and temperatures. To study the influence of ?-states in nuclear matter a comparison has been made between a pure nucleonic model and a model that contains ? degrees of freedom. The free two-body OBE interactions are determined in Ch.2. The reduced coupled-channel Bethe-Salpeter equation is applied. A restriction is made to positive-energy baryonic states. The dynamical origin of the decay-width of the ? is examined. In Ch.3 the two-body potential is applied to infinite nuclear matter. The relativistic Dirac-Brueckner (DB) approach is used wherein also the ? degrees of freedom are incorporated. The nucleonic part of the model combines an accurate description of low-energy phase shifts with an adequate reproduction of the nuclear matter saturation properties. In Ch.4 the same approach is used to calculate the single-particle interaction of a nucleon with an energy above the nuclear-matter Fermi surface. It appears that the medium effects on 0566nucleon self-energy are important, therefore putting into question the applicability of the Relativistic Impulse Approximation in this energy area. In Ch.5 hot and dense matter is studied. The thermodynamical properties of nuclear matter is presented and also the temperature dependence of the single-particle potential of a nucleon in nuclear mattotential of a nucleon in nuclear matter. Temperature is included by means of the finite-temperature Green's function formalism for the nucleons. It turns out that the resulting set of Brueckner equations remains very similar to the T=0 case. (Auth.)

151

Variational theory of nuclear matter

International Nuclear Information System (INIS)

An overview of several different many-body theories is given and their predictions in the somewhat simpler systems of the 4He and 3He liquids and for a simple central potential model of nuclear matter are given. The variational theory is then developed. A generalized Jastrow product of two-body correlation functions containing central, spin, isospin, tensor, and spin-orbit operators is used. The correlation function is generated by a series of two-body Schroedinger equations. Expectation values with variational wave functions of the Jastrow type may be studied conveniently with generalized Mayer diagrams. Diagram rules are given and a general diagrammatic cluster expansion is derived. Evaluation of diagrams in the cluster expansion is complicated by the presence of the noncommuting operators. Some simple rules and useful methods for calculating the contribution due to the central, spin, isospin, and tensor operators are given. The development of single chain, hypernetted chain, and Fermi hypernetted chain (FHNC) equations for central correlations is reviewed. The chain summation methods are extended to sum single operator chains (SOC) for the noncentral operators. Methods are also given for treating the leading commutator corrections in the expansion by simple vertex factors. The energy expectation value for potentials with six operators are evaluated using the FHNC/SOC functions, with an exact treatment of the commutators involved. The energy isof the commutators involved. The energy is found to have a minimum with respect to variations in all parameters. Results of calculations with model potentials based on the Reid, Bethe-Johnson, Hamada-Johnston, and Gammel-Thaler potentials are reported

152

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

International Nuclear Information System (INIS)

The general class of 'Asymmetric Dark Matter (DM)' scenarios assumes the existence of a primordial particle/anti-particle asymmetry in the dark matter sector related to the asymmetry in the baryonic one, as a way to achieve the observed similarity between the baryonic and dark matter energy densities today. Focusing on this framework we study the effect of oscillations between dark matter and its anti-particle on the re-equilibration of the initial asymmetry. We calculate the evolution of the dark matter relic abundance and 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. We found in particular that a typical WIMP with a mass at the EW scale (about 1 TeV) having a primordial asymmetry of the same order as the baryon asymmetry, naturally gets the correct relic abundance if the ?m mass term is in the ? meV range. This turns out to be a natural value for fermionic DM arising from the higher dimensional operator H2DM2/? where H is the Higgs field and ? ? MPl. Finally, we constrain the parameter space in this framework by applying up-to-date bounds from indirect detection signals on annihilating DM

153

Thermal evolution of nuclear matter properties

International Nuclear Information System (INIS)

The study of equation of state (EOS) of nuclear matter (NM) as a function of temperature and density is a subject of renewed interest for its applications in the areas of high-energy heavy-ion (HI) collisions and in understanding astrophysical objects like supernova and neutron star matter

154

Nuclear shock waves and quark matter

International Nuclear Information System (INIS)

Atomic nuclei colliding with each other in a particle accelerator at extremely high velocities undergo interactions which lead to novel states of matter. The equation of state of this hot, dense nuclear matter reveals information on the processes occurring in a supernova, and on the big bang at the origin of the universe. (orig.)

155

Heavy Mesons in Nuclear Matter and Nuclei

Heavy mesons in nuclear matter and nuclei are analyzed within different frameworks, paying a special attention to unitarized coupled-channel approaches. Possible experimental signatures of the properties of these mesons in matter are addressed, in particular in connection with the future FAIR facility at GSI.

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

2014-01-01

156

Dark Matter Studies Entrain Nuclear Physics

We review theoretically well-motivated dark-matter candidates, and pathways to their discovery, in the light of recent results from collider physics, astrophysics, and cosmology. Taken in aggregate, these encourage broader thinking in regards to possible dark-matter candidates --- dark-matter need not be made of "WIMPs," i.e., elementary particles with weak-scale masses and interactions. Facilities dedicated to nuclear physics are well-poised to investigate certain non-WIMP ...

Gardner, Susan; Fuller, George

2013-01-01

157

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

International Nuclear Information System (INIS)

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

158

Cosmic ray-dark matter scattering: a new signature of (asymmetric) dark matter in the gamma ray sky

International Nuclear Information System (INIS)

We consider the process of scattering of Galactic cosmic-ray electrons and protons off of dark matter with the radiation of a final-state photon. This process provides a novel way to search for Galactic dark matter with gamma rays. We argue that for a generic weakly interacting massive particle, barring effects such as co-annihilation or a velocity-dependent cross section, the gamma-ray emission from cosmic-ray scattering off of dark matter is typically smaller than that from dark matter pair-annihilation. However, if dark matter particles cannot pair-annihilate, as is the case for example in asymmetric dark matter scenarios, cosmic-ray scattering with final state photon emission provides a unique window to detect a signal from dark matter with gamma rays. We estimate the expected flux level and its spectral features for a generic supersymmetric setup, and we also discuss dipolar and luminous dark matter. We show that in some cases the gamma-ray emission might be large enough to be detectable with the Fermi Large Area Telescope

159

Clusters in nuclear matter and Mott points

Light clusters (mass number $A \\leq 4$) in nuclear matter at subsaturation densities are described using a quantum statistical approach. In addition to self-energy and Pauli-blocking, effects of continuum correlations are taken into account to calculate the quasiparticle properties and abundances of light elements. Medium-modified quasiparticle properties are important ingredients to derive a nuclear matter equation of state applicable in the entire region of warm dense matter below saturation density. The influence of the nucleon-nucleon interaction on the quasiparticle shift is discussed.

Röpke, G

2015-01-01

160

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

DEFF Research Database (Denmark)

The SU(2) gauge theory with two massless Dirac flavors constitutes the building block of several models of Technicolor. Furthermore it has also been used as a template for the construction of a natural light asymmetric, or mixed type, dark matter candidate. We use explicit lattice simulations to confirm the pattern of chiral symmetry breaking by determining the Goldstone spectrum and therefore show that the dark matter candidate can, de facto, be constituted by a complex Goldstone boson. We also determine the phenomenologically relevant spin one and spin zero isovector spectrum and demonstrate that it is well separated from the Goldstone spectrum.

Lewis, Randy; Pica, Claudio

2012-01-01

161

Coupled Cluster studies of infinite nuclear matter

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

162

Nuclear matter in all its states

International Nuclear Information System (INIS)

This report includes the nine lectures which have been presented at the Joliot-Curie School of Nuclear Physics in 1985. The subjects covered are the following: thermodynamic description of excited nuclei; heavy ion reactions at high energy (theoretical approach); heavy ion reactions at high energy (experimental approach); relativistic nuclear physics and quark effects in nuclei; quark matter; nuclear compressibility and its experimental determinations; hot nuclei; anti p-nucleus interaction; geant resonances at finite temperature

163

A statistical model for hot nuclear matter

International Nuclear Information System (INIS)

We study the equation of state and the composition of nuclear matter at finite temperature with a grand canonical model which assumes nuclear statistical equilibrium. Matter is described as a thermodynamic ensemble of nucleons, photons, leptons and all possible nuclei. For the nucleons the relativistic mean field theory is used, the masses of the nuclei are taken from existing nuclear structure calculations, which were corrected for effects of finite temperature and the surrounding medium. The wide range of density, temperature and proton fractions which is present in type II supernovae explosions is analysed. Results for hot neutron stars and supernova explosions are presented, with emphasis on the liquid-gas phase transition region of nuclear matter, which can also be explored by heavy ion experiments

164

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

165

Big Bang Synthesis of Nuclear Dark Matter

We investigate the physics of dark matter models featuring composite bound states carrying a large conserved dark "nucleon" number. The properties of sufficiently large dark nuclei may obey simple scaling laws, and we find that this scaling can determine the number distribution of nuclei resulting from Big Bang Dark Nucleosynthesis. For plausible models of asymmetric dark matter, dark nuclei of large nucleon number, e.g. > 10^8, may be synthesised, with the number distribution taking one of two characteristic forms. If small-nucleon-number fusions are sufficiently fast, the distribution of dark nuclei takes on a logarithmically-peaked, universal form, independent of many details of the initial conditions and small-number interactions. In the case of a substantial bottleneck to nucleosynthesis for small dark nuclei, we find the surprising result that even larger nuclei, with size >> 10^8, are often finally synthesised, again with a simple number distribution. We briefly discuss the constraints arising from the...

Hardy, Edward; March-Russell, John; West, Stephen M

2014-01-01

166

Nuclear Pasta Matter for Different Proton Fractions

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

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

2014-01-01

167

Nuclear "pasta matter" for different proton fractions

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

Schuetrumpf, B.; Iida, K.; Maruhn, J. A.; Reinhard, P.-G.

2014-11-01

168

THE ENERGY GAP IN NUCLEAR MATTER

Energy Technology Data Exchange (ETDEWEB)

The magnitude of the energy gap in nuclear matter associated with a highly correlated ground state of the type believed to be important in the theory of superconductivity has been evaluated theoretically. The integral equation of Cooper, Mills, and Sessler is linearized and transformed into a form suitable for numerical solution. The energy gap, calculated by using an appropriate single-particle potential and the Gammel-Thaler two-body potential, is found to be a very strong function of the density of nuclear matter, and of the effective mass at the Fermi surface. It is concluded that the magnitude of the energy gap for nuclear matter should not be compared directly with experimental values for finite nuclei, although the results suggest that if the theory is extended to apply to finite nuclei it probably would be in agreement with experiment.

Emery, V.J.; Sessler, A.M.

1960-01-31

169

Nuclear matter in strong magnetic fields

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

Diener, J P W

2013-01-01

170

Resummations and chiral dynamics of nuclear matter

International Nuclear Information System (INIS)

The equation of state of isospin-symmetric nuclear matter and pure neutron matter is calculated to three-loop order with in-medium chiral perturbation theory, taking into account also two-pion exchange with ?-isobar excitations. The large empirical S-wave NN-scattering lengths, as=19 fm and at=-5.4 fm, require a non-perturbative treatment via a resummation of ladder diagrams to all orders. Our resummation method includes (combined) particle-particle and hole-hole rescatterings in the medium. The remaining short range part of the interaction is described by adjustable (p2-dependent) NN-contact terms. In this framework the saturation properties of symmetric nuclear matter can be well reproduced and the nuclear matter compressibility takes on an improved value in comparison to earlier calculations without resummations. The neutron matter equation of state is particularly improved by the resummations. At low densities the energy per particle follows one half of the kinetic energy, which is a feature of the unitary Fermi gas. The results of sophisticated neutron matter calculations can be reproduced up to high neutron densities ?n=0.4 fm3.

171

Holographic cold nuclear matter and neutron star

We have previously found a new phase of cold nuclear matter based on a holographic gauge theory, where baryons are introduced as instanton gas in the probe D8/$\\overline{\\rm D8}$ branes. In our model, we could obtain the equation of state (EOS) of our nuclear matter by introducing fermi momentum. Then, here we apply this model to the neutron star and study its mass and radius by solving the Tolman-Oppenheimer-Volkoff (TOV) equations in terms of the EOS given here. We give so...

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

2013-01-01

172

Transport properties of ?-stable nuclear matter

International Nuclear Information System (INIS)

The transport properties of matter in the interior of rotating neutron stars play a critical role in determining the evolution of these compact objects. In this brief report we discuss a study of the shear viscosity of stellar matter composed by neutrons, protons and electrons in equilibrium with respect to ? decay and electronic capture. The aim of this work is calculate in a fully consistent manner the equation of state and the transport properties of nuclear matter, in particular the shear viscosity coefficient, using the same dynamical model.

173

The exploration of hot nuclear matter.

When nuclear matter is heated beyond 2 trillion degrees, it becomes a strongly coupled plasma of quarks and gluons. Experiments using highly energetic collisions between heavy nuclei have revealed that this new state of matter is a nearly ideal, highly opaque liquid. A description based on string theory and black holes in five dimensions has made the quark-gluon plasma an archetypical strongly coupled quantum system. Open questions about the structure and theory of the quark-gluon plasma are under active investigation. Many of the insights are also relevant to ultracold fermionic atoms and strongly correlated condensed matter. PMID:22822143

Jacak, Barbara V; Müller, Berndt

2012-07-20

174

New type of Pairing interactions in nuclear matter and finite nuclei

Energy Technology Data Exchange (ETDEWEB)

We propose new types of density dependent contact pairing interaction which reproduce pairing gaps in a wide range of nuclear mass table. We discuss also the relation between the proposed paring interactions and the pairing gaps in symmetric and neutron matters obtained by a microscopic treatment based on a bare nucleon-nucleon interaction. It is shown that the isovector type pairing interaction is necessary on top of the isoscalar term to reproduce systematically nuclear empirical pairing gaps. The BCS-BEC crossover of neutrons pairs in symmetric and asymmetric nuclear matters is studied by using these contact interactions. It is shown that the bare and screened pairing interactions lead to different features of the BCS-BEC crossover in symmetric nuclear matter.

Sagawa, H [Center for Mathematics and Physics, University of Aizu, Aizu-Wakamatsu, 965-8580 Fukushima (Japan); Margueron, J [Institut de Physique Nucleaire, Universite Paris-Sud, IN2P3-CNRS, F-91406 Orsay Cedex (France); Hagino, K, E-mail: sagawa@u-aizu.ac.jp [Department of Physics, Tohoku University, Sendai, 980-8578 (Japan)

2011-09-16

175

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, Bo

2007-01-01

176

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

177

Nuclear physics of hot dense matter

International Nuclear Information System (INIS)

The equation of state of hot dense matter is an essential ingredient to describe the gravitational contraction of massive stars. Some of the nuclear physics problems occurring in the determination of the equation of state of hot dense matter are discussed. This particularly rich domain of nuclear physics deals with very unusual nuclei, whose mass numbers can be sometimes as large as a thousand, whose existence becomes possible in dense matter because of the screening of Coulomb forces. A calculation of the properties of hot nuclear matter in the mean field approximation is presented. It is shown that a useful approximation to study the phase equilibrium equations is to consider low temperature expansions for the nucleus expansions for the vapor. A simple formula is derived for the limiting temperature TL beyond which nuclei no longer exist. The equation of state is discussed at subnuclear density and in the domain densities greater than the nuclear saturation density. The standard methods of non relativistic many-body theory as well as relativistic mean-field and Dirac-Brueckner approaches are also discussed. (K.A.) 70 refs., 9 figs

178

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.)

179

Nuclear matter in heavy ion collisions

International Nuclear Information System (INIS)

In this report the measurement of the inclusive production of negative pions and protons in reactions of 40Ar with KCl at 1.8 GeV/nucleon is described. The measured energy spectra and multiplicities are presented and discussed regarding the stopping power of nuclear matter. (HSI)

180

Analogies between nuclear physics and Dark Matter

A fermionic description of dark matter using analogies with nuclear physics is developed. At tree level, scalar and vector processes are considered and the two-body potential are explicitly calculated using the Breit approximation. We show that the total cross sections in both cases exhibit Sommerfeld enhancement.

Carcamo, Dante; Gamboa, Jorge

2014-01-01

181

Analogies between nuclear physics and dark matter

A fermionic description of dark matter using analogies with nuclear physics is developed. At tree level, scalar and vector processes are considered and the two-body potential are explicitly calculated using the Breit approximation. We show that the total cross-sections in both cases exhibit Sommerfeld enhancement.

Cárcamo, D.; Riveros, A.; Gamboa, J.

2014-12-01

182

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.

183

Probing Cold Dense Nuclear Matter

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

Subedi, R; Monaghan, P; Anderson, B D; Aniol, K; Annand, J; Arrington, J; Benaoum, H; Benmokhtar, F; Bertozzi, W; Boeglin, W; Chen, J -P; Choi, Seonho; Cisbani, E; Craver, B; Frullani, S; Garibaldi, F; Gilad, S; Gilman, R; Glamazdin, O; Hansen, J -O; Higinbotham, D W; Holmstrom, T; Ibrahim, H; Igarashi, R; De Jager, C W; Jans, E; Jiang, X; Kaufman, L; Kelleher, A; Kolarkar, A; Kumbartzki, G; LeRose, J J; Lindgren, R; Liyanage, N; Margaziotis, D J; Markowitz, P; Marrone, S; Mazouz, M; Meekins, D; Michaels, R; Moffit, B; Perdrisat, C F; Piasetzky, E; Potokar, M; Punjabi, V; Qiang, Y; Reinhold, J; Ron, G; Rosner, G; Saha, A; Sawatzky, B; Shahinyan, A; Širca, S; Slifer, K; Solvignon, P; Sulkosky, V; Urciuoli, G; Voutier, E; Watson, J W; Weinstein, L B; Wojtsekhowski, B; Wood, S; Zheng, X -C; Zhu, L; 10.1126/science.1156675

2009-01-01

184

String dynamics in nuclear matter

International Nuclear Information System (INIS)

Hadron production in soft hadronic collisions is successfully described by a longitudinal excitation and subsequent decay of color flux tubes. We consider the dynamics of interacting unstable strings as a generalization designed for hA and AA interactions at ultrarelativistic energies. The constituent quarks at the ends of the decaying strings and the produced hadrons can interact with their surrounding matter. The effect of secondary interactions in molecular dynamics calculations for AA collisions at CERN energies (200 AGeV) can be seen - most clearly in central collisions - in an enhancement of transverse energy, particle production and the mean transverse momenta. The results agree very well with the experimental measurements at ultrarelativistic beam energies in pp, hA and the recent AA collisions. (orig.)

185

The modulation effect for supersymmetric dark matter detection with asymmetric velocity dispersion

The detection of the theoretically expected dark matter is central to particle physics cosmology. Current fashionable supersymmetric models provide a natural dark matter candidate which is the lightest supersymmetric particle (LSP). Such models combined with fairly well understood physics like the quark substructure of the nucleon and the nuclear form factor and the spin response function of the nucleus, permit the evaluation of the event rate for LSP-nucleus elastic scatter...

Vergados, J. D.

2000-01-01

186

D-mesons and charmonium states in hot isospin asymmetric strange hadronic matter

International Nuclear Information System (INIS)

The study of the medium modifications of hadrons is an important topic of research in strong interaction physics, which is of relevance in the heavy-ion collision experiments as well as in nuclear astrophysics. The study of the mass modifications of D mesons is relevant in understanding their production as well as collective flow in the heavy-ion collision experiments. The present paper is devoted to the study of medium modifications of D mesons in isospin asymmetric strange hadronic medium at finite temperatures

187

BCS-BEC crossovers and unconventional phases in dilute nuclear matter

We study the phase diagram of isospin-asymmetrical nuclear matter in the density-temperature plane, allowing for four competing phases of nuclear matter: (i) the unpaired phase; (ii) the translationally and rotationally symmetric, but isospin-asymmetrical BCS condensate; (iii) the current-carrying Larkin-Ovchinnikov-Fulde-Ferrell phase; and (iv) the heterogeneous phase-separated phase. The phase diagram of nuclear matter composed of these phases features two tricritical points, in general, as well as crossovers from the asymmetrical BCS phase to a Bose-Einstein condensate (BEC) of deuterons plus a neutron gas, for both the homogeneous superfluid phase (at high temperatures) and the heterogeneous phase (at low temperatures). The BCS-BEC-type crossover in the condensate occurs as the density is reduced. We analyze in detail some intrinsic properties of these phases, including the Cooper-pair wave function, the coherence length, the occupation numbers of majority and minority nucleonic components, and the dispersion relations of quasiparticle excitations about the ground state. We show by explicit examples that the physics of the individual phases and the transition from weak to strong coupling can be well understood by tracing the behavior of these quantities.

Stein, Martin; Sedrakian, Armen; Huang, Xu-Guang; Clark, John W.

2014-12-01

188

Chiral density wave in nuclear matter

Inspired by recent work on inhomogeneous chiral condensation in cold, dense quark matter within models featuring quark degrees of freedom, we investigate the chiral density-wave solution in nuclear matter at zero temperature and nonvanishing baryon number density in the framework of the so-called extended linear sigma model (eLSM). The eLSM is an effective model for the strong interaction based on the global chiral symmetry of quantum chromodynamics (QCD). It contains scalar, pseudoscalar, vector, and axial-vector mesons as well as baryons. In the latter sector, the nucleon and its chiral partner are introduced as parity doublets in the mirror assignment. The eLSM simultaneously provides a good description of hadrons in vacuum as well as nuclear matter ground-state properties. We find that an inhomogeneous phase in the form of a chiral density wave is realized, but only for densities larger than 2.4?0, where ?0 is the nuclear matter ground-state density.

Heinz, Achim; Giacosa, Francesco; Rischke, Dirk H.

2015-01-01

189

D-mesons and charmonium states in hot isospin asymmetric strange hadronic matter

Energy Technology Data Exchange (ETDEWEB)

We study the properties of D and anti D mesons in hot isospin asymmetric strange hadronic matter, arising due to their interactions with the hadrons in the hyperonic medium. The interactions of D and anti D mesons with these light hadrons are derived by generalizing the chiral SU(3) model used for the study of hyperonic matter to SU(4). The nucleons, hyperons, the scalar isoscalar meson, {sigma} and the scalar-isovector meson, {delta} as modified in the strange hadronic matter, modify the masses of D and anti D mesons. It is found that, as compared to the anti D mesons (anti D{sup 0}, D{sup -}), the properties of the D mesons (D{sup 0}, D {sup +}) are more sensitive to the isospin asymmetry at high densities. On the other hand, the effects of strangeness fraction are found to be more dominant for the anti D mesons as compared to the D mesons and these modifications are observed to be particularly appreciable at high densities. We also study the mass modifications of the charmonium states J/{psi}, {psi}(3686) and {psi}(3770) in the isospin asymmetric strange hadronic matter at finite temperatures and investigate the possibility of the decay of the charmonium states into D anti D pairs in the hot hadronic medium. The mass modifications of these charmonium states arise due to their interaction with the gluon condensates of QCD, simulated by a scalar dilaton field introduced to incorporate the broken scale invariance of QCD within the effective chiral model. The effects of finite quark masses are taken into account in the trace of the energy momentum tensor in QCD, while investigating the medium modification of the charmonium masses through the modification of the gluon condensate in the medium. We also compute the partial decay widths of the charmonium states to the D anti D pairs in the hadronic medium. The strong dependence on density of the in-medium properties of the D, anti D and the charmonium states, as well as the partial decay widths of charmonium states to D anti D pairs, found in the present investigation, will be of direct relevance in observables like open charm enhancement as well as J/{psi} suppression in the compressed baryonic matter (CBM) experiments at the future Facility for Antiproton and Ion Research, GSI, where the baryonic matter at high densities is planned to be produced. (orig.)

