Incompressibility of asymmetric nuclear matter
International Nuclear Information System (INIS)
Using an isospin- and momentum-dependent modified Gogny (MDI) interaction, the Skyrme-Hartree-Fock (SHF) approach, and a phenomenological modified Skyrme-like (MSL) model, we have studied the incompressibility Ksat(δ) of isospin asymmetric nuclear matter at its saturation density. Our results show that in the expansion of Ksat(δ) in powers of isospin asymmetry δ, i.e., Ksat(δ) = K0 + Ksat,2δ2 + Ksat,4δ4 + O(δ6), the magnitude of the 4th-order Ksat,4 parameter is generally small. The 2nd-order Ksat,2 parameter thus essentially characterizes the isospin dependence of the incompressibility of asymmetric nuclear matter at saturation density. Furthermore, the Ksat,2 can be expressed as Ksat,2 = Ksym – 6L – J0/K0 L in terms of the slope parameter L and the curvature parameter Ksym of the symmetry energy and the third-order derivative parameter J0 of the energy of symmetric nuclear matter at saturation density, and we find the higher order J0 contribution to Ksat,2 generally cannot be neglected. Also, we have found a linear correlation between Ksym and L as well as between J0/K0 and K0. Using these correlations together with the empirical constraints on K0 and L, the nuclear symmetry energy Esym(ρ0) at normal nuclear density, and the nucleon effective mass, we have obtained an estimated value of Ksat,2 = -370 ± 120 MeV for the 2nd-order parameter in the isospin asymmetry expansion of the incompressibility of asymmetric nuclear matter at its saturation density. (author)
Droplet formation in cold asymmetric nuclear matter
Menezes, D. P.; Providência, C.
1999-01-01
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.
Medium polarization in asymmetric nuclear matter
Zhang, S. S.; Cao, L. G.; U. Lombardo(INFN-LNS Catania, Italy); P. Schuck(IPN Grenoble, France)
2016-01-01
The influence of the core polarization on the effective nuclear interaction of asymmetric nuclear matter is calculated in the framework of the induced interaction theory. The strong isospin dependence of the density and spin density fluctuations is studied along with the interplay between the neutron and proton core polarizations. Moving from symmetric nuclear matter to pure neutron matter the crossover of the induced interaction from attractive to repulsive in the spin singlet state is deter...
Asymmetric nuclear matter equation of state
International Nuclear Information System (INIS)
Systematic calculations of asymmetric nuclear matter have been performed in the framework of the Brueckner-Bethe-Goldstone approach in a wide range of both density and asymmetry parameter. The empirical parabolic law fulfilled by the binding energy per nucleon is confirmed by the present results in all the range of the asymmetry parameter values. The predominant role of the 3S1-3D1 component of the NN interaction is elucidated. A linear variation of the proton and neutron single-particle potentials is found as increasing the neutron excess; a deviation from the phenomenological potentials occurs for highly asymmetric matter as an effect of the self-consistency. The present calculations of the incompressibility predict a strong softening of the equation of state going from symmetric to asymmetric nuclear matter. The proton fraction in equilibrium with neutron matter has been determined from the beta-stability condition and its relevance to the superfluidity of neutron stars has been investigated
Kaons and antikaons in asymmetric nuclear matter
Mishra, A; Greiner, W
2008-01-01
The properties of kaons and antikaons and their modification in isospin asymmetric nuclear matter are investigated using a chiral SU(3) model. These isospin dependent medium effects are important for asymmetric heavy ion collision experiments. In the present work, the medium modifications of the energies of the kaons and antikaons, within the asymmetric nuclear matter, arise due to the interactions of kaons and antikaons with the nucleons and scalar mesons. The values of the parameters in the model are obtained by fitting the saturation properties of nuclear matter and kaon-nucleon scattering lengths. The pion-nucleon scattering lengths are also calculated within the chiral effective model and compared with earlier results from the literature. The density dependence of the isospin asymmetry is seen to be appreciable for the kaon and antikaon optical potentials. This can be particularly relevant for the future accelerator facility FAIR at GSI, where experiments using neutron rich beams are planned to be used i...
Hot and flowing, asymmetric nuclear matter
International Nuclear Information System (INIS)
We develop a consistent treatment for hot and flowing asymmetric nuclear matter. Using the mean-field theory, predictions of the σ- ω Walecka model at finite temperature are compared with the corresponding results of the Zimanyi-Moszlowski and the non-linear models. The statistical theory of grand-canonical potentials is incorporated to the formalism. We also describe the behavior, at finite temperature, of the asymmetric and flowing nuclear matter. As an application, we describe bulk properties of neutron and protoneutron stars by considering the Tolman-Oppenheimer-Volkoff equations. (author)
Vacuum fluctuation effects on asymmetric nuclear matter
Guo, X.-H.; Liu, B.(Center for High Energy Physics, Tsinghua University, Beijing, China); Weng, M. -H.
2009-01-01
The vacuum fluctuation (VF) effects on asymmetric nuclear matter are investigated. Masses of nucleons and mesons are modified in the nuclear medium by calculating the loop-diagram corrections and the density dependence of hadron masses is obtained. The relativistic Lagrangian density with the isovector scalar $\\delta$ meson is used to calculate the nuclear equation of state (EOS) in the framework of the relativistic mean-field (RMF) approach, the effects of the in-medium hadron masses on the ...
Magnetic properties of strongly asymmetric nuclear matter
International Nuclear Information System (INIS)
We investigate stability of neutron matter containing a small proton admixture with respect to spin fluctuations. We establish conditions under which strongly asymmetric nuclear matter could acquire a permanent magnetization. It is shown that if the protons are localized, the system becomes unstable to spin fluctuations for arbitrarily weak proton-neutron spin interactions. For non-localized protons there exists a threshold value of the spin interaction above which the system can develop a spontaneous polarization. 12 refs., 2 figs. (author)
Kaons and antikaons in asymmetric nuclear matter
Mishra, Amruta; Schramm, Stefan; Greiner, W.
2008-08-01
The properties of kaons and antikaons and their modifications in isospin asymmetric nuclear matter are investigated using a chiral SU(3) model. These isospin-dependent medium effects are important for asymmetric heavy-ion collision experiments and will be especially relevant for the neutron-rich heavy-ion collision experiments in the future accelerator facility GSI Facility for Antiproton and Ion Research (GSI-FAIR). In the present work, the medium modifications of the energies of the kaons and antikaons, within the asymmetric nuclear matter, arise because of the interactions of kaons and antikaons with the nucleons and scalar mesons. The values of the parameters in the model are obtained by fitting the saturation properties of nuclear matter and kaon-nucleon scattering lengths for I=0 and I=1 channels. Furthermore, the isovector and isoscalar pion-nucleon scattering lengths are calculated within the chiral effective model and compared with earlier results from the literature. The kaon-nucleon and pion-nucleon Σ coefficients are also calculated within the present chiral SU(3) model.
Medium polarization in asymmetric nuclear matter
Zhang, S S; Lombardo, U; Schuck, P
2016-01-01
The influence of the core polarization on the effective nuclear interaction of asymmetric nuclear matter is calculated in the framework of the induced interaction theory. The strong isospin dependence of the density and spin density fluctuations is studied along with the interplay between the neutron and proton core polarizations. Moving from symmetric nuclear matter to pure neutron matter the crossover of the induced interaction from attractive to repulsive in the spin singlet state is determined as a function of the isospin imbalance.The density range in which it occurs is also determined. For the spin triplet state the induced interaction turns out to be always repulsive. The implications of the results for the neutron star superfluid phases are shortly discussed.
Phase transitions in warm, asymmetric nuclear matter
International Nuclear Information System (INIS)
A relativistic mean-field model of nuclear matter with arbitrary proton fraction is studied at finite temperature. An analysis is performed of the liquid-gas phase transition in a system with two conserved charges (baryon number and isospin) using the stability conditions on the free energy, the conservation laws, and Gibbs' criteria for phase equilibrium. For a binary system with two phases, the coexistence surface (binodal) is two dimensional. The Maxwell construction through the phase-separation region is discussed, and it is shown that the stable configuration can be determined uniquely at every density. Moreover, because of the greater dimensionality of the binodal surface, the liquid-gas phase transition is continuous (second order by Ehrenfest's definition), rather than discontinuous (first order), as in familiar one-component systems. Using a mean-field equation of state calibrated to the properties of nuclear matter and finite nuclei, various phase-separation scenarios are considered. The model is then applied to the liquid-gas phase transition that may occur in the warm, dilute matter produced in energetic heavy-ion collisions. In asymmetric matter, instabilities that produce a liquid-gas phase separation arise from fluctuations in the proton concentration (chemical instability), rather than from fluctuations in the baryon density (mechanical instability)
G. H. Bordbar; M. Bigdeli
2008-01-01
In this paper, we calculate properties of the spin polarized asymmetrical nuclear matter and neutron star matter, using the lowest order constrained variational (LOCV) method with the $AV_{18}$, $Reid93$, $UV_{14}$ and $AV_{14}$ potentials. According to our results, the spontaneous phase transition to a ferromagnetic state in the asymmetrical nuclear matter as well as neutron star matter do not occur.
G. H. Bordbar
2003-01-01
We have studied the influences of isospin symmetry breaking of nucleon-nucleon interaction on the various properties of asymmetrical nuclear matter and $\\beta$-stable matter. For asymmetrical nuclear matter, it is found that by including this isospin symmetry breaking, the changes of bulk properties increase by increasing both density and asymmetry parameter. However, these effects on the total energy and equation of state of $\\beta$-stable matter are ignorable. For asymmetrical nuclear matte...
Phase transitions in warm, asymmetric nuclear matter
Müller, H; Mueller, Horst; Serot, Brian D
1995-01-01
A relativistic mean-field model of nuclear matter with arbitrary proton fraction is studied at finite temperature. An analysis is performed of the liquid-gas phase transition in a system with two conserved charges (baryon number and isospin) using the stability conditions on the free energy, the conservation laws, and Gibbs' criteria for phase equilibrium. For a binary system with two phases, the coexistence surface (binodal) is two-dimensional. The Maxwell construction through the phase-separation region is discussed, and it is shown that the stable configuration can be determined uniquely at every density. Moreover, because of the greater dimensionality of the binodal surface, the liquid-gas phase transition is continuous (second order by Ehrenfest's definition), rather than discontinuous (first order), as in familiar one-component systems. Using a mean-field equation of state calibrated to the properties of nuclear matter and finite nuclei, various phase-separation scenarios are considered. The model is th...
Asymmetric nuclear matter : A variational approach with reid93 interaction
International Nuclear Information System (INIS)
Calculation of asymmetric nuclear matter have been performed in the frame work of the lowest order constrained variational method (LOCV) approach in a wide range of both density and asymmetry parameter. The new charge independent breaking Reid potential (Ried39) used for calculating the equation of state of this system. It is shown that the empirical parabolic law of the binding energy per nucleon is fulfilled in the whole asymmetric range up to high densities. The results compared with the others many body calculations
Pairing effects on spinodal decomposition of asymmetric nuclear matter
Directory of Open Access Journals (Sweden)
Burrello S.
2015-01-01
Full Text Available We present an analysis framed in the general context of two-component fermionic systems subjected to pairing correlations. The study is conducted for unstable asymmetric nuclear matter at low temperature, along the clusterization process driven by spinodal instabilities. It is shown that, especially around the transition temperature from the superfluid to the normal phase, pairing correlations may have non-negligible effects on the isotopic features of the clusterized low-density matter, which could be of interest also in the astrophysical context.
Asymmetric nuclear matter: The role of the isovector scalar channel
International Nuclear Information System (INIS)
We try to single out some qualitative effects of coupling to a δ-isovector-scalar meson, introduced in a minimal way in a phenomenological hadronic field theory. Results for the equation of state (EOS) and the phase diagram of asymmetric nuclear matter (ANM) are discussed. We stress the consistency of the δ-coupling introduction in a relativistic approach. Contributions to the slope and curvature of the symmetry energy and to the neutron-proton effective mass splitting appear particularly interesting. A more repulsive EOS for neutron matter at high baryon densities is expected. Effects on the critical properties of warm ANM, mixing mechanical and chemical instabilities and isospin distillation, are also presented. The δ influence is mostly on the isovectorlike collective response. The results are largely analytical, and this makes the physical meaning quite transparent. Implications for nuclear structure properties of drip-line nuclei and for reaction dynamics with radioactive beams are finally pointed out
AMD study of the EOS of asymmetric nuclear matter in nuclear collisions
International Nuclear Information System (INIS)
The effects of the equation of state of asymmetric nuclear matter on the nuclear collisions are discussed based on the microscopic calculations by antisymmetrized molecular dynamics. In the calculations with the different effective interactions corresponding to different density dependence of the symmetry energy, the isospin effects in high and low density stages are seen in the collisions of neutron-rich unstable nuclei as well as in collisions of heavy stable nuclei with large N/Z. (author)
Nuclear symmetry energy effects on liquid-gas phase transition in hot asymmetric nuclear matter
Bharat K. Sharma; Pal, Subrata
2010-01-01
The liquid-gas phase transition in hot asymmetric nuclear matter is investigated within relativistic mean-field model using the density dependence of nuclear symmetry energy constrained from the measured neutron skin thickness of finite nuclei. We find symmetry energy has a significant influence on several features of liquid-gas phase transition. The boundary and area of the liquid-gas coexistence region, the maximal isospin asymmetry and the critical values of pressure and isospin asymmetry ...
Thermodynamic instabilities in warm and dense asymmetric nuclear matter and in compact stars
Pigato, Daniele; Lavagno, Andrea
2016-01-01
We investigate the possible thermodynamic instability in a warm and dense nuclear medium where a phase transition from nucleonic matter to resonance-dominated Δ-matter can take place. Such a phase transition is characterized by both mechanical instability (fluctuations on the baryon density) and by chemical-diffusive instability (fluctuations on the isospin concentration) in asymmetric nuclear matter. Similarly to the liquid-gas phase transition, the nucleonic and the Δ-matter phase have a di...
A study on the thermodynamics of liquid-gas phase transition for asymmetric polarized nuclear matter
International Nuclear Information System (INIS)
The equation of state, developed before, for asymmetric polarized nuclear matter revealed a liquid-gas phase transition behaviour. Such transition is typical to that described by Van der Waal equation of real gas. In the present work, the analogy between nuclear matter and real macroscopic gas is examined. The nuclear matter equation of state is compared to Van der Waal equation to find the corresponding values of the real gas constants. Results are analysed in terms of the physical meanings of such constants. The latent heat of vaporization and entropy of transformation are calculated for symmetric nuclear matter. The critical point data and Van der Waal constants are estimated for asymmetric polarized nuclear matter. (author). 17 refs, 9 figs, 4 tabs
Cavitation and bubble collapse in hot asymmetric nuclear matter
Kolomietz, V M
2004-01-01
The dynamics of embryonic bubbles in overheated, viscous and non-Markovian nuclear matter is studied. We show that the memory and the Fermi surface distortions significantly affect the hinderance of bubble collapse and determine a characteristic oscillations of the bubble radius. These oscillations occur due to the additional elastic force induced by the memory integral.
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.
Nucleon mean free path in asymmetric nuclear matter at finite temperature
International Nuclear Information System (INIS)
The nucleon mean free path in symmetric and asymmetric nuclear matter is investigated in the framework of the finite temperature Brueckner theory. The realistic Bonn B two-body nucleon–nucleon interaction in combination with a consistent microscopic three-body force is adopted in the calculations. The results of the nucleon mean free path at zero temperature are in good agreement with the experimental data. The temperature and density and isospin dependence of the mean free path are studied systematically in asymmetric nuclear matter. (paper)
Graesser, Michael L.; Shoemaker, Ian M.; Vecchi, Luca
2011-01-01
In existing dark matter models with global symmetries the relic abundance of dark matter is either equal to that of anti-dark matter (thermal WIMP), or vastly larger, with essentially no remaining anti-dark matter (asymmetric dark matter). By exploring the consequences of a primordial asymmetry on the coupled dark matter and anti-dark matter Boltzmann equations we find large regions of parameter space that interpolate between these two extremes. Interestingly, this new asymmetric WIMP framewo...
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)
Thermodynamic instabilities in warm and dense asymmetric nuclear matter and in compact stars
Lavagno, A.; Gervino, G.; Pigato, D.
2016-01-01
We investigate the possible thermodynamic instability in a warm and dense nuclear medium where a phase transition from nucleonic matter to resonance-dominated Δ-matter can take place. Such a phase transition is characterized by both mechanical instability (fluctuations on the baryon density) and by chemical-diffusive instability (fluctuations on the isospin concentration) in asymmetric nuclear matter. Similarly to the liquid-gas phase transition, the nucleonic and the Δ-matter phase have a different isospin density in the mixed phase. In the liquid-gas phase transition, the process of producing a larger neutron excess in the gas phase is referred to as isospin fractionation. A similar effects can occur in the nucleon- Δmatter phase transition due essentially to a Δ- excess in the Δ-matter phase in asymmetric nuclear matter. In this context we also discuss the relevance of Δ-isobar degrees of freedom in the bulk properties and in the maximum mass of compact stars.
Variational Calculation for the Equation of State of Hot Asymmetric Nuclear Matter
International Nuclear Information System (INIS)
We calculate the equation of state (EOS) of asymmetric nuclear matter at finite temperatures with the cluster variational method based on the realistic nuclear Hamiltonian composed of the AV18 and UIX nuclear potentials. The free energy is calculated with an extension of the variational method proposed by Schmidt and Pandharipande. The obtained thermodynamic quantities such as entropy, internal energy, pressure and chemical potential derived from the free energy are reasonable. It is also found that the present variational calculation is self-consistent. These thermodynamic quantities are essential ingredients in our project for constructing a new nuclear EOS applicable to supernova simulations.
Coexistence of phases in asymmetric nuclear matter under strong magnetic fields
Aguirre, R
2014-01-01
The equation of state of nuclear matter is strongly affected by the presence of a magnetic field. Here we study the equilibrium configuration of asymmetric nuclear matter for a wide range of densities, isospin composition, temperatures and magnetic fields. Special attention is paid to the low density and low temperature domain, where a thermodynamical instability exists. Neglecting fluctuations of the Coulomb force, a coexistence of phases is found under such conditions, even for extreme magnetic intensities. We describe the nuclear interaction by using the non--relativistic Skyrme potential model within a Hartree--Fock approach. We found that the coexistence of phases modifies the equilibrium configuration, masking most of the manifestations of the spin polarized matter. However, the compressibility and the magnetic susceptibility show clear signals of this fact. Thermal effects are significative for both quantities, mainly out of the coexistence region.
Neutron optical potentials in unstable nuclei and the equation of state of asymmetric nuclear matter
International Nuclear Information System (INIS)
Neutron single particle potential is one of the basic macroscopic properties to describe structure and reactions of nuclei in nuclear reactors and in the universe. However, the potential is quite uncertain for unstable nuclei primarily because the equation of state (EOS) of asymmetric nuclear matter is not known well. The present authors studied systematically the empirical EOS of asymmetric nuclear matter using a macroscopic nuclear model; about two hundred EOS's having empirically allowed values of L (symmetry energy density derivative coefficient) and K0 (incompressibility) were obtained from the fittings to masses and radii of stable nuclei. It was suggested that the L value could be determined from global (Z, A) dependence of nuclear radii. In the present study, the single particle potential is examined assuming kinetic energies of non-interacting Fermi gases. The potential in a nucleus can be calculated easily, once the density distribution is solved using the effective nuclear interaction (EOS). Neutron and proton single particle potentials are calculated systematically for 80Ni using the two hundred EOS's. It is found that the neutron-proton potential difference has clear and appreciable L dependence, while the potential for each species does not show such simple dependence on L. (author)
Asymmetric nuclear matter in a parity doublet model with hidden local symmetry
Motohiro, Yuichi; Harada, Masayasu
2015-01-01
We construct a model to describe dense hadronic matter at zero and finite temperature, based on the parity doublet model of DeTar and Kunihiro, with including the iso-singlet scalar meson $\\sigma$ as well as $\\rho$ and $\\omega$ mesons. We show that, by including a six-point interaction of $\\sigma$ meson, the model reasonably reproduces the properties of the normal nuclear matter with the chiral invariant nucleon mass $m_0$ in the range from $500~{\\rm MeV}$ to $900~{\\rm MeV}$. Furthermore, we study the phase diagram based on the model, which shows that the value of the chiral condensate drops at the liquid-gas phase transition point and at the chiral phase transition point. We also study asymmetric nuclear matter and find that the first order phase transition for the liquid-gas phase transition disappears in asymmetric matter and that the critical density for the chiral phase transition at non-zero density becomes smaller for larger asymmetry.
RABHI, A; Pérez-García, M.A.; Providência, C.; Vidaña, I.
2014-01-01
We study the effect of a strong magnetic field on the proton and neutron spin polarization and magnetic susceptibility of asymmetric nuclear matter within a relativistic mean-field approach. It is shown that magnetic fields $B \\sim 10^{16} - 10^{17}$ G have already noticeable effects on the range of densities of interest for the study of the crust of a neutron star. Although the proton susceptibility is larger for weaker fields, the neutron susceptibility becomes of the same order or even lar...
Asymmetric nuclear matter based on chiral two- and three-nucleon interactions
Drischler, C.; Hebeler, K.; Schwenk, A.
2016-05-01
We calculate the properties of isospin-asymmetric nuclear matter based on chiral nucleon-nucleon (NN) and three-nucleon (3N) interactions. To this end, we develop an improved normal-ordering framework that allows us to include general 3N interactions starting from a plane-wave partial-wave-decomposed form. We present results for the energy per particle for general isospin asymmetries based on a set of different Hamiltonians, study their saturation properties, the incompressibility, symmetry energy, and also provide an analytic parametrization for the energy per particle as a function of density and isospin asymmetry.
Studies of the equation of state of asymmetric nuclear matter with R3B at FAIR
Lemmon R.
2012-01-01
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 detector...
Studies of the equation of state of asymmetric nuclear matter with R3B at FAIR
Directory of Open Access Journals (Sweden)
Lemmon R.
2012-07-01
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.
Thermodynamic instabilities in dense asymmetric nuclear matter and in compact stars
International Nuclear Information System (INIS)
We investigate the presence of thermodynamic instabilities in compressed asymmetric baryonic matter, reachable in high energy heavy ion collisions, and in the cold β-stable compact stars. To this end we study the relativistic nuclear equation of state with the inclusion of Δ-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 Δ− 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.
Finite size effects in liquid-gas phase transition of asymmetric nuclear matter
International Nuclear Information System (INIS)
Full text: Since the nuclear equation of state has been studied in astrophysical context as an element of neutron star or super-nova theories - a call for an evidence was produced in experimental nuclear physics. Heavy-ion collisions became a tool of study on thermodynamic properties of nuclear matter. A particular interest has been inspired here by critical behavior of nuclear systems, as a phase transition of liquid-gas type. A lot of efforts was put to obtain an experimental evidence of such a phenomenon in heavy-ion collisions. With the use of radioactive beams and high performance identification systems in a near future it will be possible to extend experimental investigation to asymmetric nuclear systems, where neutron-to-proton ratio is far from the stability line. This experimental development needs a corresponding extension of theoretical studies. To obtain a complete theory of the liquid-gas phase transition in small nuclear systems, produced in violent heavy-ion collisions, one should take into account two facts. First, that the nuclear matter forming nuclei is composed of protons and neutrons; this complicates the formalism of phase transitions because one has to deal with two separate, proton and neutron, densities and chemical potentials. The second and more important is that the surface effects are very strong in a system composed of a few hundreds of nucleons. This point is especially difficult to hold, because surface becomes an additional, independent state parameter, depending strongly on the geometrical configuration of the system, and introducing a non-local term in the equation of state. In this presentation we follow the recent calculation by Lee and Mekjian on the finite-size effects in small (A = 102 -103) asymmetric nuclear systems. A zero-range isospin-dependent Skyrme force is used to obtain a density and isospin dependent potential. The potential is then completed by additional terms giving contributions from surface and Coulomb energies. Taking into account the particle number conservation and assuming a specific geometrical configuration we introduce different and more precise formulae for these terms, keeping the main idea presented in unchanged. Applying a mean-field theory of nuclear matter, pressure and chemical potentials are obtained and used to resolve Gibbs conditions, giving properties of gas and liquid phases. (Author)
Saturation properties of asymmetric nuclear matter to be obtained from unstable nuclei
International Nuclear Information System (INIS)
We examine relations among the parameters characterizing the phenomenological equation of state (EOS) of nearly symmetric, uniform nuclear matter near the saturation density from experimental data on radii and masses of stable nuclei. The EOS parameters of interest are the symmetry energy S0, the symmetry energy density-derivative coefficient L and the incompressibility K0 at the normal nuclear density. The calculations of the nuclear properties were performed with a simplified Thomas-Fermi model. We find a constraint on (K0, 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 S0 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 (K0, 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 K0, and that systematic detection of the radii of such nuclei will help to determine the L value. (author)
Rabhi, A; Providência, C; Vidaña, I
2014-01-01
We study the effect of a strong magnetic field on the proton and neutron spin polarization and magnetic susceptibility of asymmetric nuclear matter within a relativistic mean-field approach. It is shown that magnetic fields $B \\sim 10^{16} - 10^{17}$ G have already noticeable effects on the range of densities of interest for the study of the crust of a neutron star. Although the proton susceptibility is larger for weaker fields, the neutron susceptibility becomes of the same order or even larger for small proton fractions and subsaturation densities for $B > 10^{16}$ G. We expect that neutron superfluidity in the crust will be affected by the presence of magnetic fields.
Minimal asymmetric dark matter
Boucenna, Sofiane M.; Martin B. Krauss; Enrico Nardi
2016-01-01
In the early Universe, any particle carrying a conserved quantum number and in chemical equilibrium with the thermal bath will unavoidably inherit a particle-antiparticle asymmetry. A new particle of this type, if stable, would represent a candidate for asymmetric dark matter (DM) with an asymmetry directly related to the baryon asymmetry. We study this possibility for a minimal DM sector constituted by just one (generic) $SU(2)_L$ multiplet $\\chi$ carrying hypercharge, assuming that at tempe...
Energy Technology Data Exchange (ETDEWEB)
Farina, Marco [Department of Physics, LEPP, Cornell University,Ithaca, NY, 14853 (United States)
2015-11-09
We study a natural implementation of Asymmetric Dark Matter in Twin Higgs models. The mirroring of the Standard Model strong sector suggests that a twin baryon with mass around 5 GeV is a natural Dark Matter candidate once a twin baryon number asymmetry comparable to the SM asymmetry is generated. We explore twin baryon Dark Matter in two different scenarios, one with minimal content in the twin sector and one with a complete copy of the SM, including a light twin photon. The essential requirements for successful thermal history are presented, and in doing so we address some of the cosmological issues common to many Twin Higgs models. The required interactions we introduce predict signatures at direct detection experiments and at the LHC.
International Nuclear Information System (INIS)
We study a natural implementation of Asymmetric Dark Matter in Twin Higgs models. The mirroring of the Standard Model strong sector suggests that a twin baryon with mass around 5 GeV is a natural Dark Matter candidate once a twin baryon number asymmetry comparable to the SM asymmetry is generated. We explore twin baryon Dark Matter in two different scenarios, one with minimal content in the twin sector and one with a complete copy of the SM, including a light twin photon. The essential requirements for successful thermal history are presented, and in doing so we address some of the cosmological issues common to many Twin Higgs models. The required interactions we introduce predict signatures at direct detection experiments and at the LHC
Asymmetric Dark Matter from Leptogenesis
Falkowski, Adam; Ruderman, Joshua T.; Volansky, Tomer
2011-01-01
We present a new realization of asymmetric dark matter in which the dark matter and lepton asymmetries are generated simultaneously through two-sector leptogenesis. The right-handed neutrinos couple both to the Standard Model and to a hidden sector where the dark matter resides. This framework explains the lepton asymmetry, dark matter abundance and neutrino masses all at once. In contrast to previous realizations of asymmetric dark matter, the model allows for a wide range of dark matter mas...
Annihilating Asymmetric Dark Matter
Bell, Nicole F; Shoemaker, Ian M
2014-01-01
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$\\%$.
Asymmetric dense matter in holographic QCD
Directory of Open Access Journals (Sweden)
Shin Ik Jae
2012-02-01
Full Text Available We study asymmetric dense matter in holographic QCD.We construct asymmetric dense matter by considering two quark flavor branes with dierent quark masses in a D4/D6/D6 model. To calculate the symmetry energy in nuclear matter, we consider two quarks with equal masses and observe that the symmetry energy increases with the total charge showing the stiff dependence. This behavior is universal in the sense that the result is independent of parameters in the model. We also study strange (or hyperon matter with one light and one intermediate mass quarks. In addition to the vacuum properties of asymmetric matter, we calculate meson masses in asymmetric dense matter and discuss our results in the light of in-medium kaon masses.
Minimal asymmetric dark matter
Boucenna, Sofiane M.; Krauss, Martin B.; Nardi, Enrico
2015-09-01
In the early Universe, any particle carrying a conserved quantum number and in chemical equilibrium with the thermal bath will unavoidably inherit a particle-antiparticle asymmetry. A new particle of this type, if stable, would represent a candidate for asymmetric dark matter (DM) with an asymmetry directly related to the baryon asymmetry. We study this possibility for a minimal DM sector constituted by just one (generic) SU (2)L multiplet χ carrying hypercharge, assuming that at temperatures above the electroweak phase transition an effective operator enforces chemical equilibrium between χ and the Higgs boson. We argue that limits from DM direct detection searches severely constrain this scenario, leaving as the only possibilities scalar or fermion multiplets with hypercharge y = 1, preferentially quintuplets or larger SU (2) representations, and with a mass in the few TeV range.
Minimal Asymmetric Dark Matter
Boucenna, Sofiane M; Nardi, Enrico
2015-01-01
In the early Universe, any particle carrying a conserved quantum number and in chemical equilibrium with the thermal bath will unavoidably inherit a particle-antiparticle asymmetry. A new particle of this type, if stable, would represent a candidate for asymmetric dark matter (DM) with an asymmetry directly related to the baryon asymmetry. We study this possibility for a minimal DM sector constituted by just one (generic) $SU(2)_L$ multiplet $\\chi$ carrying hypercharge, assuming that at temperatures above the electroweak phase transition an effective operator enforces chemical equilibrium between $\\chi$ and the Higgs boson. We argue that limits from DM direct detection searches severely constrain this scenario, ruling out the possibility of scalar multiplets, and leaving as the only possibilities fermion DM with hypercharge $y = 1/2$ and $y = 1$ with a mass in the few TeV range.
Isospin and momentum dependence of liquid-gas phase transition in hot asymmetric nuclear matter
International Nuclear Information System (INIS)
The liquid-gas phase transition in hot neutron-rich nuclear matter is investigated within a self-consistent thermal model using different interactions with or without isospin and/or momentum dependence. The boundary of the phase-coexistence region is shown to be sensitive to the density dependence of the nuclear symmetry energy as well as the isospin and momentum dependence of the nuclear interaction. (author)
Active Matter on Asymmetric Substrates
Reichhardt, C. J. Olson; Drocco, J.; Mai, T.; Wan, M. B.; Reichhardt, C.
2011-01-01
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 c...
Asymmetric dense matter in holographic QCD
Shin Ik Jae; Seo Yunseok; Kim Youngman; Sin Sang-Jin
2012-01-01
We study asymmetric dense matter in holographic QCD.We construct asymmetric dense matter by considering two quark flavor branes with dierent quark masses in a D4/D6/D6 model. To calculate the symmetry energy in nuclear matter, we consider two quarks with equal masses and observe that the symmetry energy increases with the total charge showing the stiff dependence. This behavior is universal in the sense that the result is independent of parameters in the model. We also study strange (or hyper...
Cluster formation in asymmetric nuclear matter: Semi-classical and quantal approaches
Energy Technology Data Exchange (ETDEWEB)
Ducoin, C. [Istituto Nazionale di Fisica Nucleare, Sezione di Catania, Via Santa Sofia 64, I-95123 Catania (Italy); LPC - IN2P3-CNRS/Ensicaen et Universite, F-14050 Caen cedex (France); GANIL (DSM-CEA/IN2P3-CNRS), B.P. 5027, F-14076 Caen cedex 5 (France)], E-mail: camille.ducoin@ct.infn.it; Margueron, J. [Institut de Physique Nucleaire, IN2P3-CNRS and Universite Paris-Sud, F-91406 Orsay cedex (France); Center for Mathematical Sciences, University of Aizu, Aizu-Wakamatsu, 965-8580 Fukushima (Japan); Chomaz, Ph. [GANIL (DSM-CEA/IN2P3-CNRS), B.P. 5027, F-14076 Caen cedex 5 (France)
2008-08-15
The nuclear-matter liquid-gas phase transition induces instabilities against finite-size density fluctuations. This has implications for both heavy-ion-collision and compact-star physics. In this paper, we study the clusterization properties of nuclear matter in a scenario of spinodal decomposition, comparing three different approaches: the quantal RPA, its semi-classical limit (Vlasov method), and a hydrodynamical framework. The predictions related to clusterization are qualitatively in good agreement varying the approach and the nuclear interaction. Nevertheless, it is shown that (i) the quantum effects reduce the instability zone, and disfavor short-wavelength fluctuations; (ii) large differences appear between the two semi-classical approaches, which correspond respectively to a collisionless (Vlasov) and local equilibrium description (hydrodynamics); (iii) the isospin-distillation effect is stronger in the local equilibrium framework; (iv) important variations between the predicted time-scales of cluster formation appear near the borders of the instability region.
Originally Asymmetric Dark Matter
Okada, Nobuchika; Seto, Osamu
2012-01-01
We propose a scenario with a fermion dark matter, where the dark matter particle used to be the Dirac fermion, but it takes the form of the Majorana fermion at a late time. The relic number density of the dark matter is determined by the dark matter asymmetry generated through the same mechanism as leptogenesis when the dark matter was the Dirac fermion. After efficient dark matter annihilation processes have frozen out, a phase transition of a scalar field takes place and generates Majorana ...
International Nuclear Information System (INIS)
We consider a simple class of models in which the relic density of dark matter is determined by the baryon asymmetry of the Universe. In these models a B-L asymmetry generated at high temperatures is transferred to the dark matter, which is charged under B-L. The interactions that transfer the asymmetry decouple at temperatures above the dark matter mass, freezing in a dark matter asymmetry of order the baryon asymmetry. This explains the observed relation between the baryon and dark matter densities for the dark matter mass in the range 5-15 GeV. The symmetric component of the dark matter can annihilate efficiently to light pseudoscalar Higgs particles a or via t-channel exchange of new scalar doublets. The first possibility allows for h0→aa decays, while the second predicts a light charged Higgs-like scalar decaying to τν. Direct detection can arise from Higgs exchange in the first model or a nonzero magnetic moment in the second. In supersymmetric models, the would-be lightest supersymmetric partner can decay into pairs of dark matter particles plus standard model particles, possibly with displaced vertices.
Asymmetric condensed dark matter
Aguirre, Anthony; Diez-Tejedor, Alberto
2016-04-01
We explore the viability of a boson dark matter candidate with an asymmetry between the number densities of particles and antiparticles. A simple thermal field theory analysis confirms that, under certain general conditions, this component would develop a Bose-Einstein condensate in the early universe that, for appropriate model parameters, could survive the ensuing cosmological evolution until now. The condensation of a dark matter component in equilibrium with the thermal plasma is a relativistic process, hence the amount of matter dictated by the charge asymmetry is complemented by a hot relic density frozen out at the time of decoupling. Contrary to the case of ordinary WIMPs, dark matter particles in a condensate must be lighter than a few tens of eV so that the density from thermal relics is not too large. Big-Bang nucleosynthesis constrains the temperature of decoupling to the scale of the QCD phase transition or above. This requires large dark matter-to-photon ratios and very weak interactions with standard model particles.
Sammarruca, Francesca
2013-01-01
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 importa...
Active matter on asymmetric substrates
Olson Reichhardt, C. J.; Drocco, J.; Mai, T.; Wan, M. B.; Reichhardt, C.
2011-10-01
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.
The deconfinement phase transition in asymmetric matter
International Nuclear Information System (INIS)
We study the phase transition of asymmetric hadronic matter to a quark-gluon plasma within the framework of a simple two-phase model. The analysis is performed in a system with two conserved charges (baryon number and isospin) using the stability conditions on the free energy, the conservation laws and Gibbs' criteria for phase equilibrium. The EOS is obtained in a separate description for the hadronic phase and for the quark-gluon plasma. For the hadrons, a relativistic mean-field model calibrated to the properties of nuclear matter is used, and a bag-model type EOS is used for the quarks and gluons. The model is applied to the deconfinement phase transition that may occur in matter created in ultra-relativistic collisions of heavy ions. Based on the two-dimensional coexistence surface (binodal), various phase separation scenarios and the Maxwell construction through the mixed phase are discussed. In the framework of the two-phase model the phase transition in asymmetric matter is continuous (second-order by Ehrenfest's definition) in contrast to the discontinuous (first-order) transition of symmetric systems. (orig.)
Twin Higgs Asymmetric Dark Matter.
García García, Isabel; Lasenby, Robert; March-Russell, John
2015-09-18
We study asymmetric dark matter (ADM) in the context of the minimal (fraternal) twin Higgs solution to the little hierarchy problem, with a twin sector with gauged SU(3)^{'}×SU(2)^{'}, a twin Higgs doublet, and only third-generation twin fermions. Naturalness requires the QCD^{'} scale Λ_{QCD}^{'}≃0.5-20 GeV, and that t^{'} is heavy. We focus on the light b^{'} quark regime, m_{b^{'}}≲Λ_{QCD}^{'}, where QCD^{'} is characterized by a single scale Λ_{QCD}^{'} with no light pions. A twin baryon number asymmetry leads to a successful dark matter (DM) candidate: the spin-3/2 twin baryon, Δ^{'}∼b^{'}b^{'}b^{'}, with a dynamically determined mass (∼5Λ_{QCD}^{'}) in the preferred range for the DM-to-baryon ratio Ω_{DM}/Ω_{baryon}≃5. Gauging the U(1)^{'} group leads to twin atoms (Δ^{'}-τ^{'}[over ¯] bound states) that are successful ADM candidates in significant regions of parameter space, sometimes with observable changes to DM halo properties. Direct detection signatures satisfy current bounds, at times modified by dark form factors. PMID:26430985
Twin Higgs Asymmetric Dark Matter
García, Isabel García; March-Russell, John
2015-01-01
We study Asymmetric Dark Matter (ADM) in the context of the minimal (Fraternal) Twin Higgs solution to the little hierarchy problem, with a twin sector with gauged $SU(3)' \\times SU(2)'$, a twin Higgs, and only third generation twin fermions. Naturalness requires the QCD$^\\prime$ scale $\\Lambda'_{\\rm QCD} \\simeq 0.5 - 20 \\ {\\rm GeV}$, and $t'$ to be heavy. We focus on the light $b'$ quark regime, $m_{b'} \\lesssim \\Lambda'_{\\rm QCD}$, where QCD$^\\prime$ is characterised by a single scale $\\Lambda'_{\\rm QCD}$ with no light pions. A twin baryon number asymmetry leads to a successful DM candidate: the spin-3/2 twin baryon, $\\Delta' \\sim b'b'b'$, with a dynamically determined mass ($\\sim 5 \\Lambda'_{\\rm QCD}$) in the preferred range for the DM-to-baryon ratio $\\Omega_{\\rm DM}/\\Omega_{\\rm baryon} \\simeq 5$. Gauging the $U(1)'$ group leads to twin atoms ($\\Delta'$ - $\\bar {\\tau'}$ bound states) that are successful ADM candidates in significant regions of parameter space, sometimes with observable changes to DM halo ...
Asymmetric dark matter in braneworld cosmology
Energy Technology Data Exchange (ETDEWEB)
Meehan, Michael T.; Whittingham, Ian B., E-mail: Michael.Meehan@my.jcu.edu.au, E-mail: Ian.Whittingham@jcu.edu.au [School of Engineering and Physical Sciences, James Cook University, Townsville, 4811 Australia (Australia)
2014-06-01
We investigate the effect of a braneworld expansion era on the relic density of asymmetric dark matter. We find that the enhanced expansion rate in the early universe predicted by the Randall-Sundrum II (RSII) model leads to earlier particle freeze-out and an enhanced relic density. This effect has been observed previously by Okada and Seto (2004) for symmetric dark matter models and here we extend their results to the case of asymmetric dark matter. We also discuss the enhanced asymmetric annihilation rate in the braneworld scenario and its implications for indirect detection experiments.
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; Csand, M; Csrg?, 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; Tomek, M; Torii, H; Towell, R S; Tserruya, I; van Hecke, H W; Vargyas, M; Vazquez-Zambrano, E; Veicht, A; Velkovska, J; Vrtesi, R; Virius, M; Vrba, V; Vznuzdaev, E; Wang, X R; Watanabe, D; Watanabe, K; Watanabe, Y; Watanabe, Y S; Wei, F; Whitaker, S; Wolin, S; Woody, C L; Wysocki, M; Yamaguchi, Y L; Yanovich, A; Yokkaichi, S; Yoon, I; You, Z; Younus, I; Yushmanov, I E; Zajc, W A; Zelenski, A; Zhou, S
2014-01-01
We report on $J/\\psi$ production from asymmetric Cu+Au heavy-ion collisions at $\\sqrt{s_{_{NN}}}$=200 GeV at the Relativistic Heavy Ion Collider at both forward (Cu-going direction) and backward (Au-going direction) rapidities. The nuclear modification of $J/\\psi$ yields in Cu$+$Au collisions in the Au-going direction is found to be comparable to that in Au$+$Au collisions when plotted as a function of the number of participating nucleons. In the Cu-going direction, $J/\\psi$ production shows a stronger suppression. This difference is comparable in magnitude and has the same sign as the difference expected from shadowing effects due to stronger low-$x$ gluon suppression in the larger Au nucleus. The relative suppression is opposite to that expected from hot nuclear matter dissociation, since a higher energy density is expected in the Au-going direction.
DAMA annual modulation effect and asymmetric mirror matter
Addazi, A; Bernabei, R; Belli, P; Cappella, F; Cerulli, R; Incicchitti, A
2015-01-01
The long-standing model-independent annual modulation effect measured by the DAMA Collaboration is examined in the framework of asymmetric mirror dark matter interacting with target nuclei in the detector via the kinetic mixing between mirror and ordinary photons. The allowed physical ranges for the kinetic mixing parameter are obtained taking into account various existing uncertainties in nuclear and particle physics quantities as well as in the density and velocity distributions of dark matter.
Energy Technology Data Exchange (ETDEWEB)
Sebille, F. [SUBATECH, Ecole des Mines de Nantes, Universite de Nantes, CNRS/IN2P3, Nantes (France)], E-mail: sebille@subatech.in2p3.fr; Figerou, S.; Mota, V. de la [SUBATECH, Ecole des Mines de Nantes, Universite de Nantes, CNRS/IN2P3, Nantes (France)
2009-05-01
The exotic structures expected in the outermost layer of neutron stars are investigated in a new approach. It is based on the DYnamical WAvelets in Nuclei (DYWAN) model of nuclear collisions. This microscopic dynamical approach is an Extended Time-Dependent Hartree-Fock description based on a wavelet representation. The model addresses the dynamical exploration of complex nuclear structures, beyond the Wigner-Seitz (WS) approximation and without any assumption on their final shapes. The present study focuses on exotic phases of cold matter evidenced dynamically at sub-saturation densities, currently within a pure mean field framework, before tackling the effects of the multi-particle correlations in a forthcoming study. Starting from inhomogeneous initial conditions provided by nuclei located on an initial crystalline lattice, the exotic structures result from a dynamical self-consistent treatment where, in principle, the nuclear system can freely self-organize, modify the lattice structure or even break the lattice and the initial matter distribution symmetries. In this work nuclei are initially slightly excited with low-lying collective modes. The system can then explore geometrical configurations with similar energies, without being trapped in the vicinity of a local minimum. In this quantum framework, different effects are analyzed, among them the sensitivity to the equation of state and to the proton fraction.
