Incompressibility of asymmetric nuclear matter
Chen, Lie-Wen; Cai, Bao-Jun; Shen, Chun; Ko, Che Ming; Xu, Jun; Li, Bao-An(Department of Physics and Astronomy, Texas A&M University-Commerce, Commerce, TX, 75429-3011, USA)
2009-01-01
The incompressibility $K_sat(\\delta)$ of isospin asymmetric nuclear matter at its saturation density. Our results show that in the expansion of $K_sat(\\delta)$ in powers of isospin asymmetry $\\delta$, i.e., $K_sat(\\delta )$=K_{0}+K_{sat,2}\\delta^{2}+K_{sat,4}\\delta^{4}+O(\\delta^{6})$, the magnitude of the 4th-order K_{sat,4} parameter is generally small. The 2nd-order K_{sat,2} parameter thus essentially characterizes the isospin dependence of the incompressibility of asymmetric nuclear matte...
Incompressibility of asymmetric nuclear matter
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)
Hot and flowing, asymmetric nuclear matter
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)
Phase transitions in warm, asymmetric nuclear matter
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)
Equation of state and phase transitions in asymmetric nuclear matter
Kolomietz, V. M.; Sanzhur, A. I.; Shlomo, S.; Firin, S. A.
2001-01-01
The structure of the 3-dimension pressure-temperature-asymmetry surface of equilibrium of the asymmetric nuclear matter is studied within the thermal Thomas-Fermi approximation. Special attention is paid to the difference of the asymmetry parameter between the boiling sheet and that of the condensation sheet of the surface of equilibrium. We derive the condition of existence of the regime of retrograde condensation at the boiling of the asymmetric nuclear matter. We have performed calculation...
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...
Equation of state and phase transitions in asymmetric nuclear matter
Kolomietz, V M; Shlomo, S; Firin, S A
2001-01-01
The structure of the 3-dimension pressure-temperature-asymmetry surface of equilibrium of the asymmetric nuclear matter is studied within the thermal Thomas-Fermi approximation. Special attention is paid to the difference of the asymmetry parameter between the boiling sheet and that of the condensation sheet of the surface of equilibrium. We derive the condition of existence of the regime of retrograde condensation at the boiling of the asymmetric nuclear matter. We have performed calculations of the caloric curves in the case of isobaric heating. We have shown the presence of the plateau region in caloric curves at the isobaric heating of the asymmetric nuclear matter. The shape of the caloric curve depends on the pressure and is sensitive to the value of the asymmetry parameter. We point out that the experimental value of the plateau temperature T \\approx 7 MeV corresponds to the pressure P = 0.01 MeV/fm^3 at the isobaric boiling.
Equation of state and phase transitions in asymmetric nuclear matter
The structure of the three-dimension pressure-temperature-asymmetry surface of equilibrium of the asymmetric nuclear matter is studied within the thermal Thomas-Fermi approximation. Special attention is paid to the difference of the asymmetry parameter between the boiling sheet and that of the condensation sheet of the surface of equilibrium. We derive the condition of existence of the regime of retrograde condensation at the boiling of the asymmetric nuclear matter. We have performed calculations of the caloric curves in the case of isobaric heating. We have shown the presence of the plateau region in caloric curves at the isobaric heating of the asymmetric nuclear matter. The shape of the caloric curve depends on the pressure and is sensitive to the value of the asymmetry parameter. We point out that the experimental value of the plateau temperature T∼7 MeV corresponds to the pressure P=10-2 MeV/fm3 at the isobaric boiling
Correlations and spectral functions in asymmetric nuclear matter
The self-energy of nucleons in asymmetric nuclear matter is evaluated employing different realistic models for the nucleon-nucleon interaction. Starting from the Brueckner-Hartree-Fock approximation without the usual angle average in the two-nucleon propagator the effects of the hole-hole contributions are investigated within the self-consistent Green's function approach. Special attention is paid to the isospin dependence of correlations, which can be deduced from the spectral functions of nucleons in asymmetric matter. The strong components of the proton-neutron interaction lead in neutron-rich matter to a larger depletion for the occupation probability of proton states below the Fermi momentum
Application of density dependent parametrization models to asymmetric nuclear matter
Density dependent parametrization models of the nucleon-meson effective couplings, including the isovector scalar δ-field, are applied to asymmetric nuclear matter. The nuclear equation of state and the neutron star properties are studied in an effective Lagrangian density approach, using the relativistic mean field hadron theory. It is known that the introduction of a δ-meson in the constant coupling scheme leads to an increase of the symmetry energy at high density and so to larger neutron star masses, in a pure nucleon-lepton scheme. We use here a more microscopic density dependent model of the nucleon-meson couplings to study the properties of neutron star matter and to reexamine the δ-field effects in asymmetric nuclear matter. Our calculations show that, due to the increase of the effective δ coupling at high density, with density dependent couplings the neutron star masses in fact can be even reduced
Isovector Scalar Field Effects in Asymmetric Nuclear Matter
WANG Zhi-Xia; LIU Bo; ZHANG Xi-He; SHEN Cai-Wan; SHEN Ke; M. Di Toro; ZHAO En-Guang
2008-01-01
Density-dependent parametrization models of the nucleon-meson coupling constants, including the isovector scalar δ-field, are applied to asymmetric nuclear matter. The nuclear equation of state (EOS) and the neutron star properties are studied in a relativistic Lagrangian density, using the relativistic mean field (RMF) hadron theory. It is known that the 5-field in the constant coupling scheme leads to a larger repulsion in dense neutron-rich matter and to a definite splitting of proton and neutron effective masses, finally influences the stability of the neutron stars. We use density-dependent models of the nucleon-meson couplings to study the properties of neutron star matter and to reexamine the δ-field effects in asymmetric nuclear matter. Our calculation shows that the stability conditions of the neutron star matter can be improved in presence of the 5-meson in the density-dependent models of the coupling constants. The EOS of nuclear matter strongly depends on the density dependence of the interactions.
Neutron-proton mass difference in isospin asymmetric nuclear matter
Meißner, Ulf-G; Wirzba, A; Yakhshiev, U T
2007-01-01
Isospin-breaking effects in the baryonic sector are studied in the framework of a medium-modified Skyrme model. The neutron-proton mass difference in infinite, asymmetric nuclear matter is discussed. In order to describe the influence of the nuclear environment on the skyrmions, we include energy-dependent charged and neutral pion optical potentials in the s- and p-wave channels. The present approach predicts that the neutron-proton mass difference is mainly dictated by its strong part and that it strongly decreases in neutron matter.
Asymmetric nuclear matter : A variational approach with reid93 interaction
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
Short Range Correlations and Spectral Functions in Asymmetric Nuclear Matter
Konrad, P; Lenske, H.; Mosel, U.
2005-01-01
Dynamical correlations in asymmetric infinite nuclear matter are investigates in a transport theoretical approach. Self-energies due to short range correlations and their influence on the nucleon spectral functions are described in an approach accounting for a realistic treatment of mean-field dynamics and a self-consistently derived quasi-particle interaction. Landau-Migdal theory is used to derived the short range interaction from a phenomenological Skyrme energy density functional. The spe...
Pairing effects on spinodal decomposition of asymmetric nuclear matter
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.
DBHF Method for Asymmetric Nuclear Matter and Finite Nuclei
2001-01-01
The asymmetric nuclear matter is investigated in the DBHF approach with a new decomposition of the Dirac structure of nucleon self-energy. The coupling constants of σ, ω, δ and ρ mesons are deduced by reproducing the self-energy of DBHF calculation at every density and every asymmetry parameter in the RMF approximation. With these couplings the properties of finite nuclei are investigated. It is found that both scalar and vector potentials of neutron in the neutron rich nuclear matter become stronger although the isospin dependence of them is weaker. A significant difference in comparison with those, that the nucleon self-energy is deduced from the single particle energy, is observed. The nuclear binding energy as a function of the asymmetry parameter fulfills the empirical
Collective modes in hot asymmetric nuclear matter at variable densities
A nearly exact expression for the response function of hot asymmetric nuclear matter is derived for Skyrme type effective interactions and the resulting strength distribution is analyzed for the four channels of the particle-hole interaction. Several proton-neutron asymmetries are considered as well as different total densities. In the isovector channel the strength presents a very collective behaviour (zero sound type) which becomes still more collective with increasing asymmetry. For higher nuclear densities it may be collective or unstable depending on the effective interaction. This is also the behaviour for the spin-isospin channel. The other channels may have the collectivity increased for a highly asymmetric nuclear matter at higher densities. In the spin channel zero sound modes are found for higher enough p-n asymmetries and/or densities higher than the saturation density. The static limit of the polarizabilities are considered yielding the symmetry energy coefficients for isovector, spin and spin-isospin channels. The dependence of the polarizabilities on p-n asymmetry is analyzed, in particular in the isovector channel which is of interest, for example, for the supernovae mechanism
Higher order bulk characteristic parameters of asymmetric nuclear matter
无
2011-01-01
The bulk parameters characterizing the energy of symmetric nuclear matter and the symmetry energy defined at normal nuclear density ρ0 provide important information on the equation of state (EOS) of isospin asymmetric nuclear matter. While significant progress has been made in determining some lower order bulk characteristic parameters, such as the energy E0(ρ0) and incompress ibility K0 of symmetric nuclear matter as well as the symmetry energy Esym(ρ0) and its slope parameter L, yet the higher order bulk characteristic parameters are still poorly known. Here, we analyze the correlations between the lower and higher order bulk char acteristic parameters within the framework of Skyrme Hartree-Fock energy density functional and then estimate the values of some higher order bulk characteristic parameters. In particular, we obtain J0 = (-355±95) MeV and I0 = (1473±680) MeV for the third order and fourth-order derivative parameters of symmetric nuclear matter at ρ0 and Ksym = (-100 ± 165) MeV, Jsym = (224 ± 385) MeV, Isym = (-1309 ± 2025) MeV for the curvature parameter, third-order and fourth-order derivative parameters of the symmetry energy at ρ0, using the empirical constraints on E0(ρ0), K0, Esym(ρ0), L, and the isoscalar and isovector nucleon effective masses. Furthermore, our results indicate that the three parameters E0(ρ0), K0, and J0 can reasonably characterize the EOS of symmetric nuclear matter up to 2ρ0 while the symmetry energy up to 2ρ0 can be well described by Esym(ρ0), L, and Ksym.
Effects of Microscopic Three-body Forces in Asymmetric Nuclear Matter
无
2001-01-01
The efiects of microscopic three-body forces on the equatioil of state(EOS)and the single particle properties of isospin asymmetric nuclear matter have been studied within Brueckner-Hartree-Fock framework~[1]The microscopic three-body force model constructed from meson exchange current approach in Ref.~[2] has been extended to isospin asymmetric nuclear matter
On growth of spinodal instabilities in nuclear matter-II:asymmetric matter
Acar, F; Yilmaz, O; Gokalp, A
2015-01-01
As an extension of our previous work, the growth of density fluctuations in the spinodal region of charge asymmetric nuclear matter is investigated in the basis of the stochastic mean-field approach in the non-relativistic framework. A complete treatment of density correlation functions are presented by including collective modes and non-collective modes as well.