Kumar, Arvind; Mishra, Amruta [Indian Institute of Technology, Delhi, Hauz Khas, Department of Physics, New Delhi (India)

2011-12-15

190

Wanted! Nuclear Data for Dark Matter Astrophysics

Astronomical observations from small galaxies to the largest scales in the universe can be consistently explained by the simple idea of dark matter. The nature of dark matter is however still unknown. Empirically it cannot be any of the known particles, and many theories postulate it as a new elementary particle. Searches for dark matter particles are under way: production at high-energy accelerators, direct detection through dark matter-nucleus scattering, indirect detection through cosmic rays, gamma rays, or effects on stars. Particle dark matter searches rely on observing an excess of events above background, and a lot of controversies have arisen over the origin of observed excesses. With the new high-quality cosmic ray measurements from the AMS-02 experiment, the major uncertainty in modeling cosmic ray fluxes is in the nuclear physics cross sections for spallation and fragmentation of cosmic rays off interstellar hydrogen and helium. The understanding of direct detection backgrounds is limited by poor knowledge of cosmic ray activation in detector materials, with order of magnitude differences between simulation codes. A scarcity of data on nucleon spin densities blurs the connection between dark matter theory and experiments. What is needed, ideally, are more and better measurements of spallation cross sections relevant to cosmic rays and cosmogenic activation, and data on the nucleon spin densities in nuclei.

Gondolo, P.

2014-06-01

191

Nucleon properties inside compressed nuclear matter

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

Rozynek, Jacek

2014-01-01

192

Relativistic calculation of polarized nuclear matter

International Nuclear Information System (INIS)

The binding energy of nuclear matter with excess of neutrons, of spin-up neutrons, and spin-up protons contains three symmetry energies: the isospin symmetry energy epsilonsub(tau), the spin symmetry energy epsilonsub(sigma), and the spin-isospin symmetry energy epsilonsub(sigmatau). Relativistic correction to the non-relativistic Skyrme effective interaction to order 1/c2 is used in order to calculate the relativistic corrections for the binding energy of polarized nuclear matter. The relativistic corrections to epsilonsub(tau), epsilonsub(sigma) and epsilonsub(sigmatau) are found to be -2.06, -2.6 and -0.89 MeV respectively. The relativistic correction to the compression modulus is -10.8 MeV. (author)

193

Thermodynamic consistency for nuclear matter calculations

We investigate the relation between the binding energy and the Fermi energy and between different expressions for the pressure in cold nuclear matter. For a self-consistent calculation based on a $\\Phi$ derivable $T-$matrix approximation with off-shell propagators the thermodynamic relations are well satisfied unlike for a $G-$matrix or a $T-$matrix approach using quasi-particle propagators in the ladder diagrams.

Bozek, P

2001-01-01

194

Chiral density wave in nuclear matter

Inspired by recent work on inhomogeneous chiral condensation in cold, dense quark matter within models featuring quark degrees of freedom, we investigate the chiral density-wave solution in nu- clear matter at zero temperature and nonvanishing baryon number density in the framework of the so-called extended linear sigma model (eLSM). The eLSM is an effective model for the strong interaction based on the global chiral symmetry of quantum chromodynamics (QCD). It contains scalar, pseudoscalar, vector, and axial-vector mesons as well as baryons. In the latter sector, the nucleon and its chiral partner are introduced as parity doublets in the mirror assignment. The eLSM simultaneously provides a good description of hadrons in vacuum as well as nuclear matter ground-state properties. We find that an inhomogeneous phase in the form of a chiral density wave is realized, but only for densities larger than 2.4 {\\rho}0, where {\\rho}0 is the nuclear matter ground-state density.

Heinz, Achim; Rischke, Dirk H

2013-01-01

195

A Naturally Light Sterile neutrino in an Asymmetric Dark Matter Model

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

196

Charge-dependent directed flow in asymmetric nuclear collisions

The directed flow of identified hadrons is studied within the parton-hadron-string-dynamics (PHSD) approach for the asymmetric system Cu+Au in non-central collisions at $\\sqrt{s_{NN}}$ = 200 GeV. It is emphasized that due to the difference in the number of protons of the colliding nuclei an electric field emerges which is directed from the heavy to the light nucleus. This strong electric field is only present for about 0.25 fm/c at $\\sqrt{s_{NN}}$ = 200 GeV and leads to a splitting of the directed flow $v_1$ for particles with the same mass but opposite electric charges in case of an early presence of charged quarks and antiquarks. The microscopic calculations of the directed flow for $\\pi^\\pm, K^\\pm, p$ and $\\bar{p}$ are carried out in the PHSD by taking into account the electromagnetic field induced by the spectators as well as its influence on the hadronic and partonic quasiparticle trajectories. It is shown that the splitting of the directed flow as a function of pseudorapidity $\\eta$ and in particular as...

Voronyuk, V; Voloshin, S A; Cassing, W

2014-01-01

197

Charge-dependent directed flow in asymmetric nuclear collisions

The directed flow of identified hadrons is studied within the parton-hadron-string-dynamics (PHSD) approach for the asymmetric system Cu + Au in noncentral collisions at ?{sNN}=200 GeV. It is emphasized that due to the difference in the number of protons of the colliding nuclei an electric field emerges, which is directed from the heavy to the light nucleus. This strong electric field is only present for about 0.25 fm/c at ?{sNN}=200 GeV and leads to a splitting of the directed flow v1 for particles with the same mass but opposite electric charges in case of an early presence of charged quarks and antiquarks. The microscopic calculations of the directed flow for ?±,K±,p , and p ¯ are carried out in the PHSD by taking into account the electromagnetic field induced by the spectators as well as its influence on the hadronic and partonic quasiparticle trajectories. It is shown that the splitting of the directed flow as a function of pseudorapidity ? and in particular as a function of the transverse momentum pt provides a direct access to the electromagnetic response of the very early (nonequilibrium) phase of relativistic heavy-ion collisions and allows us to shed light on the presence (and number) of electric charges in this phase.

Voronyuk, V.; Toneev, V. D.; Voloshin, S. A.; Cassing, W.

2014-12-01

198

History of the nuclear matter safety and control law

International Nuclear Information System (INIS)

In this text we give the history of the law creation on the control and safety of nuclear matter. Initially based on the CEA regulation single owner of nuclear matter, the development of nuclear energy has conducted the French government to edict law in relation with IAEA and Euratom recommendations

199

Spin-asymmetry energy of nuclear matter

We calculate the density-dependent spin-asymmetry energy $S(k_f)$ of isospin-symmetric nuclear matter in the three-loop approximation of chiral perturbation theory. The interaction contributions to $S(k_f)$ originate from one-pion exchange, iterated one-pion exchange, and (irreducible) two-pion exchange with no, single, and double virtual $\\Delta$-isobar excitation. We find that the truncation to $1\\pi$-exchange and iterated $1\\pi$-exchange terms (which leads already to a go...

Kaiser, N.

2004-01-01

200

Is nuclear matter a quantum crystal?

A possible alternative to the ordinary gas-like computation for nuclear matter is investigated under the assumption that the nucleons are arranged in a lattice. BCC, FCC and HCP structures are investigated. Only HCP shows a minimum in the energy vs. density curve with a modest binding energy of -1.5 MeV. The very low density limit is investigated and sensible results are obtained only if the tensor force decreases with the density. A study of the elastic properties indicates that the previous structures are mechanically unstable against shearing stresses.

Canuto, V.; Chitre, S. M.

1973-01-01

201

Chiral symmetry, strangeness and nuclear matter

International Nuclear Information System (INIS)

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. (orig.)

202

Nuclear interaction rates for dark matter detectors

International Nuclear Information System (INIS)

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

203

Strange mesons in dense nuclear matter

International Nuclear Information System (INIS)

Experimental data on the production of kaons and antikaons in heavy ion collisions at relativistic energies are reviewed with respect to in-medium effects. The K-/K+ ratios measured in nucleus-nucleus collisions are 1-2 orders of magnitude larger than in proton-proton collisions. The azimuthal angle distributions of K+ mesons indicate a repulsive kaon-nucleon potential. Microscopic transport calculations consistently explain both the yields and the emission patterns of kaons and antikaons when assuming that their properties are modified in dense nuclear matter. The K+ production excitation functions measured in light and heavy collision systems provide evidence for a soft nuclear equation-of-state. (orig.)

204

Incomprehensibility in finite nuclei and nuclear matter

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

Stone, J R; Moszkowski, S A

2014-01-01

205

Particle-Hole States in Nuclear Matter.

This work deals with the collective excitations in nuclear matter, from the point of view of the TDA approximation. Our calculations involved the construction of a Hamiltonian, expressed as a matrix in the space of particle-hole excitations with a given momentum transfer. We used in this Hamiltonian an average single nucleon potential, and (in some cases) an effective interaction obtained for the potential HEA in the relativistic Brueckner -Hartree Fock theory. The eigenvectors of the TDA-Hamiltonian were used to compute the strength of the collective response of nuclear matter to external probes. Our results, succinctly described in the last section, are summarized in a set of figures at the end of this monograph. The basic features of the Brueckner theory needed for our work are presented in the last chapter. The relativistic corrections that we have introduced are discussed in a paper by M. R. Anastasio, L. S. Celenza, W. S. Pong, and C. M. Shakin on Relativistic Nuclear Structure (see Ref 9 in dissertation). The specific form of the TDA equations that we used, and the procedure to calculate the degree of collectivity of the solutions, is studied in detail in the fifth chapter. A derivation of the TDA equations, and a discussion of the solutions for a separable potential, is given in the fourth chapter. The structure of a non-relativistic potential for a system of two nucleons is examined in the third chapter, in several representations. On the other hand, the particle -hole states relevant to our discussions on the TDA equations are introduced in the first two chapters.

Matyas, Carl A.

206

Hirschegg '95: Dynamical properties of hadrons in nuclear matter. Proceedings

International Nuclear Information System (INIS)

The following topics were dealt with: Chiral symmetry, chiral condensates, in-medium effective chiral Lagrangians, ?'s in nuclei, nonperturbative QCD, electron scattering from nuclear matter, nuclear shadowing, QCD sum rules, deconfinement, ultrarelativistic heavy ion collisions, nuclear dimuon and electron pair production, photoproduction from nuclei, subthreshold K+ production, kaon polarization in nuclear matter, charged pion production in relativistic heavy ion collisions, the Nambu-Jona-Lasinio model, the SU(3)LxSU(3)R sigma model, nonequilibrium dense nuclear matter, pion pair production at finite temperature. (HSI)

207

Bulk Properties of Symmetric Nuclear and Pure Neutron Matter

Directory of Open Access Journals (Sweden)

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

Khaled Hassaneen

2013-05-01

208

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

Dark matter (DM) with sizeable self-interactions mediated by a light species offers a compelling explanation of the observed galactic substructure; furthermore, the direct coupling between DM and a light particle contributes to the DM annihilation in the early universe. If the DM abundance is due to a dark particle-antiparticle asymmetry, the DM annihilation cross-section can be arbitrarily large, and the coupling of DM to the light species can be significant. We consider the case of asymmetric DM interacting via a light (but not necessarily massless) Abelian gauge vector boson, a dark photon. In the massless dark photon limit, gauge invariance mandates that DM be multicomponent, consisting of positive and negative dark ions of different species which partially bind in neutral dark atoms. We argue that a similar conclusion holds for light dark photons; in particular, we establish that the multi-component and atomic character of DM persists in much of the parameter space where the dark photon is sufficiently l...

Petraki, Kalliopi; Kusenko, Alexander

2014-01-01

209

Relativistic calculation of polarized nuclear matter

International Nuclear Information System (INIS)

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

210

On the thermal properties of polarised nuclear matter

International Nuclear Information System (INIS)

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

211

Nuclear matter structure studied with quantum molecular dynamics

Quantum molecular dynamics is applied to study the ground state properties of nuclear matter at subsaturation densities. Clustering effects are observed as to soften the equation of state at these densities. The structure of nuclear matter at subsaturation density shows some exotic shapes with variation of the density.

Maruyama, T; Oyamatsu, K; Maruyama, T; Chiba, S; Iwamoto, A

1999-01-01

212

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)

213

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)

214

Phase transitions in nuclear matter and consequences for neutron stars

International Nuclear Information System (INIS)

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

215

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-nuclear-hole states in nuclear matter are included. The ?-meson self enery 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.)

216

Properties of the cloudy bag in nuclear matter

International Nuclear Information System (INIS)

Softening of the pion mode in nuclear matter with increase of its density leads to a rise in the pion field of the cloudy bag in the nuclear medium. This in turn leads to a decrease of the size of the bag, and for a sufficiently high density of the medium it leads to absolute instability of the cloudy-bag nucleon, which means the transition of nuclear matter to a different, non-nucleon phase

217

Isospin Violating Dark Matter Search by Nuclear Emulsion Detector

Dark matter signal and its annual modulation of event number are observed by some direct searches in small mass region. However, the regions have been excluded by others. The isospin-violating dark matter is a hopeful candidate to explain the discrepancy. We study the possibility that a future project of dark matter search using nuclear emulsion can reach favored region by the isospin-violating dark matter. Since the detector has the directional sensitivity, it is expected t...

Nagao, Keiko I.; Naka, Tatsuhiro

2012-01-01

218

Isospin-violating dark matter search by nuclear emulsion detector

The dark matter signal and its annual modulation of event number are observed by some direct searches. However, these parameter spaces have been excluded by other experiments. Isospin-violating dark matter is a hopeful candidate to solve the discrepancy. We study the possibility that a future dark matter search project using nuclear emulsion can reach the region favored by the isospin-violating dark matter. Since the detector has directional sensitivity, it is expected to examine the region including the modulation property.

Nagao, Keiko I.; Naka, Tatsuhiro

2013-04-01

219

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

International Nuclear Information System (INIS)

We consider SUSY-like missing energy events at hadron colliders and critically examine the common assumption that the missing energy is the result of two identical missing particles. In order to experimentally test this hypothesis, we generalize the subsystem MT2 variable to the case of asymmetric event topologies, where the two SUSY decay chains terminate in different 'children' particles. In this more general approach, the endpoint MT2(max) of the MT2 distribution now gives the mass (tilde M)p((tilde M)c(a), (tilde M)c(b)) of the parent particles as a function of two input children masses (tilde M)c(a) and (tilde M)c(b). We propose two methods for an independent determination of the individual children masses Mc(a) and Mc(b). First, in the presence of upstream transverse momentum PUTM the corresponding function (tilde M)p((tilde M)c(a), (tilde M)c(b), PUTM) is independent of PUTM at precisely the right values of the children masses. Second, the previously discussed MT2 'kink' is now generalized to a 'ridge' on the 2-dimensional surface (tilde M)p((tilde M)c(a), (tilde M)c(b)). As we show in several examples, quite often there is a special point along that ridge which marks the true values of the 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.

220

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

Dark matter (DM) with sizeable self-interactions mediated by a light species offers a compelling explanation of the observed galactic substructure; furthermore, the direct coupling between DM and a light particle contributes to the DM annihilation in the early universe. If the DM abundance is due to a dark particle-antiparticle asymmetry, the DM annihilation cross-section can be arbitrarily large, and the coupling of DM to the light species can be significant. We consider the case of asymmetric DM interacting via a light (but not necessarily massless) Abelian gauge vector boson, a dark photon. In the massless dark photon limit, gauge invariance mandates that DM be multicomponent, consisting of positive and negative dark ions of different species which partially bind in neutral dark atoms. We argue that a similar conclusion holds for light dark photons; in particular, we establish that the multi-component and atomic character of DM persists in much of the parameter space where the dark photon is sufficiently light to mediate sizeable DM self-interactions. We discuss the cosmological sequence of events in this scenario, including the dark asymmetry generation, the freeze-out of annihilations, the dark recombination and the phase transition which gives mass to the dark photon. We estimate the effect of self-interactions in DM haloes, taking into account this cosmological history. We place constraints based on the observed ellipticity of large haloes, and identify the regimes where DM self-scattering can affect the dynamics of smaller haloes, bringing theory in better agreement with observations. Moreover, we estimate the cosmological abundance of dark photons in various regimes, and derive pertinent bounds.

Petraki, Kalliopi; Pearce, Lauren; Kusenko, Alexander

2014-07-01

221

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

222

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

223

QMD application of sub-saturated nuclear matter

Energy Technology Data Exchange (ETDEWEB)

QMD (quantum molecular dynamics) has not been applied to supernova and neutron star matter. We begun to apply QMD, microscopic simulation of nuclear reaction, to the infinite system of nuclear matter. The infinite system was simulated by N particles system under the periodic boundary condition. Pauli potential introduced repulsive force which the same kinds of particles could not approach at phase space, instead of antisymmetrization of the system. Supernova matter was appropriate to the symmetric nuclear matter, the inhomogeneous structure was observed less than 0.8 {rho}{sub 0} of density, but homogeneous more than it. Each nucleus was seen to separate from others less than 0.2 {rho}{sub 0}. Neutron star matter attains {beta} equilibrium and not symmetric matter and the lowest energy was obtained at about 0.03-0.08 of proton content. (S.Y.)

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

1997-05-01

224

Antikaons in infinite nuclear matter and nuclei

Energy Technology Data Exchange (ETDEWEB)

In this work we studied the properties of antikaons and hyperons in infinite cold nuclear matter. The in-medium antikaon-nucleon scattering amplitude and self-energy has been calculated within a covariant many-body framework in the first part. Nuclear saturation effects have been taken into account in terms of scalar and vector nucleon mean-fields. In the second part of the work we introduced a non-local method for the description of kaonic atoms. The many-body approach of anti KN scattering can be tested by the application to kaonic atoms. A self-consistent and covariant many-body approach has been used for the determination of the antikaon spectral function and anti KN scattering amplitudes. It considers s-, p- and d-waves and the application of an in-medium projector algebra accounts for proper mixing of partial waves in the medium. The on-shell reduction scheme is also implemented by means of the projector algebra. The Bethe-Salpeter equation has been rewritten, so that the free-space anti KN scattering can be used as the interaction kernel for the in-medium scattering equation. The latter free-space scattering is based on a realistic coupled-channel dynamics and chiral SU(3) Lagrangian. Our many-body approach is generalized for the presence of large scalar and vector nucleon mean-fields. It is supplemented by an improved renormalization scheme, that systematically avoids the occurrence of medium-induced power-divergent structures and kinematical singularities. A modified projector basis has been introduced, that allows for a convenient inclusion of nucleon mean-fields. The description of the results in terms of the 'physical' basis is done with the help of a recoupling scheme based on the projector algebra properties. (orig.)

Moeller, M.

2007-12-10

225

International Nuclear Information System (INIS)

Nuclear matter and ground state properties for (proton and neutron) semi-closed shell nuclei are described in relativistic mean field theory with coupling constants which depend on the vector density. The parametrization of the density dependence for ?-, ?- and ?-mesons is obtained by fitting to properties of nuclear matter and some finite nuclei. The equation of state for symmetric and asymmetric nuclear matter is discussed. Finite nuclei are described in Hartree approximation, including a charge and an improved center-of-mass correction. Pairing is considered in the BCS approximation. Special attention is directed to the predictions for properties at the neutron and proton driplines, e.g. for separation energies, spin-orbit splittings and density distributions. (orig.)

226

Energy Technology Data Exchange (ETDEWEB)

Nuclear matter and ground state properties for (proton and neutron) semi-closed shell nuclei are described in relativistic mean field theory with coupling constants which depend on the vector density. The parametrization of the density dependence for {sigma}-, {omega}- and {rho}-mesons is obtained by fitting to properties of nuclear matter and some finite nuclei. The equation of state for symmetric and asymmetric nuclear matter is discussed. Finite nuclei are described in Hartree approximation, including a charge and an improved center-of-mass correction. Pairing is considered in the BCS approximation. Special attention is directed to the predictions for properties at the neutron and proton driplines, e.g. for separation energies, spin-orbit splittings and density distributions. (orig.)

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

1998-06-01

227

Exploring compressed nuclear matter with HADES

International Nuclear Information System (INIS)

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

228

Kaons in nuclear matter; Kaonen in Kernmaterie

Energy Technology Data Exchange (ETDEWEB)

The subject of the doctoral thesis is examination of the properties of kaons in nuclear matter. A specific method is explained that has been developed for the scientific objectives of the thesis and permits description of the kaon-nucleon interactions and kaon-nucleon scattering in a vacuum. The main challenge involved was to find approaches that would enable application of the derived relations out of the kaon mass shell, connected with the second objective, namely to possibly find methods which are independent of models. The way chosen to achieve this goal relied on application of reduction formulas as well as current algebra relations and the PCAC hypothesis. (orig./CB) [Deutsch] Die Arbeit befasst sich mit der Untersuchung der Eigenschaften von Kao nen in Kernmaterie. Zu diesem Zweck wurde ein Verfahren entwickelt, di e Kaon- Nukleon- Wechselwirkung und Kaon- Nukleon- Streuung im Vakuumzu beschreiben. Die Hauptherausforderung bestand darin, dass die abgel eiteten Relationen ausserhalb der Kaonen- Massenschale anwendbar werde n. Eine Nebenforderung war, dass die vorgeschlagenen Verfahren moeglic hst modell- unabhaengig sind. Um dieses Ziel zu erreichen, wurden Redu ktionsformeln, Stromalgebra- Relationen und die PCAC- Hypothese angewe ndet.

Kolomeitsev, E.E.

1997-02-01

229

Nuclear matter and neutron stars in a parity doublet model

International Nuclear Information System (INIS)

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

230

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

231

Nuclear Matter in Neutron Stars-A Great Challenge in Nuclear Physics—

Lack of our knowledge on the nuclear (hadronic) matter in the neutron star prevents us from understanding its internal structure. The elucidation of the neutron star matter is one of the most important and challenging subjects in nuclear physics today. The nuclear matter EOS (Equation Of State) which would describe pure neutron matter in the outer core of the neutron star is studied via various laboratory experiments particularly by using neutron-rich nuclei. Hyperons and/or kaons are expected to appear in the high density matter in the inner core, which is also experimentally investigated via hypernuclei and kaonic nuclei. Most of the EOS's including hyperons or kaons lead to a serious discrepancy against the large mass ( ˜ 2 M ? ) for the recently observed neutron stars, and resolution of this mystery requires new theoretical frameworks in nuclear physics which correctly describe high density matter, some of which may incorporate hadronic degrees of freedom with a deconfined quark matter phase.

Tamura, Hirokazu

232

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

233

Investigations of instabilities in nuclear matter in stochastic relativistic models

Energy Technology Data Exchange (ETDEWEB)

The spinodal instabilities for symmetric nuclear matter at finite temperature are studied within different relativistic mean-field models in the semi-classical approximation and the relativistic results are compared with Skyrme type non-relativistic calculations. Qualitatively similar results appear in the unstable response of the system in both non-relativistic and relativistic descriptions. Furthermore, the early growth of baryon, scalar and current density correlation functions are calculated for hot symmetric nuclear matter.