Solar constraints on asymmetric dark matter
Lopes, Ilidio; 10.1088/0004-637X/757/2/130
2012-01-01
The dark matter content of the Universe is likely to be a mixture of matter and antimatter, perhaps comparable to the measured asymmetric mixture of baryons and antibaryons. During the early stages of the Universe, the dark matter particles are produced in a process similar to baryogenesis, and dark matter freeze-out depends on the dark matter asymmetry and the annihilation cross section (s-wave and p-wave annihilation channels). In these \\eta-parametrised asymmetric dark matter models (\\eta-ADM), the dark matter particles have an annihilation cross section close to the weak interaction cross section, and a value of \\eta-dark matter asymmetry close to the baryon asymmetry \\eta_B. Furthermore, we assume that dark matter scattering of baryons, namely, the spin-independent scattering cross section, is of the same order as the range of values suggested by several theoretical particle physics models used to explain the current unexplained events reported in the DAMA/LIBRA, CoGeNT and CRESST experiments. Here, we c...
International Nuclear Information System (INIS)
Realistic versions of the M3Y effective nucleon-nucleon interaction have been used to calculate the basic properties of asymmetric nuclear matter within a non-relativistic Hartree-Fock scheme. Special attention was devoted to the dependence of the binding energy, pressure and incompressibility upon the neutron-proton asymmetry. Our results reproduce reasonably well the empirical value of the symmetry energy and the softening of the equation of state for neutron-rich nuclear matter, as suggested in several supernova studies. The same effective interaction has been further used to calculate the interaction potential between neutron-rich nuclei within an extended version of the double-folding model, where the knock-on exchange and the isospin dependence of the nucleon-nucleon interaction are treated explicitly. The symmetry (isospin-dependent) term of the central nucleus-nucleus potential was found to be negligible compared to the isoscalar term. An exploratory study of the elastic 8He,11Li+14C scattering was performed using the new folded potentials, and possible signatures of the 8He,11Li neutron halos in these processes have been discussed. (orig.)
Baryon Destruction by Asymmetric Dark Matter
Davoudiasl, Hooman; Sigurdson, Kris; Tulin, Sean
2011-01-01
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.
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.
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 1012-1010, would induce a change in solar neutrino fluxes in disagreement with current neutrino flux measurements. This result is also confirmed by helioseismology data. A natural consequence of this model is suppressed annihilation, thereby reducing the tension between indirect and direct dark matter detection experiments, but the model also allows a greatly enhanced annihilation cross section. All the cosmological ?ADM scenarios that we discuss have a relic dark matter density ?h 2 and baryon asymmetry ?B in agreement with the current WMAP measured values, ?DM h 2 = 0.1109 0.0056 and ?B = 0.88 1010.
Solar Constraints on Asymmetric Dark Matter
Lopes, Ilídio; Silk, Joseph
2012-10-01
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 η-parameterized asymmetric dark matter (ηADM) models, the dark matter particles have an annihilation cross section close to the weak interaction cross section, and a value of dark matter asymmetry η close to the baryon asymmetry η 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 ηADM 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 η-asymmetry with a value in the interval 10-12-10-10, would induce a change in solar neutrino fluxes in disagreement with current neutrino flux measurements. This result is also confirmed by helioseismology data. A natural consequence of this model is suppressed annihilation, thereby reducing the tension between indirect and direct dark matter detection experiments, but the model also allows a greatly enhanced annihilation cross section. All the cosmological ηADM scenarios that we discuss have a relic dark matter density Ωh 2 and baryon asymmetry η B in agreement with the current WMAP measured values, ΩDM h 2 = 0.1109 ± 0.0056 and η B = 0.88 × 10-10.
DAMA annual modulation effect and asymmetric mirror matter
Energy Technology Data Exchange (ETDEWEB)
Addazi, A.; Berezhiani, Z. [Universita di L' Aquila, Dipartimento di Scienze Fisiche e Chimiche, Coppito, AQ (Italy); INFN, Laboratori Nazionali del Gran Sasso, Assergi, AQ (Italy); Bernabei, R.; Belli, P. [Universita di Roma ' ' Tor Vergata' ' , Dipartimento di Fisica, Rome (Italy); INFN, Tor Vergata, Rome (Italy); Cappella, F.; Cerulli, R. [INFN, Laboratori Nazionali del Gran Sasso, Assergi, AQ (Italy); Incicchitti, A. [Universita di Roma ' ' La Sapienza' ' , Roma, Dipartimento di Fisica, Rome (Italy); INFN, Roma (Italy)
2015-08-15
The long-standing model-independent annual modulation effect measured by DAMA Collaboration is examined in the context of asymmetric mirror dark matter, assuming that dark atoms interact with target nuclei in the detector via kinetic mixing between mirror and ordinary photons, both being massless. The relevant ranges for the kinetic mixing parameter are obtained taking into account various existing uncertainties in nuclear and particle physics quantities as well as characteristic density and velocity distributions of dark matter in different halo models. (orig.)
Yong, Gao-Chan
2016-01-01
It is generally considered that an atomic nucleus is always compact. Based on the isospin-dependent Boltzmann nuclear transport model, here I show that large block nuclear matter or excited nuclear matter may both be hollow. The size of the inner bubble in these matter is affected by the charge number of nuclear matter. The existence of hollow nuclear matter may have many implications in nuclear or atomic physics or astrophysics as well as some practical applications.
Yong, Gao-Chan
2016-01-01
It is generally considered that an atomic nucleus is always compact. Based on the isospin-dependent Boltzmann nuclear transport model, here I show that large block nuclear matter or excited nuclear matter may both be hollow. And the size of inner bubble in these matter is affected by the charge number of nuclear matter. Existence of hollow nuclear matter may have many implications in nuclear or atomic physics or astrophysics as well as some practical applications.
International Nuclear Information System (INIS)
We reexamine effects of the ρ-ω meson mixing mediated by nucleon polarizations on the symmetry energy in isospin-asymmetric nuclear matter. Taking into account the rearrangement term neglected in previous studies by others, we evaluate the ρ-ω mixing angle in a novel way within the relativistic mean-field models with and without chiral limits. It is found that the symmetry energy is significantly softened at high densities contrary to the finding in earlier studies. As the first step of going beyond the lowest-order calculations, we also solve the Dyson equation for the ρ-ω mixing. In this case, it is found that the symmetry energy is not only significantly softened by the ρ-ωmixing at suprasaturation densities, similar to the lowest-order ρ-ω mixing, but interestingly also softened at subsaturation densities. In addition, the softening of the symmetry energy at subsaturation densities can be partly suppressed by the nonlinear self-interaction of the σ meson.
ADMonium: Asymmetric Dark Matter Bound State
Bi, Xiao-Jun; Kang, Zhaofeng; Ko, P; Li, Jinmian; Li, Tianjun
2016-01-01
We propose a novel framework for asymmetric scalar dark matter (ADM), which has interesting collider phenomenology in terms of an unstable ADM bound state (ADMonium) produced via Higgs portals. ADMonium is a natural consequence of the basic features of ADM: the (complex scalar) ADM is charged under a dark local $U(1)_d$ symmetry which is broken at a low scale and provides a light gauge boson $X$. The dark gauge coupling is strong and then ADM can annihilate away into $X$-pair effectively. The...
Asymmetric Dark Matter and Dark Radiation
Blennow, Mattias; Mena, Olga; Redondo, Javier; Serra, Paolo
2012-01-01
Asymmetric Dark Matter (ADM) models invoke a particle-antiparticle asymmetry, similar to the one observed in the Baryon sector, to account for the Dark Matter (DM) abundance. Both asymmetries are usually generated by the same mechanism and generally related, thus predicting DM masses around 5 GeV in order to obtain the correct density. The main challenge for successful models is to ensure efficient annihilation of the thermally produced symmetric component of such a light DM candidate without violating constraints from collider or direct searches. A common way to overcome this involves a light mediator, into which DM can efficiently annihilate and which subsequently decays into Standard Model particles. Here we explore the scenario where the light mediator decays instead into lighter degrees of freedom in the dark sector that act as radiation in the early Universe. While this assumption makes indirect DM searches challenging, it leads to signals of extra radiation at BBN and CMB. Under certain conditions, pre...
Asymmetric Dark Matter in the Shear--dominated Universe
Iminniyaz, Hoernisa
2016-01-01
We explore the relic abundance of asymmetric Dark Matter in shear--dominated universe in which it is assumed the universe is expanded anisotropically. The modified expansion rate leaves its imprint on the relic density of asymmetric Dark Matter particles if the asymmetric Dark Matter particles are decoupled in shear dominated era. We found the relic abundances for particle and anti--particle are increased. The particle and anti--particle abundances are almost in the same amount for appropriat...
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
Continuous flavor symmetries and the stability of asymmetric dark matter
Bishara, Fady; Zupan, Jure
2015-01-01
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 ...
The phases of isospin asymmetric matter in the two flavor NJL model
Lawley, S.; Bentz, W.; Thomas, A.W.
2005-01-01
We investigate the phase diagram of isospin asymmetric matter at T=0 in the two flavor Nambu-Jona-Lasinio model. Our approach describes the single nucleon as a confined quark-diquark state, the saturation properties of nuclear matter at normal densities, and the phase transition to normal or color superconducting quark matter at higher densities. The resulting equation of state of charge neutral matter is discussed.
The phases of isospin asymmetric matter in the two flavor NJL model
Energy Technology Data Exchange (ETDEWEB)
S. Lawley; W. Bentz; A. W. Thomas
2005-04-01
We investigate the phase diagram of isospin asymmetric matter at T=0 in the two flavor Nambu-Jona-Lasinio model. Our approach describes the single nucleon as a quark-diquark bound state, the saturation properties of nuclear matter at normal densities, and the phase transition to normal or color superconducting quark matter at higher densities. The resulting equation of state of charge neutral matter is discussed.
ADMonium: Asymmetric Dark Matter Bound State
Bi, Xiao-Jun; Ko, P; Li, Jinmian; Li, Tianjun
2016-01-01
We propose a novel framework for asymmetric scalar dark matter (ADM), which has interesting collider phenomenology in terms of an unstable ADM bound state (ADMonium) produced via Higgs portals. ADMonium is a natural consequence of the basic features of ADM: the (complex scalar) ADM is charged under a dark local $U(1)_d$ symmetry which is broken at a low scale and provides a light gauge boson $X$. The dark gauge coupling is strong and then ADM can annihilate away into $X$-pair effectively. Therefore, the ADM can form bound state due to its large self-interaction via $X$ mediation. To explore the collider signature of ADMonium, we propose that ADM has a two-Higgs doublet portal. The ADMonium can have a sizable mixing with the heavier Higgs boson, which admits a large cross section of ADMonium production associated with $b\\bar b$. Of particular interest, our setup nicely explains the recent di-photon anomaly at 750 GeV via the events from ${\\rm ADMonium}\\ra 2X(\\ra e^+e^-)$, where the electrons are identified as ...
Asymmetric Dark Matter in the Shear--dominated Universe
Iminniyaz, Hoernisa
2016-01-01
We explore the relic abundance of asymmetric Dark Matter in shear--dominated universe in which it is assumed the universe is expanded anisotropically. The modified expansion rate leaves its imprint on the relic density of asymmetric Dark Matter particles if the asymmetric Dark Matter particles are decoupled in shear dominated era. We found the relic abundances for particle and anti--particle are increased. The particle and anti--particle abundances are almost in the same amount for appropriate annihilation cross section which makes the indirect detection possible for asymmetric Dark Matter. We use the present day Dark Matter density from the observation to find the constraints on the parameter space in this model.
Asymmetric dark matter and effective number of neutrinos
Kitabayashi, Teruyuki; Kurosawa, Yoshihiro
2016-02-01
We study the effect of the MeV-scale asymmetric dark matter annihilation on the effective number of neutrinos Neff at the epoch of the big bang nucleosynthesis. If the asymmetric dark matter χ couples more strongly to the neutrinos ν than to the photons γ and electrons e-, Γχ γ ,χ e≪Γχ ν , or Γχ γ ,χ e≫Γχ ν, the lower mass limit on the asymmetric dark matter is about 18 MeV for Neff≃3.0 .
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
Abundance of Asymmetric Dark Matter in Brane World Cosmology
Iminniyaz, Hoernisa
2015-01-01
Relic abundance of asymmetric Dark Matter particles in brane world cosmological scenario is investigated in this article. Hubble expansion rate is enhanced in brane world cosmology and it affects the relic abundance of asymmetric Dark Matter particles. We analyze how the relic abundance of asymmetric Dark Matter is changed in this model. We show that in such kind of nonstandard cosmological scenario, indirect detection of asymmetric Dark Matter is possible if the cross section is small enough which let the anti--particle abundance kept in the same amount with the particle. We show the indirect detection signal like Fermi--LAT constraints can be used to such model only when the cross section and the 5 dimensional Planck mass scale are in appropriate values.
Relativistic Effects in Nuclear Matter and Nuclei
van Dalen, E.N.E.(Institute for Theoretical Physics, Tübingen University, Tübingen, D-72076, Germany); Müther, H
2010-01-01
The status of relativistic nuclear many-body calculations of nuclear systems to be built up in terms of protons and neutrons is reviewed. In detail, relativistic effects on several aspects of nuclear matter such as the effective mass, saturation mechanism, and the symmetry energy are considered. This review will especially focus on isospin asymmetric issues, since these aspects are of high interest in astrophysical and nuclear structure studies. Furthermore, from the experimental side these a...
Exotic States of Nuclear Matter
Lombardo, Umberto; Baldo, Marcello; Burgio, Fiorella; Schulze, Hans-Josef
2008-02-01
pt. A. Theory of nuclear matter EOS and symmetry energy. Constraining the nuclear equation of state from astrophysics and heavy ion reactions / C. Fuchs. In-medium hadronic interactions and the nuclear equation of state / F. Sammarruca. EOS and single-particle properties of isospin-asymmetric nuclear matter within the Brueckner theory / W. Zuo, U. Lombardo & H.-J. Schulze. Thermodynamics of correlated nuclear matter / A. Polls ... [et al.]. The validity of the LOCV formalism and neutron star properties / H. R. Moshfegh ... [et al.]. Ferromagnetic instabilities of neutron matter: microscopic versus phenomenological approaches / I. Vidaã. Sigma meson and nuclear matter saturation / A. B. Santra & U. Lombardo. Ramifications of the nuclear symmetry energy for neutron stars, nuclei and heavy-ion collisions / A. W. Steiner, B.-A. Li & M. Prakash. The symmetry energy in nuclei and nuclear matter / A. E. L. Dieperink. Probing the symmetry energy at supra-saturation densities / M. Di Toro et al. Investigation of low-density symmetry energy via nucleon and fragment observables / H. H. Wolter et al. Instability against cluster formation in nuclear and compact-star matter / C. Ducoin ... [et al.]. Microscopic optical potentials of nucleon-nucleus and nucleus-nucleus scattering / Z.-Y. Ma, J. Rong & Y.-Q. Ma -- pt. B. The neutron star crust: structure, formation and dynamics. Neutron star crust beyond the Wigner-Seitz approximation / N. Chamel. The inner crust of a neutron star within the Wigner-Seitz method with pairing: from drip point to the bottom / E. E. Saperstein, M. Baldo & S. V. Tolokonnikov. Nuclear superfluidity and thermal properties of neutron stars / N. Sandulescu. Collective excitations: from exotic nuclei to the crust of neutron stars / E. Khan, M. Grasso & J. Margueron. Monte Carlo simulation of the nuclear medium: fermi gases, nuclei and the role of Pauli potentials / M. A. Pérez-García. Low-density instabilities in relativistic hadronic models / C. Providência et al. Quartetting in nuclear matter and [symbol] particle condensation in nuclear systems / G. Röpke & P. Schuck et al. -- pt. C. Neutron star structure and dynamics. Shear viscosity of neutron matter from realistic nuclear interactions / O. Benhar & M. Valli. Protoneutron star dynamo: theory and observations / A. Bonanno & V. Urpin. Magnetic field dissipation in neutron stars: from magnetars to isolated neutron stars / J. A. Pons. Gravitational radiation and equations of state in super-dense cores of core-collapse supernovae / K. Kotake. Joule heating in the cooling of magnetized neutron stars / D. N. Aguilera, J. A. Pons & J. A. Miralles. Exotic fermi surface of dense neutron matter / M. V. Zverev, V. A. Khodel & J. W. Clark. Coupling of nuclear and electron modes in relativistic stellar matter / A. M. S. Santos et al. Neutron stars in the relativistic Hartree-Fock theory and hadron-quark phase transition / B. Y. Sun ... [et al.] -- pt. D. Prospects of present and future observations. Measurements of neutron star masses / D. G. Yakovlev. Dense nuclear matter: constraints from neutron stars / J. M. Lattimer. Neutron star versus heavy-ion data: is the nuclear equation of state hard or soft? / J. Schaffner-Bielich ... [et al.]. Surface emission from x-ray dim isolated neutron stars / R. Turolla. High energy neutrino astronomy / E. Migneco. What gravitational waves say about the inner structure of neutron stars / V. Ferrari. Reconciling 2 M[symbol] pulsars and SN1987A: two branches of neutron stars / P. Haensel, M. Bejger & J. L. Zdunik. EOS of dense matter and fast rotation of neutron stars / J. L. Zdunik ... [et al.] -- pt. E. Quark and strange matter in neutron stars. Bulk viscosity of color-superconducting quark matter / M. Alford. Chiral symmetry restoration and quark deconfinement at large densities and temperature / A. Drago, L. Bonanno & A. Lavagno. Color superconducting quark matter in compact stars / D. B. Blaschke, T. Klähn & F. Sandin. Thermal hadronization, Hawking-Unruh radiation and event horizon in QCD / P. Castorina. Ferromagnetism in the QCD phase diagram / T. Tatsumi. Asymmetric neutrino emission in quark matter and pulsar kicks / I. Sagert & J. Schaffner-Bielich. Effects of the transition of neutron stars to quark stars on the cooling / T. Noda ... [et al.]. The energy release - stellar angular momentum independence in rotating compact stars undergoing first-order phase transitions / M. Bejger ... [et al.]. Hyperon-quark mixed phase in dense matter / T. Maruyama ... [et al.]. Nucleation of quark matter in neutron stars: role of color superconductivity / I. Bombaci, G. Lugones & I. Vidaña. The bulk viscosity and r-mode instability of strange quark matter / B. A. Sa'd. Neutrino trapping in neutron stars in the presence of Kaon condensation / A. Li ... [et al.]. P. Auger Observatory: status and preliminary results / A. Insolia -- pt. F. Nuclear structure from laboratory to stars. Recent advances in the theory of nuclear forces and its impact on microscopic nuclear structure / R. Machleidt. Kohn-Sham density functional approach to nuclear binding / X. Viñas ... [et al.]. Structure and decay of Kaon-condensed hypernuclei / T. Muto. Isoscalar and isovector nuclear matter properties and giant resonances / H. Sagawa & S. Yoshida. The Skyrme interaction and its tensor component / G. Col, P. F. Bortignon & H. Sagawa. Spin-isospin physics and ICHOR project / H. Sakai for the ICHOR collaboration. Neutron skin thickness of [symbol]Zr determined by (p, n) and (n, p) reactions / K. Yako, H. Sakai & H. Sagawa. Synthesis of super-heavy nuclei in a modified di-nuclear system model / E. G. Zhao et al. -- pt. G. Nuclear superfluidity. Mesoscopic treatment of superfluid neutron current in solid star crust / B. Carter. Equation of state in the inner crust of neutron stars: discussion of the unbound neutrons states / J. Margueron, N. Van Giai & N. Sandulescu. Pairing and bound states in nuclear matter / J. W. Clark & A. Sedrakian. Pairing in BCS theory and beyond / L. G. Cao, U. Lombardo & P. Schuck. Pinning and binding energies for vortices in neutron stars: comments on recent results / P. M. Pizzochero. Structure of a vortex in the inner crust of neutron stars / P. Avogadro ... [et al.]. The dynamics of vortex pinning in the neutron star crust / B. Link -- pt. H. Poster session. Microscopic data and supernovae evolution / P. Blottiau, Ph. Mellor & J. Margueron. Parity doublet model applied to neutron star / V. Dexheimer, S. Schramm & H. Stoecker. Structure of hybrid stars / D. Jaccarino, U. Lombardo & G. X. Peng. Nuclear three-body force from the Nijmegen potential / Z. H. Li ... [et al.]. Monopole excitations in QRPA on top of HFB / J. Li, G. Colò & J. Meng. The influence of the [symbol]-field on neutron stars / A. J. Mi, W. Zuo & A. Li. Magnetization of color-flavor locked matter / J. Noronha & I. A. Shovkovy. Ab initio pairing gap calculation for a slab of nuclear matter with Paris and Argonne V18 bare NN-potentials / S. S. Pankratov et al. Hybrid neutron stars within the Nambu-Jona-Lasinio model and confinement / S. Plumari et al. A study of pairing interaction in a separable form / Y. Tian, Z. Ma & P. Ring. Isospin dependence of nuclear matter / E. N. E Van Dalen ... [et al.]. Ejected elements from the envelope of compact stars by QCD phase transition / N. Yasutake et al. Microscopic three-body force effect on nucleon-nucleon cross sections / H. F. Zhang et al. Tensor correlations and single-particle states in medium-mass nuclei / W. Zou et al.
Fixed-Velocity Chiral Sum Rules for Nuclear Matter
Cohen, Thomas D.; Broniowski, Wojciech
1997-01-01
Infinite sets of sum rules involving the excitations of infinite nuclear matter are derived using only completeness, the current algebra implicit in QCD, and relativistic covariance. The sum rules can be used for isospin-asymmetric nuclear matter, including neutron matter. They relate the chiral condensate and the isospin density to weighted sums over states with fixed velocity relative to the nuclear matter ground state.
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)
Upper Bounds on Asymmetric Dark Matter Self Annihilation Cross Sections
Ellwanger, Ulrich
2012-01-01
Most models for asymmetric dark matter allow for dark matter self annihilation processes, which can wash out the asymmetry at temperatures near and below the dark matter mass. We study the coupled set of Boltzmann equations for the symmetric and antisymmetric dark matter number densities, and derive conditions applicable to a large class of models for the absence of a significant wash-out of an asymmetry. These constraints are applied to various existing scenarios. In the case of left- or right-handed sneutrinos, very large electroweak gaugino masses, or very small mixing angles are required.
Directory of Open Access Journals (Sweden)
Lenske H.
2016-01-01
Full Text Available Recent developments of nuclear structure theory for exotic nuclei are addressed. The inclusion of hyperons and nucleon resonances is discussed. Nuclear multipole response functions, hyperon interactions in infinite matter and in neutron stars and theoretical aspects of excitations of nucleon resonances in nuclei are discussed.
Continuous flavor symmetries and the stability of asymmetric dark matter
Bishara, Fady; Zupan, Jure
2015-01-01
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.
Continuous Flavor Symmetries and the Stability of Asymmetric Dark Matter
Bishara, Fady
2014-01-01
Generically, the asymmetric interactions in asymmetric dark matter (ADM) models 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.
Asymmetric Dark Matter Models and the LHC Diphoton Excess
DEFF Research Database (Denmark)
Frandsen, Mads T.; Shoemaker, Ian M.
2016-01-01
The existence of dark matter (DM) and the origin of the baryon asymmetry are persistent indications that the SM is incomplete. More recently, the ATLAS and CMS experiments have observed an excess of diphoton events with invariant mass of about 750 GeV. One interpretation of this excess is decays of...... may have for models of asymmetric DM that attempt to account for the similarity of the dark and visible matter abundances....
Asymmetric dark matter and the Sun
DEFF Research Database (Denmark)
Frandsen, Mads Toudal; Sarkar, Subir
2010-01-01
Cold dark matter particles with an intrinsic matter-antimatter asymmetry do not annihilate after gravitational capture by the Sun and can affect its interior structure. The rate of capture is exponentially enhanced when such particles have self-interactions of the right order to explain structure...... formation on galactic scales. A `dark baryon' of mass 5 GeV is a natural candidate and has the required relic abundance if its asymmetry is similar to that of ordinary baryons. We show that such particles can solve the `solar composition problem'. The predicted small decrease in the low energy neutrino...
Survey of Reflection-Asymmetric Nuclear Deformations
Olsen, Erik; Birge, Noah; Erler, Jochen; Nazarewicz, Witek; Perhac, Alex; Schunck, Nicolas; Stoitsov, Mario; Nuclei Collaboration
2015-10-01
Due to spontaneous symmetry breaking it is possible for a nucleus to have a deformed shape in its ground state. It is theorized that atoms whose nuclei have reflection-asymmetric or pear-like deformations could have non-zero electric dipole moments (EDMs). Such a trait would be evidence of CP-violation, a feature that goes beyond the Standard Model of Physics. It is the purpose of this project to predict which nuclei exhibit a reflection-asymmetric deformation and which of those would be the best candidates for an EDM measuring experiment. Using nuclear Density Functional Theory along with the new computer code AxialHFB and massively parallel computing we calculated ground state nuclear properties for thousands of even-even nuclei across the nuclear chart: from light to superheavy and from stable to short-lived systems. Six different Energy Density Functionals (EDFs) were used to assess systematic errors in our calculations. Overall, 140 even-even nuclei (near and among the lantanides and actinides and in the superheavy region near N = 184) were predicted by all 6 EDFs to have a pear-like deformation. The case of 112Xe also proved curious as it was predicted by 5 EDFs to have a pear-like deformation despite its proximity to the two-proton drip line. Deceased.
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 γ-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
Gamma ray constraints on flavor violating asymmetric dark matter
DEFF Research Database (Denmark)
Masina, I.; Panci, P.; Sannino, F.
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 Te......V. We find that the Fermi constraints rule out the flavor violating asymmetric Dark Matter interpretation of the charged cosmic ray anomalies....
International Nuclear Information System (INIS)
Recent advances in variational and perturbative theories are surveyed which offer genuine promise that nuclear matter will soon become a viable tool for investigating nuclear interactions. The basic elements of the hypernetted chain expansion for Jastrow variational functions are briefly reviewed, and comparisons of variational and perturbative results for a series of increasingly complicated systems are presented. Prospects for investigating realistic forces are assessed and the unresolved, open problems are summarized
Chromomagnetism in nuclear matter
Ranjan, Akhilesh; Raina, P. K.
2011-01-01
Quarks are color charged particles. Due to their motion there is a strong possibility of generation of color magnetic field. It is shown that however hadrons are color singlet particles they may have non-zero color magnetic moment. Due to this color magnetic moment hadrons can show color interaction. In this paper we have studied the chromomagnetic properties of nuclear matter.
Decaying Asymmetric Dark Matter Relaxes the AMS-Fermi Tension
Feng, Lei
2013-01-01
The first result of AMS-02 confirms the positron fraction excess observed by PAMELA, but in the dark matter (DM) interpretation, its softer spectrum 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, and find that at the two-body decay level a bosonic ADM around 2.4 TeV and decaying to\\mu^-\\tau^+ can significantly improve the fits. Based on the R-parity-violating supersymmetry with operators LLE^c, we propose a minimal model to realize that ADM scenario: Introducing a pair of singlets (X,\\bar X) and coupling them to the visible sector via LH_uX, we then obtain a leptonic decaying ADM with TeV-scale mass.
Asymmetric Dark Matter Models and the LHC Diphoton Excess
Frandsen, Mads T
2016-01-01
The existence of dark matter (DM) and the origin of the baryon asymmetry are persistent indications that the SM is incomplete. More recently, the ATLAS and CMS experiments have observed an excess of diphoton events with invariant mass of about 750 GeV. One interpretation of this excess is decays of a new spin-0 particle with a sizable diphoton partial width, e.g. induced by new heavy weakly charged particles. These are also key ingredients in models cogenerating asymmetric DM and baryons via sphaleron interactions and an initial particle asymmetry. We explore what consequences the new scalar may have for models of asymmetric DM that attempt to account for the similarity of the dark and visible matter abundances.
Asymmetric capture of Dirac dark matter by the Sun
Energy Technology Data Exchange (ETDEWEB)
Blennow, Mattias; Clementz, Stefan [Department of Theoretical Physics, School of Engineering Sciences, KTH Royal Institute of Technology, Albanova University Center,106 91, Stockholm (Sweden)
2015-08-18
Current problems with the solar model may be alleviated if a significant amount of dark matter from the galactic halo is captured in the Sun. We discuss the capture process in the case where the dark matter is a Dirac fermion and the background halo consists of equal amounts of dark matter and anti-dark matter. By considering the case where dark matter and anti-dark matter have different cross sections on solar nuclei as well as the case where the capture process is considered to be a Poisson process, we find that a significant asymmetry between the captured dark particles and anti-particles is possible even for an annihilation cross section in the range expected for thermal relic dark matter. Since the captured number of particles are competitive with asymmetric dark matter models in a large range of parameter space, one may expect solar physics to be altered by the capture of Dirac dark matter. It is thus possible that solutions to the solar composition problem may be searched for in these type of models.
Asymmetric capture of Dirac dark matter by the Sun
International Nuclear Information System (INIS)
Current problems with the solar model may be alleviated if a significant amount of dark matter from the galactic halo is captured in the Sun. We discuss the capture process in the case where the dark matter is a Dirac fermion and the background halo consists of equal amounts of dark matter and anti-dark matter. By considering the case where dark matter and anti-dark matter have different cross sections on solar nuclei as well as the case where the capture process is considered to be a Poisson process, we find that a significant asymmetry between the captured dark particles and anti-particles is possible even for an annihilation cross section in the range expected for thermal relic dark matter. Since the captured number of particles are competitive with asymmetric dark matter models in a large range of parameter space, one may expect solar physics to be altered by the capture of Dirac dark matter. It is thus possible that solutions to the solar composition problem may be searched for in these type of models
Asymmetric capture of Dirac dark matter by the Sun
Blennow, Mattias; Clementz, Stefan
2015-08-01
Current problems with the solar model may be alleviated if a significant amount of dark matter from the galactic halo is captured in the Sun. We discuss the capture process in the case where the dark matter is a Dirac fermion and the background halo consists of equal amounts of dark matter and anti-dark matter. By considering the case where dark matter and anti-dark matter have different cross sections on solar nuclei as well as the case where the capture process is considered to be a Poisson process, we find that a significant asymmetry between the captured dark particles and anti-particles is possible even for an annihilation cross section in the range expected for thermal relic dark matter. Since the captured number of particles are competitive with asymmetric dark matter models in a large range of parameter space, one may expect solar physics to be altered by the capture of Dirac dark matter. It is thus possible that solutions to the solar composition problem may be searched for in these type of models.
Constraining Asymmetric Dark Matter through observations of compact stars
DEFF Research Database (Denmark)
Kouvaris, Christoforos; Tinyakov, Peter
2011-01-01
We put constraints on asymmetric dark matter candidates with spin-dependent interactions based on the simple existence of white dwarfs and neutron stars in globular clusters. For a wide range of the parameters (WIMP mass and WIMP-nucleon cross section), WIMPs can be trapped in progenitors in large...... numbers and once the original star collapses to a white dwarf or a neutron star, these WIMPs might self-gravitate and eventually collapse forming a mini-black hole that eventually destroys the star. We impose constraints competitive to direct dark matter search experiments, for WIMPs with masses down to...
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.)
Asymmetric vector mesons produced in nuclear collisions
Dremin, I M
2016-01-01
It is argued that the experimentally observed phenomenon of asymmetric shapes of vector mesons produced in nuclear media during high energy nucleus-nucleus collisions can be explained as Fano-Feshbach resonances. It has been observed that the mass distributions of lepton pairs created at meson decays decline from the traditional Breit-Wigner shape with some excess in the low-mass wing of the resonance. It is clear that the whole phenomenon is related to some interaction with the nuclear medium. Moreover, it can be further detalized in quantum mechanics as the interference of direct and continuum states in Fano-Feshbach effect. To reveal the nature of the interaction it is proposed to use a phenomenological model of the additional contribution due to Cherenkov gluons. They can be created because of the excess of the refractivity index over 1 just in the low-mass wing as required by the classical Cherenkov treatment. In quantum mechanics, this requirement is related to the positive real part of the interaction ...
A Model of Asymmetric Hadronic Dark Matter and Leptogenesis
Yang, Wei-Min
2015-01-01
The paper suggests a model to account for the common origins of the asymmetric dark matter (ADM) and matter-antimatter asymmetry. The ADM nature is a stable hadronic particle consisting of a heavy color scalar and a light $u$ quark, which is formed after the QCD phase transition. At the early stage the ADM are in thermal equilibrium through collisions with the nucleons, moreover, they can emit the $\\gamma$ photons with $0.32$ MeV energy. However they are decoupling and become the dark matter at the temperature about $130$ MeV. The mass upper limit of the ADM is predicted as $M_{D}<1207$ GeV. It is feasible and promising to test the model in future experiments.
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
International Nuclear Information System (INIS)
As the incident energy increases the time scales of the heavy ion collisions decrease. The interaction time, i.e. the time elapsing between the contact-separation moments is around 10-22 and 10-21 s at intermediate energies of the order of 20 ≤ Ebomb ≤ 100 MeV/nucleon. At the same time, with the increasing energy the reaction mechanisms evolve and nucleon-nucleon collisions develop entailing a pre-equilibrium strong emission. Dynamical phenomena occur, as for instance, the particle and nuclear fragment emission from a nuclear matter neck linking the nuclear partners. The de-excitation of the strongly compressed and heated nuclei proceeds rapidly. Consequently, the experimental situation becomes more and more complex as the bombarding energy increases due to the superposition of the times scales of different processes. In order to achieve an as precise as possible description of the intermediate energy reaction mechanisms the events have to be detected with high efficiency (4 π angular coverage and low detection thresholds). The off-equilibrium nuclear matter created in heavy ion collisions was investigated in a series of experiments based on multidetectors like NAUTILUS and INDRA. Performances concerning the angular coverage granularity and thresholds are mentioned. Also mentioned are important results obtained so far concerning the existence of a radial collective flow in the de-excitation of hot nuclei, the emission of fragments from a neck intermediate zone, as well as, the effects of proximity (space time correlations)
Exposing asymmetric gray matter vulnerability in amyotrophic lateral sclerosis
Directory of Open Access Journals (Sweden)
Matthew S. Devine
2015-01-01
Full Text Available Limb weakness in amyotrophic lateral sclerosis (ALS is typically asymmetric. Previous studies have identified an effect of limb dominance on onset and spread of weakness, however relative atrophy of dominant and non-dominant brain regions has not been investigated. Our objective was to use voxel-based morphometry (VBM to explore gray matter (GM asymmetry in ALS, in the context of limb dominance. 30 ALS subjects were matched with 17 healthy controls. All subjects were right-handed. Each underwent a structural MRI sequence, from which GM segmentations were generated. Patterns of GM atrophy were assessed in ALS subjects with first weakness in a right-sided limb (n = 15 or left-sided limb (n = 15. Within each group, a voxelwise comparison was also performed between native and mirror GM images, to identify regions of hemispheric GM asymmetry. Subjects with ALS showed disproportionate atrophy of the dominant (left motor cortex hand area, irrespective of the side of first limb weakness (p < 0.01. Asymmetric atrophy of the left somatosensory cortex and temporal gyri was only observed in ALS subjects with right-sided onset of limb weakness. Our VBM protocol, contrasting native and mirror images, was able to more sensitively detect asymmetric GM pathology in a small cohort, compared with standard methods. These findings indicate particular vulnerability of dominant upper limb representation in ALS, supporting previous clinical studies, and with implications for cortical organisation and selective vulnerability.
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)
Discovering asymmetric dark matter with anti-neutrinos
International Nuclear Information System (INIS)
We discuss possible signatures of Asymmetric Dark Matter (ADM) through dark matter decays to neutrinos. We specifically focus on scenarios in which the Standard Model (SM) baryon asymmetry is transferred to the dark sector (DS) through higher dimensional operators in chemical equilibrium. In such cases, the dark matter (DM) carries lepton and/or baryon number, and we point out that for a wide range of quantum number assignments, by far the strongest constraints on dark matter decays come from decays to neutrinos through the ''neutrino portal'' operator HL. Together with the facts that ADM favors lighter DM masses ? a few GeV and that the decays would lead only to anti-neutrinos and no neutrinos (or vice versa), the detection of such decays at neutrino telescopes would provide compelling evidence for ADM. We discuss current and future bounds on models where the DM decays to neutrinos through operators of dimension ? 6. For dimension 6 operators, the scale suppressing the decay is bounded to be ?>10121013 GeV
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.)
Nuclear matter and electron scattering
Energy Technology Data Exchange (ETDEWEB)
Sick, I. [Dept. fuer Physik und Astronomie, Univ. Basel (Switzerland)
1998-06-01
We show that inclusive electron scattering at large momentum transfer allows a measurement of short-range properties of nuclear matter. This provides a very valuable constraint in selecting the calculations appropriate for predicting nuclear matter properties at the densities of astrophysical interest. (orig.)
Bound states in nuclear matter
International Nuclear Information System (INIS)
Full text: The formation of bound states in dilute nuclear matter will be discussed and its implications for the equation of state and composition of astrophysical plasma in supernova envelopes. Bulk properties of dense nuclear and hypernuclear matter will be discussed in the framework of the Brueckner theory. (author)
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.)
Covariant density functional theory for nuclear matter
Energy Technology Data Exchange (ETDEWEB)
Badarch, U.
2007-07-01
The present thesis is organized as follows. In Chapter 2 we study the Nucleon-Nucleon (NN) interaction in Dirac-Brueckner (DB) approach. We start by considering the NN interaction in free-space in terms of the Bethe-Salpeter (BS) equation to the meson exchange potential model. Then we present the DB approach for nuclear matter by extending the BS equation for the in-medium NN interaction. From the solution of the three-dimensional in-medium BS equation, we derive the DB self-energies and total binding energy which are the main results of the DB approach, which we later incorporate in the field theoretical calculation of the nuclear equation of state. In Chapter 3, we introduce the basic concepts of density functional theory in the context of Quantum Hadrodynamics (QHD-I). We reach the main point of this work in Chapter 4 where we introduce the DDRH approach. In the DDRH theory, the medium dependence of the meson-nucleon vertices is expressed as functionals of the baryon field operators. Because of the complexities of the operator-valued functionals we decide to use the mean-field approximation. In Chapter 5, we contrast microscopic and phenomenological approaches to extracting density dependent meson-baryon vertices. Chapter 6 gives the results of our studies of the EOS of infinite nuclear matter in detail. Using formulas derived in Chapters 4 and 5 we calculate the properties of symmetric and asymmetric nuclear matter and pure neutron matter. (orig.)
Propagation of neutrinos in nuclear matter
International Nuclear Information System (INIS)
We study the elementary interactions between neutrinos and dense matter in a proto-neutron star. Equations of state obtained with different nuclear effective interactions (Skyrme, Gogny, Relativistic Lagrangians) are first discussed. Then, we characterize their stability in spin and isospin. We derive magnetic susceptibilities for all isospin asymmetry values as a function of Landau parameters Gππ'0 (where π, π' = 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)
Condensed Matter Nuclear Science
Takahashi, Akito; Ota, Ken-Ichiro; Iwamura, Yashuhiro
Preface -- 1. General. Progress in condensed matter nuclear science / A. Takahashi. Summary of ICCF-12 / X. Z. Li. Overview of light water/hydrogen-based low-energy nuclear reactions / G. H. Miley and P. J. Shrestha -- 2. Excess heat and He detection. Development of "DS-reactor" as the practical reactor of "cold fusion" based on the "DS-cell" with "DS-cathode" / Y. Arata and Y.-C. Zhang. Progress in excess of power experiments with electrochemical loading of deuterium in palladium / V. Violante ... [et al.]. Anomalous energy generation during conventional electrolysis / T. Mizuno and Y. Toriyabe. "Excess heat" induced by deuterium flux in palladium film / B. Liu ... [et al.]. Abnormal excess heat observed during Mizuno-type experiments / J.-F. Fauvarque, P. P. Clauzon and G. J.-M. Lallevé. Seebeck envelope calorimetry with a Pd|D[symbol]O + H[symbol]SO[symbol] electrolytic cell / W.-S. Zhang, J. Dash and Q. Wang. Observation and investigation of nuclear fusion and self-induced electric discharges in liquids / A. I. Koldamasov ... [et al.]. Description of a sensitive seebeck calorimeter used for cold fusion studies / E. Storms. Some recent results at ENEA / M. Apicella ... [et al.]. Heat measurement during plasma electrolysis / K. Iizumi ... [et al.]. Effect of an additive on thermal output during electrolysis of heavy water with a palladium cathode / Q. Wang and J. Dash. Thermal analysis of calorimetric systems / L. D'Aulerio ... [et al.]. Surface plasmons and low-energy nuclear reactions triggering / E. Castagna ... [et al.]. Production method for violent TCB jet plasma from cavity / F. Amini. New results and an ongoing excess heat controversy / L. Kowalski ... [et al.] -- 3. Transmutation. Observation of surface distribution of products by X-ray fluorescence spectrometry during D[symbol] gas permeation through Pd Complexes / Y. Iwamura ... [et al.]. Discharge experiment using Pd/CaO/Pd multi-layered cathode / S. Narita ... [et al.]. Producing transmutation element on multi-layered Pd sample by deuterium permeation / H. Yamada ... [et al.]. Experimental observation and combined investigation of high-performance fusion of iron-region isotopes in optimal growing microbiological associations / V. I. Vysotskii ... [et al.]. Research into low-energy nuclear reactions in cathode sample solid with production of excess heat, stable and radioactive impurity nuclides / A. B. Karabut. Influence of parameters of the glow discharge on change of structure and the isotope composition of the cathode materials / I. B. Savvatimova and D. V. Gavritenkov. Elemental analysis of palladium electrodes after Pd/Pd light water critical electrolysis / Y. Toriyabe ... [et al.]. Progress on the study of isotopic composition in metallic thin films undergone to electrochemical loading of hydrogen / M. Apicella ... [et al.]. In situ accelerator analyses of palladium complex under deuterium permeation / A. Kitamura ... [et al.]. High-resolution mass spectrum for deuterium (hydrogen) gas permeating palladium film / Q. M. Wei ... [et al.]. ICP-MS analysis of electrodes and electrolytes after HNO[symbol]/H[symbol]O electrolysis / S. Taniguchi ... [et al.]. The Italy-Japan project - fundamental research on cold transmutation process for treatment of nuclear wastes / A. Takahashi, F. Celani and Y. Iwamura -- 4. Nuclear physics approach. Reproducible nuclear emissions from Pd/PdO:Dx heterostructure during controlled exothermic deuterium desorption / A. G. Lipson ... [et al.]. Correct identification of energetic alpha and proton tracks in experiments on CR-39 charged particle detection during hydrogen desorption from Pd/PdO:H[symbol] heterostructure / A. S. Roussetski ... [et al.]. Intense non-linear soft X-ray emission from a hydride target during pulsed D bombardment / G. H. Miley ... [et al.]. Enhancement of first wall damage in ITER type TOKAMAK due to LENR effects / A. G. Lipson, G. H. Miley and H. Momota. Generation of DD-reactions in a ferroelectric KD[symbol]PO[symbol] single crystal during transition through curie point (Tc = 220K) / A. G. Lipson ... [et al.]. Study of energetic and temporal characteristics of X-ray emission from solid-state cathode medium of high-current glow discharge / A. B. Karabut. A novel LiF-based detector for X-ray imaging in hydrogen loaded Ni films under laser irradiation / R. M. Montereali ... [et al.]. Observation and modeling of the ordered motion of hypothetical magnetically charged particles on the multilayer surface and the problem of low-energy fusion / S. V. Adamenko and V. I. Vysotskii -- 5. Material science. Evidence of superstoichiometric H/D lenr active sites and high-temperature superconductivity in a hydrogen-cycled Pd/PdO / A. G. Lipson ... [et al.]. New procedures to make active, fractal-like surfaces on thin Pd wires / F. Celani ... [et al.]. Using resistivity to measure H/Pd and D/Pd loading: Method and significance / M. C. H. McKubre and F. L. Tanzella. Measurements of the temperature coefficient of electric resistivity of hydrogen overloaded Pd / A. Spallone ... [et al.]. Magnetic interaction of hypothetical particles moving beneath the electrode/electrolyte interface to elucidate evolution mechanism of vortex appeared on Pd surface after long-term evolution of deuterium in 0.1 m LiOD / H. Numata and M. Ban. Unusual structures on the material surfaces irradiated by low-energy ions / B. Rodionov and I. Savvatimova -- 6. Theory. Context for understanding why particular nanoscale crystals turn-on faster and other LENR effects / S. R. Chubb. Models for anomalies in condensed matter deuterides / P. L. Hagelstein. Time-dependent EQPET analysis of TSC / A. Takahashi. Unifying theory of low-energy nuclear reaction and transmutation processes in deuterated/hydrogenated metals, acoustic cavitation, glow discharge, and deuteron beam experiments / Y. E. Kim and A. L. Zubarev. Catalytic fusion and the interface between insulators and transition metals / T. A. Chubb. Multiple scattering of deuterium wave function near surface of palladium lattice / X. Z. Li ... [et al.]. Theoretical comparison between semi-classical and quantum tunneling effect / F. Frisone. New cooperative mechanisms of low-energy nuclear reactions using super low-energy external field / F. A. Gareev and I. E. Zhidkova. Polyneutron theory of transmutation / J. C. Fisher. The thermal conduction from the centers of the nuclear reactions in solids / K.-I. Tsuchiya. Four-body RST general nuclear wavefunctions and matrix elements / I. Chaudhary and P. L. Hagelstein. Study on formation of tetrahedral or octahedral symmetric condensation by hopping of alkali or alkaline-earth metal ion / H. Miura. Calculations of nuclear reactions probability in a crystal lattice of lanthanum deuteride / V. A. Kirkinskii and Yu. A. Novikov. Possible coupled electron and electron neutrino in nucleus and its physical catalysis effect on D-D cold fusion into helium in Pd / M. Fukuhara. Tunnel resonance of electron wave and force of fluctuation / M. Ban. Types of nuclear fusion in solids / N. Yabuuchi. Neutrino-dineutron reactions (low-energy nuclear reactions induced by D[symbol] gas permeation through Pd complexes - Y. Iwamura effect) / V. Muromtsev, V. Platonov and I. Savvatimova. An explanation of earthquakes by the blacklight process and hydrogen fusion / H. Yamamoto. Theoretical modeling of electron flow action on probability of nuclear fusion of deuterons / A. I. Goncharov and V. A. Kirkinskii.