AMD study of the EOS of asymmetric nuclear matter in nuclear collisions
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)
A New Decomposition Approach of Dirac Brueckner Hartree-Fock G Matrix for Asymmetric Nuclear Matter
刘玲; 马中玉
2002-01-01
Asymmetric nuclear matter is investigated by the Dirac Brueckner Hartree-Fock (DBHF) approach with a new decomposition of the Dirac structure of nucleon self-energy from the G matrix. It is found that the isospin dependence of the scalar and vector potentials is relatively weak, although both potentials for neutron (proton)become deep (shallow) in the neutron-rich nuclear matter. The results in asymmetric nuclear matter are rather different from those obtained by a simple method, where the nucleon self-energy is deduced from the single-particle energy. The nuclear binding energy as a function of the asymmetry parameter fulfils the empirical parabolic law up to very extreme isospin asymmetric nuclear matter in the DBHF approach. The behaviour of the density dependence of the asymmetry energy is different from that obtained by non-relativistic approaches, although both give similar asymmetry energy at the nuclear saturation density.
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.
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.
Symmetry energy parameters in pion-dressed asymmetric nuclear matter
We have carried out the calculations of these three bulk properties in our model of pion-pair dressed nuclear matter and have compared the results with those obtained from standard models using interactions like the NL3, Quark-Meson Coupling (QMC) and Typel and Wolter (TW). We observe that the results produced by our model compare very well with these models although the degree of complexity of our model is much lower
Nucleon mean free path in asymmetric nuclear matter at finite temperature
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...
Higher-order effects on the incompressibility of isospin asymmetric nuclear matter
Chen, Lie-Wen; Cai, Bao-Jun; Ko, Che Ming; Li, Bao-An(Department of Physics and Astronomy, Texas A&M University-Commerce, Commerce, TX, 75429-3011, USA); Shen, Chun; Xu, Jun
2009-01-01
Analytical expressions for the saturation density as well as the binding energy and incompressibility at the saturation density of asymmetric nuclear matter are given exactly up to 4th-order in the isospin asymmetry delta =(rho_n - rho_p)/rho using 11 characteristic parameters defined at the normal nuclear density rho_0. Using an isospin- and momentum-dependent modified Gogny (MDI) interaction and the SHF approach with 63 popular Skyrme interactions, we have systematically studied the isospin...
Properties of dense, asymmetric nuclear matter in Dirac-Brueckner-Hartree-Fock approach
Katayama, Tetsuya
2013-01-01
Within the Dirac-Brueckner-Hartree-Fock approach, using the Bonn potentials, we investigate the properties of dense, asymmetric nuclear matter and apply it to neutron stars. In the actual calculations of the nucleon self-energies and the energy density of matter, we study in detail the validity of an angle-averaged approximation and an averaging of the total momentum squared of interacting two-nucleons in nuclear matter. For practical use, we provide convenient parametrizations for the equation of state for symmetric nuclear matter and pure neutron matter. We also parametrize the nucleon self-energies in terms of polynomials of nucleon momenta. Those parametrizations can accurately reproduce the numerical results up to high densities.
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.
Single particle potentials of asymmetric nuclear matter in different spin-isospin channels
ZUO Wei; GAN Sheng-Xin; U.Lombardo
2012-01-01
We investigate the neutron and proton single particle (s.p.) potentials of asymmetric nuclear matter and their isospin dependence in various spin-isospin ST channels within the framework of the BruecknerHartree-Fock approach.It is shown that in symmetric nuclear matter,the s.p.potentials in both the isospinsinglet T =0 channel and isospin-triplet T =1 channel are essentially attractive,and the magnitudes in the two different channels are roughly the same.In neutron-rich nuclear matter,the isospin-splitting of the proton and neutron s.p.potentials turns out to be mainly determined by the isospin-singlet T =0 channel contribution which becomes more attractive for the proton and more repulsive for the neutron at higher asymmetries.
D mesons and charmonium states in asymmetric nuclear matter at finite temperatures
Kumar, Arvind
2010-01-01
We investigate the in-medium masses of $D$ and $\\bar{D}$ mesons in the isospin-asymmetric nuclear matter at finite temperatures arising due to the interactions with the nucleons, the scalar isoscalar meson $\\sigma$, and the scalar iso-vector meson $\\delta$ within a SU(4) model. The in-medium masses of $J/\\psi$ and the excited charmonium states ($\\psi(3686)$ and $\\psi(3770)$) are also calculated in the hot isospin asymmetric nuclear matter in the present investigation. These mass modifications arise due to the interaction of the charmonium states with the gluon condensates of QCD, simulated by a scalar dilaton field introduced to incorporate the broken scale invariance of QCD within the effective chiral model. The change in the mass of $J/\\psi$ in the nuclear matter with the density is seen to be rather small, as has been shown in the literature by using various approaches, whereas, the masses of the excited states of charmonium ($\\psi(3686)$ and $\\psi(3770)$) are seen to have considerable drop at high densiti...
Asymmetric nuclear matter based on chiral two- and three-nucleon interactions
Drischler, Christian; Schwenk, Achim
2015-01-01
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 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.
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.
Yilmaz, O.; Acar, F.; Saatci, S. [Middle East Technical University, Physics Department, Ankara (Turkey); Ayik, S. [Tennessee Technological University, Physics Department, Cookeville, TN (United States); Gokalp, A. [Bilkent University, Department of Physics, Ankara (Turkey)
2013-03-15
Early development of spinodal instabilities and density correlation functions in asymmetric nuclear matter are investigated in the stochastic extension of the Walecka-type relativistic mean field including coupling with rho meson. Calculations are performed under typical conditions encountered in heavy-ion collisions and in the crusts of neutron stars. In general, growth of instabilities occur relatively slower for increasing charge asymmetry of matter. At higher densities around {rho} = 0.4{rho} {sub 0} fluctuations grow relatively faster in the quantal description than those found in the semi-classical limit. Typical sizes of early condensation regions extracted from density correlation functions are consistent with those found from dispersion relations of the unstable collective modes. (orig.)
Finite size effects in liquid-gas phase transition of asymmetric nuclear matter
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
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
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.
Isospin and momentum dependence of liquid-gas phase transition in hot asymmetric nuclear matter
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)
Finite temperature collective modes in a two phase coexistence region of asymmetric nuclear matter
Aguirre, R M
2010-01-01
The relation between collective modes and the phase transition in low density nuclear matter is examined. The dispersion relations for collective modes in a linear approach are evaluated within a Landau-Fermi liquid scheme by assuming coexisting phases in thermodynamical equilibrium. Temperature and isospin composition are taken as relevant parameters. The in-medium nuclear interaction is taken from a recently proposed density functional model. We found significative modifications in the energy spectrum, within certain range of temperatures and isospin asymmetry, due to the separation of matter into independent phases. We conclude that detailed calculations should not neglect this effect.
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...
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 ...
Secretly Asymmetric Dark Matter
Agrawal, Prateek; Kilic, Can; Swaminathan, Sivaramakrishnan; Trendafilova, Cynthia
2016-01-01
We study a mechanism where the dark matter number density today arises from asymmetries generated in the dark sector in the early universe, even though total dark matter number remains zero throughout the history of the universe. The dark matter population today can be completely symmetric, with annihilation rates above those expected from thermal WIMPs. We give a simple example of this mechanism using a benchmark model of flavored dark matter. We discuss the experimental signatures of this s...
Kaplan, David E.; Luty, Markus A.; Zurek, Kathryn M.
2009-01-01
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 transfered 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 m...
Secretly Asymmetric Dark Matter
Agrawal, Prateek; Swaminathan, Sivaramakrishnan; Trendafilova, Cynthia
2016-01-01
We study a mechanism where the dark matter number density today arises from asymmetries generated in the dark sector in the early universe, even though total dark matter number remains zero throughout the history of the universe. The dark matter population today can be completely symmetric, with annihilation rates above those expected from thermal WIMPs. We give a simple example of this mechanism using a benchmark model of flavored dark matter. We discuss the experimental signatures of this setup, which arise mainly from the sector that annihilates the symmetric component of dark matter.
Originally Asymmetric Dark Matter
Okada, Nobuchika
2012-01-01
We propose a scenario with a fermion dark matter, where the dark matter particle used to be the Dirac fermion, but it takes the form of the Majorana fermion at a late time. The relic number density of the dark matter is determined by the dark matter asymmetry generated through the same mechanism as leptogenesis when the dark matter was the Dirac fermion. After efficient dark matter annihilation processes have frozen out, a phase transition of a scalar field takes place and generates Majorana mass terms to turn the dark matter particle into the Majorana fermion. In order to address this scenario in detail, we propose two simple models. The first one is based on the Standard Model (SM) gauge group and the dark matter originates the $SU(2)_L$ doublet Dirac fermion, analogous to the Higgsino-like neutralino in supersymmetric models. We estimate the spin-independent/dependent elastic scattering cross sections of this late-time Majorana dark matter with a proton and find the possibility to discover it by the direct...
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.
ZUO Wei; A.Lejeune; U.Lombardo; J.F.Mathiot
2003-01-01
The three-body force effects on the equation of state and its iso-spin dependence of asymmetric nuclearmatter and on the proton fraction in neutron star matter have been investigated within Brueckner-Hartree-Fock approachby using a microscopic three-body force. It is shown that, even in the presence of the three-body force, the empiricalparabolic law of the energy per nucleon vs. isospin asymmetry β＝ ( N - Z) /A is fulfilled in the whole asymmetry range0≤β≤1 and also up to high density. The three-body force provides a strong enhancement of symmetry energy at highdensity in agreement with relativistic approaches. It also shows that the three-body force leads to a much more rapidincreasing of symmetry energy with density in relatively high density region and to a much lower threshold density forthe direct URCA process to occur in a neutron star as compared to the predictions adopting only pure two-body force.
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
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.)
Regenerating a symmetry in asymmetric dark matter.
Buckley, Matthew R; Profumo, Stefano
2012-01-01
Asymmetric dark matter theories generically allow for mass terms that lead to particle-antiparticle mixing. Over the age of the Universe, dark matter can thus oscillate from a purely asymmetric configuration into a symmetric mix of particles and antiparticles, allowing for pair-annihilation processes. Additionally, requiring efficient depletion of the primordial thermal (symmetric) component generically entails large annihilation rates. We show that unless some symmetry completely forbids dark matter particle-antiparticle mixing, asymmetric dark matter is effectively ruled out for a large range of masses, for almost any oscillation time scale shorter than the age of the Universe. PMID:22304253
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 ...