Ayik, S., E-mail: ayik@tntech.edu [Physics Department, Tennessee Technological University, Cookeville, TN 38505 (United States); Yilmaz, O.; Acar, F.; Danisman, B. [Physics Department, Middle East Technical University, 06531 Ankara (Turkey); Er, N. [Physics Department, Abant Izzet Baysal University, Bolu (Turkey); Gokalp, A. [Physics Department, Middle East Technical University, 06531 Ankara (Turkey)

2011-06-01

234

Investigations of instabilities in nuclear matter in stochastic relativistic models

International Nuclear Information System (INIS)

The spinodal instabilities for symmetric nuclear matter at finite temperature are studied within different relativistic mean-field models in the semi-classical approximation and the relativistic results are compared with Skyrme type non-relativistic calculations. Qualitatively similar results appear in the unstable response of the system in both non-relativistic and relativistic descriptions. Furthermore, the early growth of baryon, scalar and current density correlation functions are calculated for hot symmetric nuclear matter.

235

Properties of hot nuclear matter with finite effective interaction

International Nuclear Information System (INIS)

The equation of state (EOS) of nuclear matter is the key ingredient in the microscopic theories developed to explain the dynamics of heavy-ion collisions and phase transition phenomena like liquid-gas phase transition and phase transition to quark-gluon plasma (QGP). The purpose of this work is to study the properties of nuclear matter, especially the mean field and phase transition to QGP by using finite range effective interactions

236

Relativistic and non-relativistic studies of nuclear matter

Recently we showed that while the tensor force plays an important role in nuclear matter saturation in non-relativistic studies, it does not do so in relativistic studies. The reason behind this is the role of $M^*$, the sum of nucleon mass and its attractive self-energy in nuclear matter. Yet nonrelativistic calculations at a certain level of approximation are far less difficult than comparative relativistic calculation. Naturally the question arises if one can modify a non...

Banerjee, M. K.; Tjon, J. A.

2001-01-01

237

The role of tensor force in nuclear matter saturation

Using a relativistic Dirac-Brueckner analysis the pion contribution to the ground state energy of nuclear matter is studied. Evidence is presented that the role of the tensor force in the saturation mechanism is substantially reduced compared to its dominant role in a usual non-relativistic treatment. The reduction of the pion contribution in nuclear matter is due to many-body effects present in a relativistic treatment. In particular, we show that the damping of OPEP is act...

Banerjee, Manoj K.; Tjon, John A.

1997-01-01

238

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)

239

Nuclear incompressibility: from finite nuclei to nuclear matter

International Nuclear Information System (INIS)

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

240

Many-body theory of nuclear and neutron star matter

International Nuclear Information System (INIS)

We present results obtained for nuclei, nuclear and neutron star matter, and neutron star structure obtained with the recent Argonne v18 two- nucleon and Urbana IX three-nucleon interactions including relativistic boost corrections. These interactions predict that matter will undergo a transition to a spin layered phase with neutral pion condensation. We also consider the possibility of a transition to quark matter. (orig.)

241

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

242

Effects of Brown-Rho scalings in nuclear matter, neutron stars and finite nuclei

International Nuclear Information System (INIS)

We have carried out calculations for nuclear matter, neutron stars and finite nuclei using NN potentials with and without the medium-dependent modifications based on the Brown-Rho (BR) scalings. Using the Vlow-k low-momentum interactions derived from such potentials, the equations of state (EOS) for symmetric and asymmetric nuclear matter, for densities up to ? 5?0, are calculated using a RPA method where the particle-particle hole-hole ring diagrams are summed to all orders. The medium effects from both a linear BR scaling (BR1) and a non-linear one (BR2) are considered, and they both are essential for our EOSs to reproduce the nuclear matter saturation properties. For densities ? below ?0, results from BR1 and BR2 are close to each other. For higher densities, the EOS given by BR2 is more desirable and is well reproduced by that given by the interaction (Vlow-k+TBF) where Vlow-k is the unsealed low-momentum interaction and TBF is an empirical Skyrme three-body force. The moment of inertia of neutron stars is ? 60 and ? 25Mo-dotkm2 respectively with and without the inclusion of the above BR2 medium effects. Effects from the BR scaling are important for the long half-life, ? 5000yrs, of the 14C - 14N ?-decay.

243

Higher-order symmetry energy of nuclear matter and the inner edge of neutron star crusts

The parabolic approximation to the equation of state of the isospin asymmetric nuclear matter (ANM) is widely used in the literature to make predictions for the nuclear structure and the neutron star properties. Based on the realistic M3Y-Paris and M3Y-Reid nucleon-nucleon interactions, we investigate the effects of the higher-order symmetry energy on the proton fraction in neutron stars and the location of the inner edge of their crusts and their core-crust transition density and pressure, thermodynamically. Analytical expressions for different-order symmetry energy coefficients of ANM are derived using the realistic interactions mentioned above. It is found that the higher-order terms of the symmetry energy coefficients up to its eighth-order (E$_{sym8}$) contributes substantially to the proton fraction in $\\beta$ stable neutron star matter at different nuclear matter densities, the core-crust transition density and pressure. Even by considering the symmetry energy coefficients up to E$_{sym8}$, we obtain a...

Seif, W M

2014-01-01

244

Effective field theory for nuclear matter

We apply the relativistic chiral Lagrangian to the nuclear equation of state. An effective chiral power expansion scheme, which is constructed to work around nuclear saturation density, is presented. The leading and subleading terms are evaluated and are shown to provide an equation of state with excellent saturation properties. Our saturation mechanism is found to probe details of the nuclear pion dynamics.

Lutz, Matthias

1999-01-01

245

Saturation properties of nuclear matter with nonlocal confining solitons

International Nuclear Information System (INIS)

Saturation properties of a quark-based picture of nuclear matter are examined. Soliton matter consisting of nonlocal confining solitons is used to model nuclear matter. Each composite nucleon is described by a non-topological soliton as given by the Global Color Model. Techniques and concepts applied are known from the description of crystal lattices. In particular, the Wigner-Seitz approximation is used to calculate the properties of the soliton lattice at the mean-field level. The saturation density and incompressibility are calculated as function of the single input parameter of the model. (author)

246

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)

247

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)

248

Nuclear and Neutron Matter Calculations with Different Model Spaces

In this work we investigate the so-called model-space Brueckner-Hartree-Fock (MBHF) approach for nuclear matter as well as for neutron matter and the extension of this which includes the particle-particle and hole-hole (PPHH) diagrams. A central ingredient in the model-space approach for nuclear matter is the boundary momentum $k_M$ beyond which the single-particle potential energy is set equal to zero. This is also the boundary of the model space within which the PPHH diagrams are calculated. It has been rather uncertain which value should be used for $k_M$. We have carried out model-space nuclear matter and neutron matter calculations with and without PPHH diagrams for various choices of $k_M$ and using several modern nucleon-nucleon potentials. Our results exhibit a saturation region where the nuclear and neutron matter matter energies are quite stable as $k_M$ varies. The location of this region may serve to determine an "optimum" choice for $k_M$. However, we find that the strength of the tensor force ha...

Engvik, L; Hjorth-Jensen, M; Kuo, T T S

1997-01-01

249

Relativistic Mean-Field Hadronic Models under Nuclear Matter Constraints

Relativistic mean-field (RMF) models have been widely used in the study of many hadronic frameworks because of several important aspects not always present in nonrelativistic models, such as intrinsic Lorentz covariance, automatic inclusion of spin, appropriate saturation mechanism for nuclear matter, causality and, therefore, no problems related to superluminal speed of sound. With the aim of identifying the models which best satisfy well known properties of nuclear matter, we have analyzed 263 parameterizations of seven different types of RMF models under three different sets of constraints related to symmetric nuclear matter, pure neutron matter, symmetry energy, and its derivatives. One of these (SET1) is formed of the same constraints used in a recent work in which we analyzed 240 Skyrme parameterizations. The results pointed to 2 models consistent with all constraints. Using another set of constraints, namely, SET2a, formed by the updated versions of the previous one, we found 4 models approved simultan...

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

2014-01-01

250

Nuclear matter and finite nuclei properties using simple effective interaction

International Nuclear Information System (INIS)

The last three decades have seen a regular interest to explain consistently the properties of nuclear matter, finite nuclei and nuclear reactions (nucleon-nucleus and nucleus-nucleus) with an effective interaction that has the efficiency to describe the two body system accurately. The relativistic and non-relativistic microscopic models, such as, Dirac-Brueckner-Hartree-Fock (DBHF), Brueckner-Hartree-Fock (BHF) and calculations using realistic interaction are considered to be standard techniques for reference in the regime of nuclear matter (NM), but ab initio extension to finite nucleus calculation in these models is still in rudimentary stage

251

Nuclear symmetry energy from effective interaction and masses of isospin asymmetric nuclei

Energy Technology Data Exchange (ETDEWEB)

Binding energy of isospin asymmetric nuclei can be accessed with minimally modified formula along the lines of the liquid droplet model by partitioning the symmetry term into volume and surface terms. The volume symmetry energy coefficient extracted from finite nuclei provides a constraint on the nuclear symmetry energy. This approach also yields the neutron skin of a finite nucleus through its relationship with the volume and surface symmetry terms and the Coulomb energy coefficient. The symmetry energy at saturation density obtained from the isoscalar as well as isovector components of the density dependent M3Y effective interaction is found to be in close agreement with the volume symmetry energy coefficient extracted from the measured atomic masses.

Mukhopadhyay, Tapan [Variable Energy Cyclotron Centre, 1/AF Bidhan Nagar, Kolkata 700 064 (India)]. E-mail: tkm@veccal.ernet.in; Basu, D.N. [Variable Energy Cyclotron Centre, 1/AF Bidhan Nagar, Kolkata 700 064 (India)]. E-mail: dnb@veccal.ernet.in

2007-06-01

252

Isospin Violating Dark Matter Search by Nuclear Emulsion Detector

Dark matter signal and its annual modulation of event number are observed by some direct searches in small mass region. However, the regions have been excluded by others. The isospin-violating dark matter is a hopeful candidate to explain the discrepancy. We study the possibility that a future project of dark matter search using nuclear emulsion can reach favored region by the isospin-violating dark matter. Since the detector has the directional sensitivity, it is expected to examine the region including the modulation property.

Nagao, Keiko I

2012-01-01

253

From nuclear matter to finite nuclei. Pt. 1

International Nuclear Information System (INIS)

In this paper we develop various parametrizations of the nuclear matter Dirac-Brueckner G-matrix, which are suitable for application in relativistic Hartree-Fock calculations of finite nuclei. The relativistic one boson exchange model forms the basis of this effective interaction. The parameters, which are obtained from a least squares fit, explicitly depend on the density. We also require the interaction to reproduce the self-energies and the binding energy of nuclear matter very accurately. It is shown that for densities up to 1.5 times normal nuclear density the saturation curve virtually coincides with the original Dirac-Brueckner result and yields a good prediction of the nuclear matter compressibility. (orig.)

254

Nuclear physics: the core of matter, the fuel of stars

International Nuclear Information System (INIS)

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

255

? meson mass and decay width in nuclear matter

The ? meson spectrum, which in vacuum is dominated by its coupling to the K¯K system, is modified in nuclear matter. Following a model based on chiral SU(3) dynamics we calculate the ? meson self-energy in nuclear matter considering the K and K¯ in-medium properties. For the latter we use the results of previous calculations which account for S- and P-wave kaon-nucleon interactions based on the lowest order meson-baryon chiral effective Lagrangian, and this leads to a dressing of the kaon propagators in the medium. In addition, a set of vertex corrections is evaluated to fulfill gauge invariance, which involves contact couplings of the ? meson to S-wave and P-wave kaon-baryon vertices. Within this scheme the mass shift and decay width of the ? meson in nuclear matter are studied.

Cabrera, D.; Vicente Vacas, M. J.

2003-04-01

256

? meson mass and decay width in nuclear matter

International Nuclear Information System (INIS)

The ? meson spectrum, which in vacuum is dominated by its coupling to the K-barK system, is modified in nuclear matter. Following a model based on chiral SU(3) dynamics we calculate the ? meson self-energy in nuclear matter considering the K and K-bar in-medium properties. For the latter we use the results of previous calculations which account for S- and P-wave kaon-nucleon interactions based on the lowest order meson-baryon chiral effective Lagrangian, and this leads to a dressing of the kaon propagators in the medium. In addition, a set of vertex corrections is evaluated to fulfill gauge invariance, which involves contact couplings of the ? meson to S-wave and P-wave kaon-baryon vertices. Within this scheme the mass shift and decay width of the ? meson in nuclear matter are studied

257

Charm and Hidden Charm Scalar Resonances in Nuclear Matter

We study the properties of the scalar charm resonances $D_{s0}(2317)$ and $D_0(2400)$, and the theoretical hidden charm state X(3700) in nuclear matter. We find that for the $D_{s0}(2317)$ and X(3700) resonances, with negligible and small width at zero density, respectively, the width becomes about $100 {\\rm MeV}$ and $200 {\\rm MeV}$ at normal nuclear matter density, accordingly. For $D_0(2400)$ the change in width is relatively less important. We discuss the origin of this new width and trace it to reactions occurring in the nucleus. We also propose a possible experimental test for those modifications in nuclear matter, which will bring valuable information on the nature of those scalar resonances and the interaction of $D$ mesons with nucleons.

Tolos, Laura; Gamermann, Daniel; Oset, Eulogio

2009-01-01

258

Pion absorption in excited nuclear matter

International Nuclear Information System (INIS)

The target dependence and azimuthal correlations of protons and plons are investigated for pA reactions at 4.9, 60 and 200 GeV. The experimental observations can be understood qualitatively under the assumption that pions are absorbed in excited target spectator matter. (orig.)

259

On growth of spinodal instabilities in nuclear matter

Early growth of density fluctuations of nuclear matter in spinodal region is investigated employing the stochastic mean-field approach. In contrast to the earlier treatments in which only collective modes were included in the calculations, in the present work non-collective modes are also included, thus providing a complete treatment of the density correlation functions. Calculations are carried out for symmetric matter in non-relativistic framework using a semi-classical approximation.

Yilmaz, O; Acar, F; Gokalp, A

2015-01-01

260

Relativistic Structure of the Nucleon Self-Energy in Asymmetric Nuclei

The Dirac structure of the nucleon self-energy in asymmetric nuclear matter cannot reliably be deduced from the momentum dependence of the single-particle energies. It is demonstrated that such attempts yield an isospin dependence with even a wrong sign. Relativistic studies of finite nuclei have been based on such studies of asymmetric nuclear matter. The effects of these isospin components on the results for finite nuclei are investigated.

Ulrych, S.; Mu?ther, H.

1997-01-01

261

Role of the tensor force in nuclear matter saturation

International Nuclear Information System (INIS)

In the framework of a relativistic Dirac-Brueckner analysis the pion contribution to the ground state energy of nuclear matter is studied using pseudovector coupling. Evidence is presented that the role of the tensor force in the saturation mechanism is substantially reduced compared to its dominant role in a usual nonrelativistic treatment. The reduction of the pion contribution in nuclear matter is due to many-body effects present in a relativistic treatment. In particular, we show that the damping of the one-pion-exchange potential is actually due to the decrease of M*/M with increasing density. copyright 1998 The American Physical Society

262

The role of tensor force in nuclear matter saturation

Using a relativistic Dirac-Brueckner analysis the pion contribution to the ground state energy of nuclear matter is studied. Evidence is presented that the role of the tensor force in the saturation mechanism is substantially reduced compared to its dominant role in a usual non-relativistic treatment. The reduction of the pion contribution in nuclear matter is due to many-body effects present in a relativistic treatment. In particular, we show that the damping of OPEP is actually due to the decrease of $M^*/M$ with increasing density.

Banerjee, M K; Banerjee, Manoj K.; Tjon, John A.

1998-01-01

263

Lectures notes on phase transformations in nuclear matter

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

López, Jorge A

2000-01-01

264

From light nuclei to nuclear matter the role of relativity?

Energy Technology Data Exchange (ETDEWEB)

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

Coester, F.; Physics

2003-11-10

265

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

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

Coester, F

2003-01-01

266

Towards Nuclear Physics of OHe Dark Matter

The nonbaryonic dark matter of the Universe can consist of new stable charged particles, bound in heavy "atoms" by ordinary Coulomb interaction. If stable particles $O^{--}$ with charge -2 are in excess over their antiparticles (with charge +2), the primordial helium, formed in Big Bang Nucleosynthesis, captures all $O^{--}$ in neutral "atoms" of O-helium (OHe). Interaction with nuclei plays crucial role in the cosmological evolution of OHe and in the effects of these dark a...

Khlopov, Maxim Yu; Mayorov, Andrey G.; Soldatov, Evgeny Yu

2011-01-01

267

Continued fraction approximation for the nuclear matter response function

We use a continued fraction approximation to calculate the RPA response function of nuclear matter. The convergence of the approximation is assessed by comparing with the numerically exact response function obtained with a typical effective finite-range interaction used in nuclear physics. It is shown that just the first order term of the expansion can give reliable results at densities up to the saturation density value.

Margueron, Je?ro?me; Navarro, J.; Giai, Nguyen; Schuck, P.

2008-01-01

268

Nuclear fusion in dense matter: Reaction rate and carbon burning

In this paper we analyze the nuclear fusion rate between equal nuclei for all five different nuclear burning regimes in dense matter (two thermonuclear regimes, two pycnonuclear ones, and the intermediate regime). The rate is determined by Coulomb barrier penetration in dense environments and by the astrophysical S-factor at low energies. We evaluate previous studies of the Coulomb barrier problem and propose a simple phenomenological formula for the reaction rate which cove...

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

2005-01-01

269

Ordered bicontinuous double-diamond morphology in subsaturation nuclear matter

We propose to identify the new "intermediate" morphology in subsaturation nuclear matter observed in a recent quantum molecular dynamics simulation with the ordered bicontinuous double-diamond structure known in block copolymers. We estimate its energy density by incorporating the normalized area-volume relation given in a literature into the nuclear liquid drop model. The resulting energy density is higher than the other five known morphologies.

Matsuzaki, M

2006-01-01

270

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

271

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.

2011-04-01

272

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

273

Nuclear condensation and symmetry energy of dilute nuclear matter: an S-matrix approach

Based on the general analysis of the grand canonical partition function in the S-matrix framework, the calculated results on symmetry energy, free energy and entropy of dilute warm nuclear matter are presented. At a given temperature and density, the symmetry energy or symmetry free energy of the clusterized nuclear matter in the S-matrix formulation deviates, particularly at low temperature and relatively higher density, in a subtle way, from the linear dependence on the sq...

De, J. N.; Samaddar, S. K.

2008-01-01

274

Nuclear "pasta" structures in low-density nuclear matter and neutron star crust

In neutron star crust, non-uniform structure of nuclear matter is expected, which is called the "pasta" structure. From the recent studies of giant flares in magnetars, these structures might be related to some observables and physical quantities of the neutron star crust. To investigate the above quantities, we numerically explore the pasta structures with a fully threedimensional geometry and study the properties of low-density nuclear matter, based on the relativistic mea...

Okamoto, Minoru; Maruyama, Toshiki; Yabana, Kazuhiro; Tatsumi, Toshitaka

2013-01-01

275

International Nuclear Information System (INIS)

The properties of nuclear matter and nuclear scattering reactions were studied from the same effective nucleon-nucleon interactions. In this project, we used CDM3Y and M3Y-Pn interaction version as the input to build the nuclear interaction potential (nuclear optical potential). After that, nuclear scattering reactions were studied by coupled channel formalism and folding model for scattering potential. The theoretical calculated cross sections of (alpha, nucleus) and (nucleon, nucleus) scattering system have been compared with the experimental values. Using the above interactions, the properties of nuclear matter: (i) biding energy, (ii) pressure and (iii) Compressibility were deduced in the Hartree-Fock calculation frame work. From the consistence between theory and experiment, the information of nuclear structure has been extracted. (author)

276

Inequalities for low-energy symmetric nuclear matter

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

Lee, Dean

2004-01-01

277

4. Chemistry of nuclear radiation interaction with matter

International Nuclear Information System (INIS)

The properties are explained of nuclear radiation, its passage through and absorption by matter and luminescent, photographic, colorimetric and chemical ionizing radiation effects. The concept is discussed of radiation chemistry and its methods, as are chemical dosimetry instrumentation and methods. (M.D.)

278

Phase transitions of nuclear matter beyond mean field theory

International Nuclear Information System (INIS)

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

279

Low density clustering effects of Skyrme interactions in nuclear matter

International Nuclear Information System (INIS)

An orthonormal set of single-nucleon orbital functions, explicitly satisfying the Hartree-Fock equations for occupied states, is introduced and shown to display, assuming several parameterizations of the Skyrme interaction, alpha-clustering effects at low densities in nuclear matter

280

Thermostatic properties of semi-infinite symmetric nuclear matter

International Nuclear Information System (INIS)

The thermal evolution of surface thickness and surface free energy of semi-infinite symmetric nuclear matter have been computed using a hot Thomas-Fermi model. Performing a leptodermous expansion of the total free energy, approximated analytical formulas for these quantities have been obtained. (orig.)

281

Modifications of scalar and vector mesons in nuclear matter

International Nuclear Information System (INIS)

Starting from the realistic dynamical model for the ?? interaction recently developped by the Juelich group, we study the modifications of the scalar-isoscalar and vector-isovector mesons occuring as resonances in 2? scattering in nuclear matter due to charges of the pion dispersion relation. (orig.)

282

Three dimensional structure of low-density nuclear matter

We numerically explore the pasta structures and properties of low-density nuclear matter without any assumption on the geometry. We observe conventional pasta structures, while a mixture of the pasta structures appears as a metastable state at some transient densities. We also discuss the lattice structure of droplets.

Okamoto, Minoru; Yabana, Kazuhiro; Tatsumi, Toshitaka

2011-01-01

283

Three-dimensional calculation of inhomogeneous nuclear matter

Energy Technology Data Exchange (ETDEWEB)

We numerically explore the pasta structures and properties of low-density symmetric nuclear matter without any assumption on the geometry. We observe conventional pasta structures, while a mixture of the pasta appears as a meta-stable state at some transient densities. We also analyze the lattice structure of droplets.

Okamoto, Minoru; Maruyama, Toshiki; Yabana, Kazuhiro; Tatsumi, Toshitaka [Graduate School of Pure and Applied Science, University of Tsukuba (Japan); Advanced Science Research Center, Japan Atomic Energy Agency (Japan); Graduate School of Pure and Applied Science, University of Tsukuba (Japan); Department of Physics, Kyoto University (Japan)

2012-11-12

284

Three-dimensional structure of low-density nuclear matter

Energy Technology Data Exchange (ETDEWEB)

We numerically explore the pasta structures and properties of low-density nuclear matter without any assumption on the geometry. We observe conventional pasta structures, while a mixture of the pasta structures appears as a metastable state at some transient densities. We also discuss the lattice structure of droplets.

