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...
δ Meson Effects on Asymmetric Nuclear Matter
Liu, B.; di Toro, M.; Greco, V.
The impact of a δ meson field (the scalar-isovector channel) on asymmetric nuclear matter is studied within relativistic mean-field (RMF) models with both constant and density dependent (DD) nucleon-meson couplings. The Equation of State (EOS) for asymmetric nuclear matter and the neutron star properties by the different models are compared. We find that the δ-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 influencing the stability of the neutron stars. A broader analysis of possible δ-field effects is achieved considering also density dependent nucleon-meson coupling. A remarkable effect on the relation between mass and radius for the neutron stars is seen, showing a significant reduction of the radius along with a moderate mass reduction due to the increase of the effective δ coupling in high density regions.
Asymmetric nuclear matter equation of state
Energy Technology Data Exchange (ETDEWEB)
Bombaci, I.; Lombardo, U. (Dipartimento di Fisica, Universita di Catania, Corso Italia 57, Catania (Italy) Istituto Nazionale di Fisica Nucleare, Sezione di Catania, Corso Italia 57, I-95129 Catania (Italy))
1991-11-01
Systematic calculations of asymmetric nuclear matter have been performed in the framework of the Brueckner-Bethe-Goldstone approach in a wide range of both density and asymmetry parameter. The empirical parabolic law fulfilled by the binding energy per nucleon is confirmed by the present results in all the range of the asymmetry parameter values. The predominant role of the {sup 3}{ital S}{sub 1-}{sup 3}{ital D}{sub 1} component of the {ital NN} interaction is elucidated. A linear variation of the proton and neutron single-particle potentials is found as increasing the neutron excess; a deviation from the phenomenological potentials occurs for highly asymmetric matter as an effect of the self-consistency. The present calculations of the incompressibility predict a strong softening of the equation of state going from symmetric to asymmetric nuclear matter. The proton fraction in equilibrium with neutron matter has been determined from the beta-stability condition and its relevance to the superfluidity of neutron stars has been investigated.
Phase transitions in warm, asymmetric nuclear matter
International Nuclear Information System (INIS)
A relativistic mean-field model of nuclear matter with arbitrary proton fraction is studied at finite temperature. An analysis is performed of the liquid-gas phase transition in a system with two conserved charges (baryon number and isospin) using the stability conditions on the free energy, the conservation laws, and Gibbs' criteria for phase equilibrium. For a binary system with two phases, the coexistence surface (binodal) is two dimensional. The Maxwell construction through the phase-separation region is discussed, and it is shown that the stable configuration can be determined uniquely at every density. Moreover, because of the greater dimensionality of the binodal surface, the liquid-gas phase transition is continuous (second order by Ehrenfest's definition), rather than discontinuous (first order), as in familiar one-component systems. Using a mean-field equation of state calibrated to the properties of nuclear matter and finite nuclei, various phase-separation scenarios are considered. The model is then applied to the liquid-gas phase transition that may occur in the warm, dilute matter produced in energetic heavy-ion collisions. In asymmetric matter, instabilities that produce a liquid-gas phase separation arise from fluctuations in the proton concentration (chemical instability), rather than from fluctuations in the baryon density (mechanical instability)
Pseudo-Goldstone modes in isospin-asymmetric nuclear matter
Energy Technology Data Exchange (ETDEWEB)
Cohen, T.D. [Washington Univ., Seattle, WA (United States). Dept. of Physics; Broniowski, W. [Institute of Nuclear Physics, Cracow (Poland)
1994-12-01
We analyze the chiral limit in dense isoptin-asymmetric nuclear matter. It is shown that the pseudo-Goldstone modes in this system are qualitatively different from the case of isospin-symmetric matter. (author). 20 refs.
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...
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.
Application of density dependent parametrization models to asymmetric nuclear matter
International Nuclear Information System (INIS)
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
Institute of Scientific and Technical Information of China (English)
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.
Pairing effects on spinodal decomposition of asymmetric nuclear matter
Directory of Open Access Journals (Sweden)
Burrello S.
2015-01-01
Full Text Available We present an analysis framed in the general context of two-component fermionic systems subjected to pairing correlations. The study is conducted for unstable asymmetric nuclear matter at low temperature, along the clusterization process driven by spinodal instabilities. It is shown that, especially around the transition temperature from the superfluid to the normal phase, pairing correlations may have non-negligible effects on the isotopic features of the clusterized low-density matter, which could be of interest also in the astrophysical context.
DBHF Method for Asymmetric Nuclear Matter and Finite Nuclei
Institute of Scientific and Technical Information of China (English)
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
International Nuclear Information System (INIS)
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
Institute of Scientific and Technical Information of China (English)
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
Institute of Scientific and Technical Information of China (English)
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.
A New Decomposition Approach of Dirac Brueckner Hartree-Fock G Matrix for Asymmetric Nuclear Matter
Institute of Scientific and Technical Information of China (English)
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.
Symmetry energy parameters in pion-dressed asymmetric nuclear matter
International Nuclear Information System (INIS)
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
Equation of state for isospin asymmetric nuclear matter using Lane potential
Basu, D N; Samanta, C
2006-01-01
A variational method of obtaining equation of state (EOS) for symmetric nuclear matter from a density dependent M3Y interaction supplemented by a zero-range potential is described. The energy per nucleon is minimized to obtain the ground state of symmetric nuclear matter. The saturation energy per nucleon used for nuclear matter calculations is determined from the co-efficient of the volume term of Bethe-Weizs\\"acker mass formula which is evaluated by fitting the recent experimental and estimated atomic mass excesses from Audi-Wapstra-Thibault atomic mass table by minimizing the mean square deviation. The constants of density dependence of the effective interaction are obtained by reproducing the saturation energy per nucleon and the saturation density of spin and isospin symmetric cold infinite nuclear matter. The EOS of symmetric nuclear matter, thus obtained, provide reasonably good estimate of nuclear incompressibility. Once the consants of density dependence are determined, EOS for asymmetric nuclear mat...
Critical phenomena of asymmetric nuclear matter in the extended Zimanyi-Moszkowski model
Miyazaki, K
2005-01-01
We have studied the liquid-gas phase transition of warm asymmetric nuclear matter in the extended Zimanyi-Moszkowski model. The three sets of the isovector-meson coupling constants are used. It is found that the critical temperature depends only on the difference of the symmetry energy but not on the differences of each isovector coupling constant. We treat the asymmetric nuclear matter as one-component system and employ the Maxwell construction so as to calculate the liquid-gas phase coexistence curve. The derived critical exponents depend on neither the symmetry energy nor the asymmetry of the system. Their values beta=0.33 and gamma=1.21 agree with the empirical values derived from the recent multifragmentation reactions. Consequently, we have confirmed the universality of the critical phenomena in the liquid-gas phase transition of nuclear matter.
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...
A new mathematical model for the equation of state of an asymmetric infinite nuclear matter
Zoghi-Foumani, N.; Shojaei, M. R.
2016-04-01
In this paper, the average energy variation with respect to the density of a system of nucleons is studied. A new formula is presented for the nuclear equation of state. This formula is related to an infinite system of protons and neutrons with relatively small thermal excitations. It is shown that the proposed formulation for the nuclear equation of state reproduces the results obtained in the Skyrme-Hartree-Fock (SHF) and Relativistic Mean-Field (RMF) models of nuclear matter. It should be realized that the consistency of the obtained results for nuclear matter with the predictions of well-known SHF and RMF models for symmetric and asymmetric system of nucleons indicates the reliability of this formulation for different types of nuclear matter in large scales such as neutron stars.
Neutron Skin and Equation of State in Asymmetric Nuclear Matter
Yoshida, Satoshi; Sagawa, Hiroyuki
2005-12-01
Neutron skin thickness of stable and unstable nuclei are studied by using Skyrme Hartree-Fock (SHF) models and relativistic mean field (RMF) models in relation with the pressure of EOS in neutron matter. We found a clear linear correlation between the neutron skin sizes in heavy nuclei, 132Sn and 208Pb and the pressure of neutron matter in both SHF and RMF, while the correlation is weak in unstable nuclei 32Mg and 44Ar.
Non-congruence of liquid-gas phase transition of asymmetric nuclear matter
Maruyama, Toshiki
2012-01-01
We first explore the liquid-gas mixed phase in a bulk calculation, where two phases coexist without the geometrical structures. In the case of symmetric nuclear matter, the system behaves congruently, and the Maxwell construction becomes relevant. For asymmetric nuclear matter, on the other hand, the phase equilibrium is no more attained by the Maxwell construction since the liquid and gas phases are non-congruent; the particle fractions become completely different with each other. One of the origins of such non-congruence is attributed to the large symmetry energy. Subsequently we explore the charge-neutral nuclear matter with electrons by fully applying the Gibbs conditions to figure out the geometrical (pasta) structures in the liquid-gas mixed phase. We emphasize the effects of the surface tension and the Coulomb interaction on the pasta structures. We also discuss the thermal effects on the pasta structures.
Single particle potentials of asymmetric nuclear matter in different spin-isospin channels
Institute of Scientific and Technical Information of China (English)
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.
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.
Study of various charged p-meson masses in asymmetric nuclear matter
Institute of Scientific and Technical Information of China (English)
YAO Hai-Bo; WU Shi-Shu
2009-01-01
We study the effective masses of p-mesons for different charged states in asymmetric nuclear matter (ANM) using the Quantum Hadrodynamics II model.The closed form analytical results are presented for the effective masses of p-mesons.We have shown that the different charged p-mesons have mass splitting similar to various charged pions.The effect of the Dirac sea is also examined, and it is found that this effect is very important and leads to a reduction of the different charged p-meson masses in ANM.
Energy Technology Data Exchange (ETDEWEB)
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.)
Asymmetric dense matter in holographic QCD
Directory of Open Access Journals (Sweden)
Shin Ik Jae
2012-02-01
Full Text Available We study asymmetric dense matter in holographic QCD.We construct asymmetric dense matter by considering two quark flavor branes with dierent quark masses in a D4/D6/D6 model. To calculate the symmetry energy in nuclear matter, we consider two quarks with equal masses and observe that the symmetry energy increases with the total charge showing the stiff dependence. This behavior is universal in the sense that the result is independent of parameters in the model. We also study strange (or hyperon matter with one light and one intermediate mass quarks. In addition to the vacuum properties of asymmetric matter, we calculate meson masses in asymmetric dense matter and discuss our results in the light of in-medium kaon masses.
Neutron skin thickness and equation of state in asymmetric nuclear matter
Yoshida, Satoshi; Sagawa, Hiroyuki
2004-02-01
The neutron skin thickness of stable and unstable nuclei is studied in Skyrme Hartree-Fock (SHF) and relativistic mean field (RMF) models to investigate the relation between the pressure and the equation of state in neutron matter. We found a clear linear correlation between the neutron skin thickness in heavy nuclei 132 Sn and 208 Pb and the pressure of neutron matter in both SHF and RMF models, while the correlation is weak in the unstable nuclei 32 Mg and 44 Ar . Relations between the neutron skin thickness and other nuclear matter properties such as the symmetry energy coefficients and the nuclear incompressibility are discussed.
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.
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; 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...
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.
Institute of Scientific and Technical Information of China (English)
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.
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.
Sammarruca, Francesca
2013-01-01
After reviewing our microscopic approach to nuclear and neutron-rich matter, we focus on how nucleon-nucleon scattering is impacted by the presence of a dense hadronic medium, with special emphasis on the case where neutron and proton densities are different. We discuss in detail medium and isospin asymmetry effects on the total elastic cross section and the mean free path of a neutron or a proton in isospin-asymmetric nuclear matter. We point out that in-medium cross sections play an important role in heavy-ion simulations aimed at extracting constraints on the symmetry potential. We argue that medium and isospin dependence of microscopic cross sections are the results of a complex balance among various effects, and cannot be simulated with a simple phenomenological model.
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.
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
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
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.
Asymmetric Dark Matter and Effective Operators
Buckley, Matthew R
2011-01-01
In order to annihilate in the early Universe to levels well below the measured dark matter density, asymmetric dark matter must possess large couplings to the Standard Model. In this paper, we consider effective operators which allow asymmetric dark matter to annihilate into quarks. In addition to a bound from requiring sufficient annihilation, the energy scale of such operators can be constrained by limits from direct detection and monojet searches at colliders. We show that the allowed parameter space for these operators is highly constrained, leading to non-trivial requirements that any model of asymmetric dark matter must satisfy.
Asymmetric dark matter in braneworld cosmology
Energy Technology Data Exchange (ETDEWEB)
Meehan, Michael T.; Whittingham, Ian B., E-mail: Michael.Meehan@my.jcu.edu.au, E-mail: Ian.Whittingham@jcu.edu.au [School of Engineering and Physical Sciences, James Cook University, Townsville, 4811 Australia (Australia)
2014-06-01
We investigate the effect of a braneworld expansion era on the relic density of asymmetric dark matter. We find that the enhanced expansion rate in the early universe predicted by the Randall-Sundrum II (RSII) model leads to earlier particle freeze-out and an enhanced relic density. This effect has been observed previously by Okada and Seto (2004) for symmetric dark matter models and here we extend their results to the case of asymmetric dark matter. We also discuss the enhanced asymmetric annihilation rate in the braneworld scenario and its implications for indirect detection experiments.
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 ...
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.
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...
DAMA annual modulation effect and asymmetric mirror matter
Energy Technology Data Exchange (ETDEWEB)
Addazi, A.; Berezhiani, Z. [Universita di L' Aquila, Dipartimento di Scienze Fisiche e Chimiche, Coppito, AQ (Italy); INFN, Laboratori Nazionali del Gran Sasso, Assergi, AQ (Italy); Bernabei, R.; Belli, P. [Universita di Roma ' ' Tor Vergata' ' , Dipartimento di Fisica, Rome (Italy); INFN, Tor Vergata, Rome (Italy); Cappella, F.; Cerulli, R. [INFN, Laboratori Nazionali del Gran Sasso, Assergi, AQ (Italy); Incicchitti, A. [Universita di Roma ' ' La Sapienza' ' , Roma, Dipartimento di Fisica, Rome (Italy); INFN, Roma (Italy)
2015-08-15
The long-standing model-independent annual modulation effect measured by DAMA Collaboration is examined in the context of asymmetric mirror dark matter, assuming that dark atoms interact with target nuclei in the detector via kinetic mixing between mirror and ordinary photons, both being massless. The relevant ranges for the kinetic mixing parameter are obtained taking into account various existing uncertainties in nuclear and particle physics quantities as well as characteristic density and velocity distributions of dark matter in different halo models. (orig.)
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 ...
International Nuclear Information System (INIS)
It is stated that at the Workshop on Nuclear and Dense Matter held at the University of Illinois in May 1977 significant progress was reported that largely resolves many of the questions raised in this journal Vol. 6, p.149, 1976. These include perturbative versus variational methods as applied to nuclear matter, exact solutions for bosons, what is known as the fermion 'homework problem', and various other considerations regarding nuclear matter, including the use of variational methods as opposed to perturbation theory. (15 references) (U.K.)
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 ...
Charge Asymmetric Cosmic Rays as a probe of Flavor Violating Asymmetric Dark Matter
DEFF Research Database (Denmark)
Masina, Isabella; Sannino, Francesco
2011-01-01
The recently introduced cosmic sum rules combine the data from PAMELA and Fermi-LAT cosmic ray experiments in a way that permits to neatly investigate whether the experimentally observed lepton excesses violate charge symmetry. One can in a simple way determine universal properties of the unknown...... component of the cosmic rays. Here we attribute a potential charge asymmetry to the dark sector. In particular we provide models of asymmetric dark matter able to produce charge asymmetric cosmic rays. We consider spin zero, spin one and spin one-half decaying dark matter candidates. We show that lepton...... flavor violation and asymmetric dark matter are both required to have a charge asymmetry in the cosmic ray lepton excesses. Therefore, an experimental evidence of charge asymmetry in the cosmic ray lepton excesses implies that dark matter is asymmetric....
Abundance of Asymmetric Dark Matter in Brane World Cosmology
Abdusattar, Haximjan; Iminniyaz, Hoernisa
2016-09-01
Relic abundance of asymmetric Dark Matter particles in brane world cosmological scenario is investigated in this article. Hubble expansion rate is enhanced in brane world cosmology and it affects the relic abundance of asymmetric Dark Matter particles. We analyze how the relic abundance of asymmetric Dark Matter is changed in this model. We show that in such kind of nonstandard cosmological scenario, indirect detection of asymmetric Dark Matter is possible if the cross section is small enough which let the anti-particle abundance kept in the same amount with the particle. We show the indirect detection signal constraints can be used to such model only when the cross section and the 5-dimensional Planck mass scale are in appropriate values. Supported by the National Natural Science Foundation of China under Grant No. 11365022
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.
Dorso, C O; Nichols, J I; López, J A
2012-01-01
We study the behavior of cold nuclear matter near saturation density (\\rho 0) and very low temperature using classical molecular dynamics. We used three different (classical) nuclear interaction models that yield `medium' or `stiff' compressibilities. For high densities and for every model the ground state is a classical crystalline solid, but each one with a different structure. At subsaturation densities, we found that for every model the transition from uniform (crystal) to non-uniform matter occurs at \\rho ~ 0.12 fm^(-3) = 0.75 \\rho 0. Surprisingly, at the non-uniform phase, the three models produce `pasta-like' structures as those allegedly present in neutron star matter but without the long-range Coulomb interaction and with different length scales.
Functional renormalization group studies of nuclear and neutron matter
Drews, Matthias
2016-01-01
Functional renormalization group (FRG) methods applied to calculations of isospin-symmetric and asymmetric nuclear matter as well as neutron matter are reviewed. The approach is based on a chiral Lagrangian expressed in terms of nucleon and meson degrees of freedom as appropriate for the hadronic phase of QCD with spontaneously broken chiral symmetry. Fluctuations beyond mean-field approximation are treated solving Wetterich's FRG flow equations. Nuclear thermodynamics and the nuclear liquid-gas phase transition are investigated in detail, both in symmetric matter and as a function of the proton fraction in asymmetric matter. The equations of state at zero temperature of symmetric nuclear matter and pure neutron matter are found to be in good agreement with advanced ab-initio many-body computations. Contacts with perturbative many-body approaches (in-medium chiral perturbation theory) are discussed. As an interesting test case, the density dependence of the pion mass in the medium is investigated. The questio...
Asymmetric Dark Matter Models and the LHC Diphoton Excess
DEFF Research Database (Denmark)
Frandsen, Mads T.; Shoemaker, Ian M.
2016-01-01
The existence of dark matter (DM) and the origin of the baryon asymmetry are persistent indications that the SM is incomplete. More recently, the ATLAS and CMS experiments have observed an excess of diphoton events with invariant mass of about 750 GeV. One interpretation of this excess is decays...... have for models of asymmetric DM that attempt to account for the similarity of the dark and visible matter abundances....
Continuous Flavor Symmetries and the Stability of Asymmetric Dark Matter
Bishara, Fady
2014-01-01
Generically, the asymmetric interactions in asymmetric dark matter (ADM) models lead to decaying DM. We show that, for ADM that carries nonzero baryon number, the continuous flavor symmetries that generate the flavor structure in the quark sector also imply a looser lower bound on the mass scale of the asymmetric mediators between the dark and visible sectors. The mediators for $B=2$ ADM that can produce a signal in the future indirect dark matter searches can thus also be searched for at the LHC. For two examples of the mediator models, with either the MFV or Froggatt-Nielsen flavor breaking pattern, we derive the FCNC constraints and discuss the search strategies at the LHC.
International Nuclear Information System (INIS)
The subject of the doctoral thesis is examination of the properties of kaons in nuclear matter. A specific method is explained that has been developed for the scientific objectives of the thesis and permits description of the kaon-nucleon interactions and kaon-nucleon scattering in a vacuum. The main challenge involved was to find approaches that would enable application of the derived relations out of the kaon mass shell, connected with the second objective, namely to possibly find methods which are independent of models. The way chosen to achieve this goal relied on application of reduction formulas as well as current algebra relations and the PCAC hypothesis. (orig./CB)
Asymmetric dark matter and the Sun
DEFF Research Database (Denmark)
Frandsen, Mads Toudal; Sarkar, Subir
2010-01-01
Cold dark matter particles with an intrinsic matter-antimatter asymmetry do not annihilate after gravitational capture by the Sun and can affect its interior structure. The rate of capture is exponentially enhanced when such particles have self-interactions of the right order to explain structure...... formation on galactic scales. A `dark baryon' of mass 5 GeV is a natural candidate and has the required relic abundance if its asymmetry is similar to that of ordinary baryons. We show that such particles can solve the `solar composition problem'. The predicted small decrease in the low energy neutrino...
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.
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 ...
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...
Gamma ray constraints on flavor violating asymmetric dark matter
DEFF Research Database (Denmark)
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....
Nuclear matter and electron scattering
Energy Technology Data Exchange (ETDEWEB)
Sick, I. [Dept. fuer Physik und Astronomie, Univ. Basel (Switzerland)
1998-06-01
We show that inclusive electron scattering at large momentum transfer allows a measurement of short-range properties of nuclear matter. This provides a very valuable constraint in selecting the calculations appropriate for predicting nuclear matter properties at the densities of astrophysical interest. (orig.)
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.
Decaying Asymmetric Dark Matter Relaxes the AMS-Fermi Tension
Feng, Lei
2013-01-01
The first result of AMS-02 confirms the positron fraction excess observed by PAMELA, but in the dark matter (DM) interpretation, its softer spectrum brings a tension between AMS-02 and Fermi-LAT, which reported an excess of the electron plus positron flux. In this work we point out that the asymmetric cosmic ray from asymmetric dark matter (ADM) decay relaxes the tension, and find that at the two-body decay level a bosonic ADM around 2.4 TeV and decaying to\\mu^-\\tau^+ can significantly improve the fits. Based on the R-parity-violating supersymmetry with operators LLE^c, we propose a minimal model to realize that ADM scenario: Introducing a pair of singlets (X,\\bar X) and coupling them to the visible sector via LH_uX, we then obtain a leptonic decaying ADM with TeV-scale mass.
Asymmetric capture of Dirac dark matter by the Sun
International Nuclear Information System (INIS)
Current problems with the solar model may be alleviated if a significant amount of dark matter from the galactic halo is captured in the Sun. We discuss the capture process in the case where the dark matter is a Dirac fermion and the background halo consists of equal amounts of dark matter and anti-dark matter. By considering the case where dark matter and anti-dark matter have different cross sections on solar nuclei as well as the case where the capture process is considered to be a Poisson process, we find that a significant asymmetry between the captured dark particles and anti-particles is possible even for an annihilation cross section in the range expected for thermal relic dark matter. Since the captured number of particles are competitive with asymmetric dark matter models in a large range of parameter space, one may expect solar physics to be altered by the capture of Dirac dark matter. It is thus possible that solutions to the solar composition problem may be searched for in these type of models
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
Constraining Asymmetric Dark Matter through observations of compact stars
DEFF Research Database (Denmark)
Kouvaris, Christoforos; Tinyakov, Peter
2011-01-01
We put constraints on asymmetric dark matter candidates with spin-dependent interactions based on the simple existence of white dwarfs and neutron stars in globular clusters. For a wide range of the parameters (WIMP mass and WIMP-nucleon cross section), WIMPs can be trapped in progenitors in large...... numbers and once the original star collapses to a white dwarf or a neutron star, these WIMPs might self-gravitate and eventually collapse forming a mini-black hole that eventually destroys the star. We impose constraints competitive to direct dark matter search experiments, for WIMPs with masses down...
Propagation of neutrinos in nuclear matter
International Nuclear Information System (INIS)
We study the elementary interactions between neutrinos and dense matter in a proto-neutron star. Equations of state obtained with different nuclear effective interactions (Skyrme, Gogny, Relativistic Lagrangians) are first discussed. Then, we characterize their stability in spin and isospin. We derive magnetic susceptibilities for all isospin asymmetry values as a function of Landau parameters Gππ'0 (where π, π' = proton or neutron). From this work, we select a parametrization for each of the 3 effective forces: Sly230b,D1P,NL3. We calculate the pure neutron matter and asymmetric nuclear matter response functions with and without charge exchange, describing nuclear correlations in both approaches: non-relativistic (Hartree-Fock with Skyrme forces, then complete RPA) and relativistic (in the Hartree approximation). At the end, we calculate neutrino mean free paths neutral current and charged current reactions. Comparisons between relativistic and non-relativistic approaches allow us to identify relativistic effects in nuclear matter at densities as low as twice the saturation density. RPA correlations make the medium more transparent to neutrinos compared to free Fermi gas. The importance of the effective mass in mean free path calculations is also shown. (author)
Covariant density functional theory for nuclear matter
Energy Technology Data Exchange (ETDEWEB)
Badarch, U.
2007-07-01
The present thesis is organized as follows. In Chapter 2 we study the Nucleon-Nucleon (NN) interaction in Dirac-Brueckner (DB) approach. We start by considering the NN interaction in free-space in terms of the Bethe-Salpeter (BS) equation to the meson exchange potential model. Then we present the DB approach for nuclear matter by extending the BS equation for the in-medium NN interaction. From the solution of the three-dimensional in-medium BS equation, we derive the DB self-energies and total binding energy which are the main results of the DB approach, which we later incorporate in the field theoretical calculation of the nuclear equation of state. In Chapter 3, we introduce the basic concepts of density functional theory in the context of Quantum Hadrodynamics (QHD-I). We reach the main point of this work in Chapter 4 where we introduce the DDRH approach. In the DDRH theory, the medium dependence of the meson-nucleon vertices is expressed as functionals of the baryon field operators. Because of the complexities of the operator-valued functionals we decide to use the mean-field approximation. In Chapter 5, we contrast microscopic and phenomenological approaches to extracting density dependent meson-baryon vertices. Chapter 6 gives the results of our studies of the EOS of infinite nuclear matter in detail. Using formulas derived in Chapters 4 and 5 we calculate the properties of symmetric and asymmetric nuclear matter and pure neutron matter. (orig.)
Chiral thermodynamics of nuclear matter
Energy Technology Data Exchange (ETDEWEB)
Fiorilla, Salvatore
2012-10-23
The equation of state of nuclear matter is calculated at finite temperature in the framework of in-medium chiral perturbation theory up to three-loop order. The dependence of its thermodynamic properties on the isospin-asymmetry is investigated. The chiral quark condensate is evaluated for symmetric nuclear matter. Its behaviour as a function of density and temperature sets important nuclear physics constraints for the QCD phase diagram.
Functional renormalization group study of nuclear and neutron matter
Energy Technology Data Exchange (ETDEWEB)
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.
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...
Nuclear fusion inside condense matters
Institute of Scientific and Technical Information of China (English)
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
International Nuclear Information System (INIS)
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)
Bosonic variables in nuclear matters
International Nuclear Information System (INIS)
It is shown that the boson theoretical interpretation of nuclear forces nessecitates the introduction of bosonic variables within the state function of nuclear matter. In this framework the 2-boson exchange plays a decisive role and calls for the introduction of special selfenergy diagrams. This generalized scheme is discussed with the help of a solvable field theoretical model. (orig.)
Exposing asymmetric gray matter vulnerability in amyotrophic lateral sclerosis
Directory of Open Access Journals (Sweden)
Matthew S. Devine
2015-01-01
Full Text Available Limb weakness in amyotrophic lateral sclerosis (ALS is typically asymmetric. Previous studies have identified an effect of limb dominance on onset and spread of weakness, however relative atrophy of dominant and non-dominant brain regions has not been investigated. Our objective was to use voxel-based morphometry (VBM to explore gray matter (GM asymmetry in ALS, in the context of limb dominance. 30 ALS subjects were matched with 17 healthy controls. All subjects were right-handed. Each underwent a structural MRI sequence, from which GM segmentations were generated. Patterns of GM atrophy were assessed in ALS subjects with first weakness in a right-sided limb (n = 15 or left-sided limb (n = 15. Within each group, a voxelwise comparison was also performed between native and mirror GM images, to identify regions of hemispheric GM asymmetry. Subjects with ALS showed disproportionate atrophy of the dominant (left motor cortex hand area, irrespective of the side of first limb weakness (p < 0.01. Asymmetric atrophy of the left somatosensory cortex and temporal gyri was only observed in ALS subjects with right-sided onset of limb weakness. Our VBM protocol, contrasting native and mirror images, was able to more sensitively detect asymmetric GM pathology in a small cohort, compared with standard methods. These findings indicate particular vulnerability of dominant upper limb representation in ALS, supporting previous clinical studies, and with implications for cortical organisation and selective vulnerability.
Exposing asymmetric gray matter vulnerability in amyotrophic lateral sclerosis.
Devine, Matthew S; Pannek, Kerstin; Coulthard, Alan; McCombe, Pamela A; Rose, Stephen E; Henderson, Robert D
2015-01-01
Limb weakness in amyotrophic lateral sclerosis (ALS) is typically asymmetric. Previous studies have identified an effect of limb dominance on onset and spread of weakness, however relative atrophy of dominant and non-dominant brain regions has not been investigated. Our objective was to use voxel-based morphometry (VBM) to explore gray matter (GM) asymmetry in ALS, in the context of limb dominance. 30 ALS subjects were matched with 17 healthy controls. All subjects were right-handed. Each underwent a structural MRI sequence, from which GM segmentations were generated. Patterns of GM atrophy were assessed in ALS subjects with first weakness in a right-sided limb (n = 15) or left-sided limb (n = 15). Within each group, a voxelwise comparison was also performed between native and mirror GM images, to identify regions of hemispheric GM asymmetry. Subjects with ALS showed disproportionate atrophy of the dominant (left) motor cortex hand area, irrespective of the side of first limb weakness (p < 0.01). Asymmetric atrophy of the left somatosensory cortex and temporal gyri was only observed in ALS subjects with right-sided onset of limb weakness. Our VBM protocol, contrasting native and mirror images, was able to more sensitively detect asymmetric GM pathology in a small cohort, compared with standard methods. These findings indicate particular vulnerability of dominant upper limb representation in ALS, supporting previous clinical studies, and with implications for cortical organisation and selective vulnerability. PMID:25844330
Linear response of homogeneous nuclear matter with energy density functionals
Energy Technology Data Exchange (ETDEWEB)
Pastore, A. [Institut d’Astronomie et d’Astrophysique, CP 226, Université Libre de Bruxelles, B-1050 Bruxelles (Belgium); Davesne, D., E-mail: davesne@ipnl.in2p3.fr [Institut de Physique Nucléaire de Lyon, CNRS-IN2P3, UMR 5822, Université Lyon 1, F-69622 Villeurbanne (France); Navarro, J. [IFIC (CSIC University of Valencia), Apdo. Postal 22085, E-46071 Valencia (Spain)
2015-03-01
Response functions of infinite nuclear matter with arbitrary isospin asymmetry are studied in the framework of the random phase approximation. The residual interaction is derived from a general nuclear Skyrme energy density functional. Besides the usual central, spin–orbit and tensor terms it could also include other components as new density-dependent terms or three-body terms. Algebraic expressions for the response functions are obtained from the Bethe–Salpeter equation for the particle–hole propagator. Applications to symmetric nuclear matter, pure neutron matter and asymmetric nuclear matter are presented and discussed. Spin–isospin strength functions are analyzed for varying conditions of density, momentum transfer, isospin asymmetry, and temperature for some representative Skyrme functionals. Particular attention is paid to the discussion of instabilities, either real or unphysical, which could manifest in finite nuclei.