Condensed Matter Nuclear Science
Biberian, Jean-Paul
2006-02-01
1. General. A tribute to gene Mallove - the "Genie" reactor / K. Wallace and R. Stringham. An update of LENR for ICCF-11 (short course, 10/31/04) / E. Storms. New physical effects in metal deuterides / P. L. Hagelstein ... [et al.]. Reproducibility, controllability, and optimization of LENR experiments / D. J. Nagel -- 2. Experiments. Electrochemistry. Evidence of electromagnetic radiation from Ni-H systems / S. Focardi ... [et al.]. Superwave reality / I. Dardik. Excess heat in electrolysis experiments at energetics technologies / I. Dardik ... [et al.]. "Excess heat" during electrolysis in platinum/K[symbol]CO[symbol]/nickel light water system / J. Tian ... [et al.]. Innovative procedure for the, in situ, measurement of the resistive thermal coefficient of H(D)/Pd during electrolysis; cross-comparison of new elements detected in the Th-Hg-Pd-D(H) electrolytic cells / F. Celani ... [et al.]. Emergence of a high-temperature superconductivity in hydrogen cycled Pd compounds as an evidence for superstoihiometric H/D sites / A. Lipson ... [et al.]. Plasma electrolysis. Calorimetry of energy-efficient glow discharge - apparatus design and calibration / T. B. Benson and T. O. Passell. Generation of heat and products during plasma electrolysis / T. Mizuno ... [et al.]. Glow discharge. Excess heat production in Pd/D during periodic pulse discharge current in various conditions / A. B. Karabut. Beam experiments. Accelerator experiments and theoretical models for the electron screening effect in metallic environments / A. Huke, K. Czerski, and P. Heide. Evidence for a target-material dependence of the neutron-proton branching ratio in d+d reactions for deuteron energies below 20keV / A. Huke ... [et al.]. Experiments on condensed matter nuclear events in Kobe University / T. Minari ... [et al.]. Electron screening constraints for the cold fusion / K. Czerski, P. Heide, and A. Huke. Cavitation. Low mass 1.6 MHz sonofusion reactor / R. Stringham. Particle detection. Research into characteristics of X-ray emission laser beams from solidstate cathode medium of high-current glow discharge / A. B. Karabut. Charged particles from Ti and Pd foils / L. Kowalski ... [et al.]. Cr-39 track detectors in cold fusion experiments: review and perspectives / A. S. Roussetski. Energetic particle shower in the vapor from electrolysis / R. A. Oriani and J. C. Fisher. Nuclear reactions produced in an operating electrolysis cell / R. A. Oriani and J. C. Fisher. Evidence of microscopic ball lightning in cold fusion experiments / E. H. Lewis. Neutron emission from D[symbol] gas in magnetic fields under low temperature / T. Mizuno ... [et al.]. Energetic charged particle emission from hydrogen-loaded Pd and Ti cathodes and its enhancement by He-4 implantation / A. G. Lipson ... [et al.]. H-D permeation. Observation of nuclear transmutation reactions induced by D[symbol] gas permeation through Pd complexes / Y. Iwamura ... [et al.]. Deuterium (hydrogen) flux permeating through palladium and condensed matter nuclear science / Q. M. Wei ... [et al.]. Triggering. Precursors and the fusion reactions in polarized Pd/D-D[symbol]O system: effect of an external electric field / S. Szpak, P. A. Mosier-Boss, and F. E. Gordon. Calorimetric and neutron diagnostics of liquids during laser irradiation / Yu. N. Bazhutov ... [et al.]. Anomalous neutron capture and plastic deformation of Cu and Pd cathodes during electrolysis in a weak thermalized neutron field: evidence of nuclei-lattice exchange / A. G. Lipson and G. H. Miley. H-D loading. An overview of experimental studies on H/Pd over-loading with thin Pd wires and different electrolytic solutions / A. Spallone ... [et al.] -- 3. Transmutations. Photon and particle emission, heat production, and surface transformation in Ni-H system / E. Campari ... [et al.]. Surface analysis of hydrogen-loaded nickel alloys / E. Campari ... [et al.]. Low-energy nuclear reactions and the leptonic monopole / G. Lochak and L. Urutskoev. Results of analysis of Ti foil after glow discharge with deuterium / I. B. Savvatimova and D. V. Gavr
Chiral thermodynamics of nuclear matter
Energy Technology Data Exchange (ETDEWEB)
Fiorilla, Salvatore
2012-10-23
The equation of state of nuclear matter is calculated at finite temperature in the framework of in-medium chiral perturbation theory up to three-loop order. The dependence of its thermodynamic properties on the isospin-asymmetry is investigated. The chiral quark condensate is evaluated for symmetric nuclear matter. Its behaviour as a function of density and temperature sets important nuclear physics constraints for the QCD phase diagram.
Chiral thermodynamics of nuclear matter
International Nuclear Information System (INIS)
The equation of state of nuclear matter is calculated at finite temperature in the framework of in-medium chiral perturbation theory up to three-loop order. The dependence of its thermodynamic properties on the isospin-asymmetry is investigated. The chiral quark condensate is evaluated for symmetric nuclear matter. Its behaviour as a function of density and temperature sets important nuclear physics constraints for the QCD phase diagram.
Limits on momentum-dependent asymmetric dark matter with CRESST-II
Angloher, G; Bucci, C; Canonica, L; Defay, X; Erb, A; Feilitzsch, F v; Iachellini, N Ferreiro; Gorla, P; Gütlein, A; Hauff, D; Jochum, J; Kiefer, M; Kluck, H; Kraus, H; Lanfranchi, J -C; Loebell, J; Münster, A; Pagliarone, C; Petricca, F; Potzel, W; Pröbst, F; Reindl, F; Schäffner, K; Schieck, J; Schönert, S; Seidel, W; Stodolsky, L; Strandhagen, C; Strauss, R; Tanzke, A; Thi, H H Trinh; Türkoğlu, C; Uffinger, M; Ulrich, A; Usherov, I; Wawoczny, S; Willers, M; Wüstrich, M; Zöller, A
2016-01-01
The usual assumption in direct dark matter searches is to only consider the spin-dependent or spin-independent scattering of dark matter particles. However, especially in models with light dark matter particles $\\mathcal{O}(\\mathrm{GeV/c^2})$, operators which carry additional powers of the momentum transfer $q^2$ can become dominant. One such model based on asymmetric dark matter has been invoked to overcome discrepancies in helioseismology and an indication was found for a particle with preferred mass of 3 $\\mathrm{GeV/c^2}$ and cross section of $10^{-37} \\mathrm{cm^2}$. Recent data from the CRESST-II experiment, which uses cryogenic detectors based on $\\mathrm{CaWO_4}$ to search for nuclear recoils induced by dark matter particles, are used to constrain these momentum-dependent models. The low energy threshold of 307 eV for nuclear recoils of the detector used, allows us to rule out the proposed best fit value above.
Nuclear physics and dense matter
International Nuclear Information System (INIS)
Crucial to understanding the properties of dense matter in supernova explosions and neutron stars is determining the role of the nuclei present in such matter. Because many of the properties of the matter do not depend strongly on the fine details of nuclear structure, the liquid drop model of the nucleus provides a convenient starting point. The influence of the matter outside the nuclei on the properties of the nuclei must, however, be taken into account. One studies several aspects of the liquid drop model and its applications. In particular one first studies the theory of surface tension as used in the liquid drop model. Then a refined version of the compressible liquid drop model was developed which enables a redetermination semi-empirically of the properties of bulk nuclear matter. Finally, resultant nuclear mass formula is applied to the equation of state of hot, dense matter
Flavor and collider signatures of asymmetric dark matter
Kim, Ian-Woo; Zurek, Kathryn M.
2014-02-01
We consider flavor constraints on, and collider signatures of, asymmetric dark matter (ADM) via higher dimension operators. In the supersymmetric models we consider, R-parity-violating (RPV) operators carrying B -L interact with n dark matter particles X through an interaction of the form W =XnOB -L, where OB-L=q?dc, ucdcdc, ??ec. This interaction ensures that the lightest ordinary supersymmetric particle is unstable to decay into the X sector, leading to a higher multiplicity of final state particles and reduced missing energy at a collider. Flavor-violating processes place constraints on the scale of the higher dimension operator, impacting whether the LOSP decays promptly. While the strongest limitations on RPV from n -n oscillations and proton decay do not apply to ADM, we analyze the constraints from meson mixing, ?-e conversion, ??3e and b?s?+?-. We show that these flavor constraints, even in the absence of flavor symmetries, allow parameter space for prompt decay to the X sector, with additional jets and leptons in exotic flavor combinations. We study the constraints from existing 8 TeV LHC Supersymmetry (SUSY) searches with (i) 2-6 jets plus missing energy and (ii) 1-2 leptons, 3-6 jets plus missing energy, comparing the constraints on ADM-extended supersymmetry with the usual supersymmetric simplified models.
Flavor and Collider Signatures of Asymmetric Dark Matter
Kim, Ian-Woo
2014-01-01
We consider flavor constraints on, and collider signatures of, Asymmetric Dark Matter (ADM) via higher dimension operators. In the supersymmetric models we consider, R-parity violating (RPV) operators carrying B-L interact with n dark matter (DM) particles X through an interaction of the form W = X^n O_{B-L}, where O_{B-L} = q l d^c, u^c d^c d^c, l l e^c. This interaction ensures that the lightest ordinary supersymmetric particle (LOSP) is unstable to decay into the X sector, leading to a higher multiplicity of final state particles and reduced missing energy at a collider. Flavor-violating processes place constraints on the scale of the higher dimension operator, impacting whether the LOSP decays promptly. While the strongest limitations on RPV from n-\\bar{n} oscillations and proton decay do not apply to ADM, we analyze the constraints from meson mixing, mu-e conversion, mu -> 3 e and b -> s l^+ l^-. We show that these flavor constraints, even in the absence of flavor symmetries, allow parameter space for pr...
Takeshita, Hisako; Sawa, Hitoshi
2005-01-01
?-Catenin can promote adhesion at the cell cortex and mediate Wnt signaling in the nucleus. We show that, in Caenorhabditis elegans, both WRM-1/?-catenin and LIT-1 kinase localize to the anterior cell cortex during asymmetric cell division but to the nucleus of the posterior daughter afterward. Both the cortical and nuclear localizations are regulated by Wnts and are apparently coupled. We also found that the daughters show different nuclear export rates for LIT-1. Our results indicate that W...
What can we learn from nuclear matter instabilities
International Nuclear Information System (INIS)
We discuss the features of instabilities in binary systems, in particular for asymmetric nuclear matter. We show the relevance for the interpretation of results obtained in experiments and in 'ab initio' simulations of the reaction 124 Sn + nat Sn at 50 MeV/n (authors)
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
Shear viscosity of nuclear matter
Xu, Jun
2013-01-01
In this talk I report my recent study on the shear viscosity of neutron-rich nuclear matter from a relaxation time approach. An isospin- and momentum-dependent interaction is used in the study. Effects of density, temperature, and isospin asymmetry of nuclear matter on its shear viscosity have been discussed. Similar to the symmetry energy, the symmetry shear viscosity is defined and its density and temperature dependence are studied.
The phase diagram of bulk nuclear matter
International Nuclear Information System (INIS)
Recent analyses of nuclear multifragmentation and compound nuclear data determined the pressure-density-temperature phase diagram of bulk nuclear matter. A condensation model, modified to account for nuclear energies, was used to describe the fragment yields and finite size scaling techniques were used to determine the bulk property of nuclear matter from finite, charged samples of nuclear matter, i.e. nuclei. (orig.)
Anatomy of nuclear matter fundamentals
Patra, S K; Singh, S K; Bhuyan, M
2014-01-01
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
Bosonic variables in nuclear matters
International Nuclear Information System (INIS)
It is shown that the boson theoretical interpretation of nuclear forces nessecitates the introduction of bosonic variables within the state function of nuclear matter. In this framework the 2-boson exchange plays a decisive role and calls for the introduction of special selfenergy diagrams. This generalized scheme is discussed with the help of a solvable field theoretical model. (orig.)
Linear response of homogeneous nuclear matter with energy density functionals
Pastore, A.; Davesne, D.; Navarro, J.
2015-03-01
Response functions of infinite nuclear matter with arbitrary isospin asymmetry are studied in the framework of the random phase approximation. The residual interaction is derived from a general nuclear Skyrme energy density functional. Besides the usual central, spin-orbit and tensor terms it could also include other components as new density-dependent terms or three-body terms. Algebraic expressions for the response functions are obtained from the Bethe-Salpeter equation for the particle-hole propagator. Applications to symmetric nuclear matter, pure neutron matter and asymmetric nuclear matter are presented and discussed. Spin-isospin strength functions are analyzed for varying conditions of density, momentum transfer, isospin asymmetry, and temperature for some representative Skyrme functionals. Particular attention is paid to the discussion of instabilities, either real or unphysical, which could manifest in finite nuclei.
Linear response of homogeneous nuclear matter with energy density functionals
International Nuclear Information System (INIS)
Response functions of infinite nuclear matter with arbitrary isospin asymmetry are studied in the framework of the random phase approximation. The residual interaction is derived from a general nuclear Skyrme energy density functional. Besides the usual central, spin–orbit and tensor terms it could also include other components as new density-dependent terms or three-body terms. Algebraic expressions for the response functions are obtained from the Bethe–Salpeter equation for the particle–hole propagator. Applications to symmetric nuclear matter, pure neutron matter and asymmetric nuclear matter are presented and discussed. Spin–isospin strength functions are analyzed for varying conditions of density, momentum transfer, isospin asymmetry, and temperature for some representative Skyrme functionals. Particular attention is paid to the discussion of instabilities, either real or unphysical, which could manifest in finite nuclei
Linear response of homogeneous nuclear matter with energy density functionals
Pastore, A; Navarro, J
2014-01-01
Response functions of infinite nuclear matter with arbitrary isospin asymmetry are studied in the framework of the random phase approximation. The residual interaction is derived from a general nuclear Skyrme energy density functional. Besides the usual central, spin-orbit and tensor terms it could also include other components as new density-dependent terms or three-body terms. Algebraic expressions for the response functions are obtained from the Bethe-Salpeter equation for the particle-hole propagator. Applications to symmetric nuclear matter, pure neutron matter and asymmetric nuclear matter are presented and discussed. Spin-isospin strength functions are analyzed for varying conditions of density, momentum transfer, isospin asymmetry, and temperature for some representative Skyrme functionals. Particular attention is paid to the discussion of instabilities, either real or unphysical, which could manifest in finite nuclei.
More on nucleon-nucleon cross sections in symmetric and asymmetric matter
Sammarruca, F.; Krastev, P.
2005-01-01
Following a recent work, we present numerical results for total two-nucleon effective cross sections in isospin symmetric and asymmetric matter. The present calculations include the additional effect of Pauli blocking of the final states.
Energy Technology Data Exchange (ETDEWEB)
Chapman, S.
1992-11-01
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.
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
International Nuclear Information System (INIS)
We study a nonlinear nuclear equation of state in the framework of a relativistic mean field theory. We investigate the possible thermodynamic instability in a warm and dense asymmetric nuclear medium where a phase transition from nucleonic matter to resonance dominated Δ matter can take place. Such a phase transition is characterized by both mechanical instability (fluctuations on the baryon density) and by chemical-diffusive instability (fluctuations on the isospin concentration) in asymmetric nuclear matter. Similarly to the liquid-gas phase transition, the nucleonic and the Δ-matter phase have a different isospin density in the mixed phase. In the liquid-gas phase transition, the process of producing a larger neutron excess in the gas phase is referred to as isospin fractionation. A similar effects can occur in the nucleon-Δ matter phase transition due essentially to a negative Δ-particles excess in asymmetric nuclear matter. In this context, we investigate also the effects of power law effects, due to the possible presence of nonextensive statistical mechanics effects
Limits on momentum-dependent asymmetric dark matter with CRESST-II
Angloher, G.(Max-Planck-Institut fr Physik, 80805, Munich, Germany); Bento, A.; Bucci, C.; Canonica, L.; Defay, X.; Erb, A.(Physik-Department, Technische Universitt Mnchen, 85747, Garching, Germany); Feilitzsch, F. v.; Iachellini, N. Ferreiro(Max-Planck-Institut fr Physik, 80805, Munich, Germany); Gorla, P.; Gtlein, A.; Hauff, D.; Jochum, J.; Kiefer, M; Kluck, H.(Institut fr Hochenergiephysik der sterreichischen Akademie der Wissenschaften, 1050, Wien, Austria); Kraus, H.
2016-01-01
The usual assumption in direct dark matter searches is to only consider the spin-dependent or spin-independent scattering of dark matter particles. However, especially in models with light dark matter particles $\\mathcal{O}(\\mathrm{GeV/c^2})$, operators which carry additional powers of the momentum transfer $q^2$ can become dominant. One such model based on asymmetric dark matter has been invoked to overcome discrepancies in helioseismology and an indication was found for a particle with pref...
International Nuclear Information System (INIS)
We present a phenomenological theory of nuclei that incorporates clustering at the nuclear surface in a general form. The theory explains the recently extracted large symmetry energy by Natowitz et al., at low densities of nuclear matter and is fully consistent with the static properties of nuclei. In a phenomenological way, clusters of all sizes and shapes along with medium modifications are included. Symmetric nuclear matter properties are discussed in detail. Arguments are given that lead to an equation of state of nuclear matter consistent with clustering in the low-density region. We also discuss properties of asymmetric nuclear matter. Because of clustering, an interesting interpretation of the equation of state of asymmetric nuclear matter emerges. As a framework, an extended version of Thomas-Fermi theory is adopted for nuclei which also contain phenomenological pairing and Wigner contributions. This theory connects the nuclear matter equation of state, which incorporates clustering at low densities, with clustering in nuclei at the nuclear surface. Calculations are performed for various equations of state of nuclear matter. We consider measured binding energies of 2149 nuclei for N, Z? 8. The importance of the quartic term in symmetry energy is demonstrated at and below the saturation density of nuclear matter. It is shown that it is largely related to the use of, ab initio, a realistic equation of state of neutron matter, particularly the contribution arising from the three neutron interactions and somewhat to clustering. Reasons for these are discussed. Because of clustering the neutron skin thickness in nuclei is found to reduce significantly. The developed theory predicts situations and regimes to be explored both theoretically and experimentally.
Energy Technology Data Exchange (ETDEWEB)
Heiselberg, H. [NORDITA, Copenhagen (Denmark)
1998-06-01
The kaon energy in a nuclear medium and its dependence on kaon-nucleon and nucleon-nucleon correlations is discussed. The transition from the Lenz potential at low densities to the Hartree potential at high densities can be calculated analytically by making a Wigner-Seitz cell approximation and employing a square well potential. As the Hartree potential is less attractive than the Lenz one, kaon condensation inside cores of neutron stars appears to be less likely than previously estimated. (orig.)
Electron scattering from nuclear matter
International Nuclear Information System (INIS)
We use inclusive electron scattering to study the short-range aspects of nuclear matter wave functions. Comparison to data at large momentum transfer allows detailed studies of P(k, E) at large momenta, N-N correlations and colour transparency. (orig.)
Nuclear matter: new states of dense matter
International Nuclear Information System (INIS)
Heavy ion collisions when involving incident ion velocity of about a quarter of light speed are powerful tools for understanding the behaviour of nuclear matter. Hot nuclei produced in such collisions decay either by evaporation (emission of particles) or by multifragmentation (production of smaller nuclei) or by vaporization (production of particles and light nuclei). These decay processes show strong analogies with liquid-gas transition. 2 new experimental facts support this interpretation: energy fluctuations and abnormal correlations. In the first case fluctuations show the existence of negative heat capacity and in the second case correlations show the possibility of a spinodal decomposition that was, till now only speculated for liquid-gas transitions. (A.C.)
Kaon polarization in nuclear matter
International Nuclear Information System (INIS)
The kaon-nucleon interaction in nuclear matter is considered by taking into account tree graphs, p-wave interaction, pionic intermediate states, kaon fluctuations and some residual interaction. The latter one is constrained by Adler's consistency condition. The K-, K+, K0, anti K0 polarization operators are calculated in cold nuclear matter with arbitrary isotopic composition. An extra s-wave repulsion is found, which probably shifts the critical point of a K- condensation with vanishing kaon momentum to large nucleon densities. Oppositely, an extra p-wave attraction is obtained, which may lead to a K- condensation at vanishing temperatures and densities ρ≥ρc-∼(4-6)ρ0. The spectrum of the kaonic excitations in nuclear matter is analyzed and a new low-lying branch in the K- (and also anti K0) spectrum is found. Its presence may lead to interesting observable consequences, such as the enhancement of the K- yields in heavy-ion reactions. At ρ≥ρc- the frequency of this low-lying branch becomes negative at non-vanishing momentum; that signals the onset of inhomogeneous K-condensation. The K- condensate energy is calculated in the approximation of a small KK coupling constant. Accordingly, neutron matter may undergo a first-order phase transition to proton matter with K- condensate at ρ>ρc-. The temperature dependence of the most important terms of the K- polarization operator is discussed. In a rather wide temperature region 0π/2 a growing temperature enlarges the K-N attraction and promotes the kaon condensation. The possibility of anti K0 condensation is also considered. The question is qualitatively discussed whether proton matter with K- condensate or neutron matter with anti K0 condensate is energetically more favorable. (orig.)
Nuclear and neutron matters at low density
International Nuclear Information System (INIS)
In this study, symmetric and asymmetric nuclear matter, as well as pure neutron matter in the low-density regime, where the density ranges 0.01 fm-3 ? 0.13 fm-3, have been investigated. Two different realistic and accurate two-body forces are considered. These include Argonne V18 and the CD-Bonn, which give quite different equations of state. The binding energy per nucleon as a function of the density is calculated using the Brueckner-Hartree-Fock approximation. Both the conventional (gap) and continuous choice of single-particle energies are utilized. For the sake of comparison, the equation of state within the self-consistent Green's function approach is calculated using the CD-Bonn potential. The contribution of the hole-hole terms leads to a repulsive contribution to the energy per nucleon which increases with the nuclear density. Significantly, very good agreement between the experimental symmetry energy values and those calculated in the self-consistent Green's function and BHF approaches especially at low density, has been accomplished. Finally, The results are compared with those from various many-body approaches, such as variational and relativistic mean field approaches. (orig.)
Nuclear and neutron matters at low density
Energy Technology Data Exchange (ETDEWEB)
Gad, Kh. [Sohag University, Physics Department, Faculty of Science, Sohag (Egypt)
2015-08-15
In this study, symmetric and asymmetric nuclear matter, as well as pure neutron matter in the low-density regime, where the density ranges 0.01 fm{sup -3} ? 0.13 fm{sup -3}, have been investigated. Two different realistic and accurate two-body forces are considered. These include Argonne V18 and the CD-Bonn, which give quite different equations of state. The binding energy per nucleon as a function of the density is calculated using the Brueckner-Hartree-Fock approximation. Both the conventional (gap) and continuous choice of single-particle energies are utilized. For the sake of comparison, the equation of state within the self-consistent Green's function approach is calculated using the CD-Bonn potential. The contribution of the hole-hole terms leads to a repulsive contribution to the energy per nucleon which increases with the nuclear density. Significantly, very good agreement between the experimental symmetry energy values and those calculated in the self-consistent Green's function and BHF approaches especially at low density, has been accomplished. Finally, The results are compared with those from various many-body approaches, such as variational and relativistic mean field approaches. (orig.)
Asymmetric capture of Dirac dark matter by the Sun
Blennow, Mattias
2015-01-01
Current problems with the solar model may be alleviated if a significant amount of dark matter from the galactic halo is captured in the Sun. We discuss the capture process in the case where the dark matter is a Dirac fermion and the background halo consists of equal amounts of dark matter and anti-dark matter. By considering the case where dark matter and anti-dark matter have different cross sections on solar nuclei as well as the case where the capture process is considered to be a Poisson process, we find that a significant asymmetry between the captured dark particles and anti-particles is possible. Such an asymmetry puts a lower bound on the total amount of captured dark matter and could be a possible solution to the solar composition problem.
Temperature Dependent Nuclear Matter Approach
International Nuclear Information System (INIS)
Full text: The nuclear matter approach provides an effective interaction in the presence of a sea of nucleons. Especially it accounts for the Pauli principle which forbids scattering processes into the occupied states of the nucleonic see. It is well suited to describe the bulk properties of nuclei as well as optical potentials beyond 40 MeV incident energy. Difficulties in the description of nucleon-nucleus reactions beyond 70 MeV may indicate the importance of excited doorway states for reaction processes and therefore the optical potentials. In this contribution we consider the g-matrix approach for excited nuclear matter. The g-matrix is evaluated via the Bethe-Goldstone equation with an exact Pauli operator accounting for excitations with arbitrary occupation distributions. The features of the g-matrix with regard to changes in excitation are discussed. (author)
Fermion self-energy in magnetized chirally asymmetric QED matter
Rybalka, D O
2016-01-01
The fermion self-energy is calculated for a cold QED plasma with chiral chemical potential in a magnetic field. It is found that a momentum shift parameter dynamically generated in such a plasma leads to a modification of the chiral magnetic effect current. It is argued that the momentum shift parameter can be relevant for the evolution of magnetic field in the chirally asymmetric primordial plasma in the early Universe.
Asymmetric sneutrino dark matter and the ?b/?DM puzzle
International Nuclear Information System (INIS)
The inferred values of the cosmological baryon and dark matter densities are strikingly similar, but in most theories of the early universe there is no true explanation of this fact; in particular, the baryon asymmetry and thus density depends upon unknown, and a priori unknown and possibly small, CP-violating phases which are independent of all parameters determining the dark matter density. We consider models of dark matter possessing a particle-antiparticle asymmetry where this asymmetry determines both the baryon asymmetry and strongly effects the dark matter density, thus naturally linking ?b and ?dm. We show that sneutrinos can play the role of such dark matter in a previously studied variant of the MSSM in which the light neutrino masses result from higher-dimensional supersymmetry-breaking terms
Nuclear Matter Equations of State and the Neutron Stars
International Nuclear Information System (INIS)
The equations of state (EoS) of relativistic asymmetric nuclear matter are obtainable from assumed form of the interaction Lagrangian. They are one of important inputs to describe the neutron stars. The structure of the neutron stars, i.e. the density of matter and the pressure as functions of radial distance starting from their values at the center of a star, is straightforwardly dependent on EoS. Similarly, a limitation on the total mass of the neutron star can be obtained therefrom. Thus, EoS and the underlying nucleon interactions can be tested also by the means of astronomical observations
Role of isospin in nuclear-matter liquid-gas phase transition
International Nuclear Information System (INIS)
Nuclear matter presents a phase transition of the liquid-gas type. This well-known feature is due to the nuclear interaction profile (mean-range attractive, short-range repulsive). Symmetric-nuclear-matter thermodynamics is thus analogous to that of a Van der Waals fluid. The study shows up to be more complex in the case of asymmetric matter, composed of neutrons and protons in an arbitrary proportion. Isospin, which distinguishes both constituents, gives a measure of this proportion. Studying asymmetric matter, isospin is an additional degree of freedom, which means one more dimension to consider in the space of observables. The nuclear liquid-gas transition is associated with the multi-fragmentation phenomenon observed in heavy-ion collisions, and to compact-star physics: the involved systems are neutron rich, so they are affected by the isospin degree of freedom. The present work is a theoretical study of isospin effects which appear in the asymmetric nuclear matter liquid-gas phase transition. A mean-field approach is used, with a Skyrme nuclear effective interaction. We demonstrate the presence of a first-order phase transition for asymmetric matter, and study the isospin distillation phenomenon associated with this transition. The case of phase separation at thermodynamic equilibrium is compared to spinodal decomposition. Finite size effects are addressed, as well as the influence of the electron gas which is present in the astrophysical context. (author)
Takeshita, Hisako; Sawa, Hitoshi
2005-08-01
beta-Catenin can promote adhesion at the cell cortex and mediate Wnt signaling in the nucleus. We show that, in Caenorhabditis elegans, both WRM-1/beta-catenin and LIT-1 kinase localize to the anterior cell cortex during asymmetric cell division but to the nucleus of the posterior daughter afterward. Both the cortical and nuclear localizations are regulated by Wnts and are apparently coupled. We also found that the daughters show different nuclear export rates for LIT-1. Our results indicate that Wnt signals release cortical WRM-1 from the posterior cortex to generate cortical asymmetry that may control WRM-1 asymmetric nuclear localization by regulating cell polarity. PMID:16077003
Baryogenesis and asymmetric dark matter from the left–right mirror symmetric model
Energy Technology Data Exchange (ETDEWEB)
Yang, Wei-Min, E-mail: wmyang@ustc.edu.cn
2014-08-15
The paper suggests a left–right mirror symmetric model to account for the baryogenesis and asymmetric dark matter. The model can simultaneously accommodate the standard model, neutrino physics, matter–antimatter asymmetry and dark matter. In particular, it naturally and elegantly explains the origin of the baryon and dark matter asymmetries, and clearly gives the close interrelations of them. In addition, the model predicts a number of interesting results, e.g. that the cold dark matter neutrino mass is 3.1 times the proton mass. It is also feasible and promising to test the model in future experiments.
Baryogenesis and asymmetric dark matter from the left–right mirror symmetric model
International Nuclear Information System (INIS)
The paper suggests a left–right mirror symmetric model to account for the baryogenesis and asymmetric dark matter. The model can simultaneously accommodate the standard model, neutrino physics, matter–antimatter asymmetry and dark matter. In particular, it naturally and elegantly explains the origin of the baryon and dark matter asymmetries, and clearly gives the close interrelations of them. In addition, the model predicts a number of interesting results, e.g. that the cold dark matter neutrino mass is 3.1 times the proton mass. It is also feasible and promising to test the model in future experiments
Nuclear charge and neutron radii and nuclear matter: trend analysis
Reinhard, P. -G.; Nazarewicz, W.
2016-01-01
Radii of charge and neutron distributions are fundamental nuclear properties. They depend on both nuclear interaction parameters related to the equation of state of infinite nuclear matter and on quantal shell effects, which are strongly impacted by the presence of nuclear surface. In this work, by studying the dependence of charge and neutron radii, and neutron skin, on nuclear matter parameters, we assess different mechanisms that drive nuclear sizes. We apply nuclear density functional the...
Odundo, Magdalene
2009-01-01
Asymmetrical brings together a series of ceramic works exploring the effects of burnishing, glazes and firing processes on the final manifestation of the form and its surface qualities. The elements of this series of hand built forms came into life almost simultaneously over a period of several weeks. Each dried form was laboriously burnished, covered with slip and burnished again. When dry, the pots were fired in a gas kiln, first in an oxidizing atmosphere, which turned them a natural re...
Quasiparticle interaction in nuclear matter
International Nuclear Information System (INIS)
A microscopic calculation of the quasiparticle interaction in nuclear matter is detailed. In order to take especial care of the contributions from the low momentum states, a model space is introduced. Excluded from the model space, the high momentum states are absorbed into the model interaction. Brueckner theory suggests the choice of a truncated G-matrix as a good approximation for this model interaction. A simple perturbative approach is attempted within the model space. The calculated quasiparticle interaction is consistent with experimental results. (11 tables, 14 figures)
Phase transition from nuclear matter to color superconducting quark matter
Bentz, W.; Horikawa, T.; Ishii, N.; Thomas, A.W.
2002-01-01
We construct the nuclear and quark matter equations of state at zero temperature in an effective quark theory (the Nambu-Jona-Lasinio model), and discuss the phase transition between them. The nuclear matter equation of state is based on the quark-diquark description of the single nucleon, while the quark matter equation of state includes the effects of scalar diquark condensation (color superconductivity). The effect of diquark condensation on the phase transition is discussed in detail.
BCS-BEC crossovers and unconventional phases in dilute nuclear matter. II
Stein, Martin; Huang, Xu-Guang; Clark, John W
2014-01-01
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...
Light clusters in nuclear matter
International Nuclear Information System (INIS)
Within a quantum statistical approach, a in-medium Schroedinger equation is derived for a few-nucleon system embedded in nuclear matter. Medium modifications of the cluster quasiparticles are described by self-energy and Pauli blocking effects. Benchmarks such as the nuclear statistical equilibrium, virial expansion and the relativistic mean field approximation are considered. An interesting effect is the formation of a four- or two-nucleon quantum condensate, showing the crossover from Cooper pairing to Bose-Einstein condensation. The resulting thermodynamic properties are of interest for heavy-ion collisions and astrophysical applications. Quantum condensates and the Mott effect are also of relevance for the structure of finite nuclei, specially dilute excited states like the Hoyle state of 12C. (author)
Light asymmetric dark matter from new strong dynamics
DEFF Research Database (Denmark)
Frandsen, Mads Toudal; Sarkar, Subir; Schmidt-Hoberg, Kai
2011-01-01
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...
Nuclear interactions and hadronic matter
International Nuclear Information System (INIS)
The new generation of heavy ion accelerators and complex experimental devices, developed in the last two decades, give access to new information concerning the dynamics of nuclear collisions and allow to obtain and study in the laboratory the nuclear matter under extreme conditions of density and temperature. Of special interest is the intermediate energy region where the reactions are dominated by the competition between the mean field and nucleon-nucleon interaction. Fundamental aspects of nuclear reaction studies are probed at different instants of a nuclear collision. One can learn about the transport properties of nuclear matter in pure nucleonic regime and understand the modification of the nucleon-nucleon cross section due to various in-medium effects: density effects, effective mass, quantum effects, three-body interactions. With increasing energy, fast particle emission associated with direct nucleon-nucleon collisions in the first steps of the reaction come into play too. At higher energy, flow measurements are crucial tests of the influence of medium effects by probing the elastic part of the nucleon-nucleon collisions. On the other side, at higher incident energies, the characteristics of the nuclear equation of state (EoS) can be studied if local thermal and chemical equilibrium turns out to be established. Understanding of the properties of the nuclear matter in extreme conditions is a fundamental goal. The EoS is also an essential ingredient in the description of the massive stars leading to supernova explosion and neutron star formation. Experimental studies of such aspects needs experimental devices of high complexity which can detect and identify event by event all products coming out from heavy ion interactions at intermediate, relativistic and ultra-relativistic energies, having as complete as possible information on their mass, charge, velocity vector. CHIMERA and FOPI are such devices for intermediate and relativistic energy, respectively. Our group had contributions in their design, construction, operation, calibration and data analysis, part of these activities being the subject of our project financed by CERES National Program. CHIMERA being a new detector, for its calibration in energy, charge and mass of the identified particles, quite large efforts were dedicated for developing consistent calibration procedures. Based on these, correct Data Summary Tapes (DST) are currently produced and analysis activities will start in the near future. Concerning the FOPI detector, our group concentrated in extracting detailed information on the collective phenomena in central and mid-central symmetric heavy ion collisions in the energy range of 90 AMeV - 400 AMeV. We shown that such observables are sensitive to the EoS and the comparison with model calculations evidenced that at such energies a soft EoS could explain the observed experimental trends. Another subject followed up by our group is related to the dependence of the squeeze-out phenomena on the N/Z content of the spectator matter. Such studies could be decisive for extracting the in-medium isospin dependence of the nucleon-nucleon cross section. (authors)
Conditions for Nuclear-Matter Lasers
Yukalov, V. I.
1999-01-01
Conditions are analysed when in dense and hot nuclear matter large amounts of Bose particles can be created. An intensive production of Bose particles is the main necessary condition for realizing their coherent emission similar to radiation from photon lasers. The consideration is based on the multichannel model of nuclear matter. Analysis shows that possible candidates for nuclear--matter lasing are mesons (mainly pions), dibaryons, and gluons.
Asymmetric dark matter may alter the evolution of very low-mass stars and brown dwarfs
International Nuclear Information System (INIS)
We study energy transport by asymmetric dark matter (ADM) in very low-mass stars and brown dwarfs. Our motivation is to explore astrophysical signatures of ADM, which may not otherwise be amenable to indirect dark matter searches. In viable models, the additional cooling of low-mass stellar cores can alter stellar properties. ADM with mass 4 x/GeV pSD∼10-37 cm2 (σpSI∼10-40 cm2) increases the minimum mass of main sequence hydrogen burning, partly determining whether or not the object is a star at all. Similar ADM candidates reduce the luminosities of low-mass stars and accelerate the cooling of brown dwarfs. Such light dark matter is of interest given results from the DAMA and CoGeNT dark matter searches. We discuss possibilities for observing dark matter effects in stars and exploiting these effects to constrain dark matter candidates.
Nuclear charge and neutron radii and nuclear matter: trend analysis
Reinhard, P -G
2016-01-01
Radii of charge and neutron distributions are fundamental nuclear properties. They depend on both nuclear interaction parameters related to the equation of state of infinite nuclear matter and on quantal shell effects, which are strongly impacted by the presence of nuclear surface. In this work, by studying the dependence of charge and neutron radii, and neutron skin, on nuclear matter parameters, we assess different mechanisms that drive nuclear sizes. We apply nuclear density functional theory using a family of Skyrme functionals obtained by means of different optimization protocols targeting specific nuclear properties. By performing the Monte-Carlo sampling of reasonable functionals around the optimal parametrization, we study correlations between nuclear matter paramaters and observables characterizing charge and neutron distributions. We demonstrate the existence of the strong converse relation between the nuclear charge radii and the saturation density of symmetric nuclear matter and also between the n...
Asymmetric dark matter and CP violating scatterings in a UV complete model
Baldes, Iason; Bell, Nicole F.; Millar, Alexander J.; Volkas, Raymond R.
2015-10-01
We explore possible asymmetric dark matter models using CP violating scatterings to generate an asymmetry. In particular, we introduce a new model, based on DM fields coupling to the SM Higgs and lepton doublets, a neutrino portal, and explore its UV completions. We study the CP violation and asymmetry formation of this model, to demonstrate that it is capable of producing the correct abundance of dark matter and the observed matter-antimatter asymmetry. Crucial to achieving this is the introduction of interactions which violate CP with a T2 dependence.
Asymmetric dark matter and CP violating scatterings in a UV complete model
Energy Technology Data Exchange (ETDEWEB)
Baldes, Iason; Bell, Nicole F.; Millar, Alexander J.; Volkas, Raymond R. [ARC Centre of Excellence for Particle Physics at the Terascale,School of Physics, The University of Melbourne, Victoria, 3010 (Australia)
2015-10-21
We explore possible asymmetric dark matter models using CP violating scatterings to generate an asymmetry. In particular, we introduce a new model, based on DM fields coupling to the SM Higgs and lepton doublets, a neutrino portal, and explore its UV completions. We study the CP violation and asymmetry formation of this model, to demonstrate that it is capable of producing the correct abundance of dark matter and the observed matter-antimatter asymmetry. Crucial to achieving this is the introduction of interactions which violate CP with a T{sup 2} dependence.
Asymmetric dark matter and CP violating scatterings in a UV complete model
International Nuclear Information System (INIS)
We explore possible asymmetric dark matter models using CP violating scatterings to generate an asymmetry. In particular, we introduce a new model, based on DM fields coupling to the SM Higgs and lepton doublets, a neutrino portal, and explore its UV completions. We study the CP violation and asymmetry formation of this model, to demonstrate that it is capable of producing the correct abundance of dark matter and the observed matter-antimatter asymmetry. Crucial to achieving this is the introduction of interactions which violate CP with a T2 dependence
Asymmetric Dark Matter and CP Violating Scatterings in a UV Complete Model
Baldes, Iason; Millar, Alexander J; Volkas, Raymond R
2015-01-01
We explore possible asymmetric dark matter models using CP violating scatterings to generate an asymmetry. In particular, we introduce a new model, based on DM fields coupling to the SM Higgs and lepton doublets, $\\overline{L}H$, and explore its UV completions. We study the CP violation and asymmetry formation of this model, to demonstrate that it is capable of producing the correct abundance of dark matter and the observed matter-antimatter asymmetry. Crucial to achieving this is the introduction of interactions which violate CP with a $T^{2}$ dependence.
Does asymmetric dark matter always lead to an anti-neutrino signal?
Fukuda, Hajime; Mukhopadhyay, Satyanarayan
2014-01-01
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.
Lepton-Flavored Asymmetric Dark Matter and Interference in Direct Detection
Hamze, Ali; Koeller, Jason; Trendafilova, Cynthia; Yu, Jiang-Hao
2014-01-01
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...