Chamel, Nicolas; Goriely, Stéphane
2010-01-01
Self-consistent mean-field methods based on phenomenological Skyrme effective interactions are known to exhibit spurious spin and spin-isospin instabilities both at zero and finite temperatures when applied to homogeneous nuclear matter at the densities encountered in neutron stars and in supernova cores. The origin of these instabilities is revisited in the framework of the nuclear energy density functional theory, and a simple prescription is proposed to remove them. The stability of severa...
Aidala, C; Akiba, Y; Akimoto, R; Alexander, J; Aoki, K; Apadula, N; Asano, H; Atomssa, E T; Awes, T C; Azmoun, B; Babintsev, V; Bai, M; Bai, X; Bannier, B; Barish, K N; Bathe, S; Baublis, V; Baumann, C; Baumgart, S; Bazilevsky, A; Beaumier, M; Belmont, R; Berdnikov, A; Berdnikov, Y; Bing, X; Black, D; Blau, D S; Bok, J; Boyle, K; Brooks, M L; Bryslawskyj, J; Buesching, H; Bumazhnov, V; Butsyk, S; Campbell, S; Chen, C -H; Chi, C Y; Chiu, M; Choi, I J; Choi, J B; Choi, S; Christiansen, P; Chujo, T; Cianciolo, V; Cole, B A; Cronin, N; Crossette, N; Csanád, M; Csörgő, 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; Slunečka, M; Solano, S; Soltz, R A; Sondheim, W E; Sorensen, S P; Soumya, M; Sourikova, I V; Stankus, P W; Steinberg, P; Stenlund, E; Stepanov, M; Ster, A; Stoll, S P; Stone, M R; Sugitate, T; Sukhanov, A; Sun, J; Takahara, A; Taketani, A; Tanida, K; Tannenbaum, M J; Tarafdar, S; Taranenko, A; Tennant, E; Timilsina, A; Todoroki, T; Tomášek, M; Torii, H; Towell, R S; Tserruya, I; van Hecke, H W; Vargyas, M; Vazquez-Zambrano, E; Veicht, A; Velkovska, J; Vértesi, R; Virius, M; Vrba, V; Vznuzdaev, E; Wang, X R; Watanabe, D; Watanabe, K; Watanabe, Y; Watanabe, Y S; Wei, F; Whitaker, S; Wolin, S; Woody, C L; Wysocki, M; Yamaguchi, Y L; Yanovich, A; Yokkaichi, S; Yoon, I; You, Z; Younus, I; Yushmanov, I E; Zajc, W A; Zelenski, A; Zhou, S
2014-01-01
We report on $J/\\psi$ production from asymmetric Cu+Au heavy-ion collisions at $\\sqrt{s_{_{NN}}}$=200 GeV at the Relativistic Heavy Ion Collider at both forward (Cu-going direction) and backward (Au-going direction) rapidities. The nuclear modification of $J/\\psi$ yields in Cu$+$Au collisions in the Au-going direction is found to be comparable to that in Au$+$Au collisions when plotted as a function of the number of participating nucleons. In the Cu-going direction, $J/\\psi$ production shows a stronger suppression. This difference is comparable in magnitude and has the same sign as the difference expected from shadowing effects due to stronger low-$x$ gluon suppression in the larger Au nucleus. The relative suppression is opposite to that expected from hot nuclear matter dissociation, since a higher energy density is expected in the Au-going direction.
Asymmetric dark matter from hidden sector baryogenesis
Dutta, Bhaskar [Department of Physics and Astronomy, Mitchell Institute for Fundamental Physics, Texas A and M University, College Station, TX 77843 (United States); Kumar, Jason, E-mail: jkumar@hawaii.edu [Department of Physics and Astronomy, University of Hawai' i, Honolulu, HI 96822 (United States)
2011-05-23
We consider the production of asymmetric dark matter during hidden sector baryogenesis. We consider a particular supersymmetric model where the dark matter candidate has a number density approximately equal to the baryon number density, with a mass of the same scale as the b, c and {tau}. Both baryon asymmetry and dark matter are created at the same time in this model. We describe collider and direct detection signatures of this model.
Isospin violating dark matter being asymmetric
Okada, Nobuchika
2013-01-01
The isospin violating dark matter (IVDM) scenario offers an interesting possibility to reconcile conflicting results among direct dark matter search experiments for a mass range around 10 GeV. We consider two simple renormalizable IVDM models with a complex scalar dark matter and a Dirac fermion dark matter, respectively, whose stability is ensured by the conservation of "dark matter number". Although both models successfully work as the IVDM scenario with destructive interference between effective couplings to proton and neutron, the dark matter annihilation cross section is found to exceed the cosmological/astrophysical upper bounds. Then, we propose a simple scenario to reconcile the IVDM scenario with the cosmological/astrophysical bounds, namely, the IVDM being asymmetric. Assuming a suitable amount of dark matter asymmetry has been generated in the early Universe, the annihilation cross section beyond the cosmological/astrophysical upper bound nicely works to dramatically reduce the anti-dark matter rel...
Yong, Gao-Chan
2015-01-01
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.
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.
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...
The phases of isospin asymmetric matter in the two flavor NJL model
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.
Aidala, C.; Ajitanand, N. N.; 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.
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 ...
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 .
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 ...
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. Provid
It is stated that at the Workshop on Nuclear and Dense Matter held at the University of Illinois in May 1977 significant progress was reported that largely resolves many of the questions raised in this journal Vol. 6, p.149, 1976. These include perturbative versus variational methods as applied to nuclear matter, exact solutions for bosons, what is known as the fermion 'homework problem', and various other considerations regarding nuclear matter, including the use of variational methods as opposed to perturbation theory. (15 references) (U.K.)
Isospin and density dependencies of nuclear matter symmetry energy coefficients
Symmetry energy coefficients of explicitly isospin asymmetric nuclear matter at variable densities (from 0.5ρ0 up to 2ρ0) are studied as generalized screening functions. An extended stability condition for asymmetric nuclear matter is proposed. We find the possibility of obtaining stable asymmetric nuclear matter even in some cases for which the symmetric nuclear matter limit is unstable. Skyrme-type forces are extensively used in analytical expressions of the symmetry energy coefficients derived as generalized screening functions in the four channels of the particle hole interaction producing alternative behaviors at different ρ and b (respectively, the density and the asymmetry coefficient). The spin and spin-isospin coefficients, with corrections to the usual Landau Migdal parameters, indicate the possibility of occurring instabilities with common features depending on the nuclear density and n–p asymmetry. Possible relevance for high energy heavy ions collisions and astrophysical objects is discussed. (author)
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.
Asymmetric Dark Matter Models and the LHC Diphoton Excess
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...... 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
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...
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.
Gamma ray constraints on flavor violating asymmetric dark matter
Masina, I.; Panci, P.; Sannino, F.
2012-01-01
We show how cosmic gamma rays can be used to constrain models of asymmetric Dark Matter decaying into lepton pairs by violating flavor. First of all we require the models to explain the anomalies in the charged cosmic rays measured by PAMELA, Fermi and H.E.S.S.; performing combined fits we...... determine the allowed values of the Dark Matter mass and lifetime. For these models, we then determine the constraints coming from the measurement of the isotropic gamma-ray background by Fermi for a complete set of lepton flavor violating primary modes and over a range of DM masses from 100 GeV to 10 Te......V. We find that the Fermi constraints rule out the flavor violating asymmetric Dark Matter interpretation of the charged cosmic ray anomalies....
Limits on Momentum-Dependent Asymmetric Dark Matter with CRESST-II
Angloher, G.; Bento, A.; Bucci, C.; Canonica, L.; Defay, X.; Erb, A.; Feilitzsch, F. v.; Ferreiro Iachellini, N.; 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.; Trinh Thi, H. H.; Türkoǧlu, C.; Uffinger, M.; Ulrich, A.; Usherov, I.; Wawoczny, S.; Willers, M.; Wüstrich, M.; Zöller, A.
2016-07-01
The usual assumption in direct dark matter searches is to consider only the spin-dependent or spin-independent scattering of dark matter particles. However, especially in models with light dark matter particles O (GeV /c2 ) , operators which carry additional powers of the momentum transfer q2 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 a preferred mass of 3 GeV /c2 and a cross section of 10-37 cm2 . Recent data from the CRESST-II experiment, which uses cryogenic detectors based on CaWO4 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.
Kaon polarization in nuclear matter
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 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
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
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...
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 ...
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)
Magnetic catalysis in nuclear matter
Haber, Alexander; Preis, Florian; Schmitt, Andreas
2014-01-01
A strong magnetic field enhances the chiral condensate at low temperatures. This so-called magnetic catalysis thus seeks to increase the vacuum mass of nucleons. We employ two relativistic field-theoretical models for nuclear matter, the Walecka model and an extended linear sigma model, to discuss the resulting effect on the transition between vacuum and nuclear matter at zero temperature. In both models we find that the creation of nuclear matter in a sufficiently strong magnetic field becom...
Nuclear matter and electron scattering
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.)
Propagation of neutrinos in nuclear matter
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)
Covariant density functional theory for nuclear matter
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.)
Covariant density functional theory for nuclear matter
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.)
Functional renormalization group study of nuclear and neutron matter
Drews, Matthias; Weise, Wolfram [Physik Department, Technische Universität München, D-85747 Garching (Germany); ECT*, Villa Tambosi, I-38123 Villazzano (Trento) (Italy)
2016-01-22
A chiral model based on nucleons interacting via boson exchange is investigated. Fluctuation effects are included consistently beyond the mean-field approximation in the framework of the functional renormalization group. The liquid-gas phase transition of symmetric nuclear matter is studied in detail. No sign of a chiral restoration transition is found up to temperatures of about 100 MeV and densities of at least three times the density of normal nuclear matter. Moreover, the model is extended to asymmetric nuclear matter and the constraints from neutron star observations are discussed.
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
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
Chiral thermodynamics of nuclear matter
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
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.
Charmonium mass in nuclear matter
Ko, C. M.; Lee, Su Houng
2002-01-01
The mass shift of charmonium states in nuclear matter is studied in the perturbative QCD approach. The leading-order effect due to the change of gluon condensate in nuclear matter is evaluated using the leading-order QCD formula, while the higher-twist effect due to the partial restoration of chiral symmetry is estimated using a hadronic model. We find that while the mass of $J/\\psi$ in nuclear matter decreases only slightly, those of $\\psi(3686)$ and $\\psi(3770)$ states are reduced appreciab...
What can we learn from nuclear matter instabilities
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)
Nuclear fusion inside condense matters
HE Jing-tang
2007-01-01
This article describes in detail the nuclear fusion inside condense matters--the Fleischmann-Pons effect, the reproducibility of cold fusions, self-consistentcy of cold fusions and the possible applications.
Shear viscosity of nuclear matter
This paper reports my recent study[1] 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. Dependence 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. (authors)
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.