Okamoto, Minoru, E-mail: okamoto@nucl.ph.tsukuba.ac.jp [Graduate School of Pure and Applied Science, University of Tsukuba, Tennoudai 1-1-1, Tsukuba, Ibaraki 305-8571 (Japan); Advanced Science Research Center, Japan Atomic Energy Agency, Shirakata Shirane 2-4, Tokai, Ibaraki 319-1195 (Japan); Maruyama, Toshiki, E-mail: maruyama.toshiki@jaea.go.jp [Advanced Science Research Center, Japan Atomic Energy Agency, Shirakata Shirane 2-4, Tokai, Ibaraki 319-1195 (Japan); Graduate School of Pure and Applied Science, University of Tsukuba, Tennoudai 1-1-1, Tsukuba, Ibaraki 305-8571 (Japan); Yabana, Kazuhiro, E-mail: yabana@nucl.ph.tsukuba.ac.jp [Graduate School of Pure and Applied Science, University of Tsukuba, Tennoudai 1-1-1, Tsukuba, Ibaraki 305-8571 (Japan); Center of Computational Sciences, University of Tsukuba, Tennoudai 1-1-1, Tsukuba, Ibaraki 305-8571 (Japan); Tatsumi, Toshitaka, E-mail: tatsumi@ruby.scphys.kyoto-u.ac.jp [Department of Physics, Kyoto University, Kyoto 606-8502 (Japan)

2012-07-09

285

Medium modifications of baryon properties in nuclear matter and hypernuclei

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

286

Medium modifications of baryon properties in nuclear matter and hypernuclei

We study the medium modifications of baryon properties in nuclear many-body systems, especially in ? hypernuclei. The nucleon and the ? 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 ? hypernuclei. The present model predicts a significant increase of the baryon radius in nuclear medium.

Liang, J. S.; Shen, H.

2013-09-01

287

Nuclear matter from effective quark-quark interaction

We study neutron matter and symmetric nuclear matter with the quark-meson model for the two-nucleon interaction. The Bethe-Bruckner-Goldstone many-body theory is used to describe the correlations up to the three hole-line approximation with no extra parameters. At variance with other non-relativistic realistic interactions, the three hole-line contribution turns out to be non-negligible and to have a substantial saturation effect. The saturation point of nuclear matter, the compressibility, the symmetry energy and its slope are within the phenomenological constraints. Since the interaction also reproduces fairly well the properties of three nucleons system, these results indicate that the explicit introduction of the quark degrees of freedom for the construction of the nucleon-nucleon interaction strongly reduces the possible role of three-body forces

Baldo, M

2014-01-01

288

Relativistic Mean-Field Models and Nuclear Matter Constraints

This work presents a preliminary study of 147 relativistic mean-field (RMF) hadronic models used in the literature, regarding their behavior in the nuclear matter regime. We analyze here different kinds of such models, namely: (i) linear models, (ii) nonlinear \\sigma^3+\\sigma^4 models, (iii) \\sigma^3+\\sigma^4+\\omega^4 models, (iv) models containing mixing terms in the fields \\sigma and \\omega, (v) density dependent models, and (vi) point-coupling ones. In the finite range models, the attractive (repulsive) interaction is described in the Lagrangian density by the \\sigma (\\omega) field. The isospin dependence of the interaction is modeled by the \\rho meson field. We submit these sets of RMF models to eleven macroscopic (experimental and empirical) constraints, used in a recent study in which 240 Skyrme parametrizations were analyzed. Such constraints cover a wide range of properties related to symmetric nuclear matter (SNM), pure neutron matter (PNM), and both SNM and PNM.

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

2013-01-01

289

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

290

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

291

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

International Nuclear Information System (INIS)

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

292

A Phase-Space Noncommutative Picture of Nuclear Matter

Noncommutative features are introduced into a relativistic quantum field theory model of nuclear matter, the quantum hadrodynamics-I nuclear model (QHD-I). It is shown that the nuclear matter equation of state (NMEoS) depends on the fundamental momentum scale, $\\eta$, introduced by the phase-space noncommutativity (NC). Although it is found that NC geometry does not affect the nucleon fields up to $O(\\eta^2)$, it affects the energy density, the pressure and other derivable quantities of the NMEoS, such as the nucleon \\textit{effective mass}. Under the conditions of saturation of the symmetric NM, the estimated value for the noncommutative parameter is $\\sqrt{\\eta}=0.014 MeV/c$.

Bertolami, Orfeu

2015-01-01

293

Nuclear "pasta" structures in low-density nuclear matter and neutron star crust

In neutron star crust, non-uniform structure of nuclear matter is expected, which is called the "pasta" structure. From the recent studies of giant flares in magnetars, these structures might be related to some observables and physical quantities of the neutron star crust. To investigate the above quantities, we numerically explore the pasta structures with a fully threedimensional geometry and study the properties of low-density nuclear matter, based on the relativistic mean-field model and the Thomas-Fermi approximation. We observe typical pasta structures for fixed proton number-fraction and two of them for cold catalyzed matter. We also discuss the crystalline configuration of "pasta".

Okamoto, Minoru; Yabana, Kazuhiro; Tatsumi, Toshitaka

2013-01-01

294

Computational methods for the nuclear and neutron matter problems. Technical progress report

International Nuclear Information System (INIS)

Progress is reported under the following headings: mirror potential methods (approximate methods, non-local mirror potentials, and four nucleon calculations); quark clustering and nuclear matter; realistic variational calculations of nuclei; and nuclear matter variational studies

295

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

296

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

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

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

2004-01-01

297

Statistic properties of 'hot' nuclei and liquid-gas phase transition in nuclear matter

International Nuclear Information System (INIS)

The temperature dependence of thermodynamical functions, such as excitation energies, entropies etc. of both nuclear matter and finite nuclei are discussed in a finite temperature extended Thomas-Fermi approach. Equation of state in nuclear matter at finite temperature is presented, the critical temperature of liquid-gas phase transition and its dependence on asymmetry of nuclear matter are calculated

298

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

299

Review of the theory of infinite nuclear matter

International Nuclear Information System (INIS)

Given a two-body force, there seems to be two distinct starting points in the many-body perturbation-theoretic problem of computing the energy per nucleon of infinite (as well as finite) nuclear matter: ordinary Hartree-Fock theory and the Brueckner theory. The former theory, treated almost exclusively with plane-wave solutions, has long-ago fallen into disuse, to yield to the latter, apparently more sophisticated, theory. After a brief outline of many-fermion diagramatic techniques, the Brueckner-Bethe-Goldstone series expansion in terms of the density is discussed as a low density, non-ideal Fermi gas theory, whose convergence is analyzed. A calculation based on particle-hole Green's function techniques shows that a nucleon gas condenses to the liquid phase at about 3% of the empirical nuclear matter saturation density. The analogy between the BBG expansion and the virial expansion for a classical or quantum gas is studied with special emphasis on the apparent impossibility of analytical-continuing the latter gas theory to densities in the liquid regime, as first elucidated by Lee and Yang. It is finally argued that ordinary HF theory may provide a good starting point for the eventual understanding of nuclear matter as it gives (in the finite nuclear problem, at any rate) not only the basic liquid properties of a definite density and a surface but also provides independent-particle aspects, avoiding at the same time the idea of n-body clusters appropriate only for d of n-body clusters appropriate only for dilute gases. This program has to date not been carried out for infinite nuclear matter, mainly because of insufficient knowledge regarding low-energy, non-plane-wave solutions of the HF equations, in the thermodynamic limit

300

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

301

Appearance of the Gyroid Network Phase in Nuclear Pasta Matter

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

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

2014-01-01

302

Properties of nucleon in nuclear matter: once more

Energy Technology Data Exchange (ETDEWEB)

We calculate the mass and residue of the nucleon in nuclear matter in the frame work of QCD sum rules using the nucleon's interpolating current with an arbitrary mixing parameter. We evaluate the effects of the nuclear medium on these quantities and compare the results obtained with the existing theoretical predictions. The results are also compared with those obtained in vacuum to find the shifts in the quantities under consideration. Our calculations show that these shifts in the mass and residue are about 32 and 15%, respectively. (orig.)

Azizi, K. [Dogus University, Department of Physics, Istanbul (Turkey); Er, N. [Abant Izzet Baysal University, Department of Physics, Bolu (Turkey)

2014-05-15

303

Hadron parameters and nuclear matter equation of state

International Nuclear Information System (INIS)

It has been possible, recently, to understand the saturation density and binding energy of symmetric nuclear matter equation of state (EOS) taking two body interaction alone in relativistic as well as non-relativistic approaches, including in-medium modification of hadron parameters due to restoration of chiral symmetry. In the studies, Bonn potential, in which the meson degrees of freedom are treated explicitly, was taken for two body interaction and modification of hadron parameters inside nuclear medium was taken according to Brown-Rho (BR) scaling. Thus, to understand different results obtained in relativistic and non-relativistic approaches one need to understand the sensitivity of EOS on different hadronic parameters

304

Properties of nucleon in nuclear matter: once more

International Nuclear Information System (INIS)

We calculate the mass and residue of the nucleon in nuclear matter in the frame work of QCD sum rules using the nucleon's interpolating current with an arbitrary mixing parameter. We evaluate the effects of the nuclear medium on these quantities and compare the results obtained with the existing theoretical predictions. The results are also compared with those obtained in vacuum to find the shifts in the quantities under consideration. Our calculations show that these shifts in the mass and residue are about 32 and 15%, respectively. (orig.)

305

The decay of the ?-resonance in nuclear matter

International Nuclear Information System (INIS)

The ?-resonance is believed to play an important role in the dynamics of a nucleus-nucleus collision at intermediate energies, as well as for the emission of energetic particles. In some tests using hadronic probes as well as in some electromagnetic processes, a rather large increase in width and in some cases a shift in peak energy have been observed. For making detailed considerations of such phenomena, it is necessary to understand the properties of the resonance in the nuclear medium. In this paper we will present some results of calculations of the ?-width in nuclear matter. (author)

306

Three-body properties in hot and dense nuclear matter

We derive three-body equations valid at finite densities and temperatures. These are based on the cluster mean field approach consistently including proper self energy corrections and the Pauli blocking. As an application we investigate the binding energies of triton and determine the Mott densities and momenta relevant for a many particle description of nuclear matter in a generalized Beth-Uhlenbeck approach. The method, however is not restricted to nuclear physics problems but may also be relevant, e.g., to treat three-particle correlations in weekly doped semiconducters or strongly coupled dense plasmas.

Beyer, M; Kuhrts, C; Röpke, G

1999-01-01

307

Variational calculations of models of nuclear and neutron matter

International Nuclear Information System (INIS)

The authors report results of variational calculations of models of nuclear matter in which the nuclear interaction is approximated by a sum of central, spin, isospin and tensor forces. The models are based on realistic potentials such as those of Reid, Bethe-Johnson, Hamada-Johnston, and Gammel-Thaler. The correlation operator in the variational wave function contains central, spin, isospin and tensor terms. The authors briefly review the Fermi-hypernetted-chain, and single-operator-chain (SOC) methods used to calculate the energy expectation value. The energies obtained for these simple models by various variational and reaction matrix calculations seem to be in reasonable agreement. Results with the SOC approximation for the ?3 model of neutron matter, in which the interaction has only central and spin components, are also reported. These are in good agreement with the energies obtained by summing multiple operator chains. (Auth.)

308

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.)

309

Strangeness in nuclear matter at DA?NE

International Nuclear Information System (INIS)

The low energy kaons from the ? meson produced at DA?NE offer a unique opportunity to study strangeness in nuclear matter. The interaction of kaons with hadronic matter can be investigated at DA?NE using three main approaches: study of hypernuclei production and decay, kaons scattering on nucleons, kaonic atoms formation. These studies explore kaon-nucleon and hyperon-nucleon forces at very low energy, the nuclear shell model in presence of strangeness quantum number and eventual quarks deconfinement phenomena. The experiments devoted to study this physical program at DA?NE are FINUDA and DEAR. The physics topics of both experiments are illustrated together with a detailed descriptions of the two detectors

310

Pure Neutron Matter Constraints and Nuclear Symmetry Energy

International Nuclear Information System (INIS)

In this review, we will discuss the results of our recent work [1] to study the general optimization of the pure isovector parameters of the popular relativistic mean-field (RMF) and Skyrme-Hartree-Fock (SHF) nuclear energy-density functionals (EDFs), using constraints on the pure neutron matter (PNM) equation of state (EoS) from recent ab initio calculations. By using RMF and SHF parameterizations that give equivalent predictions for ground-state properties of doubly magic nuclei and properties of symmetric nuclear matter (SNM) and PNM, we found that such optimization leads to broadly consistent symmetry energy J and its slope parameter L at saturation density within a tight range of ?(J) sym, (b) the symmetry energy at supra-saturation densities, and (c) the radius of neutron stars.

311

Relativistic nuclear matter with alternative derivative coupling models

International Nuclear Information System (INIS)

Effective Lagrangians involving nucleons coupled to scalar and vector fields are investigated within the framework of relativistic mean-field theory. The study presents the traditional Walecka model and different kinds of scalar derivative couplings suggested by Zimanyi and Moszkowski. The incompressibility (presented in an analytical form), scalar potential, and vector potential at the saturation point of nuclear matter are compared for these models. The real optical potential for the models are calculated and one of the models fits well the experimental curve from -50 to 400 MeV while also giving a soft equation of state. By varying the coupling constants and keeping the saturation point of nuclear matter approximately fixed, only the Walecka model presents a first order phase transition for finite temperature at zero density

312

Finite size effects in Neutron Star and Nuclear matter simulations

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

Molinelli, P A Giménez

2014-01-01

313

Localized control of light–matter interactions by using nanoscale asymmetric TiO2

International Nuclear Information System (INIS)

This paper reports an asymmetry structure-mediated route for highly localized control of light–matter interactions by using tapered TiO2. We demonstrate for the first time that the growth habit of Ag nanostructures on tapered TiO2 can be tuned by controllable photolysis. Site-selective anchoring of Ag nanoparticles or nanowires on tapered TiO2 can be achieved by simply changing the external light. We further show that the obtained tapered TiO2–Ag hetero-nanostructures present excellent light-trapping ability over a wide range of wavelengths which is considered to originate from the unique synergistic effects of graded waveguiding and plasmonic light trapping. This improved photon-management capability renders the prepared substrate a very promising candidate for optical sensing application. For this purpose, an enhanced sensitivity for trace detection is confirmed. These findings open up promising avenues for tailoring of light–matter interactions which are of special interest for studying controllable photolysis activation processes and diverse applications such as nanostructure growth, trace detection, photocatalysis and solar cells. (paper)

314

Detector developing for directional dark matter search with nuclear emulsion

We are planing the directional dark matter search experiment with nuclear emulsion. Recoiled atoms inside of the emulsion fly several hundred nm, and it is too short to detect with usual emulsion. Fine crystal emulsion was needed to detect such tracks. We developed new method to produce them and succeeded to make crystals small as 20 nm at the minimum size. We also study several methods to improve sensitivity and reduce background noise to survey very interesting cross section region.

Asada, T.; Naka, T.; Kuwabara, K.; Katsuragawa, T.; Yoshimoto, M.; Hakamata, K.; Ishikawa, M.; Nakamura, M.; Sato, O.; Nakano, T.

2013-12-01

315

Self-Energy of Decuplet Baryons in Nuclear Matter

We calculate, in chiral perturbation theory, the change in the self-energy of decuplet baryons in nuclear matter. These self-energy shifts are relevant in studies of meson-nucleus scattering and of neutron stars. Our results are leading order in an expansion in powers of the ratio of characteristic momenta to the chiral symmetry-breaking scale (or the nucleon mass). Included are contact diagrams generated by 4-baryon operators, which were neglected in earlier studies for the...

Ouellette, Stephen M.; Seki, Ryoichi

1997-01-01

316

Compression modulus of finite nuclear matter at zero temperature

International Nuclear Information System (INIS)

By taking account of the finite-size effect rationally in the framework of the Hartree Fock theory, the compression modulus KA at zero temperature of finite nuclear matter is evaluated with the Skyrme force SKM. Energies of the isoscalar giant monopole resonance of nuclei calculated are found to be in agreement with the experimental and empirical values. The influence of neutron-proton asymmetry, finite size and Coulomb force effects on KA is also investigated

317

Spin instabilities of infinite nuclear matter and effective tensor interactions

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...

Navarro, J.; Polls, A.

2013-01-01

318

Pairing effects in low density domain of nuclear matter

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

Isayev, A A; Yang, J

2004-01-01

319

Pairing effects in low density domain of nuclear matter

Energy Technology Data Exchange (ETDEWEB)

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

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

2004-04-05

320

Pairing effects in low density domain of nuclear matter

International Nuclear Information System (INIS)

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

321

Pairing correlation in nuclear matter from Skyrme force

The properties of pairing correlation in nuclear matter are investigated by using various versions of Skyrme forces. Truncation of states involving pairing correlation, necessary due to zero range nature of the Skyrme force, is discussed in detail. A plateau appears in pairing gap versus cutoff for each force. We propose to choose the cutoff parameter in the middle of the plateau so that the parameterization is independent of nuclides.

Takahara, S.; Onishi, N.; Tajima, N.

1994-01-01

322

Properties of the ? meson in dense nuclear matter

International Nuclear Information System (INIS)

In order to reach a description of the ? meson, which is in accordance with the principles of the gauge invariance of the electromagnetic interaction, the vector-dominance hypothesis, and the unitarity a model for the ? meson in the vacuum is developed. Thereafter follows the calculation of the properties of the ? meson in nuclear matter. First the connection between the spectral function of the ? meson and the dilepton production rate for an equilibrium state is derived. Then the model for the pion in nuclear matter is described. Following approximations are applied: The description of the pion-baryon interaction pursues non-relativistically and both the width of the delta resonance and the short-range repulsive delta-nucleon interaction is neglected. The self-energy of the ? meson in nuclear matter following from this description is formally derived from the requirement to couple the ? meson to a conserved current. The corrections for the 3-point and 4-point vertex resulting from this are calculated and discussed. Thereafter the physical consequences of the changed self-energy of the ? meson in nuclear matter are considered. By means of the spectral function it is shown that up to the two-fold of the ground-state density the position of the resonance is nearly not changed. At still higher densities the resonances is a little shifted to higher energies. In the range of an invariant mass of about 400 meV a strong increasement concentrated on a small range results. This is caused by coupling to a naked delta-hole state and a pion. Finally the possibilities are discussed to apply the results of this thesis to the prediction of experimental data. Thereby it is proved to be necessary to base on a simulation of the heavy ion reaction. (orig./HSI)

323

Investigation of the organic matter in inactive nuclear tank liquids

Energy Technology Data Exchange (ETDEWEB)

Environmental Protection Agency (EPA) methodology for regulatory organics fails to account for the organic matter that is suggested by total organic carbon (TOC) analysis in the Oak Ridge National Laboratory (ORNL) inactive nuclear waste-tank liquids and sludges. Identification and measurement of the total organics are needed to select appropriate waste treatment technologies. An initial investigation was made of the nature of the organics in several waste-tank liquids. This report details the analysis of ORNL wastes.

Schenley, R.L.; Griest, W.H.

1990-08-01

324

Investigation of the organic matter in inactive nuclear tank liquids

International Nuclear Information System (INIS)

Environmental Protection Agency (EPA) methodology for regulatory organics fails to account for the organic matter that is suggested by total organic carbon (TOC) analysis in the Oak Ridge National Laboratory (ORNL) inactive nuclear waste-tank liquids and sludges. Identification and measurement of the total organics are needed to select appropriate waste treatment technologies. An initial investigation was made of the nature of the organics in several waste-tank liquids. This report details the analysis of ORNL wastes

325

Saturated symmetric nuclear matter in strong magnetic fields

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

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

2013-06-01

326

Nuclear fusion in dense matter: Reaction rate and carbon burning

International Nuclear Information System (INIS)

In this paper we analyze the nuclear fusion rates among equal nuclei for all five different nuclear burning regimes in dense matter (two thermonuclear regimes, two pycnonuclear ones, and the intermediate regime). The rate is determined by Coulomb barrier penetration in dense environments and by the astrophysical S factor at low energies. We evaluate previous studies of the Coulomb barrier problem and propose a simple phenomenological formula for the reaction rate that covers all cases. The parameters of this formula can be varied to take into account current theoretical uncertainties in the reaction rate. The results are illustrated for the example of the 12C+12C fusion reaction. This reaction is important for the understanding of nuclear burning in evolved stars, in exploding white dwarfs producing type Ia supernovas, and in accreting neutron stars. The S factor at stellar energies depends on a reliable fit and extrapolation of the experimental data. We calculate the energy dependence of the S factor by using a recently developed parameter-free model for the nuclear interaction, taking into account the effects of the Pauli nonlocality. For illustration, we analyze the efficiency of carbon burning in a wide range of densities and temperatures of stellar matter with the emphasis on carbon ignition at densities ? > or approx. 109 g cm-3

327

Open-charm systems in cold nuclear matter

International Nuclear Information System (INIS)

We study the spectral distributions of charmed meson with JP=0- quantum numbers in cold nuclear matter applying a self-consistent and covariant many-body approach established previously for the nuclear dynamics of kaons. At leading orders the computation requires as input the free-space two-body scattering amplitudes only. Our results are based on the s-wave meson-nucleon amplitudes obtained recently in terms of a coupled-channel approach. The amplitudes are characterized by the presence of many resonances in part so far not observed. This gives rise to an intriguing dynamics of charmed mesons in nuclear matter. At nuclear saturation density we predict a pronounced two-mode structure of the D+ mesons with a main branch pushed up by about 32 MeV. The lower branch reflects the coupling to two resonance-hole states that are almost degenerate. For the D- we obtain a single mode pushed up by about 18 MeV relative to the vacuum mode. Most spectacular are the results for the Ds+ meson. The presence of an exotic resonance-hole state gives rise to a rather broad and strongly momentum dependent spectral distribution

328

Finite size effects in neutron star and nuclear matter simulations

In this work we study molecular dynamics simulations of symmetric nuclear and neutron star matter using a semi-classical nucleon interaction model. Our aim is to gain insight on the nature of the so-called 'finite size effects', unavoidable in this kind of simulations, and to understand what they actually affect. To do so, we explore different geometries for the periodic boundary conditions imposed on the simulation cell: cube, hexagonal prism and truncated octahedron. For nuclear matter simulations we show that, at sub-saturation densities and low temperatures, the solutions are non-homogeneous structures reminiscent of the 'nuclear pasta' phases expected in neutron star matter simulations, but only one structure per cell and shaped by specific artificial aspects of the simulations-for the same physical conditions (i.e. number density and temperature) different cells yield different solutions. The particular shape of the solution at low enough temperature and a given density can be predicted analytically by surface minimization. We also show that even if this behavior is due to the imposition of periodic boundary conditions on finite systems, this does not mean that it vanishes for very large systems, and it is actually independent of the system size. We conclude that, for nuclear matter simulations, the cells' size sets the only characteristic length scale for the inhomogeneities, and the geometry of the periodic cell determines the shape of those inhomogeneities. To model neutron star matter we add a screened Coulomb interaction between protons, and perform simulations in the three cell geometries. Our simulations indeed produce the well known nuclear pasta, with (in most cases) several structures per cell. However, we find that for systems not too large results are affected by finite size in different ways depending on the geometry of the cell. In particular, at the same certain physical conditions and system size, the hexagonal prism yields a single structure per cell while the cubic and truncated octahedron show consistent results, with more than one structure per cell. For systems of the size studied in this work these effects are still noticeable, but we find evidence to support that the dependence of the results on the cell geometry becomes smaller as the system size is increased. When the Coulomb interaction is present, the competition between opposing interactions of different range results in a proper, physically meaningful length scale that is independent of the system size and periodic cell of choice. Only under these conditions 'finite size effects' will vanish for large enough systems (i.e. cells much larger than this characteristic length). Larger simulations are in order, but our computational capabilities forbid it for the time being.

Giménez Molinelli, P. A.; Dorso, C. O.