Asymmetrical sabotage tactics, nuclear facilities/materials, and vulnerability analysis
International Nuclear Information System (INIS)
Full text: The emerging paradigm of a global community wherein post-modern political violence is a fact of life that must be dealt with by safety and security planners is discussed. This paradigm shift in the philosophy of terrorism is documented by analysis of the emerging pattern of asymmetrical tactics being employed by terrorists. Such philosophical developments in violent political movements suggest a shift in the risks that security and safety personnel must account for in their planning for physical protection of fixed site nuclear source facilities like power generation stations and the eventual storage and transportation of the by-products of these facilities like spent nuclear fuel and other high level wastes. This paper presents a framework for identifying these new political realities and related threat profiles, suggests ways in which security planners and administrators can design physical protection practices to meet these emerging threats, and argues for global adoption of standards for the protection of nuclear facilities that could be used as a source site from which terrorists could inflict a mass contamination event and for standards related to the protection of the waste materials that can be used in the production of radiological weapons of mass victimization. (author)
Structure of the subsaturated nuclear matter
Energy Technology Data Exchange (ETDEWEB)
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
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)
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
Cosmic ray-dark matter scattering: a new signature of (asymmetric) dark matter in the gamma ray sky
International Nuclear Information System (INIS)
We consider the process of scattering of Galactic cosmic-ray electrons and protons off of dark matter with the radiation of a final-state photon. This process provides a novel way to search for Galactic dark matter with gamma rays. We argue that for a generic weakly interacting massive particle, barring effects such as co-annihilation or a velocity-dependent cross section, the gamma-ray emission from cosmic-ray scattering off of dark matter is typically smaller than that from dark matter pair-annihilation. However, if dark matter particles cannot pair-annihilate, as is the case for example in asymmetric dark matter scenarios, cosmic-ray scattering with final state photon emission provides a unique window to detect a signal from dark matter with gamma rays. We estimate the expected flux level and its spectral features for a generic supersymmetric setup, and we also discuss dipolar and luminous dark matter. We show that in some cases the gamma-ray emission might be large enough to be detectable with the Fermi Large Area Telescope
Light Asymmetric Dark Matter on the Lattice: SU(2) Technicolor with Two Fundamental Flavors
Lewis, Randy; Sannino, Francesco
2012-01-01
The SU(2) gauge theory with two massless Dirac flavors constitutes the building block of several models of Technicolor. Furthermore it has also been used as a template for the construction of a natural light asymmetric, or mixed type, dark matter candidate. We use explicit lattice simulations to confirm the pattern of chiral symmetry breaking by determining the Goldstone spectrum and therefore show that the dark matter candidate can, de facto, be constituted by a complex Goldstone boson. We also determine the phenomenologically relevant spin one and spin zero isovector spectrum and demonstrate that it is well separated from the Goldstone spectrum.
Mizumoto, Kota; Sawa, Hitoshi
2007-02-01
In C. elegans, Wnt signaling regulates a number of asymmetric cell divisions. During telophase, WRM-1/beta-catenin localizes asymmetrically to the anterior cortex and the posterior daughter's nucleus. However, cortical WRM-1's functions are not known. Here, we use a membrane-targeted form of WRM-1 to show that cortical WRM-1 inhibits Wnt signaling and the nuclear localization of WRM-1. These functions are mediated by APR-1/APC, which regulates WRM-1 nuclear export. We also show that APR-1 as well as PRY-1/Axin and Dishevelled homologs localize asymmetrically to the cortex. Our results suggest a model in which cortical WRM-1 recruits APR-1 to the anterior cortex before and during division, and the cortical APR-1 stimulates WRM-1 export from the anterior nucleus at telophase. Because beta-catenin and APC are localized to the cortex in many cell types in different species, our results suggest that these cortical proteins may regulate asymmetric divisions or Wnt signaling in other organisms as well. PMID:17276345
Hyperons in nuclear matter from SU(3) chiral effective field theory
International Nuclear Information System (INIS)
Brueckner theory is used to investigate the properties of hyperons in nuclear matter. The hyperon-nucleon interaction is taken from chiral effective field theory at next-to-leading order with SU(3) symmetric low-energy constants. Furthermore, the underlying nucleon-nucleon interaction is also derived within chiral effective field theory. We present the single-particle potentials of Λ and Σ hyperons in symmetric and asymmetric nuclear matter computed with the continuous choice for intermediate spectra. The results are in good agreement with the empirical information. In particular, our calculation gives a repulsive Σ-nuclear potential and a weak Λ-nuclear spin-orbit force. (orig.)
Hyperons in nuclear matter from SU(3) chiral effective field theory
Energy Technology Data Exchange (ETDEWEB)
Petschauer, S.; Kaiser, N. [Technische Universitaet Muenchen, Physik Department, Garching (Germany); Haidenbauer, J. [Institut fuer Kernphysik, Forschungszentrum Juelich, Institute for Advanced Simulation, Juelich Center for Hadron Physics, Juelich (Germany); Meissner, Ulf G. [Institut fuer Kernphysik, Forschungszentrum Juelich, Institute for Advanced Simulation, Juelich Center for Hadron Physics, Juelich (Germany); Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik and Bethe Center for Theoretical Physics, Bonn (Germany); Weise, W. [Technische Universitaet Muenchen, Physik Department, Garching (Germany); Villa Tambosi, ECT, Villazzano (Trento) (Italy)
2016-01-15
Brueckner theory is used to investigate the properties of hyperons in nuclear matter. The hyperon-nucleon interaction is taken from chiral effective field theory at next-to-leading order with SU(3) symmetric low-energy constants. Furthermore, the underlying nucleon-nucleon interaction is also derived within chiral effective field theory. We present the single-particle potentials of Λ and Σ hyperons in symmetric and asymmetric nuclear matter computed with the continuous choice for intermediate spectra. The results are in good agreement with the empirical information. In particular, our calculation gives a repulsive Σ-nuclear potential and a weak Λ-nuclear spin-orbit force. (orig.)
Interaction of nuclear radiation with matter
International Nuclear Information System (INIS)
This chapter of a textbook presents an overview of an important aspect of nuclear physics and nuclear chemistry. The effects of the interaction of nuclear radiation with substances are classified according to the acting particle, and the reacting constituents of the substance. The interactions of alpha radiation with matter (slowing down, scattering), of electron radiation with matter (slowing down, Cherenkov radiation, backscattering, absorption, annihilation), and of gamma radiation with matter (Compton effect, photoelectric effect, pair formation, absorption) are discussed. The reacting constituents are categorized as shell electrons, atomic nuclei, the Coulomb field of nuclei. In the complex interactions, the Auger effect and the photoelectron-induced bremsstrahlung is discussed. (R.P.)
Phi meson spectral moments and QCD condensates in nuclear matter
Gubler, Philipp
2016-01-01
A detailed analysis of the lowest two moments of the $\\phi$ meson spectral function in vacuum and nuclear matter is performed. The consistency is examined between the constraints derived from finite energy QCD sum rules and the spectra computed within an improved vector dominance model, incorporating the coupling of kanonic degrees of freedom with the bare $\\phi$ meson. In the vacuum, recent accurate measurements of the $e^+ e^- \\to K^+ K^-$ cross section allow us to determine the spectral function with high precision. In nuclear matter, the modification of the spectral function can be described by the interactions of the kaons from $\\phi \\rightarrow K\\bar{K}$ with the surrounding nuclear medium. This leads primarily to a strong broadening and an asymmetric deformation of the $\\phi$ meson peak structure. We confirm that, both in vacuum and nuclear matter, the zeroth and first moments of the corresponding spectral functions satisfy the requirements of the finite energy sum rules to a remarkable degree of accur...
Gamma-ray triangles: a possible signature of asymmetric dark matter in indirect searches
Ibarra, Alejandro; Molinaro, Emiliano; Pato, Miguel
2016-01-01
We introduce a new type of gamma-ray spectral feature, which we denominate gamma-ray triangle. This spectral feature arises in scenarios where dark matter self-annihilates via a chiral interaction into two Dirac fermions, which subsequently decay in flight into another fermion and a photon. The resulting photon spectrum resembles a sharp triangle and can be readily searched for in the gamma-ray sky. Using data from the Fermi-LAT and H.E.S.S. instruments, we find no evidence for such spectral feature and therefore set strong upper bounds on the corresponding annihilation cross section. A concrete realisation of a scenario yielding gamma-ray triangles consists of an asymmetric dark matter model where the dark matter particle carries lepton number. We show explicitly that this class of models can lead to intense gamma-ray spectral features, potentially at the reach of upcoming gamma-ray telescopes, opening a new window to explore asymmetric dark matter through indirect searches.
Skyrmions, dense matter and nuclear forces
International Nuclear Information System (INIS)
A simple introduction to a number of properties of Skyrme's chiral soliton model of baryons is given. Some implications of the model for dense matter and for nuclear interactions are discussed. (orig.)
Heavy Mesons in Nuclear Matter and Nuclei
International Nuclear Information System (INIS)
Heavy mesons in nuclear matter and nuclei are analyzed within different frameworks, paying a special attention to unitarized coupled-channel approaches. Possible experimental signatures of the properties of these mesons in matter are addressed, in particular in connection with the future FAIR facility at GSI
Nuclear matter with JISP16 NN interaction
Shirokov, A M; Vary, J P; Bogner, S K; Mazur, A I; Mazur, E A; Gogny, D
2014-01-01
Saturation properties of the JISP16 NN interaction are studied in symmetric nuclear matter calculations, with special attention paid to the convergence properties with respect to the number of partial waves. We also present results of pure neutron matter calculations with the JISP16 interaction.
Sigma meson and properties of nuclear matter
International Nuclear Information System (INIS)
We have calculated the saturation observables of symmetric nuclear matter and nuclear symmetry energy in the framework of Brueckner-Hartree-Fock (BHF) formalism with Bonn-B potential as two-body interaction, including modification of hadronic parameter inside nuclear medium. We have found that it is possible to understand all the saturation observables of symmetric nuclear matter by incorporating in-medium modification of the parameters of sigma meson alone. Linear density dependent reduction of σ-nucleon coupling constant by about 6.8% and density independent reduction σ-meson mass by about 3.5% is sufficient to understand nuclear matter saturation observables. We find with the calculated symmetry energy that neutron skin thickness of 208Pb is 0.20 fm and the radius of 1.4 solar mass neutron stars as 11.98 ± 0.75 km. (author)
Dense nuclear matter and symmetry energy in strong magnetic fields
International Nuclear Information System (INIS)
The properties of nuclear matter in the presence of a strong magnetic field, including the density-dependent symmetry energy, the chemical composition and spin polarizations, are investigated in the framework of the relativistic mean field models FSUGold. The anomalous magnetic moments (AMM) of the particles and the nonlinear isoscalar–isovector coupling are included. It is found that the parabolic isospin dependence of the energy per nucleon of asymmetric nuclear matter remains valid for the values of magnetic field below 105Bce, Bce=4.414×1013 G being the electron critical field. Accordingly, the symmetry energy can be obtained by the difference of the energy per nucleon in pure neutron matter and that in symmetric matter. The symmetry energy, which is enhanced by the presence of the magnetic field, significantly affects the chemical composition and the proton polarization. The effects of the AMM of each component on the energy per nucleon, symmetry energy, chemical composition and spin polarization are discussed in detail
Properties of nuclear matter from macroscopic-microscopic mass formulas
Wang, Ning; Ou, Li; Zhang, Yingxun
2015-01-01
Based on the standard Skyrme energy density functionals together with the extended Thomas-Fermi approach, the properties of symmetric and asymmetric nuclear matter represented in two macroscopic-microscopic mass formulas: Lublin-Strasbourg nuclear drop energy (LSD) formula and Weizs\\"acker-Skyrme (WS*) formula, are extracted through matching the energy per particle of finite nuclei. For LSD and WS*, the obtained incompressibility coefficients of symmetric nuclear matter are $K_\\infty=230 \\pm 11$ MeV and $235\\pm 11$ MeV, respectively. The slope parameter of symmetry energy at saturation density is $L=41.6\\pm 7.6$ MeV for LSD and $51.5\\pm 9.6$ MeV for WS*, respectively, which is compatible with the liquid-drop analysis of Lattimer and Lim [ApJ. \\textbf{771}, 51 (2013)]. The density dependence of the mean-field isoscalar and isovector effective mass, and the neutron-proton effective masses splitting for neutron matter are simultaneously investigated. The results are generally consistent with those from the Skyrm...
Properties of nuclear matter from macroscopic-microscopic mass formulas
Wang, Ning; Liu, Min; Ou, Li; Zhang, Yingxun
2015-12-01
Based on the standard Skyrme energy density functionals together with the extended Thomas-Fermi approach, the properties of symmetric and asymmetric nuclear matter represented in two macroscopic-microscopic mass formulas: Lublin-Strasbourg nuclear drop energy (LSD) formula and Weizsäcker-Skyrme (WS*) formula, are extracted through matching the energy per particle of finite nuclei. For LSD and WS*, the obtained incompressibility coefficients of symmetric nuclear matter are K∞ = 230 ± 11 MeV and 235 ± 11 MeV, respectively. The slope parameter of symmetry energy at saturation density is L = 41.6 ± 7.6 MeV for LSD and 51.5 ± 9.6 MeV for WS*, respectively, which is compatible with the liquid-drop analysis of Lattimer and Lim [4]. The density dependence of the mean-field isoscalar and isovector effective mass, and the neutron-proton effective masses splitting for neutron matter are simultaneously investigated. The results are generally consistent with those from the Skyrme Hartree-Fock-Bogoliubov calculations and nucleon optical potentials, and the standard deviations are large and increase rapidly with density. A better constraint for the effective mass is helpful to reduce uncertainties of the depth of the mean-field potential.
Clusters in nuclear matter and Mott points
Rpke, G
2015-01-01
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.
Past and present of nuclear matter
International Nuclear Information System (INIS)
The subject of nuclear matter is interesting for many fields of physics ranging from condensed matter to lattice QCD. Knowing its properties is important for our understanding of neutron stars, supernovae and cosmology. Experimentally, we have the most precise information on ground state nuclear matter from the mass formula and from the systematics of monopole vibrations. This gives us the ground state density, binding energy and the compression modulus k at ground state density. However, those methods can not be extended towards the regime we are most interested in, the regime of high density and high temperature. Additional information can be obtained from the observation of neutron stars and of supernova explosions. In both cases information is limited by the rare events that nature provides for us. High energy heavy ion collisions, on the other hand, allow us to perform controlled experiments in the laboratory. For a very short period in time we can create a system that lets us study nuclear matter properties. Density and temperature of the system depend on the mass of the colliding nuclei, on their energy and on the impact parameter. The system created in nuclear collisions has at best about 200 constituents not even close to infinite nuclear matter, and it lasts only for collision times of ? 10-22sec, not an ideal condition for establishing any kind of equilibrium. Extended size and thermal and chemical equilibrium, however, axe a priori conditions of nuclear matter. As a consequence we need realistic models that describe the collision dynamics and non-equilibrium effects in order to relate experimental observables to properties of nuclear matter. The study of high energy nuclear collisions started at the Bevalac. I will try to summarize the results from the Bevalac studies, the highlights of the continuing program, and extension to higher energies without claiming to be complete
Describing Nuclear Matter with Effective Field Theories
International Nuclear Information System (INIS)
An accurate description of nuclear matter starting from free-space nuclear forces has been an elusive goal. The complexity of the system makes approximations inevitable, so the challenge is to find a consistent truncation scheme with controlled errors. The virtues of an effective field theory approach to this problem are discussed
The single particle potential in nuclear matter
International Nuclear Information System (INIS)
The energy dependent real part of the optical potential of particles and holes in nuclear matter is calculated from a realistic nuclear hamiltonian that explains the nucleon-nucleon scattering data and equilibrium properties of nuclear matter. The vibrational method is used with Fermi-hypernetted and single-operator-chain summation techniques. The results are comparable with empirical Woods-Saxon well depths at energies approx. < 150 MeV. At higher energies the potential has a density dependence suggesting a wine-bottle shaped nucleon-nucleus potential. (orig.)
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 πN interaction before reaching a final conclusion about nonrelativistic treatment of nuclear matter
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. We find that the role of the tensor force in the saturation mechanism is substantially reduced compared to its dominant role in a usual nonrelativistic treatment. We show that the damping of derivative-coupled OPEP is actually due to the decrease of M*/M with increasing density. We point 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. We suggest an examination of the feasibility of using pseudoscalar coupled πN interaction before reaching a final conclusion about nonrelativistic treatment of nuclear matter. (author)
Relativity Damps OPEP in Nuclear Matter
Banerjee, M K
1998-01-01
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. We find that the role of the tensor force in the saturation mechanism is substantially reduced compared to its dominant role in a usual nonrelativistic treatment. We show that the damping of derivative-coupled OPEP is actually due to the decrease of $M^*/M$ with increasing density. We point 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. We suggest an examination of the feasibility of using pseudoscalar coupled $\\pi$N interaction before reaching a final conclusion about nonrelativistic treatment of nuclear matter.
Relativity Damps OPEP in Nuclear Matter
Banerjee, Manoj K.
1998-09-01
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. We find that the role of the tensor force in the saturation mechanism is substantially reduced compared to its dominant role in a usual nonrelativistic treatment. We show that the damping of derivative-coupled OPEP is actually due to the decrease of M*/M with increasing density. We point 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. We suggest an examination of the feasibility of using pseudoscalar coupled πN interaction before reaching a final conclusion about nonrelativistic treatment of nuclear matter.
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
A possible indication of momentum-dependent asymmetric dark matter in the Sun
Vincent, Aaron C; Serenelli, Aldo
2014-01-01
Broad disagreement persists between helioseismological observables and predictions of solar models computed with the latest surface abundances. Here we show that most of these problems can be solved by the presence of asymmetric dark matter coupling to nucleons as the square of the momentum $q$ exchanged in the collision. We compute neutrino fluxes, small frequency separations, surface helium abundances, sound speed profiles and convective zone depths for a number of models, showing more than a $6\\sigma$ preference for $q^2$ models over others, and over the Standard Solar Model. The preferred mass (3 GeV) and reference dark matter-nucleon cross-section ($10^{-37}$ cm$^2$ at $q_0 = 40$ MeV) are within the region of parameter space allowed by both direct detection and collider searches.
Isospin effect on elliptical flow for mass asymmetric nuclear collisions
International Nuclear Information System (INIS)
Collective flow is the measure of the transverse motion imparted to the particles and fragments during the collision of two nuclei. Among the different kind of collective flow, elliptical flow enjoys the special status due to its sensitivity towards reaction dynamics. The azimuthal asymmetric emission pattern in which particles found to be preferentially emitted perpendicular to the reaction plane describes the elliptical flow. Elliptical flow has been studied extensively at BEVALAC, SIS and AGS energies. The present work is carried out to study the effect of Coulomb potential on the transverse momentum dependence of elliptical flow by taking mass asymmetric collisions. The study is performed within the frame work of IQMD model
Nucleon-nucleon interaction in nuclear matter
International Nuclear Information System (INIS)
The effective two-body potential in nuclear matter due to the two-pion-exchange three-body force can be expressed such that it arises due to a change in the pion propagator pertaining to the one-pion-exchange potential (OPEP). It is shown that the modified propagator can be approximated by [(1 - α)(q2 + μ'2)]-1 where μ' = μ(1 - α)sup(-1/2), μ is the pion mass, and α is a constant which is roughly proportional to the nuclear matter density. For example, α asymptotically equals 0.3 for the normal density. The modified OPEP is then obtained by scaling the OPEP in vacuum. It is suggested that other parts of the NN potential, e.g., the two-pion-exchange part, are also modified by the same mechanism, and hence the NN interaction in nuclear matter could be strongly density-dependent. (auth.)
Nuclear matter with three-body forces
International Nuclear Information System (INIS)
Full text: We present spectral calculations of nuclear matter properties, with three-body forces included in the in-medium T-matrix equations. The thermodynamic observables are computed for symmetric and pure neutron matter, and estimations for the density dependence of the symmetry energy are obtained. We also investigate the influence of three-body forces on the single-particle properties, discussing spectral functions, self-energies and effective masses. (author)
Wnt regulates spindle asymmetry to generate asymmetric nuclear ?-catenin in C. elegans.
Sugioka, Kenji; Mizumoto, Kota; Sawa, Hitoshi
2011-09-16
Extrinsic signals received by a cell can induce remodeling of the cytoskeleton, but the downstream effects of cytoskeletal changes on gene expression have not been well studied. Here, we show that during telophase of an asymmetric division in C. elegans, extrinsic Wnt signaling modulates spindle structures through APR-1/APC, which in turn promotes asymmetrical nuclear localization of WRM-1/?-catenin and POP-1/TCF. APR-1 that localized asymmetrically along the cortex established asymmetric distribution of astral microtubules, with more microtubules found on the anterior side. Perturbation of the Wnt signaling pathway altered this microtubule asymmetry and led to changes in nuclear WRM-1 asymmetry, gene expression, and cell-fate determination. Direct manipulation of spindle asymmetry by laser irradiation altered the asymmetric distribution of nuclear WRM-1. Moreover, laser manipulation of the spindles rescued defects in nuclear POP-1 asymmetry in wnt mutants. Our results reveal a mechanism in which the nuclear localization of proteins is regulated through the modulation of microtubules. PMID:21925317
Wanted! Nuclear Data for Dark Matter Astrophysics
Gondolo, Paolo
2013-01-01
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 ...
Phase transitions in high density nuclear matter
International Nuclear Information System (INIS)
A method for the description of spin-isospin phase transitions in nuclear matter is developed. It allows a complete description of the pion condensation phase transition in the framework of the Landau-Migdal Fermi liquid theory. The equation of the order parameters is derived and the condensation energy is calculated. We study the influence of pion condensation on the nuclear equation of state and the temperature dependence of pion condensation. Finally the phase transition from nucleon to quark matter is investigated. The relevance of the color degree of freedom is discussed. (orig.)
Nuclear matter theory. [Realistic forces, review
Energy Technology Data Exchange (ETDEWEB)
Negele, J.W.
1977-01-01
Recent advances in variational and perturbative theories are surveyed which offer genuine promise that nuclear matter will soon become a viable tool for investigating nuclear interactions. The basic elements of the hypernetted chain expansion for Jastrow variational functions are briefly reviewed, and comparisons of variational and perturbative results for a series of increasingly complicated systems are presented. Prospects for investigating realistic forces are assessed and the unresolved, open problems are summarized.
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.)
Nuclear matter with constituent meson quanta
International Nuclear Information System (INIS)
The authors discuss some nonperturbative techniques of field theory, where they dress nuclear matter as a whole with off-mass-shell pions. Here s-wave pion pairs simulate the effect of σ-meson of the mean field approach of Walecka. The signatures are in agreement with earlier results along with new physical insight
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
Antikaons in nuclei and dense nuclear matter
Ramos, A.; Hirenzaki, S.; Kamalov, S. S.; Kuo, T. T. S.; Okumura, Y.; Oset, E.; Polls, A.; Toki, H; Tolos, L.
2001-01-01
We present recent progress on the properties of antikaons in nuclei and dense nuclear matter as obtained from two {\\bar K}N interaction models: one based on the lowest-order meson-baryon chiral lagrangian and the other derived from a meson-exchange picture.
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)
Exploring dense nuclear matter with nuclear collisions
International Nuclear Information System (INIS)
An overview of the current status of the field of relativistic heavy-ion collisions is given with a focus on experimental results from both the AGS and the CERN SpS programs. These programs are devoted to a search for new physical phenomena that might be present at the extreme baryon densities that are expected to be produced in heavy-ion collisions at AGS and SpS energies. One such phenomenon which has received significant theoretical attention in recent years is the QCD phase transition from hadronic matter to quark-gluon plasma. Although there is currently no unambiguous experimental evidence for QGP formation in heavy-ion collisions, the presented experimental data will show that there are several experimental observables showing non-trivial changes between p- p and heavy-ion collisions. Systematic measurements are now being made that will hopefully allow us to determine whether these observations result from QGP formation, from 'background' hadronic processes, or from completely new physical phenomena. (author)
Controllable Asymmetric Matter-wave Beam Splitter and Ring Potential on an Atom Chip
Kim, S J; Gang, S T; Anderson, D; Kim, J B
2015-01-01
We have constructed an asymmetric matter-wave beam splitter and a ring potential on an atom chip with Bose-Einstein condensates using radio-frequency dressing. By applying rf-field parallel to the quantization axis in the vicinity of the static trap minima added to perpendicular rf-fields, versatile controllability on the potentials is realized. Asymmetry of the rf-induced double well is manipulated without discernible displacement of the each well along horizontal and vertical direction. Formation of an isotropic ring potential on an atom chip is achieved by compensating the gradient due to gravity and inhomogeneous coupling strength. In addition, position and rotation velocity of a BEC along the ring geometry are controlled by the relative phase and the frequency difference between the rf-fields, respectively.
Chen, Shao-Long
2015-01-01
The inverse seesaw mechanism provides an attractive approach to generate small neutrino mass, which origins from a tiny $U(1)_L$ breaking. In this paper, we work in the supersymmetric version of this mechanism, where the singlet-like sneutrino could be an asymmetric dark matter (ADM) candidate in the maximally $U(1)_{L}$ symmetric limit. However, even a tiny $\\delta m$, the mass splitting between sneutrino and anti-sneutrino as a result of the tiny $U(1)_{L}$ breaking effect, could lead to fast oscillation between sneutrino and anti-sneutrino and thus spoils the ADM scenario. We study the evolution of this oscillation and find that a weak scale sneutrino, which tolerates a relatively larger $\\delta m\\sim 10^{-5}$ eV, is strongly favored. We also investigate possible natural ways to realize that small $\\delta m$ in the model.
Probing Cold Dense Nuclear Matter
Subedi, R; Monaghan, P; Anderson, B D; Aniol, K; Annand, J; Arrington, J; Benaoum, H; Benmokhtar, F; Bertozzi, W; Boeglin, W; Chen, J -P; Choi, Seonho; Cisbani, E; Craver, B; Frullani, S; Garibaldi, F; Gilad, S; Gilman, R; Glamazdin, O; Hansen, J -O; Higinbotham, D W; Holmstrom, T; Ibrahim, H; Igarashi, R; De Jager, C W; Jans, E; Jiang, X; Kaufman, L; Kelleher, A; Kolarkar, A; Kumbartzki, G; LeRose, J J; Lindgren, R; Liyanage, N; Margaziotis, D J; Markowitz, P; Marrone, S; Mazouz, M; Meekins, D; Michaels, R; Moffit, B; Perdrisat, C F; Piasetzky, E; Potokar, M; Punjabi, V; Qiang, Y; Reinhold, J; Ron, G; Rosner, G; Saha, A; Sawatzky, B; Shahinyan, A; Širca, S; Slifer, K; Solvignon, P; Sulkosky, V; Urciuoli, G; Voutier, E; Watson, J W; Weinstein, L B; Wojtsekhowski, B; Wood, S; Zheng, X -C; Zhu, L; 10.1126/science.1156675
2009-01-01
The protons and neutrons in a nucleus can form strongly correlated nucleon pairs. Scattering experiments, where a proton is knocked-out of the nucleus with high momentum transfer and high missing momentum, show that in 12C the neutron-proton pairs are nearly twenty times as prevalent as proton-proton pairs and, by inference, neutron-neutron pairs. This difference between the types of pairs is due to the nature of the strong force and has implications for understanding cold dense nuclear systems such as neutron stars.
Probing Cold Dense Nuclear Matter
Energy Technology Data Exchange (ETDEWEB)
Subedi, Ramesh; Shneor, R.; Monaghan, Peter; Anderson, Bryon; Aniol, Konrad; Annand, John; Arrington, John; Benaoum, Hachemi; Benmokhtar, Fatiha; Bertozzi, William; Boeglin, Werner; Chen, Jian-Ping; Choi, Seonho; Cisbani, Evaristo; Craver, Brandon; Frullani, Salvatore; Garibaldi, Franco; Gilad, Shalev; Gilman, Ronald; Glamazdin, Oleksandr; Hansen, Jens-Ole; Higinbotham, Douglas; Holmstrom, Timothy; Ibrahim, Hassan; Igarashi, Ryuichi; De Jager, Cornelis; Jans, Eddy; Jiang, Xiaodong; Kaufman, Lisa; Kelleher, Aidan; Kolarkar, Ameya; Kumbartzki, Gerfried; LeRose, John; Lindgren, Richard; Liyanage, Nilanga; Margaziotis, Demetrius; Markowitz, Pete; Marrone, Stefano; Mazouz, Malek; Meekins, David; Michaels, Robert; Moffit, Bryan; Perdrisat, Charles; Piasetzky, Eliazer; Potokar, Milan; Punjabi, Vina; Qiang, Yi; Reinhold, Joerg; Ron, Guy; Rosner, Guenther; Saha, Arunava; Sawatzky, Bradley; Shahinyan, Albert; Sirca, Simon; Slifer, Karl; Solvignon, Patricia; Sulkosky, Vince; Sulkosky, Vincent; Sulkosky, Vince; Sulkosky, Vincent; Urciuoli, Guido; Voutier, Eric; Watson, John; Weinstein, Lawrence; Wojtsekhowski, Bogdan; Wood, Stephen; Zheng, Xiaochao; Zhu, Lingyan
2008-06-01
The protons and neutrons in a nucleus can form strongly correlated nucleon pairs. Scattering experiments, in which a proton is knocked out of the nucleus with high-momentum transfer and high missing momentum, show that in carbon-12 the neutron-proton pairs are nearly 20 times as prevalent as proton-proton pairs and, by inference, neutron-neutron pairs. This difference between the types of pairs is due to the nature of the strong force and has implications for understanding cold dense nuclear systems such as neutron stars.
The public and nuclear matters
International Nuclear Information System (INIS)
The nuclear industry has an image problem and is facing a major crisis of public confidence. The solution lies not merely in better public relations and advertising campaigns, but in a fundamental reassessment of electricity management, a comprehensive re-examination of the economics of electricity use and generation and, in all probability, a shift towards more public-friendly reactor designs. Over the next decade the industry faces two great forces: the power of public opinion and the momentum of inherent technological advance. Somehow these two elements have to be guided so that they complement each other. This article aims to show how this might be achieved. (author)
The microscopic approach to nuclear matter and neutron star matter
International Nuclear Information System (INIS)
We review a variety of theoretical and experimental investigations aimed at improving our knowledge of the nuclear matter equation of state. Of particular interest are nuclear matter extreme states in terms of density and/or isospin asymmetry. The equation of state of matter with unequal concentrations of protons and neutrons has numerous applications. These include heavy-ion collisions, the physics of rare, short-lived nuclei and, on a dramatically different scale, the physics of neutron stars. The "common denominator" among these (seemingly) very different systems is the symmetry energy, which plays a crucial role in both the formation of the neutron skin in neutron-rich nuclei and the radius of a neutron star (a system 18 orders of magnitude larger and 55 orders of magnitudes heavier). The details of the density dependence of the symmetry energy are not yet sufficiently constrained. Throughout this article, our emphasis will be on the importance of adopting a microscopic approach to the many-body problem, which we believe to be the one with true predictive power. (author)
Towards Nuclear Physics of OHe Dark Matter
Khlopov, Maxim Yu; Soldatov, Evgeny Yu
2011-01-01
The nonbaryonic dark matter of the Universe can consist of new stable charged particles, bound in heavy "atoms" by ordinary Coulomb interaction. If stable particles $O^{--}$ with charge -2 are in excess over their antiparticles (with charge +2), the primordial helium, formed in Big Bang Nucleosynthesis, captures all $O^{--}$ in neutral "atoms" of O-helium (OHe). Interaction with nuclei plays crucial role in the cosmological evolution of OHe and in the effects of these dark atoms as nuclear interacting dark matter. Slowed down in terrestrial matter OHe atoms cause negligible effects of nuclear recoil in underground detectors, but can experience radiative capture by nuclei. Local concentration of OHe in the matter of detectors is rapidly adjusted to the incoming flux of cosmic OHe and possess annual modulation due to Earth's orbital motion around the Sun. The potential of OHe-nucleus interaction is determined by polarization of OHe by the Coulomb and nuclear force of the approaching nucleus. Stark-like effect b...
Consequences of DM/antiDM oscillations for asymmetric WIMP dark matter
International Nuclear Information System (INIS)
Assuming the existence of a primordial asymmetry in the dark sector, a scenario usually dubbed Asymmetric Dark Matter (aDM), we study the effect of oscillations between dark matter and its antiparticle on the re-equilibration of the initial asymmetry before freeze-out, which enable efficient annihilations to recouple. We calculate the evolution of the DM relic abundance and show how oscillations re-open the parameter space of aDM models, in particular in the direction of allowing large (WIMP-scale) DM masses. A typical WIMP with a mass at the EW scale ( ∼ 100 GeV – 1 TeV) presenting a primordial asymmetry of the same order as the baryon asymmetry naturally gets the correct relic abundance if the DM-number-violating Δ(DM) = 2 mass term is in the ∼ meV range. The re-establishment of annihilations implies that constraints from the accumulation of aDM in astrophysical bodies are evaded. On the other hand, the ordinary bounds from BBN, CMB and indirect detection signals on annihilating DM have to be considered
Wanted! Nuclear Data for Dark Matter Astrophysics
International Nuclear Information System (INIS)
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
From QCD to nuclear matter saturation
International Nuclear Information System (INIS)
We discuss a relativistic chiral theory of nuclear matter with σ and ω exchange using a formulation of the σ model in which all the chiral constraints are automatically fulfilled. We establish a relation between the nuclear response to the scalar field and the QCD one which includes the nucleonic parts. It allows a comparison between nuclear and QCD information. Going beyond the mean field approach we introduce the effects of the pion loops supplemented by the short-range interaction. The corresponding Landau-Migdal parameters are taken from spin-isospin physics results. The parameters linked to the scalar meson exchange are extracted from lattice QCD results. These inputs lead to a reasonable description of the saturation properties, illustrating the link between QCD and nuclear physics. We also derive from the corresponding equation of state the density dependence of the quark condensate and of the QCD susceptibilities. (authors)
Nuclear dynamics of mass asymmetric systems at balance energy
International Nuclear Information System (INIS)
In the search of nuclear equation of state as well as of nuclear interactions and forces, collective transverse flow has been found to be of immense importance. At low incident energies, the collective transverse flow is dominated by attractive interactions and the flow is expected to be negative, while at high incident energies, the flow is dominated by nucleon-nucleon repulsive interactions and is expected to be positive. While going from low to high incident energies, collective transverse flow vanishes at a particular value of energy, which is termed as Balance Energy (Ebal). The Ebal has been reported to be of significance toward the understanding of nuclear interactions and related dynamics
Nucleons interacting with excited nuclear matter
International Nuclear Information System (INIS)
Full text: In microscopic approaches of precompound reactions the dependence of the optical potential on the excitation is still an open question, which might heal some deficiencies of present day calculations. For the interesting energy regime the nuclear matter approach is well suited, which is based on the g-matrix obtained from Bethe-Goldstone equation. In order to account for the excitation of nuclear matter a simple model of excitation has been developed and a correspondingly refined Pauli-operator has been formulated. The dependence of the g-matrix on the excitation as well as on the incident energy is studied. In addition, the impact of excitation on optical potentials and cross sections is discussed. (author)
Nuclear matter with scalar-vector interactions
Energy Technology Data Exchange (ETDEWEB)
Moncada, A.; Scholtz, F.G.; Hahne, F.J.W. (Institute of Theoretical Physics, University of Stellenbosch, Stellenbosch 7600 (South Africa))
1994-09-01
The properties of cold nuclear matter are investigated in a class of nonlinear mean field [sigma]-[omega] theories which includes a density dependence of the meson parameters. This dependence can be both explicit and implicit through the effective nucleon mass. We apply the theory to the case of an interaction between the scalar and the vector mesons and investigate the properties of neutron stars using the resulting equation of state.
Nuclear matter with scalar-vector interactions
International Nuclear Information System (INIS)
The properties of cold nuclear matter are investigated in a class of nonlinear mean field σ-ω theories which includes a density dependence of the meson parameters. This dependence can be both explicit and implicit through the effective nucleon mass. We apply the theory to the case of an interaction between the scalar and the vector mesons and investigate the properties of neutron stars using the resulting equation of state
Nuclear matter theory: a status report
International Nuclear Information System (INIS)
Recent years have brought considerable improvement in the quality of both diagrammatic and variational many-body techniques. There appears to be general agreement that realistic NN potentials give a reasonable binding energy but an equilibrium density that is some 75% larger than the empirical value. Both conventional and chiral models of genuine manybody forces offer mechanisms for removing this discrepancy with each providing a simple picture for the required additional attraction for /rho/ 0. Neither approach is presently able to make a priori estimates of the magnitude of this effect with the delicacy required by the nuclear matter problem. Nor is it clear how to merge these pictures. We should not anticipate quick answers to these questions. One suitable interim strategy is to assume that many-body forces of the form suggested by either conventional or chiral pictures are responsible for the remaining discrepancy and to adjust parameters in such model many-body forces to restore agreement between theory and experiment. This might seem to be a summary dismissal of the standard nuclear matter problem. It should rather be regarded as revealing the next and richer layer of the nuclear matter problem
Charge-dependent directed flow in asymmetric nuclear collisions
Voronyuk, V; Voloshin, S A; Cassing, W
2014-01-01
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...
Anatomy of symmetry energy of dilute nuclear matter
De, J N; Agrawal, B K
2010-01-01
The symmetry energy coefficients of dilute clusterized nuclear matter are evaluated in the $S$-matrix framework. Employing a few different definitions commonly used in the literature for uniform nuclear matter, it is seen that the different definitions lead to perceptibly different results for the symmetry coefficients for dilute nuclear matter. They are found to be higher compared to those obtained for uniform matter in the low density domain. The calculated results are in reasonable consonance with those extracted recently from experimental data.
Hot dense nuclear matter and its disassembly
International Nuclear Information System (INIS)
Transient hot and compressed nuclear matter created in energetic nuclear collisions responds to the perturbation through a sudden expansion and subsequent emission of a large number of light particles as well as intermediate mass fragments (IMFs). These particles carry the imprint of the thermal energy as well as the collective flow energy of the disassembling system. The effect of radial collective flow on the element distribution in prompt nuclear multifragmentation is studied in a quantum statistical model. The production of very light particles is seen to increase with flow energy at all temperatures. The yield of IMFs is enhanced only at relatively low temperatures and suppressed at high temperatures. The IMF-IMF correlation functions have also been studied and it is seen that the peak-structure of the functions are washed out with increasing flow energy. (author). 18 refs., 5 figs
Heavy Vector and Axial-Vector Mesons in Hot and Dense Asymmetric Strange Hadronic Matter
Kumar, Arvind
2015-01-01
We calculate the effects of finite density and temperature of isospin asymmetric strange hadronic matter, for different strangeness fractions, on the in-medium properties of vector $\\left( D^{\\ast}, D_{s}^{\\ast}, B^{\\ast}, B_{s}^{\\ast}\\right)$ and axial-vector $\\left( D_{1}, D_{1s}, B_{1}, B_{1s}\\right)$ mesons, using chiral hadronic SU(3) model and QCD sum rules. We focus on the evaluation of in-medium mass-shift and shift in decay constant of above vector and axial-vector mesons. In QCD sum rule approach, the properties, e.g., the masses and decay constants of vector and axial-vector mesons are written in terms of quark and gluon condensates. These quark and gluon condensates are evaluated in the present work within chiral SU(3) model, through the medium modification of, scalar-isoscalar fields $\\sigma$ and $\\zeta$, the scalar-isovector field $\\delta$ and scalar dilaton field $\\chi$, in the strange hadronic medium which includes both nucleons as well as hyperons. As we shall see in detail, the masses and de...
Asymmetric Dark Matter in the Sun and the Diphoton Excess at the LHC
Dev, P S Bhupal
2015-01-01
Recently, ATLAS and CMS have observed an excess in the diphoton channel with respect to the Standard Model background, with resonance at an invariant mass of about 750 GeV. At the same time, it has been recently pointed out that a momentum-dependent cross section for asymmetric Dark Matter (DM) interacting with nucleons can explain the disagreement between helioseismological observables and the predictions of solar models. In this letter we consider the minimal model for generating such momentum-dependent cross section, which consists of a scalar and a pseudoscalar mediator, in addition to the DM Dirac fermion. Remarkably, the pseudoscalar can be taken at a mass of 750 GeV, explaining quantitatively at the same time the observed diphoton excess and the solar anomaly. In this framework, the total width of the resonance is naturally large, as suggested by the ATLAS experiment. The model predicts the existence of a new scalar in the GeV range, interacting with quarks, and observable t-tbar and dijet signals in t...
International Nuclear Information System (INIS)
A full (3+1)-dimensional calculation using Lagrangian hydrodynamics is proposed for relativistic nuclear collisions. This calculation enables us to evaluate the anisotropic flow of the hadronic matter which appears in non-central and/or asymmetrical relativistic nuclear collisions. Applying hydrodynamical calculations to the deformed uranium collisions in the AGS energy region, we discuss the nature of the space-time structure and particle distributions in detail. (orig.)
Kaon dynamics in dense nuclear matter
International Nuclear Information System (INIS)
In this thesis a list of cross sections concerning the kaons and antikaons production, has been presented. A new method for the parametrisation of particles rescattering cross sections, based on the neural networks has been developed. Because of the influence of the nuclear matter on kaons properties, the effect of the optical potential parameters has been studied. In particular a term has been added to the vector part of this potential to determine the relative importance of this part compared to the scalar part. A new parametrisation of the resonance lifetime has been proposed. (A.L.B.)
Mass shift of -meson in nuclear matter
Indian Academy of Sciences (India)
J R Morones-Ibarra; Mónica Menchaca Maciel; Ayax Santos-Guevara; Felipe Robledo Padilla
2013-03-01
The propagation of -meson in nuclear matter is studied in the Walecka model, by assuming that the sigma couples to a pair of nucleon–antinucleon states and to particle–hole states. The in-medium effect of - mixing is also studied. For completeness, the coupling of sigma to two virtual pions was also considered. It is found that the -meson mass decreases with respect to its value in vacuum and that the contribution of the - mixing effect on the mass shift is relatively small.
Relativity Damps OPEP in Nuclear Matter
Banerjee, Manoj K.
1998-01-01
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. We find that the role of the tensor force in the saturation mechanism is substantially reduced compared to its dominant role in a usual nonrelativistic treatment. We show that the damping of derivative-coupled OPEP is actually due to the decrease of $M^*/M$ with increasing density. We point out that if derivative-coupled OPEP...
Hadronization measurements in cold nuclear matter
Energy Technology Data Exchange (ETDEWEB)
Dupre, Raphael [Inst. de Physique Nucleaire (IPN), Orsay (France). et al.
2015-05-01
Hadronization is the non-perturbative process of QCD by which partons become hadrons. It has been studied at high energies through various processes, we focus here on the experiments of lepto-production of hadrons in cold nuclear matter. By studying the dependence of observables to the atomic number of the target, these experimentscan give information on the dynamic of the hadronization at the femtometer scale. In particular, we will present preliminary results from JLab Hall B (CLAS collaboration), which give unprecedented statistical precision. Then, we will present results of a phenomenological study showing how HERMES data can be described with pure energyloss models.
Nuclear target effect on dark matter detection rate
Bednyakov, V. A.; Simkovic, F.
2005-01-01
Expected event rates for a number of dark matter nuclear targets were calculated in the effective low-energy minimal supersymmetric standard model, provided the lightest neutralino is the dark matter Weakly Interacting Massive Particle (WIMP). These calculations allow direct comparison of sensitivities of different dark matter detectors to intermediate mass WIMPs expected from the measurements of the DArk MAtter (DAMA) experiment.
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 presented and discussed 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. (author)
Particle-hole states in nuclear matter
International Nuclear Information System (INIS)
This work deals with the collective excitations in nuclear matter, from the point of view of the TDA approximation. Our calculations involved the construction of a Hamiltonian, expressed as a matrix in the space of particle-hole excitations with a given momentum transfer. We used in this Hamiltonian an average single nucleon potential, and (in some cases) an effective interaction obtained for the potential HEA in the relativistic Brueckner-Hartree Fock theory. The eigenvectors of the TDA-Hamiltonian were used to compute the strength of the collective response of nuclear matter to external probes. Our results, succinctly described in the last section, are summarized in a set of figures at the end of this monograph. The specific form of the TDA equations that we used, and the procedure to calculate the degree of collectivity of the solutions, is studied in detail in the fifth chapter. A derivation of the TDA equations, and a discussion of the solutions for a separable potential, is given in the fourth chapter. The structure of a non-relativistic potential for a system of two nucleons is examined in the third chapter, in several representations. On the other hand, the particle-hole states relevant to our discussions on the TDA equations are introduced in the first two chapters
Incomprehensibility in finite nuclei and nuclear matter
Stone, J R; Moszkowski, S A
2014-01-01
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,...