Energy Technology Data Exchange (ETDEWEB)
Chapman, S.
1992-11-01
The goal in this thesis is thus twofold: The first is to investigate the feasibility of using heavy ion collisions to create conditions in the laboratory which are ripe for the formation of a quark-gluon plasma. The second is to develop a technique for studying some of the many non-perturbative features of this novel phase of matter.
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.
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
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.
Energy Technology Data Exchange (ETDEWEB)
Heiselberg, H. [NORDITA, Copenhagen (Denmark)
1998-06-01
The kaon energy in a nuclear medium and its dependence on kaon-nucleon and nucleon-nucleon correlations is discussed. The transition from the Lenz potential at low densities to the Hartree potential at high densities can be calculated analytically by making a Wigner-Seitz cell approximation and employing a square well potential. As the Hartree potential is less attractive than the Lenz one, kaon condensation inside cores of neutron stars appears to be less likely than previously estimated. (orig.)
Instability in relativistic nuclear matter
International Nuclear Information System (INIS)
The stability of the Fermi gas state in the nuclear matter which satisfies the saturation property is considered relativistically. It is shown that the Fermi gas state is stable at very low density and at high density, but it is unstable for density fluctuation in the intermediate density region including the normal density. (author)
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...
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...
The modulation effect for supersymmetric dark matter detection with asymmetric velocity dispersion
Vergados, J D
2000-01-01
The detection of the theoretically expected dark matter is central to particle physics cosmology. Current fashionable supersymmetric models provide a natural dark matter candidate which is the lightest supersymmetric particle (LSP). Such models combined with fairly well understood physics like the quark substructure of the nucleon and the nuclear form factor and the spin response function of the nucleus, permit the evaluation of the event rate for LSP-nucleus elastic scattering. The thus obtained event rates are, however, very low or even undetectable. So it is imperative to exploit the modulation effect, i.e. the dependence of the event rate on the earth's annual motion. In this review we study such a modulation effect in directional and undirectional experiments. We calculate both the differential and the total rates using symmetric as well as asymmetric velocity distributions. We find that in the symmetric case the modulation amplitude is small, less than 0.07. There exist, however, regions of the phase sp...
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.
Symmetry energy: from nuclear matter to finite nuclei
Kolomietz, V M
2014-01-01
We suggest a particular procedure of derivation of the beta-stability line and isotopic symmetry energy. The behavior of the symmetry energy coefficient $b(A,N-Z)$ is analyzed. We redefine the surface tension coefficient and the surface symmetry energy for an asymmetric nuclear Fermi-liquid drop with a finite diffuse layer. Following Gibbs-Tolman concept, we introduce the equimolar radius at which the surface tension is applied. The relation of the nuclear macroscopic characteristics like surface and symmetry energies, Tolman length, etc. to the bulk properties of nuclear matter is considered. The surface-to-volume symmetry energy ratio for several Skyrme-force parametrizations is obtained.
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.
Aspects of particle production in isospin-asymmetric matter
Ferini, G.; Colonna, M.; Gaitanos, T.; Di Toro, M.
2005-11-01
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/K 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 GeV beam energy region. In particular, K 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/K 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.
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.
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...
DS Mesons in Asymmetric Hot and Dense Hadronic Matter
Directory of Open Access Journals (Sweden)
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.
Nuclear interactions and hadronic matter
International Nuclear Information System (INIS)
The new generation of heavy ion accelerators and complex experimental devices, developed in the last two decades, give access to new information concerning the dynamics of nuclear collisions and allow to obtain and study in the laboratory the nuclear matter under extreme conditions of density and temperature. Of special interest is the intermediate energy region where the reactions are dominated by the competition between the mean field and nucleon-nucleon interaction. Fundamental aspects of nuclear reaction studies are probed at different instants of a nuclear collision. One can learn about the transport properties of nuclear matter in pure nucleonic regime and understand the modification of the nucleon-nucleon cross section due to various in-medium effects: density effects, effective mass, quantum effects, three-body interactions. With increasing energy, fast particle emission associated with direct nucleon-nucleon collisions in the first steps of the reaction come into play too. At higher energy, flow measurements are crucial tests of the influence of medium effects by probing the elastic part of the nucleon-nucleon collisions. On the other side, at higher incident energies, the characteristics of the nuclear equation of state (EoS) can be studied if local thermal and chemical equilibrium turns out to be established. Understanding of the properties of the nuclear matter in extreme conditions is a fundamental goal. The EoS is also an essential ingredient in the description of the massive stars leading to supernova explosion and neutron star formation. Experimental studies of such aspects needs experimental devices of high complexity which can detect and identify event by event all products coming out from heavy ion interactions at intermediate, relativistic and ultra-relativistic energies, having as complete as possible information on their mass, charge, velocity vector. CHIMERA and FOPI are such devices for intermediate and relativistic energy, respectively. Our
Shear viscosity of nuclear matter
Magner, A G; Grygoriev, U V; Plujko, V A
2016-01-01
Shear viscosity $\\eta$ is calculated for the nuclear matter described as a system of interacting nucleons with the van der Waals (VDW) equation of state. The Boltzmann-Vlasov kinetic equation is solved in terms of the plane waves of the collective overdamped motion. In the frequent collision regime, the shear viscosity depends on the particle number density $n$ through the mean-field parameter $a$ which describes attractive forces in the VDW equation. In the temperature region $T=15\\div 40$~MeV, a ratio of the shear viscosity to the entropy density $s$ is smaller than 1 at the nucleon number density $n =(0.5\\div 1.5)\\,n^{}_0$, where $n^{}_0=0.16\\,$fm$^{-3}$ is the particle density of equilibrium nuclear matter at zero temperature. A minimum of the $\\eta/s$ ratio takes place somewhere in a vicinity of the critical point of the VDW system. Large values of $\\eta/s\\gg 1$ are however found in both the low density, $n\\ll n^{}_0$, and high density, $n>2n^{}_0$, regions. This makes the ideal hydrodynamic approach ina...
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.
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.
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...
Asymmetric capture of Dirac dark matter by the Sun
Blennow, Mattias
2015-01-01
Current problems with the solar model may be alleviated if a significant amount of dark matter from the galactic halo is captured in the Sun. We discuss the capture process in the case where the dark matter is a Dirac fermion and the background halo consists of equal amounts of dark matter and anti-dark matter. By considering the case where dark matter and anti-dark matter have different cross sections on solar nuclei as well as the case where the capture process is considered to be a Poisson process, we find that a significant asymmetry between the captured dark particles and anti-particles is possible. Such an asymmetry puts a lower bound on the total amount of captured dark matter and could be a possible solution to the solar composition problem.
Towards the nuclear matter - quark matter phase transition
International Nuclear Information System (INIS)
The conjectured first order phase transition from cold nuclear to cold quark matter is considered. It is found that non-perturbative effects due to instantons may have a 'smoothing-out' effect on the transition. (author)
Asymmetrical sabotage tactics, nuclear facilities/materials, and vulnerability analysis
International Nuclear Information System (INIS)
Full text: The emerging paradigm of a global community wherein post-modern political violence is a fact of life that must be dealt with by safety and security planners is discussed. This paradigm shift in the philosophy of terrorism is documented by analysis of the emerging pattern of asymmetrical tactics being employed by terrorists. Such philosophical developments in violent political movements suggest a shift in the risks that security and safety personnel must account for in their planning for physical protection of fixed site nuclear source facilities like power generation stations and the eventual storage and transportation of the by-products of these facilities like spent nuclear fuel and other high level wastes. This paper presents a framework for identifying these new political realities and related threat profiles, suggests ways in which security planners and administrators can design physical protection practices to meet these emerging threats, and argues for global adoption of standards for the protection of nuclear facilities that could be used as a source site from which terrorists could inflict a mass contamination event and for standards related to the protection of the waste materials that can be used in the production of radiological weapons of mass victimization. (author)
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.
Neutron skin thickness and nuclear matter properties
Yoshida, S.; Sagawa, H.
2007-08-01
Linear correlations are found among the isovector nuclear matter properties in both the Skyrme-Hartree-Fock (SHF) and the relativistic mean-field (RMF) models. In addition, we found a kind of correlation between the isovector nuclear matter properties and the incompressibility in the SHF model. The Skyrme parameters are related analytically to nuclear matter properties with the Thomas—Fermi approximation. By using a linear correlation between the neutron skin thickness and the pressure of the neutron matter in the SHF model, we show that the neutron skin thickness of 208Pb gives crucial information about not only the neutron equation of state but also the isovector nuclear matter properties and the parametrization of Skyrme interaction.
Nuclear Matter in Relativistic Mean Field Theory with Isovector Scalar Meson
Kubis, S
1997-01-01
Relativistic mean field (RMF) theory of nuclear matter with the isovector scalar mean field corresponding to the delta-meson [a_0(980)] is studied. While the delta-meson mean field vanishes in symmetric nuclear matter, it can influence properties of asymmetric nuclear matter in neutron stars. The RMF contribution due to delta-field to the nuclear symmetry energy is negative. To fit the empirical value, E_s=30 MeV, a stronger rho-meson coupling is required than in the absence of the delta-field. The energy per particle of neutron matter is then larger at high densities than the one with no delta-field included. Also, the proton fraction of beta-stable matter increases. Splitting of proton and neutron effective masses due to the delta-field can affect transport properties of neutron star matter.
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...
Hyperons in nuclear matter from SU(3) chiral effective field theory
Energy Technology Data Exchange (ETDEWEB)
Petschauer, S.; Kaiser, N. [Technische Universitaet Muenchen, Physik Department, Garching (Germany); Haidenbauer, J. [Institut fuer Kernphysik, Forschungszentrum Juelich, Institute for Advanced Simulation, Juelich Center for Hadron Physics, Juelich (Germany); Meissner, Ulf G. [Institut fuer Kernphysik, Forschungszentrum Juelich, Institute for Advanced Simulation, Juelich Center for Hadron Physics, Juelich (Germany); Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik and Bethe Center for Theoretical Physics, Bonn (Germany); Weise, W. [Technische Universitaet Muenchen, Physik Department, Garching (Germany); Villa Tambosi, ECT, Villazzano (Trento) (Italy)
2016-01-15
Brueckner theory is used to investigate the properties of hyperons in nuclear matter. The hyperon-nucleon interaction is taken from chiral effective field theory at next-to-leading order with SU(3) symmetric low-energy constants. Furthermore, the underlying nucleon-nucleon interaction is also derived within chiral effective field theory. We present the single-particle potentials of Λ and Σ hyperons in symmetric and asymmetric nuclear matter computed with the continuous choice for intermediate spectra. The results are in good agreement with the empirical information. In particular, our calculation gives a repulsive Σ-nuclear potential and a weak Λ-nuclear spin-orbit force. (orig.)
Baryogenesis and asymmetric dark matter from the left–right mirror symmetric model
International Nuclear Information System (INIS)
The paper suggests a left–right mirror symmetric model to account for the baryogenesis and asymmetric dark matter. The model can simultaneously accommodate the standard model, neutrino physics, matter–antimatter asymmetry and dark matter. In particular, it naturally and elegantly explains the origin of the baryon and dark matter asymmetries, and clearly gives the close interrelations of them. In addition, the model predicts a number of interesting results, e.g. that the cold dark matter neutrino mass is 3.1 times the proton mass. It is also feasible and promising to test the model in future experiments
Phi meson spectral moments and QCD condensates in nuclear matter
Gubler, Philipp; Weise, Wolfram
2016-10-01
A detailed analysis of the lowest two moments of the ϕ meson spectral function in vacuum and nuclear matter is performed. The consistency is examined between the constraints derived from finite energy QCD sum rules and the spectra computed within an improved vector dominance model, incorporating the coupling of kaonic degrees of freedom with the bare ϕ meson. In the vacuum, recent accurate measurements of the e+e- →K+K- cross section allow us to determine the spectral function with high precision. In nuclear matter, the modification of the spectral function can be described by the interactions of the kaons from ϕ → K K ‾ with the surrounding nuclear medium. This leads primarily to a strong broadening and an asymmetric deformation of the ϕ meson peak structure. We confirm that, both in vacuum and nuclear matter, the zeroth and first moments of the corresponding spectral functions satisfy the requirements of the finite energy sum rules to a remarkable degree of accuracy. Limits on the strangeness sigma term of the nucleon are examined in this context. Applying our results to the second moment of the spectrum, we furthermore discuss constraints on four-quark condensates and the validity of the commonly used ground state saturation approximation.
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...
Bordbar, G H; Taghizade, M
2015-01-01
In this work, we have done a completely microscopic calculation using a many-body variational method based on the cluster expansion of energy to compute the asymmetry energy of nuclear matter. In our calculations, we have employed the $AV_{18}$ nuclear potential. We have also investigated the temperature and density dependence of asymmetry energy. Our results show that the asymmetry energy of nuclear matter depends on both density and temperature. We have also studied the effects of different terms in the asymmetry energy of nuclear matter. These investigations indicate that at different densities and temperatures, the contribution of parabolic term is very substantial with respect to the other terms. Therefore, we can conclude that the parabolic approximation is a relatively good estimation, and our calculated binding energy of asymmetric nuclear matter is in a relatively good agreement with that of semi-empirical mass formula. However, for the accurate calculations, it is better to consider the effects of o...
Light asymmetric dark matter from new strong dynamics
DEFF Research Database (Denmark)
Frandsen, Mads Toudal; Sarkar, Subir; Schmidt-Hoberg, Kai
2011-01-01
A ~5 GeV `dark baryon' with a cosmic asymmetry similar to that of baryons is a natural candidate for the dark matter. We study the possibility of generating such a state through dynamical electroweak symmetry breaking, and show that it can share the relic baryon asymmetry via sphaleron interactions...
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.
Nucleon mean free path in nuclear matter
International Nuclear Information System (INIS)
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.)
Asymmetric dark matter from spontaneous cogenesis in the supersymmetric standard model
Energy Technology Data Exchange (ETDEWEB)
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.)
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.
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...
Nuclear matter in all its states
International Nuclear Information System (INIS)
This report includes the nine lectures which have been presented at the Joliot-Curie School of Nuclear Physics in 1985. The subjects covered are the following: thermodynamic description of excited nuclei; heavy ion reactions at high energy (theoretical approach); heavy ion reactions at high energy (experimental approach); relativistic nuclear physics and quark effects in nuclei; quark matter; nuclear compressibility and its experimental determinations; hot nuclei; anti p-nucleus interaction; geant resonances at finite temperature
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
Energy Technology Data Exchange (ETDEWEB)
Baldes, Iason; Bell, Nicole F.; Millar, Alexander J.; Volkas, Raymond R. [ARC Centre of Excellence for Particle Physics at the Terascale,School of Physics, The University of Melbourne, Victoria, 3010 (Australia)
2015-10-21
We explore possible asymmetric dark matter models using CP violating scatterings to generate an asymmetry. In particular, we introduce a new model, based on DM fields coupling to the SM Higgs and lepton doublets, a neutrino portal, and explore its UV completions. We study the CP violation and asymmetry formation of this model, to demonstrate that it is capable of producing the correct abundance of dark matter and the observed matter-antimatter asymmetry. Crucial to achieving this is the introduction of interactions which violate CP with a T{sup 2} dependence.
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...
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...
Nuclear "pasta matter" for different proton fractions
Schuetrumpf, B.; Iida, K.; Maruhn, J. A.; Reinhard, P.-G.
2014-11-01
Nuclear matter under astrophysical conditions is explored with time-dependent and static Hartree-Fock calculations. The focus is in a regime of densities where matter segregates into liquid and gaseous phases unfolding a rich scenario of geometries, often called nuclear pasta shapes (e.g., spaghetti, lasagna). Particularly the appearance of the different phases depending on the proton fraction and the transition to uniform matter are investigated. In this context the neutron background density is of special interest, because it plays a crucial role in the type of pasta shape that is built. The study is performed in two dynamical ranges, once for hot matter and once at temperature zero, to investigate the effect of cooling.
Nuclear Pasta Matter for Different Proton Fractions
Schütrumpf, B; Maruhn, J A; Reinhard, P -G
2014-01-01
Nuclear matter under astrophysical conditions is explored with time-dependent and static Hartree-Fock calculations. The focus is in a regime of densities where matter segregates into liquid and gaseous phases unfolding a rich scenario of geometries, often called nuclear pasta shapes (e.g. spaghetti, lasagna). Particularly the appearance of the different phases depending on the proton fraction and the transition to uniform matter are investigated. In this context the neutron background density is of special interest, because it plays a crucial role for the type of pasta shape which is built. The study is performed in two dynamical ranges, one for hot matter and one at temperature zero to investigate the effect of cooling.
Spin-Polarized States of Nuclear Matter
Institute of Scientific and Technical Information of China (English)
ZUO Wei; U. Lombardo; SHEN Cai-Wan
2003-01-01
The equations of state of spin-polarized nuclear matter and pure neutron matter are studied in theframework of the Brueckner-Hartree-Fock theory including a three-body force. The energy per nucleon E A (δ) calculatedin the full range of spin polarization δ = (ρ↑ - ρ↓)/ρ for symmetric nuclear matter and pure neutron matter fulfills aparabolic law. In both the cases the spin-symmetry energy is calculated as a function of the baryonic density alongwith the related quantities such as the magnetic susceptibility and the Landau parameter Go. The main effect of thethree-body force is to strongly reduce the degenerate Fermi gas magnetic susceptibility even more than the value withonly two-body force. The equation of state is monotonically increasing with the density for all spin-aligned configurationsstudied here so that no any signature is found for a spontaneous transition to a ferromagnetic state.
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 ...
Nuclear matter theory. [Realistic forces, review
Energy Technology Data Exchange (ETDEWEB)
Negele, J.W.
1977-01-01
Recent advances in variational and perturbative theories are surveyed which offer genuine promise that nuclear matter will soon become a viable tool for investigating nuclear interactions. The basic elements of the hypernetted chain expansion for Jastrow variational functions are briefly reviewed, and comparisons of variational and perturbative results for a series of increasingly complicated systems are presented. Prospects for investigating realistic forces are assessed and the unresolved, open problems are summarized.
Femtotechnology: Nuclear Matter with Fantastic Properties
Directory of Open Access Journals (Sweden)
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
Nuclear and Quark Matter at High Temperature
Biro, T S; Schram, Z
2016-01-01
We review important ideas on nuclear and quark matter description on the basis of high- temperature field theory concepts, like resummation, dimensional reduction, interaction scale separation and spectral function modification in media. Statistical and thermodynamical concepts are spotted in the light of these methods concentrating on the - partially still open - problems of the hadronization process.
Condensed matter studies by nuclear methods
International Nuclear Information System (INIS)
The separate abstract was prepared for 1 of the papers in this volume. The remaining 13 papers dealing with the use but not with advances in the use of nuclear methods in studies of condensed matter, were considered outside the subject scope of INIS. (M.F.W.)
Probing cold dense nuclear matter
International Nuclear Information System (INIS)
The protons and neutrons in a nucleus can form strongly correlated nucleon pairs. Scattering experiments, in which a proton is knocked out of the nucleus with high-momentum transfer and high missing momentum, show that in carbon-12 the neutron-proton pairs are nearly 20 times as prevalent as proton-proton pairs and, by inference, neutron-neutron pairs. This difference between the types of pairs is due to the nature of the strong force and has implications for understanding cold dense nuclear systems such as neutron stars
Probing Cold Dense Nuclear Matter
International Nuclear Information System (INIS)
The protons and neutrons in a nucleus can form strongly correlated nucleon pairs. Scattering experiments, in which a proton is knocked out of the nucleus with high-momentum transfer and high missing momentum, show that in carbon-12 the neutron-proton pairs are nearly 20 times as prevalent as proton-proton pairs and, by inference, neutron-neutron pairs. This difference between the types of pairs is due to the nature of the strong force and has implications for understanding cold dense nuclear systems such as neutron stars.
Probing cold dense nuclear matter.
Energy Technology Data Exchange (ETDEWEB)
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
Energy Technology Data Exchange (ETDEWEB)
Subedi, Ramesh; Shneor, R.; Monaghan, Peter; Anderson, Bryon; Aniol, Konrad; Annand, John; Arrington, John; Benaoum, Hachemi; Benmokhtar, Fatiha; Bertozzi, William; Boeglin, Werner; Chen, Jian-Ping; Choi, Seonho; Cisbani, Evaristo; Craver, Brandon; Frullani, Salvatore; Garibaldi, Franco; Gilad, Shalev; Gilman, Ronald; Glamazdin, Oleksandr; Hansen, Jens-Ole; Higinbotham, Douglas; Holmstrom, Timothy; Ibrahim, Hassan; Igarashi, Ryuichi; De Jager, Cornelis; Jans, Eddy; Jiang, Xiaodong; Kaufman, Lisa; Kelleher, Aidan; Kolarkar, Ameya; Kumbartzki, Gerfried; LeRose, John; Lindgren, Richard; Liyanage, Nilanga; Margaziotis, Demetrius; Markowitz, Pete; Marrone, Stefano; Mazouz, Malek; Meekins, David; Michaels, Robert; Moffit, Bryan; Perdrisat, Charles; Piasetzky, Eliazer; Potokar, Milan; Punjabi, Vina; Qiang, Yi; Reinhold, Joerg; Ron, Guy; Rosner, Guenther; Saha, Arunava; Sawatzky, Bradley; Shahinyan, Albert; Sirca, Simon; Slifer, Karl; Solvignon, Patricia; Sulkosky, Vince; Sulkosky, Vincent; Sulkosky, Vince; Sulkosky, Vincent; Urciuoli, Guido; Voutier, Eric; Watson, John; Weinstein, Lawrence; Wojtsekhowski, Bogdan; Wood, Stephen; Zheng, Xiaochao; Zhu, Lingyan
2008-06-01
The protons and neutrons in a nucleus can form strongly correlated nucleon pairs. Scattering experiments, in which a proton is knocked out of the nucleus with high-momentum transfer and high missing momentum, show that in carbon-12 the neutron-proton pairs are nearly 20 times as prevalent as proton-proton pairs and, by inference, neutron-neutron pairs. This difference between the types of pairs is due to the nature of the strong force and has implications for understanding cold dense nuclear systems such as neutron stars.
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.
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.
Chiral density wave in nuclear matter
Energy Technology Data Exchange (ETDEWEB)
Heinz, Achim [Institute for Theoretical Physics, Goethe University, Max-von-Laue-Str. 1, D-60438 Frankfurt am Main (Germany); Giacosa, Francesco [Institute for Theoretical Physics, Goethe University, Max-von-Laue-Str. 1, D-60438 Frankfurt am Main (Germany); Institute of Physics, Jan Kochanowski University, 25-406 Kielce (Poland); Rischke, Dirk H. [Institute for Theoretical Physics, Goethe University, Max-von-Laue-Str. 1, D-60438 Frankfurt am Main (Germany)
2015-01-15
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 2.4ρ{sub 0}, where ρ{sub 0} is the nuclear matter ground-state density.
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...
From QCD to nuclear matter saturation
Energy Technology Data Exchange (ETDEWEB)
Ericson, Magda [Universite de Lyon, Univ. Lyon 1, CNRS/IN2P3, IPN Lyon, F-69622 Villeurbanne Cedex (France)]|[Theory division, CERN, CH-12111 Geneva (Switzerland); Chanfray, Guy [Universite de Lyon, Univ. Lyon 1, CNRS/IN2P3, IPN Lyon, F-69622 Villeurbanne Cedex (France)
2007-03-15
We discuss a relativistic chiral theory of nuclear matter with {sigma} and {omega} exchange using a formulation of the {sigma} model in which all the chiral constraints are automatically fulfilled. We establish a relation between the nuclear response to the scalar field and the QCD one which includes the nucleonic parts. It allows a comparison between nuclear and QCD information. Going beyond the mean field approach we introduce the effects of the pion loops supplemented by the short-range interaction. The corresponding Landau-Migdal parameters are taken from spin-isospin physics results. The parameters linked to the scalar meson exchange are extracted from lattice QCD results. These inputs lead to a reasonable description of the saturation properties, illustrating the link between QCD and nuclear physics. We also derive from the corresponding equation of state the density dependence of the quark condensate and of the QCD susceptibilities. (authors)
Wanted! Nuclear Data for Dark Matter Astrophysics
International Nuclear Information System (INIS)
Astronomical observations from small galaxies to the largest scales in the universe can be consistently explained by the simple idea of dark matter. The nature of dark matter is however still unknown. Empirically it cannot be any of the known particles, and many theories postulate it as a new elementary particle. Searches for dark matter particles are under way: production at high-energy accelerators, direct detection through dark matter-nucleus scattering, indirect detection through cosmic rays, gamma rays, or effects on stars. Particle dark matter searches rely on observing an excess of events above background, and a lot of controversies have arisen over the origin of observed excesses. With the new high-quality cosmic ray measurements from the AMS-02 experiment, the major uncertainty in modeling cosmic ray fluxes is in the nuclear physics cross sections for spallation and fragmentation of cosmic rays off interstellar hydrogen and helium. The understanding of direct detection backgrounds is limited by poor knowledge of cosmic ray activation in detector materials, with order of magnitude differences between simulation codes. A scarcity of data on nucleon spin densities blurs the connection between dark matter theory and experiments. What is needed, ideally, are more and better measurements of spallation cross sections relevant to cosmic rays and cosmogenic activation, and data on the nucleon spin densities in nuclei
A variational theory of nuclear matter. III
International Nuclear Information System (INIS)
Developments in a variational theory of nuclear matter for treating v6 homework potentials that include central, spin, isospin and tensor operators are reported. The central, spin, isospin and tensor correlations are parametrized by their range d, and the magnitudes of the non-central correlations. Integral equations are used to sum Fermi hypernetted chain, and single operator chain diagrams. All commutators required to evaluate the energy from the operator chain functions are treated exactly, and the energy is found to have a minimum with respect to variations in all parameters. Results of calculations with v6 models based on the Reid and Bethe-Johnson potentials are reported. A crude estimate of the effect of the spin-orbit potentials on nuclear matter binding energy indicates that it could be significant. (Auth.)
A Separable Pairing Force in Nuclear Matter
Institute of Scientific and Technical Information of China (English)
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.
Description of a nucleon in nuclear matter
International Nuclear Information System (INIS)
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
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...
Equation of state for isospin asymmetric matter of nucleons and deltas
International Nuclear Information System (INIS)
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)
Stellar properties and nuclear matter constraints
Dutra, Mariana; Menezes, Débora P
2015-01-01
We have analyzed stellar properties of the relativistic mean-field (RMF) parametrizations shown to be consistent with the recently studied constraints related to nuclear matter, pure neutron matter, symmetry energy and its derivatives [Dutra et al., Phys. Rev. C 90, 055203 (2014)]. Our results show that only two RMF parametrizations do not allow the emergence of the direct Urca process, important aspect regarding the evolution of a neutron star. Moreover, among all approved RMF models, fourteen of them produce neutron stars with maximum masses inside the range $1.93\\leqslant M/M_\\odot\\leqslant 2.05$, with $M_\\odot$ being the solar mass. Only three models yield maximum masses above this range and a discussion on the inclusion of hyperons is presented. Finally, we have verified that the models satisfying the neutron star maximum mass constraint do not observe the squared sound velocity bound, namely, $v_s^2 < 1/3$, corroborating recent findings.
Elementary diagrams in nuclear and neutron matter
International Nuclear Information System (INIS)
Variational calculations of nuclear and neutron matter are currently performed using a diagrammatic cluster expansion with the aid of nonlinear integral equations for evaluating expectation values. These are the Fermi hypernetted chain (FHNC) and single-operator chain (SOC) equations, which are a way of doing partial diagram summations to infinite order. A more complete summation can be made by adding elementary diagrams to the procedure. The simplest elementary diagrams appear at the four-body cluster level; there is one such E4 diagram in Bose systems, but 35 diagrams in Fermi systems, which gives a level of approximation called FHNC/4. We developed a novel technique for evaluating these diagrams, by computing and storing 6 three-point functions, Sxyz(r12, r13, r23), where xyz (= ccd, cce, ddd, dde, dee, or eee) denotes the exchange character at the vertices 1, 2, and 3. All 35 Fermi E4 diagrams can be constructed from these 6 functions and other two-point functions that are already calculated. The elementary diagrams are known to be important in some systems like liquid 3He. We expect them to be small in nuclear matter at normal density, but they might become significant at higher densities appropriate for neutron star calculations. This year we programmed the FHNC/4 contributions to the energy and tested them in a number of simple model cases, including liquid 3He and Bethe's homework problem. We get reasonable, but not exact agreement with earlier published work. In nuclear and neutron matter with the Argonne v14 interaction these contributions are indeed small corrections at normal density and grow to only 5-10 MeV/nucleon at 5 times normal density
Hadronization measurements in cold nuclear matter
Energy Technology Data Exchange (ETDEWEB)
Dupre, Raphael [Inst. de Physique Nucleaire (IPN), Orsay (France). et al.