2015-01-01

329

More about the B and D mesons in nuclear matter

Energy Technology Data Exchange (ETDEWEB)

We calculate the shifts in decay constants of the pseudoscalar B and D mesons in nuclear medium in the frame work of QCD sum rules. We write those shifts in terms of the B - N and D - N scattering lengths and an extra phenomenological parameter entered to calculations. Computing an appreciate forward scattering correlation function, we derive the QCD sum rules for the B - N and D - N scattering lengths and the extra phenomenological parameter in terms of various operators in nuclear medium. We numerically find the values of the shifts in the decay constants compared to their vacuum values. Using the sum rules obtained, we also determine the shifts in the masses of these particles due to nuclear matter and compare the results obtained with the previous predictions in the literature. (orig.)

Azizi, K. [Dogus University, Department of Physics, Istanbul (Turkey); Er, N. [Abant Izzet Baysal University, Department of Physics, Bolu (Turkey); Sundu, H. [Kocaeli University, Department of Physics, Izmit (Turkey)

2014-08-15

330

Nuclear Transparency Effect in the Strongly Interacting Matter

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

331

Neutron skin and nuclear matter equation of state

International Nuclear Information System (INIS)

The equation of state of nuclear matter, which consists of neutrons and protons, has the term that depends on the difference between the neutron and proton densities. Determination of the term, the symmetry energy term, is quite important for nuclear physics as well as nuclear astrophysics. The symmetry energy is one of key ingredients to determine e.g. the radius and internal structure of a neutron star as well as supernoval explosion dynamics. The first order density dependence, slop parameter, of the symmetry energy has a close correlation with the thickness of the neutron skin, which is a neutron rich layer than appears on the surface of heavy nuclei. We pick up three recent measurements on the neutron skin thickness of the 208Pb nucleus by using each of weak, electromagnetic, and strong interactions, and report the present situation on the determination of the slope parameter. (author)

332

The phase transition from nuclear matter to quark matter during proto-neutron star evolution

We explore the occurrence of a phase transition from nuclear matter to quark matter in proto-neutron stars. To this end, we employ recent results on such a phase transition in the presence of an electron-neutrino-degenerate gas, based on a mean field model nuclear equation of state together with a quark matter equation of state as described by the MIT `bag model'. Those results show that this neutrino gas does not favour the transition. By comparison with the proto-neutron star evolutionary calculations of Keil & Janka, we find that, if the bag constant B has a value B = 100 MeV fm^-3, the phase transition is delayed by the presence of neutrinos by a few seconds after core bounce, thus providing a natural explanation for the second peak of neutrino emission detected in SN 1987A by the Kamiokande Group. The transition to quark matter and its subsequent decay should affect proto-neutron star evolution and supernova explosions in a non-trivial way.

Benvenuto, O. G.; Lugones, G.

1999-04-01

333

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

334

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.

Wolniak Stephen M

2011-10-01

335

Properties of rho and eta mesons in nuclear matter

International Nuclear Information System (INIS)

The properties of ?- and ?-mesons in nuclear matter are studied within the scope of hadronic models. Unknown model parameters are obtained from fits to scattering data. - The treatment of the ?-meson includes the coupling to two pions which, in matter, are strongly mixed with delta-particle-nucleon-hole states. The ?-meson self-energy is evaluated in a current conserving approximation with in-medium pion propagators and vertex corrections. While the position of the original peak in the spectral function remains almost unchanged, its width grows rapidly with increasing density. Consequently, the ?-meson strength function is strongly dispersed at high densities. Due to vertex corrections a new peak at a mass around 3m? emerges with increasing density, while the spectral function around the two-pion threshold is found to be smooth at all densities. The ?-meson is strongly mixed with N*(1535)-particle-nucleon-hole states in nuclear matter. The corresponding dispersion relations with an upper and a lower branch look similar to those of the (?, ?N-1)-modes. However, since the N* is an S-wave resonance in the ?N-channel, the repulsion of the two branches survives at zero momentum. (orig.)

336

Spin instabilities of infinite nuclear matter and effective tensor interactions

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 sizable 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 symmetric nuclear matter as well as for neutron matter. A comparison with the spin susceptibility provided by realistic interactions is also presented.

Navarro, J.; Polls, A.

2013-04-01

337

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)

338

Composition and thermodynamics of nuclear matter with light clusters

We investigate nuclear matter at finite temperature and density, including the formation of light clusters up to the alpha particle. The novel feature of this work is to include the formation of clusters as well as their dissolution due to medium effects in a systematic way using two many-body theories: a microscopic quantum statistical (QS) approach and a generalized relativistic mean field (RMF) model. Nucleons and clusters are modified by medium effects. Both approaches reproduce the limiting cases of nuclear statistical equilibrium (NSE) at low densities and cluster-free nuclear matter at high densities. The treatment of the cluster dissociation is based on the Mott effect due to Pauli blocking, implemented in slightly different ways in the QS and the generalized RMF approaches. We compare the numerical results of these models for cluster abundances and thermodynamics in the region of medium excitation energies with temperatures T <= 20 MeV and baryon number densities from zero to a few times saturatio...

Typel, S; Klähn, T; Blaschke, D; Wolter, H H

2009-01-01

339

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

340

Extraction of nuclear matter properties from nuclear masses by a model of equation of state

The extraction of nuclear matter properties from measured nuclear masses is investigated in the energy density functional formalism of nuclei. It is shown that the volume energy $a_1$ and the nuclear incompressibility $K_0$ depend essentially on $\\mu_n N+\\bar{\\mu}_p Z-2E_N$, whereas the symmetry energy $J$ and the density symmetry coefficient $L$ as well as symmetry incompressibility $K_s$ depend essentially on $\\mu_n-\\bar{\\mu}_p$, where $\\bar{\\mu}_p=\\mu_p-\\partial E_C/\\part...

Chung, K. C.; Wang, C. S.; Santiago, A. J.

2001-01-01

341

Neutrino Bremsstrahlung in Neutron Matter from Effective Nuclear Interactions

We revisit the emissivity from neutrino pair bremsstrahlung in neutron-neutron scattering, nn -> nn nu nubar, which was calculated from the one-pion exchange potential including correlation effects by Friman and Maxwell. Starting from the free-space low-momentum nucleon-nucleon interaction V_{low k}, we include tensor, spin-orbit and second-order medium-induced non-central contributions to the scattering amplitude in neutron matter. We find that the screening of the nucleon-nucleon interaction reduces the emissivity from neutrino bremsstrahlung for densities below nuclear matter density. We discuss the implications of medium modifications for the cooling of neutron stars via neutrino emission, taking into account recent results for the polarization effects on neutron superfluidity.

Schwenk, A; Gale, C

2004-01-01

342

Neutrino bremsstrahlung in neutron matter from effective nuclear interactions

International Nuclear Information System (INIS)

We revisit the emissivity from neutrino pair bremsstrahlung in neutron-neutron scattering, nn?nn??-bar, which was calculated from the one-pion exchange potential including correlation effects by Friman and Maxwell. Starting from the free-space low-momentum nucleon-nucleon interaction Vlowk, we include tensor, spin-orbit and second-order medium-induced non-central contributions to the scattering amplitude in neutron matter. We find that the screening of the nucleon-nucleon interaction reduces the emissivity from neutrino bremsstrahlung for densities below nuclear matter density. We discuss the implications of medium modifications for the cooling of neutron stars via neutrino emission, taking into account recent results for the polarization effects on neutron superfluidity

343

Analysis of Boltzmann-Langevin dynamics in nuclear matter

The Boltzmann-Langevin dynamics of harmonic modes in nuclear matter is analyzed within linear-response theory, both with an elementary treatment and by using the frequency-dependent response function. It is shown how the source terms agitating the modes can be obtained from the basic BL correlation kernel by a simple projection onto the associated dual basis states, which are proportional to the RPA amplitudes and can be expressed explicitly. The source terms for the correlated agitation of any two such modes can then be extracted directly, without consideration of the other modes. This facilitates the analysis of collective modes in unstable matter and makes it possible to asses the accuracy of an approximate projection technique employed previously.

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

1995-01-01

344

A correlated-basis-functions approach to realistic nuclear matter

International Nuclear Information System (INIS)

The method of correlated basis functions is adapted to the nuclear-matter problem with two-nucleon potentials containing tensor as well as central components. Proceedures are described for evaluating through three-body cluster order the energy expectation value with respect to a constrained trial ground-state wave function incorporating tensor and central correlations, and for calculating in two-body cluster approximation the second-order perturbation correction in a basis of likewise-correlated functions. Results for the 5100, 5200, Gammel-Christian-Thaler and Hamada-Johnston potentials are presented and dissected. (Auth.)

345

Electric-dipole sum rule in correlated nuclear matter

International Nuclear Information System (INIS)

The enhancement of the photonuclear Thomas-Reiche-Kuhn E1 sum rule due to exchange forces is studied in the large-A (nuclear matter) limit, neglecting retardation effects. Semi-realistic non-central models of the nucleon-nucleon interaction (Gammel-Christian-Tahler, Hamada-Johnston ?6 and Reid ?6) are employed, together with variational ground-state wave functions incorporating state-dependent correlations. The resulting theoretical estimates of the enhancement factor K are in generally good agreement with the value K = 0.75 +- 0.15 (essentially independent of A) implied by the recent Saclay measurements of photoneutron yields in heavy nuclei. (orig.)

346

Thermostatic properties of semi-infinite polarized nuclear matter

International Nuclear Information System (INIS)

The surface and curvature properties of semi-infinite polarized nuclear matter (SPNM) are calculated using an expansion for the Fermi integrals up to T2. A density matrix expansion is obtained for a modified form of Seyler-Blanchard interaction. New parameters that characterize the surface and curvature properties of SPNM are introduced. The level density parameter is extracted from the low temperature expansion of the free energy and compared with previous calculations. A reasonable agreement is obtained for the parameters calculated before. (author). 78 refs, 1 fig., 5 tabs

347

High-density nuclear matter with nonlocal confining solitons

International Nuclear Information System (INIS)

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

348

A QCD sum rule study of ?+ in nuclear matter

International Nuclear Information System (INIS)

We consider a [ud]2s-bar current, in the finite-density QCD sum rule approach, to investigate the scalar and vector self-energies of the recently observed pentaquark state ?+(1540), propagating in nuclear matter. We find that, opposite to what was obtained for the nucleon, the vector self-energy is negative, and the scalar self-energy is positive. There is a substantial cancellation between them resulting in an attractive net self-energy of the same order as in the nucleon case

349

SU(3) string-flip potential models and nuclear matter

International Nuclear Information System (INIS)

A Monte Carlo model for nuclear matter using a many-body SUc(3) string-flip potential, with fixed colour, is investigated. The potential is approximated by considering colour-singlet flux-tube formations that connect only three quarks at a time. The model is compared with a similar string-flip model, proposed by C. J. Horowitz and J. Piekarewicz (1991), that approximates higher-order flux-tube formations by connecting quarks in colour-singlet chains. The former model gives an EMC nucleon ''swelling'' effect, whereas the latter gives an opposite effect. Possible discrepancies between the two models are discussed. ((orig.))

350

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

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

Arnold, Oliver

2014-03-01

351

Pion production as a test of nuclear matter properties

International Nuclear Information System (INIS)

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

352

Coupling and decoupling of pions and deltas in nuclear matter

International Nuclear Information System (INIS)

We implement the delta-hole model for pions in nuclear matter, including self-consistent real and imaginary self energies for both pions and deltas via dispersion relations cut off by form factors. The real part of the pion inverse propagator vanishes at only one energy for each momentum, unlike the conventional picture of level mixing and level repulsion, because of the width of the delta-hole excitation. Results agree with experiments on baryonic charge-exchange reactions and photo-absorption by heavy nuclei. (orig.)

353

Model-space nuclear matter calculations with the Bonn potential

International Nuclear Information System (INIS)

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

354

On direction of propagation of compression wave in nuclear matter

International Nuclear Information System (INIS)

Propagation of compression waves in the nuclear matter is studied. 40Ar nucleus splitting by 1 GeV protons is considered. Events with numbers of secondary tracks 3=7 are selected for an analysis. The inclination of the wave front is found to increase when viscosity is taken into account, resulting in the decrease of the angle of the most probable emission of particles. The estimations for the emission angle almost coincide with the angle of most probable emission of particles, observed experimentally and predicted by the cascade model. It is concluded, that account of viscosity and ensuring the straight-path motion of a source of nuclear density perturbation result in the better agreement of the experimental emission angle with theoretical ones

355

Modification of the $\\omega$-Meson Lifetime in Nuclear Matter

The photo production of $\\omega$ mesons on the nuclei C, Ca, Nb and Pb has been measured using the Crystal Barrel/TAPS detector at the ELSA tagged photon facility in Bonn. The dependence of the $\\omega$ meson cross section on the nuclear mass number has been compared with three different types of models, a Glauber analysis, a BUU analysis of the Giessen theory group and a calculation by the Valencia theory group. In all three cases, the inelastic $\\omega$ width is found to be $130-150 \\rm{MeV/c^2}$ at normal nuclear matter density for an average 3-momentum of 1.1 GeV/c. In the restframe of the $\\omega$ meson, this inelastic $\\omega$ width corresponds to a reduction of the $\\omega$ lifetime by a factor $\\approx 30$. For the first time, the momentum dependent $\\omega$N cross section has been extracted from the experiment and is in the range of 70 mb.

Kotulla, M; Mühlich, P; Anton, G; Bacelar, J C S; Bartholomy, O; Bayadilov, D; Beloglasov, Yu A; Bogendörfer, R; Castelijns, R; Credé, V; Dutz, H; Ehmanns, A; Elsner, D; Ewald, R; Fabry, I; Fuchs, M; Essig, K; Funke, Ch; Gothe, R; Gregor, R; Gridnev, A B; Gutz, E; Höffgen, S; Hoffmeister, P; Horn, I; Hössl, J; Jaegle, I; Junkersfeld, J; Kalinowsky, H; Klein, Frank; Klein, Fritz; Klempt, E; Konrad, M; Kopf, B; Krusche, B; Langheinrich, J; Löhner, H; Lopatin, I V; Lotz, J; Lugert, S; Menze, D; Messchendorp, J G; Mertens, T; Metag, V; Mosel, U; Nanova, M; Novotny, R; Ostrick, M; Pant, L M; Van Pee, H; Pfeiffer, M; Roy, A; Radkov, A; Schadmand, S; Schmidt, Ch; Schmieden, H; Schoch, B; Shende, S; Suft, G; Sumachev, V V; Szczepanek, T; Süle, A; Thoma, U; Varma, R; Walther, D; Weinheimer, Ch; Wendel, Ch

2008-01-01

356

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

357

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

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

Jin, X

1994-01-01

358

Composition and thermodynamics of nuclear matter with light clusters

We investigate nuclear matter at a finite temperature and density, including the formation of light clusters up to the ? particle (1?A?4). The novel feature of this work is to include the formation of clusters as well as their dissolution due to medium effects in a systematic way using two many-body theories: a microscopic quantum statistical (QS) approach and a generalized relativistic mean-field (RMF) model. Nucleons and clusters are modified by medium effects. While the nucleon quasiparticle properties are determined within the RMF model from the scalar and vector self-energies, the cluster binding energies are reduced because of Pauli blocking shifts calculated in the QS approach. Both approaches reproduce the limiting cases of nuclear statistical equilibrium (NSE) at low densities and cluster-free nuclear matter at high densities. The treatment of the cluster dissociation is based on the Mott effect due to Pauli blocking, implemented in slightly different ways in the QS and the generalized RMF approaches. This leads to somewhat different results in the intermediate density range of about 10-3 to 10-1fm-3, which gives an estimate of the present accuracy of the theoretical predictions. We compare the numerical results of these models for cluster abundances and thermodynamics in the region of medium excitation energies with temperatures T?20 MeV and baryon number densities from zero to a few times saturation density. The effects of cluster formation on the liquid-gas phase transition and on the density dependence of the symmetry energy are studied. It is demonstrated that the parabolic approximation for the asymmetry dependence of the nuclear equation of state breaks down at low temperatures and at subsaturation densities because of cluster formation. Comparison is made with other theoretical approaches, in particular, those that are commonly used in astrophysical calculations. The results are relevant for heavy-ion collisions and astrophysical applications.

Typel, S.; Röpke, G.; Klähn, T.; Blaschke, D.; Wolter, H. H.

2010-01-01

359

Composition and thermodynamics of nuclear matter with light clusters

International Nuclear Information System (INIS)

We investigate nuclear matter at a finite temperature and density, including the formation of light clusters up to the ? particle (1?A?4). The novel feature of this work is to include the formation of clusters as well as their dissolution due to medium effects in a systematic way using two many-body theories: a microscopic quantum statistical (QS) approach and a generalized relativistic mean-field (RMF) model. Nucleons and clusters are modified by medium effects. While the nucleon quasiparticle properties are determined within the RMF model from the scalar and vector self-energies, the cluster binding energies are reduced because of Pauli blocking shifts calculated in the QS approach. Both approaches reproduce the limiting cases of nuclear statistical equilibrium (NSE) at low densities and cluster-free nuclear matter at high densities. The treatment of the cluster dissociation is based on the Mott effect due to Pauli blocking, implemented in slightly different ways in the QS and the generalized RMF approaches. This leads to somewhat different results in the intermediate density range of about 10-3 to 10-1 fm-3, which gives an estimate of the present accuracy of the theoretical predictions. We compare the numerical results of these models for cluster abundances and thermodynamics in the region of medium excitation energies with temperatures T?20 MeV and baryon number densities from zero to a few times saturation density. The effe times saturation density. The effects of cluster formation on the liquid-gas phase transition and on the density dependence of the symmetry energy are studied. It is demonstrated that the parabolic approximation for the asymmetry dependence of the nuclear equation of state breaks down at low temperatures and at subsaturation densities because of cluster formation. Comparison is made with other theoretical approaches, in particular, those that are commonly used in astrophysical calculations. The results are relevant for heavy-ion collisions and astrophysical applications.

360

Momentum dependence of the mean field and equation of state of nuclear matter

International Nuclear Information System (INIS)

The momentum and density dependence of the mean field and other properties of nuclear matter are studied with finite-range effective interactions having different functional forms by evaluating the single-particle momentum distribution function self-consistently. In these calculations relativistic effects and supraluminous behaviour of nuclear matter are also taken into account. The equation of states obtained from these effective interactions are used to study liquid-gas phase transition in nuclear matter

361

Momentum dependence of the mean field and equation of state of nuclear matter

Energy Technology Data Exchange (ETDEWEB)

The momentum and density dependence of the mean field and other properties of nuclear matter are studied with finite-range effective interactions having different functional forms by evaluating the single-particle momentum distribution function self-consistently. In these calculations relativistic effects and supraluminous behaviour of nuclear matter are also taken into account. The equation of states obtained from these effective interactions are used to study liquid-gas phase transition in nuclear matter.

Behera, B.; Routray, T.R.; Sahoo, B.; Satpathy, R.K

2002-03-11

362

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 ...

ANDREAS MARKWITZ; Hopke, Philip K.; DIAH DWIANA LESTIANI; MUHAYATUN SANTOSO

2010-01-01

363

A variational approach to nuclear matter with realistic potentials

International Nuclear Information System (INIS)

A lowest order constrained variational method for calculating the binding energy of nuclear matter, previously proposed by the present authors, is extended to treat the strong tensor force components of realistic NN potentials. Numerical results are given for three early potentials of Gammel, Christian and Thaler, and reasonable agreement is found with a previous calculation of Ristig, Ter Louw and Clark which included three-body cluster contributions to the energy. A range of five potentials giving good fits to the experimental two-body NN data is also studied, and binding energies of typically 22 MeV per nucleon at saturation densities corresponding to ksub(F) approximately 1.6-1.7 fm-1, are found. For three of the potentials considered, comparison is made with the recent results of Pandharipande and Wiringa, which include the contributions to the energy from all of the most significant many-body clusters, and excellent agreement is found. It is suggested that explicit inclusion of some of the neglected internal degrees of freedom of the nucleons, such as the possibility of excitation to ?(1236) states, might bring the equilibrium nuclear matter results closer to the empirical values. (Auth.)

364

Non-Abelian energy loss in cold nuclear matter

International Nuclear Information System (INIS)

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

365

Pure Neutron Matter Constraints and Nuclear Symmetry Energy

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

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

2012-01-01

366

Effect of nuclear response functions in dark matter direct detection

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

Gresham, Moira I.; Zurek, Kathryn M.

2014-06-01

367

Chiral condensate in neutron matter

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

Kaiser, N.; Weise, W.

2008-01-01

368

Modification of the ?-Meson Lifetime in Nuclear Matter

International Nuclear Information System (INIS)

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

369

Global analysis of J/? suppression in cold nuclear matter

International Nuclear Information System (INIS)

Interpreting the J/? suppression reported in nucleus-nucleus collisions at SPS and RHIC requires a quantitative understanding of cold nuclear-matter effects, such as the inelastic rescattering of J/? states in nuclei or the nuclear modification of parton densities. With respect to our former Glauber analysis, we include in the present work the new PHENIX d-Au measurements, and we analyze as well all existing data using the EPS08 nuclear parton densities recently released. The largest suppression reported in the new PHENIX analysis leads in turn to an increase of ?J/?N from 3.5±0.3 to 5.4±2.5 mb using the PDF of the proton. The stronger x-dependence of the GA/Gp ratio in EPS08 as compared to e.g. EKS98 shifts the cross section towards larger values at fixed-target energies (x2?0.1), while decreasing somehow the value extracted at RHIC (x2?10-2). (orig.)

370

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

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

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

1995-01-01

371

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

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

CERN. Geneva

2013-01-01

372

Directory of Open Access Journals (Sweden)

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

G. H. Bordbar

2001-12-01

373

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

International Nuclear Information System (INIS)

Delta and pion abundancies in hot dense nuclear matter are calculated self-consistently with 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.)

374

On the elliptical flow in asymmetric collisions and nuclear equation of state

We here present the results of elliptical flow for the collision of different asymmetric nuclei (10Ne20 +13 Al27, 18Ar40 +21 Sc45, 30Zn64 +28 Ni58, 36Kr86 +41 Nb93) by using the Quantum Molecular Dynamics (QMD) model. General features of elliptical flow are investigated with the help of theoretical simulations. The simulations are performed at different beam energies between 40 and 105 MeV/nucleon. A significant change can be seen from in-plane to out-of-plane elliptical flo...

Kaur, Varinderjit; Kumar, Suneel

2010-01-01

375

Dispersion relations of mesons in symmetric nuclear matter

We calculate dispersion relations and propagators for the $\\sigma$, $\\omega$, $\\pi$, $\\rho$, $\\delta$, $\\eta$ and $a_1$ mesons in relativistic, dense, hot, symmetric nuclear matter. In addition to the usual mixing of the $\\sigma-\\omega$ system, we obtain mixing of the $\\delta$ with the longitudinal $\\rho$ mode and of the tranverse $\\rho$ with the transverse $a_1$ mode. Finally, the component of the $a_1$ polarization along the transferred momentum modifies the in-medium pion propagator in a way similar to the Migdal contact interaction, but with the opposite sign. The spurious pion condensate as well as the additional contribution from the $a_1$ meson are removed by a contact term. We compare two ways of implementing contact term subtraction.