Limits on Momentum-Dependent Asymmetric Dark Matter with CRESST-II.
Angloher, G; Bento, A; Bucci, C; Canonica, L; Defay, X; Erb, A; Feilitzsch, F V; Ferreiro Iachellini, N; 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; Trinh Thi, H H; Türkoğlu, C; Uffinger, M; Ulrich, A; Usherov, I; Wawoczny, S; Willers, M; Wüstrich, M; Zöller, A
2016-07-01
The usual assumption in direct dark matter searches is to consider only the spin-dependent or spin-independent scattering of dark matter particles. However, especially in models with light dark matter particles O(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 a preferred mass of 3 GeV/c^{2} and a cross section of 10^{-37} cm^{2}. Recent data from the CRESST-II experiment, which uses cryogenic detectors based on 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. PMID:27447498
Bottomonium states in hot asymmetric strange hadronic matter
Mishra, Amruta
2014-01-01
We calculate the in-medium masses of the bottomonium states ($\\Upsilon(1S)$, $\\Upsilon(2S)$, $\\Upsilon(3S)$ and $\\Upsilon(4S)$) in isospin asymmetric strange hadronic matter at finite temperatures. The medium modifications of the masses arise due to the interaction of these heavy quarkonium states with the gluon condensates of QCD. The gluon condensates in the hot hadronic matter are computed from the medium modification of a scalar dilaton field within a chiral SU(3) model, introduced in the hadronic model to incorporate the broken scale invariance of QCD. There is seen to be drop in the masses of the bottomonium states and the mass shifts are observed to be quite considerable at high densities for the excited states. The effects of density, isospin asymmetry, strangeness as well as temperature of the medium on the masses of the $\\Upsilon$-states are investigated. The effects of the isopsin asymmetry as well as strangeness fraction of the medium are seen to be appreciable at high densities and small temperat...
Bosonic variables in nuclear matters
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
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.
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.
Aspects of particle production in isospin-asymmetric matter
The production/absorption rate of particles in compressed and heated asymmetric matter is studied using a Relativistic Mean Field (RMF) transport model with an isospin-dependent collision term. Just from energy conservation in the elementary production/absorption processes we expect to see a strong dependence of the yields on the basic Lorentz structure of the isovector effective interaction, due to isospin effects on the scalar and vector self-energies of the hadrons. This will be particularly evident for the ratio of the rates of particles produced with different charges: results are shown for π+/π-, K+/K0 yields. In order to simplify the analysis we perform RMF cascade simulations in a box with periodic boundary conditions. In this way we can better pin down all such fine relativistic effects in particle production, that could likely show up even in realistic heavy ion collisions. In fact, the box properties are tuned in order to reproduce the heated dense matter formed during a nucleus-nucleus collision in the few A-bar GeV beam energy region. In particular, K+,0 production is expected to be directly related to the high density behaviour of the symmetry energy, since kaons are produced very early during the high density stage of the collision and their mean free path is rather large. We show that the K+/K0 ratio reflects important isospin contributions on the production rates just because of the large sensitivity around the threshold. The results are very promising for the possibility of a direct link between particle production data in exotic Heavy Ion Collisions (HIC) and the isospin-dependent part of the Equation of State (EoS) at high baryon densities
Detecting Asymmetric Dark Matter in the Sun with Neutrinos
Murase, Kohta
2016-01-01
Dark Matter (DM) may have a relic density that is in part determined by a particle/antiparticle asymmetry, much like baryons. If this is the case, it can accumulate in stars like the Sun to sizable number densities and annihilate to Standard Model (SM) particles including neutrinos. We show that the combination of neutrino telescope and direct detection data can be used in conjunction to determine or constrain the DM asymmetry from data. Depending on the DM mass, the current neutrino data from Super-K and IceCube give powerful constraints on asymmetric DM unless its fractional asymmetry is $\\lesssim 10^{-2}$. Future neutrino telescopes and detectors like Hyper-K and KM3NeT can search for the resulting signal of high-energy neutrinos from the center of the Sun. The observation of such a flux yields information on both the DM-nucleus cross section but also on the relative abundances of DM and anti-DM.
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
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
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.)
Instability in relativistic nuclear matter
The stability of the Fermi gas state in the nuclear matter which satisfies the saturation property is considered relativistically. It is shown that the Fermi gas state is stable at very low density and at high density, but it is unstable for density fluctuation in the intermediate density region including the normal density. (author)
Heavy Hadrons in Nuclear Matter
Hosaka, Atsushi; Sudoh, Kazutaka; Yamaguchi, Yasuhiro; Yasui, Shigehiro
2016-01-01
Current studies on heavy hadrons in nuclear medium are reviewed with a summary of the basic theoretical concepts of QCD, namely chiral symmetry, heavy quark spin symmetry, and the effective Lagrangian approach. The nuclear matter is an interesting place to study the properties of heavy hadrons from many different points of view. We emphasize the importance of the following topics: (i) charm/bottom hadron-nucleon interaction, (ii) structure of charm/bottom nuclei, and (iii) QCD vacuum properties and hadron modifications in nuclear medium. We pick up three different groups of heavy hadrons, quarkonia ($J/\\psi$, $\\Upsilon$), heavy-light mesons ($D$/$\\bar{D}$, $\\bar{B}$/$B$) and heavy baryons ($\\Lambda_{c}$, $\\Lambda_{b}$). The modifications of those hadrons in nuclear matter provide us with important information to investigate the essential properties of heavy hadrons. We also give the discussions about the heavy hadrons, not only in nuclear matter with infinite volume, but also in atomic nuclei with finite bary...
Big Bang synthesis of nuclear dark matter
Hardy, Edward; Lasenby, Robert; March-Russell, John; West, Stephen M.
2015-06-01
We investigate the physics of dark matter models featuring composite bound states carrying a large conserved dark "nucleon" number. The properties of sufficiently large dark nuclei may obey simple scaling laws, and we find that this scaling can determine the number distribution of nuclei resulting from Big Bang Dark Nucleosynthesis. For plausible models of asymmetric dark matter, dark nuclei of large nucleon number, e.g. ≳ 108, may be synthesised, with the number distribution taking one of two characteristic forms. If small-nucleon-number fusions are sufficiently fast, the distribution of dark nuclei takes on a logarithmically-peaked, universal form, independent of many details of the initial conditions and small-number interactions. In the case of a substantial bottleneck to nucleosynthesis for small dark nuclei, we find the surprising result that even larger nuclei, with size ≫ 108, are often finally synthesised, again with a simple number distribution. We briefly discuss the constraints arising from the novel dark sector energetics, and the extended set of (often parametrically light) dark sector states that can occur in complete models of nuclear dark matter. The physics of the coherent enhancement of direct detection signals, the nature of the accompanying dark-sector form factors, and the possible modifications to astrophysical processes are discussed in detail in a companion paper.
DS Mesons in Asymmetric Hot and Dense Hadronic Matter
Divakar Pathak
2015-01-01
Full Text Available The in-medium properties of DS mesons are investigated within the framework of an effective hadronic model, which is a generalization of a chiral SU(3 model, to SU(4, in order to study the interactions of the charmed hadrons. In the present work, the DS mesons are observed to experience net attractive interactions in a dense hadronic medium, hence reducing the masses of the DS+ and DS- 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 DS 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 DS+ and DS- 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 are all expected to make a significant difference to observables in heavy ion collision experiments, especially the upcoming Compressed Baryonic Matter (CBM experiment at the future Facility for Antiproton and Ion Research (FAIR, GSI, where matter at high baryonic densities is planned to be produced.
Reflection-asymmetric nuclear deformations within the Density Functional Theory
Olsen, E; Nazarewicz, W; Stoitsov, M; 10.1088/1742-6596/402/1/012034
2013-01-01
Within the nuclear density functional theory (DFT) we study the effect of reflection-asymmetric shapes on ground-state binding energies and binding energy differences. To this end, we developed the new DFT solver AxialHFB that uses an approximate second-order gradient to solve the Hartree-Fock-Bogoliubov equations of superconducting DFT with the quasi-local Skyrme energy density functionals. Illustrative calculations are carried out for even-even isotopes of radium and thorium.
Temperature Dependent Nuclear Matter Approach
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)
Effects of gravitational confinement on bosonic asymmetric dark matter in stars
Jamison, Alan O
2013-01-01
Considering the existence of old neutron stars puts strong limits on the dark matter/nucleon cross section for bosonic asymmetric dark matter. Key to these bounds is formation of a Bose-Einstein condensate (BEC) of the asymmetric dark matter particles. We consider the effects of the host neutron star's gravitational field on the BEC transition. We find this substantially shifts the transition temperature and so strengthens the bounds on cross section. In particular, for the well-motivated mass range of ~5-15 GeV, we improve previous bounds by an order of magnitude.
Role of isospin in nuclear-matter liquid-gas phase transition
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)
Covariant density functional theory for nuclear matter
Badarch, Urnaa
2007-01-01
The EOS of nuclear matter is studied in the framework of relativistic density dependent hadron field theory (DDRH) and results are compared to the results of the phenomenological density dependent approach DD-ME1 which is devised to fit the properties of the symmetric nuclear matter around the normal nuclear matter density . Nuclear interactions were described by a covariant density functional theory using baryons and mesons. In this work medium dependent modifications of ...
Nuclear charge and neutron radii and nuclear matter: trend analysis
Reinhard, P. -G.; W. Nazarewicz
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...
Main Achievements 2003-2004 - Theoretical hadronic physics - Nuclear matter
In the fundamental field of the many-body problem of strongly interacting particles major successes were achieved. We have performed a fully consistent description of the dynamical response functions in strongly correlated fermionic systems and carried out a new self-consistent and symmetry-conserving calculation of the nucleon spectral function in asymmetric nuclear medium, connected to the analysis of vertex functions and self-energy corrections in medium. These studies have applications to studies of the nuclear medium as well as condensed matter
Charmed mesons in nuclear matter
Tolos, L; Garcia-Recio, C; Oset, E; Molina, R; Nieves, J; Ramos, A
2010-01-01
We obtain the properties of charmed mesons in dense matter using a coupled-channel approach which accounts for Pauli blocking effects and meson self-energies in a self-consistent manner. We study the behaviour of dynamically-generated baryonic resonances together with the open-charm meson spectral functions in this dense nuclear environment. We discuss the implications of the in-medium properties of open-charm mesons on the $D_{s0}(2317)$ and the predicted X(3700) scalar resonances, and on the formation of $D$-mesic nuclei.
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.
Nuclear interactions and hadronic matter
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
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...