2015-05-01
Hadronization is the non-perturbative process of QCD by which partons become hadrons. It has been studied at high energies through various processes, we focus here on the experiments of lepto-production of hadrons in cold nuclear matter. By studying the dependence of observables to the atomic number of the target, these experimentscan give information on the dynamic of the hadronization at the femtometer scale. In particular, we will present preliminary results from JLab Hall B (CLAS collaboration), which give unprecedented statistical precision. Then, we will present results of a phenomenological study showing how HERMES data can be described with pure energyloss models.
Mass shift of -meson in nuclear matter
Indian Academy of Sciences (India)
J R Morones-Ibarra; Mónica Menchaca Maciel; Ayax Santos-Guevara; Felipe Robledo Padilla
2013-03-01
The propagation of -meson in nuclear matter is studied in the Walecka model, by assuming that the sigma couples to a pair of nucleon–antinucleon states and to particle–hole states. The in-medium effect of - mixing is also studied. For completeness, the coupling of sigma to two virtual pions was also considered. It is found that the -meson mass decreases with respect to its value in vacuum and that the contribution of the - mixing effect on the mass shift is relatively small.
D-mesons and charmonium states in hot isospin asymmetric strange hadronic matter
Energy Technology Data Exchange (ETDEWEB)
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
Variations on a theme of nuclear matter
Energy Technology Data Exchange (ETDEWEB)
Pandharipande, V.R.; Wiringa, R.B.
1979-10-01
The authors review new techniques developed to apply the variational method to the nuclear matter problem. The variational wave function is taken to be (SPi/sub i/
Superfluid nuclear matter in BCS theory and beyond
Institute of Scientific and Technical Information of China (English)
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.
Oscillating asymmetric sneutrino dark matter from the maximally U(1)L supersymmetric inverse seesaw
Chen, Shao-Long; Kang, Zhaofeng
2016-10-01
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 δm, 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 δm ∼10-5 eV, is strongly favored. We also investigate possible natural ways to realize that small δm in the model.
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.
Oscillating asymmetric sneutrino dark matter from the maximally U(1L supersymmetric inverse seesaw
Directory of Open Access Journals (Sweden)
Shao-Long Chen
2016-10-01
Full Text Available The inverse seesaw mechanism provides an attractive approach to generate small neutrino mass, which origins from a tiny U(1L 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(1L symmetric limit. However, even a tiny δm, the mass splitting between sneutrino and anti-sneutrino as a result of the tiny U(1L 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 δm∼10−5 eV, is strongly favored. We also investigate possible natural ways to realize that small δm in the model.
Hirschegg '95: Dynamical properties of hadrons in nuclear matter. Proceedings
International Nuclear Information System (INIS)
The following topics were dealt with: Chiral symmetry, chiral condensates, in-medium effective chiral Lagrangians, Δ's in nuclei, nonperturbative QCD, electron scattering from nuclear matter, nuclear shadowing, QCD sum rules, deconfinement, ultrarelativistic heavy ion collisions, nuclear dimuon and electron pair production, photoproduction from nuclei, subthreshold K+ production, kaon polarization in nuclear matter, charged pion production in relativistic heavy ion collisions, the Nambu-Jona-Lasinio model, the SU(3)LxSU(3)R sigma model, nonequilibrium dense nuclear matter, pion pair production at finite temperature. (HSI)
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...
Symmetry energy of dilute warm nuclear matter.
Natowitz, J B; Röpke, G; Typel, S; Blaschke, D; Bonasera, A; Hagel, K; Klähn, T; Kowalski, S; Qin, L; Shlomo, S; Wada, R; Wolter, H H
2010-05-21
The symmetry energy of nuclear matter is a fundamental ingredient in the investigation of exotic nuclei, heavy-ion collisions, and astrophysical phenomena. New data from heavy-ion collisions can be used to extract the free symmetry energy and the internal symmetry energy at subsaturation densities and temperatures below 10 MeV. Conventional theoretical calculations of the symmetry energy based on mean-field approaches fail to give the correct low-temperature, low-density limit that is governed by correlations, in particular, by the appearance of bound states. A recently developed quantum-statistical approach that takes the formation of clusters into account predicts symmetry energies that are in very good agreement with the experimental data. A consistent description of the symmetry energy is given that joins the correct low-density limit with quasiparticle approaches valid near the saturation density.
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...
Stellar properties and nuclear matter constraints
Dutra, Mariana; Lourenço, Odilon; Menezes, Débora P.
2016-02-01
We analyze the stellar properties of the relativistic mean-field (RMF) parametrizations shown to be consistent with the recently studied constraints related to nuclear matter, pure neutron matter, symmetry energy, and its derivatives [Phys. Rev. C 90, 055203 (2014), 10.1103/PhysRevC.90.055203]. Our results show that only two RMF parametrizations do not allow the emergence of the direct Urca process, important aspect regarding the evolution of a neutron star. Moreover, among all approved RMF models, fourteen of them produce neutron stars with maximum masses inside the range 1.93 ≤M /M⊙≤2.05 , with M⊙ being the solar mass. Only three models yield maximum masses above this range and a discussion on the inclusion of hyperons is presented. Finally, we verified that the models satisfying the neutron star maximum mass constraint do not observe the squared sound velocity bound; namely, vs2RMF models consistent with both constraints, depending on the isoscalar-vector interaction of each parametrization.
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.
Nuclear stopping power in warm and hot dense matter
Energy Technology Data Exchange (ETDEWEB)
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.
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...
QMD application of sub-saturated nuclear matter
Energy Technology Data Exchange (ETDEWEB)
Maruyama, Toshiki; Maruyama, Tomoyuki; Iwamoto, Akira [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Niita, Koji; Chikamatsu, Kazuhiro
1997-05-01
QMD (quantum molecular dynamics) has not been applied to supernova and neutron star matter. We begun to apply QMD, microscopic simulation of nuclear reaction, to the infinite system of nuclear matter. The infinite system was simulated by N particles system under the periodic boundary condition. Pauli potential introduced repulsive force which the same kinds of particles could not approach at phase space, instead of antisymmetrization of the system. Supernova matter was appropriate to the symmetric nuclear matter, the inhomogeneous structure was observed less than 0.8 {rho}{sub 0} of density, but homogeneous more than it. Each nucleus was seen to separate from others less than 0.2 {rho}{sub 0}. Neutron star matter attains {beta} equilibrium and not symmetric matter and the lowest energy was obtained at about 0.03-0.08 of proton content. (S.Y.)
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
Energy Technology Data Exchange (ETDEWEB)
Kolomeitsev, E.E.
1997-02-01
The subject of the doctoral thesis is examination of the properties of kaons in nuclear matter. A specific method is explained that has been developed for the scientific objectives of the thesis and permits description of the kaon-nucleon interactions and kaon-nucleon scattering in a vacuum. The main challenge involved was to find approaches that would enable application of the derived relations out of the kaon mass shell, connected with the second objective, namely to possibly find methods which are independent of models. The way chosen to achieve this goal relied on application of reduction formulas as well as current algebra relations and the PCAC hypothesis. (orig./CB) [Deutsch] Die Arbeit befasst sich mit der Untersuchung der Eigenschaften von Kao nen in Kernmaterie. Zu diesem Zweck wurde ein Verfahren entwickelt, di e Kaon- Nukleon- Wechselwirkung und Kaon- Nukleon- Streuung im Vakuumzu beschreiben. Die Hauptherausforderung bestand darin, dass die abgel eiteten Relationen ausserhalb der Kaonen- Massenschale anwendbar werde n. Eine Nebenforderung war, dass die vorgeschlagenen Verfahren moeglic hst modell- unabhaengig sind. Um dieses Ziel zu erreichen, wurden Redu ktionsformeln, Stromalgebra- Relationen und die PCAC- Hypothese angewe ndet.
Track theory and nuclear photographic emulsions for Dark Matter searches
International Nuclear Information System (INIS)
This work is devoted to the analysis of possibilities of nuclear emulsions for Dark Matter search, particles of which can produce slow recoil-nuclei. Tracks of such recoil-nuclei in developed nuclear emulsion consist from several emulsion grains. The analysis was carried out with Monte-Carlo calculations made on the basis of the Track Theory and the various factors influencing Dark Matter particles registration efficiency were investigated. Problems, which should be solved for optimal utilization of nuclear emulsions in Dark Matter search, were formulated.Body - Highlights: ► Specific features of Dark Matter Search in nuclear photographic emulsions. ► Track theory for WIMP search in nuclear emulsions. ► Primary efficiency for single WIMP registration. ► Properties of primary WIMP registration efficiency. ► Primary registration efficiency of WIMP flow
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.
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
Pion Effect of Nuclear Matter in a Chiral Sigma Model
Institute of Scientific and Technical Information of China (English)
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.
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...
Isovector nuclear matter properties and neutron skin thickness
Yoshida, Satoshi; Sagawa, Hiroyuki
2006-04-01
Correlations among several nuclear matter properties are investigated in the Skyrme Hartree-Fock (SHF) and the relativistic mean field (RMF) models. The Skyrme parameters are related analytically to the isoscalar and isovector nuclear matter properties of the Hamiltonian density. Linear correlations are found among the isovector nuclear matter properties of the Hamiltonian density in both the SHF and the RMF models. We show analytically a singularity at the incompressibility Kc=306 MeV in correlations between the isovector nuclear matter properties and incompressibility with the SHF model, whereas there is no obvious singularity in those correlations with the RMF model. A linear correlation between the neutron skin thickness and the pressure of the neutron matter is given in terms of the ratio between the neutron and nuclear matter densities in the SHF model. We show that the neutron skin thickness gives crucial information about not only the neutron equation of state but also the isovector nuclear matter properties and the parametrization of the Skyrme interaction.
Reflection on penal policy in nuclear matters
International Nuclear Information System (INIS)
This document expresses ethical reflexions as far as nuclear energy development is concerned. The potential diversion of the peaceful use of nuclear energy results in the necessity of a criminal policy which would control the nuclear regulations. For each potential nuclear infringement, systems of laws are established either to prevent damages or to penalize them. (TEC)
Energy Technology Data Exchange (ETDEWEB)
Typel, S.; Wolter, H.H. [Sektion Physik, Univ. Muenchen, Garching (Germany)
1998-06-01
Nuclear matter and ground state properties for (proton and neutron) semi-closed shell nuclei are described in relativistic mean field theory with coupling constants which depend on the vector density. The parametrization of the density dependence for {sigma}-, {omega}- and {rho}-mesons is obtained by fitting to properties of nuclear matter and some finite nuclei. The equation of state for symmetric and asymmetric nuclear matter is discussed. Finite nuclei are described in Hartree approximation, including a charge and an improved center-of-mass correction. Pairing is considered in the BCS approximation. Special attention is directed to the predictions for properties at the neutron and proton driplines, e.g. for separation energies, spin-orbit splittings and density distributions. (orig.)
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.
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.
Isoscalar and isovector nuclear matter properties and neutron skin thickness
Sagawa, H.; Yoshida, S.
2007-11-01
Isoscalar and isovector nuclear matter properties are investigated in the Skyrme Hartree-Fock (SHF) and the relativistic mean field (RMF) models. The Skyrme parameters are related analytically to the isoscalar and the isovector nuclear matter properties of the Hamiltonian density. Linear correlations are found among the isovector nuclear matter properties of the Hamiltonian density in both the SHF and the RMF models. We also discovered that the correlations between the isovector properties and the incompressibility K show a singularity at the critical incompressibility Kc=306 MeV. It is shown that the neutron skin thickness gives crucial information about not only for the neutron EOS but also about the isovector nuclear matter properties and about the parameterization of Skyrme interaction. Charge exchange spin-dipole (SD) excitations are proposed to determine the neutron skin thickness model independently.
Investigations of instabilities in nuclear matter in stochastic relativistic models
Energy Technology Data Exchange (ETDEWEB)
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...
Direct reactions involving pion production in hot nuclear matter
Energy Technology Data Exchange (ETDEWEB)
Voskresenskii, D.N.; Kolomeitsev, E.E. [Moscow Institute of Engineering Physics (Russian Federation)
1995-01-01
Probabilities and differential cross sections for the production of {pi}{sup {minus}} mesons in direct NN {yields} NN{pi}{sup {minus}lk} reactions are calculated with allowance for a change in the NN interaction in nuclear matter. The results are obtained in an analytic form for arbitrary temperatures of matter and arbitrary energies and momenta of pions. 13 refs.
Many-body theory of nuclear and neutron star matter
Energy Technology Data Exchange (ETDEWEB)
Pandharipande, V.R.; Akmal, A.; Ravenhall, D.G. [Dept. of Physics, Univ. of Illinois at Urbana-Champaign, Urbana, IL (United States)
1998-06-01
We present results obtained for nuclei, nuclear and neutron star matter, and neutron star structure obtained with the recent Argonne v{sub 18} two- nucleon and Urbana IX three-nucleon interactions including relativistic boost corrections. These interactions predict that matter will undergo a transition to a spin layered phase with neutral pion condensation. We also consider the possibility of a transition to quark matter. (orig.)
Self-interacting asymmetric dark matter coupled to a light massive dark photon
International Nuclear Information System (INIS)
Dark matter (DM) with sizeable self-interactions mediated by a light species offers a compelling explanation of the observed galactic substructure; furthermore, the direct coupling between DM and a light particle contributes to the DM annihilation in the early universe. If the DM abundance is due to a dark particle-antiparticle asymmetry, the DM annihilation cross-section can be arbitrarily large, and the coupling of DM to the light species can be significant. We consider the case of asymmetric DM interacting via a light (but not necessarily massless) Abelian gauge vector boson, a dark photon. In the massless dark photon limit, gauge invariance mandates that DM be multicomponent, consisting of positive and negative dark ions of different species which partially bind in neutral dark atoms. We argue that a similar conclusion holds for light dark photons; in particular, we establish that the multi-component and atomic character of DM persists in much of the parameter space where the dark photon is sufficiently light to mediate sizeable DM self-interactions. We discuss the cosmological sequence of events in this scenario, including the dark asymmetry generation, the freeze-out of annihilations, the dark recombination and the phase transition which gives mass to the dark photon. We estimate the effect of self-interactions in DM haloes, taking into account this cosmological history. We place constraints based on the observed ellipticity of large haloes, and identify the regimes where DM self-scattering can affect the dynamics of smaller haloes, bringing theory in better agreement with observations. Moreover, we estimate the cosmological abundance of dark photons in various regimes, and derive pertinent bounds
Dark Matter Particle Spectroscopy at the LHC: Generalizing M(T2) to Asymmetric Event Topologies
Energy Technology Data Exchange (ETDEWEB)
Konar, Partha; /Florida U.; Kong, Kyoungchul; /SLAC; Matchev, Konstantin T.; Park, Myeonghun; /Florida U.
2012-04-03
We consider SUSY-like missing energy events at hadron colliders and critically examine the common assumption that the missing energy is the result of two identical missing particles. In order to experimentally test this hypothesis, we generalize the subsystem M{sub T2} variable to the case of asymmetric event topologies, where the two SUSY decay chains terminate in different 'children' particles. In this more general approach, the endpoint M{sub T2(max)} of the M{sub T2} distribution now gives the mass {tilde M}p({tilde M}{sub c}{sup (a)}, {tilde M}{sub c}{sup (b)}) of the parent particles as a function of two input children masses {tilde M}{sub c}{sup (a)} and {tilde M}{sub c}{sup (b)}. We propose two methods for an independent determination of the individual children masses M{sub c}{sup (a)} and M{sub c}{sup (b)}. First, in the presence of upstream transverse momentum PUTM the corresponding function {tilde M}p({tilde M}{sub c}{sup (a)}, {tilde M}{sub c}{sup (b)}, P{sub UTM}) is independent of P{sub UTM} at precisely the right values of the children masses. Second, the previously discussed MT2 'kink' is now generalized to a 'ridge' on the 2-dimensional surface {tilde M}p({tilde M}{sub c}{sup (a)}, {tilde M}{sub c}{sup (b)}). As we show in several examples, quite often there is a special point along that ridge which marks the true values of the children masses. Our results allow collider experiments to probe a multi-component dark matter sector directly and without any theoretical prejudice.
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.
The role of meson dynamics in nuclear matter saturation
International Nuclear Information System (INIS)
The problem of the saturation of nuclea matter in the non-relativistic limit of the model proposed by J.D. Walecka is studied. In the original context nuclear matter saturation is obtained as a direct consequence of relativistic effects and both scalar and vector mesons are treated statically. In the present work we investigate the effect of the meson dynamics for the saturation using a Born-Oppenheimer approximation for the ground state. An upper limit for the saturation curve of nuclear matter and are able to decide now essential is the relativistic treatment of the nucleons for this problem, is obtained. (author)
Relativistic Mean-Field Hadronic Models under Nuclear Matter Constraints
Dutra, M; Avancini, S S; Carlson, B V; Delfino, A; Menezes, D P; Providência, C; Typel, S; Stone, J R
2014-01-01
Relativistic mean-field (RMF) models have been widely used in the study of many hadronic frameworks because of several important aspects not always present in nonrelativistic models, such as intrinsic Lorentz covariance, automatic inclusion of spin, appropriate saturation mechanism for nuclear matter, causality and, therefore, no problems related to superluminal speed of sound. With the aim of identifying the models which best satisfy well known properties of nuclear matter, we have analyzed 263 parameterizations of seven different types of RMF models under three different sets of constraints related to symmetric nuclear matter, pure neutron matter, symmetry energy, and its derivatives. One of these (SET1) is formed of the same constraints used in a recent work in which we analyzed 240 Skyrme parameterizations. The results pointed to 2 models consistent with all constraints. Using another set of constraints, namely, SET2a, formed by the updated versions of the previous one, we found 4 models approved simultan...
Energy Technology Data Exchange (ETDEWEB)
Ducoin, C
2006-10-15
Nuclear matter presents a phase transition of the liquid-gas type. This well-known feature is due to the nuclear interaction profile (mean-range attractive, short-range repulsive). Symmetric-nuclear-matter thermodynamics is thus analogous to that of a Van der Waals fluid. The study shows up to be more complex in the case of asymmetric matter, composed of neutrons and protons in an arbitrary proportion. Isospin, which distinguishes both constituents, gives a measure of this proportion. Studying asymmetric matter, isospin is an additional degree of freedom, which means one more dimension to consider in the space of observables. The nuclear liquid-gas transition is associated with the multi-fragmentation phenomenon observed in heavy-ion collisions, and to compact-star physics: the involved systems are neutron rich, so they are affected by the isospin degree of freedom. The present work is a theoretical study of isospin effects which appear in the asymmetric nuclear matter liquid-gas phase transition. A mean-field approach is used, with a Skyrme nuclear effective interaction. We demonstrate the presence of a first-order phase transition for asymmetric matter, and study the isospin distillation phenomenon associated with this transition. The case of phase separation at thermodynamic equilibrium is compared to spinodal decomposition. Finite size effects are addressed, as well as the influence of the electron gas which is present in the astrophysical context. (author)
Correlated basis theory of nucleon optical potential in nuclear matter
Energy Technology Data Exchange (ETDEWEB)
Fantoni, S.; Friman, B.L.; Pandharipande, V.R.
1983-01-01
A brief, simple outline is given of correlated basis perturbation theory and the criterion is discussed for choosing the correlation operator. Next the choice of the nuclear Hamiltonian is discussed and results obtained for nuclear binding energies, and the real and imaginary parts of the nucleon optical potential in nuclear matter are given. The effect of the nonlocality of the real part of the optical potential on the imaginary part is also discussed. 19 references, 7 figures, 1 table.
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
Energy Technology Data Exchange (ETDEWEB)
Giménez Molinelli, P.A., E-mail: pagm@df.uba.ar [Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and IFIBA, CONICET, Ciudad Universitaria, Buenos Aires 1428 (Argentina); Nichols, J.I. [Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and IFIBA, CONICET, Ciudad Universitaria, Buenos Aires 1428 (Argentina); López, J.A. [Department of Physics, University of Texas at El Paso, El Paso, TX 79968 (United States); Dorso, C.O. [Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and IFIBA, CONICET, Ciudad Universitaria, Buenos Aires 1428 (Argentina)
2014-03-01
Ideal nuclear matter is expected to undergo a first order phase transition at the thermodynamic limit. At such phase transitions the size of density fluctuations (bubbles or droplets) scale with the size of the system. This means that simulations of nuclear matter at sub-saturation densities will inexorably suffer from what is vaguely referred to as “finite size effects”. It is usually thought that these finite size effects can be diminished by imposing periodic boundary conditions and making the system large enough, but as we show in this work, that is actually not the case at sub-saturation densities. In this paper we analyze the equilibrium configurations of molecular dynamics simulations of a classical model for symmetric ideal (uncharged) nuclear matter at sub-saturation densities and low temperatures, where phase coexistence is expected at the thermodynamic limit. We show that the most stable configurations in this density range are almost completely determined by artificial aspects of the simulations (i.e. boundary conditions) and can be predicted analytically by surface minimization. This result is very general and is shown to hold true for several well known semi-classical models of nuclear interaction and even for a simple Lennard-Jones potential. Also, in the limit of very large systems, when “small size” effects can be neglected, those equilibrium configurations seem to be restricted to a few structures reminiscent to the “Pasta Phases” expected in Neutron Star matter, but arising from a completely different origin: In Neutron Star matter, the non-homogeneous structures arise from a competition between nuclear and Coulomb interactions while for ideal nuclear matter they emerge from finite (yet not “small”) size effects. The role of periodic boundary conditions and finite size effects in Neutron Star matter simulations are reexamined.
$J/\\Psi$ mass shift in nuclear matter
Energy Technology Data Exchange (ETDEWEB)
Gastao Krein, Anthony Thomas, Kazuo Tsushima
2011-02-01
The $J/\\Psi$ mass shift in cold nuclear matter is computed using an effective Lagrangian approach. The mass shift is computed by evaluating $D$ and $D^*$ meson loop contributions to the $J/\\Psi$ self-energy employing medium-modified meson masses. The modification of the $D$ and $D^*$ masses in nuclear matter is obtained using the quark-meson coupling model. The loop integrals are regularized with dipole form factors and the sensitivity of the results to the values of form-factor cutoff masses is investigated. The $J/\\Psi$ mass shift arising from the modification of the $D$ and $D^*$ loops at normal nuclear matter density is found to range from $-16$~MeV to $-24$~MeV under a wide variation of values of the cutoff masses. Experimental perspectives for the formation of a bound state of $J/\\Psi$ to a nucleus are investigated.
On growth of spinodal instabilities in nuclear matter
Yilmaz, O; Acar, F; Gokalp, A
2015-01-01
Early growth of density fluctuations of nuclear matter in spinodal region is investigated employing the stochastic mean-field approach. In contrast to the earlier treatments in which only collective modes were included in the calculations, in the present work non-collective modes are also included, thus providing a complete treatment of the density correlation functions. Calculations are carried out for symmetric matter in non-relativistic framework using a semi-classical approximation.
Recent Developments in Cold Fusion / Condensed Matter Nuclear Science
Krivit, Steven B.
2006-03-01
Krivit is recognized internationally as an expert on the subject matter of cold fusion / condensed matter nuclear science. He is the editor of New Energy Times, the leading source of information for the field of cold fusion. He is the author of the 2005 book, The Rebirth of Cold Fusion and founder of New Energy Institute, an independent nonprofit public benefit corporation dedicated to accelerating the progress of new, sustainable and environmentally friendly energy sources.
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
Energy Technology Data Exchange (ETDEWEB)
Martinik, Tomas, E-mail: tomas.martinik@physics.uu.se [Department of Physics and Astronomy, Uppsala University, Box 516 Sweden, SE-75120 Uppsala (Sweden); Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM, 87545 (United States); Henzl, Vladimir [Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM, 87545 (United States); Grape, Sophie; Svärd, Staffan Jacobsson; Jansson, Peter [Department of Physics and Astronomy, Uppsala University, Box 516 Sweden, SE-75120 Uppsala (Sweden); Swinhoe, Martyn T. [Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM, 87545 (United States); Tobin, Stephen J. [Department of Physics and Astronomy, Uppsala University, Box 516 Sweden, SE-75120 Uppsala (Sweden); Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM, 87545 (United States); Swedish Nuclear Fuel and Waste Management Company, Blekholmstorget 30, Box 250, SE-101 24 Stockholm (Sweden)
2015-07-11
Previous simulation studies of Differential Die‐Away (DDA) instrument’s response to active interrogation of spent nuclear fuel from a pressurized water reactor (PWR) yielded promising results in terms of its capability to accurately measure or estimate basic spent fuel assembly (SFA) characteristics, such as multiplication, initial enrichment (IE) and burn-up (BU) as well as the total plutonium content. These studies were however performed only for a subset of idealized SFAs with a symmetric BU with respect to its longitudinal axis. Therefore, to complement the previous results, additional simulations have been performed of the DDA instrument’s response to interrogation of asymmetrically burned spent nuclear fuel in order to determine whether detailed assay of SFAs from all 4 sides will be necessary in real life applications or whether a cost and time saving single sided assay could be used to achieve results of similar quality as previously reported in case of symmetrically burned SFAs. The results of this study suggest that DDA instrument response depends on the position of the individual neutron detectors and in fact can be split in two modes. The first mode, measured by the back detectors, is not significantly sensitive to the spatial distribution of fissile isotopes and neutron absorbers, but rather reflects the total amount of both contributors as in the cases of symmetrically burned SFAs. In contrary, the second mode, measured by the front detectors, yields certain sensitivity to the orientation of the asymmetrically burned SFA inside the assaying instrument. This study thus provides evidence that the DDA instrument can potentially be utilized as necessary in both ways, i.e. a quick determination of the average SFA characteristics in a single assay, as well as a more detailed characterization involving several DDA observables through assay of the SFA from all of its four sides that can possibly map the burn-up distribution and/or identify diversion or
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...
Lectures notes on phase transformations in nuclear matter
López, Jorge A
2000-01-01
The atomic nucleus, despite of being one of the smallest objects found in nature, appears to be large enough to experience phase transitions. The book deals with the liquid and gaseous phases of nuclear matter, as well as with the experimental routes to achieve transformation between them.Theoretical models are introduced from the ground up and with increasing complexity to describe nuclear matter from a statistical and thermodynamical point of view. Modern critical phenomena, heavy ion collisions and computational techniques are presented while establishing a linkage to experimental data.The
Energy-range relations for hadrons in nuclear matter
Strugalski, Z.
1985-01-01
Range-energy relations for hadrons in nuclear matter exist similarly to the range-energy relations for charged particles in materials. When hadrons of GeV kinetic energies collide with atomic nuclei massive enough, events occur in which incident hadron is stopped completely inside the target nucleus without causing particle production - without pion production in particular. The stoppings are always accompanied by intensive emission of nucleons with kinetic energy from about 20 up to about 400 MeV. It was shown experimentally that the mean number of the emitted nucleons is a measure of the mean path in nuclear matter in nucleons on which the incident hadrons are stopped.
Condensates and correlations in nuclear matter
Directory of Open Access Journals (Sweden)
Röpke G.
2010-10-01
Full Text Available Nuclei in dense matter are inﬂuenced by the medium. Solving an A-particle Schroedinger equation including the eﬀects of self-energy and Pauli blocking, a quasiparticle description is introduced. Deriving thermodynamic properties, this approach contains the NSE at low densities as well as mean-ﬁeld approaches at high densities. Consequences for the symmetry energy, the phase transition, the determination of thermodynamic parameters from cluster yields and astrophysical applications are discussed.
Ordered bicontinuous double-diamond morphology in subsaturation nuclear matter
Matsuzaki, M
2006-01-01
We propose to identify the new "intermediate" morphology in subsaturation nuclear matter observed in a recent quantum molecular dynamics simulation with the ordered bicontinuous double-diamond structure known in block copolymers. We estimate its energy density by incorporating the normalized area-volume relation given in a literature into the nuclear liquid drop model. The resulting energy density is higher than the other five known morphologies.
The Modification of the Scalar Field in dense Nuclear Matter
Rożynek, J.
2011-04-01
We show the possible evolution of the nuclear deep inelastic structure function with nuclear density ρ. The nucleon deep inelastic structure function represents distribution of quarks as function of Björken variable x which measures the longitudinal fraction of momentum carried by them during the Deep Inelastic Scattering (DIS) of electrons on nuclear targets. Starting with small density and negative pressure in Nuclear Matter (NM) we have relatively large inter-nucleon distances and increasing role of nuclear interaction mediated by virtual mesons.When the density approaches the saturation point, ρ = ρ0, we have no longer separate mesons and nucleons but eventually modified nucleon Structure Function (SF) in medium. The ratio of nuclear to nucleon SF measured at saturation point is well known as "EMC effect". For larger density, ρ > ρ0, when the localization of quarks is smaller then 0.3 fm, the nucleons overlap. We argue that nucleon mass should start to decrease in order to satisfy the Momentum Sum Rule (MSR) of DIS. These modifications of the nucleon Structure Function (SF) are calculated in the frame of the nuclear Relativistic Mean Field (RMF) convolution model. The correction to the Fermi energy from term proportional to the pressure is very important and its inclusion modifies the Equation of State (EoS) for nuclear matter.
The Modification of the Scalar Field in dense Nuclear Matter
Directory of Open Access Journals (Sweden)
Rożynek J.
2011-04-01
Full Text Available We show the possible evolution of the nuclear deep inelastic structure function with nuclear density ρ. The nucleon deep inelastic structure function represents distribution of quarks as function of Björken variable x which measures the longitudinal fraction of momentum carried by them during the Deep Inelastic Scattering (DIS of electrons on nuclear targets. Starting with small density and negative pressure in Nuclear Matter (NM we have relatively large inter-nucleon distances and increasing role of nuclear interaction mediated by virtual mesons.When the density approaches the saturation point, ρ = ρ0, we have no longer separate mesons and nucleons but eventually modified nucleon Structure Function (SF in medium. The ratio of nuclear to nucleon SF measured at saturation point is well known as “EMC effect”. For larger density, ρ > ρ0, when the localization of quarks is smaller then 0.3 fm, the nucleons overlap. We argue that nucleon mass should start to decrease in order to satisfy the Momentum Sum Rule (MSR of DIS. These modifications of the nucleon Structure Function (SF are calculated in the frame of the nuclear Relativistic Mean Field (RMF convolution model. The correction to the Fermi energy from term proportional to the pressure is very important and its inclusion modifies the Equation of State (EoS for nuclear matter.