Mornas, L

2001-01-01

376

The spin-isospin symmetry energy of nuclear matter

International Nuclear Information System (INIS)

The spin-isospin symmetry energy of nuclear matter, epsilon sub(?)sub(tau), is calculated within the frame of the K matrix theory, in an approximation in which the K matrix depends on a single density. Results obtained for epsilon sub(?)subtau) with the Brueckner-Gammel Thaler and the Reid soft core potential, together with previous results for the isospin and spin symmetry energies, epsilon sub(tau) and epsilon sub(?) are presented and discussed. The most reliable result is : epsilon sub(tau) = 53 MeV, epsilon sub(?)=65 MeV, epsilon sub(?)sub(tau)=76 MeV, in a reasonable agreement with that obtained with the ''empirical'' Landau parameters. (author)

377

Model for nuclear matter in terms of quark clusters

International Nuclear Information System (INIS)

The authors investigate the question of how a system of quarks can exhibit the dynamical properties of nuclear matter as a collection of bound clusters of quarks, based on the notion that each nucleon consists of three quarks coupled into a color neutral state. In the simple model, the author considers non-relativistic quarks with three colors but no spin or flavor, interacting through a one-dimensional ?-function force in a box. The color confinement of the whole system is achieved by a boundary condition, but quarks are only dynamically confined to each nucleon as a result of the clustering mechanism generated by the quark-quark interaction. The authors uses the variational method as an approximation because it is applicable to more general modes including spin and flavor in three-dimensional space

378

Temperature dependence of the response function of hot nuclear matter

International Nuclear Information System (INIS)

The description of collective motion in nuclei at finite temperature using the framework of the random phase approximation is discussed. We focus on the special case of the isovector response function of hot nuclear matter using various effective Skyrme interactions. For such interactions analytic expressions for the response function were derived. From these analytic formulae we shown that one can gain an understanding of the temperature dependence of the giant dipole resonance in finite nuclei. We showed that zero sound type modes become less collective as temperature rises and sometimes disappear at temperatures of a few MeV. We also shown that for effective interactions with an effective mass close to unite, collective effects are small already at zero temperature and depend weakly on temperature. We will thus argue that the temperature dependence of the giant dipole resonance provides valuable information on the effective interactions. (authors)

379

Collective expansion of hot and compressed nuclear matter

International Nuclear Information System (INIS)

Central collisions of Au + Au at incident energies of 90, 150, 250 and 400 A· MeV were studied with the complete FOPI - facility at GSI Darmstadt. The complete phase space distributions at 250 A· MeV confirms the spherical symmetry. The energies corresponding to the onset of collective expansion and side-flow are obtained and compared with the transition energies at which the azimuthal distributions show a change from in-plane to out-of-plane enhancement. A semianalytical model for the expansion and clusterization of hot and compressed nuclear matter is used to explain some of the experimental trends. Modulation of the mean value and the slope of the energy spectra for different fragments as a function of azimuth is evidenced for mid-central collisions. (authors)

380

Study of the ?(1116 interaction in cold nuclear matter

Directory of Open Access Journals (Sweden)

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

Arnold Oliver

2014-03-01

381

Resilience of nuclear matter in light ion induced reactions

International Nuclear Information System (INIS)

Cavitation and heating of the target nucleus in the first instances of 3He-induced collisions in the GeV/u range are investigated in an intranuclear cascade model for the formation of this structure and a stochastic one-body dynamics calculation to study its evolution. The hard collisions having essentially ceased when the structure is fully developed, the latter model is particularly suited to study the possible break-up of the system. It is shown, however, that the target recovers a spherical shape rather rapidly, and has thus a good chance to decay by standard evaporation, justifying the use of a cascade + evaporation model to analyze the data. It is also shown that the system should be modified to break up into pieces instead of recovering a compact shape: in these reactions, it is thus expected that nuclear matter is resilient to shape deformation and thermal excitation. (author)

382

The external field in Brueckners theory of nuclear matter

International Nuclear Information System (INIS)

The authors first present a critical discussion of some possible choices of the external potential U which plays a fundamental role in Brueckner's theory of nuclear matter, and is presently a debated matter. Attention is discussed on two choices, namely the standard one in which U is set to zero for particle states, and a continuous choice in which U is calculated self-consistently for all momenta. Then, the binding energy obtained from these two choices in the Brueckner-Hartree-Fock or in the renormalized Brueckner-Hartree-Fock approximations is compared to the upper bounds derived from recent variational calculations in three cases: the interaction of Baker, Hind and Kahane, that of Ohmura, Morita and Yamada, and the potential of Gammel and Thaler which contains a tensor component. It is concluded that the continuous choice appears more favourable, both from the formal and numerical points of view. For both choices, however, higher order corrections to the Brueckner-Hartree-Fock approximations are sizeable. (Auth.)

383

Short-range correlations in quark and nuclear matter

Energy Technology Data Exchange (ETDEWEB)

In the first part of this thesis, the role of short-range correlations in quark matter is explored within the framework of the Nambu-Jona-Lasinio model. Starting from a next-to-leading order expansion in the inverse number of the quark colors, a fully self-consistent model constructed that employs the close relations between spectral functions and self-energies. In contrast to the usual quasiparticle approximations, this approach allows the investigation of the collisional broadening of the quark spectral function. Numerical calculations at various chemical potentials and zero temperature show that the short-range correlations do not only induce a finite width of the spectral function but also have some influence on the structure of the chiral phase transition. In the second part of this thesis, the temperature and density dependence of the nucleon spectral function in symmetric nuclear matter is investigated. The short-range correlations can be well described by a simple, self-consistent model on the one-particle-two-hole and two-particle-one-hole level (1p2h, 2p1h). The thermodynamically consistent description of the mean-field properties of the nucleons is ensured by incorporating a Skyrme-type potential. Calculations at temperatures and densities that can also be found in heavy-ion collisions or supernova explosions and the formation of neutron stars show that the correlations saturate at high temperatures and densities. (orig.)

Froemel, Frank

2007-06-15

384

The effect of elastic properties of nuclear matter on nuclear fission

International Nuclear Information System (INIS)

Spheroidal nuclear vibrations are considered using a macroscopic model based on the assumption that nuclear matter possesses the properties of elastic medium. Emphasis is laid on the analysis of instability of the quadrupole configuration. It is presumed that the onset of this instability is associated with the commencement of fission. The proposed fluid-dynamics model predicts the values of the parameters of nuclear fission that differ somewhat from the values given by the standard liquid drop-model. In particular, the obtained critical ratio Z2/A, which characterizes the loss of stability of the quadrupole mode, is equal to 35. It follows from this estimate that fission induced by an external perturbation should be expected for nuclei (from the ?-stability valley) with A?230. 16 refs

385

The effect of elastic properties of nuclear matter on nuclear fission

Energy Technology Data Exchange (ETDEWEB)

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

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

1994-07-01

386

Stability and size of a chiral soliton immersed in nuclear matter

International Nuclear Information System (INIS)

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

387

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

International Nuclear Information System (INIS)

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

388

The properties of spin polarized pure neutron matter and symmetric nuclear matter are studied using the finite range simple effective interaction, upon its parametrization revisited. Out of the total twelve parameters involved, we now determine ten of them from nuclear matter, against the nine parameters in our earlier calculation, as required in order to have predictions in both spin polarized nuclear matter and finite nuclei in unique manner being free from uncertainty found using the earlier parametrization. The information on the effective mass splitting in polarized neutron matter of the microscopic calculations is used to constrain the one more parameter, that was earlier determined from finite nucleus, and in doing so the quality of the description of finite nuclei is not compromised. The interaction with the new set of parameters is used to study the possibilities of ferromagnetic and antiferromagnetic transitions in completely polarized symmetric nuclear matter. Emphasis is given to analyze the resul...

Behera, B; Routray, T R; Centelles, M

2015-01-01

389

Directional Search for Isospin-Violating Dark Matter with Nuclear Emulsion

Some of direct dark matter searches reported not only positive signals but also annual modulation of the signal event. However, the parameter spaces have been excluded by other experiments. Isospin violating dark matter solves the contradiction by supposing different coupling to proton and neutron. We study the possibility to test the favored parameter region by isospin violating dark matter model with the future detector of dark matter using the nuclear emulsion. Since the nuclear emulsion detector has directional sensitivity, the detector is expected to examine whether the annual modulations observed other experiments is caused by dark matter or background signals.

Nagao, Keiko I

2012-01-01

390

Self-consistent tensor effects on nuclear matter systems within a relativistic Hartree-Fock approach

With the relativistic representation of the nuclear tensor force that is included automatically by the Fock diagrams, we explored the self-consistent tensor effects on the properties of a nuclear matter system. The analysis was performed within the density-dependent relativistic Hartree-Fock (DDRHF) theory. The tensor force is found to notably influence the saturation mechanism, the equation of state, and the symmetry energy of nuclear matter, as well as the neutron star properties. Without introducing any additional free parameters, the DDRHF approach is a natural way to reveal the tensor effects on the nuclear matter system.

Jiang, Li Juan; Yang, Shen; Dong, Jian Min; Long, Wen Hui

2015-02-01

391

Effect of in-medium hadron parameter modification on nuclear matter equation of state

International Nuclear Information System (INIS)

Equation of state (EOS) of nuclear matter calculated with two body nucleon-nucleon (NN) potential in the traditional Brueckner-Bethe-Goldstone (BBG) formalism or variational formalism, does not reproduce the ground state saturation properties of nuclear matter. The effect on the nuclear matter equation of state due to modification of hadron parameters in nuclear medium as a consequence of partial restoration of chiral symmetry is investigated. Prescriptions suggested by Brown-Rho scaling and QCD sum rule have been used for finding the extent of modification of hadron parameters

392

Momentum and density dependence of the mean field in nuclear matter

International Nuclear Information System (INIS)

The momentum and density dependence of the single particle potential in nuclear matter is crucial in ascertaining a correct mean field which is the basic input in the Boltzmann transport equation used in the description of heavy-ion collision data at intermediate and high energies and also in the calculation of equation of state of nuclear matter at highly non-equilibrium situations. The purpose of this work is to construct such an effective interaction which could give appropriate high momentum and high density behavior of the nuclear mean field as well as reproduce the correct nuclear matter characteristics

393

Self-consistent tensor effects on nuclear matter system under relativistic Hartree-Fock approach

With the relativistic representation of the nuclear tensor force that is included automatically by the Fock diagrams, we explored the self-consistent tensor effects on the properties of nuclear matter system. The analysis were performed within the density-dependent relativistic Hartree-Fock (DDRHF) theory. The tensor force is found to notably influence the saturation mechanism, the equation of state and the symmetry energy of nuclear matter, as well as the neutron star properties. Without introducing any additional free parameters, the DDRHF approach paves a natural way to reveal the tensor effects on the nuclear matter system.

Jiang, Li Juan; Dong, Jian Min; Long, Wen Hui

2014-01-01

394

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

Directory of Open Access Journals (Sweden)

Full Text Available The neutron-proton mass di?erence in (isospin asymmetric nuclear matter and ?nite nuclei is studied in the framework of a medium-modi?ed Skyrme model. The proposed e?ective Lagrangian incorporates both the medium in?uence of the surrounding nuclear environment on the single nucleon properties and an explicit isospin-breaking e?ect in the mesonic sector. Energy-dependent charged and neutral pion optical potentials in the s- and p-wave channels are included as well. The present approach predicts that the neutron-proton mass di?erence is mainly dictated by its strong part and that it markedly decreases in neutron matter. Furthermore, the possible interplay between the e?ective nucleon mass in ?nite nuclei and the Nolen-Schi?er anomaly is discussed. In particular, we ?nd that a correct description of the properties of mirror nuclei leads to a stringent restriction of possible modi?cations of the nucleon’s e?ective mass in nuclei.

Yakhshiev U.T.

2010-04-01

395

For transport model simulations of collisions between two nuclei which have $N/Z$ significantly different from unity one needs a one-body potential which is both isospin and momentum dependent. This work provides sets of such potentials.

Das, C B; Gale, C; Li, B A; Li, Bao-An

2003-01-01

396

Self-consistent tensor effects on nuclear matter system under relativistic Hartree-Fock approach

With the relativistic representation of the nuclear tensor force that is included automatically by the Fock diagrams, we explored the self-consistent tensor effects on the properties of nuclear matter system. The analysis were performed within the density-dependent relativistic Hartree-Fock (DDRHF) theory. The tensor force is found to notably influence the saturation mechanism, the equation of state and the symmetry energy of nuclear matter, as well as the neutron star prope...

Jiang, Li Juan; Yang, Shen; Dong, Jian Min; Long, Wen Hui

2014-01-01

397

Sum rule in nuclear giant monopole resonance and incompressibility of nuclear matter

International Nuclear Information System (INIS)

The isoscalar giant monopole resonance for finite nuclei and the nuclear matter incompressibility are studied in a consistent relativistic approach, which achieves a great success in describing the properties of nuclear ground states. The consistency in the relativistic random phase approximation (RRPA) built on the relativistic mean field (RMF) ground states are investigated. The RMF wave function of nucleus and the particle-hole residual interactions in RRPA are calculated from a same effective Lagrangian. A fully consistent treatment of RRPA with the RMF approximation, i.e. no sea approximation, has to include not only the positive particle-hole excitation, but also the pairs formed from the Dirac states and Fermi states. The energy inverse weighted sum rule for the isoscalar giant monopole resonance is studied in the constrained RMF, which verifies the important contribution from the Dirac state. A comparison between experimental and calculated energies of isoscalar giant monopole energies points to a value of 250-270 MeV for the nuclear matter incompressibility

398

Directional Search for Isospin-Violating Dark Matter with Nuclear Emulsion

Some of direct dark matter searches reported not only positive signals but also annual modulation of the signal event. However, the parameter spaces have been excluded by other experiments. Isospin violating dark matter solves the contradiction by supposing different coupling to proton and neutron. We study the possibility to test the favored parameter region by isospin violating dark matter model with the future detector of dark matter using the nuclear emulsion. Since the ...

Nagao, Keiko I.; Naka, Tatsuhiro

2012-01-01

399

Correlations and pairing in nuclear matter within the Nozieres-Schmitt-Rink approach

International Nuclear Information System (INIS)

The influence of correlations on the critical temperature and density for the onset of superfluidity in nuclear matter is investigated within the scheme of Nozieres and Schmitt-Rink [1]. For symmetric nuclear matter a smooth transition from Bose-Einstein condensation (BEC) of deuteron-like bound states at low densities and low temperatures to Bardeen-Cooper-Schrieffer (BCS) pairing at higher densities is described. Compared with the mean field approach a lowering of the critical temperature is obtained for symmetric nuclear matter as well as for pure neutron matter. The Mott transition in symmetric nuclear matter is discussed. Regions in the temperature-density plane are identified where correlated pairs give the main contribution to the composition of the system, so that approximations beyond the quasi-particle picture are requested. (orig.)

400

Momentum and density dependence of the mean field in nuclear matter

International Nuclear Information System (INIS)

The momentum and density dependence of the mean field in nuclear matter has been studied with phenomenological effective interactions with particular emphasis on the influence of the functional form of the interaction in determining the high density and high momentum behaviour of the mean field. Emphasis is also given to choosing the effective interaction in a form simple enough to permit analytical calculations of various properties of nuclear matter with a minimum number of adjustable parameters. These simple effective interactions are found to have a zero-range density-dependent part similar to Skyrme interactions and a long-range density-independent part of conventional form, such as Yukawa, Gaussian and exponential. It is observed that the high density and the high momentum behaviour of the mean field in nuclear matter is essentially governed by the nature of the density dependence and the precise functional form of the long-range part of the exchange component of the effective interaction. The parameters of these interactions can be constrained to obtain a mean field in nuclear matter which is independent of the functional form of the exchange interaction in the range of momentum k 0-5 fm-1 and up to a density four times the standard nuclear matter density. However, beyond this range the functional form of the exchange interaction becomes important in determining the momentum and density dependence of the mean field in nuclear matter. (author) field in nuclear matter. (author)

401

Compression and speed of sound in nuclear matter

International Nuclear Information System (INIS)

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

402

Resilience of nuclear matter in light ion induced reactions

International Nuclear Information System (INIS)

Cavitation and heating of the target nucleus in the first instances of 3He-induced collisions in the GeV/nucleon range are investigated in an intranuclear cascade model for the formation of this structure and a stochastic one-body dynamics calculation to study its evolution. The hard collisions having essentially ceased when the structure is fully developed, the latter model is particularly suited to study the possible breakup of the system. It is shown, however, that the target recovers a spherical shape rather rapidly, and has thus a good chance to decay by standard evaporation, justifying the use of a cascade + evaporation model to analyze the data. It is also shown that the system has to be much more modified to break up into pieces instead of recovering a compact shape: in these reactions, it is thus expected that nuclear matter is resilient to shape deformation and thermal excitation. Arguments are given to explain that expansion of the system, not important in these reactions, is required to overcome this resilience. copyright 1997 The American Physical Society

403

Spin instabilities of infinite nuclear matter and effective tensor interactions

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

404

Resilience of nuclear matter in light ion induced reactions

Energy Technology Data Exchange (ETDEWEB)

Cavitation and heating of the target nucleus in the first instances of {sup 3}He-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} {ital 1997} {ital The American Physical Society}

Colonna, M.; Cugnon, J.; Pollacco, E.C. [CEA DAPNIA, CE Saclay, F-91191 Gif-sur-Yvette Cedex (France)

1997-03-01

405

Analysis of the heavy mesons in the nuclear matter with the QCD sum rules

In this article, we calculate the contributions of the nuclear matter induced condensates up to dimension 5, take into account the next-to-leading order contributions of the nuclear matter induced quark condensate, and study the properties of the scalar, pseudoscalar, vector and axial-vector heavy mesons in the nuclear matter with the QCD sum rules in a systematic way. The present predictions for the shifts of the masses and decay constants can be confronted with the experimental data in the future. Furthermore, we study the heavy-meson-nucleon scattering lengths as a byproduct, and obtain the conclusion qualitatively about the possible existence of heavy-meson-nucleon bound states.

Wang, Zhi-Gang

2015-01-01

406

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

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

407

Nuclear ``pasta'' structures in low-density nuclear matter and properties of the neutron-star crust

In the neutron-star crust, nonuniform structure of nuclear matter—called the “pasta” structure—is expected. From recent studies of giant flares in magnetars, these structures might be related to some observables and physical quantities of the neutron-star crust. To investigate the above quantities, we numerically explore the pasta structure with a fully three-dimensional geometry and study the properties of low-density nuclear matter, based on the relativistic mean-field model and the Thomas-Fermi approximation. We observe typical pasta structures for fixed proton number fraction and two of them for cold catalyzed matter. We also discuss the crystalline configuration of “pasta.”

Okamoto, Minoru; Maruyama, Toshiki; Yabana, Kazuhiro; Tatsumi, Toshitaka

2013-08-01

408

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

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

Fantina, A. F.; Chamel, N.; Pearson, J. M.; Goriely, S.

2014-03-01

409

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

International Nuclear Information System (INIS)

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

410

Nuclear matter equation of state including few-nucleon correlations $(A\\leq 4)$

Light clusters (mass number $A \\leq 4$) in nuclear matter at subsaturation densities are described using a quantum statistical approach. In addition to self-energy and Pauli-blocking, effects of continuum correlations are taken into account to calculate the quasiparticle properties and abundances of light elements. Medium-modified quasiparticle properties are important ingredients to derive a nuclear matter equation of state applicable in the entire region of warm dense matter below saturation density. Moreover, the contribution of continuum states to the equation of state is considered. The effect of correlations within the nuclear medium on the quasiparticle energies is estimated. The properties of light clusters and continuum correlations in dense matter are of interest for nuclear structure calculations, heavy ion collisions, and for astrophysical applications such as the formation of neutron stars in core-collapse supernovae.

Röpke, G

2014-01-01

411

Lowest-order and hyper-netted-chain calculations of nuclear matter

International Nuclear Information System (INIS)

Employing two model central interactions the binding energy of nuclear matter is calculated within the framework of the Jastrow variational approach using different types of constrains and including all the contributions from hyper-netted-chain diagrams. (Auth.)

412

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 discrepaprovide 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

413

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

International Nuclear Information System (INIS)

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

414

Relativistic description of exotic nuclei and nuclear matter at extreme conditions

International Nuclear Information System (INIS)

Resent works on the relativistic description of Exotic Nuclei and Nuclear Matter at extreme conditions are reviewed. New parameter sets for the Lagrangian density in the relativistic mean field (RMF) theory are proposed. The density-dependencies of effective interactions in RMF for nuclear matter and neutron stars are discussed.They are able to provide an excellent description also for the nuclei near or far the beta-stability line

415

Fractal structure of near-threshold quarkonium production off cold nuclear matter

We investigate near-threshold production of quarkonium resonances in cold nuclear matter through a scaling theory with two exponents which are fixed by existing data on near-threshold J/psi production in proton-nucleus collisions. Interestingly, it seems possible to extend one of the multifractal dimensions to the production of other mesons in cold nuclear matter. The scaling theory can be tested and refined in experiments at the upcoming high-intensity FAIR accelerator complex in GSI.

Bhaduri, Partha Pratim

2013-01-01

416

Fractal structure of near-threshold quarkonium production off cold nuclear matter

We investigate near-threshold production of quarkonium resonances in cold nuclear matter through a scaling theory with two exponents which are fixed by existing data on near-threshold J/psi production in proton-nucleus collisions. Interestingly, it seems possible to extend one of the multifractal dimensions to the production of other mesons in cold nuclear matter. The scaling theory can be tested and refined in experiments at the upcoming high-intensity FAIR accelerator comp...

Bhaduri, Partha Pratim; Gupta, Sourendu

2013-01-01

417

Do Skyrme forces that fit nuclear matter work well in finite nuclei?

A shortlist of Skyrme force parameterizations, recently found to have passed a series of constraints relating to nuclear matter properties is analyzed for their ability to reproduce data in finite nuclei. We analyse binding energies, isotope shifts and fission barriers. We find that the subset of forces have no common ability to reproduce (or otherwise) properties of finite nuclei, despite passing the extensive range of nuclear matter constraints.

Stevenson, P D; Stone, J R; Dutra, M

2012-01-01

418

From nuclear reactions to compact stars: a unified approach

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 for pure hadronic m...

Basu, D N; Mishra, Abhishek

2014-01-01

419

On the possible existence of magnetic charges in nuclear matter and finite nuclei

International Nuclear Information System (INIS)

Based on the Walecka-Serot theory of nuclei and the Ginzburg-Landau theory of critical phenomena it is shown that the nucleon pairing correlation of superconductivity type certainly leads to the existence of magnetic charges in nuclear matter and finite nuclei. The neutron pairing correlation yields the topological vortices in neutron matter and neutron stars. (author). 8 refs

420

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

We review theoretical approaches to explore the phase diagram of nuclear and quark matter at high baryon density. We first look over the basic properties of quantum chromodynamics (QCD) and address how to describe various states of QCD matter. In our discussions on nuclear matter we cover the relativistic mean-field model, the chiral perturbation theory, and the approximation based on the large-Nc limit where Nc is the number of colors. We then explain the liquid-gas phase transition and the inhomogeneous meson condensation in nuclear matter with emphasis put on the relevance to quark matter. We commence the next part focused on quark matter with the bootstrap model and the Hagedorn temperature. Then we turn to properties associated with chiral symmetry and exposit theoretical descriptions of the chiral phase transition. There emerge some quark-matter counterparts of phenomena seen in nuclear matter such as the liquid-gas phase transition and the inhomogeneous structure of the chiral condensate. The third reg...