Baryogenesis and asymmetric dark matter from the left–right mirror symmetric model
The paper suggests a left–right mirror symmetric model to account for the baryogenesis and asymmetric dark matter. The model can simultaneously accommodate the standard model, neutrino physics, matter–antimatter asymmetry and dark matter. In particular, it naturally and elegantly explains the origin of the baryon and dark matter asymmetries, and clearly gives the close interrelations of them. In addition, the model predicts a number of interesting results, e.g. 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-matter symmetry coefficient and nuclear masses
Pearson, J M
2000-01-01
Within the framework of the ETFSI (extended Thomas-Fermi plus Strutinsky integral) mass formula, a precision fit of nuclear masses with Skyrme forces, subject to the constraint that neutron matter does not collapse at nuclear or subnuclear densities, is possible if, but only if, the nuclear-matter symmetry coefficient J lies close to 28 MeV.
Carbone, Arianna; Rios, Arnau; Vidaña, Isaac
2010-01-01
We study the latent heat of the liquid-gas phase transition in symmetric nuclear matter using self-consistent mean-field calculations with a few Skyrme forces. The temperature dependence of the latent heat is rather independent of the mean-field parametrization and can be characterized by a few parameters. At low temperatures, the latent heat tends to the saturation energy. Near the critical point, the latent heat goes to zero with a well-determined mean-field critical exponent. A maximum value of the latent heat in the range l ~ 25-30 MeV is found at intermediate temperatures, which might have experimental relevance. All these features can be explained from very basic principles.
Leptonic Indirect Detection Signals from Strongly Interacting Asymmetric Dark Matter
Cai, Yi; Kaplan, David E.; Luty, Markus A.
2009-01-01
Particles with TeV mass and strong self-interactions generically have the right annihilation cross section to explain an observed excess of cosmic electrons and positrons if the end-product of the annihilation is charged leptons. We present an explicit model of strongly-coupled TeV-scale dark matter whose relic abundance related to the matter-antimatter asymmetry of the observed universe. The B - L asymmetry of the standard model is transfered to the dark sector by an operator carrying standa...
Charge Asymmetric Cosmic Ray Signals From Dark Matter Decay
Chang, Spencer; Goodenough, Lisa
2011-01-01
The PAMELA and Fermi measurements of the cosmic-ray electron and positron spectra have generated much interest over the past two years, because they are consistent with a significant component of the electron and positron fluxes between 20 GeV and 1 TeV being produced through dark matter annihilation or decay. However, since the measurements are also consistent with astrophysical interpretations, the message is unclear. In this paper, we point out that dark matter can have a more distinct sig...
Light asymmetric dark matter from new strong dynamics
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...
Towards the nuclear matter - quark matter phase transition
The conjectured first order phase transition from cold nuclear to cold quark matter is considered. It is found that non-perturbative effects due to instantons may have a 'smoothing-out' effect on the transition. (author)
Asymmetric dark matter from spontaneous cogenesis in the supersymmetric standard model
Kamada, Kohei [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Yamaguchi, Masahide [Tokyo Institute of Technology (Japan). Dept. of Physics
2012-01-15
The observational relation between the density of baryon and dark matter in the Universe, {omega}{sub DM}/{omega}{sub B}{approx_equal}5, is one of the most difficult problems to solve in modern cosmology. We discuss a scenario that explains this relation by combining the asymmetric dark matter scenario and the spontaneous baryogenesis associated with the flat direction in the supersymmetric standard model. A part of baryon asymmetry is transferred to charge asymmetry D that dark matter carries, if a symmetry violating interaction that works at high temperature breaks not only B-L but also D symmetries simultaneously. In this case, the present number density of baryon and dark matter can be same order if the symmetric part of dark matter annihilates sufficiently. Moreover, the baryon number density can be enhanced as compared to that of dark matter if another B-L violating interaction is still in thermal equilibrium after the spontaneous genesis of dark matter, which accommodates a TeV scale asymmetric dark matter model. (orig.)
Clusters in nuclear matter and Mott points
Röpke, 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 saturatio...
Asymmetrical sabotage tactics, nuclear facilities/materials, and vulnerability analysis
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)
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.
Asymmetric dark matter and CP violating scatterings in a UV complete model
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
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
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...
Detecting Asymmetric Dark Matter in the Sun with Neutrinos
Murase, Kohta; Shoemaker, Ian M.
2016-01-01
Dark Matter (DM) may have a relic density that is in part determined by a particle/antiparticle asymmetry, much like baryons. If this is the case, it can accumulate in stars like the Sun to sizable number densities and annihilate to Standard Model (SM) particles including neutrinos. We show that the combination of neutrino telescope and direct detection data can be used in conjunction to determine or constrain the DM asymmetry from data. Depending on the DM mass, the current neutrino data fro...
Hyperons in nuclear matter from SU(3) chiral effective field theory
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.)
Cosmic ray-dark matter scattering: a new signature of (asymmetric) dark matter in the gamma ray sky
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
Nuclear matter, nuclear and subnuclear degrees of freedom
Alberico, Wanda M.
1999-01-01
We report here theoretical investigations on the complexity of nuclear structure, which have been carried out in the framework of different many-body approaches, typically applied to nuclear matter and quark matter studies. The variational, functional and perturbative scheme are illustrated in their latest developments. The effect of various nucleon-nucleon interactions are tested, particularly in the context of the nuclear response functions, against a large body of experimental data. The pr...
Skyrmions, dense matter and nuclear forces
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
Tolos, Laura; Garcia-Recio, Carmen; Molina, Raquel; Nieves, Juan; Oset, Eulogio; Ramos, Angels; Romanets, Olena; Salcedo, Lorenzo Luis; Torres-Rincon, Juan M
2014-01-01
Heavy mesons in nuclear matter and nuclei are analyzed within different frameworks, paying a special attention to unitarized coupled-channel approaches. Possible experimental signatures of the properties of these mesons in matter are addressed, in particular in connection with the future FAIR facility at GSI.
Heavy Mesons in Nuclear Matter and Nuclei
Heavy mesons in nuclear matter and nuclei are analyzed within different frameworks, paying a special attention to unitarized coupled-channel approaches. Possible experimental signatures of the properties of these mesons in matter are addressed, in particular in connection with the future FAIR facility at GSI
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
Röpke, 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.
Describing Nuclear Matter with Effective Field Theories
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
Nucleon mean free path in nuclear matter
In calculations of nuclear reaction yields at incident energies of some tens of MeV consistently better agreement with experiments is obtained by assuming a nucleon mean free path in nuclear matter longer than that deduced from the Fermi gas model and free nucleon-nucleon cross sections. (Auth.)
The single particle potential in nuclear matter
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.)
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.
Nuclear matter in all its states
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
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 ...
Isospin effect on elliptical flow for mass asymmetric nuclear collisions
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
Femtotechnology: Nuclear Matter with Fantastic Properties
A. A. Bolonkin
2009-01-01
Full Text Available Problem statement: At present the term 'nanotechnology' is well known-in its' ideal form, the flawless and completely controlled design of conventional molecular matter from molecules or atoms. Such a power over nature would offer routine achievement of remarkable properties in conventional matter and creation of metamaterials where the structure not the composition brings forth new powers of matter. But even this yet unachieved goal is not the end of material science possibilities. The author herein offers the idea of design of new forms of nuclear matter from nucleons (neutrons, protons, electrons and other nuclear particles. Approach: The researcher researches the nuclear forces. He shows these force may be used for design the new nuclear matter from protons, neutrons, electrons and other nuclear particles. Results: Author shows this new 'AB-Matter' has extraordinary properties (for example, tensile strength, stiffness, hardness, critical temperature, superconductivity, supertransparency and zero friction., which are up to millions of times better than corresponding properties of conventional molecular matter. He shows concepts of design for aircraft, ships, transportation, thermonuclear reactors, constructions and so on from nuclear matter. These vehicles will have unbelievable possibilities (e.g., invisibility, ghost-like penetration through any walls and armor, protection from nuclear bomb explosions and any radiation flux. Conclusion: People may think this fantasy. But fifteen years ago most people and many scientists thought-nanotechnology is fantasy. Now many groups and industrial labs, even startups, spend hundreds of millions of dollars for development of nanotechnological-range products (precise chemistry, patterned atoms, catalysts and meta-materials and we have nanotubes (a new material which does not exist in Nature! and other achievements beginning to come out of the pipeline in prospect. Nanotubes are stronger than steel by a
Equation of state for isospin asymmetric matter of nucleons and deltas
An investigation on the equation of state of the isospin asymmetric, hot, dense matter of nucleons and deltas is performed based on the relativistic mean Geld theory. The QHD-Ⅱ-type effective Lagrangian extending to the delta degree of freedom is adopted. Our results show that the equation of state is softened due to the inclusion of the delta degree of freedom. The baryon resonance isomer may occur depending on the delta-meson coupling. The results show that the densities for appearing the baryon resonance isomer, the densities for starting softening the equation of state and the extent of the softening depend not only on the temperature, the coupling strengths but also the isospin asymmetry of the baryon matter. (authors)
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.
Nuclear matter with constituent meson quanta
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
Condensed matter studies by nuclear methods
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.)
Moments of ϕ meson spectral functions in vacuum and nuclear matter
Gubler, Philipp; Weise, Wolfram
2015-12-01
Moments of the ϕ meson spectral function in vacuum and in nuclear matter are analyzed, combining a model based on chiral SU (3) effective field theory (with kaonic degrees of freedom) and finite-energy QCD sum rules. For the vacuum we show that the spectral density is strongly constrained by a recent accurate measurement of the e+e- →K+K- cross section. In nuclear matter the ϕ spectrum is modified by interactions of the decay kaons with the surrounding nuclear medium, leading to a significant broadening and an asymmetric deformation of the ϕ meson peak. We demonstrate that both in vacuum and nuclear matter, the first two moments of the spectral function are compatible with finite-energy QCD sum rules. A brief discussion of the next-higher spectral moment involving strange four-quark condensates is also presented.
Probing cold dense nuclear matter
The protons and neutrons in a nucleus can form strongly correlated nucleon pairs. Scattering experiments, in which a proton is knocked out of the nucleus with high-momentum transfer and high missing momentum, show that in carbon-12 the neutron-proton pairs are nearly 20 times as prevalent as proton-proton pairs and, by inference, neutron-neutron pairs. This difference between the types of pairs is due to the nature of the strong force and has implications for understanding cold dense nuclear systems such as neutron stars
Probing Cold Dense Nuclear Matter
The protons and neutrons in a nucleus can form strongly correlated nucleon pairs. Scattering experiments, in which a proton is knocked out of the nucleus with high-momentum transfer and high missing momentum, show that in carbon-12 the neutron-proton pairs are nearly 20 times as prevalent as proton-proton pairs and, by inference, neutron-neutron pairs. This difference between the types of pairs is due to the nature of the strong force and has implications for understanding cold dense nuclear systems such as neutron stars.
Probing cold dense nuclear matter.