Three-dimensional calculation of inhomogeneous nuclear matter
Energy Technology Data Exchange (ETDEWEB)
Okamoto, Minoru; Maruyama, Toshiki; Yabana, Kazuhiro; Tatsumi, Toshitaka [Graduate School of Pure and Applied Science, University of Tsukuba (Japan); Advanced Science Research Center, Japan Atomic Energy Agency (Japan); Graduate School of Pure and Applied Science, University of Tsukuba (Japan); Department of Physics, Kyoto University (Japan)
2012-11-12
We numerically explore the pasta structures and properties of low-density symmetric nuclear matter without any assumption on the geometry. We observe conventional pasta structures, while a mixture of the pasta appears as a meta-stable state at some transient densities. We also analyze the lattice structure of droplets.
Three-dimensional structure of low-density nuclear matter
Energy Technology Data Exchange (ETDEWEB)
Okamoto, Minoru, E-mail: okamoto@nucl.ph.tsukuba.ac.jp [Graduate School of Pure and Applied Science, University of Tsukuba, Tennoudai 1-1-1, Tsukuba, Ibaraki 305-8571 (Japan); Advanced Science Research Center, Japan Atomic Energy Agency, Shirakata Shirane 2-4, Tokai, Ibaraki 319-1195 (Japan); Maruyama, Toshiki, E-mail: maruyama.toshiki@jaea.go.jp [Advanced Science Research Center, Japan Atomic Energy Agency, Shirakata Shirane 2-4, Tokai, Ibaraki 319-1195 (Japan); Graduate School of Pure and Applied Science, University of Tsukuba, Tennoudai 1-1-1, Tsukuba, Ibaraki 305-8571 (Japan); Yabana, Kazuhiro, E-mail: yabana@nucl.ph.tsukuba.ac.jp [Graduate School of Pure and Applied Science, University of Tsukuba, Tennoudai 1-1-1, Tsukuba, Ibaraki 305-8571 (Japan); Center of Computational Sciences, University of Tsukuba, Tennoudai 1-1-1, Tsukuba, Ibaraki 305-8571 (Japan); Tatsumi, Toshitaka, E-mail: tatsumi@ruby.scphys.kyoto-u.ac.jp [Department of Physics, Kyoto University, Kyoto 606-8502 (Japan)
2012-07-09
We numerically explore the pasta structures and properties of low-density nuclear matter without any assumption on the geometry. We observe conventional pasta structures, while a mixture of the pasta structures appears as a metastable state at some transient densities. We also discuss the lattice structure of droplets.
Three dimensional structure of low-density nuclear matter
Okamoto, Minoru; Yabana, Kazuhiro; Tatsumi, Toshitaka
2011-01-01
We numerically explore the pasta structures and properties of low-density nuclear matter without any assumption on the geometry. We observe conventional pasta structures, while a mixture of the pasta structures appears as a metastable state at some transient densities. We also discuss the lattice structure of droplets.
Nuclear condensation and the equation of state of nuclear matter
International Nuclear Information System (INIS)
The isothermal compression of a dilute nucleonic gas invoking cluster degrees of freedom is studied in an equilibrium statistical model; this clusterized system is found to be more stable than the pure nucleonic system. The equation of state (EoS) of this matter, shows features qualitatively very similar to the one obtained from pure nucleonic gas. In the isothermal compression process, there is a sudden enhancement of clusterization at a transition density rendering features analogous to the gas-liquid phase transition in normal dilute nucleonic matter. Different observables like the caloric curves, heat capacities, isospin distillation, etc are studied in both the models. Possible changes in the observables due to recently indicated medium modifications in the symmetry energy are also investigated
Nuclear condensation and the equation of state of nuclear matter
De, J. N.; Samaddar, S. K.
2007-01-01
The isothermal compression of a dilute nucleonic gas invoking cluster degrees of freedom is studied in an equilibrium statistical model; this clusterized system is found to be more stable than the pure nucleonic system. The equation of state (EoS) of this matter shows features qualitatively very similar to the one obtained from pure nucleonic gas. In the isothermal compression process, there is a sudden enhancement of clusterization at a transition density rendering features analogous to the ...
Relativistic Mean-Field Models and Nuclear Matter Constraints
Dutra, M; Carlson, B V; Delfino, A; Menezes, D P; Avancini, S S; Stone, J R; Providência, C; Typel, S
2013-01-01
This work presents a preliminary study of 147 relativistic mean-field (RMF) hadronic models used in the literature, regarding their behavior in the nuclear matter regime. We analyze here different kinds of such models, namely: (i) linear models, (ii) nonlinear \\sigma^3+\\sigma^4 models, (iii) \\sigma^3+\\sigma^4+\\omega^4 models, (iv) models containing mixing terms in the fields \\sigma and \\omega, (v) density dependent models, and (vi) point-coupling ones. In the finite range models, the attractive (repulsive) interaction is described in the Lagrangian density by the \\sigma (\\omega) field. The isospin dependence of the interaction is modeled by the \\rho meson field. We submit these sets of RMF models to eleven macroscopic (experimental and empirical) constraints, used in a recent study in which 240 Skyrme parametrizations were analyzed. Such constraints cover a wide range of properties related to symmetric nuclear matter (SNM), pure neutron matter (PNM), and both SNM and PNM.
Relativistic mean-field models and nuclear matter constraints
Dutra, M.; Lourenço, O.; Carlson, B. V.; Delfino, A.; Menezes, D. P.; Avancini, S. S.; Stone, J. R.; Providência, C.; Typel, S.
2013-05-01
This work presents a preliminary study of 147 relativistic mean-field (RMF) hadronic models used in the literature, regarding their behavior in the nuclear matter regime. We analyze here different kinds of such models, namely: (i) linear models, (ii) nonlinear σ3 + σ4 models, (iii) σ3 + σ4 + ω4 models, (iv) models containing mixing terms in the fields σ and ω, (v) density dependent models, and (vi) point-coupling ones. In the finite range models, the attractive (repulsive) interaction is described in the Lagrangian density by the σ (ω) field. The isospin dependence of the interaction is modeled by the ρ meson field. We submit these sets of RMF models to eleven macroscopic (experimental and empirical) constraints, used in a recent study in which 240 Skyrme parametrizations were analyzed. Such constraints cover a wide range of properties related to symmetric nuclear matter (SNM), pure neutron matter (PNM), and both SNM and PNM.
Nuclear matter from effective quark-quark interaction.
Baldo, M; Fukukawa, K
2014-12-12
We study neutron matter and symmetric nuclear matter with the quark-meson model for the two-nucleon interaction. The Bethe-Bruckner-Goldstone many-body theory is used to describe the correlations up to the three hole-line approximation with no extra parameters. At variance with other nonrelativistic realistic interactions, the three hole-line contribution turns out to be non-negligible and to have a substantial saturation effect. The saturation point of nuclear matter, the compressibility, the symmetry energy, and its slope are within the phenomenological constraints. Since the interaction also reproduces fairly well the properties of the three-nucleon system, these results indicate that the explicit introduction of the quark degrees of freedom within the considered constituent quark model is expected to reduce the role of three-body forces.
Matter in extremis: Ultrarelativistic nuclear collisions at RHIC
International Nuclear Information System (INIS)
We review the physics of nuclear matter at high energy density and the experimental search for the Quark-Gluon Plasma at the Relativistic Heavy Ion Collider (RHIC). The data obtained in the first three years of the RHIC physics program provide several lines of evidence that a novel state of matter has been created in the most violent, head-on collisions of Au nuclei at √s = 200 GeV. Jet quenching and global measurements show that the initial energy density of the strongly interacting medium generated in the collision is about two orders of magnitude larger than that of cold nuclear matter, well above the critical density for the deconfinement phase transition predicted by lattice QCD. The observed collective flow patterns imply that the system thermalizes early in its evolution, with the dynamics of its expansion consistent with ideal hydrodynamic flow based on a Quark-Gluon Plasma equation of state
Climate Change, Nuclear Power and Nuclear Proliferation: Magnitude Matters
International Nuclear Information System (INIS)
Integrated energy, environment and economics modeling suggests electrical energy use will increase from 2.4 TWe today to 12 TWe in 2100. It will be challenging to provide 40% of this electrical power from combustion with carbon sequestration, as it will be challenging to provide 30% from renewable energy sources. Thus nuclear power may be needed to provide ∼30% by 2100. Calculations of the associated stocks and flows of uranium, plutonium and minor actinides indicate that the proliferation risks at mid-century, using current light-water reactor technology, are daunting. There are institutional arrangements that may be able to provide an acceptable level of risk mitigation, but they will be difficult to implement. If a transition is begun to fast-spectrum reactors at mid-century, without a dramatic change in the proliferation risks of such systems, at the end of the century proliferation risks are much greater, and more resistant to mitigation. The risks of nuclear power should be compared with the risks of the estimated 0.64 C long-term global surface-average temperature rise predicted if nuclear power were replaced with coal-fired power plants without carbon sequestration. Fusion energy, if developed, would provide a source of nuclear power with much lower proliferation risks than fission.
Climate Change, Nuclear Power and Nuclear Proliferation: Magnitude Matters
Energy Technology Data Exchange (ETDEWEB)
Robert J. Goldston
2010-03-03
Integrated energy, environment and economics modeling suggests electrical energy use will increase from 2.4 TWe today to 12 TWe in 2100. It will be challenging to provide 40% of this electrical power from combustion with carbon sequestration, as it will be challenging to provide 30% from renewable energy sources. Thus nuclear power may be needed to provide ~30% by 2100. Calculations of the associated stocks and flows of uranium, plutonium and minor actinides indicate that the proliferation risks at mid-century, using current light-water reactor technology, are daunting. There are institutional arrangements that may be able to provide an acceptable level of risk mitigation, but they will be difficult to implement. If a transition is begun to fast-spectrum reactors at mid-century, without a dramatic change in the proliferation risks of such systems, at the end of the century proliferation risks are much greater, and more resistant to mitigation. The risks of nuclear power should be compared with the risks of the estimated 0.64oC long-term global surface-average temperature rise predicted if nuclear power were replaced with coal-fired power plants without carbon sequestration. Fusion energy, if developed, would provide a source of nuclear power with much lower proliferation risks than fission.
Discrete Wave-Packet Representation in Nuclear Matter Calculations
Müther, H; Kukulin, V I; Pomerantsev, V N
2016-01-01
The Lippmann-Schwinger equation for the nucleon-nucleon $t$-matrix as well as the corresponding Bethe-Goldstone equation to determine the Brueckner reaction matrix in nuclear matter are reformulated in terms of the resolvents for the total two-nucleon Hamiltonians defined in free space and in medium correspondingly. This allows to find solutions at many energies simultaneously by using the respective Hamiltonian matrix diagonalization in the stationary wave packet basis. Among other important advantages, this approach simplifies greatly the whole computation procedures both for coupled-channel $t$-matrix and the Brueckner reaction matrix. Therefore this principally novel scheme is expected to be especially useful for self-consistent nuclear matter calculations because it allows to accelerate in a high degree single-particle potential iterations. Furthermore the method provides direct access to the properties of possible two-nucleon bound states in the nuclear medium. The comparison between reaction matrices f...
Nuclear "pasta" structures in low-density nuclear matter and neutron star crust
Okamoto, Minoru; Yabana, Kazuhiro; Tatsumi, Toshitaka
2013-01-01
In neutron star crust, non-uniform structure of nuclear matter is expected, which is called the "pasta" structure. From the recent studies of giant flares in magnetars, these structures might be related to some observables and physical quantities of the neutron star crust. To investigate the above quantities, we numerically explore the pasta structures with a fully threedimensional geometry and study the properties of low-density nuclear matter, based on the relativistic mean-field model and the Thomas-Fermi approximation. We observe typical pasta structures for fixed proton number-fraction and two of them for cold catalyzed matter. We also discuss the crystalline configuration of "pasta".
Energy Technology Data Exchange (ETDEWEB)
Margueron, J
2001-07-01
We study the elementary interactions between neutrinos and dense matter in a proto-neutron star. Equations of state obtained with different nuclear effective interactions (Skyrme, Gogny, Relativistic Lagrangians) are first discussed. Then, we characterize their stability in spin and isospin. We derive magnetic susceptibilities for all isospin asymmetry values as a function of Landau parameters G{sup {pi}}{sup {pi}}{sup '}{sub 0} (where {pi}, {pi}' = proton or neutron). From this work, we select a parametrization for each of the 3 effective forces: Sly230b,D1P,NL3. We calculate the pure neutron matter and asymmetric nuclear matter response functions with and without charge exchange, describing nuclear correlations in both approaches: non-relativistic (Hartree-Fock with Skyrme forces, then complete RPA) and relativistic (in the Hartree approximation). At the end, we calculate neutrino mean free paths neutral current and charged current reactions. Comparisons between relativistic and non-relativistic approaches allow us to identify relativistic effects in nuclear matter at densities as low as twice the saturation density. RPA correlations make the medium more transparent to neutrinos compared to free Fermi gas. The importance of the effective mass in mean free path calculations is also shown. (author)
Neutron-Proton Mass Difference in Nuclear Matter and in Finite Nuclei and the Nolen-Schiffer Anomaly
Meißner, Ulf-G; Wirzba, A; Yakhshiev, U T
2009-01-01
The neutron-proton mass difference in (isospin asymmetric) nuclear matter and finite nuclei is studied in the framework of a medium-modified Skyrme model. The proposed effective Lagrangian incorporates both the medium influence of the surrounding nuclear environment on the single nucleon properties and an explicit isospin-breaking effect in the mesonic sector. Energy-dependent charged and neutral pion optical potentials in the s- and p-wave channels are included as well. The present approach predicts that the neutron-proton mass difference is mainly dictated by its strong part and that it markedly decreases in neutron matter. Furthermore, the possible interplay between the effective nucleon mass in finite nuclei and the Nolen-Schiffer anomaly is discussed. In particular, we find that a correct description of the properties of mirror nuclei leads to a stringent restriction of possible modifications of the nucleon's effective mass in nuclei.
Chaturvedi, O. S. K.; P.K. Srivastava; Kumar, Ashwini; Singh, B. K.
2016-01-01
The charged particle multiplicity ($n_{ch}$) and pseudorapidity density $(dn_{ch}/d\\eta)$ are key observables to characterize the properties of matter created in heavy ion collisions. The dependence of these observables on collision energy and the collision geometry are a key tool to understand the underlying particle production mechanism. Recently a lot of focus on asymmetric nuclei as well as deformed nuclei collisions has been made as these collisions can provide a deeper understanding of ...
Nuclear matter in the early universe
Energy Technology Data Exchange (ETDEWEB)
Barros, Celso de Camargo, E-mail: barros.celso@ufsc.br [Depto de Física - CFM - Universidade Federal de Santa Catarina - Florianópolis - SC - CP. 476 - CEP 88.040 - 900 - Brazil (Brazil); Cunha, Ivan Eugênio da, E-mail: lordlihige@hotmail.com [Centro Brasileiro de Pesquisas Físicas - CBPF - Rio de Janeiro (Brazil)
2015-12-17
Recently, extreme conditions have been obtained in ultra-relativistic heavy ion collisions at RHIC and at the Large Hadron collider. It is believed that these conditions are similar to the ones of the early Universe, in the time between 10{sup −6}s and 1s, approximately. In this work, the hadrons produced in this range of time will be studied, considering some aspects of the systems produced in the heavy-ion collisions. We will study a phase posterior to the phase transition (in fact it is believed to be a crossover) from the quark-gluon plasma, that is the hadronic phase of the Universe. We will show the model proposed in [1], considering the hadronic matter described by a relativistic model (similar to the Walecka model), considering particles described by quantum equations in a curved spacetime. This curvature is due to the mass and to the strong interactions that appears in the energy-momentum tensor. The set of the equations is proposed in the Robertson-Walker metric, and some approximate solutions are obtained.
Climate Change, Nuclear Power and Nuclear Proliferation: Magnitude Matters
International Nuclear Information System (INIS)
Integrated energy, environment and economics modeling suggests that worldwide electrical energy use will increase from 2.4 TWe today to ∼12 TWe in 2100. It will be challenging to provide 40% of this electrical power from combustion with carbon sequestration, as it will be challenging to provide 30% from renewable energy sources derived from natural energy flows. Thus nuclear power may be needed to provide ∼30%, 3600 GWe, by 2100. Calculations of the associated stocks and flows of uranium, plutonium and minor actinides indicate that the proliferation risks at mid-century, using current light-water reactor technology, are daunting. There are institutional arrangements that may be able to provide an acceptable level of risk mitigation, but they will be difficult to implement. If a transition is begun to fast-spectrum reactors at mid-century, without a dramatic change in the proliferation risks of such systems, at the end of the century global nuclear proliferation risks are much greater, and more resistant to mitigation. Fusion energy, if successfully demonstrated to be economically competitive, would provide a source of nuclear power with much lower proliferation risks than fission.
Climate Change, Nuclear Power and Nuclear Proliferation: Magnitude Matters
Energy Technology Data Exchange (ETDEWEB)
Robert J. Goldston
2011-04-28
Integrated energy, environment and economics modeling suggests that worldwide electrical energy use will increase from 2.4 TWe today to ~12 TWe in 2100. It will be challenging to provide 40% of this electrical power from combustion with carbon sequestration, as it will be challenging to provide 30% from renewable energy sources derived from natural energy flows. Thus nuclear power may be needed to provide ~30%, 3600 GWe, by 2100. Calculations of the associated stocks and flows of uranium, plutonium and minor actinides indicate that the proliferation risks at mid-century, using current light-water reactor technology, are daunting. There are institutional arrangements that may be able to provide an acceptable level of risk mitigation, but they will be difficult to implement. If a transition is begun to fast-spectrum reactors at mid-century, without a dramatic change in the proliferation risks of such systems, at the end of the century global nuclear proliferation risks are much greater, and more resistant to mitigation. Fusion energy, if successfully demonstrated to be economically competitive, would provide a source of nuclear power with much lower proliferation risks than fission.
Phase transitions in high excited nuclear matter
International Nuclear Information System (INIS)
. - The time scale of the thermal multifragmentation in p + Au collision at 8.1 GeV has been measured for the first time (by the analysis of IMF-IMF angular correlations). The mean decay time of the fragmenting system was found to be τ = (50 ± 18) fm/c in accordance with the scenario of a '' simultaneous '' multibody decay of a hot and expanded nuclear system. The measured time-scale is close to that for the density fluctuation in the diluted nuclear system. Hence, the thermal multifragmentation can be interpreted as the first order nuclear liquid-fog phase transition in the spinodal region. - Characteristic temperature Tf is less than Tc - critical temperature for the liquid-gas phase transition. Tc -critical temperature for the liquid-gas phase transition is found to be (17 ± 2) MeV, which is significantly larger than the temperature of fragmenting system (5 - 6 MeV). This is a very important observation in favour of the mechanism of spinodal disintegration. - It is concluded that the decay process of hot nuclei is characterized by two size parameters: transition state and freeze-out volumes. The IMF emission time is related to the mean rupture time at the multi-scission point, which corresponds to the kinetic freeze-out configuration. (author)
Open charm tomography of cold nuclear matter
Vitev, I; Johnson, M B; Qiu, J W
2006-01-01
We study the relative contribution of partonic sub-processes to D meson production and D meson-triggered inclusive di-hadrons to lowest order in perturbative QCD. While gluon fusion dominates the creation of large angle DD-bar pairs, charm on light parton scattering determines the yield of single inclusive D mesons. The distinctly different non-perturbative fragmentation of c quarks into D mesons versus the fragmentation of quarks and gluons into light hadrons results in a strong transverse momentum dependence of anticharm content of the away-side charm-triggered jet. In p+A reactions, we calculate and resum the coherent nuclear-enhanced power corrections from the final state partonic scattering in the medium. We find that single and double inclusive open charm production can be suppressed as much as the yield of neutral pions from dynamical high-twist shadowing. Effects of energy loss in p+A collisions are also investigated phenomenologically and may lead to significantly weaker transverse momentum dependenc...
Discrete wave-packet representation in nuclear matter calculations
Müther, H.; Rubtsova, O. A.; Kukulin, V. I.; Pomerantsev, V. N.
2016-08-01
The Lippmann-Schwinger equation for the nucleon-nucleon t matrix as well as the corresponding Bethe-Goldstone equation to determine the Brueckner reaction matrix in nuclear matter are reformulated in terms of the resolvents for the total two-nucleon Hamiltonians defined in free space and in medium correspondingly. This allows one to find solutions at many energies simultaneously by using the respective Hamiltonian matrix diagonalization in the stationary wave-packet basis. Among other important advantages, this approach simplifies greatly the whole computation procedures both for the coupled-channel t matrix and the Brueckner reaction matrix. Therefore this principally novel scheme is expected to be especially useful for self-consistent nuclear matter calculations because it allows one to accelerate in a high degree single-particle potential iterations. Furthermore the method provides direct access to the properties of possible two-nucleon bound states in the nuclear medium. The comparison between reaction matrices found via the numerical solution of the Bethe-Goldstone integral equation and the straightforward Hamiltonian diagonalization shows a high accuracy of the method suggested. The proposed fully discrete approach opens a new way to an accurate treatment of two- and three-particle correlations in nuclear matter on the basis of the three-particle Bethe-Faddeev equation by an effective Hamiltonian diagonalization procedure.
Initial-state splitting kernels in cold nuclear matter
Ovanesyan, Grigory; Ringer, Felix; Vitev, Ivan
2016-09-01
We derive medium-induced splitting kernels for energetic partons that undergo interactions in dense QCD matter before a hard-scattering event at large momentum transfer Q2. Working in the framework of the effective theory SCETG, we compute the splitting kernels beyond the soft gluon approximation. We present numerical studies that compare our new results with previous findings. We expect the full medium-induced splitting kernels to be most relevant for the extension of initial-state cold nuclear matter energy loss phenomenology in both p+A and A+A collisions.
Gap bridging enhancement of modified Urca process in nuclear matter
Alford, Mark G
2016-01-01
In nuclear matter at neutron-star densities and temperatures, Cooper pairing leads to the formation of a gap in the nucleon excitation spectra resulting in exponentially strong Boltzmann suppression of many transport coefficients. Previous calculations have shown evidence that density oscillations of sufficiently large amplitude can overcome this suppression for flavor-changing beta processes, via the mechanism of "gap bridging". We address the simplifications made in that initial work, and show that gap bridging can counteract Boltzmann suppression of neutrino emissivity for the realistic case of modified Urca processes in matter with $^3P_2$ neutron pairing.
Relativistic mean-field hadronic models under nuclear matter constraints
Dutra, M.; Lourenço, O.; Avancini, S. S.; Carlson, B. V.; Delfino, A.; Menezes, D. P.; Providência, C.; Typel, S.; Stone, J. R.
2014-11-01
Background: The microscopic composition and properties of infinite hadronic matter at a wide range of densities and temperatures have been subjects of intense investigation for decades. The equation of state (EoS) relating pressure, energy density, and temperature at a given particle number density is essential for modeling compact astrophysical objects such as neutron stars, core-collapse supernovae, and related phenomena, including the creation of chemical elements in the universe. The EoS depends not only on the particles present in the matter, but, more importantly, also on the forces acting among them. Because a realistic and quantitative description of infinite hadronic matter and nuclei from first principles in not available at present, a large variety of phenomenological models has been developed in the past several decades, but the scarcity of experimental and observational data does not allow a unique determination of the adjustable parameters. Purpose: It is essential for further development of the field to determine the most realistic parameter sets and to use them consistently. Recently, a set of constraints on properties of nuclear matter was formed and the performance of 240 nonrelativistic Skyrme parametrizations was assessed [M. Dutra et al., Phys. Rev. C 85, 035201 (2012), 10.1103/PhysRevC.85.035201] in describing nuclear matter up to about three times nuclear saturation density. In the present work we examine 263 relativistic-mean-field (RMF) models in a comparable approach. These models have been widely used because of several important aspects not always present in nonrelativistic models, such as intrinsic Lorentz covariance, automatic inclusion of spin, appropriate saturation mechanism for nuclear matter, causality, and, therefore, no problems related to superluminal speed of sound in medium. Method: Three different sets of constraints related to symmetric nuclear matter, pure neutron matter, symmetry energy, and its derivatives were used. The
Appearance of the Gyroid Network Phase in Nuclear Pasta Matter
Schuetrumpf, B; Iida, K; Schroeder-Turk, G E; Maruhn, J A; Mecke, K; Reinhard, P -G
2014-01-01
Nuclear matter under the conditions of a supernova explosion unfolds into a rich variety of spatially structured phases, called nuclear pasta. We investigate the role of periodic networklike structures with negatively curved interfaces in nuclear pasta structures, by static and dynamic Hartree-Fock simulations in periodic lattices. We investigate particularly the role of minimal surfaces in that context. As the most prominent result, we identify the single gyroid network structure of cubic chiral symmetry, a well known configuration in nanostructured softmatter systems, both as a dynamical state and as a cooled static solution. While most observed gyroids are only meta-stable, the very small energy differences to the ground state indicate its relevance for structures in nuclear pasta.
Density isomer of nuclear matter in an equivalent mass approach
International Nuclear Information System (INIS)
The equation of state of symmetric nuclear matter is studied with an equivalent mass model. The equivalent mass of a nucleon has been expanded to order 4 in density. We first determine the first-order expansion coefficient in the quantum hadron dynamics, then calculate the coefficients of the second to fourth order for the given binding energy and incompressibility at the normal nuclear saturation density., It is found that there appears a density. isomeric state if the incompressibility is smaller than a critical value. The model dependence of the conclusion has also been checked by varying the first-order coefficient. (authors)
Chiral symmetry and nuclear matter equation of state
Indian Academy of Sciences (India)
A B Santra
2001-08-01
We investigate the effect on the nuclear matter equation of state (EOS) due to modiﬁcation of meson and nucleon parameters in nuclear medium as a consequence of partial restoration of chiral symmetry. To get the EOS, we have used Brueckner–Bethe–Golstone formalism with Bonn- potential as two-body interaction and QCD sum rule and Brown–Rho scaling prescriptions for modiﬁcation of hadron parameters. We ﬁnd that EOS is very much sensitive to the meson parameters. We can ﬁt, with two body interaction alone, both the saturation density and the binding energy per nucleon.
Finite size effects in Neutron Star and Nuclear matter simulations
Molinelli, P A Giménez
2014-01-01
In this work we study molecular dynamics simulations of symmetric nuclear matter using a semi-classical nucleon interaction model. We show that, at sub-saturation densities and low temperatures, the solutions are non-homogeneous structures reminiscent of the ``nuclear pasta'' phases expected in Neutron Star Matter simulations, but shaped by artificial aspects of the simulations. We explore different geometries for the periodic boundary conditions imposed on the simulation cell: cube, hexagonal prism and truncated octahedron. We find that different cells may yield different solutions for the same physical conditions (i.e. density and temperature). The particular shape of the solution at a given density can be predicted analytically by energy minimization. We also show that even if this behavior is due to finite size effects, it does not mean that it vanishes for very large systems and it actually is independent of the system size: The system size sets the only characteristic length scale for the inhomogeneitie...
Pure Neutron Matter Constraints and Nuclear Symmetry Energy
International Nuclear Information System (INIS)
In this review, we will discuss the results of our recent work [1] to study the general optimization of the pure isovector parameters of the popular relativistic mean-field (RMF) and Skyrme-Hartree-Fock (SHF) nuclear energy-density functionals (EDFs), using constraints on the pure neutron matter (PNM) equation of state (EoS) from recent ab initio calculations. By using RMF and SHF parameterizations that give equivalent predictions for ground-state properties of doubly magic nuclei and properties of symmetric nuclear matter (SNM) and PNM, we found that such optimization leads to broadly consistent symmetry energy J and its slope parameter L at saturation density within a tight range of α(J) sym, (b) the symmetry energy at supra-saturation densities, and (c) the radius of neutron stars.
Compression modes and the nuclear matter incompressibility coefﬁcient
Indian Academy of Sciences (India)
Shalom Shlomo
2001-08-01
We review the current status of the nuclear matter ( = and no Coulomb interaction) incompressibility coefﬁcient, , and describe the theoretical and the experimental methods used to determine from properties of compression modes in nuclei. In particular we consider the long standing problem of the conﬂicting results obtained for , deduced from experimental data on excitation cross sections for the isoscalar giant monopole resonance (ISGMR) and data for the isoscalar giant dipole resonance (ISGDR).
Investigation of the organic matter in inactive nuclear tank liquids
Energy Technology Data Exchange (ETDEWEB)
Schenley, R.L.; Griest, W.H.
1990-08-01
Environmental Protection Agency (EPA) methodology for regulatory organics fails to account for the organic matter that is suggested by total organic carbon (TOC) analysis in the Oak Ridge National Laboratory (ORNL) inactive nuclear waste-tank liquids and sludges. Identification and measurement of the total organics are needed to select appropriate waste treatment technologies. An initial investigation was made of the nature of the organics in several waste-tank liquids. This report details the analysis of ORNL wastes.
Heating of nuclear matter and multifragmentation: antiprotons vs. pions
International Nuclear Information System (INIS)
Heating of nuclear matter with 8 GeV/c bar p and π- beams has been investigated in an experiment conducted at BNL AGS accelerator. All charged particles from protons to Z ≅ 16 were detected using the Indiana Silicon Sphere 4π array. Significant enhancement of energy deposition in high multiplicity events is observed for antiprotons compared to other hadron beams. The experimental trends are qualitatively consistent with predictions from an intranuclear cascade code
Conventional and Unconventional Pairing and Condensates in Dilute Nuclear Matter
Clark, John W; Sedrakian, Armen; Stein, Martin; Huang, Xu-Guang; Khodel, Victor A; Shaginyan, Vasily R.; Zverev, Mikhail V
2016-01-01
This contribution will survey recent progress toward an understanding of diverse pairing phenomena in dilute nuclear matter at small and moderate isospin asymmetry, with results of potential relevance to supernova envelopes and proto-neutron stars. Application of {\\it ab initio} many-body techniques has revealed a rich array of temperature-density phase diagrams, indexed by isospin asymmetry, which feature both conventional and unconventional superfluid phases. At low density there exist a ho...