Unmasking the nuclear matter equation of state
Piekarewicz, J
2004-01-01
Accurately calibrated (or ``best fit'') relativistic mean-field models are used to compute the distribution of isoscalar monopole strength in 90Zr and 208Pb, and the isovector dipole strength in 208Pb using a continuum random-phase-approximation approach. It is shown that the distribution of isoscalar monopole strength in 208Pb--but not in 90Zr--is sensitive to the density dependence of the symmetry energy. This sensitivity hinders the extraction of the compression modulus of symmetric nuclear matter from the isoscalar giant monopole resonance (ISGMR) in 208Pb. Thus, one relies on 90Zr, a nucleus with both a small neutron-proton asymmetry and a well developed ISGMR peak, to constrain the compression modulus of symmetric nuclear matter to the range K=(248 +/- 6) MeV. In turn, the sensitivity of the ISGMR in 208Pb to the density dependence of the symmetry energy is used to constrain its neutron skin to the range Rn-Rp<=0.22 fm. The impact of this result on the enhanced cooling of neutron stars is briefly add...
Self-interacting asymmetric dark matter coupled to a light massive dark photon
International Nuclear Information System (INIS)
Dark matter (DM) with sizeable self-interactions mediated by a light species offers a compelling explanation of the observed galactic substructure; furthermore, the direct coupling between DM and a light particle contributes to the DM annihilation in the early universe. If the DM abundance is due to a dark particle-antiparticle asymmetry, the DM annihilation cross-section can be arbitrarily large, and the coupling of DM to the light species can be significant. We consider the case of asymmetric DM interacting via a light (but not necessarily massless) Abelian gauge vector boson, a dark photon. In the massless dark photon limit, gauge invariance mandates that DM be multicomponent, consisting of positive and negative dark ions of different species which partially bind in neutral dark atoms. We argue that a similar conclusion holds for light dark photons; in particular, we establish that the multi-component and atomic character of DM persists in much of the parameter space where the dark photon is sufficiently light to mediate sizeable DM self-interactions. We discuss the cosmological sequence of events in this scenario, including the dark asymmetry generation, the freeze-out of annihilations, the dark recombination and the phase transition which gives mass to the dark photon. We estimate the effect of self-interactions in DM haloes, taking into account this cosmological history. We place constraints based on the observed ellipticity of large haloes, and identify the regimes where DM self-scattering can affect the dynamics of smaller haloes, bringing theory in better agreement with observations. Moreover, we estimate the cosmological abundance of dark photons in various regimes, and derive pertinent bounds
Dark Matter Particle Spectroscopy at the LHC: Generalizing M(T2) to Asymmetric Event Topologies
Energy Technology Data Exchange (ETDEWEB)
Konar, Partha; /Florida U.; Kong, Kyoungchul; /SLAC; Matchev, Konstantin T.; Park, Myeonghun; /Florida U.
2012-04-03
We consider SUSY-like missing energy events at hadron colliders and critically examine the common assumption that the missing energy is the result of two identical missing particles. In order to experimentally test this hypothesis, we generalize the subsystem M{sub T2} variable to the case of asymmetric event topologies, where the two SUSY decay chains terminate in different 'children' particles. In this more general approach, the endpoint M{sub T2(max)} of the M{sub T2} distribution now gives the mass {tilde M}p({tilde M}{sub c}{sup (a)}, {tilde M}{sub c}{sup (b)}) of the parent particles as a function of two input children masses {tilde M}{sub c}{sup (a)} and {tilde M}{sub c}{sup (b)}. We propose two methods for an independent determination of the individual children masses M{sub c}{sup (a)} and M{sub c}{sup (b)}. First, in the presence of upstream transverse momentum PUTM the corresponding function {tilde M}p({tilde M}{sub c}{sup (a)}, {tilde M}{sub c}{sup (b)}, P{sub UTM}) is independent of P{sub UTM} at precisely the right values of the children masses. Second, the previously discussed MT2 'kink' is now generalized to a 'ridge' on the 2-dimensional surface {tilde M}p({tilde M}{sub c}{sup (a)}, {tilde M}{sub c}{sup (b)}). As we show in several examples, quite often there is a special point along that ridge which marks the true values of the children masses. Our results allow collider experiments to probe a multi-component dark matter sector directly and without any theoretical prejudice.
The few scales of nuclei and nuclear matter
Delfino, A.; Frederico, T.; Timoteo, V. S.; Tomio, Lauro
2007-01-01
The well-known correlations of low-energy three and four-nucleon observables with a typical three-nucleon scale (e.g., the Tjon line) is extended to light nuclei and nuclear matter. Evidence for the scaling between light nuclei binding energies and the triton one are pointed out. We argue that the saturation energy and density of nuclear matter are correlated to the triton binding energy. The available systematic nuclear matter calculations indicate a possible band structure representing thes...
In-medium effects via nuclear stopping in asymmetric colliding nuclei
Kaur, Mandeep
2016-05-01
The nuclear stopping is studied using isospin-dependent quantum molecular dynamics (IQMD) model in asymmetric colliding nuclei by varying mass asymmetry. The calculations have been done at incident energies varying between 50 and 400 MeV/nucleon for different impact parameters. We investigate the relative role of constant scaled and density-dependent scaled cross-sections. Our study reveals that nuclear stopping depends on the mass asymmetry, incident energy and impact parameter, however, it is independent of the way of scaling the cross-section.
Chiral Fermi liquid description of nuclear matter
International Nuclear Information System (INIS)
We employ Landau's theory of normal Fermi liquids to study the bulk properties of nuclear matter with high-precision two- and three-nucleon interactions derived within the framework of chiral effective field theory. The L=0,1 Landau parameters, characterizing the isotropic and p-wave interaction between two quasiparticles on the Fermi surface, are computed to second order in many-body perturbation theory (MBPT) with chiral and low-momentum two-nucleon forces. Already at this order a number of observables are well described in the theory, including the nuclear isospin asymmetry energy, the quasiparticle effective mass and the spin-isospin response. An adequate description of the nuclear compression modulus (encoded in the Landau parameter F0) requires the inclusion of the leading-order (N2LO) chiral three-nucleon force, which we include to first order in MBPT. The remaining L=0 Landau parameters receive only small corrections from the chiral three-nucleon force, and the L=1 parameters are all reduced, resulting in an effective interaction of apparent short range. We then employ renormalization group techniques to study the scale dependence of the quasiparticle interaction, which allows for an estimation of theoretical uncertainties.
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, Δ'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)
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, αsub(tau) = (N - Z)/A, αsub(N) = (N - N )/A, and αsub(p) = (Z - Z)/A)), contains three symmetry energies: the isospin symmetry energy epsilon sub(σ), the spin symmetry energy epsilon sub(σ), and the spin-isospin symmetry energy epsilon sub(σtau). The relativistic corrections to epsilon sub(tau), epsilon sub(σ) and epsilon sub(σtau) 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)
Strangeness and charm in nuclear matter
Tolos, Laura; Cabrera, Daniel; Garcia-Recio, Carmen; Molina, Raquel; Nieves, Juan; Oset, Eulogio; Ramos, Angels; Romanets, Olena; Salcedo, Lorenzo Luis
2013-09-01
The properties of strange (K, Kbar and K) and open-charm (D, Dbar and D*) mesons in dense matter are studied using a unitary approach in coupled channels for meson-baryon scattering. In the strangeness sector, the interaction with nucleons always comes through vector-meson exchange, which is evaluated by chiral and hidden gauge Lagrangians. For the interaction of charmed mesons with nucleons we extend the SU(3) Weinberg-Tomozawa Lagrangian to incorporate spin-flavor symmetry and implement a suitable flavor symmetry breaking. The in-medium solution for the scattering amplitude accounts for Pauli blocking effects and meson self-energies. On one hand, we obtain the K, Kbar and K spectral functions in the nuclear medium and study their behaviour at finite density, temperature and momentum. We also make an estimate of the transparency ratio of the γA→K+KA‧ reaction, which we propose as a tool to detect in-medium modifications of the K meson. On the other hand, in the charm sector, several resonances with negative parity are generated dynamically by the s-wave interaction between pseudoscalar and vector meson multiplets with 1/2+ and 3/2+ baryons. The properties of these states in matter are analyzed and their influence on the open-charm meson spectral functions is studied. We finally discuss the possible formation of D-mesic nuclei at FAIR energies.
Strangeness and charm in nuclear matter
International Nuclear Information System (INIS)
The properties of strange (K, K¯ and K¯⁎) and open-charm (D, D¯ and D⁎) mesons in dense matter are studied using a unitary approach in coupled channels for meson–baryon scattering. In the strangeness sector, the interaction with nucleons always comes through vector-meson exchange, which is evaluated by chiral and hidden gauge Lagrangians. For the interaction of charmed mesons with nucleons we extend the SU(3) Weinberg–Tomozawa Lagrangian to incorporate spin–flavor symmetry and implement a suitable flavor symmetry breaking. The in-medium solution for the scattering amplitude accounts for Pauli blocking effects and meson self-energies. On one hand, we obtain the K, K¯ and K¯⁎ spectral functions in the nuclear medium and study their behaviour at finite density, temperature and momentum. We also make an estimate of the transparency ratio of the γA→K+K⁎−A′ reaction, which we propose as a tool to detect in-medium modifications of the K¯⁎ meson. On the other hand, in the charm sector, several resonances with negative parity are generated dynamically by the s-wave interaction between pseudoscalar and vector meson multiplets with 1/2+ and 3/2+ baryons. The properties of these states in matter are analyzed and their influence on the open-charm meson spectral functions is studied. We finally discuss the possible formation of D-mesic nuclei at FAIR energies
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)
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)
On the thermal properties of nuclear matter with neutron excess
International Nuclear Information System (INIS)
The schematic model of nuclear matter proposed by Gomes, Walecka and Weisskopf which was generalized to finite temperatures including interacting Fermi particle aspects is extended here to include nuclear matter with neutron excess. The level density parameter as a function of neutron excess is calculated. Also the temperature dependence of the equilibrium Fermi momentum is calculated. (author)
On the thermal properties of polarized nuclear matter
International Nuclear Information System (INIS)
The thermal properties of polarized nuclear matter are calculated using Skyrme III interaction modified by Dabrowski for polarized nuclear matter. The temperature dependence of the volume, isospin, spin and spin isospin pressure and energies are determined. The temperature, isospin, spin and spin isospin dependence of the equilibrium Fermi momentum is also discussed. (author)
Dense Nuclear Matter in a Strong Magnetic Field
International Nuclear Information System (INIS)
We investigate in a relativistic Hartree theory the gross properties of cold symmetric nuclear matter and nuclear matter in beta equilibrium under the influence of strong magnetic fields. If the field strengths are above the critical values for electrons and protons, the respective phase spaces are strongly modified. This results in additional binding of the systems with distinctively softer equations of state compared to the field free cases. For magnetic field ∼1020G and beyond, the nuclear matter in beta equilibrium practically converts into a stable proton-rich matter. copyright 1997 The American Physical Society
Cluster virial expansion for quark and nuclear matter
Blaschke, David
2015-01-01
We employ the $\\Phi-$ derivable approach to many particle systems with strong correlations that can lead to the formation of bound states (clusters) of different size. We define a generic form of $\\Phi-$ functionals that is fully equivalent to a selfconsistent cluster virial expansion up to the second virial coefficient for interactions among the clusters. As examples we consider nuclei in nuclear matter and hadrons in quark matter, with particular attention to the case of the deuterons in nuclear matter and mesons in quark matter. We derive a generalized Beth-Uhlenbeck equation of state, where the quasiparticle virial expansion is extended to include arbitrary clusters. The approach is applicable to nonrelativistic potential models of nuclear matter as well as to relativistic field theoretic models of quark matter. It is particularly suited for a description of cluster formation and dissociation in hot, dense matter.
Nuclear stopping power in warm and hot dense matter
International Nuclear Information System (INIS)
We present a method to estimate the nuclear component of the stopping power of ions propagating in dense matter. Three kinds of effective pair potentials are proposed. Results from the warm dense matter regime and the domain of high energy density physics are presented and discussed for proton and helium. The role of ionic temperature is examined. The nuclear stopping power can play a noticeable role in hot dense matter.
Nucleons, Nuclear Matter and Quark Matter: A unified NJL approach
Lawley, S.; Bentz, W.; Thomas, A.W.
2006-01-01
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.
A fermionic molecular dynamics technique to model nuclear matter
International Nuclear Information System (INIS)
Full text: At sub-nuclear densities of about 1014 g/cm3, nuclear matter arranges itself in a variety of complex shapes. This can be the case in the crust of neutron stars and in core-collapse supernovae. These slab like and rod like structures, designated as nuclear pasta, have been modelled with classical molecular dynamics techniques. We present a technique, based on fermionic molecular dynamics, to model nuclear matter at sub-nuclear densities in a semi classical framework. The dynamical evolution of an antisymmetric ground state is described making the assumption of periodic boundary conditions. Adding the concepts of antisymmetry, spin and probability distributions to classical molecular dynamics, brings the dynamical description of nuclear matter to a quantum mechanical level. Applications of this model vary from investigation of macroscopic observables and the equation of state to the study of fundamental interactions on the microscopic structure of the matter. (author)
Cherenkov and Fano effects at the origin of asymmetric vector mesons in nuclear media
Dremin, I M
2015-01-01
It is argued that the experimentally observed phenomenon of asymmetric vector mesons produced in nuclear media during high energy nucleus-nucleus collisions can be explained as Cherenkov and Fano effects. The mass distributions of lepton pairs created at meson decays decline from the traditional Breit-Wigner shape in the low-mass wing of the resonance. That is explained by the positive real part of the amplitude in this wing for classic Cherenkov treatment and further detalized in quantum mechanics as the interference of direct and continuum states in Fano effect. The corresponding parameters are found from the comparison with rho-meson data and admit reasonable explanation.
Strangeness and charm in nuclear matter
Energy Technology Data Exchange (ETDEWEB)
Tolos, Laura, E-mail: tolos@ice.csic.es [Instituto de Ciencias del Espacio (IEEC/CSIC), Campus Universitat Autònoma de Barcelona, Facultat de Ciències, Torre C5, E-08193 Bellaterra (Barcelona) (Spain); Frankfurt Institute for Advanced Studies, Johann Wolfgang Goethe University, Ruth-Moufang-Str. 1, 60438 Frankfurt am Main (Germany); Cabrera, Daniel [Departamento de Física Teórica II, Universidad Complutense, 28040 Madrid (Spain); Garcia-Recio, Carmen [Departamento de Física Atómica, Molecular y Nuclear, and Instituto Carlos I de Física Teórica y Computacional, Universidad de Granada, E-18071 Granada (Spain); Molina, Raquel [Research Center for Nuclear Physics (RCNP), Mihogaoka 10-1, Ibaraki 567-0047 (Japan); Nieves, Juan; Oset, Eulogio [Instituto de Física Corpuscular (Centro Mixto CSIC-UV), Institutos de Investigación de Paterna, Aptdo. 22085, 46071 Valencia (Spain); Ramos, Angels [Departament d' Estructura i Constituents de la Matèria, Universitat de Barcelona, Diagonal 647, 08028 Barcelona (Spain); Romanets, Olena [Theory Group, KVI, University of Groningen, Zernikelaan 25, 9747 AA Groningen (Netherlands); Salcedo, Lorenzo Luis [Departamento de Física Atómica, Molecular y Nuclear, and Instituto Carlos I de Física Teórica y Computacional, Universidad de Granada, E-18071 Granada (Spain)
2013-09-20
The properties of strange (K, K{sup ¯} and K{sup ¯⁎}) and open-charm (D, D{sup ¯} and D{sup ⁎}) mesons in dense matter are studied using a unitary approach in coupled channels for meson–baryon scattering. In the strangeness sector, the interaction with nucleons always comes through vector-meson exchange, which is evaluated by chiral and hidden gauge Lagrangians. For the interaction of charmed mesons with nucleons we extend the SU(3) Weinberg–Tomozawa Lagrangian to incorporate spin–flavor symmetry and implement a suitable flavor symmetry breaking. The in-medium solution for the scattering amplitude accounts for Pauli blocking effects and meson self-energies. On one hand, we obtain the K, K{sup ¯} and K{sup ¯⁎} spectral functions in the nuclear medium and study their behaviour at finite density, temperature and momentum. We also make an estimate of the transparency ratio of the γA→K{sup +}K{sup ⁎−}A{sup ′} reaction, which we propose as a tool to detect in-medium modifications of the K{sup ¯⁎} meson. On the other hand, in the charm sector, several resonances with negative parity are generated dynamically by the s-wave interaction between pseudoscalar and vector meson multiplets with 1/2{sup +} and 3/2{sup +} baryons. The properties of these states in matter are analyzed and their influence on the open-charm meson spectral functions is studied. We finally discuss the possible formation of D-mesic nuclei at FAIR energies.
Properties of stellar matter in supernova explosions and nuclear multifragmentation
A.S. Botvina; Mishustin, i. N.; Trautmann, W.
2006-01-01
During the collapse of massive stars, and the supernova type-II explosions, stellar matter reaches densities and temperatures which are similar to the ones obtained in intermediate-energy nucleus-nucleus collisions. The nuclear multifragmentation reactions can be used for determination of properties of nuclear matter at subnuclear densities, in the region of the nuclear liquid-gas phase transition. It is demonstrated that the modified properties of hot nuclei (in particular, their symmetry en...
QMD application of sub-saturated nuclear matter
Energy Technology Data Exchange (ETDEWEB)
Maruyama, Toshiki; Maruyama, Tomoyuki; Iwamoto, Akira [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Niita, Koji; Chikamatsu, Kazuhiro
1997-05-01
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.)
Antikaons in infinite nuclear matter and nuclei
International Nuclear Information System (INIS)
In this work we studied the properties of antikaons and hyperons in infinite cold nuclear matter. The in-medium antikaon-nucleon scattering amplitude and self-energy has been calculated within a covariant many-body framework in the first part. Nuclear saturation effects have been taken into account in terms of scalar and vector nucleon mean-fields. In the second part of the work we introduced a non-local method for the description of kaonic atoms. The many-body approach of anti KN scattering can be tested by the application to kaonic atoms. A self-consistent and covariant many-body approach has been used for the determination of the antikaon spectral function and anti KN scattering amplitudes. It considers s-, p- and d-waves and the application of an in-medium projector algebra accounts for proper mixing of partial waves in the medium. The on-shell reduction scheme is also implemented by means of the projector algebra. The Bethe-Salpeter equation has been rewritten, so that the free-space anti KN scattering can be used as the interaction kernel for the in-medium scattering equation. The latter free-space scattering is based on a realistic coupled-channel dynamics and chiral SU(3) Lagrangian. Our many-body approach is generalized for the presence of large scalar and vector nucleon mean-fields. It is supplemented by an improved renormalization scheme, that systematically avoids the occurrence of medium-induced power-divergent structures and kinematical singularities. A modified projector basis has been introduced, that allows for a convenient inclusion of nucleon mean-fields. The description of the results in terms of the 'physical' basis is done with the help of a recoupling scheme based on the projector algebra properties. (orig.)
Kaons in nuclear matter; Kaonen in Kernmaterie
Energy Technology Data Exchange (ETDEWEB)
Kolomeitsev, E.E.
1997-02-01
The subject of the doctoral thesis is examination of the properties of kaons in nuclear matter. A specific method is explained that has been developed for the scientific objectives of the thesis and permits description of the kaon-nucleon interactions and kaon-nucleon scattering in a vacuum. The main challenge involved was to find approaches that would enable application of the derived relations out of the kaon mass shell, connected with the second objective, namely to possibly find methods which are independent of models. The way chosen to achieve this goal relied on application of reduction formulas as well as current algebra relations and the PCAC hypothesis. (orig./CB) [Deutsch] Die Arbeit befasst sich mit der Untersuchung der Eigenschaften von Kao nen in Kernmaterie. Zu diesem Zweck wurde ein Verfahren entwickelt, di e Kaon- Nukleon- Wechselwirkung und Kaon- Nukleon- Streuung im Vakuumzu beschreiben. Die Hauptherausforderung bestand darin, dass die abgel eiteten Relationen ausserhalb der Kaonen- Massenschale anwendbar werde n. Eine Nebenforderung war, dass die vorgeschlagenen Verfahren moeglic hst modell- unabhaengig sind. Um dieses Ziel zu erreichen, wurden Redu ktionsformeln, Stromalgebra- Relationen und die PCAC- Hypothese angewe ndet.
Strangeness and Charm in Nuclear Matter
Tolos, Laura; Garcia-Recio, Carmen; Molina, Raquel; Nieves, Juan; Oset, Eulogio; Ramos, Angels; Romanets, Olena; Salcedo, Lorenzo Luis
2012-01-01
The properties of strange ($K$, $\\bar K$ and $\\bar K^*$) and open-charm ($D$, $\\bar D$ and $D^*$) mesons in dense matter are studied using a unitary approach in coupled channels for meson-baryon scattering. In the strangeness sector, the interaction with nucleons always comes through vector-meson exchange, which is evaluated by chiral and hidden gauge Lagrangians. For the interaction of charmed mesons with nucleons we extend the SU(3) Weinberg-Tomozawa Lagrangian to incorporate spin-flavor symmetry and implement a suitable flavor symmetry breaking. The in-medium solution for the scattering amplitude accounts for Pauli blocking effects and meson self-energies. On one hand, we obtain the $K$, $\\bar K$ and $\\bar K^*$ spectral functions in the nuclear medium and study their behaviour at finite density, temperature and momentum. We also make an estimate of the transparency ratio of the $\\gamma A \\to K^+ K^{*-} A^\\prime$ reaction, which we propose as a tool to detect in-medium modifications of the $\\bar K^*$ meson....
Track theory and nuclear photographic emulsions for Dark Matter searches
International Nuclear Information System (INIS)
This work is devoted to the analysis of possibilities of nuclear emulsions for Dark Matter search, particles of which can produce slow recoil-nuclei. Tracks of such recoil-nuclei in developed nuclear emulsion consist from several emulsion grains. The analysis was carried out with Monte-Carlo calculations made on the basis of the Track Theory and the various factors influencing Dark Matter particles registration efficiency were investigated. Problems, which should be solved for optimal utilization of nuclear emulsions in Dark Matter search, were formulated.Body - Highlights: ► Specific features of Dark Matter Search in nuclear photographic emulsions. ► Track theory for WIMP search in nuclear emulsions. ► Primary efficiency for single WIMP registration. ► Properties of primary WIMP registration efficiency. ► Primary registration efficiency of WIMP flow
Dielectron spectroscopy in cold nuclear matter
International Nuclear Information System (INIS)
The subject of this thesis is the production of light mesons and baryonic resonances in p+Nb collisions at Ekin=3.5 GeV via their decay in e+e- pairs and their kinematic observables. This reaction system in particular allows for the production of vector mesons in approximately cold nuclear matter and the study of expected in-medium effects. The experiment was conducted at the dielectron spectrometer HADES at GSI Helmholtzzentrum fuer Schwerionenforschung GmbH. In total, 64827294 signal pairs with an pair opening angle ?ee>9 and e+/e- momenta 80e(MeV/c)ee(MeV/c2)ee> 550 MeV/c2). Inclusive e+e- production cross sections inside the HADES acceptance were calculated by analyzing the simultaneously measured charged pions and by comparing the obtained ?- yields to an independent data set. For the vector mesons one obtains ??,acc=(65.84.6(stat)18.4(sys)) nb and ??,acc=(7.81.7(stat)2.2 (sys)) nb. A comparison with cross sections in free p+p collisions at Ekin=3.5 GeV results in the nuclear modification factors RpA as well as their scaling ? with the nuclear mass number A and their dependence on the pair lab momenta pee. While absorption is not important for the ? meson (?? ?1), scaling factors ? ?0.7 are established for the quasi free decay (pee>800 MeV/c) of all other hadrons. From an adapted Glauber model calculation a minimal absorption >or similar 35% of all contributing hadrons in nuclei can be deduced. At smaller pair momenta different scaling factors are obtained. The ? meson is absorbed with a higher probability (??=0.62), but for all other sources above the ?0 mass, dominantly ?, ?, and ? with ?=0.82-0.86, production in secondary reactions exceeds the absorption inside the nucleus. Measured e+e- distributions were compared with different transport model calculations. Within the uncertainties the cross section of the ?0 Dalitz decay is reproduced in all models. However differences arise in the high mass region and the distributions of transverse momenta and rapidities. Additionally the GiBUU calculations describe the behaviour of slow and fast e+e- sources due to a momentum dependent in medium decay width. In the experiment no signal of the direct decay ??e+e- was measured. The existing upper level for the branching ratio BR=2.7 x 10-5 has to be reduced by at least a factor of 3. (orig.)
Berec, V.
2016-02-01
We study the coupling and control adaptation of a hybrid electron-nuclear spin system using the laser mediated proton beam in MeV energy regime. The asymmetric control mechanism is based on exact optimization of both: the measure of exchange interaction and anisotropy of the hyperfine interaction induced in the resonance with optimal channeled protons (CP) superfocused field, allowing manipulation over arbitrary localized spatial centers while addressing only the electron spin. Using highly precise and coherent proton channeling regime we have obtained efficient pulse shaping separator technique aimed for spatio-temporal engineering of quantum states, introducing a method for control of nuclear spins, which are coupled via anisotropic hyperfine interactions in isolated electron spin manifold, without radio wave (RW) pulses. The presented method can be efficiently implemented in synchronized spin networks with the purpose to facilitate preservation and efficient transfer of experimentally observed quantum particle states, contributing to the overall background noise reduction.
Energy Technology Data Exchange (ETDEWEB)
Typel, S.; Wolter, H.H. [Sektion Physik, Univ. Muenchen, Garching (Germany)
1998-06-01
Nuclear matter and ground state properties for (proton and neutron) semi-closed shell nuclei are described in relativistic mean field theory with coupling constants which depend on the vector density. The parametrization of the density dependence for {sigma}-, {omega}- and {rho}-mesons is obtained by fitting to properties of nuclear matter and some finite nuclei. The equation of state for symmetric and asymmetric nuclear matter is discussed. Finite nuclei are described in Hartree approximation, including a charge and an improved center-of-mass correction. Pairing is considered in the BCS approximation. Special attention is directed to the predictions for properties at the neutron and proton driplines, e.g. for separation energies, spin-orbit splittings and density distributions. (orig.)
Properties of the ρ-meson in dense nuclear matter
International Nuclear Information System (INIS)
The properties of ρ-mesons in dense nuclear matter are studied in a model which satisfies unitarity and current conservation. The important coupling of the ρ-meson to two pions as well as the strong mixing of pions and delta-nucleon-hole states in nuclear matter are included. The ρ-meson self energy in nuclear matter is evaluated with in-medium pion propagators and the corresponding vertex corrections required by current conservation. We find that the ρ-meson width grows drastically with increasing density while its mass remains almost unchanged. (orig.)
Asset pricing, asymmetric information and rating announcements: does benchmarking on ratings matter?
Spyros Pagratis
2005-01-01
Using an intertemporal model of asset pricing under asymmetric information, we demonstrate how public ratings about the quality of a risky asset could enhance information efficiency, albeit at a cost of higher asset price volatility. The analysis also draws implications for the use of ratings for benchmarking purposes, in particular, ratings-based capital requirements and an investment/subinvestment grade dichotomy depending on the rating of the asset. In this situation, allowing a class of m...
Reflection on penal policy in nuclear matters
International Nuclear Information System (INIS)
This document expresses ethical reflexions as far as nuclear energy development is concerned. The potential diversion of the peaceful use of nuclear energy results in the necessity of a criminal policy which would control the nuclear regulations. For each potential nuclear infringement, systems of laws are established either to prevent damages or to penalize them. (TEC)
Transverse charge densities in the nucleon in nuclear matter
Yakhshiev, Ulugbek
2013-01-01
We investigated the transverse charge densities in the nucleon in nuclear matter within the framework of the in-medium modified Skyrme model. The medium modification of the nucleon electromagnetic form factors are first discussed. The results show that the form factors in nuclear matter fall off faster than those in free space, as the momentum transfer increases. As a result, the charge radii of the nucleon become larger, as the nuclear matter density increases. The transverse charge densities in the nucleon indicate that the size of the nucleon tends to bulge out in nuclear matter. This salient feature of the swelling is more clearly observed in the neutron case. When the proton is transversely polarized, the transverse charge densities exhibit the distortion due to the effects of the magnetization.
K meson-nucleus interactions: strangeness and nuclear matter
International Nuclear Information System (INIS)
A brief review is provided of some straightforward K-nuclear and Λ-hypernuclear systems. A discussion of less straightforward speculations on H-dibaryons and strange quark matter by many authors, is also given. 28 refs., 6 figs
Energy Technology Data Exchange (ETDEWEB)
Ducoin, C
2006-10-15
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)
Many-body theory of nuclear and neutron star matter
Energy Technology Data Exchange (ETDEWEB)
Pandharipande, V.R.; Akmal, A.; Ravenhall, D.G. [Dept. of Physics, Univ. of Illinois at Urbana-Champaign, Urbana, IL (United States)
1998-06-01
We present results obtained for nuclei, nuclear and neutron star matter, and neutron star structure obtained with the recent Argonne v{sub 18} two- nucleon and Urbana IX three-nucleon interactions including relativistic boost corrections. These interactions predict that matter will undergo a transition to a spin layered phase with neutral pion condensation. We also consider the possibility of a transition to quark matter. (orig.)
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)
Dense nuclear matter in a strong magnetic field
Chakrabarty, Somenath; Bandyopadhyay, Debades; Pal, Subrata
1997-01-01
We investigate in a relativistic Hartree theory the gross properties of cold symmetric nuclear matter and nuclear matter in beta equilibrium under the influence of strong magnetic fields. If the field strengths are above the critical values for electrons and protons, the respective phase spaces are strongly modified. This results in additional binding of the systems with distinctively softer equations of state compared to the field free cases. For magnetic field $\\sim 10^{20}$ Gauss and beyon...
Nuclear matter equation of state and three-body forces
Energy Technology Data Exchange (ETDEWEB)
Mansour, H. M. M.; Algamoudi, A. M. A. [Cairo University, Physics Department, Faculty of Science (Egypt)
2012-04-15
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.
Improved nuclear matter calculations from chiral low-momentum interactions
Hebeler, K; Furnstahl, R J; Nogga, A; Schwenk, A
2010-01-01
We present new nuclear matter calculations based on low-momentum interactions derived from chiral effective field theory potentials. The current calculations use an improved treatment of the three-nucleon force contribution that includes a corrected combinatorial factor beyond Hartree-Fock that was omitted in previous nuclear matter calculations. We find realistic saturation properties using parameters fit only to few-body data, but with larger uncertainty estimates from cutoff dependence and the 3NF parametrization than in previous calculations.
Improved nuclear matter calculations from chiral low-momentum interactions
International Nuclear Information System (INIS)
We present nuclear matter calculations based on low-momentum interactions derived from chiral effective field theory potentials. The current calculations use an improved treatment of the three-nucleon force (3NF) contribution that includes a corrected combinatorial factor beyond Hartree-Fock that was omitted in previous nuclear matter calculations. We find realistic saturation properties using parameters fit only to few-body data, but with larger uncertainty estimates from cutoff dependence and the 3NF parametrization than in previous calculations.
Nuclear and neutron matter calculations with different model spaces
International Nuclear Information System (INIS)
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 kM 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 kM. We have carried out model-space nuclear matter and neutron matter calculations with and without PPHH diagrams for various choices of kM and using several modern nucleon-nucleon potentials. Our results exhibit a saturation region where the nuclear and neutron matter energies are quite stable as kM varies. The location of this region may serve to determine an ''optimum'' choice for kM. However, we find that the strength of the tensor force has a significant influence on the variations of binding energy with kM. The implications for nuclear and neutron matter calculations are discussed. (orig.)
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
Higher-order symmetry energy of nuclear matter and the inner edge of neutron star crusts
Seif, W M
2014-01-01
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...
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)
Effective field theory for nuclear matter
Lutz, Matthias
1999-01-01
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.
Energy Technology Data Exchange (ETDEWEB)
Martinik, Tomas, E-mail: tomas.martinik@physics.uu.se [Department of Physics and Astronomy, Uppsala University, Box 516 Sweden, SE-75120 Uppsala (Sweden); Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM, 87545 (United States); Henzl, Vladimir [Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM, 87545 (United States); Grape, Sophie; Svärd, Staffan Jacobsson; Jansson, Peter [Department of Physics and Astronomy, Uppsala University, Box 516 Sweden, SE-75120 Uppsala (Sweden); Swinhoe, Martyn T. [Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM, 87545 (United States); Tobin, Stephen J. [Department of Physics and Astronomy, Uppsala University, Box 516 Sweden, SE-75120 Uppsala (Sweden); Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM, 87545 (United States); Swedish Nuclear Fuel and Waste Management Company, Blekholmstorget 30, Box 250, SE-101 24 Stockholm (Sweden)
2015-07-11
Previous simulation studies of Differential Die‐Away (DDA) instrument’s response to active interrogation of spent nuclear fuel from a pressurized water reactor (PWR) yielded promising results in terms of its capability to accurately measure or estimate basic spent fuel assembly (SFA) characteristics, such as multiplication, initial enrichment (IE) and burn-up (BU) as well as the total plutonium content. These studies were however performed only for a subset of idealized SFAs with a symmetric BU with respect to its longitudinal axis. Therefore, to complement the previous results, additional simulations have been performed of the DDA instrument’s response to interrogation of asymmetrically burned spent nuclear fuel in order to determine whether detailed assay of SFAs from all 4 sides will be necessary in real life applications or whether a cost and time saving single sided assay could be used to achieve results of similar quality as previously reported in case of symmetrically burned SFAs. The results of this study suggest that DDA instrument response depends on the position of the individual neutron detectors and in fact can be split in two modes. The first mode, measured by the back detectors, is not significantly sensitive to the spatial distribution of fissile isotopes and neutron absorbers, but rather reflects the total amount of both contributors as in the cases of symmetrically burned SFAs. In contrary, the second mode, measured by the front detectors, yields certain sensitivity to the orientation of the asymmetrically burned SFA inside the assaying instrument. This study thus provides evidence that the DDA instrument can potentially be utilized as necessary in both ways, i.e. a quick determination of the average SFA characteristics in a single assay, as well as a more detailed characterization involving several DDA observables through assay of the SFA from all of its four sides that can possibly map the burn-up distribution and/or identify diversion or replacement of pins.
International Nuclear Information System (INIS)
Previous simulation studies of Differential Die‐Away (DDA) instrument’s response to active interrogation of spent nuclear fuel from a pressurized water reactor (PWR) yielded promising results in terms of its capability to accurately measure or estimate basic spent fuel assembly (SFA) characteristics, such as multiplication, initial enrichment (IE) and burn-up (BU) as well as the total plutonium content. These studies were however performed only for a subset of idealized SFAs with a symmetric BU with respect to its longitudinal axis. Therefore, to complement the previous results, additional simulations have been performed of the DDA instrument’s response to interrogation of asymmetrically burned spent nuclear fuel in order to determine whether detailed assay of SFAs from all 4 sides will be necessary in real life applications or whether a cost and time saving single sided assay could be used to achieve results of similar quality as previously reported in case of symmetrically burned SFAs. The results of this study suggest that DDA instrument response depends on the position of the individual neutron detectors and in fact can be split in two modes. The first mode, measured by the back detectors, is not significantly sensitive to the spatial distribution of fissile isotopes and neutron absorbers, but rather reflects the total amount of both contributors as in the cases of symmetrically burned SFAs. In contrary, the second mode, measured by the front detectors, yields certain sensitivity to the orientation of the asymmetrically burned SFA inside the assaying instrument. This study thus provides evidence that the DDA instrument can potentially be utilized as necessary in both ways, i.e. a quick determination of the average SFA characteristics in a single assay, as well as a more detailed characterization involving several DDA observables through assay of the SFA from all of its four sides that can possibly map the burn-up distribution and/or identify diversion or replacement of pins
From holography towards real-world nuclear matter
Li, Si-wen; Schmitt, Andreas; Wang, Qun
2015-07-01
Quantum chromodynamics is notoriously difficult to solve at nonzero baryon density, and most models or effective theories of dense quark or nuclear matter are restricted to a particular density regime and/or a particular form of matter. Here we study dense (and mostly cold) matter within the holographic Sakai-Sugimoto model, aiming at a strong-coupling framework in the wide density range between nuclear saturation density and ultrahigh quark matter densities. The model contains only three parameters, and we ask whether it fulfills two basic requirements of real-world cold and dense matter, a first-order onset of nuclear matter and a chiral phase transition at high density to quark matter. Such a model would be extremely useful for astrophysical applications because it would provide a single equation of state for all densities relevant in a compact star. Our calculations are based on two approximations for baryonic matterfirst, an instanton gas and, second, a homogeneous ansatz for the non-Abelian gauge fields on the flavor branes of the model. While the instanton gas shows chiral restoration at high densities but an unrealistic second-order baryon onset, the homogeneous ansatz behaves exactly the other way around. Our study, thus, provides all ingredients that are necessary for a more realistic model and allows for systematic improvements of the applied approximations.
From holography towards real-world nuclear matter
Li, Si-wen; Wang, Qun
2015-01-01
Quantum chromodynamics is notoriously difficult to solve at nonzero baryon density, and most models or effective theories of dense quark or nuclear matter are restricted to a particular density regime and/or a particular form of matter. Here we study dense (and mostly cold) matter within the holographic Sakai-Sugimoto model, aiming at a strong-coupling framework in the wide density range between nuclear saturation density and ultra-high quark matter densities. The model contains only three parameters, and we ask whether it fulfills two basic requirements of real-world cold and dense matter, a first-order onset of nuclear matter and a chiral phase transition at high density to quark matter. Such a model would be extremely useful for astrophysical applications because it would provide a single equation of state for all densities relevant in a compact star. Our calculations are based on two approximations for baryonic matter, firstly an instanton gas and secondly a homogeneous ansatz for the non-abelian gauge fi...
Isospin Violating Dark Matter Search by Nuclear Emulsion Detector
Nagao, Keiko I
2012-01-01
Dark matter signal and its annual modulation of event number are observed by some direct searches in small mass region. However, the regions have been excluded by others. The isospin-violating dark matter is a hopeful candidate to explain the discrepancy. We study the possibility that a future project of dark matter search using nuclear emulsion can reach favored region by the isospin-violating dark matter. Since the detector has the directional sensitivity, it is expected to examine the region including the modulation property.
Updated constraints on velocity and momentum-dependent asymmetric dark matter
Vincent, Aaron C; Serenelli, Aldo
2016-01-01
We present updated constraints on dark matter models with momentum-dependent or velocity-dependent interactions with nuclei, based on direct detection and solar physics. We improve our previous treatment of energy transport in the solar interior by dark matter scattering, leading to significant changes in fits to many observables. Based on solar physics alone, DM with a spin-independent $q^{4}$ coupling provides the best fit to data, and a statistically satisfactory solution to the solar abundance problem. Once direct detection limits are accounted for however, the best solution is spin-dependent $v^2$ scattering with a reference cross-section of 10$^{-35}$ cm$^2$ (at a reference velocity of $v_0=220$ km s$^{-1}$), and a dark matter mass of about 5 GeV.
Formation time scaling and hadronization in cold nuclear matter
Accardi, Alberto
2006-01-01
I propose a scaling analysis of the hadron multiplicity ratio measured in Deep Inelastic Scattering on nuclear targets as a tool to distinguish energy loss and nuclear absorption effects on hadron suppression in cold nuclear matter. The proposed scaling variable is a function of the hadron fractional energy and of the virtual photon energy. Its functional form, which depends on a parameter \\lambda, can be fixed by general theoretical considerations and encompasses both energy loss and absorpt...
On the Origin of the Charge-Asymmetric Matter. II. Localized Dirac Waveforms
Makhlin, Alexander
2016-01-01
This paper continues the author's work \\cite{PartI}, where a new framework of the matter-induced physical geometry was built and an intrinsic nonlinearity of the Dirac equation discovered. Here, the nonlinear Dirac equation is solved and the localized configurations are found analytically. Of the two possible types of the potentially stationary localized configurations of the Dirac field, only one is stable with respect to the action of an external field and it corresponds to a positive charge. A connection with the global charge asymmetry of matter in the Universe and with the recently observed excess of the cosmic positrons is discussed.
Effects of the momentum dependence of potential on the nuclear matter flow
International Nuclear Information System (INIS)
A flow analysis on symmetric and asymmetric reactions from 100 to 400 MeV/n is performed in the framework of the semi-classical Landau-Vlasov approach. Two different trends are presented: at lower energies the flow is governed by the momentum dependence of the nuclear optical potential, whereas at higher energies its density dependence plays a crucial role leading to a rather pronounced sensitivity to the incompressibility modulus. The ingredients of our model are the one-body potential and the nucleon-nucleon collision cross section in the nuclear environment. In the computations the free nucleon nucleon cross section was used. The study of the symmetric system Nb + Nb, for which numerous experimental studies exist, made evident the effect of momentum dependence of the potential. It was found that the experimental data can be reproduced either with a local force having a incompressibility module K∞ = 380 MeV or with a momentum dependent force of K∞ = 228 MeV. To solve this ambiguity, the asymmetric system Ar + Pb at 400 A.MeV was considered. From the dependence of flow parameter on impact parameter one can deduce that only the momentum dependent forces are able to reproduce the experimental data over the entire range of impact parameter while the local forces underestimate systematically the values of the flow parameter. To conclude, a simultaneous study of a symmetric and asymmetrical system shows that only a momentum dependent interaction is able to reproduce the assembly of experimental data related to the nuclear matter flow. From these considerations it results that the incompressibility module is around 230 MeV
Light Asymmetric Dark Matter on the Lattice: SU(2) Technicolor with Two Fundamental Flavors
DEFF Research Database (Denmark)
Lewis, Randy; Pica, Claudio; Sannino, Francesco
2012-01-01
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...
Simulations of cold nuclear matter at sub-saturation densities
Energy Technology Data Exchange (ETDEWEB)
Giménez Molinelli, P.A., E-mail: pagm@df.uba.ar [Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and IFIBA, CONICET, Ciudad Universitaria, Buenos Aires 1428 (Argentina); Nichols, J.I. [Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and IFIBA, CONICET, Ciudad Universitaria, Buenos Aires 1428 (Argentina); López, J.A. [Department of Physics, University of Texas at El Paso, El Paso, TX 79968 (United States); Dorso, C.O. [Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and IFIBA, CONICET, Ciudad Universitaria, Buenos Aires 1428 (Argentina)
2014-03-01
Ideal nuclear matter is expected to undergo a first order phase transition at the thermodynamic limit. At such phase transitions the size of density fluctuations (bubbles or droplets) scale with the size of the system. This means that simulations of nuclear matter at sub-saturation densities will inexorably suffer from what is vaguely referred to as “finite size effects”. It is usually thought that these finite size effects can be diminished by imposing periodic boundary conditions and making the system large enough, but as we show in this work, that is actually not the case at sub-saturation densities. In this paper we analyze the equilibrium configurations of molecular dynamics simulations of a classical model for symmetric ideal (uncharged) nuclear matter at sub-saturation densities and low temperatures, where phase coexistence is expected at the thermodynamic limit. We show that the most stable configurations in this density range are almost completely determined by artificial aspects of the simulations (i.e. boundary conditions) and can be predicted analytically by surface minimization. This result is very general and is shown to hold true for several well known semi-classical models of nuclear interaction and even for a simple Lennard-Jones potential. Also, in the limit of very large systems, when “small size” effects can be neglected, those equilibrium configurations seem to be restricted to a few structures reminiscent to the “Pasta Phases” expected in Neutron Star matter, but arising from a completely different origin: In Neutron Star matter, the non-homogeneous structures arise from a competition between nuclear and Coulomb interactions while for ideal nuclear matter they emerge from finite (yet not “small”) size effects. The role of periodic boundary conditions and finite size effects in Neutron Star matter simulations are reexamined.