Subedi, R.; Monaghan, P.; Shneor, R.; Anderson, B. D.; Aniol, K.; Arrington, J.; Physics; Kent State Univ.; Tel Aviv Univ.; California State Univ. Los Angeles
2008-06-13
The protons and neutrons in a nucleus can form strongly correlated nucleon pairs. Scattering experiments, in which a proton is knocked out of the nucleus with high-momentum transfer and high missing momentum, show that in carbon-12 the neutron-proton pairs are nearly 20 times as prevalent as proton-proton pairs and, by inference, neutron-neutron pairs. This difference between the types of pairs is due to the nature of the strong force and has implications for understanding cold dense nuclear systems such as neutron stars.
Probing Cold Dense Nuclear Matter
Subedi, Ramesh; Shneor, R.; Monaghan, Peter; Anderson, Bryon; Aniol, Konrad; Annand, John; Arrington, John; Benaoum, Hachemi; Benmokhtar, Fatiha; Bertozzi, William; Boeglin, Werner; Chen, Jian-Ping; Choi, Seonho; Cisbani, Evaristo; Craver, Brandon; Frullani, Salvatore; Garibaldi, Franco; Gilad, Shalev; Gilman, Ronald; Glamazdin, Oleksandr; Hansen, Jens-Ole; Higinbotham, Douglas; Holmstrom, Timothy; Ibrahim, Hassan; Igarashi, Ryuichi; De Jager, Cornelis; Jans, Eddy; Jiang, Xiaodong; Kaufman, Lisa; Kelleher, Aidan; Kolarkar, Ameya; Kumbartzki, Gerfried; LeRose, John; Lindgren, Richard; Liyanage, Nilanga; Margaziotis, Demetrius; Markowitz, Pete; Marrone, Stefano; Mazouz, Malek; Meekins, David; Michaels, Robert; Moffit, Bryan; Perdrisat, Charles; Piasetzky, Eliazer; Potokar, Milan; Punjabi, Vina; Qiang, Yi; Reinhold, Joerg; Ron, Guy; Rosner, Guenther; Saha, Arunava; Sawatzky, Bradley; Shahinyan, Albert; Sirca, Simon; Slifer, Karl; Solvignon, Patricia; Sulkosky, Vince; Sulkosky, Vincent; Sulkosky, Vince; Sulkosky, Vincent; Urciuoli, Guido; Voutier, Eric; Watson, John; Weinstein, Lawrence; Wojtsekhowski, Bogdan; Wood, Stephen; Zheng, Xiaochao; Zhu, Lingyan
2008-06-01
The protons and neutrons in a nucleus can form strongly correlated nucleon pairs. Scattering experiments, in which a proton is knocked out of the nucleus with high-momentum transfer and high missing momentum, show that in carbon-12 the neutron-proton pairs are nearly 20 times as prevalent as proton-proton pairs and, by inference, neutron-neutron pairs. This difference between the types of pairs is due to the nature of the strong force and has implications for understanding cold dense nuclear systems such as neutron stars.
Probing Cold Dense Nuclear Matter
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.
D-mesons and charmonium states in hot isospin asymmetric strange hadronic matter
Kumar, Arvind; Mishra, Amruta [Indian Institute of Technology, Delhi, Hauz Khas, Department of Physics, New Delhi (India)
2011-12-15
We study the properties of D and anti D mesons in hot isospin asymmetric strange hadronic matter, arising due to their interactions with the hadrons in the hyperonic medium. The interactions of D and anti D mesons with these light hadrons are derived by generalizing the chiral SU(3) model used for the study of hyperonic matter to SU(4). The nucleons, hyperons, the scalar isoscalar meson, {sigma} and the scalar-isovector meson, {delta} as modified in the strange hadronic matter, modify the masses of D and anti D mesons. It is found that, as compared to the anti D mesons (anti D{sup 0}, D{sup -}), the properties of the D mesons (D{sup 0}, D {sup +}) are more sensitive to the isospin asymmetry at high densities. On the other hand, the effects of strangeness fraction are found to be more dominant for the anti D mesons as compared to the D mesons and these modifications are observed to be particularly appreciable at high densities. We also study the mass modifications of the charmonium states J/{psi}, {psi}(3686) and {psi}(3770) in the isospin asymmetric strange hadronic matter at finite temperatures and investigate the possibility of the decay of the charmonium states into D anti D pairs in the hot hadronic medium. The mass modifications of these charmonium states arise due to their interaction with the gluon condensates of QCD, simulated by a scalar dilaton field introduced to incorporate the broken scale invariance of QCD within the effective chiral model. The effects of finite quark masses are taken into account in the trace of the energy momentum tensor in QCD, while investigating the medium modification of the charmonium masses through the modification of the gluon condensate in the medium. We also compute the partial decay widths of the charmonium states to the D anti D pairs in the hadronic medium. The strong dependence on density of the in-medium properties of the D, anti D and the charmonium states, as well as the partial decay widths of charmonium states to D
Towards Nuclear Physics of OHe Dark Matter
Khlopov, Maxim Yu; Soldatov, Evgeny Yu
2011-01-01
The nonbaryonic dark matter of the Universe can consist of new stable charged particles, bound in heavy "atoms" by ordinary Coulomb interaction. If stable particles $O^{--}$ with charge -2 are in excess over their antiparticles (with charge +2), the primordial helium, formed in Big Bang Nucleosynthesis, captures all $O^{--}$ in neutral "atoms" of O-helium (OHe). Interaction with nuclei plays crucial role in the cosmological evolution of OHe and in the effects of these dark atoms as nuclear interacting dark matter. Slowed down in terrestrial matter OHe atoms cause negligible effects of nuclear recoil in underground detectors, but can experience radiative capture by nuclei. Local concentration of OHe in the matter of detectors is rapidly adjusted to the incoming flux of cosmic OHe and possess annual modulation due to Earth's orbital motion around the Sun. The potential of OHe-nucleus interaction is determined by polarization of OHe by the Coulomb and nuclear force of the approaching nucleus. Stark-like effect b...
Chiral density wave in nuclear matter
Inspired by recent work on inhomogeneous chiral condensation in cold, dense quark matter within models featuring quark degrees of freedom, we investigate the chiral density-wave solution in nuclear matter at zero temperature and nonvanishing baryon number density in the framework of the so-called extended linear sigma model (eLSM). The eLSM is an effective model for the strong interaction based on the global chiral symmetry of quantum chromodynamics (QCD). It contains scalar, pseudoscalar, vector, and axial-vector mesons as well as baryons. In the latter sector, the nucleon and its chiral partner are introduced as parity doublets in the mirror assignment. The eLSM simultaneously provides a good description of hadrons in vacuum as well as nuclear matter ground-state properties. We find that an inhomogeneous phase in the form of a chiral density wave is realized, but only for densities larger than 2.4ρ0, where ρ0 is the nuclear matter ground-state density
Wanted! Nuclear Data for Dark Matter Astrophysics
Astronomical observations from small galaxies to the largest scales in the universe can be consistently explained by the simple idea of dark matter. The nature of dark matter is however still unknown. Empirically it cannot be any of the known particles, and many theories postulate it as a new elementary particle. Searches for dark matter particles are under way: production at high-energy accelerators, direct detection through dark matter-nucleus scattering, indirect detection through cosmic rays, gamma rays, or effects on stars. Particle dark matter searches rely on observing an excess of events above background, and a lot of controversies have arisen over the origin of observed excesses. With the new high-quality cosmic ray measurements from the AMS-02 experiment, the major uncertainty in modeling cosmic ray fluxes is in the nuclear physics cross sections for spallation and fragmentation of cosmic rays off interstellar hydrogen and helium. The understanding of direct detection backgrounds is limited by poor knowledge of cosmic ray activation in detector materials, with order of magnitude differences between simulation codes. A scarcity of data on nucleon spin densities blurs the connection between dark matter theory and experiments. What is needed, ideally, are more and better measurements of spallation cross sections relevant to cosmic rays and cosmogenic activation, and data on the nucleon spin densities in nuclei
From QCD to nuclear matter saturation
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)
A variational theory of nuclear matter. III
Developments in a variational theory of nuclear matter for treating v6 homework potentials that include central, spin, isospin and tensor operators are reported. The central, spin, isospin and tensor correlations are parametrized by their range d, and the magnitudes of the non-central correlations. Integral equations are used to sum Fermi hypernetted chain, and single operator chain diagrams. All commutators required to evaluate the energy from the operator chain functions are treated exactly, and the energy is found to have a minimum with respect to variations in all parameters. Results of calculations with v6 models based on the Reid and Bethe-Johnson potentials are reported. A crude estimate of the effect of the spin-orbit potentials on nuclear matter binding energy indicates that it could be significant. (Auth.)
Nucleons interacting with excited nuclear matter
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)
A Separable Pairing Force in Nuclear Matter
TIAN Yuan; MA Zhong-Yu
2006-01-01
The method introduced by Duguet is adopted to derive a separable form of the pairing interaction in the 1 S0channel from a bare or an effective nucleon-nucleon (NN) interaction in nuclear matter. With this approach the separable pairing interaction reproduces the pairing properties provided by its corresponding NN interaction. In this work, separable forms of pairing interactions in the 1 S0 channel for the bare NN interaction, Bonn potential and the Gogny effective interaction are obtained. It is found that the separable force of the Gogny effective interaction in the 1 S0 channel has a clear link with the bare NN interaction. With such a simple separable form pairing properties provided by the Gogny force in nuclear matter can be reproduced.
Nuclear matter fourth-order symmetry energy in relativistic mean field models
Cai, Bao-Jun
2011-01-01
Within the nonlinear relativistic mean field model, we derive the analytical expression of the nuclear matter fourth-order symmetry energy $E_{4}(\\rho)$. Our results show that the value of $E_{4}(\\rho)$ at normal nuclear matter density $\\rho_{0}$ is generally less than 1 MeV, confirming the empirical parabolic approximation to the equation of state for asymmetric nuclear matter at $\\rho_{0}$. On the other hand, we find that the $E_{4}(\\rho)$ may become nonnegligible at high densities. Furthermore, the analytical form of the $E_{4}(\\rho)$ provides the possibility to study the higher-order effects on the isobaric incompressibility of asymmetric nuclear matter, i.e., $K_{\\mathrm{sat}}(\\delta)=K_{0}+K_{\\mathrm{{sat},2}}\\delta ^{2}+K_{\\mathrm{{sat},4}}\\delta ^{4}+\\mathcal{O}(\\delta ^{6})$ where $\\delta =(\\rho_{n}-\\rho_{p})/\\rho $ is the isospin asymmetry, and we find that the value of $K_{\\mathrm{{sat},4}}$ is generally comparable with that of the $K_{\\mathrm{{sat},2}}$. In addition, we study the effects of the $E...