Three- and Four-body correlations in nuclear matter
Beyer, M.
2001-01-01
Few-nucleon correlations in nuclear matter at finite densities and temperatures are explored. Using the Dyson equation approach leads to effective few-body equations that include self energy corrections and Pauli blocking factors in a systematic way. Examples given are the nucleon deuteron in-medium reaction rates, few-body bound states including the $\\ga$-particle, and $\\ga$-particle condensation.
Pauli exclusion operator and binding energy of nuclear matter
Schiller, E.; Müther, H; Czerski, P.
1998-01-01
Brueckner-Hartree-Fock calculations are performed for nuclear matter with an exact treatment of the Pauli exclusion operator in the Bethe-Goldstone equation. The differences in the calculated binding energy, compared to the angle-average approximation, which is commonly used, are non-negligible. These difference exhibits a specific density dependence, which shifts the calculated saturation point towards smaller densities. This effect is observed for various versions of modern models for the N...
Investigation of the organic matter in inactive nuclear tank liquids
International Nuclear Information System (INIS)
Environmental Protection Agency (EPA) methodology for regulatory organics fails to account for the organic matter that is suggested by total organic carbon (TOC) analysis in the Oak Ridge National Laboratory (ORNL) inactive nuclear waste-tank liquids and sludges. Identification and measurement of the total organics are needed to select appropriate waste treatment technologies. An initial investigation was made of the nature of the organics in several waste-tank liquids. This report details the analysis of ORNL wastes
Isovector collective response function of nuclear matter at finite temperature
International Nuclear Information System (INIS)
We study isovector collective excitations in nuclear matter by employing the linearized Landau–Vlasov equation with and without a non-Markovian binary collision term at finite temperature. We calculate the giant dipole resonance (GDR) strength function for finite nuclei using the Steinwedel–Jensen model and also by Thomas–Fermi approximation, and we compare them for 120Sn and 208Pb with experimental results. (author)
Relativistic spectral function of nucleon in hot nuclear matter
Ghosh, Sabyasachi; Mallik, S.; Sarkar, Sourav
2010-01-01
We present a simple calculation of the nucleon self-energy in nuclear matter at finite temperature in a relativistic framework, using the real time thermal field theory. The imaginary parts of one-loop graphs are identified with discontinuities across the unitary and the Landau cuts. We find that in general both the cuts contribute significantly to the spectral function in the region of (virtual) nucleon mass usually considered, even though the unitary cut is ignored in the literature. Also o...
Single particle spectrum and binding energy of nuclear matter
Baldo, M; Fiasconaro, A.
2000-01-01
In non-relativistic Brueckner calculations of nuclear matter, the self-consistent single particle potential is strongly momentum dependent. To simplify the calculations, a parabolic approximation is often used in the literature. The variation in the binding energy value introduced by the parabolic approximation is quantitatively analyzed in detail. It is found that the approximation can introduce an uncertainty of 1-2 MeV near the saturation density.
The Landau parameters of nuclear matter in relativistic Hartree approximation
International Nuclear Information System (INIS)
The Landau parameters of nuclear matter have been calculated in relativistic Hartree approximation as a function of a renormalization scale. The results have then been compared to the empirical values deduced from constraints on isoscalar compression modes, spin-orbit splitting in nuclei and energy dependence of the nucleon-nucleus optical potential. For comparison, the results obtained for relativistic non-linear models and Dirac-Brueckner-Hartree-Fock calculations are also shown. (author)
Pauli Exclusion Operator and Binding Energy of Nuclear Matter
International Nuclear Information System (INIS)
Full text: Brueckner-Hartree-Fock calculations are performed for nuclear matter with an exact treatment of the Pauli exclusion operator in the Bethe-Goldstone equation. The differences in the calculated binding energy, compared to the angle-average approximation, which is commonly used, are non-negligible. These difference exhibits a specific density dependence, which shifts the calculated saturation point towards smaller densities. This effect is observed for various versions of modern models for the NN interaction. (author)
Updated constraints on velocity and momentum-dependent asymmetric dark matter
Vincent, Aaron C; Serenelli, Aldo
2016-01-01
We present updated constraints on dark matter models with momentum-dependent or velocity-dependent interactions with nuclei, based on direct detection and solar physics. We improve our previous treatment of energy transport in the solar interior by dark matter scattering, leading to significant changes in fits to many observables. Based on solar physics alone, DM with a spin-independent $q^{4}$ coupling provides the best fit to data, and a statistically satisfactory solution to the solar abundance problem. Once direct detection limits are accounted for however, the best solution is spin-dependent $v^2$ scattering with a reference cross-section of 10$^{-35}$ cm$^2$ (at a reference velocity of $v_0=220$ km s$^{-1}$), and a dark matter mass of about 5 GeV.
On the Origin of the Charge-Asymmetric Matter. II. Localized Dirac Waveforms
Makhlin, Alexander
2016-01-01
This paper continues the author's work \\cite{PartI}, where a new framework of the matter-induced physical geometry was built and an intrinsic nonlinearity of the Dirac equation discovered. Here, the nonlinear Dirac equation is solved and the localized configurations are found analytically. Of the two possible types of the potentially stationary localized configurations of the Dirac field, only one is stable with respect to the action of an external field and it corresponds to a positive charge. A connection with the global charge asymmetry of matter in the Universe and with the recently observed excess of the cosmic positrons is discussed.
Separable NN potentials from inverse scattering for nuclear matter studies
International Nuclear Information System (INIS)
Low-rank separable potentials greatly simplify perturbation-theory based many-body computations and are especially useful in finite temperature and nonequilibrium nuclear matter studies. With local potentials such calculations become very lengthy. In this paper, we present a first version of a separable potential constructed directly from available empirical nucleon-nucleon phase shifts (Elab3S1-3D1 channel, where the deuteron wave function serves as off-shell input at the binding energy. The simplest potential thus constructed in this channel has rank 4. The deuteron wave function is nevertheless empirically undetermined at high momenta, prompting us to adopt as well as construct several model wave functions that all fit the low momentum deuteron data while allowing variations at high momenta. The effects of these off-shell variations on predicted nuclear matter properties are discussed. No off-shell information is included in the other channels, leading to potentials of rank either 1 or 2. With this simple model potential we perform standard Brueckner nuclear matter ground state calculations and compare the results with Machleidt's using Bonn OBEP. The agreement is good in the S channels and in the singlet D2 channel. Other channels show larger discrepancies, the most significant of which coming from the 3P1 and 3D1 channels. These results are explained by the off-shell behavior of our model potential as compared to the Bonn OBEP. (Abstract Truncated)
Some Properties of πr Meson in Nuclear Matter with Finite Density
Institute of Scientific and Technical Information of China (English)
YANG Lan-Fei; Lu Xiao-Fu
2002-01-01
In the GCM we study some properties of π meson as the Goldstone bosons in a nuclear matter with finitedensity. Using the effective action in a nuclear matter, we calculate the decay constant and π mass as functions of thechemical potential. The relation between the chemical potential and the density of a nuclear matter is firstly given here.We find that fπ and mπ monotonously decrease as nuclear matter density increases. The result is consistent with theusual assumption that the chiral symmetry is gradually restored as the density of a nuclear matter increases.
Some Properties of π Meson in Nuclear Matter with Finite Density
Institute of Scientific and Technical Information of China (English)
YANGLan－Fei; LUXiao－Fu
2002-01-01
In the GCM we study some properties of π meson as the Goldstone bosons in a nuclear matter with finite density.Using the effective action in a nuclear matter,we calculate the decay constant and π mass as functions of the chemical potential.The relation between the chemical potential and the density of a nuclear matter is firstly given here.We find that fπ and mπ monotonously decrease as nuclear matter density increases.The result is consistent with the usual assumption that the chiral symmetry is gradually restored as the density of a nuclear matter increases.
Finite size effects in neutron star and nuclear matter simulations
Energy Technology Data Exchange (ETDEWEB)
Giménez Molinelli, P.A., E-mail: pagm@df.uba.ar; Dorso, C.O.
2015-01-15
In this work we study molecular dynamics simulations of symmetric nuclear and neutron star matter using a semi-classical nucleon interaction model. Our aim is to gain insight on the nature of the so-called “finite size effects”, unavoidable in this kind of simulations, and to understand what they actually affect. To do so, we explore different geometries for the periodic boundary conditions imposed on the simulation cell: cube, hexagonal prism and truncated octahedron. For nuclear matter simulations we show that, at sub-saturation densities and low temperatures, the solutions are non-homogeneous structures reminiscent of the “nuclear pasta” phases expected in neutron star matter simulations, but only one structure per cell and shaped by specific artificial aspects of the simulations—for the same physical conditions (i.e. number density and temperature) different cells yield different solutions. The particular shape of the solution at low enough temperature and a given density can be predicted analytically by surface minimization. We also show that even if this behavior is due to the imposition of periodic boundary conditions on finite systems, this does not mean that it vanishes for very large systems, and it is actually independent of the system size. We conclude that, for nuclear matter simulations, the cells' size sets the only characteristic length scale for the inhomogeneities, and the geometry of the periodic cell determines the shape of those inhomogeneities. To model neutron star matter we add a screened Coulomb interaction between protons, and perform simulations in the three cell geometries. Our simulations indeed produce the well known nuclear pasta, with (in most cases) several structures per cell. However, we find that for systems not too large results are affected by finite size in different ways depending on the geometry of the cell. In particular, at the same certain physical conditions and system size, the hexagonal prism yields a
Superconducting Nuclear Recoil Sensor for Directional Dark Matter Detection
Junghans, Ann; Baldwin, Kevin; Hehlen, Markus; Lafler, Randy; Loomba, Dinesh; Phan, Nguyen; Weisse-Bernstein, Nina
The Universe consists of 72% dark energy, 23% dark matter and only 5% of ordinary matter. One of the greatest challenges of the scientific community is to understand the nature of dark matter. Current models suggest that dark matter is made up of slowly moving, weakly interacting massive particles (WIMPs). But detecting WIMPs is challenging, as their expected signals are small and rare compared to the large background that can mimic the signal. The largest and most robust unique signature that sets them apart from other particles is the day-night variation of the directionality of dark matter on Earth. This modulation could be observed with a direction-sensitive detector and hence, would provide an unambiguous signature for the galactic origin of WIMPs. There are many studies underway to attempt to detect WIMPs both directly and indirectly, but solid-state WIMP detectors are widely unexplored although they would present many advantages to prevalent detectors that use large volumes of low pressure gas. We present first results of a novel multi-layered architecture, in which WIMPs would interact primarily with solid layers to produce nuclear recoils that then induce measureable voltage pulses in adjacent superconductor layers. This work was supported by the U.S. Department of Energy through the LANL Laboratory Directed Research and Development Program.
Nuclear Transparency Effect in the Strongly Interacting Matter
Ajaz, M; Abdinov, O B; Zaman, Ali; Khan, K H; Wazir, Z; Khalilova, Sh
2012-01-01
We discuss that the results of study of the nuclear transparency effect in nuclear-nuclear collisions at relativistic and ultrarelativistic energies could help to extract the information on new phases of the strongly interacting matter as well as the QCD critical point. The results could provide further confirmation of the existence of the "horn" effect which had initially been obtained for the ratio of average values of K+ to pi+ -mesons' multiplicity as a function of the initial energies in the NA49 SPS CERN experiment. To observe the "horn" as a function of centrality, the new more enriched experimental data are required. The data which are expected from NICA/MPD JINR and CBM GSI setups could fulfill the requirement.
Dark Matter Particle Spectroscopy at the LHC: Generalizing MT2 to Asymmetric Event Topologies
Konar, Partha; Matchev, Konstantin T; Park, Myeonghun
2009-01-01
We consider SUSY-like missing energy events at hadron colliders and critically examine the common assumption that the missing energy is the result of two identical missing particles. In order to experimentally test this hypothesis, we generalize the subsystem MT2 variable to the case of asymmetric event topologies, where the two SUSY decay chains terminate in different "children" particles. In this more general approach, the endpoint MT2max of the MT2 distribution now gives the mass Mp(Mc(a),Mc(b)) of the parent particle as a function of two input children masses Mc(a) and Mc(b). We propose two methods for an independent determination of the individual children masses Mc(a) and Mc(b). First, in the presence of upstream transverse momentum P(UTM) the corresponding function Mp(Mc(a),Mc(b),P(UTM)) is independent of P(UTM) at precisely the right values of the children masses. Second, the previously discussed MT2 "kink" is now generalized to a "ridge" on the 2-dimensional surface Mp(Mc(a),Mc(b)). As we show in sev...
Relativistic mean-field models and nuclear matter constraints
Energy Technology Data Exchange (ETDEWEB)
Dutra, M.; Lourenco, O.; Carlson, B. V. [Departamento de Fisica, Instituto Tecnologico de Aeronautica-CTA, 12228-900, Sao Jose dos Campos, SP (Brazil); Delfino, A. [Instituto de Fisica, Universidade Federal Fluminense, 24210-150, Boa Viagem, Niteroi, RJ (Brazil); Menezes, D. P.; Avancini, S. S. [Departamento de Fisica, CFM, Universidade Federal de Santa Catarina, CP. 476, CEP 88.040-900, Florianopolis, SC (Brazil); Stone, J. R. [Oxford Physics, University of Oxford, OX1 3PU Oxford (United Kingdom) and Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996 (United States); Providencia, C. [Centro de Fisica Computacional, Department of Physics, University of Coimbra, P-3004-516 Coimbra (Portugal); Typel, S. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Theorie, Planckstrasse 1,D-64291 Darmstadt (Germany)
2013-05-06
This work presents a preliminary study of 147 relativistic mean-field (RMF) hadronic models used in the literature, regarding their behavior in the nuclear matter regime. We analyze here different kinds of such models, namely: (i) linear models, (ii) nonlinear {sigma}{sup 3}+{sigma}{sup 4} models, (iii) {sigma}{sup 3}+{sigma}{sup 4}+{omega}{sup 4} models, (iv) models containing mixing terms in the fields {sigma} and {omega}, (v) density dependent models, and (vi) point-coupling ones. In the finite range models, the attractive (repulsive) interaction is described in the Lagrangian density by the {sigma} ({omega}) field. The isospin dependence of the interaction is modeled by the {rho} meson field. We submit these sets of RMF models to eleven macroscopic (experimental and empirical) constraints, used in a recent study in which 240 Skyrme parametrizations were analyzed. Such constraints cover a wide range of properties related to symmetric nuclear matter (SNM), pure neutron matter (PNM), and both SNM and PNM.
The Two-Pion Exchange NN-Potential in Nuclear Matter and Nuclear Stability
Rapp, R.; Durso, J.W.; Wambach, J.
1996-01-01
A meson exchange model of the $\\pi\\pi$ interaction which fits free $\\pi\\pi$ scattering data is used to calculate the interactions of pions in nuclear matter as a function of nuclear density. Polarization of the nuclear medium by the pions results in a marked increase in the s-wave $\\pi\\pi$ attraction at low energy. The influence of this effect on the nucleon-nucleon interaction is a corresponding increase with density of the $NN$ central potential due to the exchange of two correlated pions, ...
Converting of Matter to Nuclear Energy by AB-Generator
Directory of Open Access Journals (Sweden)
Alexander Bolonkin
2009-01-01
Full Text Available Problem statement: Researcher offered a new nuclear generator which allowed to convert any matter to nuclear energy in accordance with Einstein equation E = mc2. The method was based upon tapping the energy potential of a Micro Black Hole (MBH and Hawking radiation created by this MBH. Researcher did not meet the idea and its research in literature to develop the method for getting a cheap energy. Approach: As is well-known, vacuum continuously produced virtual pairs of particles and antiparticles, in particular, photons and anti-photons. MBH event horizon allowed separating them. Anti-photons can be moved to MBH and be annihilated, decreasing mass of MBH, resulting photons leave the MBH neighborhood as Hawking radiation. The offered nuclear generator (named by Researcher as AB-generator utilized Hawking radiation and injected the matter into MBH and kept MBH in a stable state with near-constant mass. Results: AB-generator can be produced gigantic energy outputs and should be cheaper than a conventional electric station by a factor of hundreds of times. One also may be used in aerospace as a photon rocket or as a power source for many vehicles. Conclusion: Many scientists expect Large Hadron Collider at CERN may be produced one MBH every second. A technology to capture them may be developed; than they may be used for the AB-generator.
Conventional and Unconventional Pairing and Condensates in Dilute Nuclear Matter
Clark, John W; Stein, Martin; Huang, Xu-Guang; Khodel, Victor A; Shaginyan, Vasily R; Zverev, Mikhail V
2016-01-01
This contribution will survey recent progress toward an understanding of diverse pairing phenomena in dilute nuclear matter at small and moderate isospin asymmetry, with results of potential relevance to supernova envelopes and proto-neutron stars. Application of {\\it ab initio} many-body techniques has revealed a rich array of temperature-density phase diagrams, indexed by isospin asymmetry, which feature both conventional and unconventional superfluid phases. At low density there exist a homogeneous translationally invariant BCS phase, a homogeneous LOFF phase violating translational invariance, and an inhomogeneous translationally invariant phase-separated BCS phase. The transition from the BCS to the BEC phases is characterized in terms of the evolution, from weak to strong coupling, of the pairing gap, condensate wave function, and quasiparticle occupation numbers and spectra. Additionally, a schematic formal analysis of pairing in neutron matter at low to moderate densities is presented that establishes...
Extraction of Nuclear Matter Properties from Nuclear Masses by a Model of Equation of State
Institute of Scientific and Technical Information of China (English)
K.C.Chung; C.S.Wang; A.J.Santiago
2001-01-01
The extraction of nuclear matter properties from measured nuclear masses is investigated in the energy density functional formalism of nuclei.It is shown that the volume energy a1 and the nuclear incompressibility Ko depend essentially on μnN -+- pZ - 2EN,whereas the symmetry energy J and the density symmetry coefficient L as well as symmetry incompressibility Ks depend essentially on μn - μp,where μp ＝μp - Ec/ Z,μn and μp are the neutron and proton chemical potentials respectively,EN the nuclear energy,and Ec the Coulomb energy.The obtained symmetry energy is J ＝ 28.5 MeV,while other coefficients are uncertain within ranges depending on the model of nuclear equation of state.``
Alam, N; Fortin, M; Pais, H; Providência, C; Raduta, Ad R; Sulaksono, A
2016-01-01
We examine the correlations of neutron star radii with the nuclear matter incompressibility, symmetry energy, and their slopes, which are the key parameters of the equation of state (EoS) of asymmetric nuclear matter. The neutron star radii and the EoS parameters are evaluated using a representative set of 24 Skyrme-type effective forces and 18 relativistic mean field models, and two microscopic calculations, all describing 2$M_\\odot$ neutron stars. Unified EoSs for the inner-crust-core region have been built for all the phenomenological models, both relativistic and non-relativistic. Our investigation shows the existence of a strong correlation of the neutron star radii with the linear combination of the slopes of the nuclear matter incompressibility and the symmetry energy coefficients at the saturation density. Such correlations are found to be almost independent of the neutron star mass in the range $0.6\\text{-}1.8M_{\\odot}$. This correlation can be linked to the empirical relation existing between the st...
Sakuragi, Y
2016-01-01
Yoichiro Nambu put a great foot print in nuclear physics in the era of its fundamental developments including his pioneering insight into essential ingredients of repulsive core of nuclear force and its relation to the saturation of nuclear matter. The present review article focuses onto recent developments of the interaction models between colliding nuclei in terms of Brueckner's G-matrix theory staring from realistic nuclear forces and the saturation property of symmetric nuclear matter as well as neutron-star matter. A recently proposed unique scenario of extracting the saturation property of nuclear matter and stiffness of neutron stars through the analysis of nucleus-nucleus elastic scattering in laboratories is presented in some detail.
2010-03-09
... From the Federal Register Online via the Government Publishing Office NUCLEAR REGULATORY COMMISSION In the Matter of Entergy Nuclear Operations; Vermont Yankee Nuclear Power Station; Demand for.... The license authorizes the operation of the Vermont Yankee Nuclear Power Station (Vermont Yankee)...
Model-space nuclear matter calculations with the Bonn potential
Energy Technology Data Exchange (ETDEWEB)
Engvik, L.; Hjort-Jensen, M.; Osnes, E.; Kuo, T.T.S.
1992-08-01
In this work the authors have examined a model-space Brueckner-Hartree-Fock (MBHF) approach to the single-particle energies in nuclear matter, employing three recent versions of the Bonn meson-exchange potential model. The non-relativistic MBHF calculations form the well known ''Coester'' band, where the potential which exhibits the weakest tensor force yields the largest binding energy per nucleon. Correcting for relativistic effects, the MBHF calculations result in too little binding. The implications are discussed. 12 refs., 2 figs.
Model-space nuclear matter calculations with the Bonn potential
Energy Technology Data Exchange (ETDEWEB)
Engvik, L.; Hjort-Jensen, M.; Osnes, E.; Kuo, T.T.S.
1992-08-01
In this work the authors have examined a model-space Brueckner-Hartree-Fock (MBHF) approach to the single-particle energies in nuclear matter, employing three recent versions of the Bonn meson-exchange potential model. The non-relativistic MBHF calculations form the well known ``Coester`` band, where the potential which exhibits the weakest tensor force yields the largest binding energy per nucleon. Correcting for relativistic effects, the MBHF calculations result in too little binding. The implications are discussed. 12 refs., 2 figs.
Nuclear matter equation of state and -meson parameters
Indian Academy of Sciences (India)
A B Santra; U Lambardo
2005-01-01
We try to determine phenomenologically the extent of in-medium modification of -meson parameters so that the saturation observables of the nuclear matter equation of state (EOS) are reproduced. To calculate the EOS we have used Brueckner–Bethe–Goldstone formalism with Bonn potential as two-body interaction. We find that it is possible to understand all the saturation observables, namely, saturation density, energy per nucleon and incompressibility, by incorporating in-medium modification of -meson–nucleon coupling constant and -meson mass by a few per cent.
Mass shift of σ-meson in nuclear matter
International Nuclear Information System (INIS)
The propagation of σ-meson in nuclear matter is studied in the Walecka model, by assuming that sigma couples to a pair of nucleon-antinucleon states to particle-hole states. The in-medium effect of σ-ω mixing is also studied. For completeness, the coupling of sigma to two virtual pions was also considered. It is found that the σ-meson mass decreases with respect to its value in vacuum and that the contribution of the σ-ω mixing effect on the mass shift is relatively small. (author)
Shear viscosity of $\\beta$-stable nuclear matter
Benhar, Omar
2009-01-01
Viscosity plays a critical role in determining the stability of rotating neutron stars. We report the results of a calculation of the shear viscosity of $\\beta$~-~stable matter, carried out using an effective interaction based on a state-of-the-art nucleon-nucleon potential and the formalism of correlated basis functions. Within our approach the equation of state, determining the proton fraction, and the nucleon-nucleon scattering probability are consistently obtained from the same dynamical model. The results show that, while the neutron contribution to the viscosity is always dominant, above nuclear saturation density the electron contribution becomes appreciable.
Dark matter searches employing asymmetric velocity distributions obtained via the Eddington approach
Vergados, J. D.; Moustakidis, Ch. C.; Owen, D.
2016-08-01
Starting from WIMP density profiles, in the framework of the Eddington approach, we obtain the energy distribution f(E) of dark matter in our vicinity. Assuming a factorizable phase space function, f(E , L) = F(E) FL(L) , we obtain the velocity dispersions and the anisotropy parameter β in terms of the parameters describing the angular momentum dependence. By employing the derived expression f(E) we construct axially symmetric WIMP velocity distributions. The obtained distributions automatically have a velocity upper bound, as a consequence of the fact that they are associated with a gravitationally bound system, and are characterized by an anisotropy parameter β. We then show how such velocity distributions can be used in determining the event rates, including modulation, both in the standard as well directional WIMP searches.
Exponential enhancement of nuclear reactions in condensed matter environment
Kuchiev, M Yu; Flambaum, V V
2003-01-01
A mechanism that uses the environment to enhance the probability of the nuclear reaction when a beam of accelerated nuclei collides with a target nucleus implanted in condensed matter is suggested. The effect considered is exponentially large for low collision energies. For t + p collision the mechanism becomes effective when the energy of the projectile tritium is below $\\sim$ 1 Kev per nucleon. The gain in probability of the nuclear reaction is due to a redistribution of energy and momentum of the projectile in several ``preliminary'' elastic collisions with the target nucleus and the environmental nuclei in such a way that the final inelastic projectile-target collision takes place at a larger relative velocity, which is accompanied by a decrease of the center of mass energy. The gain of the relative velocity exponentially increases the penetration through the Coulomb barrier.
Nuclear matter at finite temperature and density: theory and experiment
International Nuclear Information System (INIS)
The consequences of a phase transition associated with symmetry restoration to SU(2) x SU(2) in nuclear matter are investigated. The changes in the mass spectrum due to the phase transition (a) at zero temperature and high density, and (b) at high temperature with zero chemical potential are evaluated in the sigma model of particle physics. The experimentally observable effects necessitate the measurement of current correlation functions. In this thesis, the Vector-Vector-Axial vector (VVA) and the Vector-Vector-Pseudoscalar (VVP) current correlation functions are evaluated. The VVP correlation function is related to the neutral-pion decay amplitude. The changes in the decay rate of π0 → 2γ in the nuclear medium are evaluated by including the effects of changes in the mass spectrum of particles, and by using the cutting rules of many-body field theory for the real and imaginary parts of the amplitude. The changes in the mass spectrum due to symmetry restoration affect the decay rate of π0 → 2γ by at least two orders of magnitude and these results are tabulated. The Primakoff effect (γ + 'γ' → π0) is proposed as a means of providing the signal for the abnormal phase. An expression for the Primakoff differential cross section is derived taking into account nuclear absorption effects, the nonuniform nuclear density, and a background contribution arising from strong coherent nuclear processes. Finally, the new field of relativistic nuclear fragmentation is introduced. A phenomenological analysis of recent FNAL data involving proton-nucleus collisions (E591) is carried out
Directory of Open Access Journals (Sweden)
Wolniak Stephen M
2011-10-01
Full Text Available Abstract Background Many rapidly developing systems rely on the regulated translation of stored transcripts for the formation of new proteins essential for morphogenesis. The microspores of the water fern Marsilea vestita dehydrate as they mature. During this process both mRNA and proteins required for subsequent development are stored within the microspores as they become fully desiccated and enter into senescence. At this point microspores become transcriptionally silent and remain so upon rehydration and for the remainder of spermatogenesis. Transcriptional silencing coupled with the translation of preformed RNA makes the microspore of M. vestita a useful system in which to study post-transcriptional regulation of RNA. Results We have characterized the distribution of mRNA as well as several conserved markers of subnuclear bodies within the nuclei of desiccating spores. During this period, nuclear speckles containing RNA were seen to aggregate forming a single large coalescence. We found that aggregated speckles contain several masked mRNA species known to be essential for spermatogenesis. During spermatogenesis masked mRNA and associated speckle proteins were shown to fragment and asymmetrically localize to spermatogenous but not sterile cells. This asymmetric localization was disrupted by RNAi knockdown of the Marsilea homolog of the Exon Junction Complex core component Mago nashi. Conclusions A subset of masked mRNA is stored in association with nuclear speckles during the dormant phase of microspore development in M. vestita. The asymmetric distribution of specific mRNAs to spermatogenous but not sterile cells mirrors their translational activities and appears to require the EJC or EJC components. This suggests a novel role for nuclear speckles in the post-transcriptional regulation of transcripts.
Negative-parity nucleon excited state in nuclear matter
Ohtani, Keisuke; Oka, Makoto
2016-01-01
Spectral functions of the nucleon and its negative parity excited state in nuclear matter are studied using QCD sum rules and the maximum entropy method (MEM). It is found that in-medium modifications of the spectral functions are attributed mainly to density dependencies of the $\\langle \\bar{q}q \\rangle $ and $\\langle q^{\\dagger}q \\rangle $ condensates. The MEM reproduces the lowest-energy peaks of both the positive and negative parity nucleon states at finite density up to $\\rho \\sim \\rho_N$ (normal nuclear matter density). As the density grows, the residue of the nucleon ground state decreases gradually while the residue of the lowest negative parity excited state increases slightly. On the other hand, the positions of the peaks, which correspond to the total energies of these states, are almost density independent for both parity states. The density dependencies of the effective masses and vector self-energies are also extracted by assuming the mean-field green functions for the peak states. We find that,...
Open heavy flavor in QCD matter and in nuclear collisions
Prino, Francesco; Rapp, Ralf
2016-09-01
We review the experimental and theoretical status of open heavy-flavor (HF) production in high-energy nuclear collisions at the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC). We first overview the theoretical concepts and pertinent calculations of HF transport in strong-interaction matter, including perturbative and non-perturbative approaches in quark-gluon plasma, effective models in hadronic matter, as well as implementations of heavy-quark (HQ) hadronization. This is followed by a brief discussion of bulk evolution models for heavy-ion collisions and initial conditions for the HQ distributions which are needed to calculate HF spectra in comparison to observables. We then turn to a discussion of experimental data that have been collected to date at RHIC and the LHC, specifically for the nuclear modification factor and elliptic flow of leptons from semileptonic HF decays, D mesons, non-prompt J/\\psi from B-meson decays, and b-jets. Model comparisons to HF data are conducted with regards to extracting the magnitude, temperature and momentum dependence of HF transport coefficients from experiment.
Open Heavy Flavor in QCD Matter and in Nuclear Collisions
Prino, Francesco
2016-01-01
We review the experimental and theoretical status of open heavy-flavor (HF) production in high-energy nuclear collisions at RHIC and LHC. We first overview the theoretical concepts and pertinent calculations of HF transport in QCD matter, including perturbative and non-perturbative approaches in the quark-gluon plasma, effective models in hadronic matter, as well as implementations of heavy-quark (HQ) hadronization. This is followed by a brief discussion of bulk evolution models for heavy-ion collisions and initial conditions for the HQ distributions which are needed to calculate HF spectra in comparison to observables. We then turn to a discussion of experimental data that have been collected to date at RHIC and LHC, specifically for the nuclear suppression factor and elliptic flow of semileptonic HF decays, D mesons, non-prompt $J/\\psi$ from B-meson decays, and b-jets. Model comparisons to HF data are conducted with regards to extracting the magnitude, temperature and momentum-dependence of HF transport coe...