Simulations of cold nuclear matter at sub-saturation densities
International Nuclear Information System (INIS)
Ideal nuclear matter is expected to undergo a first order phase transition at the thermodynamic limit. At such phase transitions the size of density fluctuations (bubbles or droplets) scale with the size of the system. This means that simulations of nuclear matter at sub-saturation densities will inexorably suffer from what is vaguely referred to as “finite size effects”. It is usually thought that these finite size effects can be diminished by imposing periodic boundary conditions and making the system large enough, but as we show in this work, that is actually not the case at sub-saturation densities. In this paper we analyze the equilibrium configurations of molecular dynamics simulations of a classical model for symmetric ideal (uncharged) nuclear matter at sub-saturation densities and low temperatures, where phase coexistence is expected at the thermodynamic limit. We show that the most stable configurations in this density range are almost completely determined by artificial aspects of the simulations (i.e. boundary conditions) and can be predicted analytically by surface minimization. This result is very general and is shown to hold true for several well known semi-classical models of nuclear interaction and even for a simple Lennard-Jones potential. Also, in the limit of very large systems, when “small size” effects can be neglected, those equilibrium configurations seem to be restricted to a few structures reminiscent to the “Pasta Phases” expected in Neutron Star matter, but arising from a completely different origin: In Neutron Star matter, the non-homogeneous structures arise from a competition between nuclear and Coulomb interactions while for ideal nuclear matter they emerge from finite (yet not “small”) size effects. The role of periodic boundary conditions and finite size effects in Neutron Star matter simulations are reexamined
Equation of state for β-stable hot nuclear matter
International Nuclear Information System (INIS)
We provide an equation of state for hot nuclear matter in β equilibrium by applying a momentum-dependent effective interaction. We focus on the study of the equation of state of high-density and high-temperature nuclear matter, containing leptons (electrons and muons) under the chemical equilibrium condition in which neutrinos have left the system. The conditions of charge neutrality and equilibrium under the β-decay process lead first to the evaluation of proton and lepton fractions and then to the evaluation of internal energy, free energy, and pressure, and in total to the equation of state of hot nuclear matter. Thermal effects on the properties and equation of state of nuclear matter are assessed and analyzed in the framework of the proposed effective interaction model. Special attention is given to the study of the contribution of the components of β-stable nuclear matter to the entropy per particle, a quantity of great interest in the study of structure and collapse of supernova.
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.)
Nuclear-like states of quark matter
International Nuclear Information System (INIS)
In a world with only one flavor of light quark, QCD suggests that the low energy states of quark matter are similar to nuclei, but are not well represented as collections of baryons. Except for the existence of open nucleon channels, the same would be true for the actual, two-light-flavor world. 3 refs
Extended Skyrme interactions for nuclear matter, finite nuclei and neutron stars
Zhang, Zhen
2015-01-01
Recent progress in theory, experiment and observation challenges the mean field models using the conventional Skyrme interaction, suggesting that the extension of the conventional Skyrme interaction is necessary. In this work, we construct three Skyrme interaction parameter sets, namely, eMSL07, eMSL08 and eMSL09, based on an extended Skyrme interaction which includes additional momentum and density dependent two-body forces to effectively simulate the momentum dependence of the three-body force. The three new interactions can well reproduce both the ground-state properties and isoscalar giant monopole resonance energy of finite nuclei, nicely conform to the current knowledge on the equation of state of asymmetric nuclear matter around and below saturation density $\\rho_0$, eliminate the notorious unphysical instabilities of symmetric nuclear matter and pure neutron matter at densities up to about $7.5\\rho_0$, and simultaneously support heavier neutron stars with mass larger than two times solar mass. The new...
Nowakowski, Daniel; Carignano, Stefano
2016-01-01
We investigate the effects of isospin asymmetry on the competition between color-superconductivity and inhomogeneous chiral symmetry breaking in dense two-flavor quark matter using an extended Nambu--Jona-Lasinio model. We confirm the appearance of a coexistence window where chiral symmetry is inhomogeneously broken and a nonzero spatially homogeneous diquark gap is present, consistently with previous works, and show that such a phase survives at nonzero isospin chemical potentials. We also d...
Dark Matter Particle Spectroscopy at the LHC: Generalizing MT2 to Asymmetric Event Topologies
Konar, Partha; Matchev, Konstantin T; Park, Myeonghun
2009-01-01
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 MT2max of the MT2 distribution now gives the mass Mp(Mc(a),Mc(b)) of the parent particle as a function of two input children masses Mc(a) and Mc(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 P(UTM) the corresponding function Mp(Mc(a),Mc(b),P(UTM)) is independent of P(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 Mp(Mc(a),Mc(b)). As we show in sev...
Nuclear power - a matter of confidence
International Nuclear Information System (INIS)
It is the Central Electricity Generating Board's view that nuclear power is a safe technology and, on reasonable hypotheses, a sound economic investment of national resources. This booklet, based on a talk to members of Parliament in October 1981, sets out the reasons for this. The proposal to build a pressurized water reactor at Sizewell (Sizewell-B) is set in the historical and economic context of the overall energy policy. It acknowledges that public acceptability and the strategy for developing nuclear power in this country are the main problems facing the CEGB's nuclear policy. The Sizewell-B public enquiry is seen as a chance of gaining public confidence in the decision-making process associated with nuclear power. (U.K.)
Holographic cold nuclear matter as dilute instanton gas
Ghoroku, Kazuo; Tachibana, Motoi; Taminato, Tomoki; Toyoda, Fumihiko
2012-01-01
We study cold nuclear matter based on the holographic gauge theory, where baryons are introduced as the instantons in the probe D8/$\\bar{\\rm D8}$ branes according to the Sakai-Sugimoto model. Within a dilute gas approximation of instantons, we seek for the stable states via the variational method and fix the instanton size. We find the first order phase transition from the vacuum to the nuclear matter phase as we increase the chemical potential. At the critical chemical potential, we could see a jump of the baryon density from zero to a finite definite value. While the size of the baryon in the nuclear matter is rather small compared to the nucleus near the transition point, where the charge density is also small, it increases with the baryon density. Those behaviors obtained here are discussed by relating to the force between baryons.
Valid QCD sum rules for vector mesons in nuclear matter
International Nuclear Information System (INIS)
QCD sum rules for vector mesons (ρ, ω, φ) in nuclear matter are re-examined with an emphasis on the reliability of various sum rules. Monitoring the continuum contribution and the convergence of the operator product expansion plays crucial role in determining the validity of a sum rule. The uncertainties arising from less than precise knowledge of the condensate values and other input parameters are analyzed via a Monte Carlo error analysis. Our analysis leaves no doubt that vector-meson masses decrease with increasing density. This resolves the current debate over the behavior of the vector-meson masses and the sum rules to be used in extracting vector meson properties in nuclear matter. We find a ratio of ρ-meson masses of mρ*/mρ = 0.78 ± 0.08 at nuclear matter saturation density. (author). 37 refs., 6 figs
Axion electrodynamics and nonrelativistic photons in nuclear and quark matter
Yamamoto, Naoki
2016-04-01
We argue that the effective theory for electromagnetic fields in spatially varying meson condensations in dense nuclear and quark matter is given by the axion electrodynamics. We show that one of the helicity states of photons there has the nonrelativistic gapless dispersion relation ω ˜k2 at small momentum, while the other is gapped. This "nonrelativistic photon" may also be realized at the interface between topological and trivial insulators in condensed matter systems.
The Strangeness and Charm of Dense Nuclear Matter
International Nuclear Information System (INIS)
The creation of strangeness and charm in nucleus-nucleus collisions at threshold beam energies is discussed as a probe for compressed baryonic matter. Experimental data on strangeness production at SIS energies indicate that the properties of kaons and antikaons are modified in dense nuclear matter. An experiment is proposed at the future GSI facility to explore the QCD phase diagram in the region of highest baryon densities. An important observable will be charm production close to threshold. (author)
On the influence of the nuclear medium on the new nuclear matter states
International Nuclear Information System (INIS)
In many nucleus-nucleus collisions at high energies an increase of the particle production below the free nucleon-nucleon threshold has been observed. This increase can be related to the effects of the nuclear medium on the properties of the elementary particles, as well as on the new states of the nuclear matter, as resonance matter, for example. The present work takes into account the previous predictions on the rest mass particle modifications and resonance matter formation to discuss the influences of the nuclear medium on this new nuclear matter state. Experimental results on neutron-proton collisions at momenta between 1.25 GeV/c and 5.1 GeV/c, as well as on nucleus-nucleus collisions at energies between 1 A GeV and 15 A GeV are considered. Nuclear density and temperature determinations mainly at the pion emission, and the effective mass are used to establish the rest mass modification and the resonance weights in the considered collisions. A significant increase of the resonance matter formation is observed in nucleus-nucleus collisions, as compared with nucleon-nucleon collisions, at the same energy. The behaviour of the resonance matter formation in nucleus-nucleus collisions is also discussed. A like-saturation behaviour with energy increase can be considered. The major conclusion is that the nuclear medium has an important influence on the new states of nuclear matter. (authors)
Condensates and correlations in nuclear matter
Directory of Open Access Journals (Sweden)
Röpke G.
2010-10-01
Full Text Available Nuclei in dense matter are inﬂuenced by the medium. Solving an A-particle Schroedinger equation including the eﬀects of self-energy and Pauli blocking, a quasiparticle description is introduced. Deriving thermodynamic properties, this approach contains the NSE at low densities as well as mean-ﬁeld approaches at high densities. Consequences for the symmetry energy, the phase transition, the determination of thermodynamic parameters from cluster yields and astrophysical applications are discussed.
Nowakowski, Daniel
2016-01-01
We investigate the effects of isospin asymmetry on the competition between color-superconductivity and inhomogeneous chiral symmetry breaking in dense two-flavor quark matter using an extended Nambu--Jona-Lasinio model. We confirm the appearance of a coexistence window where chiral symmetry is inhomogeneously broken and a nonzero spatially homogeneous diquark gap is present, consistently with previous works, and show that such a phase survives at nonzero isospin chemical potentials. We also discuss how the model phase structure becomes modified as large isospin asymmetries are considered.
Gamma-ray triangles: a possible signature of asymmetric dark matter in indirect searches
Ibarra, Alejandro; Lopez-Gehler, Sergio; Molinaro, Emiliano; Pato, Miguel
2016-01-01
We introduce a new type of gamma-ray spectral feature, which we denominate gamma-ray triangle. This spectral feature arises in scenarios where dark matter self-annihilates via a chiral interaction into two Dirac fermions, which subsequently decay in flight into another fermion and a photon. The resulting photon spectrum resembles a sharp triangle and can be readily searched for in the gamma-ray sky. Using data from the Fermi-LAT and H.E.S.S. instruments, we find no evidence for such spectral ...
Consistent treatment of isobar degrees of freedom in nuclear matter
International Nuclear Information System (INIS)
It is argued that the present situation in nuclear matter requires an explicit description of the 2π exchange contribution to the NN interaction providing the intermediate-range attraction. Especially, a realistic treatment of isobar degrees of freedom is strongly suggested. A suitable scheme is described, which starts from a field-theoretic Hamiltonian and uses old-fashioned perturbation theory consistently in the two- and the many-body problem. Numerical results (for NN scattering data and nuclear matter binding) emerging from such an approach are briefly outlined. (Auth.)
The role of tensor force in nuclear matter saturation
Banerjee, M K; Banerjee, Manoj K.; Tjon, John A.
1998-01-01
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.
The role of tensor force in nuclear matter saturation
Banerjee, Manoj K.; Tjon, John A.
1997-01-01
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 d...
Energy-range relations for hadrons in nuclear matter
Strugalski, Z.
1985-01-01
Range-energy relations for hadrons in nuclear matter exist similarly to the range-energy relations for charged particles in materials. When hadrons of GeV kinetic energies collide with atomic nuclei massive enough, events occur in which incident hadron is stopped completely inside the target nucleus without causing particle production - without pion production in particular. The stoppings are always accompanied by intensive emission of nucleons with kinetic energy from about 20 up to about 400 MeV. It was shown experimentally that the mean number of the emitted nucleons is a measure of the mean path in nuclear matter in nucleons on which the incident hadrons are stopped.
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 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
The modification of the scalar field in dense nuclear matter
International Nuclear Information System (INIS)
We show the possible evolution of the nuclear deep inelastic structure function with nuclear density ρ. The nucleon deep inelastic structure function represents distribution of quarks as a function of Bjorken variable x, which measures the longitudinal fraction of the momentum carried by them during deep inelastic scattering (DIS) of electrons on nuclear targets. The quark localization is proportional to 1/x and this relation introduces the dependence of the nucleon structure function on the nuclear medium. Starting with small density and negative pressure in nuclear matter (NM), we have relatively large inter-nucleon distances and increasing role of nuclear interaction mediated by virtual mesons. When the density approaches the saturation point, ρ = ρ0, we have no longer separate mesons and nucleons but eventually modified nucleon structure function (SF) in the medium. The ratio of the nuclear to the nucleon SF measured at the saturation point is well known as the "EMC effect". For larger density, ρ > ρ0, when the localization of quarks is smaller than 0.3 fm, the nucleons overlap. We argue that nucleon mass should start to decrease in order to satisfy the momentum sum rule (MSR) of DIS. These modifications of the nucleon structure function are calculated in the frame of the nuclear relativistic mean field (RMF) convolution model. The correction to the Fermi energy from a term proportional to the pressure is very important and its inclusion modifies the equation of state (EoS) for the nuclear matter. (author)
Experimental signals of the first phase transition of nuclear matter
International Nuclear Information System (INIS)
Vaporized and multi-fragmenting sources produced in heavy ion collisions at intermediate energies are good candidates to investigate the phase diagram of nuclear matter. The properties of highly excited nuclear sources which undergo a simultaneous disassembly into particles are found to sign the presence of a gas phase. For heavy nuclear sources produced in the Fermi energy domain, which undergo a simultaneous disassembly into particles and fragments, a fossil signal (fragment size correlations) reveals the origin of multifragmentation: spinodal instabilities which develop in the unstable coexistence region of the phase diagram of nuclear matter. Studies of fluctuations give a direct signature of a first order phase transition through measurements of a negative microcanonical heat capacity. (author)
Supernovae and high density nuclear matter
Energy Technology Data Exchange (ETDEWEB)
Kahana, S.
1986-01-01
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.
Exponential enhancement of nuclear reactions in condensed matter environment
Kuchiev, M . Yu.; Altshuler, B.L.; Flambaum., V. V.
2003-01-01
A mechanism that uses the environment to enhance the probability of the nuclear reaction when a beam of accelerated nuclei collides with a target nucleus implanted in condensed matter is suggested. The effect considered is exponentially large for low collision energies. For t + p collision the mechanism becomes effective when the energy of the projectile tritium is below $\\sim$ 1 Kev per nucleon. The gain in probability of the nuclear reaction is due to a redistribution of energy and momentum...
Tensor Coupling and Vector Mesons in Dense Nuclear Matter
Mazumder, Abhee Kanti Dutt-; Dutta-Roy, Binayak; Kundu, Anirban; De, Triptesh
1995-01-01
The effects of magnetic interaction between vector mesons and nucleons on the propagation (mass and width) of the $\\rho$-meson in particular moving through very dense nuclear matter is studied and the modifications, qualitative and quantitative, due to the relevant collective modes (zero-sound and plasma frequencies) of the medium discussed. It is shown that the $\\rho$-mesons produced in high-energy nuclear collisions will be longitudinally polarized in the region of sufficiently dense nuclea...
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 RBPJκ (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 RBPJκ 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 RBPJκ.
The Modification of the Scalar Field in dense Nuclear Matter
Directory of Open Access Journals (Sweden)
Rożynek J.
2011-04-01
Full Text Available We show the possible evolution of the nuclear deep inelastic structure function with nuclear density ρ. 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, ρ = ρ0, 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, ρ > ρ0, 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.
Yurt Lambrecht, Fatma; Ocakoglu, Kasim; Er, Ozge; Ince, Mine; Gunduz, Cumhur; Kayabası, Cagla
2016-05-15
Photodynamic therapy (PDT) is based on exposing a light-sensitive material that has been localized in target tissues with visible light. In the current study, symmetric Zn(II) octaoctadodecylphthalocyanine (1) and the asymmetrically substituted hydroxyhexyloxy derivative (2) were examined as a multifunctional agent for tumour nuclear imaging and for PDT potential. Zn(II)Pc 1 and Zn(II)Pc 2 were radiolabelled with (131) I using an iodogen method with high efficiency (93.5 ± 3.5% and 93.0 ± 2.8%, respectively) under the optimum conditions. Biodistribution study results showed that radiolabelled Zn(II)Pc 1 had a high uptake in the large intestine and unchanging uptake in the ovary. However, radiolabelled Zn(II)Pc 2 uptake was statically significant in the large intestine, pancreas, ovary and lung. For the PDT studies, EMT6/P (mouse mammary cell line) and HeLa (cervical adenocarcinoma cell line) with Zn(II)Pc 1 and Zn(II)Pc 2 were exposed to red light (650 nm) at 10-30 J/cm(2) . Zn(II)Pc 1 and Zn(II)Pc 2 had a good PDT efficacy in the EMT6/P cell line. In conclusion, radiolabelled Zn(II)Pc 1 might be a promising imaging agent for pancreas, ovary and colon tumours. However, the radiolabelled Zn(II)Pc 2 might be a promising nuclear imaging and PDT agent for colon, lung, pancreas and ovary tumours. PMID:27059543
Condensed matter nuclear reactions with metal particles in gases
International Nuclear Information System (INIS)
Various metals have been used by a number of researchers to study the condensed matter nuclear reactions occurring within the metal lattice when exposed to gases containing hydrogen, its deuterium isotope and various mixes. This article will give a brief overview of such studies. (author)
The coexistence curve of finite charged nuclear matter
Energy Technology Data Exchange (ETDEWEB)
Elliott, J.B.; Moretto, L.G.; Phair, L.; Wozniak, G.J.; Beaulieu, L.; Breuer, H.; Korteling, R.G.; Kwiatkowski, K.; Lefort, T.; Pienkowski, L.; Ruangma, A.; Viola, V.E.; Yennello, S.J.; Albergo, S.; Bieser, F.; Brady, F.P.; Caccia, Z.; Cebra, D.A.; Chacon, A.D.; Chance, J.L.; Choi, Y.; Costa, S.; Gilkes, M.L.; Hauger, J.A.; Hirsch, A.S.; Hjort, E.L.; Insolia, A.; Justice, M.; Keane, D.; Kintner, J.C.; Lindenstruth, V.; Lisa, M.A.; Matis, H.S.; McMahan, M.; McParland, C.; Muller, W.F.J.; Olson, D.L.; Partlan, M.D.; Porile, N.T.; Potenza, R.; Rai, G.; Rasmussen, J.; Ritter, H.G.; Romanski, J.; Romero, J.L.; Russo, G.V.; Sann, H.; Scharenberg, R.P.; Scott, A.; Shao, Y.; Srivastava, B.K.; Symons, T.J.M.; Tincknell, M.; Tuve, C.; Wang , S.; Warren, P.; Wieman, H.H.; Wienold, T.; Wolf, K.
2001-01-01
The multifragmentation data of the ISiS Collaboration and the EOS Collaboration are examined. Fisher's droplet formalism, modified to account for Coulomb energy, is used to determine the critical exponents {tau} and {sigma}, the surface energy coefficient c{sub 0}, the pressure-temperature-density coexistence curve of finite nuclear matter and the location of the critical point.
Role of Hyperon Negative Energy Sea in Nuclear Matter
Ellis, P.J.; Parendo, S. B.; M Prakash
1995-01-01
We have examined the contribution of the filled negative energy sea of hyperons to the energy/particle in nuclear matter at the one and two loop levels. While this has the potential to be significant, we find a strong cancellation between the one and two loop contributions for our chosen parameters so that hyperon effects can be justifiably neglected.
Cluster formation and the nuclear matter equation of state
International Nuclear Information System (INIS)
Bound state formation is considered in nuclear matter within the frame of many-particle theory. Medium effects such as self-energy and Pauli blocking will modify the single-particle properties as well as the cluster properties. Consequences for the composition, the formation of quantum condensates and the symmetry energy are given. (author)
The coexistence curve of finite charged nuclear matter
International Nuclear Information System (INIS)
The multifragmentation data of the ISiS Collaboration and the EOS Collaboration are examined. Fisher's droplet formalism, modified to account for Coulomb energy, is used to determine the critical exponents ? and ?, the surface energy coefficient c0, the pressure-temperature-density coexistence curve of finite nuclear matter and the location of the critical point
Nuclear matter from chiral low-momentum interactions
Bogner, S K; Nogga, A; Schwenk, A
2009-01-01
Nuclear matter calculations based on low-momentum interactions derived from chiral nucleon-nucleon and three-nucleon effective field theory interactions and fit only to few-body data predict realistic saturation properties with controlled uncertainties. This is promising for a unified description of nuclei and to develop a universal density functional based on low-momentum interactions.
Zhou, Zhengzhen; Guo, Laodong
2015-06-19
Colloidal retention characteristics, recovery and size distribution of model macromolecules and natural dissolved organic matter (DOM) were systematically examined using an asymmetrical flow field-flow fractionation (AFlFFF) system under various membrane size cutoffs and carrier solutions. Polystyrene sulfonate (PSS) standards with known molecular weights (MW) were used to determine their permeation and recovery rates by membranes with different nominal MW cutoffs (NMWCO) within the AFlFFF system. Based on a ≥90% recovery rate for PSS standards by the AFlFFF system, the actual NMWCOs were determined to be 1.9 kDa for the 0.3 kDa membrane, 2.7 kDa for the 1 kDa membrane, and 33 kDa for the 10 kDa membrane, respectively. After membrane calibration, natural DOM samples were analyzed with the AFlFFF system to determine their colloidal size distribution and the influence from membrane NMWCOs and carrier solutions. Size partitioning of DOM samples showed a predominant colloidal size fraction in the flow field-flow fractionation technique. In addition, the coupling of AFlFFF with fluorescence EEMs could provide new insights into DOM heterogeneity in different colloidal size fractions. PMID:25958093
From cold to hot nuclear matter
Bratkovskaya, E. L.; Cassing, W.; Konchakovski, V. P.; Toneev, V. D.
2015-11-01
The dynamics of partons and hadrons in relativistic nucleus-nucleus collisions is analyzed within the Parton-Hadron-String Dynamics (PHSD) transport approach which is based on a dynamical quasiparticle model for the partonic phase (DQPM) including a dynamical hadronization scheme with covariant transition rates. The PHSD approach is applied to nucleus-nucleus collisions from FAIR/NICA to LHC energies. The traces of partonic interactions are found in particular in the directed and elliptic flow of hadrons and in their transverse mass spectra. Whereas at RHIC and LHC energies the dynamics is dominated by partonic degrees-of-freedom in the hot QGP, we find at FAIR/NICA energies a moderately hot but dense matter where chiral symmetry restoration and hadronic potentials appear to play a major role.
Pairing in bulk nuclear matter beyond BCS
Ding, D; Dickhoff, W H; Dussan, H; Rios, A; Polls, A
2014-01-01
The influence of short-range correlations on the spectral distribution of neutrons is incorporated in the solution of the gap equation for the ${}^3P_2-{}^3F_2$ coupled channel in pure neutron matter. This effect is studied for different realistic interactions including one based on chiral perturbation theory. The gap in this channel vanishes at all relevant densities due to the treatment of these correlations. We also consider the effect of long-range correlations by including polarization terms in addition to the bare interaction which allow the neutrons to exchange density and spin fluctuations governed by the strength of Landau parameters allowed to have reasonable values consistent with the available literature. Preliminary results indicate that reasonable values of these parameters do not generate a gap in the ${}^3P_2-{}^3F_2$ coupled channel either for all three realistic interactions although the pairing interaction becomes slightly more attractive.
Energy Technology Data Exchange (ETDEWEB)
Margueron, J
2001-07-01
We study the elementary interactions between neutrinos and dense matter in a proto-neutron star. Equations of state obtained with different nuclear effective interactions (Skyrme, Gogny, Relativistic Lagrangians) are first discussed. Then, we characterize their stability in spin and isospin. We derive magnetic susceptibilities for all isospin asymmetry values as a function of Landau parameters G{sup {pi}}{sup {pi}}{sup '}{sub 0} (where {pi}, {pi}' = proton or neutron). From this work, we select a parametrization for each of the 3 effective forces: Sly230b,D1P,NL3. We calculate the pure neutron matter and asymmetric nuclear matter response functions with and without charge exchange, describing nuclear correlations in both approaches: non-relativistic (Hartree-Fock with Skyrme forces, then complete RPA) and relativistic (in the Hartree approximation). At the end, we calculate neutrino mean free paths neutral current and charged current reactions. Comparisons between relativistic and non-relativistic approaches allow us to identify relativistic effects in nuclear matter at densities as low as twice the saturation density. RPA correlations make the medium more transparent to neutrinos compared to free Fermi gas. The importance of the effective mass in mean free path calculations is also shown. (author)
Relativistic Mean-Field Models and Nuclear Matter Constraints
Dutra, M; Carlson, B V; Delfino, A; Menezes, D P; Avancini, S S; Stone, J R; Providncia, C; Typel, S
2013-01-01
This work presents a preliminary study of 147 relativistic mean-field (RMF) hadronic models used in the literature, regarding their behavior in the nuclear matter regime. We analyze here different kinds of such models, namely: (i) linear models, (ii) nonlinear \\sigma^3+\\sigma^4 models, (iii) \\sigma^3+\\sigma^4+\\omega^4 models, (iv) models containing mixing terms in the fields \\sigma and \\omega, (v) density dependent models, and (vi) point-coupling ones. In the finite range models, the attractive (repulsive) interaction is described in the Lagrangian density by the \\sigma (\\omega) field. The isospin dependence of the interaction is modeled by the \\rho meson field. We submit these sets of RMF models to eleven macroscopic (experimental and empirical) constraints, used in a recent study in which 240 Skyrme parametrizations were analyzed. Such constraints cover a wide range of properties related to symmetric nuclear matter (SNM), pure neutron matter (PNM), and both SNM and PNM.
Matter in extremis: Ultrarelativistic nuclear collisions at RHIC
Energy Technology Data Exchange (ETDEWEB)
Jacobs, Peter; Wang, Xin-Nian
2004-08-20
We review the physics of nuclear matter at high energy density and the experimental search for the Quark-Gluon Plasma at the Relativistic Heavy Ion Collider (RHIC). The data obtained in the first three years of the RHIC physics program provide several lines of evidence that a novel state of matter has been created in the most violent, head-on collisions of Au nuclei at {radical}s = 200 GeV. Jet quenching and global measurements show that the initial energy density of the strongly interacting medium generated in the collision is about two orders of magnitude larger than that of cold nuclear matter, well above the critical density for the deconfinement phase transition predicted by lattice QCD. The observed collective flow patterns imply that the system thermalizes early in its evolution, with the dynamics of its expansion consistent with ideal hydrodynamic flow based on a Quark-Gluon Plasma equation of state.
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
Stieltjes, Frederik Bernd Laun Wolfhard Semmler Bram
2010-01-01
Temporally asymmetric gradient profiles in nuclear magnetic resonance diffusion experiments are investigated using modified Stejskal-Tanner gradients. Three novel findings are presented. 1. The phase of the diffusion-weighted signal contains information about the confining geometry. This information can be extracted from the 'diffusion-weighted phase'. 2. In the motional narrowing regime, it is possible to exactly determine the confining boundary in closed domains. 3. Diffusion-weighting gradients can act like imaging gradients.
International Nuclear Information System (INIS)
Here we perform a systematic study to extract the information for colliding nuclear matter via symmetry energy and nucleon-nucleon cross section in the fragmentation of some asymmetric colliding nuclei (O16+Br80, 84, 92) in the energy range between 50-200 MeV/nucleon. The simulations are carried out using isospin-dependent quantum-molecular dynamics (IQMD) computational approach for central collisions. Our study reveals that fragmentation pattern of neutron-rich colliding nuclei is sensitive to symmetry energy at lower incident energies, whereas isospin dependence of nucleon-nucleon cross section becomes dominant for reactions at higher incident energies
Meson production in dense nuclear matter
International Nuclear Information System (INIS)
Pion and Kaon production has been studied in symmetric nucleus-nucleus collisions at beam energies between 0.8 and 1.8 AGeV. The anisotropic azimuthal emission of pions in semi-central collisions can be explained by the emission of high-energy pions in early stage of the collision and a late ''freeze-out'' of low energy pions. In nucleus-nucleus collisions at 1 AGeV, the K+ multiplicity increases more than linearly both with A (in A + A collisions) and with Apart (i.e. the number of participating nucleons in Au + Au collisions). This nonlinear behaviour is due to collective effects such as multiple hadron-hadron encounters. According to transport calculations, the large K+ cross section observed for Au + Au collisions at 1 AGeV is a consequence of a soft nuclear equation of state. The large K-/K+ ratio measured in Ni + Ni collisions at equivalent beam energies (compared to p+p collisions) is a signature for an enhanced in-medium K- production. In order to reproduce the data, transport models have to consider a reduction of the K- mass in the dense nuclear medium. (author)
Nonlinear mean field theory for nuclear matter and surface properties
International Nuclear Information System (INIS)
Nuclear matter properties are studied in a nonlinear relativistic mean field theory. We determine the parameters of the model from bulk properties of symmetric nuclear matter and a reasonable value of the effective mass. In this work, we stress the nonrelativistic limit of the theory which is essentially equivalent to a Skyrme hamiltonian, and we show that most of the results can be obtained, to a good approximation, analytically. The strength of the required parameters is determined from the binding energy and density of nuclear matter and the effective nucleon mass. For realistic values of the parameters, the nonrelativistic approximation turns out to be quite satisfactory. Using reasonable values of the parameters, we can account for other key properties of nuclei, such as the spin-orbit coupling, surface energy, and diffuseness of the nuclear surface. Also the energy dependence of the nucleon-nucleus optical model is accounted for reasonably well except near the Fermi surface. It is found, in agreement with empirical results, that the Landau parameter F0 is quite small in normal nuclear matter. Both density dependence and momentum dependence of the NN interaction, but especially the former, are important for nuclear saturation. The required scalar and vector coupling constants agree fairly well with those obtained from analyses of NN scattering phase shifts with one-boson-exchange models. The mean field theory provides a semiquantitative justification for the weak Skyrme interaction in odd states. The strength of the required nonlinear term is roughly consistent with that derived using a new version of the chiral mean field theory in which the vector mass as well as the nucleon mass is generated by the sigma-field. (orig.)
$D_S$ Mesons in Asymmetric Hot and Dense Hadronic Matter
Pathak, Divakar
2014-01-01
The in-medium properties of $D_S$ mesons are investigated within the framework of a chiral effective model. These are observed to experience net attractive interactions in a dense hadronic medium, hence reducing the masses of the $D_S^+$ and $D_S^-$ mesons from the vacuum values. While this conclusion holds in both nuclear and hyperonic media, the magnitude of the mass drop is observed to intensify with the inclusion of strangeness in the medium. Additionally, in hyperonic medium, the mass degeneracy of the $D_S$ mesons is observed to be broken, due to opposite signs of the Weinberg-Tomozawa interaction term in the Lagrangian density. Along with the magnitude of the mass drops, the mass splitting between $D_S^+$ and $D_S^-$ mesons is also observed to grow with an increase in baryonic density and strangeness content of the medium. However, all medium effects analyzed are found to be weakly dependent on isospin asymmetry and temperature. We discuss the possible implications emanating from this analysis, which a...
Enhancement of nuclear reactions in matter
International Nuclear Information System (INIS)
Full text: We analyze enhancement of the nuclear fusion initiated by low-energy projectile deuterons, though we do not aim at interpreting particular experiments reported previously. The nuclear fusion processes at low energies are exponentially suppressed due to the Coulomb repulsion. We consider several factors which can enhance the fusion. The most powerful among them is the 'carambole' mechanism of enhancement. It needs that a projectile deuteron and a target deuteron undergo a chain of preliminary elastic collisions between themselves and nuclei of Environment. These collisions effectively convert the fixed-target process into a fusion reaction with colliding beams. This reduces the exponent of the factor that describes penetration through the Coulomb barrier by a factor 21/2, thus drastically, by many orders of magnitude (1011,) increasing the probability. We also calculate increase of the fusion probability given by two other mechanisms by the motion of a bound target deuteron in a solid and by stimulation of this motion by the Coulomb field of a projectile. The later effect we call the 'ping-pong' mechanism. The factor which gives increase for the fusion probability for the three considered mechanisms is illustrated. For low energies the 'carambole' mechanism dominates, producing very strong effect. We expect it to be most efficient in compounds with target deuterons localized in the vicinity of heavy atoms. The electric fields in non-equilibrium processes (like chemical reactions, where cracks in solids or cavities in liquids) or in ferroelectric materials may accelerate deuterons creating the beam-like situation. The beam-like problem may also arise in laser-induced fusion where ions are accelerated due to the laser field and the interaction with electrons
Phase transitions in high excited nuclear matter
International Nuclear Information System (INIS)
This work is a study of the mechanism of thermal multifragmentation, which takes place in collisions of light relativistic projectiles with heavy targets. This is a new multibody decay process of very hot nuclei (target spectator) with emission of a number of intermediate mass fragments (IMF, 2 4He and 12C with Au. The main results are the following: - The mean IMF multiplicity () saturates at 2.2 ± 0.2.This fact cannot be rendered by the traditional approach with the intranuclear cascade (INC) followed by Statistical Multifragmentation Models (SMM). Considering the expansion phase between two parts of the calculations, the excitation energies and the residual masses are empirically modified to obtain agreement with the measured IMF- multiplicities. The mean excitation energy is found to be around 500 MeV for the beam energies above 5 GeV. This modified model is denoted as INC + α + SMM where α indicates the preequilibrium processes. - The expansion is driven by the thermal pressure. It is larger for 4He and 12C induced collisions because of higher initial temperature. The kinetic energy spectra of IMF become harder and the expansion flow is visible. The total flow energy of the system is estimated to be around 115 MeV both for the He and the carbon beams. - The analysis of the data reveals very interesting information on the fragment space distribution inside the break-up volume. Heavier IMF are formed predominately in the interior of the fragmenting nucleus possibly due to a density gradient. This conclusion is in contrast to the predictions of the Statistical Multifragmentation Model (SMM). - This study of the multifragmentation using a range of projectiles demonstrates a transition from pure '' thermal decay '' (for p + Au collisions) to disintegration '' completed by '' the onset of a collective flow for the heavier projectiles. Nevertheless, in case of reaction caused by fast protons the decay mechanism should be considered as a thermal multifragmentation. - The time scale of the thermal multifragmentation in p + Au collision at 8.1 GeV has been measured for the first time (by the analysis of IMF-IMF angular correlations). The mean decay time of the fragmenting system was found to be τ = (50 ± 18) fm/c in accordance with the scenario of a '' simultaneous '' multibody decay of a hot and expanded nuclear system. The measured time-scale is close to that for the density fluctuation in the diluted nuclear system. Hence, the thermal multifragmentation can be interpreted as the first order nuclear liquid-fog phase transition in the spinodal region. - Characteristic temperature Tf is less than Tc - critical temperature for the liquid-gas phase transition. Tc -critical temperature for the liquid-gas phase transition is found to be (17 ± 2) MeV, which is significantly larger than the temperature of fragmenting system (5 - 6 MeV). This is a very important observation in favour of the mechanism of spinodal disintegration. - It is concluded that the decay process of hot nuclei is characterized by two size parameters: transition state and freeze-out volumes. The IMF emission time is related to the mean rupture time at the multi-scission point, which corresponds to the kinetic freeze-out configuration. (author)
Climate Change, Nuclear Power and Nuclear Proliferation: Magnitude Matters
Energy Technology Data Exchange (ETDEWEB)
Robert J. Goldston
2010-03-03
Integrated energy, environment and economics modeling suggests electrical energy use will increase from 2.4 TWe today to 12 TWe in 2100. It will be challenging to provide 40% of this electrical power from combustion with carbon sequestration, as it will be challenging to provide 30% from renewable energy sources. Thus nuclear power may be needed to provide ~30% by 2100. Calculations of the associated stocks and flows of uranium, plutonium and minor actinides indicate that the proliferation risks at mid-century, using current light-water reactor technology, are daunting. There are institutional arrangements that may be able to provide an acceptable level of risk mitigation, but they will be difficult to implement. If a transition is begun to fast-spectrum reactors at mid-century, without a dramatic change in the proliferation risks of such systems, at the end of the century proliferation risks are much greater, and more resistant to mitigation. The risks of nuclear power should be compared with the risks of the estimated 0.64oC long-term global surface-average temperature rise predicted if nuclear power were replaced with coal-fired power plants without carbon sequestration. Fusion energy, if developed, would provide a source of nuclear power with much lower proliferation risks than fission.
Climate Change, Nuclear Power and Nuclear Proliferation: Magnitude Matters
International Nuclear Information System (INIS)
Integrated energy, environment and economics modeling suggests electrical energy use will increase from 2.4 TWe today to 12 TWe in 2100. It will be challenging to provide 40% of this electrical power from combustion with carbon sequestration, as it will be challenging to provide 30% from renewable energy sources. Thus nuclear power may be needed to provide ∼30% by 2100. Calculations of the associated stocks and flows of uranium, plutonium and minor actinides indicate that the proliferation risks at mid-century, using current light-water reactor technology, are daunting. There are institutional arrangements that may be able to provide an acceptable level of risk mitigation, but they will be difficult to implement. If a transition is begun to fast-spectrum reactors at mid-century, without a dramatic change in the proliferation risks of such systems, at the end of the century proliferation risks are much greater, and more resistant to mitigation. The risks of nuclear power should be compared with the risks of the estimated 0.64 C long-term global surface-average temperature rise predicted if nuclear power were replaced with coal-fired power plants without carbon sequestration. Fusion energy, if developed, would provide a source of nuclear power with much lower proliferation risks than fission.
Open charm tomography of cold nuclear matter
Vitev, I; Johnson, M B; Qiu, J W
2006-01-01
We study the relative contribution of partonic sub-processes to D meson production and D meson-triggered inclusive di-hadrons to lowest order in perturbative QCD. While gluon fusion dominates the creation of large angle DD-bar pairs, charm on light parton scattering determines the yield of single inclusive D mesons. The distinctly different non-perturbative fragmentation of c quarks into D mesons versus the fragmentation of quarks and gluons into light hadrons results in a strong transverse momentum dependence of anticharm content of the away-side charm-triggered jet. In p+A reactions, we calculate and resum the coherent nuclear-enhanced power corrections from the final state partonic scattering in the medium. We find that single and double inclusive open charm production can be suppressed as much as the yield of neutral pions from dynamical high-twist shadowing. Effects of energy loss in p+A collisions are also investigated phenomenologically and may lead to significantly weaker transverse momentum dependenc...
Deuteron lifetime in hot and dense nuclear matter near equilibrium
International Nuclear Information System (INIS)
We consider deuteron formation in hot and dense nuclear matter close to equilibrium and evaluate the lifetime of the deuteron fluctuations within the linear response theory. To this end we derive a generalized linear Boltzmann equation where the collision integral is related to equilibrium correlation functions. In this framework we then utilize finite temperature Green functions to evaluate the collision integrals. The elementary reaction cross section is evaluated within the Faddeev approach that is suitably modified to reflect the properties of the surrounding hot and dense matter. copyright 1997 The American Physical Society
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, ρc turns out about nine times the saturation density, ρ0 for the value of the gluon condensate in vacuum =0.012 GeV4. For neutron matter ρc∼8.5ρ0. The dependence of the critical density on the value of the gluon condensate in vacuum is studied
Initial-state splitting kernels in cold nuclear matter
Ovanesyan, Grigory; Vitev, Ivan
2015-01-01
We derive medium-induced splitting kernels for energetic partons that undergo interactions in dense QCD matter before a hard-scattering event at large momentum transfer $Q^2$. Working in the framework of the effective theory ${\\rm SCET}_{\\rm G}\\,$, we compute the splitting kernels beyond the soft gluon approximation. We present numerical studies that compare our new results with previous findings. We expect the full medium-induced splitting kernels to be most relevant for the extension of initial-state cold nuclear matter energy loss phenomenology in both p+A and A+A collisions.
Nuclear matter descriptions including quark structure of the hadrons
International Nuclear Information System (INIS)
It is nowadays well established that nucleons are composite objects made of quarks and gluons, whose interactions are described by Quantum chromodynamics (QCD). However, because of the non-perturbative character of QCD at the energies of nuclear physics, a description of atomic nuclei starting from quarks and gluons is still not available. A possible alternative is to construct effective field theories based on hadronic degrees of freedom, in which the interaction is constrained by QCD. In this framework, we have constructed descriptions of infinite nuclear matter in relativistic mean field theories taking into account the quark structure of hadrons. In a first approach, the in medium modifications of mesons properties is dynamically obtained in a Nambu-Jona-Lasinio (NJL) quark model. This modification is taken into account in a relativistic mean field theory based on a meson exchange interaction between nucleons. The in-medium modification of mesons masses and the properties of infinite nuclear matter have been studied. In a second approach, the long and short range contributions to the in-medium modification of the nucleon are determined. The short range part is obtained in a NJL quark model of the nucleon. The long range part, related to pions exchanges between nucleons, has been determined in the framework of Chiral Perturbation theory. These modifications have been used to constrain the couplings of a point coupling relativistic mean field model. A realistic description of the saturation properties of nuclear matter is obtained. (author)
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 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
Relativistic mean-field hadronic models under nuclear matter constraints
Dutra, M.; Lourenço, O.; Avancini, S. S.; Carlson, B. V.; Delfino, A.; Menezes, D. P.; Providência, C.; Typel, S.; Stone, J. R.
2014-11-01
Background: The microscopic composition and properties of infinite hadronic matter at a wide range of densities and temperatures have been subjects of intense investigation for decades. The equation of state (EoS) relating pressure, energy density, and temperature at a given particle number density is essential for modeling compact astrophysical objects such as neutron stars, core-collapse supernovae, and related phenomena, including the creation of chemical elements in the universe. The EoS depends not only on the particles present in the matter, but, more importantly, also on the forces acting among them. Because a realistic and quantitative description of infinite hadronic matter and nuclei from first principles in not available at present, a large variety of phenomenological models has been developed in the past several decades, but the scarcity of experimental and observational data does not allow a unique determination of the adjustable parameters. Purpose: It is essential for further development of the field to determine the most realistic parameter sets and to use them consistently. Recently, a set of constraints on properties of nuclear matter was formed and the performance of 240 nonrelativistic Skyrme parametrizations was assessed [M. Dutra et al., Phys. Rev. C 85, 035201 (2012), 10.1103/PhysRevC.85.035201] in describing nuclear matter up to about three times nuclear saturation density. In the present work we examine 263 relativistic-mean-field (RMF) models in a comparable approach. These models have been widely used because of several important aspects not always present in nonrelativistic models, such as intrinsic Lorentz covariance, automatic inclusion of spin, appropriate saturation mechanism for nuclear matter, causality, and, therefore, no problems related to superluminal speed of sound in medium. Method: Three different sets of constraints related to symmetric nuclear matter, pure neutron matter, symmetry energy, and its derivatives were used. The first set (SET1) was the same as used in assessing the Skyrme parametrizations. The second and third sets (SET2a and SET2b) were more suitable for analysis of RMF and included, up-to-date theoretical, experimental and empirical information. Results: The sets of updated constraints (SET2a and SET2b) differed somewhat in the level of restriction but still yielded only 4 and 3 approved RMF models, respectively. A similarly small number of approved Skyrme parametrizations were found in the previous study with Skyrme models. An interesting feature of our analysis has been that the results change dramatically if the constraint on the volume part of the isospin incompressibility (Kτ ,v) is eliminated. In this case, we have 35 approved models in SET2a and 30 in SET2b. Conclusions: Our work provides a new insight into application of RMF models to properties of nuclear matter and brings into focus their problematic proliferation. The assessment performed in this work should be used in future applications of RMF models. Moreover, the most extensive set of refined constraints (including nuclear matter and finite-nuclei-related properties) should be used in future determinations of new parameter sets to provide models that can be used with more confidence in a wide range of applications. Pointing to reasons for the many failures, even of the frequently used models, should lead to their improvement and to the identification of possible missing physics not included in present energy density functionals.