Quartic isospin asymmetry energy of nuclear matter from chiral pion-nucleon dynamics
Kaiser, N
2015-01-01
Based on a chiral approach to nuclear matter, we calculate the quartic term in the expansion of the equation of state of isospin-asymmetric nuclear matter. The contributions to the quartic isospin asymmetry energy $A_4(k_f)$ arising from $1\\pi$-exchange and chiral $2\\pi$-exchange in nuclear matter are calculated analytically together with three-body terms involving virtual $\\Delta(1232)$-isobars. From these interaction terms one obtains at saturation density $\\rho_0 = 0.16\\,$fm$^{-3}$ the value $A_4(k_{f0})= 1.5\\,$MeV, more than three times as large as the kinetic energy part. Moreover, iterated $1\\pi$-exchange exhibits components for which the fourth derivative with the respect to the isospin asymmetry parameter $\\delta$ becomes singular at $\\delta =0$. The genuine presence of a non-analytical term $\\delta^4 \\ln|\\delta|$ in the expansion of the energy per particle of isospin-asymmetric nuclear matter is demonstrated by evaluating a s-wave contact interaction at second order.
Shock wave formation in hot nuclear matter
Assuming that nuclear matter can be treated as a perfect fluid, we study the propagation of perturbations in the baryon density at high temperature. The equation of state is derived from the non-linear Walecka model. The expansion of the Euler and continuity equations of relativistic hydrodynamics around equilibrium configurations lead to the breaking wave equation for the density perturbation. We solve it numerically for this perturbation and follow the propagation of the initial pulses. (author)
Nuclear matter with scalar-vector interactions
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
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
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.
Description of a nucleon in nuclear matter
The nonlinear cloudy bag model, CBM, is generalized to describe a nucleon in nuclear matter at various densities ρ and temperatures T. The influence of the nuclear medium on the bag-nucleon in the framework of CBM is due to the modification of the equation describing the CBM pion field π. These changes are accounted for in the CBM by including in the CBM lagrangian the pion polarization operator π(ρ,T). The free pion propagator D is replaced in a nuclear medium by D(ρ,T). The changing of the pion field π and propagator D leads via the CBM equations to the modification of the bag size R and quark momentum p, determined simultaneously from these equations, and then to modifications of other bag-nucleon characteristics: the total energy E, r.m.s. radii, magnetic moment μ, polarizability α and so on, which all are expressed as the expectation values of the corresponding operators in the bag-nucleon state. The quantity π(ρ,T) was studied in the works whose results are used in this investigation. The nucleon size R in the nuclear matter at normal density ρo and zero temperature decreases by 5% and the quarks momentum p also decreases, however, insignificantly, by 1-2%. On the other hand, the values of the r.m.s. radii increases by 15% for a proton and by 100% for a neutron. The author has also found that the polarizability of a nucleon in nuclear matter is roughly two times as much as in free space
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.
Nuclear dynamics of mass asymmetric systems at balance energy
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
Inhomogeneous phases of isospin-asymmetric matter in the Nambu-Jona-Lasinio model
We investigate the phase structure of strong-interaction matter within a two-flavor Nambu-Jona-Lasinio model. Earlier it has been shown for degenerate quark flavors that chiral symmetry-breaking phases with spatially modulated order-parameters can occur. We analyze the emergence of these inhomogeneous phases in isospin-asymmetric matter by extending the model through an additional isospin chemical potential, however restricting the order-parameter to be spatially modulated in only one dimension. It is found that for a non-vanishing isospin chemical potential the formation of inhomogeneous chiral symmetry-breaking phases is disfavored, when enforcing equal periodicities for the up and down quarks and neglecting charged pion condensation. If the periodicities of the quarks are not limited to be of the same magnitude, inhomogeneous chiral symmetry-breaking phases are found to be less sensitive to the additional pairing stress and can occur in a larger domain of the phase diagram. As an outlook we discuss possible extensions, like the addition of inhomogeneous charged pion condensation or color superconductivity.
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...
Elementary diagrams in nuclear and neutron matter
Variational calculations of nuclear and neutron matter are currently performed using a diagrammatic cluster expansion with the aid of nonlinear integral equations for evaluating expectation values. These are the Fermi hypernetted chain (FHNC) and single-operator chain (SOC) equations, which are a way of doing partial diagram summations to infinite order. A more complete summation can be made by adding elementary diagrams to the procedure. The simplest elementary diagrams appear at the four-body cluster level; there is one such E4 diagram in Bose systems, but 35 diagrams in Fermi systems, which gives a level of approximation called FHNC/4. We developed a novel technique for evaluating these diagrams, by computing and storing 6 three-point functions, Sxyz(r12, r13, r23), where xyz (= ccd, cce, ddd, dde, dee, or eee) denotes the exchange character at the vertices 1, 2, and 3. All 35 Fermi E4 diagrams can be constructed from these 6 functions and other two-point functions that are already calculated. The elementary diagrams are known to be important in some systems like liquid 3He. We expect them to be small in nuclear matter at normal density, but they might become significant at higher densities appropriate for neutron star calculations. This year we programmed the FHNC/4 contributions to the energy and tested them in a number of simple model cases, including liquid 3He and Bethe's homework problem. We get reasonable, but not exact agreement with earlier published work. In nuclear and neutron matter with the Argonne v14 interaction these contributions are indeed small corrections at normal density and grow to only 5-10 MeV/nucleon at 5 times normal density
Hadronization measurements in cold nuclear matter
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.
Mass shift of -meson in nuclear matter
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.
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.
History of the nuclear matter safety and control law
In this text we give the history of the law creation on the control and safety of nuclear matter. Initially based on the CEA regulation single owner of nuclear matter, the development of nuclear energy has conducted the French government to edict law in relation with IAEA and Euratom recommendations
Particle-hole states in nuclear matter
This work deals with the collective excitations in nuclear matter, from the point of view of the TDA approximation. Our calculations involved the construction of a Hamiltonian, expressed as a matrix in the space of particle-hole excitations with a given momentum transfer. We used in this Hamiltonian an average single nucleon potential, and (in some cases) an effective interaction obtained for the potential HEA in the relativistic Brueckner-Hartree Fock theory. The eigenvectors of the TDA-Hamiltonian were used to compute the strength of the collective response of nuclear matter to external probes. Our results, succinctly described in the last section, are summarized in a set of figures at the end of this monograph. The 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
Superfluid nuclear matter in BCS theory and beyond
CAO Li-Gang; U. Lombardo; P. Schuck
2009-01-01
Medium polarization effects are studied for 1S0 pairing in nuclear matter within BHF approach.The screening potential is calculated in the RPA limit, suitably renormalized to cure the low density mechanical instability of nuclear matter. The self-energy corrections are consistently included resulting in a strong depletion of the Fermi surface. The self-energy effects always lead to a quenching of the gap, whereas it is almost completely compensated by the anti-screening effect in nuclear matter.
Asymmetric dark matter in the Sun and diphoton excess at the LHC
Dev, P. S. Bhupal; Teresi, Daniele
2016-07-01
It has been recently pointed out that a momentum-dependent coupling of the asymmetric dark matter (ADM) with nucleons can explain the broad disagreement between helioseismological observables and the predictions of standard solar models. In this paper, we propose a minimal simplified ADM model consisting of a scalar and a pseudoscalar mediator, in addition to a Dirac fermionic DM, for generating such momentum-dependent interactions. Remarkably, the pseudoscalar with mass around 750 GeV can simultaneously explain the solar anomaly and the recent diphoton excess observed by both ATLAS and CMS experiments in the early √{s }=13 TeV LHC data. In this framework, the total width of the resonance is naturally large, as suggested by the ATLAS experiment, since the resonance mostly decays to the ADM pair. The model predicts the existence of a new light scalar in the GeV range, interacting with quarks, and observable dijet, monojet, and t t ¯ signatures for the 750 GeV resonance at the LHC.
Chiral Fermi liquid description of nuclear matter
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
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)
Quark distributions in nuclear matter and the EMC effect
Mineo, H.; Bentz, W.; Ishii, N.; A.W. Thomas; Yazaki, K.
2003-01-01
Quark light cone momentum distributions in nuclear matter and the structure function of a bound nucleon are investigated in the framework of the Nambu-Jona-Lasinio model. This framework describes the nucleon as a relativistic quark-diquark state, and the nuclear matter equation of state by using the mean field approximation. The scalar and vector mean fields in the nuclear medium couple to the quarks in the nucleon and their effect on the spin independent nuclear structure function is investi...
Phases of kinky holographic nuclear matter
Elliot-Ripley, Matthew; Zamaklar, Marija
2016-01-01
Holographic QCD at finite baryon number density and zero temperature is studied within the five-dimensional Sakai-Sugimoto model. We introduce a new approximation that models a smeared crystal of solitonic baryons by assuming spatial homogeneity to obtain an effective kink theory in the holographic direction. The kink theory correctly reproduces a first order phase transition to lightly bound nuclear matter. As the density is further increased the kink splits into a pair of half-kink constituents, providing a concrete realization of the previously suggested dyonic salt phase, where the bulk soliton splits into constituents at high density. The kink model also captures the phenomenon of baryonic popcorn, in which a first order phase transition generates an additional soliton layer in the holographic direction. We find that this popcorn transition takes place at a density below the dyonic salt phase, making the latter energetically unfavourable. However, the kink model predicts only one pop, rather than the seq...
Relativistic calculation of polarized nuclear matter
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)
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.
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.
On the thermal properties of nuclear matter with neutron excess
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
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)
Variational Monte Carlo Calculations of Energy per Particle Nuclear Matter
Manisa, K.
2004-01-01
In this paper, symmetrical nuclear matter has been investigated. Total, kinetic and potential energies per particle were obtained for nuclear matter by Variational Monte Carlo method. We have observed that the results are in good agreement with those obtained by various authors who used different potentials and techniques.
Self-interacting asymmetric dark matter coupled to a light massive dark photon
Dark matter (DM) with sizeable self-interactions mediated by a light species offers a compelling explanation of the observed galactic substructure; furthermore, the direct coupling between DM and a light particle contributes to the DM annihilation in the early universe. If the DM abundance is due to a dark particle-antiparticle asymmetry, the DM annihilation cross-section can be arbitrarily large, and the coupling of DM to the light species can be significant. We consider the case of asymmetric DM interacting via a light (but not necessarily massless) Abelian gauge vector boson, a dark photon. In the massless dark photon limit, gauge invariance mandates that DM be multicomponent, consisting of positive and negative dark ions of different species which partially bind in neutral dark atoms. We argue that a similar conclusion holds for light dark photons; in particular, we establish that the multi-component and atomic character of DM persists in much of the parameter space where the dark photon is sufficiently light to mediate sizeable DM self-interactions. We discuss the cosmological sequence of events in this scenario, including the dark asymmetry generation, the freeze-out of annihilations, the dark recombination and the phase transition which gives mass to the dark photon. We estimate the effect of self-interactions in DM haloes, taking into account this cosmological history. We place constraints based on the observed ellipticity of large haloes, and identify the regimes where DM self-scattering can affect the dynamics of smaller haloes, bringing theory in better agreement with observations. Moreover, we estimate the cosmological abundance of dark photons in various regimes, and derive pertinent bounds
Dark Matter Particle Spectroscopy at the LHC: Generalizing M(T2) to Asymmetric Event Topologies
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.