Fukushima, Kenji

2013-01-01

421

Momentum and density dependence of the mean field in nuclear matter

Energy Technology Data Exchange (ETDEWEB)

The momentum and density dependence of the mean field in nuclear matter has been studied with phenomenological effective interactions with particular emphasis on the influence of the functional form of the interaction in determining the high density and high momentum behaviour of the mean field. Emphasis is also given to choosing the effective interaction in a form simple enough to permit analytical calculations of various properties of nuclear matter with a minimum number of adjustable parameters. These simple effective interactions are found to have a zero-range density-dependent part similar to Skyrme interactions and a long-range density-independent part of conventional form, such as Yukawa, Gaussian and exponential. It is observed that the high density and the high momentum behaviour of the mean field in nuclear matter is essentially governed by the nature of the density dependence and the precise functional form of the long-range part of the exchange component of the effective interaction. The parameters of these interactions can be constrained to obtain a mean field in nuclear matter which is independent of the functional form of the exchange interaction in the range of momentum k 0-5 fm{sup -1} and up to a density four times the standard nuclear matter density. However, beyond this range the functional form of the exchange interaction becomes important in determining the momentum and density dependence of the mean field in nuclear matter. (author)

Behera, B.; Routray, T.R.; Satpathy, R.K. [Department of Physics, Sambalpur University, Jyoti-Vihar-768019, Burla, Sambalpur, Orissa (India)

1998-11-01

422

Does nuclear fragmentation explore the gas-liquid phase transition of nuclear matter

International Nuclear Information System (INIS)

The phase space of channels is calculated into which a nucleus may decay after being hit by a proton with Esub(p) > 10 GeV. Special care is given to the finite size of the system and to the Coulomb interaction between the fragments. Both effects are shown to be of crucial and dominant importance. At a temperature of 4-5 MeV the target decays into many fragments simultaneously. The mass yields is reproduced by the model over the entire mass range. Monte Carlo simulations show that also the energy spectra may realistically be reproduced and the slope parameter (the apparent temperature) Tsub(app) is --2 times larger than the true temperature. This is due to considerable fluctuations in the number of fragments and in their mutual Coulomb-interaction. The gasliquid phase transition in nuclear matter is dramatically modified by these finite size and strong Coulomb effects. Some general features of this transition are discussed. (author)

423

Quark matter and nuclear collisions a brief history of strong interaction thermodynamics

International Nuclear Information System (INIS)

The past 50 years have seen the emergence of a new field of research in physics, the study of matter at extreme temperatures and densities. The theory of strong interactions, quantum chromodynamics (QCD), predicts that in this limit, matter will become a plasma of deconfined quarks and gluons — the medium which made up the early universe in the first 10 microseconds after the Big Bang. High energy nuclear collisions are expected to produce short-lived bubbles of such a medium in the laboratory. I survey the merger of statistical QCD and nuclear collision studies for the analysis of strongly interacting matter in theory and experiment. (author)

424

Comparative study of three-nucleon force models in nuclear matter

We calculate the energy per particle of symmetric nuclear matter and pure neutron matter using the microscopic many-body Brueckner-Hartree-Fock (BHF) approach and employing the Argonne V18 (AV18) nucleon-nucleon (NN) potential supplemented with two different three-nucleon force models recently constructed to reproduce the binding energy of $^3$H, $^3$He and $^4$He nuclei as well as the neutron-deuteron doublet scattering length. We find that none of these new three-nucleon force models is able to reproduce simultaneously the empirical saturation point of symmetric nuclear matter and the properties of three- and four-nucleon systems.

Logoteta, Domenico; Bombaci, Ignazio; Kievsky, Alejandro

2015-01-01

425

International Nuclear Information System (INIS)

Various 2H and 31P nuclear magnetic resonance (NMR) spectroscopy techniques are applied to probe the component dynamics of the binary glass former tripropyl phosphate (TPP)/polystyrene-d3 (PS) over the full concentration range. The results are quantitatively compared to those of a dielectric spectroscopy (DS) study on the same system previously published [R. Kahlau, D. Bock, B. Schmidtke, and E. A. Rössler, J. Chem. Phys. 140, 044509 (2014)]. While the PS dynamics does not significantly change in the mixtures compared to that of neat PS, two fractions of TPP molecules are identified, one joining the glass transition of PS in the mixture (?1-process), the second reorienting isotropically (?2-process) even in the rigid matrix of PS, although at low concentration resembling a secondary process regarding its manifestation in the DS spectra. Pronounced dynamical heterogeneities are found for the TPP ?2-process, showing up in extremely stretched, quasi-logarithmic stimulated echo decays. While the time window of NMR is insufficient for recording the full correlation functions, DS results, covering a larger dynamical range, provide a satisfactory interpolation of the NMR data. Two-dimensional 31P NMR spectra prove exchange within the broadly distributed ?2-process. As demonstrated by 2H NMR, the PS matrix reflects the faster ?2-process of TPP by performing a spatially highly hindered motion on the same timescale

426

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

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

427

Energy Technology Data Exchange (ETDEWEB)

Various {sup 2}H and {sup 31}P nuclear magnetic resonance (NMR) spectroscopy techniques are applied to probe the component dynamics of the binary glass former tripropyl phosphate (TPP)/polystyrene-d{sub 3} (PS) over the full concentration range. The results are quantitatively compared to those of a dielectric spectroscopy (DS) study on the same system previously published [R. Kahlau, D. Bock, B. Schmidtke, and E. A. Rössler, J. Chem. Phys. 140, 044509 (2014)]. While the PS dynamics does not significantly change in the mixtures compared to that of neat PS, two fractions of TPP molecules are identified, one joining the glass transition of PS in the mixture (?{sub 1}-process), the second reorienting isotropically (?{sub 2}-process) even in the rigid matrix of PS, although at low concentration resembling a secondary process regarding its manifestation in the DS spectra. Pronounced dynamical heterogeneities are found for the TPP ?{sub 2}-process, showing up in extremely stretched, quasi-logarithmic stimulated echo decays. While the time window of NMR is insufficient for recording the full correlation functions, DS results, covering a larger dynamical range, provide a satisfactory interpolation of the NMR data. Two-dimensional {sup 31}P NMR spectra prove exchange within the broadly distributed ?{sub 2}-process. As demonstrated by {sup 2}H NMR, the PS matrix reflects the faster ?{sub 2}-process of TPP by performing a spatially highly hindered motion on the same timescale.

Bock, D.; Kahlau, R.; Pötzschner, B.; Körber, T.; Wagner, E.; Rössler, E. A., E-mail: ernst.roessler@uni-bayreuth.de [Experimentalphysik II, Universität Bayreuth, 95440 Bayreuth (Germany)

2014-03-07

428

A study of influence of nuclear matter parameters on finite nuclei properties

International Nuclear Information System (INIS)

The study of nuclear matter (NM) and finite nuclei in a given model is a promising area of current nuclear research. The use of effective models have been quite successful in this regard. The relativistic mean field (RMF) theory uses exchange of mesons to account for the interaction part

429

The PHENIX experiment has measured open heavy-flavor production via semileptonic decay over the transverse momentum range 1 < p(T) < 6??GeV/c at forward and backward rapidity (1.4 < |y| < 2.0) in d+Au and p + p collisions at ?sNN = 200??GeV. In central d+Au collisions, relative to the yield in p + p collisions scaled by the number of binary nucleon-nucleon collisions, a suppression is observed at forward rapidity (in the d-going direction) and an enhancement at backward rapidity (in the Au-going direction). Predictions using nuclear-modified-parton-distribution functions, even with additional nuclear-p(T) broadening, cannot simultaneously reproduce the data at both rapidity ranges, which implies that these models are incomplete and suggests the possible importance of final-state interactions in the asymmetric d + Au collision system. These results can be used to probe cold-nuclear-matter effects, which may significantly affect heavy-quark production, in addition to helping constrain the magnitude of charmonia-breakup effects in nuclear matter. PMID:25014805

Adare, A; Aidala, C; Ajitanand, N N; Akiba, Y; Akimoto, R; Al-Bataineh, H; Al-Ta'ani, H; Alexander, J; Andrews, K R; Angerami, A; Aoki, K; Apadula, N; Appelt, E; Aramaki, Y; Armendariz, R; Aschenauer, E C; Atomssa, E T; Averbeck, R; Awes, T C; Azmoun, B; Babintsev, V; Bai, M; Baksay, G; Baksay, L; Bannier, B; Barish, K N; Bassalleck, B; Basye, A T; Bathe, S; Baublis, V; Baumann, C; Bazilevsky, A; Belikov, S; Belmont, R; Ben-Benjamin, J; Bennett, R; Bhom, J H; Blau, D S; Bok, J S; Boyle, K; Brooks, M L; Broxmeyer, D; Buesching, H; Bumazhnov, V; Bunce, G; Butsyk, S; Campbell, S; Caringi, A; Castera, P; Chen, C-H; Chi, C Y; Chiu, M; Choi, I J; Choi, J B; Choudhury, R K; Christiansen, P; Chujo, T; Chung, P; Chvala, O; Cianciolo, V; Citron, Z; Cole, B A; Conesa Del Valle, Z; Connors, M; Csanád, M; Csörg?, T; Dahms, T; Dairaku, S; Danchev, I; Das, K; Datta, A; David, G; Dayananda, M K; Denisov, A; Deshpande, A; Desmond, E J; Dharmawardane, K V; Dietzsch, O; Dion, A; Donadelli, M; Drapier, O; Drees, A; Drees, K A; Durham, J M; Durum, A; Dutta, D; D'Orazio, L; Edwards, S; Efremenko, Y V; Ellinghaus, F; Engelmore, T; Enokizono, A; En'yo, H; Esumi, S; Fadem, B; Fields, D E; Finger, M; Finger, M; Fleuret, F; Fokin, S L; Fraenkel, Z; Frantz, J E; Franz, A; Frawley, A D; Fujiwara, K; Fukao, Y; Fusayasu, T; Gal, C; Garishvili, I; Glenn, A; Gong, H; Gong, X; Gonin, M; Goto, Y; Granier de Cassagnac, R; Grau, N; Greene, S V; Grim, G; Grosse Perdekamp, M; Gunji, T; Guo, L; Gustafsson, H-Å; Haggerty, J S; Hahn, K I; Hamagaki, H; Hamblen, J; Han, R; Hanks, J; Harper, C; Hashimoto, K; Haslum, E; Hayano, R; He, X; Heffner, M; Hemmick, T K; Hester, T; Hill, J C; Hohlmann, M; Hollis, R S; Holzmann, W; Homma, K; Hong, B; Horaguchi, T; Hori, Y; Hornback, D; Huang, S; Ichihara, T; Ichimiya, R; Iinuma, H; Ikeda, Y; Imai, K; Inaba, M; Iordanova, A; Isenhower, D; Ishihara, M; Issah, M; Ivanischev, D; Iwanaga, Y; Jacak, B V; Jia, J; Jiang, X; Jin, J; John, D; Johnson, B M; Jones, T; Joo, K S; Jouan, D; Jumper, D S; Kajihara, F; Kamin, J; Kaneti, S; Kang, B H; Kang, J H; Kang, J S; Kapustinsky, J; Karatsu, K; Kasai, M; Kawall, D; Kawashima, M; Kazantsev, A V; Kempel, T; Khanzadeev, A; Kijima, K M; Kikuchi, J; Kim, A; Kim, B I; Kim, D J; Kim, E-J; Kim, Y-J; Kim, Y K; Kinney, E; Kiss, A; Kistenev, E; Kleinjan, D; Kline, P; Kochenda, L; Komkov, B; Konno, M; Koster, J; Kotov, D; Král, A; Kravitz, A; Kunde, G J; Kurita, K; Kurosawa, M; Kwon, Y; Kyle, G S; Lacey, R; Lai, Y S; Lajoie, J G; Lebedev, A; Lee, D M; Lee, J; Lee, K B; Lee, K S; Lee, S H; Lee, S R; Leitch, M J; Leite, M A L; Li, X; Lichtenwalner, P; Liebing, P; Lim, S H; Linden Levy, L A; Liška, T; Liu, H; Liu, M X; Love, B; Lynch, D; Maguire, C F; Makdisi, Y I; Malik, M D; Manion, A; Manko, V I; Mannel, E; Mao, Y; Masui, H; Matathias, F; McCumber, M; McGaughey, P L; McGlinchey, D; McKinney, C; Means, N; Mendoza, M; Meredith, B; Miake, Y; Mibe, T; Mignerey, A C; Miki, K; Milov, A; Mitchell, J T; Miyachi, Y; Mohanty, A K; Moon, H J; Morino, Y; Morreale, A; Morrison, D P; Motschwiller, S; Moukhanova, T V; Murakami, T; Murata, J; Nagamiya, S; Nagle, J L; Naglis, M; Nagy, M I; Nakagawa, I; Nakamiya, Y; Nakamura, K R; Nakamura, T; Nakano, K; Nam, S; Newby, J; Nguyen, M; Nihashi, M; Nouicer, R; Nyanin, A S; Oakley, C; O'Brien, E; Oda, S X; Ogilvie, C A; Oka, M; Okada, K; Onuki, Y; Oskarsson, A; Ouchida, M; Ozawa, K; Pak, R; Pantuev, V; Papavassiliou, V; Park, B H; Park, I H; Park, S K; Park, W J; Pate, S F; Patel, L; Pei, H; Peng, J-C; Pereira, H; Peressounko, D Yu; Petti, R; Pinkenburg, C; Pisani, R P; Proissl, M; Purschke, M L; Qu, H; Rak, J; Ravinovich, I; Read, K F; Rembeczki, S; Reygers, K; Riabov, V; Riabov, Y; Richardson, E; Roach, D; Roche, G; Rolnick, S D; Rosati, M; Rosen, C A; Rosendahl, S S E; Ruži?ka, P; Sahlmueller, B; Saito, N; Sakaguchi, T; Sakashita, K; Samsonov, V; Sano, S; Sarsour, M; Sato, T; Savastio, M; Sawada, S; Sedgwick, K; Seele, J; Seidl, R; Seto, R; Sharma, D; Shein, I; Shibata, T-A; Shigaki, K; Shim, H H; Shimomura, M; Shoji, K; Shukla, P; Sickles, A; Silva, C L; Silvermyr, D; Silvestre, C; Sim, K S; Singh, B K; Singh, C P; Singh, V; Slune?ka, M; Sodre, T; Soltz, R A; Sondheim, W E; Sorensen, S P; Sourikova, I V; Stankus, P W; Stenlund, E; Stoll, S P; Sugitate, T; Sukhanov, A; Sun, J; Sziklai, J; Takagui, E M; Takahara, A; Taketani, A; Tanabe, R; Tanaka, Y; Taneja, S; Tanida, K; Tannenbaum, M J; Tarafdar, S; Taranenko, A; Tennant, E; Themann, H; Thomas, D; Thomas, T L; Togawa, M; Toia, A; Tomášek, L; Tomášek, M; Torii, H; Towell, R S; Tserruya, I; Tsuchimoto, Y; Utsunomiya, K; Vale, C; Valle, H; van Hecke, H W; Vazquez-Zambrano, E; Veicht, A; Velkovska, J; Vértesi, R; Virius, M; Vossen, A; Vrba, V; Vznuzdaev, E; Wang, X R; Watanabe, D; Watanabe, K; Watanabe, Y; Watanabe, Y S; Wei, F; Wei, R; Wessels, J; White, S N; Winter, D; Woody, C L; Wright, R M; Wysocki, M

2014-06-27

430

International Nuclear Information System (INIS)

Dielectric spectroscopy as well as 2H and 31P nuclear magnetic resonance spectroscopy (NMR) are applied to probe the component dynamics of the binary glass former tripropyl phosphate (TPP)/polystyrene (PS/PS-d3) in the full concentration (cTPP) range. In addition, depolarized light scattering and differential scanning calorimetry experiments are performed. Two glass transition temperatures are found: Tg1(cTPP) reflects PS dynamics and shows a monotonic plasticizer effect, while the lower Tg2(cTPP) exhibits a maximum and is attributed to (faster) TPP dynamics, occurring in a slowly moving or immobilized PS matrix. Dielectric spectroscopy probing solely TPP identifies two different time scales, which are attributed to two sub-ensembles. One of them, again, shows fast TPP dynamics (?2-process), the other (?1-process) displays time constants identical with those of the slow PS matrix. Upon heating the ?1-fraction of TPP decreases until above some temperature Tc only a single ?2-population exists. Inversely, below Tc a fraction of the TPP molecules is trapped by the PS matrix. At low cTPP the ?2-relaxation does not follow frequency-temperature superposition (FTS), instead it is governed by a temperature independent distribution of activation energies leading to correlation times which follow Arrhenius laws, i.e., the ?2-relaxation resembles a secondary process. Yet, 31P NMR demonstrates that it involves isotropic reorientations of TPP molecules within a slowly moving or rigid matrix of PS. At high cTPP the super-Arrhenius temperature dependence of ?2(T), as well as FTS are recovered, known as typical of the glass transition in neat systems

431

Energy Technology Data Exchange (ETDEWEB)

Dielectric spectroscopy as well as {sup 2}H and {sup 31}P nuclear magnetic resonance spectroscopy (NMR) are applied to probe the component dynamics of the binary glass former tripropyl phosphate (TPP)/polystyrene (PS/PS-d{sub 3}) in the full concentration (c{sub TPP}) range. In addition, depolarized light scattering and differential scanning calorimetry experiments are performed. Two glass transition temperatures are found: T{sub g1}(c{sub TPP}) reflects PS dynamics and shows a monotonic plasticizer effect, while the lower T{sub g2}(c{sub TPP}) exhibits a maximum and is attributed to (faster) TPP dynamics, occurring in a slowly moving or immobilized PS matrix. Dielectric spectroscopy probing solely TPP identifies two different time scales, which are attributed to two sub-ensembles. One of them, again, shows fast TPP dynamics (?{sub 2}-process), the other (?{sub 1}-process) displays time constants identical with those of the slow PS matrix. Upon heating the ?{sub 1}-fraction of TPP decreases until above some temperature T{sub c} only a single ?{sub 2}-population exists. Inversely, below T{sub c} a fraction of the TPP molecules is trapped by the PS matrix. At low c{sub TPP} the ?{sub 2}-relaxation does not follow frequency-temperature superposition (FTS), instead it is governed by a temperature independent distribution of activation energies leading to correlation times which follow Arrhenius laws, i.e., the ?{sub 2}-relaxation resembles a secondary process. Yet, {sup 31}P NMR demonstrates that it involves isotropic reorientations of TPP molecules within a slowly moving or rigid matrix of PS. At high c{sub TPP} the super-Arrhenius temperature dependence of ?{sub 2}(T), as well as FTS are recovered, known as typical of the glass transition in neat systems.

Kahlau, R.; Bock, D.; Schmidtke, B.; Rössler, E. A., E-mail: ernst.roessler@uni-bayreuth.de [Experimentalphysik II, Universität Bayreuth, 95440 Bayreuth (Germany)

2014-01-28

432

Study of the nuclear matter distribution of exotic Be and B nuclei

Energy Technology Data Exchange (ETDEWEB)

Exotic nuclei close to the drip-lines have revealed an interesting type of nuclear structure with a widely extended matter distribution of loosely bound valence nucleons(halo) surrounding a compact core. In the present work the differential cross sections for small-angle proton elastic scattering on the {sup 12,14}Be and {sup 8}B isotopes were analyzed. The experiment was performed at energies near 700 MeV/u in inverse kinematics using the active target detector IKAR at GSI, Darmstadt. The measured cross sections were analyzed with the aid of the Glauber multiple-scattering theory. Nuclear matter radii and radial matter distributions have been deduced. The nuclear matter distribution for {sup 14}Be exhibits a pronounced neutron halo structure while for {sup 8}B a proton halo is observed. The obtained data allow for a test of various theoretical model calculations of the structure of the studied isotopes.

Ilieva, S.; Aksouh, F.; Behr, K.H.; Bleile, A.; Bruenle, A.; Egelhof, P.; Geissel, H.; Ickert, G.; Inglessi, A.; Kanungo, R.; Kiselev, O.; Le, X.C.; Litvinov, Y.; Niebur, W.; Nociforo, C.; Weick, H. [Gesellschaft fuer Schwerionenforschung (GSI), Darmstadt (Germany); Alkhazov, G.D.; Dobrovolsky, A.V.; Khanzadeev, A.V.; Korolev, G.A.; Seliverstov, D.M.; Sergeev, L.O.; Vorobyov, A.A.; Yatsoura, V.I.; Zhdanov, A.A. [Petersburg Nuclear Physics Institute (PNPI), Gatchina (Russian Federation); Chulkov, L.; Volkov, V.A. [Kurchatov Institute, Moscow (Russian Federation)

2008-07-01

433

Constraining the nuclear matter equation of state around twice saturation density

Using FOPI data on elliptic flow in Au+Au collisions between 0.4 and 1.5A GeV we extract constraints for the equation of state (EOS) of compressed symmetric nuclear matter using the transport code IQMD by introducing an observable describing the evolution of the size of the elliptic flow as a function of rapidity. This observable is sensitive to the nuclear EOS and a robust tool to constrain the compressibility of nuclear matter up to 2 $\\rho_0$.

Fèvre, A Le; Reisdorf, W; Aichelin, J; Hartnack, Ch

2015-01-01

434

Scalar response of the nucleon chiral symmetry and nuclear matter properties

In this talk we present a description of nuclear binding in a chiral approach based on the existence of a chiral invariant scalar field associated with the generation of the masses through spontaneous chiral symmetry breaking. We discuss the emergence of such a field on the example of the NJL model. We also incorporate the effect of confinement at the level of the nucleon substructure to stabilize nuclear matter. In a particular quark-diquark model we illustrate the simutaneous influences of spontaneous chiral symmetry breaking and confinement on the nucleon mass and on the nuclear matter description.

Chanfray, G

2010-01-01

435

Relativistic effects in the Bethe-Brueckner theory of nuclear matter

International Nuclear Information System (INIS)

We extend the theory of nuclear matter to include a relativistic description of nucleon motion. In particular we allow for negative energy components in the nucleon wave function. The amplitude for these components is calculated using an extended version of the one-boson-exchange model of nuclear forces. We find that the inclusion of negative energy states (pair currents) provides a strongly density dependent repulsive interaction. (If one limits oneself to a description involving positive energy states only, this interaction appears as an effective repulsive many-body force.) Our extended theory leads to major modification of the saturation properties of nuclear matter. For example, a boson-exchange force which, in a standard calculation, leads to significant overbinding of nuclear matter at much too high a saturation density yields, in our relativistic analysis, quite good agreement with the generally accepted empirical values for the binding energy and density of nuclear matter. (This potential has strong tensor coupling for the p meson and a weak tensor force. These features are favored at this time on the basis of other theoretical considerations.) We conclude that, contrary to current thought, nuclear matter should be treated as a relativistic system

436

Appearance of the Single Gyroid Network Phase in Nuclear Pasta Matter

Nuclear matter under the conditions of a supernova explosion unfolds into a rich variety of spatially structured phases, called nuclear pasta. We investigate the role of periodic network-like structures with negatively curved interfaces in nuclear pasta structures, by static and dynamic Hartree-Fock simulations in periodic lattices. As the most prominent result, we identify for the first time the {\\it single gyroid} network structure of cubic chiral $I4_123$ symmetry, a well...