Nuclear equation of state in the MIT bag crystal model for nuclear matter
International Nuclear Information System (INIS)
We developed the MIT bag crystal model for nuclear matter in two aspects. First, we proved a ??=4 selection rule in the harmonic expansion of quark wave function by group theory. It enables us to push the maximum Dirac quantum number ?m up from 7 to 15, therefore improving our calculation for the energy band and wave functions of quarks. Then, by a multipole expansion of the color fields we calculate the color interaction energy between quarks. These developments enable us to calculate the energy per nucleon in nuclear matter as done previously for a free nucleon. A nuclear equation of state is derived
A Modified Pion-Rho-Omega Mesonic Lagrangian in Nuclear Matter
International Nuclear Information System (INIS)
We present an in-medium modified effective Lagrangian which describes the pion, rho- and omega mesons and the corresponding soliton properties in nuclear matter. We discuss possible modifications of ?- and ?-meson properties in nuclear matter. In particular, the masses of vector mesons are shown to decrease about 30% at normal nuclear matter density within the present approach. (author)
Low densities in nuclear and neutron matters and in the nuclear surface
Baldo, M; Maieron, C.; SchucK, P.; Vinas, X
2004-01-01
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 throughout the mass ta...
Climate Change, Nuclear Power and Nuclear Proliferation: Magnitude Matters
Energy Technology Data Exchange (ETDEWEB)
Robert J. Goldston
2011-04-28
Integrated energy, environment and economics modeling suggests that worldwide electrical energy use will increase from 2.4 TWe today to ~12 TWe in 2100. It will be challenging to provide 40% of this electrical power from combustion with carbon sequestration, as it will be challenging to provide 30% from renewable energy sources derived from natural energy flows. Thus nuclear power may be needed to provide ~30%, 3600 GWe, by 2100. Calculations of the associated stocks and flows of uranium, plutonium and minor actinides indicate that the proliferation risks at mid-century, using current light-water reactor technology, are daunting. There are institutional arrangements that may be able to provide an acceptable level of risk mitigation, but they will be difficult to implement. If a transition is begun to fast-spectrum reactors at mid-century, without a dramatic change in the proliferation risks of such systems, at the end of the century global nuclear proliferation risks are much greater, and more resistant to mitigation. Fusion energy, if successfully demonstrated to be economically competitive, would provide a source of nuclear power with much lower proliferation risks than fission.
Climate Change, Nuclear Power and Nuclear Proliferation: Magnitude Matters
International Nuclear Information System (INIS)
Integrated energy, environment and economics modeling suggests that worldwide electrical energy use will increase from 2.4 TWe today to ∼12 TWe in 2100. It will be challenging to provide 40% of this electrical power from combustion with carbon sequestration, as it will be challenging to provide 30% from renewable energy sources derived from natural energy flows. Thus nuclear power may be needed to provide ∼30%, 3600 GWe, by 2100. Calculations of the associated stocks and flows of uranium, plutonium and minor actinides indicate that the proliferation risks at mid-century, using current light-water reactor technology, are daunting. There are institutional arrangements that may be able to provide an acceptable level of risk mitigation, but they will be difficult to implement. If a transition is begun to fast-spectrum reactors at mid-century, without a dramatic change in the proliferation risks of such systems, at the end of the century global nuclear proliferation risks are much greater, and more resistant to mitigation. Fusion energy, if successfully demonstrated to be economically competitive, would provide a source of nuclear power with much lower proliferation risks than fission.
Chiral symmetry and nuclear matter equation of state
Indian Academy of Sciences (India)
A B Santra
2001-08-01
We investigate the effect on the nuclear matter equation of state (EOS) due to modiﬁcation of meson and nucleon parameters in nuclear medium as a consequence of partial restoration of chiral symmetry. To get the EOS, we have used Brueckner–Bethe–Golstone formalism with Bonn- potential as two-body interaction and QCD sum rule and Brown–Rho scaling prescriptions for modiﬁcation of hadron parameters. We ﬁnd that EOS is very much sensitive to the meson parameters. We can ﬁt, with two body interaction alone, both the saturation density and the binding energy per nucleon.
Determination of nuclear-matter temperature and density
International Nuclear Information System (INIS)
Some of the things learned about nuclear matter under extreme conditions during the past few years in relativistic heavy ion studies are reviewed. Two developments are discussed. The completion of analyses and publication of results from the impact parameter selected, single-particle inclusive experiments have proven to be important. Preliminary results from the new generation of two-particle correlation and particle-exclusive measurements, especially those using streamer chambers, look even more definitive. Also the measurement of more exotic ejectiles with long mean free paths in nuclear matter promises to provide more basic information. Calculations are offering real guidance and are providing explanations of high energy collisions. The Monte Carlo and intranuclear cascade calculations discussed are especially informative
Electric-dipole sum rule in nuclear matter
Fabrocini, A.; Fantoni, S.
1985-03-01
The enhancement factor K in the electric-dipole sum rule for some realistic models of symmetrical nuclear matter is calculated using variational theory. The nuclear-matter wave function used contains central, spin, isospin, tensor and spin-orbit pair correlations. The non-central correlations, particularly the tensor one, give the major contribution to K. At experimental equilibrium density K. turns out to be ≈ 1.8, of which 65% comes from OPEP and 30% from the short-range part of the interaction. The two-pion-exchange three-nucleon interaction contributes ≈ 0.2% and is cancelled, to a large extent, by the contribution due to the intermediate-range two-body potential. The relationship of the summed oscillator strength with the effective mass is also discussed.
Electric-dipole sum rule in nuclear matter
International Nuclear Information System (INIS)
The enhancement factor K in the electric-dipole sum rule for some realistic models of symmetrical nuclear matter is calculated using variational theory. The nuclear-matter wave function used contains central, spin, isospin, tensor and spin-orbit pair correlations. The non-central correlations, particularly the tensor one, give the major contribution of K. At experimental equilibrium density K turns out to be proportional 1.8 of which 65% comes from OPEP and 30% from the short-range part of the interaction. The two-pion-exchange three-nucleon interaction contributes proportional0.2% and is cancelled, to a large extent, by the contribution due to the intermediate-range two-body potential. The relationship of the summed oscillator strength with the effective mass is also discussed. (orig.)
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 α(J) sym, (b) the symmetry energy at supra-saturation densities, and (c) the radius of neutron stars.
From nuclear matter to finite nuclei. Pt. 2
International Nuclear Information System (INIS)
We discuss various relativistic models describing ground-state properties of spherical nuclei, are discussed. Relativistic mean-field and Hartree-Fock theories, which serve as a startingpoint for subsequent models, are reviewed. Using a density-dependent parametrization of the Dirac-Brueckner G-matrix in nuclear matter, we achieve an effective Dirac-Brueckner-Hartree-Fock model for finite nuclei. Finite nuclei results obtained with this model are compared with the less advanced Density-Dependent Mean-Field model, which simulates Dirac-Brueckner calculations for nuclear matter as well. It is shown that the effective Dirac-Brueckner-Hartree-Fock approach most successfully reproduces experimental data concerning spherical nuclei. (orig.)
Relativistic nuclear matter with alternative derivative coupling models
International Nuclear Information System (INIS)
Effective Lagrangians involving nucleons coupled to scalar and vector fields are investigated within the framework of relativistic mean-field theory. The study presents the traditional Walecka model and different kinds of scalar derivative coupling 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 gives 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 of finite temperature at zero density. (author)
Three- and four-body correlations in nuclear matter
International Nuclear Information System (INIS)
Few-nucleon correlations in nuclear matter at finite densities and temperatures are explored. Using the Dyson-equation approach leads to effective few-body equations that include self-energy corrections and Pauli blocking factors in a systematic way. Examples given are the nucleon-deuteron in-medium reaction rates, few-body bound states including the α-particle, and α-particle condensation. Refs. 17 (author)
Heating of nuclear matter and multifragmentation : antiprotons vs. pions.
Energy Technology Data Exchange (ETDEWEB)
Back, B.; Beaulieu, L.; Breuer, H.; Gushue, S.; Hsi, W.-C.; Korteling, R. G.; Kwiatkowski, K.; Laforest, R.; Lefort, T.; Martin, E.; Pienkowski, L.; Ramakrishnan, E.; Remsberg, L. P.; Rowland, D.; Ruangma, A.; Viola, V. E.; Winchester, E.; Yennello, S. J.
1999-05-03
Heating of nuclear matter with 8 GeV/c {bar p} and {pi}{sup {minus}} beams has been investigated in an experiment conducted at BNL AGS accelerator. All charged particles from protons to Z {approx_equal} 16 were detected using the Indiana Silicon Sphere 4{pi} array. Significant enhancement of energy deposition in high multiplicity events is observed for antiprotons compared to other hadron beams. The experimental trends are qualitatively consistent with predictions from an intranuclear cascade code.
Heating of nuclear matter and multifragmentation: antiprotons vs. pions
International Nuclear Information System (INIS)
Heating of nuclear matter with 8 GeV/c bar p and ?- beams has been investigated in an experiment conducted at BNL AGS accelerator. All charged particles from protons to Z ? 16 were detected using the Indiana Silicon Sphere 4? array. Significant enhancement of energy deposition in high multiplicity events is observed for antiprotons compared to other hadron beams. The experimental trends are qualitatively consistent with predictions from an intranuclear cascade code
Compression modes and the nuclear matter incompressibility coefﬁcient
Indian Academy of Sciences (India)
Shalom Shlomo
2001-08-01
We review the current status of the nuclear matter ( = and no Coulomb interaction) incompressibility coefﬁcient, , and describe the theoretical and the experimental methods used to determine from properties of compression modes in nuclei. In particular we consider the long standing problem of the conﬂicting results obtained for , deduced from experimental data on excitation cross sections for the isoscalar giant monopole resonance (ISGMR) and data for the isoscalar giant dipole resonance (ISGDR).
Detector developing for directional dark matter search with nuclear emulsion
International Nuclear Information System (INIS)
We are planing the directional dark matter search experiment with nuclear emulsion. Recoiled atoms inside of the emulsion fly several hundred nm, and it is too short to detect with usual emulsion. Fine crystal emulsion was needed to detect such tracks. We developed new method to produce them and succeeded to make crystals small as 20 nm at the minimum size. We also study several methods to improve sensitivity and reduce background noise to survey very interesting cross section region
Investigation of the organic matter in inactive nuclear tank liquids
International Nuclear Information System (INIS)
Environmental Protection Agency (EPA) methodology for regulatory organics fails to account for the organic matter that is suggested by total organic carbon (TOC) analysis in the Oak Ridge National Laboratory (ORNL) inactive nuclear waste-tank liquids and sludges. Identification and measurement of the total organics are needed to select appropriate waste treatment technologies. An initial investigation was made of the nature of the organics in several waste-tank liquids. This report details the analysis of ORNL wastes
Radial densities of nuclear matter and charge via moment methods
International Nuclear Information System (INIS)
In this report I will discuss some initial efforts in our program to describe radial densities of nuclear matter and charge with the use of moment methods. A brief introduction to trace reduction formulas and computation problems along with proposed methods to overcome them will be given. This will be followed by a general discussion on computation of expectation values using moment methods with particular emphasis on formulation for the radial density applications
Field theoretic treatment of pion-nuclear matter elastic scattering
International Nuclear Information System (INIS)
Pion-nucleon amplitudes of a field theoretical origin are constructed as a semi-phenomenological input into the pion-nuclear matter problem. The amplitudes are obtained from a scattering equation. The new scattering equation approximates the static one meson low equation as to its analytical structure and crossing symmetry, but differs from the Low equation in that a closed form solution is possible. The resulting t-matrices depend on an arbitrary form factor as do those of the one meson Low Equation, and the scattering amplitudes can therefore be fit to the experimental data by an extension of existing inverse problems. The resulting t-matrix is corrected for the effects of noninteracting nuclear matter by an appropriate extension of the new scattering equation presented, and then entered into a field theoretical pion-nuclear matter optical potential that employs Dyson's equation for the irreducible self energy of the pion. It is found that while the off shell extension of the two-body t-matrix is affected only slightly by the results of the new scattering equation, the optical potential thus obtained has some novel features
Nuclear spin resonances in double beta decays and dark matters
International Nuclear Information System (INIS)
In this paper, as the experiment using the spin in atomic nuclei as the experimental means, the double data decay and the experiment for searching for dark matters by Ejiri group of Osaka University are reported. Double beta decay is the phenomenon in which beta decay occurs twice successively in atomic nuclei, and theoretically a number of decay modes are considered. In double beta decay, two beta rays (electrons) and two neutrinos are emitted, therefore, the energy spectra of beta ray become continuous. The probability of decay, the effect of neutrino emission and others are discussed. The detector (ELEGANTS V) that the group of Osaka University uses for the measurement is introduced. The thin film specimens of Mo are used. The spectrum is shown, and the half life was obtained. The results are reported. The existence of space dark matters was predicted, but it has not been found. The application of NaI detector to the search for dark matters has been investigated. NaI consists of the nuclei having finite nuclear spin, and is suitable to the search for the dark matters of spin coupling type. The limit for the existence of dark matters was determined. (K.I.)
Jezghani, Margaret; Phenix Collaboration
2015-10-01
A major objective in the field of high-energy nuclear physics is to quantify and characterize the quark-gluon plasma formed in relativistic heavy-ion collisions. The ϕ meson is an excellent probe for studying this hot and dense state of nuclear matter due to its very short lifetime, and the absence of strong interactions between muons and the surrounding hot hadronic matter makes the ϕ to dimuon decay channel particularly interesting. Since the ϕ meson is composed of a strange and antistrange quark, its nuclear modification in heavy-ion collisions may provide insight on strangeness enhancement in-medium. Additionally, the rapidity dependence of ϕ production in asymmetric heavy-ion collisions provides a unique means to study the entanglement of hot and cold nuclear matter effects. In this talk, we present the measurement of ϕ meson production and nuclear modification in asymmetric Cu+Au heavy-ion collisions at √{s}NN = 200 GeV at both forward (Cu-going direction) and backward (Au-going direction) rapidities. This material is based upon work supported by the U.S. Department of Energy (DOE), Office of Science, Office of Workforce Development for Teachers and Scientists, Office of Science Graduate Student Research (SCGSR) award program.
Theory of superfluid states with singlet and triplet types of pairing in nuclear matter
International Nuclear Information System (INIS)
The paper presents the results of investigation of superfluid states in a two-component Fermi liquid in the framework of the Fermi liquid approach. Particular attention is paid to superfluid states in nuclear matter which are characterized by the superposition of singlet and triplet types of pairing in spin and isospin spaces. The authors have formulated the basic points of the Fermi liquid approach which are used in the study of superfluidity in nuclear matter with the superposition of singlet and triplet types of pairing. Derivation of the system of self-consistency equations and their solution are presented. For concrete calculations the interaction in the Skyrme model is taken. Using this model the conditions for the existence of the considered states are determined. These conditions impose certain constraints on the potential of interaction and on the density of particles in the system. It is shown that the states with a complete set of nonzero order parameters are realized only in a narrow density range, whose width and position in the density scale depend on the choice of a particular Skyrme force. Considered are 18 different parameterizations, and indicated is for which of them the studied types of superfluid states may appear The problem of stability of the states with superposition of singlet and triplet types of pairing is studied. It is shown that the lowest value of the thermodynamic potential corresponds to purely triplet states, then in order of increasing there are the thermodynamic potential of purely singlet states, and mixed singlet-triplet states. The case of unitary states is considered separately. For these states the solutions of the self-consistency equations are analyzed too. The density range for these states is defined and it is shown that this range is different than from that which corresponds to the nonunitary states. In addition, studied is the problem of the existence of unitary superfluid states with the superposition of singlet and triplet superfluidity in the case of asymmetrical nuclear matter. It is shown that the appearance of asymmetry causes the unitarity of superfluid states in nuclear matter to be broken.
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
Nuclear Transparency Effect in the Strongly Interacting Matter
Ajaz, M; Abdinov, O B; Zaman, Ali; Khan, K H; Wazir, Z; Khalilova, Sh
2012-01-01
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.
The effective action approach applied to nuclear matter (1)
International Nuclear Information System (INIS)
Within the framework of the Walecka model (QHD-I) the application of the Cornwall-Jackiw-Tomboulis (CJT) effective action to nuclear matter is presented. The main feature is the treating of the meson condensates for the system of finite nuclear density. The system of couple Schwinger-Dyson (SD) equations is derived. It is shown that SD equations for sigma-omega mixings are absent in this formalism. Instead, the energy density of the nuclear ground state does explicitly contain the contributions from the ring diagrams, amongst others. In the bare-vertex approximation, the expression for energy density is written down for numerical computation in the next paper. (author). 14 refs, 3 figs
Mondal, C; De, J N
2015-01-01
Elements of nuclear symmetry energy evaluated from different energy density functionals parametrized by fitting selective bulk properties of few representative nuclei are seen to vary widely. Those obtained from experimental data on nuclear masses across the periodic table, however, show that they are better constrained. A possible direction in reconciling this paradox may be gleaned from comparison of results obtained from use of the binding energies in the fitting protocol within a microscopic model with two sets of nuclei, one a representative standard set and another where very highly asymmetric nuclei are additionally included. A covariance analysis reveals that the additional fitting protocol reduces the uncertainties in the nuclear symmetry energy coefficient, its slope parameter as well as the neutron-skin thickness in $^{208}$Pb nucleus by $\\sim 50\\%$. The central values of these entities are also seen to be slightly reduced.
Mondal, C.; Agrawal, B. K.; De, J. N.
2015-08-01
Elements of nuclear symmetry energy evaluated from different energy density functionals parametrized by fitting selective bulk properties of few representative nuclei are seen to vary widely. Those obtained from experimental data on nuclear masses across the periodic table, however, show that they are better constrained. A possible direction in reconciling this paradox may be gleaned from comparison of results obtained from use of the binding energies in the fitting protocol within a microscopic model with two sets of nuclei, one a representative standard set and another where very highly asymmetric nuclei are additionally included. A covariance analysis reveals that the additional fitting protocol reduces the uncertainties in the nuclear symmetry energy coefficient, its slope parameter, as well as the neutron-skin thickness in 208Pb nucleus by ˜50 % . The central values of these entities are also seen to be slightly reduced.
Equation of state for nuclear matter based on density dependent effective interaction
Basu, D. N.
2003-01-01
An interesting method of obtaining equation of state for nuclear matter, from a density dependent M3Y interaction, by minimizing the energy per nucleon is described. The density dependence parameters of the interaction are obtained by reproducing the saturation energy per nucleon and the saturation density of spin and isospin symmetric cold infinite nuclear matter. The nuclear matter equation of state thus obtained is then used to calculate the pressure, the energy density, the nuclear incomp...
Converting of Matter to Nuclear Energy by AB-Generator
Directory of Open Access Journals (Sweden)
Alexander Bolonkin
2009-01-01
Full Text Available Problem statement: Researcher offered a new nuclear generator which allowed to convert any matter to nuclear energy in accordance with Einstein equation E = mc2. The method was based upon tapping the energy potential of a Micro Black Hole (MBH and Hawking radiation created by this MBH. Researcher did not meet the idea and its research in literature to develop the method for getting a cheap energy. Approach: As is well-known, vacuum continuously produced virtual pairs of particles and antiparticles, in particular, photons and anti-photons. MBH event horizon allowed separating them. Anti-photons can be moved to MBH and be annihilated, decreasing mass of MBH, resulting photons leave the MBH neighborhood as Hawking radiation. The offered nuclear generator (named by Researcher as AB-generator utilized Hawking radiation and injected the matter into MBH and kept MBH in a stable state with near-constant mass. Results: AB-generator can be produced gigantic energy outputs and should be cheaper than a conventional electric station by a factor of hundreds of times. One also may be used in aerospace as a photon rocket or as a power source for many vehicles. Conclusion: Many scientists expect Large Hadron Collider at CERN may be produced one MBH every second. A technology to capture them may be developed; than they may be used for the AB-generator.
Is nuclear matter perturbative with low-momentum interactions?
Bogner, S K; Furnstahl, R J; Nogga, A
2005-01-01
The nonperturbative nature of inter-nucleon interactions is explored by varying the momentum cutoff of a two-nucleon potential. Conventional force models, which have large cutoffs, are nonperturbative because of strong short-range repulsion, the iterated tensor interaction, and the presence of bound or nearly-bound states. But for low-momentum interactions with cutoffs around 2 fm^{-1}, the softened potential combined with Pauli blocking leads to corrections in nuclear matter in the particle-particle channel that are well converged at second order in the potential, suggesting that perturbation theory can be used in place of Brueckner resummations. Calculations of nuclear matter using the low-momentum two-nucleon force V_{low k} with a corresponding leading-order three-nucleon (3N) force from chiral effective field theory (EFT) exhibit nuclear binding in the Hartree-Fock approximation, and become less cutoff dependent with the inclusion of the dominant second-order contributions. The role of the 3N force is es...
Is nuclear matter perturbative with low-momentum interactions?
International Nuclear Information System (INIS)
The nonperturbative nature of inter-nucleon interactions is explored by varying the momentum cutoff of a two-nucleon potential. Conventional force models, which have large cutoffs, are nonperturbative because of strong short-range repulsion, the iterated tensor interaction, and the presence of bound or nearly-bound states. But for low-momentum interactions with cutoffs around 2 fm-1, the softened potential combined with Pauli blocking leads to corrections in nuclear matter in the particle-particle channel that are well converged at second order in the potential, suggesting that perturbation theory can be used in place of Brueckner resummations. Calculations of nuclear matter using the low-momentum two-nucleon force Vlowk with a corresponding leading-order three-nucleon (3N) force from chiral effective field theory (EFT) exhibit nuclear binding in the Hartree-Fock approximation, and become less cutoff dependent with the inclusion of the dominant second-order contributions. The role of the 3N force is essential to obtain saturation, and the contribution to the total potential energy is compatible with EFT power-counting estimates
Reducible chiral four-body interactions in nuclear matter
Energy Technology Data Exchange (ETDEWEB)
Kaiser, N.; Milkus, R. [Technische Universitaet Muenchen, Physik-Department T39, Garching (Germany)
2016-01-15
The method of unitary transformations generates five classes of leading-order reducible chiral four-nucleon interactions which involve pion exchanges and a spin-spin contact term. Their first-order contributions to the energy per particle of isospin-symmetric nuclear matter and pure neutron matter are evaluated in detail. For most of the closed four-loop diagrams the occurring integrals over four Fermi spheres can be reduced to easily manageable one- or two-parameter integrals. One finds substantial compensations among the different contributions arising from 2-ring and 1-ring diagrams. Altogether, the net attraction generated by the chiral four-nucleon interaction does not exceed values of -1.3 MeV for densities ρ < 2ρ{sub 0}. (orig.)
Conventional and Unconventional Pairing and Condensates in Dilute Nuclear Matter
Clark, John W; Stein, Martin; Huang, Xu-Guang; Khodel, Victor A; Shaginyan, Vasily R; Zverev, Mikhail V
2016-01-01
This contribution will survey recent progress toward an understanding of diverse pairing phenomena in dilute nuclear matter at small and moderate isospin asymmetry, with results of potential relevance to supernova envelopes and proto-neutron stars. Application of {\\it ab initio} many-body techniques has revealed a rich array of temperature-density phase diagrams, indexed by isospin asymmetry, which feature both conventional and unconventional superfluid phases. At low density there exist a homogeneous translationally invariant BCS phase, a homogeneous LOFF phase violating translational invariance, and an inhomogeneous translationally invariant phase-separated BCS phase. The transition from the BCS to the BEC phases is characterized in terms of the evolution, from weak to strong coupling, of the pairing gap, condensate wave function, and quasiparticle occupation numbers and spectra. Additionally, a schematic formal analysis of pairing in neutron matter at low to moderate densities is presented that establishes...
Nucleon-nucleon correlations in dense nuclear matter
International Nuclear Information System (INIS)
In this thesis new results on the problematics of the formation of nucleon-nucleon correlations in nuclear matter could be presented. Starting from a general study of the two-particle problem in matter we studied the occurrence of a suprafluid phase (pair condensate of nucleons). The Gorkov decoupling by means of anomalous Green functions was generalized, so that also Cooper pairs with spin 1 (triplet pairing) can be described. A generalized gap equation resulted, which permits to determine the order parameters of the suprafluied phase in arbitrary channels of the nucleon-nucleon scattering states. This equation was solvd in the 1S0-, in the 3P2-3F2, and in the 3S1-3D1 channel under application of realistic nucleon-nucleon potentials. The behaviour of the resulting gap parameters in the single channels was studied as function of density and temperature. (orig.)
Reducible chiral four-body interactions in nuclear matter
Kaiser, N
2015-01-01
The method of unitary transformations generates five classes of leading-order reducible chiral four-nucleon interactions which involve pion-exchanges and a spin-spin contact-term. Their first-order contributions to the energy per particle of isospin-symmetric nuclear matter and pure neutron matter are evaluated in detail. For most of the closed four-loop diagrams the occurring integrals over four Fermi-spheres can be reduced to easily manageable one- or two-parameter integrals. One observes substantial cancelations among the different contributions arising from 2-ring and 1-ring diagrams. Altogether, the net attraction generated by the chiral four-nucleon interaction does not exceed values of $-1.3$\\,MeV for densities $\\rho<2\\rho_0$.
Sakuragi, Y
2016-01-01
Yoichiro Nambu put a great foot print in nuclear physics in the era of its fundamental developments including his pioneering insight into essential ingredients of repulsive core of nuclear force and its relation to the saturation of nuclear matter. The present review article focuses onto recent developments of the interaction models between colliding nuclei in terms of Brueckner's G-matrix theory staring from realistic nuclear forces and the saturation property of symmetric nuclear matter as well as neutron-star matter. A recently proposed unique scenario of extracting the saturation property of nuclear matter and stiffness of neutron stars through the analysis of nucleus-nucleus elastic scattering in laboratories is presented in some detail.
Finite temperature RPA in symmetric nuclear matter with Skyrme interactions
International Nuclear Information System (INIS)
We investigate the RPA response for thermally excited nuclear matter interacting through Skyrme interactions. Closed analytical expressions are obtained for the dynamic susceptibility in each spin-isopspin channel. We compute the strength as a function of energy, transferred momentum and temperature, and examine the evolution of collective states, when present. The energy weighted sum rules Mk, for k = -1, 1 and 3 are also shown to possess explicit expressions as functions of both momentum and temperature. It is seen that thermal effects on the susceptibility are as important as dynamical ones associated to momentum transfer, at least for temperatures as high as 20% of the Fermi energy. (orig.)
Mass shift of sigma-Meson in Nuclear Matter
Morones-Ibarra, J R; Santos-Guevara, Ayax; Padilla, Felipe Robledo
2010-01-01
The propagation of sigma meson in nuclear matter is studied in the Walecka model, assuming that the sigma couples to a pair of nucleon-antinucleon states and to particle-hole states, including the in medium effect of sigma-omega mixing. We have also considered, by completeness, the coupling of sigma to two virtual pions. We have found that the sigma meson mass decreases respect to its value in vacuum and that the contribution of the sigma omega mixing effect on the mass shift is relatively small.
Dynamical structure factor of correlated hot nuclear matter
Röpke, G.; Morawetz, K.; Alm, T.
1993-08-01
Starting from a quantum statistical approach to the density-density response function, its relation to the compressibility and to the equation of state of nuclear matter at finite temperature is investigated. In particular, the contribution of two-particle correlations to the dynamical structure factor is taken into account, which becomes important at low temperatures in the low-density limit. It is shown that this treatment for the structure factor is consistent with the equation of state up to the second virial coefficient.
Equidistant structure and effective nucleon mass in nuclear matter
International Nuclear Information System (INIS)
The effective nucleon mass of the Equidistant Multi-Layer Structure (EMULS) is discussed self-consistently. In the density region where the Fermi gas state in nuclear matter is unstable against the density fluctuation, the EMULS gives lower binding energy. It is, however, shown that such a structure with an ordinary nucleon mass collapses due to too strong attraction. We point out that such a collapse can be avoided by taking account of an effective nucleon mass affected by the localization of nucleons. (author)
Landau-Pomeranchuk-Migdal effect for nuclear matter in QCD
Levin, E
1995-01-01
Soft photon and gluon radiation off a fast quark propagating through nuclear matter is discussed. The close anology between the Landau - Pomeranchuk - Migdal (LPM) effect in QED and the emission of soft gluons, suggested in ref. \\cite{BDPS} for ``hot" plasma, is confirmed and the relation between Mueller's approach and traditional calculations is established. It is shown that perturbative QCD can be applied to take into account the LPM coherent suppression both for photon and gluon induced radiation. The formulae for the photon and gluon radiation densities are presented.
Landau-Pomeranchuck-Migdal effect for nuclear matter in QCD
International Nuclear Information System (INIS)
Soft photon and gluon radiation off a fast quark propagating through nuclear matter is discussed. The close analogy between the Landau-Pomeranchuk - Migdal (LPM) effect in QED and the emission of soft gluons, suggested in ref. [1] for hot plasma, is confirmed and the relation between Mueller's approach and traditional calculations is established. It is shown that perturbative QCD can be applied to take into account the LPM coherent suppression both and gluon induced radiation. The formulae for the photon and gluon radiation densities are presented. (author). 15 refs, 4 figs
Landau-Pomeranchuck-Migdal effect for nuclear matter in QCD
Energy Technology Data Exchange (ETDEWEB)
Levin, Eugene
1995-09-01
Soft photon and gluon radiation off a fast quark propagating through nuclear matter is discussed. The close analogy between the Landau-Pomeranchuk - Migdal (LPM) effect in QED and the emission of soft gluons, suggested in ref. [1] for hot plasma, is confirmed and the relation between Mueller`s approach and traditional calculations is established. It is shown that perturbative QCD can be applied to take into account the LPM coherent suppression both and gluon induced radiation. The formulae for the photon and gluon radiation densities are presented. (author). 15 refs, 4 figs.
Mass shift of σ-meson in nuclear matter
International Nuclear Information System (INIS)
The propagation of σ-meson in nuclear matter is studied in the Walecka model, by assuming that sigma couples to a pair of nucleon-antinucleon states to particle-hole states. The in-medium effect of σ-ω mixing is also studied. For completeness, the coupling of sigma to two virtual pions was also considered. It is found that the σ-meson mass decreases with respect to its value in vacuum and that the contribution of the σ-ω mixing effect on the mass shift is relatively small. (author)
Nuclear matter equation of state and -meson parameters
Indian Academy of Sciences (India)
A B Santra; U Lambardo
2005-01-01
We try to determine phenomenologically the extent of in-medium modification of -meson parameters so that the saturation observables of the nuclear matter equation of state (EOS) are reproduced. To calculate the EOS we have used Brueckner–Bethe–Goldstone formalism with Bonn potential as two-body interaction. We find that it is possible to understand all the saturation observables, namely, saturation density, energy per nucleon and incompressibility, by incorporating in-medium modification of -meson–nucleon coupling constant and -meson mass by a few per cent.
Thermodynamic Equilibrium of Nuclear Matter in General Relativity
Rueda, Jorge A; Xue, S -S; Pugliese, D
2011-01-01
We formulate the set of self-consistent ground-state equilibrium equations for nuclear matter taking into account quantum statistics, electro-weak, and strong interactions, within the framework of general relativity. The strong interaction between nucleons is modeled through the $\\sigma$-$\\omega$-$\\rho$ meson exchange in the context of the extended Walecka model, all duly expressed in general relativity. We demonstrate that the thermodynamic equilibrium condition given by the constancy of the generalized chemical potential of each particle-specie, for short the constancy of the Klein potentials, and by the Tolman's isothermal condition, can be properly generalized to include the contribution of all fields.
International Nuclear Information System (INIS)
Thermodynamically self-consistent class of nuclear matter equations of state are considered. For two different equations of state with deconfinement phase transition the compression shock adiabats are calculated. The shock stability for mixed phase formation is studied. 17 refs.; 4 figs
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
ω meson propagation in dense nuclear matter and collective excitations
International Nuclear Information System (INIS)
The bosonic excitations induced by the ω meson propagation in dense nuclear matter is studied within the framework of random phase approximation. The collective modes are then analyzed by finding the zeros of the relevant dielectric functions. Subsequently we present closed form analytical expressions for the dispersion relations in different kinematical regime. Next, the analytical behaviour of the in-medium effective propagator for the ω meson is examined. This is exploited to calculate the full spectral function for the transverse (T) and longitudinal (L) mode of the ω meson. In addition, various sum rules are constructed for the ω meson spectral density in nuclear medium. Results are then discussed by calculating the residues at the poles and discontinuities across the cuts
Nuclear phase transformations: new states of dense matter
International Nuclear Information System (INIS)
Heavy ion collisions with velocities nearing the quarter of light speed allow us to study the behaviour of nuclear matter under extreme temperature and density conditions. Experimental studies show that the decay of hot nuclei can take the form of the emission of smaller nuclei (nuclear fragmentation) or of the emission of only light particles such as neutrons, hydrogen, or helium nuclei (vaporization). The second process has similarities with liquid-gas phase transformation. Recently 2 new experimental facts have supported the phase transformation interpretation: energy fluctuations and correlations with abnormal amplitudes. Energy fluctuations imply negative values of the specific heat and a negative specific heat is involved in the liquid-gas transformation of any finite system. Abnormal amplitude correlations show the possibility of a spinodal decomposition that, till now, has only been seen in liquid-gas transformation. (A.C.)
Off-Fermi Shell Nucleons in Superdense Nuclear Matter
McGauley, Michael
2011-01-01
Based on recent progress in understanding the nature of two-nucleon (2N) short range correlations (SRCs) we performed world data analysis on inclusive electro-nuclear reactions at large momentum transfer to extract the probabilities of 2N SRCs for 3He, 4H, 12C, 27Al, 56Fe and 197Au nuclei. Using recent observations on strong dominance of proton-neutron SRCs as compared to proton-proton and neutron-neutron correlations we parameterized the obtained probabilities as a function of nuclear density and asymmetry. Using the obtained functional form of the probabilities we estimated the fractions of the off-Fermi shell protons and neutrons in the superdense nuclear matter relevant to neutron stars. Our results indicate that starting at 3-4 nuclear saturation densities the protons with fractional densities x_p={1\\over 9} will populate mostly the high momentum (off-Fermi shell) tail of the momentum distribution while only 20% of the neutrons will be in the high momentum tail. We discuss the implication of our observat...
Open Heavy Flavor in QCD Matter and in Nuclear Collisions
Prino, Francesco
2016-01-01
We review the experimental and theoretical status of open heavy-flavor (HF) production in high-energy nuclear collisions at RHIC and LHC. We first overview the theoretical concepts and pertinent calculations of HF transport in QCD matter, including perturbative and non-perturbative approaches in the quark-gluon plasma, effective models in hadronic matter, as well as implementations of heavy-quark (HQ) hadronization. This is followed by a brief discussion of bulk evolution models for heavy-ion collisions and initial conditions for the HQ distributions which are needed to calculate HF spectra in comparison to observables. We then turn to a discussion of experimental data that have been collected to date at RHIC and LHC, specifically for the nuclear suppression factor and elliptic flow of semileptonic HF decays, D mesons, non-prompt $J/\\psi$ from B-meson decays, and b-jets. Model comparisons to HF data are conducted with regards to extracting the magnitude, temperature and momentum-dependence of HF transport coe...
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
Mukherjee, Abhishek
2008-01-01
We apply the variational theory for fermions at finite temperature and high density, developed in an earlier paper, to symmetric nuclear matter and pure neutron matter. This extension generalizes to finite temperatures, the many body technique used in the construction of the zero temperature Akmal-Pandharipande-Ravenhall equation of state. We discuss how the formalism can be used for practical calculations of hot dense matter. Neutral pion condensation along with the associated isovector spin...
Lectures on Effective Field Theories for Nuclei, Nuclear Matter and Dense Matter
Rho, M
2002-01-01
This note is based on four lectures that I gave at the 10th Taiwan Nuclear Spring School held at Hualien, Taiwan in January 2002. It aims to correlate the old notion of Cheshire Cat Principle developed for elementary baryons to the modern notion of quark-baryon and gluon-meson "continuities" or "dualities" in dilute and dense many-body systems and predict what would happen to mesons when squeezed by nuclear matter to high density as possibly realized in compact stars. Using color-flavor locking in QCD, the vector mesons observed at low density can be described as the Higgsed gluons dressed by cloud of collective modes, i.e., pions just as they are in superdense matter, thus showing the equivalence between hidden $flavor$ gauge symmetry and explicit $color$ gauge symmetry. Instead of going into details of well-established facts, I focus on a variety of novel ideas -- some solid and some less -- that could be confirmed or ruled out in the near future.
J/psi production in proton-nucleus collisions at ALICE: cold nuclear matter really matters
CERN. Geneva
2013-01-01
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...
Nuclear fusion in dense matter: Reaction rate and carbon burning
Gasques, L R; Aguilera, E F; Beard, M; Chamon, L C; Ring, P; Wiescher, M; Yakovlev, D G
2005-01-01
In this paper we analyze the nuclear fusion rate between equal nuclei for all five different nuclear burning regimes in dense matter (two thermonuclear regimes, two pycnonuclear ones, and the intermediate regime). The rate is determined by Coulomb barrier penetration in dense environments and by the astrophysical S-factor at low energies. We evaluate previous studies of the Coulomb barrier problem and propose a simple phenomenological formula for the reaction rate which covers all cases. The parameters of this formula can be varied, taking into account current theoretical uncertainties in the reaction rate. The results are illustrated for the example of the ^{12}C+^{12}C fusion reaction. This reaction is very important for the understanding of nuclear burning in evolved stars, in exploding white dwarfs producing type Ia supernovae, and in accreting neutron stars. The S-factor at stellar energies depends on a reliable fit and extrapolation of the experimental data. We calculate the energy dependence of the S-f...
Lee, Sang Tak; Yang, Boram; Kim, Jin-Yong; Park, Ji-Hyung; Moon, Myeong Hee
2015-08-28
This study demonstrated that asymmetrical flow field-flow fractionation (AF4) coupled with on-line UV and fluorescence detection (FLD) and off-line excitation-emission matrix (EEM) fluorescence spectroscopy can be employed to analyze the influence of microbial metabolic activity on the consumption and production of freshwater organic matter. With the AF4 system, organic matter is on-line enriched during a focusing/relaxation period, which is an essential process prior to separation. Size-fractionated chromophoric and fluorophoric organic materials were simultaneously monitored during the 30-min AF4 separation process. Two fractions of different sizes (dissolved organic matter (DOM) and particulate organic matter (POM)) of freshwater samples from three locations (up-, mid-, and downstream) along the Han River basin of Korea were incubated with the same inoculum for 14 days to analyze fraction-specific alterations in optical properties using AF4-UV-FLD. A comparison of AF4 fractograms obtained from pre- and post-incubation samples revealed that POM-derived DOM were more susceptible to microbial metabolic activity than was DOM. Preferential microbial consumption of protein-like DOM components concurred with enhanced peaks of chromophoric and humic-like fluorescent components, presumably formed as by-products of microbial processing. AF4-UV-FLD combined with off-line identification of microbially processed components using EEM fluorescence spectroscopy provides a powerful tool to study the relationship between microbial activity and composition as well as biodegradability of DOM and POM-derived DOM from different origins, especially for the analysis of chromophoric and fluorophoric organic matter that are consumed and produced by microbial metabolic activity. The proposed AF4 system can be applied to organic matter in freshwater samples having low concentration range (0.3-2.5ppm of total organic carbon) without a pre-concentration procedure. PMID:26233252
Symmetry Energy of Nuclear Matter at Low Densities and Clustering at the Nuclear Surface
International Nuclear Information System (INIS)
We present a density functional theory which connects nuclear matter equation of state, which incorporates clustering at low densities, with clustering in medium and heavy nuclei at the nuclear surface. This explains the large values of symmetry energy reported by Natowitz et al for densities −3 in addition to the binding energies and charge rms radii of 367 spherical nuclei. The present theory which is partly macroscopic competes with other high quality microscopic-macroscopic approaches. Merits of the results with clustering and no-clustering are discussed. We also make connection with realistic interactions (AV18+UIX/IL2) which have been used in ab initio calculations in s- and p-shell nuclei and neutron matter. Theory predicts new situations and regimes to be explored both theoretically and experimentally. It is demonstrated that, due to clustering, the neutron skin thickness reduces significantly.
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)
The dispersion relation of the pion in nuclear matter
International Nuclear Information System (INIS)
We put forward a formalism to calculate the relativistic particle-hole and delta-hole excitation polarization insertion for pion propagator by using the particle-hole-antiparticle representation of nucleon and delta propagators in nuclear matter. The real and the imaginary part of the polarization insertion and the dispersion relation for pion propagator are calculated numerically. We find that the short range correlation enhances the delta-hole excitation but suppresses the particle-hole excitation, it also suppresses the pion condensation. We find that the effect of the short range correlation on the pion dispersion relation depends very much on the form of the short range correlation and the parameters involved. (orig.)
Finite baryon density in lattice simulations and nuclear matter
International Nuclear Information System (INIS)
A simple model for the partition function of an interacting nucleon gas can explain the early onset of the baryon density observed when using staggered fermions on the lattice at finite chemical potential. The onset, which is very sensitive to the number of lightest nucleon states formed, represents the point where condensation into nuclear matter occurs. The lattice simulations have been done with staggered fermions or 4 degenerate valence quarks, which can bind into 40 lightest nucleons for which the model can fit the early onset as found on the lattice for various quark masses. The statistical model contains scalar interactions, producing attractive energies scaling as mN-2, among nucleons which propagate in effective volumes that exclude the hard nucleon cores determined by m?. Extrapolating the number of flavours and masses to the values in nature, where we have 4 lowest nucleon states, the model shows and onset close to the nucleon mass as desired. (orig.)
Dynamics of hot and dense nuclear and partonic matter
International Nuclear Information System (INIS)
The dynamics of hot and dense nuclear matter is discussed from the microscopic transport point of view. The basic concepts of the Hadron-String-Dynamical transport model (HSD)—derived from Kadanoff-Baym equations in phase phase—are presented as well as “highlights” of HSD results for different observables in heavy-ion collisions from 100 A MeV (SIS) to 21 A TeV(RHIC) energies. Furthermore, a novel extension of the HSD model for the description of the partonic phase—the Parton—Hadron-String-Dynamics (PHSD) approach—is introduced. PHSD includes a nontrivial partonic equation of state—in line with lattice QCD—as well as covariant transition rates from partonic to hadronic degrees of freedom. The sensitivity of hadronic observables to the partonic phase is demonstrated for relativistic heavy-ion collisions from the FAIR/NICA up to the RHIC energy regime.