Open heavy flavor in QCD matter and in nuclear collisions
Prino, Francesco; Rapp, Ralf
2016-09-01
We review the experimental and theoretical status of open heavy-flavor (HF) production in high-energy nuclear collisions at the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC). We first overview the theoretical concepts and pertinent calculations of HF transport in strong-interaction matter, including perturbative and non-perturbative approaches in quark–gluon plasma, effective models in hadronic matter, as well as implementations of heavy-quark (HQ) hadronization. This is followed by a brief discussion of bulk evolution models for heavy-ion collisions and initial conditions for the HQ distributions which are needed to calculate HF spectra in comparison to observables. We then turn to a discussion of experimental data that have been collected to date at RHIC and the LHC, specifically for the nuclear modification factor and elliptic flow of leptons from semileptonic HF decays, D mesons, non-prompt J/\\psi from B-meson decays, and b-jets. Model comparisons to HF data are conducted with regards to extracting the magnitude, temperature and momentum dependence of HF transport coefficients from experiment.
$D_S$ Mesons in Asymmetric Hot and Dense Hadronic Matter
Pathak, Divakar
2014-01-01
The in-medium properties of $D_S$ mesons are investigated within the framework of a chiral effective model. These are observed to experience net attractive interactions in a dense hadronic medium, hence reducing the masses of the $D_S^+$ and $D_S^-$ mesons from the vacuum values. While this conclusion holds in both nuclear and hyperonic media, the magnitude of the mass drop is observed to intensify with the inclusion of strangeness in the medium. Additionally, in hyperonic medium, the mass degeneracy of the $D_S$ mesons is observed to be broken, due to opposite signs of the Weinberg-Tomozawa interaction term in the Lagrangian density. Along with the magnitude of the mass drops, the mass splitting between $D_S^+$ and $D_S^-$ mesons is also observed to grow with an increase in baryonic density and strangeness content of the medium. However, all medium effects analyzed are found to be weakly dependent on isospin asymmetry and temperature. We discuss the possible implications emanating from this analysis, which a...
Shlomo, S; Natowitz, J B; Qin, L; Hagel, K; Wada, R; Bonasera, A
2009-01-01
We explore the abundance of light clusters in asymmetric nuclear matter at subsaturation density. With increasing density, binding energies and wave functions are modified due to medium effects. The method of Albergo, Costa, Costanzo and Rubbino (ACCR) for determining the temperature and free nucleon density of a disassembling hot nuclear source from fragment yields is modified to include, in addition to Coulomb effects and flow, also effects of medium modifications of cluster properties, which become of importance when the nuclear matter density is above 10$^{-3}$ fm$^{-3}$. We show how the analysis of cluster yields, to infer temperature and nucleon densities, is modified if the shifts in binding energies of in medium clusters are included. While, at low densities, the temperature calculated from given yields changes only modestly if medium effects are taken into account, larger discrepancies are observed when the nucleon densities are determined from measured yields.
Quark and gluon condensates in nuclear matter with Brown- Rho scaling
Institute of Scientific and Technical Information of China (English)
郭华; 杨树; 刘玉鑫
2001-01-01
Quark and gluon condensates in nuclear matter are investigated in a density-dependent relativistic mean-field theory. The in-medium quark condensate decreases rapidly as the density of nu-clear matter increases, if the Brown-Rho scaling is included. The decrease in the in-medium quark condensate with the nuclear matter density is consistent with the result predicted by the partial chiral symmetry restoration. The gluon condensate and the influence of the strange quark contents on the gluon condensate in nuclear matter are discussed.
Effect of nuclear matter incompressibility on the +Pb208O16 system
Ghodsi, O. N.; Torabi, F.
2016-06-01
To analyze the property of nuclear matter in the +Pb208O16 collision system, the internuclear potential of the fusion reaction is calculated by using the Skyrme forces associated with an extensive nuclear matter incompressibility K range in the semiclassical energy-density formalism. Comparison of the experimental fusion cross sections and those obtained by using potentials derived from different forces with various K values shows that the incompressibility of nuclear matter changes during the fusion process at different bombarding energies. The results indicate that, as the energy increases, the nuclear matter becomes more incompressible.
International Nuclear Information System (INIS)
Using a non-relativistic model we compute the response of symmetric nuclear matter and find that final state interaction effects become negligible for momentum transfers q> or approx.(0.6-0.7)m. This indicates that for moderate energy losses, nuclear matter becomes asymptotically free beyond the onset, but not deep into the relativistic regime. We then assess the importance of off-shell effects in the binary collision t-matrix and show that on-shell approximations approach the off-shell response only for q> or approx.2 GeV. Next we argue that Vopt cannot generally replace the interaction of the recoiling particle with the medium. Finally we show that for fixed q the response decreases exponentially as function of a scaling variable γ, if the imaginary part of the high-q elastic amplitude dominates. (orig.)
Reinhard, P.-G.; Nazarewicz, W.
2016-05-01
Background: 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. Purpose: In this work, by studying the correlation of charge and neutron radii, and neutron skin, with nuclear matter parameters, we assess different mechanisms that drive nuclear sizes. Method: We apply nuclear density functional theory using a family of Skyrme functionals obtained by means of optimization protocols, which do not include any radius information. By performing the Monte Carlo sampling of reasonable functionals around the optimal parametrization, we scan all correlations between nuclear matter properties and observables characterizing charge and neutron distributions of spherical closed-shell nuclei 48Ca,208Pb, and 298Fl. Results: By considering the influence of various nuclear matter properties on charge and neutron radii in a multidimensional parameter space of Skyrme functionals, we demonstrate the existence of two strong relationships: (i) between the nuclear charge radii and the saturation density of symmetric nuclear matter ρ0, and (ii) between the neutron skins and the slope of the symmetry energy L . The impact of other nuclear matter properties on nuclear radii is weak or nonexistent. For functionals optimized to experimental binding energies only, proton and neutron radii are found to be weakly correlated due to canceling trends from different nuclear matter characteristics. Conclusion: The existence of only two strong relations connecting nuclear radii with nuclear matter properties has important consequences. First, by requiring that the nuclear functional reproduces the empirical saturation point of symmetric nuclear matter practically fixes the charge (or proton) radii, and vice versa. This explains the recent results of ab initio calculations
J/psi production in proton-nucleus collisions at ALICE: cold nuclear matter really matters
CERN. Geneva
2013-01-01
Heavy quarkonia are expected to be sensitive to the properties of strongly interacting matter, at both low and high temperatures. In nucleus-nucleus collisions, a phase transition to a deconfined state of quarks and gluons (Quark-Gluon Plasma) is thought to take place once the temperature of the system exceeds a critical temperature of the order of 150-200 MeV. The deconfined state can induce a suppression of charmonium (due to color screening, dominant at SPS and RHIC energies), which can be overturned at LHC energy by the (re)combination of the large number of free c and cbar quarks, taking place when the system cools down below the critical temperature. Cold nuclear matter also has an influence on heavy quarkonia. Such effects can be studied in proton-nucleus collisions, where no deconfined state is expected to be created. At LHC energy, they mainly include nuclear shadowing, gluon saturation, break-up of the quarkonium states, and parton energy loss in the initial and final state. The study of these eff...
Thermodynamic properties of nuclear matter with three-body forces
Somà, V.; Bożek, P.
2009-08-01
We calculate thermodynamic quantities in symmetric nuclear matter within the self-consistent Green's functions method including three-body forces. The thermodynamic potential is computed directly from a diagrammatic expansion, implemented with the CD-Bonn and Nijmegen nucleon-nucleon potentials and the Urbana three-body forces. We present results for entropy and pressure up to temperatures of 20 MeV and densities of 0.32fm-3. While the pressure is sensitive to the inclusion of three-body forces, the entropy is not. The unstable spinodal region is identified and the critical temperature associated to the liquid-gas phase transition is determined. When three-body forces are added we find a strong reduction of the critical temperature, obtaining Tc≃12MeV.
Thermodynamic properties of nuclear matter with three-body forces
Soma, V
2009-01-01
We calculate thermodynamic quantities in symmetric nuclear matter within the self-consistent Green's functions method including three-body forces. The thermodynamic potential is computed directly from a diagrammatic expansion, implemented with the CD-Bonn and Nijmegen nucleon-nucleon potentials and the Urbana three-body forces. We present results for entropy and pressure up to temperatures of 20 MeV and densities of 0.32 fm^-3. While the pressure is sensitive to the inclusion of three-body forces, the entropy is not. The unstable spinodal region is identified and the critical temperature associated to the liquid-gas phase transition is determined. When three-body forces are added we find a strong reduction of the critical temperature, obtaining T_c ~ 12 MeV.
Quantum Vacuum in Hot Nuclear Matter A Nonperturbative Treatment
Mishra, A K; Greiner, W; Mishra, Amruta
2001-01-01
We derive the equation of state for hot nuclear matter using Walecka model in a nonperturbative formalism. We include here the vacuum polarisation effects arising from the nucleon and scalar mesons through a realignment of the vacuum. A ground state structure with baryon-antibaryon condensates yields the results obtained through the relativistic Hartree approximation (RHA) of summing baryonic tadpole diagrams. Generalization of such a state to include the quantum effects for the scalar meson fields through the $\\sigma$-meson condensates amounts to summing over a class of multiloop diagrams. The techniques of thermofield dynamics (TFD) method are used for the finite temperature and finite density calculations. The in-medium nucleon and sigma meson masses are also calculated in a self consistent manner. We examine the liquid-gas phase transition at low temperatures ($\\approx$ 20 MeV), as well as apply the formalism to high temperatures to examine for a possible chiral symmetry restoration phase transition.
Some problems of nuclear reactor control by an asymmetric regulating system
International Nuclear Information System (INIS)
Design criteria of an asymmetric reactor control system based on spatially divided measuring and regulating elements are analyzed. The system ensure stability of the power field, that is significantly unstable in the absence of the external feedback. The response of the regulating system to external disturbances causes deviations in the field profile, the transient times being equal to 7-8 largest time constants. In the case the total power also changes. A combined system comprising the asymmetric regulator and a total power regulator provides for field stability and remains the total power intact, but the vanations of the field shape from the initial one remain significant and the transient times are equal to 3 largest time constants. A comparative analysis has shown that a system based on the principles of local control maintains total power and field profile more precisely
Short-range correlations in quark and nuclear matter
Energy Technology Data Exchange (ETDEWEB)
Froemel, Frank
2007-06-15
In the first part of this thesis, the role of short-range correlations in quark matter is explored within the framework of the Nambu-Jona-Lasinio model. Starting from a next-to-leading order expansion in the inverse number of the quark colors, a fully self-consistent model constructed that employs the close relations between spectral functions and self-energies. In contrast to the usual quasiparticle approximations, this approach allows the investigation of the collisional broadening of the quark spectral function. Numerical calculations at various chemical potentials and zero temperature show that the short-range correlations do not only induce a finite width of the spectral function but also have some influence on the structure of the chiral phase transition. In the second part of this thesis, the temperature and density dependence of the nucleon spectral function in symmetric nuclear matter is investigated. The short-range correlations can be well described by a simple, self-consistent model on the one-particle-two-hole and two-particle-one-hole level (1p2h, 2p1h). The thermodynamically consistent description of the mean-field properties of the nucleons is ensured by incorporating a Skyrme-type potential. Calculations at temperatures and densities that can also be found in heavy-ion collisions or supernova explosions and the formation of neutron stars show that the correlations saturate at high temperatures and densities. (orig.)
Chaturvedi, O S K; Kumar, Ashwini; Singh, B K
2016-01-01
The charged particle multiplicity ($n_{ch}$) and pseudorapidity density $(dn_{ch}/d\\eta)$ are key observables to characterize the properties of matter created in heavy ion collisions. The dependence of these observables on collision energy and the collision geometry are a key tool to understand the underlying particle production mechanism. Recently a lot of focus on asymmetric nuclei as well as deformed nuclei collisions has been made as these collisions can provide a deeper understanding of the nature of quantum chromodynamics (QCD). On phenomenological perspective a unified model which describes the experimental data coming from various kind of collision experiments, is much needed to provide the physical insights about the production mechanism. In this paper, firstly we have calculated the charged hadron multiplicities for nucleon-nucleus (such as proton-lead (p-Pb) and asymmetric nuclei collisions like deutron-gold (d-Au), and copper-gold (Cu-Au) within our recently proposed wounded quark model (WQM) and ...
Nuclear matter equation of state including few-nucleon correlations $(A\\leq 4)$
Röpke, G
2014-01-01
Light clusters (mass number $A \\leq 4$) in nuclear matter at subsaturation densities are described using a quantum statistical approach. In addition to self-energy and Pauli-blocking, effects of continuum correlations are taken into account to calculate the quasiparticle properties and abundances of light elements. Medium-modified quasiparticle properties are important ingredients to derive a nuclear matter equation of state applicable in the entire region of warm dense matter below saturatio...
Sahoo, Babita; Chakraborty, Suparna; Sahoo, Sukadev
2016-01-01
Momentum and density dependence of single-nucleon potential u τ (k, ρ, β) is analyzed using a density dependent finite range effective interaction of the Yukawa form. Depending on the choice of the strength parameters of exchange interaction, two different trends of the momentum dependence of nuclear symmetry potential are noticed which lead to two opposite types of neutron and proton effective mass splitting. The 2nd-order and 4th-order symmetry energy of isospin asymmetric nuclear matter are expressed analytically in terms of the single-nucleon potential. Two distinct behavior of the density dependence of 2nd-order and 4th-order symmetry energy are observed depending on neutron and proton effective mass splitting. It is also found that the 4th-order symmetry energy has a significant contribution towards the proton fraction of β-stable npeμ matter at high densities.
Diffusion of dark matter in a hot and dense nuclear environment
Cermeño, Marina; Pérez-García, M. Ángeles; Silk, Joseph
2016-07-01
We calculate the mean free path in a hot and dense nuclear environment for a fermionic dark matter particle candidate in the ˜GeV mass range interacting with nucleons via scalar and vector effective couplings. We focus on the effects of density and temperature in the nuclear medium in order to evaluate the importance of the final state blocking in the scattering process. We discuss qualitatively possible implications for opacities in stellar nuclear scenarios, where dark matter may be gravitationally accreted.
Relativistic description of BCS-BEC crossover in nuclear matter
Sun, Bao Yuan; Toki, Hiroshi; Meng, Jie
2010-01-01
We study theoretically the di-neutron spatial correlations and the crossover from superfluidity of neutron Cooper pairs in the S10 pairing channel to Bose-Einstein condensation (BEC) of di-neutron pairs for both symmetric and neutron matter in the microscopic relativistic pairing theory. We take the bare nucleon-nucleon interaction Bonn-B in the particle-particle channel and the effective interaction PK1 of the relativistic mean-field approach in the particle-hole channel. It is found that the spatial structure of neutron Cooper pair wave function evolves continuously from BCS-type to BEC-type as density decreases. We see a strong concentration of the probability density revealed for the neutron pairs in the fairly small relative distance around 1.5 fm and the neutron Fermi momentum kFn ∈ [ 0.6 , 1.0 ] fm-1. However, from the effective chemical potential and the quasiparticle excitation spectrum, there is no evidence for the appearance of a true BEC state of neutron pairs at any density. The most BEC-like state may appear at kFn ∼ 0.2 fm-1 by examining the density correlation function. From the coherence length and the probability distribution of neutron Cooper pairs as well as the ratio between the neutron pairing gap and the kinetic energy at the Fermi surface, some features of the BCS-BEC crossover are seen in the density regions, 0.05 fm-1
Sammarruca, Francesca
2016-01-01
We present predictions of the binding energy per nucleon and the neutron skin thickness in highly neutron-rich isotopes of Oxygen, Magnesium, and Aluminum. The calculations are carried out at and below the neutron drip line. The nuclear properties are obtained via an energy functional whose input is the equation of state of isospin-asymmetric in?finite matter. The latter is based on a microscopic derivation applying chiral few-nucleon forces. We highlight the impact of the equation of state at diff?erent orders of chiral effective fi?eld theory and discuss the role of three-neutron forces.
Neutron-Proton Mass Difference in Nuclear Matter and in Finite Nuclei and the Nolen-Schiffer Anomaly
Directory of Open Access Journals (Sweden)
Yakhshiev U.T.
2010-04-01
Full Text Available The neutron-proton mass diﬀerence in (isospin asymmetric nuclear matter and ﬁnite nuclei is studied in the framework of a medium-modiﬁed Skyrme model. The proposed eﬀective Lagrangian incorporates both the medium inﬂuence of the surrounding nuclear environment on the single nucleon properties and an explicit isospin-breaking eﬀect in the mesonic sector. Energy-dependent charged and neutral pion optical potentials in the s- and p-wave channels are included as well. The present approach predicts that the neutron-proton mass diﬀerence is mainly dictated by its strong part and that it markedly decreases in neutron matter. Furthermore, the possible interplay between the eﬀective nucleon mass in ﬁnite nuclei and the Nolen-Schiﬀer anomaly is discussed. In particular, we ﬁnd that a correct description of the properties of mirror nuclei leads to a stringent restriction of possible modiﬁcations of the nucleon’s eﬀective mass in nuclei.
A new explanation to the cold nuclear matter effects in heavy ion collisions
Liu, Zhi-Feng
2014-01-01
The J/Psi cross section ratios of p-A/p-p under different collision energy is calculated with cold nuclear matter effects redefined in this paper. The advantage of these new definitions is that all cold nuclear matter effects have clear physical origins.The radios are compared with the corresponding experiment data and that calculated with classic nuclear effects. The ratios calculated with new definitions can reproduce almost all existing J/Psi measurements in p-A collisions more accuratly than that calculated with classic nuclear effects. Hence, this paper presents a new approach to explain cold nuclear effects in the hardproduction of quarkonium.
Multiplicity and cold-nuclear matter effects from Glauber-Gribov theory at LHC
Arsene, I. C.; Bravina, L.; Kaidalov, A.B.; Tywoniuk, K.; Zabrodin, E.
2007-01-01
We present predictions for nuclear modification factor in proton-lead collisions at LHC energy 5.5 TeV from Glauber-Gribov theory of nuclear shadowing. We have also made predictions for baseline cold-matter nuclear effects in lead-lead collisions at the same energy.
Hadronization time of heavy quarks in nuclear matter
Song, Taesoo; Berrehrah, Hamza
2016-09-01
We study the hadronization time of heavy quark in nuclear matter by using the coalescence model and the spatial diffusion constant of a heavy quark from lattice quantum chromodynamic calculations, assuming that the main interaction of a heavy quark at the critical temperature is hadronization. It is found that the hadronization time of a heavy quark is about 3 fm /c for 2 π TcDs=6 , if a heavy quark is combined with the nearest light antiquark in coordinate space without any correlation between the momentum of a heavy quark and that of a light antiquark which forms a heavy meson. However, the hadronization time reduces to 0.6 - 1.2 fm /c for charm and 0.4 - 0.9 fm /c for bottom, depending on the heavy meson radius, in the presence of momentum correlation. Considering the interspace between quarks and antiquarks at the critical temperature, it seems that the hadronization of a heavy quark does not happen instantaneously but gradually for a considerable time, if started from the thermal distribution of quarks and antiquarks.
Correlations between critical parameters and bulk properties of nuclear matter
Lourenço, O; Dutra, M; Delfino, A
2016-01-01
The present work starts by providing a clear identification of correlations between critical parameters ($T_c$, $P_c$, $\\rho_c$) and bulk quantities at zero temperature of relativistic mean-field models (RMF) presenting third and fourth order self-interactions in the scalar field $\\sigma$. Motivated by the nonrelativistic version of this RMF model, we show that effective nucleon mass ($M^*$) and incompressibility ($K_o$), at the saturation density, are correlated with $T_c$, $P_c$, and $\\rho_c$, as well as, binding energy and saturation density itself. We verify agreement of results with previous theoretical ones regarding different hadronic models. Concerning recent experimental data of the symmetric nuclear matter critical parameters, our study allows a prediction of $T_c$, $P_c$ and $\\rho_c$ compatible with such values, by combining them, through the correlations found, with previous constraints related to $M^*$ and $K_o$. An improved RMF parametrization, that better agrees with experimental values for $T_...
In-medium effective chiral lagrangians and the pion mass in nuclear matter
Wirzba, A; Wirzba, Andreas; Thorsson, Vesteinn
1995-01-01
We argue that the effective pion mass in nuclear matter obtained from chiral effective lagrangians is unique and does not depend on off-mass-shell extensions of the pion fields as e.g. the PCAC choice. The effective pion mass in isospin symmetric nuclear matter is predicted to increase slightly with increasing nuclear density, whereas the effective time-like pion decay constant and the magnitude of the density-dependent quark condensate decrease appreciably. The in-medium Gell-Mann-Oakes-Renner relation as well as other in-medium identities are studied in addition. Finally, several constraints on effective lagrangians for the description of the pion propagation in isospin symmetric, isotropic and homogenous nuclear matter are discussed. (Talk presented at the workshop ``Hirschegg '95: Hadrons in Nuclear Matter'', Hirschegg, Kleinwalsertal, Austria, January 16-21, 1995)
Experimental aspects of quarkonia production and suppression in cold and hot nuclear matter
Frawley, A D
2015-01-01
When heavy Quarkonia are formed in collisions between between nuclei, their production cross section is modified relative to that in p+p collisions. The physical effects that cause this modification fall into two categories. Hot matter effects are due to the large energy density generated in the nuclear collision, which disrupts the formation of the quarkonium state. Cold nuclear matter effects are due to the fact that the quarkonium state is created in a nuclear target. I will review experimental aspects of quarkonia production due to both hot and cold matter effects.
Microscopic calculations and energy expansions for neutron-rich matter
Energy Technology Data Exchange (ETDEWEB)
Drischler, Christian; Soma, Vittorio [Institut fuer Kernphysik, Technische Universitaet Darmstadt (Germany); ExtreMe Matter Institute EMMI, GSI Helmholtzzentrum fuer Schwerionenforschung GmbH (Germany); Schwenk, Achim [ExtreMe Matter Institute EMMI, GSI Helmholtzzentrum fuer Schwerionenforschung GmbH (Germany); Institut fuer Kernphysik, Technische Universitaet Darmstadt (Germany)
2014-07-01
We investigate the properties of asymmetric nuclear matter with two- and three-nucleon interactions based on chiral effective field theory. Focusing on neutron-rich matter, we calculate the energy for different proton fractions and include estimates of the theoretical uncertainty. We use our ab-initio results to test the quadratic expansion around symmetric matter with the symmetry energy term, and confirm its validity for highly asymmetric systems. Our calculated energy densities are in remarkable agreement with an empirical parameterization, developed to interpolate between pure neutron and symmetric nuclear matter. These findings are very useful for astrophysical applications and for developing new equations of state.
Jung, Ju-Hyun; Kim, Hyun-Chul
2015-01-01
We investigate the medium modification of the generalized vector form factors of the nucleon, which include the electromagnetic and energy-momentum tensor form factors, based on an in-medium modified $\\pi$-$\\rho$-$\\omega$ soliton model. We find that the vector form factors of the nucleon in nuclear matter fall off faster than those in free space, which implies that the charge radii of the nucleon become larger in nuclear medium than in free space. We also compute the corresponding transverse charge densities of the nucleon in nuclear matter, which clearly reveal the increasing of the nucleon size in nuclear medium.
Critical analysis of quark-meson coupling models for nuclear matter and finite nuclei
Müller, H; Mueller, Horst; Jennings, Byron K.
1998-01-01
Three versions of the quark-meson coupling (QMC) model are applied to describe properties of nuclear matter and finite nuclei. The models differ in the treatment of the bag constant and in terms of nonlinear scalar self-interactions. As a consequence opposite predictions for the medium modifications of the internal nucleon structure arise. After calibrating the model parameters at equilibrium nuclear matter density, binding energies, charge radii, single-particle spectra and density distributions of spherical nuclei are analyzed and compared with QHD calculations. For the models which predict a decreasing size of the nucleon in the nuclear environment, unrealistic features of the nuclear shapes arise.
Current status of the nuclear matter incompressibility coefficient
International Nuclear Information System (INIS)
We review the current status of the incompressibility coefficient of symmetric nuclear matter, Knm, as deduced from experimental data on excitation cross section, σ(E), of the isoscalar giant monopole resonance (ISGMR) and the isoscalar giant dipole resonance (ISGDR), by inelastic α-particle scattering, using the nonrelativistic and relativistic mean-field based random phase approximation (RPA). We will discuss the following problems: (1) Self-consistent (non-relativistic) Hartree-Fock (HF)-based RPA calculations and the need to carry out detailed and accurate calculations of the strength function distributions, S(E), and the transition densities, pt, of the isoscalar giant resonance within the HF-RPA theory. We will present results of our investigation concerning, (i) the consequences of violation of self-consistency in common applications of HF-based RPA on S(E) and p, of isoscalar giant resonances, and (ii) the effects of the spurious state mixing (SSM) on properties of the ISGDR. (2) The relation between the strength function S(E) and the excitation cross section a(E) of the isoscalar giant resonances (the ISGMR and the ISGDR, in particular) obtained by alpha-scattering. Here we present results of accurate microscopic calculations for S(E) and for σ(E), obtained within the folding-model distorted-wave-Born approximation with transition densities pt(r ) obtained from HF-RPA calculations. We provide an explanation for the discrepancy between theory and experiment concerning S(E) of the ISGDR. (3) The apparent discrepancy of about 20 % in the value of Knm as predicted by the relativistic and the non-relativistic models. Our investigation suggests that this discrepancy is mainly due to the different values of the symmetry energy coefficient employed in the relativistic and the non-relativistic models
Influence of spin polarizability on liquid gas phase transition in the nuclear matter
Rezaei, Z; Bordbar, G H
2015-01-01
In this paper, we investigate the liquid gas phase transition for the spin polarized nuclear matter. Applying the lowest order constrained variational (LOCV) method, and using two microscopic potentials, $AV_{18}$ and $UV_{14}$+TNI, we calculate the free energy, equation of state, order parameter, entropy, heat capacity and compressibility to derive the critical properties of spin polarized nuclear matter. Our results indicate that for the spin polarized nuclear matter, the second order phase transition takes place at lower temperatures with respect to the unpolarized one. It is also shown that the critical temperature of our spin polarized nuclear matter with a specific value of spin polarization parameter is in good agreement with the experimental result.
Nuclear matter equation of state including few-nucleon correlations $(A\\leq 4)$
Röpke, G
2014-01-01
Light clusters (mass number $A \\leq 4$) in nuclear matter at subsaturation densities are described using a quantum statistical approach. In addition to self-energy and Pauli-blocking, effects of continuum correlations are taken into account to calculate the quasiparticle properties and abundances of light elements. Medium-modified quasiparticle properties are important ingredients to derive a nuclear matter equation of state applicable in the entire region of warm dense matter below saturation density. Moreover, the contribution of continuum states to the equation of state is considered. The effect of correlations within the nuclear medium on the quasiparticle energies is estimated. The properties of light clusters and continuum correlations in dense matter are of interest for nuclear structure calculations, heavy ion collisions, and for astrophysical applications such as the formation of neutron stars in core-collapse supernovae.
Volume integral of particle-particle collision probability in nuclear matter
International Nuclear Information System (INIS)
Average volume integrals per nucleon of particle-particle collision probability in nuclear matter are evaluated using the preequilibrium exciton model. The results obtained are in quite reasonable accord with the volume integrals of optical model absorptive potentials
Study of Charmonium Production in Asymmetric Nuclear Collisions by the PHENIX Experiment at RHIC
,
2015-01-01
The measurement of quarkonia production in relativistic heavy ion collisions provides a powerful tool for studying the properties of the hot and dense matter created in these collisions. To be really useful, however, such measurements must cover a wide range of quarkonia states and colliding species. The PHENIX experiment at RHIC has successfully measured J/psi, psi-prime, chi_c and Upsilon production in different colliding systems at various energies. In this talk I will present recent results from the PHENIX collaboration on charmonium production in d+Au, Cu+Au and U+U collisions at 200 GeV/c.
Do Skyrme forces that fit nuclear matter work well in finite nuclei?
Stevenson, P D; Stone, J R; Dutra, M
2012-01-01
A shortlist of Skyrme force parameterizations, recently found to have passed a series of constraints relating to nuclear matter properties is analyzed for their ability to reproduce data in finite nuclei. We analyse binding energies, isotope shifts and fission barriers. We find that the subset of forces have no common ability to reproduce (or otherwise) properties of finite nuclei, despite passing the extensive range of nuclear matter constraints.
Chiral Effective Lagrangian Description of Nuclear Matter with in-Medium Pion Effect
Institute of Scientific and Technical Information of China (English)
张小兵; 宁平治
2003-01-01
By including the in-medium pion effect, we study the description of nuclear matter based on the non-linear chiral Lagrangian at the leading order. An in-medium effective Lagrangian is constructed without the necessity of introducing the phenomenological scalar-isoscalar field. At the mean-field level, the in-medium Lagrangian description of nuclear matter is shown to be compatible with that obtained from the Brown-Rho scaled model.
Saturation properties of nuclear matter in the presence of strong magnetic field
Energy Technology Data Exchange (ETDEWEB)
Rezaei, Z. [Shiraz University, Department of Physics and Biruni Observatory, Shiraz (Iran, Islamic Republic of); Bordbar, G.H. [Shiraz University, Department of Physics and Biruni Observatory, Shiraz (Iran, Islamic Republic of); Center for Excellence in Astronomy and Astrophysics (CEAA-RIAAM)-Maragha, P.O. Box 55134-441, Maragha (Iran, Islamic Republic of)
2016-05-15
Different saturation properties of cold symmetric nuclear matter in strong magnetic field have been considered. We have seen that for magnetic fields about B>3 x 10{sup 17} G, for both cases with and without nucleon anomalous magnetic moments, the saturation density and saturation energy grow by increasing the magnetic field. It is indicated that the magnetic susceptibility of symmetric nuclear matter becomes negative showing the diamagnetic response especially at B<3 x 10{sup 17} G. We have found that for the nuclear matter, the magnitude of orbital magnetization reaches higher values comparing to the spin magnetization. Our results for the incompressibility show that at high enough magnetic fields, i.e. B>3 x 10{sup 17} G, the softening of the equation of state caused by Landau quantization is overwhelmed by stiffening due to the magnetization of nuclear matter. We have shown that the effects of strong magnetic field on nuclear matter may affect the constraints on the equation of state of symmetric nuclear matter obtained by applying the experimental observables. (orig.)