Schuetrumpf, B.; Klatt, M. A.; Iida, K.; Schroeder-turk, G. E.; Maruhn, J. A.; Mecke, K.; Reinhard, P. -g

2014-01-01

437

Nuclear Three-body Force Effect on a Kaon Condensate in Neutron Star Matter

We explore the effects of a microscopic nuclear three-body force on the threshold baryon density for kaon condensation in chemical equilibrium neutron star matter and on the composition of the kaon condensed phase in the framework of the Brueckner-Hartree-Fock approach. Our results show that the nuclear three-body force affects strongly the high-density behavior of nuclear symmetry energy and consequently reduces considerably the critical density for kaon condensation provid...

Zuo, W.; Li, A.; Li, Z. H.; Lombardo, U.

2004-01-01

438

In-medium effective chiral lagrangians and the pion mass in nuclear matter

International Nuclear Information System (INIS)

We argue that the effective pion mass in nuclear matter obtained from chiral effective lagrangians is unique and does not depend on off-mass-shell extensions of the pion fields as e.g. the PCAC choice. The effective pion mass in isospin symmetric nuclear matter is predicted to increase slightly with increasing nuclear density, whereas the effective time-like pion decay constant and the magnitude of the density-dependent quark condensate decrease appreciably. The in-medium Gell-Mann-Oakes-Renner relation as well as other in-medium identities are studied in addition. Finally, several constraints on effective lagrangians for the description of the pion propagation in isospin symmetric, isotropic and homogeneous nuclear matter are discussed. (orig.)

439

The particle-hole interaction and pion condensation in nuclear matter

International Nuclear Information System (INIS)

Following a general introduction in chapter one, the second chapter describes the calculation of the pion p-wave self-energy in nuclear matter. This quantity represents the amount of binding a pion gains by interacting with the medium. The third chapter exploits the formalism developed to work out a simple conclusion which can be drawn from the general notion of the divergence of a series of diagrams. Clearly, if the pion propagator in the medium develops a pole at some density, this implies that the one-pion-exchange NN interaction in the medium will be drastically modified. In Chapter four, the contribution to the binding energy of nuclear matter is calculated for a special set of diagrams - ring diagrams. Finally, in chapter five the low and intermediate momentum components of the nuclear matter G matrix which are relevant for nuclear structure, are studied. (Auth.)

440

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

Energy Technology Data Exchange (ETDEWEB)

Though generally agreed that the symmetry energy plays a dramatic role in determining the structure of neutron stars and the evolution of core-collapsing supernovae, little is known in what concerns its value away from normal nuclear matter density and, even more important, the correct definition of this quantity in the case of unhomogeneous matter. Indeed, nuclear matter traditionally addressed by mean-field models is uniform while clusters are known to exist in the dilute baryonic matter which constitutes the main component of compact objects outer shells. In the present work we investigate the meaning of symmetry energy in the case of clusterized systems and the sensitivity of the proto-neutron star composition and equation of state to the effective interaction. To this aim an improved Nuclear Statistical Equilibrium (NSE) model is developed, where the same effective interaction is consistently used to determine the clusters and unbound particles energy functionals in the self-consistent mean-field approximation. In the same framework, in-medium modifications to the cluster energies due to the presence of the nuclear gas are evaluated. We show that the excluded volume effect does not exhaust the in-medium effects and an extra isospin and density-dependent energy shift has to be considered to consistently determine the composition of subsaturation stellar matter. The symmetry energy of diluted matter is seen to depend on the isovector properties of the effective interaction, but its behavior with density and its quantitative value are strongly modified by clusterization. (orig.)

Raduta, A.R. [IFIN-HH, Bucharest-Magurele (Romania); Aymard, F.; Gulminelli, F. [CNRS, UMR6534, LPC, Caen (France); ENSICAEN, UMR6534, LPC, Caen (France)

2014-02-15

441

International Nuclear Information System (INIS)

Recent developments of gravitational wave detectors like LIGO and Virgo provide us an optimistic opportunity of expecting first few events in near future. One of the exciting possibilities is that we can probe the inner structure of compact objects like neutron star by analyzing the observed pattern of gravitational waves. Among the characteristic features of the equation of state (EoS), the symmetry energy of dense hadronic matter is discussed. A model which implements a new scaling law of physical parameters of hadronic matter is briefly sketched to demonstrate how it affects the equation of state and the outcome for the mass and radius estimation is discussed for an n-p asymmetric configuration

442

Quarkonium suppression in heavy-ion collisions from coherent energy loss in cold nuclear matter

The effect of parton energy loss in cold nuclear matter on the suppression of quarkonia (J/psi, Upsilon) in heavy-ion collisions is investigated, by extrapolating a model based on coherent radiative energy loss recently shown to describe successfully J/psi and Upsilon suppression in proton-nucleus collisions. Model predictions in heavy-ion collisions at RHIC (Au-Au, Cu-Cu, and Cu-Au) and LHC (Pb-Pb) show a sizable suppression arising from the sole effect of energy loss in cold matter. This effect should thus be considered in order to get a reliable baseline for cold nuclear matter effects in quarkonium suppression in heavy-ion collisions, in view of disentangling hot from cold nuclear effects.

Arleo, François

2014-01-01

443

Isospin splitting of nucleon effective mass and shear viscosity of nuclear matter

Based on an improved isospin- and momentum-dependent interaction, we have studied the qualitative effect of isospin splitting of nucleon effective mass on the specific shear viscosity of neutron-rich nuclear matter from a relaxation time approach. It is seen that for $m_n^\\star>m_p^\\star$, the relaxation time of neutrons is smaller and the neutron flux between flow layers is weaker, leading to a smaller specific shear viscosity of neutron-rich matter compared to the case for $m_n^\\star

Xu, Jun

2015-01-01

444

Phase transition patterns of nuclear matter based on extended linear sigma model

International Nuclear Information System (INIS)

We study systematically various types of phase transitions in nuclear matter at finite temperature T and baryon chemical potential ? based on the extended linear sigma model with nucleon degrees of freedom. It is shown that there are three types of phase transitions in nuclear matter: the chiral symmetry nonrestoration (SNR) at high temperature, the well-known liquid–gas (LG) phase transition at sub-saturation density and the Lifshitz phase transition (LPT) from the fully-gapped state to the state with Fermi surface. Their phase diagrams are established in the (T, ?)-plane and their physical properties are investigated in detail. The relationship between the chiral phase transition and the LG phase transition in nuclear matter is discussed. (author)

445

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

446

...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

447

...In the Matter of Duke Energy Carolinas, LLC; (Oconee Nuclear Station, Units 1, 2...Modifying License I Duke Energy Carolinas, LLC (Duke...to the Licensee, Duke Energy Carolinas, LLC, Oconee Nuclear Station, 7800...

2013-07-10

448

Three flavor Nambu-Jona Lasinio model with Polyakov loop and competition with nuclear matter

We study the phase diagram of the three flavor Polyakov-Nambu-Jona Lasinio (PNJL) model and in particular the interplay between chiral symmetry restoration and deconfinement crossover. We compute chiral condensates, quark densities and the Polyakov loop at several values of temperature and chemical potential. Moreover we investigate on the role of the Polyakov loop dynamics in the transition from nuclear matter to quark matter.

Ciminale, M; Ippolito, N D; Nardulli, G; Ruggieri, M

2007-01-01

449

The main goal of this Thesis, is the study of the thermodynamic properties of strongly interacting and dense nuclear matter, away from the nuclear ground state. This analysis constitutes one of the most interesting aspect and one of the major tasks in the modern high-energy nuclear physics. The first part of this dissertation, addresses the phenomenological and theoretical study of the nuclear matter equation of state, under the extreme conditions reached in high energy heavy ion collision ex...

Pigato, Daniele

2013-01-01

450

International Nuclear Information System (INIS)

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.

451

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

452

International Nuclear Information System (INIS)

The Debye screening masses of the ?, ? and neutral ? mesons and the photon are calculated in the relativistic mean-field approximation. As the density of the nucleon increases, all the screening masses of mesons increase. A different result with Brown–Rho scaling is shown, which implies a reduction in the mass of all the mesons in the nuclear matter, except the pion. Replacing the masses of the mesons with their corresponding screening masses in the Walecka-1 model, five saturation properties of the nuclear matter are fixed reasonably, and then a density-dependent relativistic mean-field model is proposed without introducing the nonlinear self-coupling terms of mesons. (author)

453

The optical potential of an attractive nonrelativistic electron gas interacting with nuclear matter is determined on the basis of the concept of degenerate Fermi gas. In fact, the involved electrons are treated as three-dimensional quantum harmonic oscillators confined at the surface of a spherical (approximately ideal) potential well. Within this picture, the Fermi velocity is calculated as well as the spatial electron density at the surface of the potential well and the attractive force between the electron gas and the nuclear matter. In addition, considerations related to the Lippmann-Schwinger model are made.

Grado-Caffaro, M. A.; Grado-Caffaro, M.

2012-12-01

454

Analysis of the doubly heavy baryons in the nuclear matter with the QCD sum rules

In this article, we study the doubly heavy baryon states ? cc , ? cc , ? bb and ? bb in the nuclear matter using the QCD sum rules, and derive three coupled QCD sum rules for the masses, vector self-energies and pole residues. The predictions for the mass-shifts in the nuclear matter ? M_{\\varXi_{cc}}=-1.11 GeV, ? M_{\\varOmega_{cc}}=-0.33 GeV, ? M_{\\varXi_{bb}}=-3.37 GeV and ? M_{\\varOmega_{bb}}=-1.05 GeV can be confronted with experimental data in the future.

Wang, Zhi-Gang

2012-08-01

455

Cluster Formation and The Virial Equation of State of Low-Density Nuclear Matter

We present the virial equation of state of low-density nuclear matter composed of neutrons, protons and alpha particles. The virial equation of state is model-independent, and therefore sets a benchmark for all nuclear equations of state at low densities. We calculate the second virial coefficients for nucleon-nucleon, nucleon-alpha and alpha-alpha interactions directly from the relevant binding energies and scattering phase shifts. The virial approach systematically takes into account contributions from bound nuclei and the resonant continuum, and consequently provides a framework to include strong-interaction corrections to nuclear statistical equilibrium models. The virial coefficients are used to make model-independent predictions for a variety of properties of nuclear matter over a range of densities, temperatures and compositions. Our results provide important constraints on the physics of the neutrinosphere in supernovae. The resulting alpha particle concentration differs from all equations of state cu...

Horowitz, C J

2006-01-01

456

A possible determination of the quark radiation length in cold nuclear matter

Energy Technology Data Exchange (ETDEWEB)

We calculate the differential Drell-Yan production cross section in proton-nucleus collisions by including both next-to-leading order perturbative effects and effects of the nuclear medium. We demonstrate that dilepton production in fixed target experiments is an excellent tool to study initial-state parton energy loss in large nuclei and to accurately determine the stopping power of cold nuclear matter. We provide theoretical predictions for the attenuation of the Drell-Yan cross section at large values of Feynman x{sub F} and show that for low proton beam energies experimental measurements at Fermilab's E906 can clearly distinguish between nuclear shadowing and energy loss effects. If confirmed by data, our results may help determine the quark radiation length in cold nuclear matter X{sub 0}{approx}10{sup -13} m.

Neufeld, R.B., E-mail: neufeld@lanl.gov [Los Alamos National Laboratory, Theoretical Division, Los Alamos, NM 87545 (United States); Vitev, Ivan, E-mail: ivitev@lanl.gov [Los Alamos National Laboratory, Theoretical Division, Los Alamos, NM 87545 (United States); Zhang Benwei, E-mail: bwzhang@iopp.ccnu.edu.cn [Key Laboratory of Quark and Lepton Physics (Huazhong Normal University), Ministry of Education (China); Los Alamos National Laboratory, Theoretical Division, Los Alamos, NM 87545 (United States)

2011-10-25

457

Three-dimensional calculation of inhomogeneous structure in low-density nuclear matter

In low-density nuclear matter which is relevant to the crust region of neutron stars and collapsing stage of supernovae, non-uniform structures called "nuclear pasta" are expected. So far, most works on nuclear pasta have used the Wigner-Seitz cell approximation with anzats about the geometrical structures like droplet, rod, slab and so on. We perform fully three-dimensional calculation of non-uniform nuclear matter for some cases with fixed proton ratios and in beta-equilibrium based on the relativistic mean-field model and the Thomas-Fermi approximation. In our calculation typical pasta structures are observed. However, there appears some difference in the density region of each pasta structure.

Okamoto, Minoru; Yabana, Kazuhiro; Tatsumi, Toshitaka

2011-01-01

458

A comparative study of statistical models for nuclear equation of state of stellar matter

We compare three different statistical models for the equation of state (EOS) of stellar matter at subnuclear densities and temperatures (0.5-10 MeV) expected to occur during the collapse of massive stars and supernova explosions. The models introduce the distributions of various nuclear species in nuclear statistical equilibrium, but use somewhat different nuclear physics inputs. It is demonstrated that the basic thermodynamical quantities of stellar matter under these conditions are similar, except in the region of high densities and low temperatures. We demonstrate that mass and isotopic distributions have considerable differences related to the different assumptions of the models on properties of nuclei at these stellar conditions. Overall, the three models give similar trends, but the details reflect the uncertainties related to the modelling of medium effects, such as the temperature and density dependence of surface and bulk energies of heavy nuclei, and the nuclear shell structure effects. In order to...

Buyukcizmeci, N; Mishustin, I N; Ogul, R; Hempel, M; Schaffner-Bielich, J; Thielemann, F -K; Furusawa, S; Sumiyoshi, K; Yamada, S; Suzuki, H

2012-01-01

459

Appearance of the single gyroid network phase in "nuclear pasta" matter

Nuclear matter under the conditions of a supernova explosion unfolds into a rich variety of spatially structured phases, called nuclear pasta. We investigate the role of periodic networklike structures with negatively curved interfaces in nuclear pasta structures, by static and dynamic Hartree-Fock simulations in periodic lattices. As the most prominent result, we identify for the first time the single gyroid network structure of cubic chiral I 4123 symmetry, a well-known configuration in nanostructured soft-matter systems, both as a dynamical state and as a cooled static solution. Single gyroid structures form spontaneously in the course of the dynamical simulations. Most of them are isomeric states. The very small energy differences from the ground state indicate its relevance for structures in nuclear pasta.

Schuetrumpf, B.; Klatt, M. A.; Iida, K.; Schröder-Turk, G. E.; Maruhn, J. A.; Mecke, K.; Reinhard, P.-G.

2015-02-01

460

Weak response of nuclear matter at low momentum transfer

Energy Technology Data Exchange (ETDEWEB)

A quantitative understanding of the weak nuclear response is a prerequisite for the computer simulations of astrophysical phenomena like supernovae explosions and neutron star cooling. In order to reduce the systematic uncertainties associated with the simulations, a consistent framework, able to take into account dynamical correlation effects, is needed to compute neutrino-nucleon and neutrino-nucleus reaction rates. In this paper we describe the many-body theory of the weak nuclear response at low energy regime. We show how to include both short and long range correlations effects in a consistent fashion.

Farina, Nicola, E-mail: nicola.farina@roma1.infn.i [INFN, Sezione di Roma. I-00185 Roma (Italy)

2009-05-01

461

Weak response of nuclear matter at low momentum transfer

International Nuclear Information System (INIS)

A quantitative understanding of the weak nuclear response is a prerequisite for the computer simulations of astrophysical phenomena like supernovae explosions and neutron star cooling. In order to reduce the systematic uncertainties associated with the simulations, a consistent framework, able to take into account dynamical correlation effects, is needed to compute neutrino-nucleon and neutrino-nucleus reaction rates. In this paper we describe the many-body theory of the weak nuclear response at low energy regime. We show how to include both short and long range correlations effects in a consistent fashion.

462

Neutrino Bremsstrahlung in Neutron Matter from Effective Nuclear Interactions

We revisit the emissivity from neutrino pair bremsstrahlung in neutron-neutron scattering, nn -> nn nu nubar, which was calculated from the one-pion exchange potential including correlation effects by Friman and Maxwell. Starting from the free-space low-momentum nucleon-nucleon interaction V_{low k}, we include tensor, spin-orbit and second-order medium-induced non-central contributions to the scattering amplitude in neutron matter. We find that the screening of the nucleon-...

Schwenk, A.; Jaikumar, P.; Gale, C.

2003-01-01

463

Observing compact quark matter droplets in relativistic nuclear collisions

Compactness is introduced as a new method to search for the onset of the quark matter transition in relativistic heavy ion collisions. That transition supposedly leads to stronger compression and higher compactness of the source in coordinate space. That effect could be observed via pion interferometry. We propose to measure the compactness of the source in the appropriate principal axis frame of the compactness tensor in coordinate space.

Paech, Kerstin; Lisa, M A; Dumitru, A; Stöcker, H; Greiner, W

2000-01-01

464

Effective field theory for lambda-sigma^0 mixing in nuclear matter

We extend the effective field theory approach which successfully describes ordinary nuclei and nuclear matter to incorporate strangeness in nuclear structure. Central object is a chiral effective Lagrangian involving the baryon octet, the Goldstone boson octet, the vector meson octet and a light scalar singlet. According to the rules of effective field theory, we include all interaction terms (up to a given order of truncation) that are consistent with the underlying symmetr...

Mueller, Horst

1998-01-01

465

New method of studying slow strange meson properties in nuclear matter

We suggest the new experimental method to explore the properties of slow strange mesons at normal nuclear matter density. We show that the $K^{+}$ and $K^{-}$ mesons with extremely small momenta relative to the surrounding medium rest frame can be produced in nucleus-nucleon collisions and their production cross sections are experimentally measurable. The experiments on study of the momentum dependence of meson-nuclear potentials are discussed.

Kiselev, Y T; Kiselev, Yu.T.

2003-01-01

466

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

International Nuclear Information System (INIS)

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

467

Spectral functions for relativistic models of nuclear matter

International Nuclear Information System (INIS)

We introduce a quick method to determine the spectral function for relativistic fermions with a given spinor structure of their self energy. The method is applied to include tensor parts of the self energy, which might be of importance in nuclear systems. (orig.)

468

Phenomenological effective interaction and the mean field in nuclear matter

International Nuclear Information System (INIS)

The density matrix expansion has been frequently used in various nuclear calculations for the advantage of obtaining analytical expressions and simpler calculational procedure. The purpose of the present work is to outline a comparison of the density matrix expansion (DME) approximation with the actual momentum and density dependence of the mean field

469

Multiple two-body scattering inside nuclear matter

International Nuclear Information System (INIS)

The momentum distributions resulting from multiple N-N collisions inside an excited nucleus and their importance in nuclear reaction cross-sections are discussed. A general expression for single scattering between nucleon moving through an excited nucleus and a target nucleon is obtained. It is, then extended to multiple two-body interactions inside an excited nucleus. (M.G.B.)

470

Non-Abelian behavior of ? bosons in cold symmetric nuclear matter

International Nuclear Information System (INIS)

The ground-state energy of infinite symmetric nuclear matter is usually described by strongly interacting nucleons obeying the Pauli exclusion principle. We can imagine a unitary transformation which groups four nonidentical nucleons (i.e., with different spin and isospin) close in coordinate space. Those nucleons, being nonidentical, do not obey the Pauli principle, thus their relative momenta are negligibly small (just to fulfill the Heisenberg principle). Such a cluster can be identified with an ? boson. But in dense nuclear matter, those ? particles still obey the Pauli principle since are constituted of fermions. The ground state energy of nuclear matter ? clusters is the same as for nucleons, thus it is degenerate. We could think of ? particles as vortices which can now braid, for instance making 8Be which leave the ground state energy unchanged. Further braiding to heavier clusters (12C, 16O,...) could give a different representation of the ground state at no energy cost. In contrast d-like clusters (i.e., N=Z odd-odd nuclei, where N and Z are the neutron and proton number, respectively) cannot describe the ground state of nuclear matter and can be formed at high excitation energies (or temperatures) only. We show that even-even, N=Z, clusters could be classified as non-Abelian states of matter. As a consequence an ? condensate in nuclear matter might be hindered by the Fermi motion, while it could be possible a condensate le it could be possible a condensate of 8Be or heavier clusters.

471

Halftime - a balance in matters nuclear of the grand coalition

International Nuclear Information System (INIS)

On November 11, 2005, the coalition partners, CDU/CSU and SPD, signed the agreement establishing a coalition in the German federal parliament under the heading of ''Together for Germany''. Among other things, this raised the question of what would happen in the fields of energy policy and nuclear power. After 2 years of a grand coalition, it is time to draw some interim conclusions. The coalition agreement contains statements to the effect that energy policy means fundamental economic, structural and climate policies, and that secure, low-cost, non-polluting energy supplies are elementary prerequisites of a modern, capable national economy. A sustainable overall energy policy concept should be based on a balanced energy mix. This overall concept, one of the results of ''energy summit'' talks with Federal Chancellor Merkel, was announced for the end of 2007. The 3 energy summit discussions with Federal Chancellor Merkel deliberately avoided the subject of nuclear power. There is no debate about the implications of nuclear energy. This in no way improved the status of nuclear power in Germany. What remains is hope for the second half of this government's term of office. The beginning of that term is marked by the McKinsey study, initiated by the Federation of German Industries (BDI), on ''Cost and Potential of Avoiding Greenhouse Gas Emissions in Germany,'' which says that operating German nuclear power plants for 60 or even 45 years would result in a CO2 avoidance poteyears would result in a CO2 avoidance potential for 2020 which would be approximately 90 million tons higher, and in avoidance costs lower by 4.5 billion euro per year. (orig.)

472

Microscopic calculations and energy expansions for neutron-rich matter

We investigate asymmetric nuclear matter with two- and three-nucleon interactions based on chiral effective field theory, where three-body forces are fit only to light nuclei. Focusing on neutron-rich matter, we calculate the energy for different proton fractions and include estimates of the theoretical uncertainty. We use our ab-initio results to test the quadratic expansion around symmetric matter with the symmetry energy term, and confirm its validity for highly asymmetric systems. Our calculations are in remarkable agreement with an empirical parametrization for the energy density. These findings are very useful for astrophysical applications and for developing new equations of state.

Drischler, C; Schwenk, A

2013-01-01

473

In this contribution, we review the most important physics presented originally in our recent publications. Some new analyses, insights and perspectives are also provided. We showed recently that the symmetry energy $E_{sym}(\\rho)$ and its density slope $L(\\rho)$ at an arbitrary density $\\rho$ can be expressed analytically in terms of the magnitude and momentum dependence of the single-nucleon potentials using the Hugenholtz-Van Hove (HVH) theorem. These relationships provide new insights about the fundamental physics governing the density dependence of nuclear symmetry energy. Using the isospin and momentum (k) dependent MDI interaction as an example, the contribution of different terms in the single-nucleon potential to the $E_{sym}(\\rho)$ and $L(\\rho)$ are analyzed in detail at different densities. It is shown that the behavior of $E_{sym}(\\rho)$ is mainly determined by the first-order symmetry potential $U_{sym,1}(\\rho,k)$ of the single-nucleon potential. The density slope $L(\\rho)$ depends not only on th...

Xu, Chang; Chen, Lie-Wen

2013-01-01

474

Exploring medium effects on the nuclear force

International Nuclear Information System (INIS)

This STI product contains a description of results from theoretical studies in nuclear physics. The goal is a systematic investigation of the nuclear force in the nuclear medium. The problems addressed are: density-dependent effective interactions as seen through proton-nucleus reactions, nuclear matter with unequal densities of protons and neutrons, applications to asymmetric nuclei through predictions of neutron radii and neutron skins