Unstable three dimensional nuclear matter in stochastic mean field approach
International Nuclear Information System (INIS)
A semi-classical stochastic mean-field approach is discussed. In the case of unstable infinite nuclear matter, the characteristic time of the exponential growing of fluctuations and the diffusion coefficients associated to the unstable modes are calculated in the framework of the Boltzmann-Langevin theory. In order to make realistic 3D calculations feasible, the complicated Boltzmann-Langevin theory is suggested to be replaced by a simpler stochastic meanfield approach corresponding to a standard Boltzmann evolution, complemented by a simple noise chosen to reproduce the dynamics of the most unstable modes. Finally, it is explained how to approximately implement this method by simply tuning the noise associated to the use of a finite number of test particles in Boltzmann-like calculations. (authors) 17 refs., 5 figs
International Nuclear Information System (INIS)
The effects of intensified and asymmetric barrier penetration by complex particles exhibiting intrinsic structure are investigated in the framework of the time-dependent mean-field theory using an effective one-dimensional layer geometry and a simplified Skyrme nucleon-nucleon effective interaction. The transmission coefficient D(E) has been investigated as a function of incident energy E anU layer thickness. The appearance of discontinuities in D(E) is discussed in detail. It is argued that quantum corrections to the standard TDHF picture as well as the transition to three dimensions possibly smearing out the discontinuities should not alter the qualitative results. In nearly all considered cases the penetrability is really substantially intensified and the asymmetry effect manifests itself as predicted earlier using a simple quasideuteron model
Neutrino mean free paths in cold symmetric nuclear matter
International Nuclear Information System (INIS)
The neutrino mean free paths (NMFP) for scattering and absorption in cold symmetric nuclear matter (SNM) are calculated using two-body effective interactions and one-body effective weak operators obtained from realistic models of nuclear forces using correlated basis theory. The infinite system is modeled in a box with periodic boundary conditions and the one particle-hole (p-h) response functions are calculated using the Tamm-Dancoff approximation (TDA). For the densities ρ=(1/2), 1 (3/2)ρ0, where ρ0 is the equilibrium density of SNM, the strength of the response is shifted to higher energy transfers when compared to a noninteracting Fermi gas (FG). This and the weakness of effective operators compared to the bare operators, significantly reduces the cross sections, enhancing the NMFP by factors of ∼2.5-3.5 at the densities considered. The NMFP at the equilibrium density ρ0 are also calculated using the TDA and random phase approximation (RPA) using zero range Skyrme-like effective interactions with parameters chosen to reproduce the equation of state and spin-isospin susceptibilities of matter. Their results indicate that RPA corrections to correlated TDA may further increase the NMFP by ∼25% to 3-4 times those in a noninteracting FG. Finally, the sums and the energy weighted sums of the Fermi and Gamow-Teller responses obtained from the correlated ground state are compared with those of the 1 p-h response functions to extract the sum and mean energies of multi p-h contributions to the weak response. The relatively large mean energy of the multi p-h excitations suggests that they may not contribute significantly to low energy NMFP
Empirical observations on the unpredictable behavior of nuclear matter
International Nuclear Information System (INIS)
While many aspects of matter are unpredictable from basic principles, there are some that are susceptible to empirical descriptions which can be quite accurate and beautiful. One such example from the field of ''Nuclear Matter Under Extreme Conditions'' is the distribution of the number of particles produced, or alternatively, of the energy carried by these particles, in energetic collisions of atomic nuclei. The present work consists of a series of published scientific papers on measurements of the distribution of particles produced, or the energy carried by these particles, in collisions of various nuclei, spanning more than a decade of research. Due to the unpredictability of the theory, the work includes empirical studies of the regularity of the measured distributions from which significant knowledge is gained. The aesthetics of this subject derives from the physical beauty of the measured curves, the characteristic changes of shape with different species of nuclei, and the deep understanding obtained by the use of a simple and elegant mathematical function to describe the data
Study of the nuclear matter flow with the multidetector INDRA
International Nuclear Information System (INIS)
The work presented in this thesis relates to the study of the products which are not emitted by the statistical deexcitation of the projectile and target. The experiment on which this work is based on was performed at GANIL with the detector INDRA on two systems: 36 Ar + 58 Ni and 129 Xe + 119 Sn. A whole characterization (mass, composition, multiplicities and energy properties) of mid-rapidity emission has been done for the system 36 Ar + 58 Ni between 52 and 95 A.MeV. The amount of matter associated to this emission seems to be independent of the incident energy and directly linked with the centrality of the collision. The available energy per nucleon for the production of mid-rapidity products seems to be insensitive to the impact parameter. A systematic study of the nuclear matter in-plane flow has also been carried out. It has been established that the usual methods for reaction plane determination do not allow one to measure accurately the value of flow parameter at intermediate energies. Nevertheless, the inversion energy of the system 36 Ar + 58 Ni can be calculated for central collisions. This energy is independent of the nature of the products. Its value and the features of the mid-rapidity emission should allow one to extract in-medium nucleon-nucleon cross section by comparison with theoretical results. (author)
Sound waves and solitons in hot and dense nuclear matter
International Nuclear Information System (INIS)
Assuming that nuclear matter can be treated as a perfect fluid, we study the propagation of perturbations in the baryon density. The equation of state is derived from a relativistic mean field model, which is a variant of the non-linear Walecka model. The expansion of the Euler and continuity equations of relativistic hydrodynamics around equilibrium configurations leads to differential equations for the density perturbation. We solve them numerically for linear and spherical perturbations and follow the propagation of the initial pulses. For linear perturbations we find single soliton solutions and solutions with one or more solitons followed by 'radiation'. Depending on the equation of state a strong damping may occur. We consider also the evolution of perturbations in a medium without dispersive effects. In this case we observe the formation and breaking of shock waves. We study all these equations also for matter at finite temperature. Our results may be relevant for the analysis of RHIC data. They suggest that the shock waves formed in the quark gluon plasma phase may survive and propagate in the hadronic phase
Short-range correlations in quark and nuclear matter
Energy Technology Data Exchange (ETDEWEB)
Froemel, Frank
2007-06-15
In the first part of this thesis, the role of short-range correlations in quark matter is explored within the framework of the Nambu-Jona-Lasinio model. Starting from a next-to-leading order expansion in the inverse number of the quark colors, a fully self-consistent model constructed that employs the close relations between spectral functions and self-energies. In contrast to the usual quasiparticle approximations, this approach allows the investigation of the collisional broadening of the quark spectral function. Numerical calculations at various chemical potentials and zero temperature show that the short-range correlations do not only induce a finite width of the spectral function but also have some influence on the structure of the chiral phase transition. In the second part of this thesis, the temperature and density dependence of the nucleon spectral function in symmetric nuclear matter is investigated. The short-range correlations can be well described by a simple, self-consistent model on the one-particle-two-hole and two-particle-one-hole level (1p2h, 2p1h). The thermodynamically consistent description of the mean-field properties of the nucleons is ensured by incorporating a Skyrme-type potential. Calculations at temperatures and densities that can also be found in heavy-ion collisions or supernova explosions and the formation of neutron stars show that the correlations saturate at high temperatures and densities. (orig.)
Short-range correlations in quark and nuclear matter
International Nuclear Information System (INIS)
In the first part of this thesis, the role of short-range correlations in quark matter is explored within the framework of the Nambu-Jona-Lasinio model. Starting from a next-to-leading order expansion in the inverse number of the quark colors, a fully self-consistent model constructed that employs the close relations between spectral functions and self-energies. In contrast to the usual quasiparticle approximations, this approach allows the investigation of the collisional broadening of the quark spectral function. Numerical calculations at various chemical potentials and zero temperature show that the short-range correlations do not only induce a finite width of the spectral function but also have some influence on the structure of the chiral phase transition. In the second part of this thesis, the temperature and density dependence of the nucleon spectral function in symmetric nuclear matter is investigated. The short-range correlations can be well described by a simple, self-consistent model on the one-particle-two-hole and two-particle-one-hole level (1p2h, 2p1h). The thermodynamically consistent description of the mean-field properties of the nucleons is ensured by incorporating a Skyrme-type potential. Calculations at temperatures and densities that can also be found in heavy-ion collisions or supernova explosions and the formation of neutron stars show that the correlations saturate at high temperatures and densities. (orig.)
Conventional and Unconventional Pairing and Condensates in Dilute Nuclear Matter
Clark, John W.; Sedrakian, Armen; Stein, Martin; Huang, Xu-Guang; Khodel, Victor A.; Shaginyan, Vasily R.; Zverev, Mikhail V.
2016-03-01
This contribution will survey recent progress toward an understanding of diverse pairing phenomena in dilute nuclear matter at small and moderate isospin asymmetry, with results of potential relevance to supernova envelopes and proto-neutron stars. Application of ab initio many-body techniques has revealed a rich array of temperature-density phase diagrams, indexed by isospin asymmetry, which feature both conventional and unconventional superfluid phases. At low density there exist a homogeneous translationally invariant BCS phase, a homogeneous LOFF phase violating translational invariance, and an inhomogeneous translationally invariant phase-separated BCS phase. The transition from the BCS to the BEC phases is characterized in terms of the evolution, from weak to strong coupling, of the pairing gap, condensate wave function, and quasiparticle occupation numbers and spectra. Additionally, a schematic formal analysis of pairing in neutron matter at low to moderate densities is presented that establishes conditions for the emergence of both conventional and unconventional pairing solutions and encompasses the possibility of dineutron formation.
Interacting neutrino gas in a dense nuclear matter
International Nuclear Information System (INIS)
Full text: Relativistic mean field models have become an standard approach to describe nuclear matter at different density regimes. The model Lagrangian density where nucleons interact through the exchange of scalar, vector and isovector mesons has been widely used for that purpose. Here, our interest is turned to the behavior of the neutrinos inside the hadronic matter, composed by the nucleons and mesons. In particular, we want to investigate the effect of the weak force on the neutrino distribution in that system. So we add to the model Lagrangian the neutral Z boson and its interaction with nucleons and the neutrinos in the same spirit of the mean field approach, usually invoked to solve the model. We show that this procedure do not alter the hadronic distribution, as expected, but can have a large contribution to the description of the neutrino distribution and its mean free path. Effects of a nonzero temperature are also considered in our investigation. The inclusion of the charged weak bosons can be easily incorporated in our results, which, together with the addition of electrons with the constraint of neutral total charge, can make a possible realistic model to study neutron-rich stars. As a promising application, we intend to solve the relativistic TOV equation for the star, within and without the weak interaction in the model. (author)
Directory of Open Access Journals (Sweden)
Oller J.A.
2010-04-01
Full Text Available We review on a novel chiral power counting scheme for in-medium chiral perturbation theory with nucleons and pions as degrees of freedom. It allows for a systematic expansion taking into account local as well as pion-mediated inter-nucleon interactions. Based on this power counting, one can identify classes of nonperturbative diagrams that require a resummation. As a method for performing those resummations we review on the techniques of Unitary Chiral Pertubation Theory for nucleon-nucleon interactions. We then apply both power counting and non-perturbative methods to the example of calculating the pion self-energy in asymmetric nuclear matter up-to-and-including next-to-leading order. It is shown that the leading corrections involving in-medium nucleon-nucleon interactions cancel between each other at given chiral orders.
Iida, Kei
1997-01-01
Effects of energy dissipation on quantum nucleation of two-flavor quark matter in dense nuclear matter encountered in neutron star cores are examined at low temperatures. We find that low-energy excitations of nucleons and electrons reduce the nucleation rate exponentially via their collisions with the surface of a quark matter droplet.
Quantum Molecular Dynamics Approach to the Nuclear Matter Below the Saturation Density
Maruyama, Toshiki; Niita, Koji; Oyamatsu, Kazuhiro; MARUYAMA, Tomoyuki; Chiba, Satoshi; Iwamoto, Akira
1997-01-01
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.
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.)
Directional Search for Isospin-Violating Dark Matter with Nuclear Emulsion
Nagao, Keiko I
2012-01-01
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.
2011-06-02
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Saturation properties of nuclear matter in the presence of strong magnetic field
Rezaei, Z
2016-01-01
Different saturation properties of cold symmetric nuclear matter in the strong magnetic field have been considered. We have seen that for magnetic fields about $B> 3 \\times 10 ^ {17}\\ G$, {for both cases with and without nucleon anomalous magnetic moments}, the saturation density and saturation energy grow by increasing the magnetic field. It is indicated that the magnetic susceptibility of symmetric nuclear matter becomes negative showing the diamagnetic response especially at $B 3 \\times 10 ^ {17}\\ G$, {the softening of equation of state caused by Landau quantization is overwhelmed by stiffening due to the magnetization of nuclear matter.} We have shown that the effects of strong magnetic field on nuclear matter may affect the constraints on the equation of state of symmetric nuclear matter obtained applying the experimental observable.
The Bethe-Brueckner-Goldstone expansion in nuclear and neutron matter
International Nuclear Information System (INIS)
The microscopic theory of nuclear matter is developed within the Bethe-Brueckner-Goldstone expansion. Starting from different realistic nucleon-nucleon interactions, the equation of state of symmetric nuclear matter and pure neutron matter is calculated up to three-hole level of approximation. The expansion shows to be convergent up to densities relevant for neutron stars studies. Within the same scheme, the nucleon strength function is calculated in the kinematical region pertinent to deep inelastic electron scattering. (author)
Nuclear matter equation of state including few-nucleon correlations $(A\\leq 4)$
Röpke, G.
2014-01-01
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 saturatio...
International Nuclear Information System (INIS)
Non-destructive analytical methods based on interactions of nuclear radiation with matter are overviewed in this chapter of the textbook. The three major categories discussed are Moessbauer spectroscopy based on the nuclear resonance absorption of gamma radiation, positronium chemistry developed from the study of the interaction of positive beta radiation with matter, and the chemistry of muonium and muonic atoms connected with the interaction of mesons with matter. (R.P.)
Some recent progress on quark pairings in dense quark and nuclear matter
Pang, Jin-yi; Wang, Jin-cheng; Wang, Qun
2011-01-01
We give a brief overview on some recent progress in quark pairings in dense quark/nuclear matter mostly developed in the past five years. We focus on following aspects in particular: the BCS-BEC crossover in the CSC phase, the baryon formation and dissociation in dense quark/nuclear matter, the Ginzburg-Landau theory for three-flavor dense matter with $U_{A}$(1) anomaly, and the collective and Nambu-Goldstone modes for the spin-one CSC.
Sammarruca, Francesca
2016-01-01
We present predictions of the binding energy per nucleon and the neutron skin thickness in highly neutron-rich isotopes of Oxygen, Magnesium, and Aluminum. The calculations are carried out at and below the neutron drip line. The nuclear properties are obtained via an energy functional whose input is the equation of state of isospin-asymmetric in?finite matter. The latter is based on a microscopic derivation applying chiral few-nucleon forces. We highlight the impact of the equation of state at diff?erent orders of chiral effective fi?eld theory and discuss the role of three-neutron forces.
Neutron-Proton Mass Difference in Nuclear Matter and in Finite Nuclei and the Nolen-Schiffer Anomaly
Directory of Open Access Journals (Sweden)
Yakhshiev U.T.
2010-04-01
Full Text Available The neutron-proton mass diﬀerence in (isospin asymmetric nuclear matter and ﬁnite nuclei is studied in the framework of a medium-modiﬁed Skyrme model. The proposed eﬀective Lagrangian incorporates both the medium inﬂuence of the surrounding nuclear environment on the single nucleon properties and an explicit isospin-breaking eﬀect in the mesonic sector. Energy-dependent charged and neutral pion optical potentials in the s- and p-wave channels are included as well. The present approach predicts that the neutron-proton mass diﬀerence is mainly dictated by its strong part and that it markedly decreases in neutron matter. Furthermore, the possible interplay between the eﬀective nucleon mass in ﬁnite nuclei and the Nolen-Schiﬀer anomaly is discussed. In particular, we ﬁnd that a correct description of the properties of mirror nuclei leads to a stringent restriction of possible modiﬁcations of the nucleon’s eﬀective mass in nuclei.
International Nuclear Information System (INIS)
These Regulations prescribe, for the purposes of the definition of 'excepted matter' in the Nuclear Installations Act 1965, certain specified quantities and forms of nuclear matter, and supersede the Nuclear Installations (excepted Matter) Regulations 1965. They bring the definition of excepted matter in those Regulations into line with the decisions of 27 October 1977 of the OECD Nuclear Energy Agency's Steering Committee excluding certain kinds and quantities of nuclear substances from the scope of the Paris Convention on Third Party Liability in the Field of Nuclear Energy. Compared with the 1965 Regulations, the principal changes in relation to consignments are that activity limits and packing requirements now take account of the most recent IAEA Regulations. (NEA)
Relativistic nuclear collisions: search for new states of matter
International Nuclear Information System (INIS)
The group carries on a diverse program of research in relativistic heavy ion physics using projectiles supplied by the Bevalac. The unifying theme of this research program is the search for evidence for the possible formation of a new or anomalous states of nuclear matter in RHIC. Anomalous production of particles below threshold (for nucleon-nucleon collisions at equal energy/nucleon) provides evidence for collective effects that may lead to the production of Ne states of matter. In the past the authors have reported the observation of a surprisingly high rate of K- production in 2.1 GeV/nucleon 28Si + 28Si collisions. They have extended this investigation by measuring the momentum distribution of these subthreshold K-. Changes in the effective mass spectra of lepton pairs produced in RHIC, as a function of bombarding energy, may provide the clearest signature of the postulated phase transition to the quark-gluon plasma. The authors are collaborators in an effort to construct a new major facility at the Bevalac, the dilepton spectrometer, which will be used to study the production of e+e- pairs in RHIC. As a prelude to this effort, the authors have begun an experiment to measure the yield of single direct electrons at the Bevalac. In the first run of this experiment, data were taken for collisions of 2.1 GeV/nucleon p + Be. These data are still under analysis. Running time in the near future will be used to collect data on p + Be collisions at higher bombarding energies and on nucleus + nucleus collisions
Self-consistent tensor effects on nuclear matter system under relativistic Hartree-Fock approach
Jiang, Li Juan; Yang, Shen; Dong, Jian Min; Long, Wen Hui
2014-01-01
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 int...
Experimental aspects of quarkonia production and suppression in cold and hot nuclear matter
Frawley, A. D.
2015-01-01
When heavy Quarkonia are formed in collisions between between nuclei, their production cross section is modified relative to that in p+p collisions. The physical effects that cause this modification fall into two categories. Hot matter effects are due to the large energy density generated in the nuclear collision, which disrupts the formation of the quarkonium state. Cold nuclear matter effects are due to the fact that the quarkonium state is created in a nuclear target. I will review experim...
Bordbar, G. H.; Feridoonnezhad, R.; M. Taghizade
2015-01-01
In this work, we have done a completely microscopic calculation using a many-body variational method based on the cluster expansion of energy to compute the asymmetry energy of nuclear matter. In our calculations, we have employed the $AV_{18}$ nuclear potential. We have also investigated the temperature and density dependence of asymmetry energy. Our results show that the asymmetry energy of nuclear matter depends on both density and temperature. We have also studied the effects of different...
Functional renormalization group approach to neutron matter
Directory of Open Access Journals (Sweden)
Matthias Drews
2014-11-01
Full Text Available The chiral nucleon-meson model, previously applied to systems with equal number of neutrons and protons, is extended to asymmetric nuclear matter. Fluctuations are included in the framework of the functional renormalization group. The equation of state for pure neutron matter is studied and compared to recent advanced many-body calculations. The chiral condensate in neutron matter is computed as a function of baryon density. It is found that, once fluctuations are incorporated, the chiral restoration transition for pure neutron matter is shifted to high densities, much beyond three times the density of normal nuclear matter.
Study of Charmonium Production in Asymmetric Nuclear Collisions by the PHENIX Experiment at RHIC
,
2015-01-01
The measurement of quarkonia production in relativistic heavy ion collisions provides a powerful tool for studying the properties of the hot and dense matter created in these collisions. To be really useful, however, such measurements must cover a wide range of quarkonia states and colliding species. The PHENIX experiment at RHIC has successfully measured J/psi, psi-prime, chi_c and Upsilon production in different colliding systems at various energies. In this talk I will present recent results from the PHENIX collaboration on charmonium production in d+Au, Cu+Au and U+U collisions at 200 GeV/c.
On hypothesis of partial conservation of the axial-vector current in nuclear matter
International Nuclear Information System (INIS)
Expressions extending the vacuum relations of the axial-vector current conservation (PCAC) to the case of infinite nuclear matter are obtained. It is shown that the account of the S wave ?N interaction results in a modification of PCAC in the matter. The weak axial and the pion-nucleon vertices in the nuclear matter are obtained basing on the theory of finite Fermi systems. Contributions from transitions far from the Fermi surface are taken into account by means of the corresponding phenomenological constants. The pion decay amplitude in the matter is found, as well as its time component. Relation of the renormalization of the pion decay amplitude in the matter to the problem of the pion-condensate instability of the nuclear matter is discussed
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
Nuclear techniques and the particulate matter pollution in big harbours
International Nuclear Information System (INIS)
The impact of big harbours on the air quality is in important issue both from the environmental and the economical point of view. The harbour of Genoa is the largest in Italy and one of the major ports of the Mediterranean. We have determined the fraction of Particulate Matter (P M) concentration in town due to the heavy oil combustion of the diesel engines of the vessels in the harbour. This turned out to be 12% in P M10 and 25% in P M2.5 and P M1, with about 85% of the P M from this source concentrated in particles with aerodynamic diameter, D-ac < 1 μm. We could also point out a link between concentration peaks of the tracers of heavy oil combustion (V and Ni) and the ferryboats traffic. The key toot in this work was the coupling between particular sampling devices and some Ion Beam Analysis (IBA) techniques, in particular Particle Induced X-ray Emission (PIXE), which belong to the broader category of nuclear techniques in applied physics.
Zero sound and the renormalization scale in relativistic nuclear matter
International Nuclear Information System (INIS)
In this paper we report a study on the poles of the propagators of ? and ? mesons in the space-like region. In this region a zero sound can appear (a collective mode having a dispersion relation analogue to that obtained in sound propagation, but appearing at zero temperature) when the nucleon-nucleon interaction used is sufficiently repulsive. We have determined this zero sound by using a relativistic Hartree approximation, a model in which the vacuum fluctuations depend on a renormalization scale. Two renormalization schemes, corresponding to two different values of this scheme are physically acceptable. The first one corresponds to the relativistic Hartree approximation usually utilized, which minimizes the three and four body vacuum interactions. This leads to an incompressibility module which is two times higher than its experimental value. The second procedure minimizes the tree and four body interactions in the medium at saturation density, thus permitting the correct reproduction of the nuclear matter compressibility. We have shown that the zero sound which appears near the saturation density with the pure Hartree approximation occurs now at a density which is two times higher than the saturation density when the second choice of renormalization scale is done
The hadronization time of heavy quark in nuclear matter
Song, Taesoo
2016-01-01
We study the hadronization time of heavy quark in nuclear matter by using the coalescence model and the spatial diffusion constant of heavy quark from lattice Quantum Chromodynamic calculations, assuming that the main interaction of heavy quark at the critical temperature is hadronization. It is found that the hadronization time of heavy quark is about 3 fm/c for $2\\pi T_c D_s=6$, if a heavy quark is combined with the nearest light antiquark in coordinate space without any correlation between momentum of heavy quark and that of light antiquark which form a heavy meson. However, the hadronization time reduces to 0.6-1.2 fm/c for charm and 0.4-0.9 fm/c for bottom, depending on heavy meson radius, in the presence of momentum correlation. Considering the interspace between quarks and antiquarks at the critical temperature, it seems that the hadronization of heavy quark does not happen instantaneously but gradually for a considerable time, if started from the thermal distribution of quarks and antiquarks.
Multiplicity and cold-nuclear matter effects from Glauber-Gribov theory at LHC
Arsene, I. C.(Department of Physics, University of Oslo, Oslo, Norway); Bravina, L.; Kaidalov, A. B.; Tywoniuk, K.; Zabrodin, E.
2007-01-01
We present predictions for nuclear modification factor in proton-lead collisions at LHC energy 5.5 TeV from Glauber-Gribov theory of nuclear shadowing. We have also made predictions for baseline cold-matter nuclear effects in lead-lead collisions at the same energy.
Nucleon mean free path in nuclear matter based on nuclear Schwinger-Dyson formalism
International Nuclear Information System (INIS)
The mean free path of a nucleon moving through nuclear matter with kinetic energy larger than 100 MeV is formulated based on the bare vertex nuclear Schwinger-Dyson (BNSD) method in the Walecka model. The self-energy which is derived from diagrams of higher than fourth order includes the Feynman part of the propagator of an energetic nucleon and grows up rapidly with its kinetic energy increasing. To avoid too large a growth of these diagrams, meson propagators are modified by introducing some form factors to take into account an internal structure of hadrons. It is confirmed that a reasonable form factor is necessary to compare our numerical results of the mean free path with experimental data. (author)
Experimental aspects of quarkonia production and suppression in cold and hot nuclear matter
Frawley, A D
2015-01-01
When heavy Quarkonia are formed in collisions between between nuclei, their production cross section is modified relative to that in p+p collisions. The physical effects that cause this modification fall into two categories. Hot matter effects are due to the large energy density generated in the nuclear collision, which disrupts the formation of the quarkonium state. Cold nuclear matter effects are due to the fact that the quarkonium state is created in a nuclear target. I will review experimental aspects of quarkonia production due to both hot and cold matter effects.
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, σ(E), of the isoscalar giant monopole resonance (ISGMR) and the isoscalar giant dipole resonance (ISGDR), by inelastic α-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 σ(E), obtained within the folding-model distorted-wave-Born approximation with transition densities pt(r ) obtained from HF-RPA calculations. We provide an explanation for the discrepancy between theory and experiment concerning S(E) of the ISGDR. (3) The apparent discrepancy of about 20 % in the value of Knm as predicted by the relativistic and the non-relativistic models. Our investigation suggests that this discrepancy is mainly due to the different values of the symmetry energy coefficient employed in the relativistic and the non-relativistic models
Constraints on the equation of state of cold dense matter from nuclear physics and astrophysics
Directory of Open Access Journals (Sweden)
Fantina A. F.
2014-03-01
Full Text Available The Brussels-Montreal equations of state of cold dense nuclear matter that have been recently developed are tested against various constraints coming from both nuclear physics and astrophysics. The nuclear physics constraints include the analysis of nuclear flow and kaon production in heavy-ion collision experiments, as well as recent microscopic many-body calculations of infinite homogeneous neutron matter. Astrophysical observations, especially recent neutron-star mass measurements, provide valuable constraints on the high-density part of the equation of state that is not accessible in laboratory experiments.
Jung, Ju-Hyun; Yakhshiev, Ulugbek; Kim, Hyun-Chul
2016-03-01
We investigate the medium modification of the generalized vector form factors of the nucleon, which include the electromagnetic and energy-momentum tensor form factors, based on an in-medium modified π -ρ -ω soliton model. We find that the vector form factors of the nucleon in nuclear matter fall off faster than those in free space, which implies that the charge radii of the nucleon become larger in nuclear medium than in free space. We also compute the corresponding transverse charge densities of the nucleon in nuclear matter, which clearly reveal the increasing of the nucleon size in nuclear medium.
Jung, Ju-Hyun; Kim, Hyun-Chul
2015-01-01
We investigate the medium modification of the generalized vector form factors of the nucleon, which include the electromagnetic and energy-momentum tensor form factors, based on an in-medium modified $\\pi$-$\\rho$-$\\omega$ soliton model. We find that the vector form factors of the nucleon in nuclear matter fall off faster than those in free space, which implies that the charge radii of the nucleon become larger in nuclear medium than in free space. We also compute the corresponding transverse charge densities of the nucleon in nuclear matter, which clearly reveal the increasing of the nucleon size in nuclear medium.
Influence of spin polarizability on liquid gas phase transition in the nuclear matter
Rezaei, Z; Bordbar, G H
2015-01-01
In this paper, we investigate the liquid gas phase transition for the spin polarized nuclear matter. Applying the lowest order constrained variational (LOCV) method, and using two microscopic potentials, $AV_{18}$ and $UV_{14}$+TNI, we calculate the free energy, equation of state, order parameter, entropy, heat capacity and compressibility to derive the critical properties of spin polarized nuclear matter. Our results indicate that for the spin polarized nuclear matter, the second order phase transition takes place at lower temperatures with respect to the unpolarized one. It is also shown that the critical temperature of our spin polarized nuclear matter with a specific value of spin polarization parameter is in good agreement with the experimental result.
On the phase stability of hot nuclear matter and the applicability of detailed balance equations
International Nuclear Information System (INIS)
In a quantum statistical approach which takes into account the formation of bound states some properties of hot nuclear matter are studied. Possible consequences for the application of thermal models in relativistic heavy-ion reactions are discussed. (orig.)
Interplay between collision dynamics and nuclear matter properties from microscopic viewpoint
Directory of Open Access Journals (Sweden)
Ono Akira
2012-07-01
Full Text Available Nuclear matter properties have been explored through heavy-ion collisions. Studies with microscopic dynamical models, such as antisymmetrized molecular dynamics, are reviewed putting some emphasis on fragmentation and clusterization.
Nuclear matter equation of state including few-nucleon correlations $(A\\leq 4)$
Rpke, G
2014-01-01
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.
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. Rssler, 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
Energy Technology Data Exchange (ETDEWEB)
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
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 (α{sub 1}-process), the second reorienting isotropically (α{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 α{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 α{sub 2}-process. As demonstrated by {sup 2}H NMR, the PS matrix reflects the faster α{sub 2}-process of TPP by performing a spatially highly hindered motion on the same timescale.
Fractal structure of near-threshold quarkonium production off cold nuclear matter
Bhaduri, Partha Pratim
2013-01-01
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.
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.)
Khan, E.; Margueron, J.; G. Colo; Hagino, K.; H. Sagawa
2010-01-01
The role of superfluidity in the incompressibility and in the symmetry energy is studied in nuclear matter and finite nuclei. Several pairing interactions are used: surface, mixed and isovector dependent. Pairing has a small effect on the nuclear matter incompressibility at saturation density, but the effects are significant at lower densities. The pairing effect on the centroid energy of the isoscalar Giant Monopole Resonance (GMR) is also evaluated for Pb and Sn isotopes by using a microsco...
Neutrino propagation in Neutron Matter and the Nuclear Equation of State
Margueron, J.; Navarro, J.; N. Van Giai(Institut de Physique Nucleaire, Orsay, France); Jiang, W.
2001-01-01
We study the propagation of neutrinos inside dense matter under the conditions prevailing in a proto-neutron star. Equations of state obtained with different nuclear effective interactions (Skyrme type and Gogny type) are first discussed. It is found that for many interactions, spin and/or isospin instabilities occur at densities larger than the saturation density of nuclear matter. From this study we select two representative interactions, SLy230b and D1P. We calculate the response functions...
Do Skyrme forces that fit nuclear matter work well in finite nuclei?
Stevenson, P D; Stone, J R; Dutra, M
2012-01-01
A shortlist of Skyrme force parameterizations, recently found to have passed a series of constraints relating to nuclear matter properties is analyzed for their ability to reproduce data in finite nuclei. We analyse binding energies, isotope shifts and fission barriers. We find that the subset of forces have no common ability to reproduce (or otherwise) properties of finite nuclei, despite passing the extensive range of nuclear matter constraints.
Kahlau, R.; Bock, D.; Schmidtke, B.; Rössler, E. A.
2014-01-01
Dielectric spectroscopy as well as 2H and 31P nuclear magnetic resonance spectroscopy (NMR) are applied to probe the component dynamics of the binary glass former tripropyl phosphate (TPP)/polystyrene (PS/PS-d3) in the full concentration (cTPP) range. In addition, depolarized light scattering and differential scanning calorimetry experiments are performed. Two glass transition temperatures are found: Tg1(cTPP) reflects PS dynamics and shows a monotonic plasticizer effect, while the lower Tg2(cTPP) exhibits a maximum and is attributed to (faster) TPP dynamics, occurring in a slowly moving or immobilized PS matrix. Dielectric spectroscopy probing solely TPP identifies two different time scales, which are attributed to two sub-ensembles. One of them, again, shows fast TPP dynamics (α2-process), the other (α1-process) displays time constants identical with those of the slow PS matrix. Upon heating the α1-fraction of TPP decreases until above some temperature Tc only a single α2-population exists. Inversely, below Tc a fraction of the TPP molecules is trapped by the PS matrix. At low cTPP the α2-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 α2-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 τ2(T), as well as FTS are recovered, known as typical of the glass transition in neat systems.
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 (α2-process), the other (α1-process) displays time constants identical with those of the slow PS matrix. Upon heating the α1-fraction of TPP decreases until above some temperature Tc only a single α2-population exists. Inversely, below Tc a fraction of the TPP molecules is trapped by the PS matrix. At low cTPP the α2-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 α2-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 τ2(T), as well as FTS are recovered, known as typical of the glass transition in neat systems
Energy Technology Data Exchange (ETDEWEB)
Kahlau, R.; Bock, D.; Schmidtke, B.; Rössler, E. A., E-mail: ernst.roessler@uni-bayreuth.de [Experimentalphysik II, Universität Bayreuth, 95440 Bayreuth (Germany)
2014-01-28
Dielectric spectroscopy as well as {sup 2}H and {sup 31}P nuclear magnetic resonance spectroscopy (NMR) are applied to probe the component dynamics of the binary glass former tripropyl phosphate (TPP)/polystyrene (PS/PS-d{sub 3}) in the full concentration (c{sub TPP}) range. In addition, depolarized light scattering and differential scanning calorimetry experiments are performed. Two glass transition temperatures are found: T{sub g1}(c{sub TPP}) reflects PS dynamics and shows a monotonic plasticizer effect, while the lower T{sub g2}(c{sub TPP}) exhibits a maximum and is attributed to (faster) TPP dynamics, occurring in a slowly moving or immobilized PS matrix. Dielectric spectroscopy probing solely TPP identifies two different time scales, which are attributed to two sub-ensembles. One of them, again, shows fast TPP dynamics (α{sub 2}-process), the other (α{sub 1}-process) displays time constants identical with those of the slow PS matrix. Upon heating the α{sub 1}-fraction of TPP decreases until above some temperature T{sub c} only a single α{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 α{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 α{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 τ{sub 2}(T), as well as FTS are recovered, known as typical of the glass transition in neat systems.
Equation of state for nuclear matter in core-collapse supernovae by the variational method
International Nuclear Information System (INIS)
We construct a new nuclear equation of state (EOS) for core-collapse supernova (SN) simulations using the variational many-body theory. For uniform nuclear matter, the EOS is constructed with the cluster variational method starting from the realistic nuclear Hamiltonian composed of the Argonne v18 two-body potential and the Urbana IX three-body potential. The masses and radii of neutron stars calculated with the obtained EOS at zero temperature are consistent with recent observational data. For non-uniform nuclear matter, we construct the EOS in the Thomas-Fermi approximation. In this approximation, we assume a functional form of the density distributions of protons, neutrons, and alpha-particles, and minimize the free energy density in a Wigner-Seitz cell with respect to the parameters included in the assumed density distribution functions. The phase diagram of hot nuclear matter at a typical temperature is reasonable as compared with that of the Shen EOS
Gupta, V K; Singh, S; Anand, J D; Gupta, Asha
2002-01-01
We have studied phase transition from hadron matter to quark matter in the presence of high magnetic fields incorporating the trapped electron neutrinos at finite temperatures. We have used the density dependent quark mass (DDQM) model for the quark phase while the hadron phase is treated in the frame-work of relativistic mean field theory. It is seen that the nuclear energy at phase transition decreases with both magnetic field and temperature. A brief discussion of the effect of magnetic field in supernova explosions and proto-neutron star evolution is given.
Takacs, Maria; Petoukhov, Maxim V.; Atkinson, R. Andrew; Roblin, Pierre; Ogi, Franois-Xavier; Demeler, Borries; Potier, Noelle; Chebaro, Yassmine; Dejaegere, Annick; Svergun, Dmitri I.; Moras, Dino; Billas, Isabelle M. L.
2013-01-01
Background PGC-1? is a crucial regulator of cellular metabolism and energy homeostasis that functionally acts together with the estrogen-related receptors (ERR? and ERR?) in the regulation of mitochondrial and metabolic gene networks. Dimerization of the ERRs is a pre-requisite for interactions with PGC-1? and other coactivators, eventually leading to transactivation. It was suggested recently (Devarakonda et al) that PGC-1? binds in a strikingly different manner to ERR? ligand-binding domains (LBDs) compared to its mode of binding to ERR? and other nuclear receptors (NRs), where it interacts directly with the two ERR? homodimer subunits. Methods/Principal Findings Here, we show that PGC-1? receptor interacting domain (RID) binds in an almost identical manner to ERR? and ERR? homodimers. Microscale thermophoresis demonstrated that the interactions between PGC-1? RID and ERR LBDs involve a single receptor subunit through high-affinity, ERR-specific L3 and low-affinity L2 interactions. NMR studies further defined the limits of PGC-1? RID that interacts with ERRs. Consistent with these findings, the solution structures of PGC-1?/ERR? LBDs and PGC-1?/ERR? LBDs complexes share an identical architecture with an asymmetric binding of PGC-1? to homodimeric ERR. Conclusions/Significance These studies provide the molecular determinants for the specificity of interactions between PGC-1? and the ERRs, whereby negative cooperativity prevails in the binding of the coactivators to these receptors. Our work indicates that allosteric regulation may be a general mechanism controlling the binding of the coactivators to homodimers. PMID:23874451
Some Recent Progress on Quark Pairings in Dense Quark and Nuclear Matter
International Nuclear Information System (INIS)
In this review article we give a brief overview on some recent progress in quark pairings in dense quark/nuclear matter mostly developed in the past five years. We focus on following aspects in particular: the BCS-BEC crossover in the CSC phase, the baryon formation and dissociation in dense quark/nuclear matter, the Ginzburg-Landau theory for three-flavor dense matter with UA(1) anomaly, and the collective and Nambu-Goldstone modes for the spin-one CSC. (physics of elementary particles and fields)
Nuclear matter saturation point and symmetry energy with modern nucleon-nucleon potentials
International Nuclear Information System (INIS)
We determine the saturation properties of nuclear matter within the Brueckner-Hartree-Fock approach based on a large set of modern nucleon-nucleon potentials and confirm the validity of the Coester band. The improvement of the saturation point when including nuclear three-body forces is pointed out and comparison with the Dirac-Brueckner-Hartree-Fock results is made
Three quark clusters in hot and dense nuclear matter
International Nuclear Information System (INIS)
We present a relativistic in-medium three-body equation to study correlations in hot and dense quark matter. The equation is solved for a zero-range force for parameters close to the phase transition of QCD. (orig.)
Three Quark Clusters in Hot and Dense Nuclear Matter
Beyer, M.; Mattiello, S.; Frederico, T; H. J. Weber
2002-01-01
We present a relativistic in-medium three-body equation to study correlations in hot and dense quark matter. The equation is solved for a zero-range force for parameters close to the phase transition of QCD.
A new explanation to the cold nuclear matter effects in heavy ion collisions
LIU, ZHI-FENG
2014-01-01
The J/Psi cross section ratios of p-A/p-p under different collision energy is calculated with cold nuclear matter effects redefined in this paper. The advantage of these new definitions is that all cold nuclear matter effects have clear physical origins.The radios are compared with the corresponding experiment data and that calculated with classic nuclear effects. The ratios calculated with new definitions can reproduce almost all existing J/Psi measurements in p-A collisions more accuratly t...
Constraining the nuclear matter equation of state around twice saturation density
Le Fvre, A.; Leifels, Y.; Reisdorf, W.; Aichelin, J.; Hartnack, Ch.
2016-01-01
Using FOPI data on elliptic flow in Au + Au collisions between 0.4 and 1.5 AGeV 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 3?0.
Effective interaction: From nuclear reactions to neutron stars
Indian Academy of Sciences (India)
D N Basu
2014-05-01
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 behaviour of symmetric and asymmetric nuclear matter satisfies the constraints from the observed flow data of heavy-ion collisions. The neutron star properties studied using -equilibrated neutron star matter obtained from this effective interaction reconcile with the recent observations of the massive compact stars.
International Nuclear Information System (INIS)
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 Esym (ρ) and its density slope L(ρ) at an arbitrary density ρ 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 Esym (ρ) and L(ρ) are analyzed in detail at different densities. It is shown that the behavior of Esym is mainly determined by the first-order symmetry potential Usym,1(ρ, k) of the single-nucleon potential. The density slope L(ρ) depends not only on the first-order symmetry potential Usym,1(ρ, k) but also on the second-order one Usym,2(ρ, k). Both the Usym,1(ρ, k) and Usym,2(ρ, k) at normal density ρ 0 are constrained by the isospin- and momentum-dependent nucleon optical potential extracted from the available nucleon-nucleus scattering data. The Usym,2(ρ, k) especially at high density and momentum affects significantly the L(ρ), but it is theoretically poorly understood and currently there is almost no experimental constraints known. (orig.)
A beyond-mean-field example with zerorange effective interactions in infinite nuclear matter
Directory of Open Access Journals (Sweden)
Col G.
2012-12-01
Full Text Available Zerorange effective interactions are commonly used in nuclear physics to describe a many-body system in the mean-field framework. If they are employed in beyond-mean-field models, an artificial ultraviolet divergence is generated by the zero-range of the interaction. We analyze this problem in symmetric nuclear matter with the t0 t3 Skyrme model. In this case, the second-order energy correction diverges linearly with the momentum cutoff ?. After that, we extend the work to the case of nuclear matter with the full Skyrme interaction. A strong divergence (? ?5 related to the velocity-dependent terms of the interaction is obtained. Moreover, a global fit can be simultaneously performed for both symmetric and nuclear matter with different neutron-to-proton ratios. These results pave the way for applications to finite nuclei in the framework of beyond mean-field theories.
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.)
Effective meson masses in nuclear matter based on a cutoff field theory
International Nuclear Information System (INIS)
Effective masses of σ, ω, π, and ρ mesons in nuclear matter are calculated based on a cutoff field theory. Instead of the traditional density-Feynman representation, we adopt the particle-hole-antiparticle representation for nuclear propagators so that unphysical components are not included in the meson self-energies. For an estimation of the contribution from the divergent particle-antiparticle excitations, i.e., vacuum polarization in nuclear matter, the idea of the renormalization group method is adopted. In this cutoff field theory, all the counterterms are finite and calculated numerically. It is shown that the predicted meson masses converge even if the cutoff Λ is changed as long as Λ is sufficiently large and that the prescription works well also for so-called nonrenormalized mesons such as π and ρ. According to this method, it is concluded that meson masses in nuclear matter have a weak dependence on the baryon density. copyright 1997 The American Physical Society
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.)
International Nuclear Information System (INIS)
The method of correlated basis functions is studied and applied to the Fermi systems: liquid 3He, nuclear matter and neutron matter. The reduced cluster integrals xsub(ijkl...) and so the subnormalization integrals Isub(ijkl...) are generalized to coinciding quantum numbers out of the set [i, j, k, l,...]. This generalization has an important consequence for the radial distribution function g(r) (and then for the liquid structure function); g(r) has no contributions of the order 0(A-1). For 3He the state-independent two-body correlation function f(r) is calculated from the Euler-Lagrange equation (in the limit of r → 0) for the unrenormalized two-body energy functional. For nuclear matter and neutron matter we adopt the three-parameter correlation function of Baeckman et al. Then the energy expectation values are calculated by including up to the three-body terms in the un-renormalized and renormalized version of the correlated basis functions method. (orig.)
Systematic analysis of the incoming quark energy loss in cold nuclear matter
Song, Li-hua; Duan, Chun-Gui; Liu, Na
2012-01-01
The investigation into the fast parton energy loss in cold nuclear matter is crucial for a good understanding of the parton propagation in hot-dense medium. By means of four typical sets of nuclear parton distributions and three parametrizations of quark energy loss, the parameter values in quark energy loss expressions are determined from a leading order statistical analysis of the existing experimental data on nuclear Drell-Yan differential cross section ratio as a function of the quark mom...
Clusterized nuclear matter in the (proto-)neutron star crust and the symmetry energy
Energy Technology Data Exchange (ETDEWEB)
Raduta, A.R. [IFIN-HH, Bucharest-Magurele (Romania); Aymard, F.; Gulminelli, F. [CNRS, UMR6534, LPC, Caen (France); ENSICAEN, UMR6534, LPC, Caen (France)
2014-02-15
Though generally agreed that the symmetry energy plays a dramatic role in determining the structure of neutron stars and the evolution of core-collapsing supernovae, little is known in what concerns its value away from normal nuclear matter density and, even more important, the correct definition of this quantity in the case of unhomogeneous matter. Indeed, nuclear matter traditionally addressed by mean-field models is uniform while clusters are known to exist in the dilute baryonic matter which constitutes the main component of compact objects outer shells. In the present work we investigate the meaning of symmetry energy in the case of clusterized systems and the sensitivity of the proto-neutron star composition and equation of state to the effective interaction. To this aim an improved Nuclear Statistical Equilibrium (NSE) model is developed, where the same effective interaction is consistently used to determine the clusters and unbound particles energy functionals in the self-consistent mean-field approximation. In the same framework, in-medium modifications to the cluster energies due to the presence of the nuclear gas are evaluated. We show that the excluded volume effect does not exhaust the in-medium effects and an extra isospin and density-dependent energy shift has to be considered to consistently determine the composition of subsaturation stellar matter. The symmetry energy of diluted matter is seen to depend on the isovector properties of the effective interaction, but its behavior with density and its quantitative value are strongly modified by clusterization. (orig.)