Functional renormalization group approach to neutron matter
Directory of Open Access Journals (Sweden)
Matthias Drews
2014-11-01
Full Text Available The chiral nucleon-meson model, previously applied to systems with equal number of neutrons and protons, is extended to asymmetric nuclear matter. Fluctuations are included in the framework of the functional renormalization group. The equation of state for pure neutron matter is studied and compared to recent advanced many-body calculations. The chiral condensate in neutron matter is computed as a function of baryon density. It is found that, once fluctuations are incorporated, the chiral restoration transition for pure neutron matter is shifted to high densities, much beyond three times the density of normal nuclear matter.
The Heart of Matter: A Nuclear Chemistry Module. Teacher's Guide.
Viola, Vic; Hearle, Robert
This teacher's guide is designed to provide science teachers with the necessary guidance and suggestions for teaching nuclear chemistry. In this book, the fundamental concepts of nuclear science and the applications of nuclear energy are discussed. The material in this book can be integrated with the other modules in a sequence that helps students…
Gu, Peili; Morgan, Daniel H; Sattar, Minawar; Xu, Xueping; Wagner, Ryan; Raviscioni, Michele; Lichtarge, Olivier; Cooney, Austin J
2005-09-01
Germ cell nuclear factor (GCNF) is an orphan nuclear receptor that plays important roles in development and reproduction, by repressing the expression of essential genes such as Oct4, GDF9, and BMP15, through binding to DR0 elements. Surprisingly, whereas recombinant GCNF binds to DR0 sequences as a homodimer, endogenous GCNF does not exist as a homodimer but rather as part of a large complex termed the transiently retinoid-induced factor (TRIF). Here, we use evolutionary trace (ET) analysis to design mutations and peptides that probe the molecular basis for the formation of this unusual complex. We find that GCNF homodimerization and TRIF complex formation are DNA-dependent, and ET suggests that dimerization involves key functional sites on both helix 3 and helix 11, which are located on opposing surfaces of the ligand binding domain. Targeted mutations in either helix of GCNF disrupt the formation of both the homodimer and the endogenous TRIF complex. Moreover, peptide mimetics of both of these ET-determined sites inhibit dimerization and TRIF complex formation. This suggests that a novel helix 3-helix 11 heterotypic interaction mediates GCNF interaction and would facilitate oligomerization. Indeed, it was determined that the endogenous TRIF complex is composed of a GCNF oligomer. These findings shed light on an evolutionarily selected mechanism that reveals the unusual DNA-binding, dimerization, and oligomerization properties of GCNF.
Some Recent Progress on Quark Pairings in Dense Quark and Nuclear Matter
Institute of Scientific and Technical Information of China (English)
庞锦毅; 王金成; 王群
2012-01-01
In this review article we give a brief overview on some recent progress in quark pairings in dense quark~nuclear matter mostly developed in the past five years. We focus on following aspects in particular： the BCS-BEC crossover in the CSC phase, the baryon formation and dissociation in dense quark/nuclear matter, the Ginzburg-Landau theory for three-flavor dense matter with UA （1） anomaly, and the collective and Nambu-Goldstone modes for the spin-one CSC.
Nuclear matter with three-body forces from self-consistent spectral calculations
Soma, Vittorio; Bozek, Piotr
2007-01-01
We calculate the equation of state of nuclear matter in the self-consistent T-matrix scheme including three-body nuclear interactions. We study the effect of the three-body force on the self-energies and spectral functions of nucleons in medium.
Can Tonne-Scale Direct Detection Experiments Discover Nuclear Dark Matter?
Butcher, A; Monroe, J; West, S M
2016-01-01
Models of nuclear dark matter propose that the dark sector contains large composite states consisting of dark nucleons in analogy to Standard Model nuclei. We examine the direct detection phenomenology of a particular class of nuclear dark matter model at the current generation of tonne-scale liquid noble experiments, in particular DEAP-3600 and XENON1T. In our chosen nuclear dark matter scenario distinctive features arise in the recoil energy spectra due to the non-point-like nature of the composite dark matter state. We calculate the number of events required to distinguish these spectra from those of a standard point-like WIMP state with a decaying exponential recoil spectrum. In the most favourable regions of nuclear dark matter parameter space, we find that a few tens of events are needed to distinguish nuclear dark matter from WIMPs at the $3\\,\\sigma$ level in a single experiment. Given the total exposure time of DEAP-3600 and XENON1T we find that at best a $2\\,\\sigma$ distinction is possible by these e...
Study of the nuclear matter distribution of exotic Be and B nuclei
Energy Technology Data Exchange (ETDEWEB)
Ilieva, S.; Aksouh, F.; Behr, K.H.; Bleile, A.; Bruenle, A.; Egelhof, P.; Geissel, H.; Ickert, G.; Inglessi, A.; Kanungo, R.; Kiselev, O.; Le, X.C.; Litvinov, Y.; Niebur, W.; Nociforo, C.; Weick, H. [Gesellschaft fuer Schwerionenforschung (GSI), Darmstadt (Germany); Alkhazov, G.D.; Dobrovolsky, A.V.; Khanzadeev, A.V.; Korolev, G.A.; Seliverstov, D.M.; Sergeev, L.O.; Vorobyov, A.A.; Yatsoura, V.I.; Zhdanov, A.A. [Petersburg Nuclear Physics Institute (PNPI), Gatchina (Russian Federation); Chulkov, L.; Volkov, V.A. [Kurchatov Institute, Moscow (Russian Federation)
2008-07-01
Exotic nuclei close to the drip-lines have revealed an interesting type of nuclear structure with a widely extended matter distribution of loosely bound valence nucleons(halo) surrounding a compact core. In the present work the differential cross sections for small-angle proton elastic scattering on the {sup 12,14}Be and {sup 8}B isotopes were analyzed. The experiment was performed at energies near 700 MeV/u in inverse kinematics using the active target detector IKAR at GSI, Darmstadt. The measured cross sections were analyzed with the aid of the Glauber multiple-scattering theory. Nuclear matter radii and radial matter distributions have been deduced. The nuclear matter distribution for {sup 14}Be exhibits a pronounced neutron halo structure while for {sup 8}B a proton halo is observed. The obtained data allow for a test of various theoretical model calculations of the structure of the studied isotopes.
Study of the nuclear matter distribution in neutron-rich Li isotopes
Energy Technology Data Exchange (ETDEWEB)
Dobrovolsky, A.V. [Petersburg Nuclear Physics Institute (PNPI), 188300 Gatchina (Russian Federation)]. E-mail: dobrov@pnpi.spb.ru; Alkhazov, G.D. [Petersburg Nuclear Physics Institute (PNPI), 188300 Gatchina (Russian Federation); Andronenko, M.N. [Petersburg Nuclear Physics Institute (PNPI), 188300 Gatchina (Russian Federation); Bauchet, A. [Gesellschaft fuer Schwerionenforschung (GSI), 64291 Darmstadt (Germany); Egelhof, P. [Gesellschaft fuer Schwerionenforschung (GSI), 64291 Darmstadt (Germany); Fritz, S. [Gesellschaft fuer Schwerionenforschung (GSI), 64291 Darmstadt (Germany); Geissel, H. [Gesellschaft fuer Schwerionenforschung (GSI), 64291 Darmstadt (Germany); Gross, C. [Gesellschaft fuer Schwerionenforschung (GSI), 64291 Darmstadt (Germany); Khanzadeev, A.V. [Petersburg Nuclear Physics Institute (PNPI), 188300 Gatchina (Russian Federation); Korolev, G.A. [Petersburg Nuclear Physics Institute (PNPI), 188300 Gatchina (Russian Federation); Kraus, G. [Gesellschaft fuer Schwerionenforschung (GSI), 64291 Darmstadt (Germany); Lobodenko, A.A. [Petersburg Nuclear Physics Institute (PNPI), 188300 Gatchina (Russian Federation); Muenzenberg, G. [Gesellschaft fuer Schwerionenforschung (GSI), 64291 Darmstadt (Germany); Mutterer, M. [Institut fuer Kernphysik (IKP), TU-Darmstadt, 64289 Darmstadt (Germany); Neumaier, S.R. [Gesellschaft fuer Schwerionenforschung (GSI), 64291 Darmstadt (Germany); Institut fuer Kernphysik (IKP), TU-Darmstadt, 64289 Darmstadt (Germany); Schaefer, T. [Gesellschaft fuer Schwerionenforschung (GSI), 64291 Darmstadt (Germany); Scheidenberger, C. [Gesellschaft fuer Schwerionenforschung (GSI), 64291 Darmstadt (Germany); Seliverstov, D.M. [Petersburg Nuclear Physics Institute (PNPI), 188300 Gatchina (Russian Federation); Timofeev, N.A. [Petersburg Nuclear Physics Institute (PNPI), 188300 Gatchina (Russian Federation); Vorobyov, A.A.; Yatsoura, V.I. [Petersburg Nuclear Physics Institute (PNPI), 188300 Gatchina (Russian Federation)
2006-02-20
The differential cross sections for small-angle proton elastic scattering on the {sup 6,8,9,11}Li nuclei at energies near 700 MeV/nucleon were measured in inverse kinematics using secondary nuclear beams at GSI Darmstadt. The hydrogen-filled ionization chamber IKAR was employed as target and recoil proton detector. For determining the nuclear matter radii and radial matter distributions, the measured cross sections have been analysed with the aid of the Glauber multiple-scattering theory. The nuclear matter distribution deduced for {sup 11}Li exhibits a very pronounced halo structure, the matter radius of {sup 11}Li being significantly larger than those of the {sup 6,8,9}Li isotopes. The data on {sup 8,9}Li are consistent with the existence of sizable neutron skins in these nuclei. The obtained data allow for a test of various theoretical model calculations of the structure of the studied neutron-rich nuclei.
Gupta, V K; Singh, S; Anand, J D; Gupta, Asha
2002-01-01
We have studied phase transition from hadron matter to quark matter in the presence of high magnetic fields incorporating the trapped electron neutrinos at finite temperatures. We have used the density dependent quark mass (DDQM) model for the quark phase while the hadron phase is treated in the frame-work of relativistic mean field theory. It is seen that the nuclear energy at phase transition decreases with both magnetic field and temperature. A brief discussion of the effect of magnetic field in supernova explosions and proto-neutron star evolution is given.
A beyond-mean-field example with zero-range effective interactions in infinite nuclear matter
Moghrabi, K; Roca-Maza, X; Coló, G; Van Giai, N; 10.1051/epjconf/20123806002
2013-01-01
Zero-range effective interactions are commonly used in nuclear physics to describe a many-body system in the mean-field framework. If they are employed in beyond- mean-field models, an artificial ultraviolet divergence is generated by the zero-range of the interaction. We analyze this problem in symmetric nuclear matter with the t0-t3 Skyrme model. In this case, the second-order energy correction diverges linearly with the momentum cutoff. After that, we extend the work to the case of nuclear matter with the full Skyrme interaction. A strong divergence related to the velocity-dependent terms of the interaction is obtained. Moreover, a global fit can be simultaneously performed for both symmetric and nuclear matter with different neutron-to-proton ratios. These results pave the way for applications to finite nuclei in the framework of beyond mean-field theories.
In-medium effective chiral lagrangians and the pion mass in nuclear matter
International Nuclear Information System (INIS)
We argue that the effective pion mass in nuclear matter obtained from chiral effective lagrangians is unique and does not depend on off-mass-shell extensions of the pion fields as e.g. the PCAC choice. The effective pion mass in isospin symmetric nuclear matter is predicted to increase slightly with increasing nuclear density, whereas the effective time-like pion decay constant and the magnitude of the density-dependent quark condensate decrease appreciably. The in-medium Gell-Mann-Oakes-Renner relation as well as other in-medium identities are studied in addition. Finally, several constraints on effective lagrangians for the description of the pion propagation in isospin symmetric, isotropic and homogeneous nuclear matter are discussed. (orig.)
On the Manifestation of Chiral Symmetry in Nuclei and Dense Nuclear Matter
Brown, G E; Rho, Mannque
2002-01-01
This article reviews our view on how chiral symmetry, its pattern of breaking and restoration under extreme conditions manifest themselves in the nucleon, nuclei, nuclear matter and dense hadronic matter. Topics treated are nucleon structure in terms of chiral symmetry, "first-principle" (QCD) calculations of the properties of finite nuclei effectuated by embedding the ``standard nuclear physics approach" into the framework of effective field theories of nuclei with predictions for certain astrophysical processes, a reinterpretation of the Brown-Rho (BR) scaling that implements chiral symmetry property of baryon-rich medium \\`a la "vector manifestation" of hidden local symmetry, evidences for BR scaling in nuclear processes at normal nuclear matter density and at higher density, the notion of "broadband equilibration" in heavy-ion processes, and the role of strangeness in the formation of compact stars and their collapse into black-holes. We revisit the "Cheshire-Cat phenomenon" recently revived in the form o...
Effective interaction: From nuclear reactions to neutron stars
Indian Academy of Sciences (India)
D N Basu
2014-05-01
An equation of state (EoS) for symmetric nuclear matter is constructed using the density-dependent M3Y effective interaction and extended for isospin asymmetric nuclear matter. Theoretically obtained values of symmetric nuclear matter incompressibility, isobaric incompressibility, symmetry energy and its slope agree well with experimentally extracted values. Folded microscopic potentials using this effective interaction, whose density dependence is determined from nuclear matter calculations, provide excellent descriptions for proton, alpha and cluster radioactivities, elastic and inelastic scattering. The nuclear deformation parameters extracted from inelastic scattering of protons agree well with other available results. The high density behaviour of symmetric and asymmetric nuclear matter satisfies the constraints from the observed flow data of heavy-ion collisions. The neutron star properties studied using -equilibrated neutron star matter obtained from this effective interaction reconcile with the recent observations of the massive compact stars.
Energy Technology Data Exchange (ETDEWEB)
Bock, D.; Kahlau, R.; Pötzschner, B.; Körber, T.; Wagner, E.; Rössler, E. A., E-mail: ernst.roessler@uni-bayreuth.de [Experimentalphysik II, Universität Bayreuth, 95440 Bayreuth (Germany)
2014-03-07
Various {sup 2}H and {sup 31}P nuclear magnetic resonance (NMR) spectroscopy techniques are applied to probe the component dynamics of the binary glass former tripropyl phosphate (TPP)/polystyrene-d{sub 3} (PS) over the full concentration range. The results are quantitatively compared to those of a dielectric spectroscopy (DS) study on the same system previously published [R. Kahlau, D. Bock, B. Schmidtke, and E. A. Rössler, J. Chem. Phys. 140, 044509 (2014)]. While the PS dynamics does not significantly change in the mixtures compared to that of neat PS, two fractions of TPP molecules are identified, one joining the glass transition of PS in the mixture (α{sub 1}-process), the second reorienting isotropically (α{sub 2}-process) even in the rigid matrix of PS, although at low concentration resembling a secondary process regarding its manifestation in the DS spectra. Pronounced dynamical heterogeneities are found for the TPP α{sub 2}-process, showing up in extremely stretched, quasi-logarithmic stimulated echo decays. While the time window of NMR is insufficient for recording the full correlation functions, DS results, covering a larger dynamical range, provide a satisfactory interpolation of the NMR data. Two-dimensional {sup 31}P NMR spectra prove exchange within the broadly distributed α{sub 2}-process. As demonstrated by {sup 2}H NMR, the PS matrix reflects the faster α{sub 2}-process of TPP by performing a spatially highly hindered motion on the same timescale.
2011-12-28
... COMMISSION In the Matter of ZIONSOLUTIONS, LLC; Zion Nuclear Power Station; Independent Spent Fuel Storage..., Licensing and Inspection Directorate, Division of Spent Fuel Storage and Transportation, Office of Nuclear... providing notice, in the matter of Zion Nuclear ] Power Station Independent Spent Fuel Storage...
Energy Technology Data Exchange (ETDEWEB)
Kahlau, R.; Bock, D.; Schmidtke, B.; Rössler, E. A., E-mail: ernst.roessler@uni-bayreuth.de [Experimentalphysik II, Universität Bayreuth, 95440 Bayreuth (Germany)
2014-01-28
Dielectric spectroscopy as well as {sup 2}H and {sup 31}P nuclear magnetic resonance spectroscopy (NMR) are applied to probe the component dynamics of the binary glass former tripropyl phosphate (TPP)/polystyrene (PS/PS-d{sub 3}) in the full concentration (c{sub TPP}) range. In addition, depolarized light scattering and differential scanning calorimetry experiments are performed. Two glass transition temperatures are found: T{sub g1}(c{sub TPP}) reflects PS dynamics and shows a monotonic plasticizer effect, while the lower T{sub g2}(c{sub TPP}) exhibits a maximum and is attributed to (faster) TPP dynamics, occurring in a slowly moving or immobilized PS matrix. Dielectric spectroscopy probing solely TPP identifies two different time scales, which are attributed to two sub-ensembles. One of them, again, shows fast TPP dynamics (α{sub 2}-process), the other (α{sub 1}-process) displays time constants identical with those of the slow PS matrix. Upon heating the α{sub 1}-fraction of TPP decreases until above some temperature T{sub c} only a single α{sub 2}-population exists. Inversely, below T{sub c} a fraction of the TPP molecules is trapped by the PS matrix. At low c{sub TPP} the α{sub 2}-relaxation does not follow frequency-temperature superposition (FTS), instead it is governed by a temperature independent distribution of activation energies leading to correlation times which follow Arrhenius laws, i.e., the α{sub 2}-relaxation resembles a secondary process. Yet, {sup 31}P NMR demonstrates that it involves isotropic reorientations of TPP molecules within a slowly moving or rigid matrix of PS. At high c{sub TPP} the super-Arrhenius temperature dependence of τ{sub 2}(T), as well as FTS are recovered, known as typical of the glass transition in neat systems.
Energy Technology Data Exchange (ETDEWEB)
Kang, Zhaofeng [Korea Institute for Advanced Study, School of Physics, Seoul (Korea, Republic of); Institute of Theoretical Physics, Chinese Academy of Sciences, Key Laboratory of Frontiers in Theoretical Physics, Beijing (China); Li, Jinmian [Institute of Theoretical Physics, Chinese Academy of Sciences, Key Laboratory of Frontiers in Theoretical Physics, Beijing (China); University of Adelaide, ARC Centre of Excellence for Particle Physics at the Terascale and CSSM, Department of Physics, Adelaide, SA (Australia); Li, Tianjun [Institute of Theoretical Physics, Chinese Academy of Sciences, Key Laboratory of Frontiers in Theoretical Physics, Beijing (China); University of Electronic Science and Technology of China, School of Physical Electronics, Chengdu (China); Liu, Tao [University of Alberta, Department of Physics, Edmonton, Alberta (Canada); Yang, Jin Min [Institute of Theoretical Physics, Chinese Academy of Sciences, Key Laboratory of Frontiers in Theoretical Physics, Beijing (China)
2016-05-15
The maximal U(1){sub L} supersymmetric inverse seesaw mechanism (MLSIS) provides a natural way to relate asymmetric darkmatter (ADM)with neutrino physics. In this paper we point out that MLSIS is a natural outcome if one dynamically realizes the inverse seesaw mechanism in the next-to minimal supersymmetric standard model (NMSSM) via the dimension-five operator (N){sup 2}S{sup 2}/M{sub *}, with S the NMSSM singlet developing TeV scale VEV; it slightly violates lepton number due to the suppression by the fundamental scale M{sub *}, thus preserving U(1){sub L} maximally. The resulting sneutrino is a distinguishable ADM candidate, oscillating and favored to have weak scale mass. A fairly large annihilating cross section of such a heavy ADM is available due to the presence of singlet. (orig.)
The future of the nuclear industry: a matter of communication
International Nuclear Information System (INIS)
Since the very first successes achieved by the early scientists the infant nuclear industry was plagued by an atmosphere of uncertainty, conflict, anxiety and expectations. After the initial euphoria the Chernobyl accident shocked public opinion and perspectives changed. Nuclear energy is experience by the public in three dimensions. Firstly there are the technical realities of the reactor and its fantastically reduced source of power. Secondly, there is a psychological and political meaning, including the association of modern technology with authority, government, and control. The third dimension is the product of old myths about 'divine secrets', mad scientists dreadful pollution and cosmic apocalypse. To a large extent the nuclear industry is at fault for these emotional connotations. An early lapse in the communication process can be blamed for many of the misconceptions. The nuclear industry lost an opportunity by sticking to 'vagueness'. Recent trends show that a pattern of conditional acceptance is present in public opinion with regard to the nuclear industry. Possible solutions, including better communication, aggressive marketing, and the training of scientists to become communicators, are discussed. A study was done of community attitudes around Koeberg, and it is concluded that the public must be convinced of the fact that nuclear power is clean, safe, cheap and accepted as such by the industrially developed word. 62 refs., 13 figs
Nuclear matter equation of state including two-, three-, and four-nucleon correlations
Röpke, G.
2015-11-01
Light clusters (mass number A ≤4 ) in nuclear matter at subsaturation densities are described using a quantum statistical approach to calculate the quasiparticle properties and abundances of light elements. I review the formalism and approximations used and extend it with respect to the treatment of continuum correlations. Virial coefficients are derived from continuum contributions to the partial densities which depend on temperature, densities, and total momentum. The Pauli blocking is modified taking correlations in the medium into account. Both effects of continuum correlations lead to an enhancement of cluster abundances in nuclear matter at higher densities. Based on calculations for A =2 , estimates for the contributions with A =3 ,4 are given. The properties of light clusters and continuum correlations in dense matter are of interest for nuclear structure calculations, heavy-ion collisions, and astrophysical applications such as the formation of neutron stars in core-collapse supernovae.
Superheavy Elements --- A Probe for Nuclear Matter at the Extremes
Ackermann, D.
The spherical shell stabilised superheavy elements (SHE) predictedat the extreme of high Z and A are a nuclear structure phenomenon. They owe their existence to shell effects, an energy contribution of quantum mechanical origin to the nuclear potential, without which they would not be bound. Experimental activities in this field, apart from attempts to directly synthesise new elements, have to investigate reaction mechanism studies and, in particular, they have to pursue nuclear structure investigations to study the development of single particle levels towards the expected gaps for the proton (at Z = 114, 120 or 126) and neutron (at N = 184) shell closures in the region of spherical SHE. A number of exciting results in terms of the synthesis of new elements have reached the border of that region. In particular, the results obtained at the Flerov Laboratory of Nuclear Reactions (FLNR) for a rich number of decay patterns for ^{48}Ca induced reactions on actinide targets have by now been confirmed for reactions on ^{238}U, ^{244}Pu and ^{248}Cm at GSI, and on ^{242}Pu at LBNL. In recent years the development of efficient experimental set-ups, including separators and advanced particle and photon detection arrangements, allowed for more detailed nuclear structure studies for nuclei at and beyond Z = 100. Among the most interesting features is the observation of K-isomeric states. The heaviest example for such a structure feature was found in ^{270}Ds. In a recent experiment the knowledge on this nucleus and its decay products could be largely extended.
First measurement of nuclear recoil head-tail sense in a fiducialised WIMP dark matter detector
Battat, J. B. R.; Daw, E.; Ezeribe, A. C.; Gauvreau, J. -L.; Harton, J.L.; Lafler, R.; Lee, E. R.; Loomba, D.; Lumnah, A.; Miller, E. H.; Mouton, F.; Murphy, A. StJ.; Paling, S. M.; Phan, N. S.; Robinson, M.
2016-01-01
Recent computational results suggest that directional dark matter detectors have potential to probe for WIMP dark matter particles below the neutrino floor. The DRIFT-IId detector used in this work is a leading directional WIMP search time projection chamber detector. We report the first measurements of the detection of the directional nuclear recoils in a fully fiducialised low-pressure time projection chamber. In this new operational mode, the distance between each event vertex and the read...
Three flavor Nambu-Jona Lasinio model with Polyakov loop and competition with nuclear matter
Ciminale, M.; Gatto, R.; Ippolito, N. D.; Nardulli, G.; Ruggieri, M.
2007-01-01
We study the phase diagram of the three flavor Polyakov-Nambu-Jona Lasinio (PNJL) model and in particular the interplay between chiral symmetry restoration and deconfinement crossover. We compute chiral condensates, quark densities and the Polyakov loop at several values of temperature and chemical potential. Moreover we investigate on the role of the Polyakov loop dynamics in the transition from nuclear matter to quark matter.
Jet-induced modifications of the characteristic of the bulk nuclear matter
Marcinkowski, P; Kikoła, D; Sikorski, J; Porter-Sobieraj, J; Gawryszewski, P; Zygmunt, B
2015-01-01
We present our studies on jet-induced modifications of the characteristic of the bulk nuclear matter. To describe such a matter, we use efficient relativistic hydrodynamic simulations in (3+1) dimensions employing the Graphics Processing Unit (GPU) in the parallel programming framework. We use Cartesian coordinates in the calculations to ensure a high spatial resolution that is constant throughout the evolution of the system. We show our results on how jets modify the hydrodynamics fields and discuss the implications.
-matrix approach to the equation of state of dilute nuclear matter
Indian Academy of Sciences (India)
J N De; S K Samaddar; B K Agrawal
2014-04-01
Based on the general analysis of the grand canonical partition function in the -matrix framework, a method is presented to calculate the equation of state of dilute warm nuclear matter. The result is a model-independent virial series for the pressure and density that systematically includes contributions from all the ground and excited states of all the stable nuclear species and their scattering channels. The multiplicity distribution of these species to keep the matter in statistical equilibrium is found out and then the pressure, incompressibility and the symmetry energy of the system are evaluated. The calculated symmetry energy coefficients are found to be in fair agreement with the recent experimental data.
Institute of Scientific and Technical Information of China (English)
舒崧; 李家荣
2012-01-01
We used the Cornwall, Jackiw and Tomboulis （CJT） resummation scheme to study nuclear matter. In the CJT formalism the meson propagators are treated as the bare propagators and the the higher order loop corrections of the thermodynamic potential are evaluated at the Hartree approximation, while the vacuum fluctuations are ignored. Under these treatments in the CJT formalism we derived exact mean-field theory （MFT） results for the nuclear matter. The results are thermodynamically consistent, and our study indicates that the MFT result is the lowest order resummation result in the CJT resummation scheme. The relation between CJT formalism and MFT is clearly presented through the calculations.
Fermionic condensation in ultracold atoms, nuclear matter and neutron stars
Salasnich, Luca
2013-01-01
We investigate the Bose-Einstein condensation of fermionic pairs in three different superfluid systems: ultracold and dilute atomic gases, bulk neutron matter, and neutron stars. In the case of dilute gases made of fermionic atoms the average distance between atoms is much larger than the effective radius of the inter-atomic potential. Here the condensation of fermionic pairs is analyzed as a function of the s-wave scattering length, which can be tuned in experiments by using the technique of...
Appearance of the single gyroid network phase in "nuclear pasta" matter
Schuetrumpf, B.; Klatt, M. A.; Iida, K.; Schröder-Turk, G. E.; Maruhn, J. A.; Mecke, K.; Reinhard, P.-G.
2015-02-01
Nuclear matter under the conditions of a supernova explosion unfolds into a rich variety of spatially structured phases, called nuclear pasta. We investigate the role of periodic networklike structures with negatively curved interfaces in nuclear pasta structures, by static and dynamic Hartree-Fock simulations in periodic lattices. As the most prominent result, we identify for the first time the single gyroid network structure of cubic chiral I 4123 symmetry, a well-known configuration in nanostructured soft-matter systems, both as a dynamical state and as a cooled static solution. Single gyroid structures form spontaneously in the course of the dynamical simulations. Most of them are isomeric states. The very small energy differences from the ground state indicate its relevance for structures in nuclear pasta.
Pinning down nuclear. To the core of the matter
Energy Technology Data Exchange (ETDEWEB)
Boeck, Helmut; Gerstmayr, Michael [Technische Univ., Vienna (Austria); International Atomic Energy Agency, Vienna (Austria); Radde, Eileen [Nuclear Engineering Seibersdorf GmbH (Austria); International Atomic Energy Agency, Vienna (Austria)
2014-07-01
The nuclear disaster in Fukushima shocked the world tremendously. The call to pull out of nuclear energy is getting louder - and more often than not by politicians trying to lure the favour of voters. Through the media there are half-truths and false information floating about the global consequences of the disaster and sensational prognoses for the future, all of which are in turn unsettling for the general public. Are the opposers to nuclear energy playing with the fear of the public or is the threat real? This book tells, in a captivating manner - authenticated with examples and incidents not known by many - what the threat for the area actually looks like. They confront the level of truth in the frightening scenarios and inform about the situation in case of emergency. Furthermore, they examine factors that preceded the disaster and broach the subject of the incredible hunger for energy, which dominates the world and continues to drive the commercial use of nuclear energy. Also the ghost of Chernobyl and its aftermath, which has been dismissed from our minds, is re-examined based on current knowledge. The book impresses with insider know-how, latest detailed knowledge, amazing facts and an entertaining narrative style.