Nuclear stopping power in warm and hot dense matter
Faussurier, Gerald; Blancard, Christophe [CEA, DAM, DIF, F-91 297 Arpajon (France); Gauthier, Maxence [CEA, DAM, DIF, F-91 297 Arpajon (France); LULI, Ecole Polytechnique, CNRS, CEA, UPMC, Route de Saclay, 91128 Palaiseau (France)
2013-01-15
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.
Partial restoration of chiral symmetry in nuclear matter
Recent work of Cohen, Furnstahl, and Griegel has advanced our understanding of the behavior of quark and gluon condensates in nuclear matter. We make use of their analysis to discuss the role of chiral condensates as they appear in relativistic Brueckner-Hartree-Fock theory. We find some support for assumptions we used to discuss the properties of nuclear matter in our earlier work. We also find that a rather consistent picture emerges from these studies, when we relate the parameters of the boson-exchange model of nuclear forces to an underlying field-theoretic description of nuclear matter
A fermionic molecular dynamics technique to model nuclear matter
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)
Bredtmann, Timm; Manz, Jörn; Zhao, Jian-Ming
2016-05-19
The quantum theory of concerted electronic and nuclear fluxes (CENFs) during coherent periodic tunnelling from reactants (R) to products (P) and back to R in molecules with asymmetric double-well potentials is developed. The results are deduced from the solution of the time-dependent Schrödinger equation as a coherent superposition of two eigenstates; here, these are the two states of the lowest tunnelling doublet. This allows the periodic time evolutions of the resulting electronic and nuclear probability densities (EPDs and NPDs) as well as the CENFs to be expressed in terms of simple sinusodial functions. These analytical results reveal various phenomena during coherent tunnelling in asymmetric double-well potentials, e.g., all EPDs and NPDs as well as all CENFs are synchronous. Distortion of the symmetric reference to a system with an asymmetric double-well potential breaks the spatial symmetry of the EPDs and NPDs, but, surprisingly, the symmetry of the CENFs is conserved. Exemplary application to the Cope rearrangement of semibullvalene shows that tunnelling of the ideal symmetric system can be suppressed by asymmetries induced by rather small external electric fields. The amplitude for the half tunnelling, half nontunnelling border is as low as 0.218 × 10(-8) V/cm. At the same time, the delocalized eigenstates of the symmetric reference, which can be regarded as Schrödinger's cat-type states representing R and P with equal probabilities, get localized at one or the other minima of the asymmetric double-well potential, representing either R or P. PMID:26799383
Neutron-proton mass difference in nuclear matter
Meissner, U.G.; Rakhimov, A. M.; Wirzba, A.; Yakhshiev, U.T.
2006-01-01
Isospin-breaking effects in nuclear matter are 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. The approach predicts that the neutron-proton mass difference decreases in isospin-symmetric nuclear matter but by a very small amount only.
Relativistic Chiral Theory of Nuclear Matter and QCD Constraints
Chanfray, G.; Ericson, M.
2009-01-01
Talk given by G. Chanfray at PANIC 08, Eilat (Israel), november 10-14, 2008 We present a relativistic chiral theory of nuclear matter which includes the effect of confinement. Nuclear binding is obtained with a chiral invariant scalar background field associated with the radial fluctuations of the chiral condensate Nuclear matter stability is ensured once the scalar response of the nucleon depending on the quark confinement mechanism is properly incorporated. All the parameters are fixed o...
Strangeness and charm in nuclear matter
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.
QMD application of sub-saturated nuclear matter
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
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.)
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....
Kaons in nuclear matter; Kaonen in Kernmaterie
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.
Track theory and nuclear photographic emulsions for Dark Matter searches
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
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 r...
Studies for the equation of state in the isospin asymmetrical nuclear interactions
In order to determine the equation of state in the isospin asymmetrical nuclear interactions, we have found the observables for extracting the information of them within the isospin-dependent quantum molecular dynamics in recent years. The several sensitive probes for extracting the information of the in-medium nucleon–nucleon cross section and the symmetry potential have found; meanwhile, their mechanisms are investigated in more details. The main point in this paper gives the summary for above probes and their outlook in the future. (author)
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.
Pion Effect of Nuclear Matter in a Chiral Sigma Model
HU Jin-niu; Y.Ogawa; H.Toki; A.Hosaka; SHEN Hong
2009-01-01
We develop a new framework for the study of the nuclear matter based on the linear sigma model.We introduce a completely new viewpoint on the treatment of the nuclear matter with the inclusion of the pion.We extend the relativistic chiral mean field model by using the similar method in the tensor optimized shell model.We also regulate the pion-nucleon interaction by considering the form-factor and short range repulsion effects.We obtain the equation of state of nuclear matter and study the importance of the pion effect.
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.)
Reflection on penal policy in nuclear matters
This document expresses ethical reflexions as far as nuclear energy development is concerned. The potential diversion of the peaceful use of nuclear energy results in the necessity of a criminal policy which would control the nuclear regulations. For each potential nuclear infringement, systems of laws are established either to prevent damages or to penalize them. (TEC)
K meson-nucleus interactions: strangeness and nuclear matter
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
Vector Mesons and Baryon Resonances in Nuclear Matter
Post, M.; Mosel, U.
2001-01-01
We calculate the effect of many-body interactions in nuclear matter on the spectral function of $\\rho$ and $\\omega$ meson. In particular, we focus on the role played by baryon resonances in this context.
Aymard, François; Gulminelli, Francesca; Margueron, Jérôme
2016-08-01
We have recently addressed the problem of the determination of the nuclear surface energy for symmetric nuclei in the framework of the extended Thomas-Fermi (ETF) approximation using Skyrme functionals. We presently extend this formalism to the case of asymmetric nuclei and the question of the surface symmetry energy. We propose an approximate expression for the diffuseness and the surface energy. These quantities are analytically related to the parameters of the energy functional. In particular, the influence of the different equation of state parameters can be explicitly quantified. Detailed analyses of the different energy components (local/non-local, isoscalar/isovector, surface/curvature and higher order) are also performed. Our analytical solution of the ETF integral improves previous models and leads to a precision of better than 200 keV per nucleon in the determination of the nuclear binding energy for dripline nuclei.
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.
Investigations of instabilities in nuclear matter in stochastic relativistic models
Ayik, S., E-mail: ayik@tntech.edu [Physics Department, Tennessee Technological University, Cookeville, TN 38505 (United States); Yilmaz, O.; Acar, F.; Danisman, B. [Physics Department, Middle East Technical University, 06531 Ankara (Turkey); Er, N. [Physics Department, Abant Izzet Baysal University, Bolu (Turkey); Gokalp, A. [Physics Department, Middle East Technical University, 06531 Ankara (Turkey)
2011-06-01
The spinodal instabilities for symmetric nuclear matter at finite temperature are studied within different relativistic mean-field models in the semi-classical approximation and the relativistic results are compared with Skyrme type non-relativistic calculations. Qualitatively similar results appear in the unstable response of the system in both non-relativistic and relativistic descriptions. Furthermore, the early growth of baryon, scalar and current density correlation functions are calculated for hot symmetric nuclear matter.
Relativistic and non-relativistic studies of nuclear matter
Banerjee, M. K.; Tjon, J. A.
2001-01-01
Recently we showed that while the tensor force plays an important role in nuclear matter saturation in non-relativistic studies, it does not do so in relativistic studies. The reason behind this is the role of $M^*$, the sum of nucleon mass and its attractive self-energy in nuclear matter. Yet nonrelativistic calculations at a certain level of approximation are far less difficult than comparative relativistic calculation. Naturally the question arises if one can modify a nonrelativistic metho...
Many-body theory of nuclear and neutron star matter
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.)
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)
Nuclear incompressibility: from finite nuclei to nuclear matter
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
The role of meson dynamics in nuclear matter saturation
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)
Inex - NEA's programme on nuclear emergency matters
The OECD Nuclear Energy Agency has a long tradition of expertise in the area of nuclear emergency policy, planing, preparedness and management. A major mechanism for the latter has been the development, preparation and organization of the International Nuclear Exercise (INEX) series. These international exercises have provided a valuable and unique forum for testing and verifying existing as well as new arrangements and concepts for international nuclear emergency management. This document presents the different INEX over the last 15 years and their contribution in the nuclear emergency management in an international context. (A.L.B.)
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.
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...
From nuclear matter to finite nuclei. Pt. 1
In this paper we develop various parametrizations of the nuclear matter Dirac-Brueckner G-matrix, which are suitable for application in relativistic Hartree-Fock calculations of finite nuclei. The relativistic one boson exchange model forms the basis of this effective interaction. The parameters, which are obtained from a least squares fit, explicitly depend on the density. We also require the interaction to reproduce the self-energies and the binding energy of nuclear matter very accurately. It is shown that for densities up to 1.5 times normal nuclear density the saturation curve virtually coincides with the original Dirac-Brueckner result and yields a good prediction of the nuclear matter compressibility. (orig.)
The Effects of Correlations on Neutrino Opacities in Nuclear Matter
Burrows, Adam; Sawyer, R. F.
1998-01-01
Including nucleon-nucleon correlations due to both Fermi statistics and nuclear forces, we have developed a general formalism for calculating the neutral-current neutrino-nucleon opacities in nuclear matter. We derive corrections to the dynamic structure factors due to both density and spin correlations and find that neutrino-nucleon cross sections are suppressed by large factors around and above nuclear density. In addition, we find that the spectrum of energy transfers in neutrino scatterin...
The Relativistic Dirac-Brueckner Approach to Nuclear Matter
Fuchs, Christian
2003-01-01
An overview on the relativistic Dirac-Brueckner approach to the nuclear many-body problem is given. Different approximation schemes are discussed, with particular emphasis on the nuclear self-energy and the saturation mechanism of nuclear matter. I will further discuss extensions of the standard approach, amongst other things the inclusion of non-nucleonic degrees of freedom, many-body forces and finally compare relativistic and non-relativistic approaches.
Simulations of cold nuclear matter at sub-saturation densities
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
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.
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
Martinik, Tomas; Henzl, Vladimir; Grape, Sophie; Svärd, Staffan Jacobsson; Jansson, Peter; Swinhoe, Martyn T.; Tobin, Stephen J.
2015-07-01
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
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
Equation of state for β-stable hot nuclear matter
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
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.)
Pion absorption in excited nuclear matter
The target dependence and azimuthal correlations of protons and pions are investigated for pA reactions at 4.9, 60 and 200 GeV. The experimental observations can be understood qualitatively under the assumption that pions are absorbed in excited target spectator matter. (orig.)
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...
Updated constraints on velocity and momentum-dependent asymmetric dark matter
Vincent, Aaron C.; Scott, Pat; 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 abun...