Isospin effects on collective nuclear dynamics
International Nuclear Information System (INIS)
We suggest several ways to study properties of the symmetry term in the nuclear equation of state, EOS, from collective modes in beta-unstable nuclei. After a general discussion on compressibility and saturation density in asymmetric nuclear matter we show some predictions on the collective response based on the solution of generalized Landau dispersion relations. Isoscalar-isovector coupling, disappearance of collectivity and possibility of new instabilities in low and high density regions are discussed with accent on their relation to the symmetry term of effective forces. The onset of chemical plus mechanical instabilities in a dilute asymmetric nuclear matter is discussed with reference to new features in fragmentation reactions
Nuclear-matter distributions of halo nuclei from elastic proton scattering in inverse kinematics
Energy Technology Data Exchange (ETDEWEB)
Egelhof, P.; Bauchet, A.; Fritz, S.; Geissel, H.; Gross, C.; Kraus, G.; Muenzenberg, G.; Neumaier, S.R.; Schaefer, T.; Scheidenberger, C. [Gesellschaft fuer Schwerionenforschung (GSI), D-64291 Darmstadt (Germany); Alkhazov, G.D.; Andronenko, M.N.; Gavrilov, G.E.; Khanzadeev, A.V.; Korolev, G.A.; Lobodenko, A.A.; Seliverstov, D.M.; Timofeev, N.A. [Petersburg Nuclear Physics Institute (PNPI), RU-188300 Gatchina (Russian Federation); Dobrovolsky, A.V. [Gesellschaft fuer Schwerionenforschung (GSI), D-64291 Darmstadt (Germany); Petersburg Nuclear Physics Institute (PNPI), RU-188300 Gatchina (Russian Federation); Mutterer, M. [Institut fuer Kernphysik (IKP), Technische Universitaet, D-64289 Darmstadt (Germany); Vorobyov, A.A.; Yatsoura, V.I.
2002-10-01
Proton-nucleus elastic scattering at intermediate energies, a well-established method for probing nuclear-matter density distributions of stable nuclei, was applied for the first time to exotic nuclei. This method is demonstrated to be an effective means for obtaining accurate and detailed information on the size and radial shape of halo nuclei. Absolute differential cross-sections for small-angle scattering were measured at energies near 700 MeV/u for the neutron-rich helium isotopes {sup 6}He and {sup 8}He, and more recently for the lithium isotopes {sup 6}Li, {sup 8}Li, {sup 9}Li and {sup 11}Li, using He and Li beams provided by the fragment separator FRS at GSI Darmstadt. Experiments were performed in inverse kinematics using the hydrogen-filled ionization chamber IKAR which served simultaneously as target and recoil-proton detector. For deducing nuclear-matter distributions, differential cross-sections calculated with the aid of the Glauber multiple-scattering theory, using various parametrizations for the nucleon density distributions as input, were fitted to the experimental cross-sections. The results on nuclear-matter radii and matter distributions are presented, and the significance of the data for a halo structure is discussed. Nuclear-matter distributions obtained for {sup 6}He and {sup 8}He conform with the concept that both nuclei compose of {alpha}-particle like cores and significant neutron halos. The matter distribution in {sup 11}Li exhibits, as expected from previous reaction cross-section studies with nuclear targets, the by far most extended halo component of all nuclei being investigated. In addition the present data allow a quantitative comparison of the structure of the He and Li isobars of either the mass number A=6 or A=8. The measured differential cross-sections have also been used for probing density distributions as predicted from various microscopic calculations. A few examples are presented. (orig.)
Pötzschner, B.; Mohamed, F.; Lichtinger, A.; Bock, D.; Rössler, E. A.
2015-10-01
We study a dynamically asymmetric binary glass former with the low-Tg component m-tri-cresyl phosphate (m-TCP: Tg = 206 K) and a spirobichroman derivative as a non-polymeric high-Tg component (Tg = 382 K) by means of 1H nuclear magnetic resonance (NMR), 31P NMR, and dielectric spectroscopy which allow component-selectively probing the dynamics. The entire concentration range is covered, and two main relaxation processes with two Tg are identified, Tg1 and Tg2. The slower one is attributed to the high-Tg component (α1-process), and the faster one is related to the m-TCP molecules (α2-process). Yet, there are indications that a small fraction of m-TCP is associated also with the α1-process. While the α1-relaxation only weakly broadens upon adding m-TCP, the α2-relaxation becomes extremely stretched leading to quasi-logarithmic correlation functions at low m-TCP concentrations—as probed by 31P NMR stimulated echo experiments. Frequency-temperature superposition does not apply for the α2-process and it reflects an isotropic, liquid-like motion which is observed even below Tg1, i.e., in the matrix of the arrested high-Tg molecules. As proven by 2D 31P NMR, the corresponding dynamic heterogeneities are of transient nature, i.e., exchange occurs within the distribution G(lnτα2). At Tg1 a crossover is found for the temperature dependence of (mean) τα2(T) from non-Arrhenius above to Arrhenius below Tg1 which is attributed to intrinsic confinement effects. This "fragile-to-strong" transition also leads to a re-decrease of Tg2(cm-TCP) at low concentration cm-TCP, i.e., a maximum is observed in Tg2(cm-TCP) while Tg1(cm-TCP) displays the well-known plasticizer effect. Although only non-polymeric components are involved, we re-discover essentially all features previously reported for polymer-plasticizer systems.
Energy Technology Data Exchange (ETDEWEB)
Pötzschner, B.; Mohamed, F.; Lichtinger, A.; Bock, D.; Rössler, E. A., E-mail: ernst.roessler@uni-bayreuth.de [Experimentalphysik II, Universität Bayreuth, 95440 Bayreuth (Germany)
2015-10-21
We study a dynamically asymmetric binary glass former with the low-T{sub g} component m-tri-cresyl phosphate (m-TCP: T{sub g} = 206 K) and a spirobichroman derivative as a non-polymeric high-T{sub g} component (T{sub g} = 382 K) by means of {sup 1}H nuclear magnetic resonance (NMR), {sup 31}P NMR, and dielectric spectroscopy which allow component-selectively probing the dynamics. The entire concentration range is covered, and two main relaxation processes with two T{sub g} are identified, T{sub g1} and T{sub g2}. The slower one is attributed to the high-T{sub g} component (α{sub 1}-process), and the faster one is related to the m-TCP molecules (α{sub 2}-process). Yet, there are indications that a small fraction of m-TCP is associated also with the α{sub 1}-process. While the α{sub 1}-relaxation only weakly broadens upon adding m-TCP, the α{sub 2}-relaxation becomes extremely stretched leading to quasi-logarithmic correlation functions at low m-TCP concentrations—as probed by {sup 31}P NMR stimulated echo experiments. Frequency-temperature superposition does not apply for the α{sub 2}-process and it reflects an isotropic, liquid-like motion which is observed even below T{sub g1}, i.e., in the matrix of the arrested high-T{sub g} molecules. As proven by 2D {sup 31}P NMR, the corresponding dynamic heterogeneities are of transient nature, i.e., exchange occurs within the distribution G(lnτ{sub α2}). At T{sub g1} a crossover is found for the temperature dependence of (mean) τ{sub α2}(T) from non-Arrhenius above to Arrhenius below T{sub g1} which is attributed to intrinsic confinement effects. This “fragile-to-strong” transition also leads to a re-decrease of T{sub g2}(c{sub m−TCP}) at low concentration c{sub m−TCP}, i.e., a maximum is observed in T{sub g2}(c{sub m−TCP}) while T{sub g1}(c{sub m−TCP}) displays the well-known plasticizer effect. Although only non-polymeric components are involved, we re-discover essentially all features previously
International Nuclear Information System (INIS)
We study a dynamically asymmetric binary glass former with the low-Tg component m-tri-cresyl phosphate (m-TCP: Tg = 206 K) and a spirobichroman derivative as a non-polymeric high-Tg component (Tg = 382 K) by means of 1H nuclear magnetic resonance (NMR), 31P NMR, and dielectric spectroscopy which allow component-selectively probing the dynamics. The entire concentration range is covered, and two main relaxation processes with two Tg are identified, Tg1 and Tg2. The slower one is attributed to the high-Tg component (α1-process), and the faster one is related to the m-TCP molecules (α2-process). Yet, there are indications that a small fraction of m-TCP is associated also with the α1-process. While the α1-relaxation only weakly broadens upon adding m-TCP, the α2-relaxation becomes extremely stretched leading to quasi-logarithmic correlation functions at low m-TCP concentrations—as probed by 31P NMR stimulated echo experiments. Frequency-temperature superposition does not apply for the α2-process and it reflects an isotropic, liquid-like motion which is observed even below Tg1, i.e., in the matrix of the arrested high-Tg molecules. As proven by 2D 31P NMR, the corresponding dynamic heterogeneities are of transient nature, i.e., exchange occurs within the distribution G(lnτα2). At Tg1 a crossover is found for the temperature dependence of (mean) τα2(T) from non-Arrhenius above to Arrhenius below Tg1 which is attributed to intrinsic confinement effects. This “fragile-to-strong” transition also leads to a re-decrease of Tg2(cm−TCP) at low concentration cm−TCP, i.e., a maximum is observed in Tg2(cm−TCP) while Tg1(cm−TCP) displays the well-known plasticizer effect. Although only non-polymeric components are involved, we re-discover essentially all features previously reported for polymer-plasticizer systems
Probing the Nuclear Symmetry Energy with Heavy-Ion Reactions Induced by Neutron-Rich Nuclei
Chen, Lie-Wen; Ko, Che Ming; Li, Bao-An; Yong, Gao-Chan
2007-01-01
Heavy-ion reactions induced by neutron-rich nuclei provide a unique means to investigate the equation of state of isospin-asymmetric nuclear matter, especially the density dependence of the nuclear symmetry energy. In particular, recent analyses of the isospin diffusion data in heavy-ion reactions have already put a stringent constraint on the nuclear symmetry energy around the nuclear matter saturation density. We review this exciting result and discuss its implications on nuclear effective ...
Nuclear matter properties from local chiral interactions with $\\Delta$ isobar intermediate states
Logoteta, Domenico; Kievsky, Alejandro
2016-01-01
Using two-nucleon and three-nucleon interactions derived in the framework of chiral perturbation theory (ChPT) with and without the explicit $\\Delta$ isobar contributions, we calculate the energy per particle of symmetric nuclear matter and pure neutron matter in the framework of the microscopic Brueckner-Hartree-Fock approach. In particular, we present for the first time nuclear matter calculations using the new fully local in coordinate-space two-nucleon interaction at the next-to-next-to-next-to-leading-order (N3LO) of ChPT with $\\Delta$ isobar intermediate states (N3LO$\\Delta$) recently developed by Piarulli et al. [arXiv:1606:06335]. We find that using this N3LO$\\Delta$ potential, supplemented with a local N2LO three-nucleon interaction with explicit $\\Delta$ isobar degrees of freedom, it is possible to obtain a satisfactory saturation point of symmetric nuclear matter. For this combination of two- and three-nucleon interactions we also calculate the nuclear symmetry energy and we compare our results wit...
Heavy-quark expansion for D and B mesons in nuclear matter
Directory of Open Access Journals (Sweden)
Buchheim Thomas
2014-01-01
Full Text Available The planned experiments at FAIR enable the study of medium modifications of D and B mesons in (dense nuclear matter. Evaluating QCD sum rules as a theoretical prerequisite for such investigations encounters heavy-light four-quark condensates. We utilize an extended heavy-quark expansion to cope with the condensation of heavy quarks.
Response of the XENON100 dark matter detector to nuclear recoils
E. Aprile; M. Alfonsi; . et al; A.P. Colijn; M.P. Decowski
2013-01-01
Results from the nuclear recoil calibration of the XENON100 dark matter detector installed underground at the Laboratori Nazionali del Gran Sasso, Italy are presented. Data from measurements with an external AmBe241 neutron source are compared with a detailed Monte Carlo simulation which is used to
Computational methods for the nuclear and neutron matter problems. Progress report
International Nuclear Information System (INIS)
A brief report is given of progress on the development of Monte Carlo methods for the treatment of both simplified and realistic models of extensive neutron and nuclear matter and, eventually, of finite nuclei. A wide class of algorithms that may allow the efficient sampling of the integrands required in calculating the energy expectations with useful trial wave functions was devised
Cold Nuclear Matter Effects on Open and Hidden Heavy Flavor Production at the LHC
Vogt, R
2015-01-01
We discuss a number of cold nuclear matter effects that can modify open heavy flavor and quarkonium production in proton-nucleus collisions and could thus also affect their production in nucleus-nucleus collisions, in addition to hot quark-gluon plasma production. We show some results for $p+$Pb collisions at sqrt s = 5 TeV at the LHC.
The nuclear symmetry energy and stability of matter in neutron star
Kubis, S
2006-01-01
It is shown that behavior of the nuclear symmetry energy is the key quantity in the stability consideration in neutron star matter. The symmetry energy controls the position of crust-core transition and also may lead to new effects in the inner core of neutron star.
Evidences for a new state of the nuclear matter: quark gluon plasma in liquid phase
International Nuclear Information System (INIS)
The experimental results obtained in the last years at the RHIC BNL (USA) allowed to obtain an important experimental result, namely the observation of the quark gluon plasma formation in nucleus-nucleus collisions at 200 A GeV in CMS. Evidences for this new state of nuclear matter are presented in this work. The results of the BRAHMS Experiment are detailed. (author)
Goldstone and Pseudo-Goldstone Bosons in Nuclear, Particle and Condensed-Matter Physics
Burgess, C. P.
1998-01-01
These notes review the effective lagrangian treatment of Goldstone and pseudo-Goldstone bosons, taking examples from high-energy/nuclear and condensed-matter physics. The contents are: 1. Goldstone Bosons 2. Pions: A Relativistic Application 3. Magnons: Nonrelativistic Applications 4. SO(5) Invariance and Superconductors 5. Bibliography
Di-nucleon structures in homogeneous nuclear matter based on two- and three-nucleon interactions
Arellano, H F; Rios, Arnau
2016-01-01
We investigate homogeneous nuclear matter within the Brueckner-Hartree-Fock (BHF) approach in the limits of isospin-symmetric nuclear matter (SNM) as well as pure neutron matter at zero temperature. The study is based on realistic representations of the internucleon interaction as given by Argonne v18, Paris, Nijmegen I and II potentials, in addition to chiral N$^{3}$LO interactions, including three-nucleon forces up to N$^{2}$LO. Particular attention is paid to the presence of di-nucleon bound states structures in $^1\\textrm{S}_0$ and $^3\\textrm{SD}_1$ channels, whose explicit account becomes crucial for the stability of self-consistent solutions at low densities. A characterization of these solutions and associated bound states is discussed. We confirm that coexisting BHF single-particle solutions in SNM, at Fermi momenta in the range $0.13-0.3$~fm$^{-1}$, is a robust feature under the choice of realistic internucleon potentials.
Study of Cold Nuclear Matter Effects on Heavy Quarkonia in Proton-Lead Collisions at LHCb
Jing, Fanfan; Yang, Zhenwei; Schmidt, Burkhard
Proton-nucleus ($p\\rm{A}$) collisions play an important role in high energy nuclear physics as they allow to study nuclear matter effects and the parton distribution functions in the nuclear environment (nPDF). The quantum chromodynamics (QCD) phase transition from hadron gas to the the quark-gluon plasma (QGP) is not expected to occur in a $p\\rm{A}$ collision due to its limited space-time size. Therefore, the $p\\rm{A}$ collisions provide an ideal platform to study cold nuclear matter (CNM) effects, which are also known as normal nuclear matter effects. The measurements of the productions and correlations of the final-state particles in $p\\rm{A}$ collisions serve the purpose to test various theoretical models for CNM effects, to constrain the benchmarking nPDFs, and thus provide a baseline to understand and interpret the QGP created in ultra-relativistic heavy-ion collisions. Heavy quarkonia (including charmonia and bottomonia), which are produced at the early stage of heavy-ion collisions, are considered goo...
Intrinsic neutron background of nuclear emulsions for directional Dark Matter searches
Aleksandrov, A; Buonaura, A; Consiglio, L; D'Ambrosio, N; De Lellis, G; Di Crescenzo, A; Di Marco, N; Di Vacri, M L; Furuya, S; Galati, G; Gentile, V; Katsuragawa, T; Laubenstein, M; Lauria, A; Loverre, P F; Machii, S; Monacelli, P; Montesi, M C; Naka, T; Pupilli, F; Rosa, G; Sato, O; Tioukov, V; Umemoto, A; Yoshimoto, M
2015-01-01
Recent developments of the nuclear emulsion technology led to the production of films with nanometric silver halide grains suitable to track low energy nuclear recoils with submicrometric length. This improvement opens the way to a directional Dark Matter detection, thus providing an innovative and complementary approach to the on-going WIMP searches. An important background source for these searches is represented by neutron-induced nuclear recoils that can mimic the WIMP signal. In this paper we provide an estimation of the contribution to this background from the intrinsic radioactive contamination of nuclear emulsions. We also report the induced background as a function of the read-out threshold, by using a GEANT4 simulation of the nuclear emulsion, showing that it amounts to about 0.02 neutrons per year per kilogram, fully compatible with the design of a 10 kg$\\times$year exposure.
Intrinsic neutron background of nuclear emulsions for directional Dark Matter searches
Alexandrov, A.; Asada, T.; Buonaura, A.; Consiglio, L.; D'Ambrosio, N.; De Lellis, G.; Di Crescenzo, A.; Di Marco, N.; Di Vacri, M. L.; Furuya, S.; Galati, G.; Gentile, V.; Katsuragawa, T.; Laubenstein, M.; Lauria, A.; Loverre, P. F.; Machii, S.; Monacelli, P.; Montesi, M. C.; Naka, T.; Pupilli, F.; Rosa, G.; Sato, O.; Strolin, P.; Tioukov, V.; Umemoto, A.; Yoshimoto, M.
2016-07-01
Recent developments of the nuclear emulsion technology led to the production of films with nanometric silver halide grains suitable to track low energy nuclear recoils with submicrometric length. This improvement opens the way to a directional Dark Matter detection, thus providing an innovative and complementary approach to the on-going WIMP searches. An important background source for these searches is represented by neutron-induced nuclear recoils that can mimic the WIMP signal. In this paper we provide an estimation of the contribution to this background from the intrinsic radioactive contamination of nuclear emulsions. We also report the neutron-induced background as a function of the read-out threshold, by using a GEANT4 simulation of the nuclear emulsion, showing that it amounts to about 0.06 per year per kilogram, fully compatible with the design of a 10 kg × year exposure.
A further update on possible crises in nuclear-matter theory
Dickhoff, W H
2015-01-01
The ancient problem of the saturation of symmetric nuclear matter is reviewed with an update on the status of the crises that were identified at an early stage by John Clark. We discuss how the initial problem with variational calculations providing more binding than the two hole-line contribution for the same interaction was overcome by calculations including three hole-line contributions without however reproducing the empirical nuclear saturation properties. It is argued that this remaining problem is still open because many solutions have been proposed or ad hoc adjustments implemented without generating universal agreement on the proper interpretation of the physics. The problem of nuclear saturation therefore persists leading to the necessity of an analysis of the way the nuclear saturation properties are obtained from experimental data. We clarify the role of short-range correlations and review results for nuclear saturation when such ingredients are completely taken into account using the Green's func...
Nuclear matter spectral function in the Bethe-Brueckner-Goldstone approach
Energy Technology Data Exchange (ETDEWEB)
Baldo, M.; Lo Monaco, L. [Dipartimento di Fisica dell' Universita di Catania, INFN, via S. Sofia 64, 95123, Catania (Italy)
2003-06-01
The microscopic many-body theory of the Nuclear Equation of State is discussed in the framework of the Bethe-Brueckner-Goldstone method. The expansion is extended up to the three hole-line diagrams contribution. Within the same scheme, the hole spectral function is calculated in nuclear matter to assess the relevance of nucleon-nucleon short-range correlations. The calculation is carried out by using several nucleon-nucleon realistic interactions. Results are compared with other approaches based on variational methods and transport theory. Discrepancies appear in the high-energy region, which is sensitive to short-range correlations, and are due to the different many-body treatment more than to the specific NN interaction used. Both nuclear matter Equation of State and spectral function appear to be dominated by two-body correlations. (orig.)
Calculation of nuclear matter in the presence of strong magnetic field using LOCV technique
Bordbar, G H
2015-01-01
In the present work, we are interested in the properties of nuclear matter at zero temperature in the presence of strong magnetic fields using the lowest order constraint variational (LOCV) method employing $AV_{18}$ nuclear potential. Our results indicate that in the absence of a magnetic field, the energy per particle is a symmetric function of the spin polarization parameter. This shows that for the nuclear matter, the spontaneous phase transition to a ferromagnetic state does not occur. However, we have found that for the magnetic fields $ B\\gtrsim 10 ^ {18}\\ G$, the symmetry of energy is broken and the energy has a minimum at a positive value of the spin polarization parameter. We have also found that the effect of magnetic field on the value of energy is more significant at the low densities. Our calculations show that at lower densities, the spin polarization parameter is more sensitive to the magnetic field.
Cold Nuclear Matter Effects on J/psi Production: Intrinsic and Extrinsic Transverse Momentum Effects
Energy Technology Data Exchange (ETDEWEB)
Ferreiro, E.G.; /Santiago de Compostela U.; Fleuret, F.; /Ecole Polytechnique; Lansberg, J.P.; /Heidelberg U.; Rakotozafindrabe, A.; /SPhN, DAPNIA, Saclay
2010-08-26
Cold nuclear matter effects on J/{psi} production in proton-nucleus and nucleus-nucleus collisions are evaluated taking into account the specific J/{psi}-production kinematics at the partonic level, the shadowing of the initial parton distributions and the absorption in the nuclear matter. We consider two different parton processes for the c{bar c}-pair production: one with collinear gluons and a recoiling gluon in the final state and the other with initial gluons carrying intrinsic transverse momentum. Our results are compared to RHIC observables. The smaller values of the nuclear modification factor R{sub AA} in the forward rapidity region (with respect to the mid rapidity region) are partially explained, therefore potentially reducing the need for recombination effects.
Onset of nuclear matter expansion in Au+Au collisions
Crochet, Philippe; Gobbi, A; Donà, R; Coffin, J P; Fintz, P; Guillaume, G; Jundt, F; Kühn, C E; Roy, C; De Schauenburg, B; Tizniti, L; Wagner, P; Alard, J P; Amouroux, V; Andronic, A; Basrak, Z; Bastid, N; Belyaev, I; Best, D; Biegansky, J; Butà, A; Caplar, R; Cindro, N; Dupieux, P; Dzelalija, M; Fan, Z G; Fodor, Z; Fraysse, L; Freifelder, R P; Herrmann, N; Hildenbrand, K D; Hong, B H; Jeong, S C; Kecskeméti, J; Kirejczyk, M; Koncz, P; Korolija, M; Kotte, R; Lebedev, A; Leifels, Y; Man'ko, V I; Moisa, D; Mösner, J; Neubert, W; Pelte, D; Petrovici, M; Pinkenburg, C H; Pras, P; Ramillien, V; Reisdorf, W; Ritman, J L; Sadchikov, A G; Schüll, D; Seres, Z; Sikora, B; Simion, V; Siwek-Wilczynska, K; Sodan, U; Teh, K M; Trzaska, M; Vasilev, M A; Wang, G S; Wessels, J P; Wienold, T; Wisniewski, K; Wohlfarth, D; Zhilin, A V
1997-01-01
Using the FOPI detector at GSI Darmstadt, excitation functions of collective flow components were measured for the Au+Au system, in the reaction plane and out of this plane, at seven incident energies ranging from 100AMeV to 800AMeV. The threshold energies, corresponding to the onset of sideward-flow (balance energy) and squeeze-out effect (transition energy), are extracted from extrapolations of these excitation functions toward lower beam energies for charged products with Z>2. The transition energy is found to be larger than the balance energy. The impact parameter dependence of both balance and transition energies, when extrapolated to central collisions, suggests comparable although slightly higher values than the threshold energy for the radial flow. The relevant parameter seems to be the energy deposited into the system in order to overcome the attractive nuclear forces.
Specific Heat of Matter Formed in Relativistic Nuclear Collisions
Basu, Sumit; Chatterjee, Rupa; Nayak, Tapan K; Nandi, Basanta K
2016-01-01
We report the excitation energy dependence of specific heat (\\cv) of hadronic matter at freeze-out in Au+Au and Cu+Cu collisions at the Relativistic Heavy Ion Collider energies by analyzing the published data on event-by-event mean transverse momentum (\\meanpt) distributions. The \\meanpt~distributions in finite \\pt~ranges are converted to distributions of effective temperatures, and dynamical fluctuations in temperature are extracted by subtracting widths of the corresponding mixed event distributions. The heat capacity per particle at the kinetic freezeout surface is presented as a function of collision energy, which shows a sharp rise in \\cv~below \\sNN~=~62.4~GeV. We employ the Hadron Resonance Gas (HRG) model to estimate \\cv~at the chemical and kinetic freezeout surfaces. The experimental results are compared to the HRG and other theoretical model calculations. HRG results show good agreement with data. Model predictions for \\cv~at the Large Hadron Collider energy are presented.
Energy-Momentum Tensor Form Factors of the Nucleon in Nuclear Matter in the Chiral Soliton Model
Yakhshiev, Ulugbek; Kim, Hyun-Chul; Schweitzer, Peter
2013-08-01
In the present talk, we report a recent investigation on the nucleon form factors of the energy-momentum tensor in nuclear matter, based on the in-medium modified chiral soliton model. The results in free space are in agreement with those from other approaches. We have discussed the changes of the energy-momentum tensor form factors in nuclear matter and the modification of the soliton structure due to the surrounding nuclear environment.
Energy Technology Data Exchange (ETDEWEB)
NONE
2006-07-15
The object of this work is since its first edition in 1983 under the title 'Collection of nuclear activities legislation and regulation ' to realize an ordered collection of texts constituting the juridical and institutional frame of nuclear activities, gathering the legislative, regulatory and technical texts; the international, European and national texts. Aiming to include the whole of the atom applications, this collection tackles various themes, in ten chapters.The volume number two includes the following chapters: nuclear matters and ionizing radiations sources; wastes. Previously edited by the Cea, that realizes it it is now published in the collection 'Legislation and regulation' of officials journals editions. (N.C.)
A further update on possible crises in nuclear-matter theory
Dickhoff, W. H.
2016-03-01
The ancient problem of the saturation of symmetric nuclear matter is reviewed with an update on the status of the crises that were identified at an early stage by John Clark. We discuss how the initial problem with variational calculations providing more binding than the two hole-line contribution for the same interaction was overcome by calculations including three hole-line contributions without however reproducing the empirical nuclear saturation properties. It is argued that this remaining problem is still open because many solutions have been proposed or ad hoc adjustments implemented without generating universal agreement on the proper interpretation of the physics. The problem of nuclear saturation therefore persists leading to the necessity of an analysis of the way the nuclear saturation properties are obtained from experimental data. We clarify the role of short-range correlations and review results for nuclear saturation when such ingredients are completely taken into account using the Green’s function method. The role of long-range correlations is then analyzed with special emphasis on the importance of attractive pion-dominated excitation modes which inevitably lead to higher saturation densities than observed. Because such modes have no counterpart in finite nuclear systems, it is therefore argued that they should not be considered when calculating nuclear matter properties. The remaining open question is then whether long-range correlations in finite nuclei which in turn have no counterpart in infinite matter, represent the remaining missing ingredient in this analysis. We also briefly comment on the role of three-body interactions in the context of the dispersive optical model description of experimental data. It is further noted that interactions based on chiral perturbation theory at present do not generate a sufficient number of high-momentum nucleons leading to radii that are too small and substantial overbinding in finite nuclei.
Density of Saturated Nuclear Matter at Large $N_{c}$ and Heavy Quark Mass Limits
Adhikari, Prabal; Datta, Ishaun
2013-01-01
We exhibit the existence of stable, saturated nuclear matter in the large $N_{c}$ and heavy quark mass limits of QCD. In this limit, baryons (with the same spin flavor structure) interact at leading order in $N_{c}$ via a repulsive interaction due to the Pauli exclusion principle and at subleading order in $1/N_c$ via the exchange of glueballs. Assuming that the lightest glueball is a scalar, which implies that the subleading baryon interaction is attractive, we find that nuclear matter saturates since the subleading attractive interaction is longer ranged than the leading order repulsive one. We find that the saturated matter is in the form of a crystal with either a face-centered cubic or a hexagonal-close-packed symmetry with baryon densities of $\\mathcal{O}((\\, \\tilde{\\alpha}_{s} m_q (\\ln (N_{c}m_{q}\\Lambda_{\\textrm{QCD}}^{-1}))^{-1})^3 )$. Remarkably, the leading order expression for the density of saturated nuclear matter is independent of the lighest glueball mass and scalar-glueball-baryon coupling in...
International Nuclear Information System (INIS)
In this contribution, we review the most important physics presented originally in our recent publications. Some new analyses, insights and perspectives are also provided. We showed recently that the symmetry energy Esym (ρ) and its density slope L(ρ) at an arbitrary density ρ can be expressed analytically in terms of the magnitude and momentum dependence of the single-nucleon potentials using the Hugenholtz-Van Hove (HVH) theorem. These relationships provide new insights about the fundamental physics governing the density dependence of nuclear symmetry energy. Using the isospin and momentum (k) dependent MDI interaction as an example, the contribution of different terms in the single-nucleon potential to the Esym (ρ) and L(ρ) are analyzed in detail at different densities. It is shown that the behavior of Esym is mainly determined by the first-order symmetry potential Usym,1(ρ, k) of the single-nucleon potential. The density slope L(ρ) depends not only on the first-order symmetry potential Usym,1(ρ, k) but also on the second-order one Usym,2(ρ, k). Both the Usym,1(ρ, k) and Usym,2(ρ, k) at normal density ρ 0 are constrained by the isospin- and momentum-dependent nucleon optical potential extracted from the available nucleon-nucleus scattering data. The Usym,2(ρ, k) especially at high density and momentum affects significantly the L(ρ), but it is theoretically poorly understood and currently there is almost no experimental constraints known. (orig.)
Nuclear matter saturation with chiral three-nucleon interactions fitted to light nuclei properties
Logoteta, Domenico; Bombaci, Ignazio; Kievsky, Alejandro
2016-07-01
The energy per particle of symmetric nuclear matter and pure neutron matter is calculated using the many-body Brueckner-Hartree-Fock approach and employing the Chiral Next-to-next-to-next-to leading order (N3LO) nucleon-nucleon (NN) potential, supplemented with various parametrizations of the Chiral Next-to-next-to leading order (N2LO) three-nucleon interaction. Such combination is able to reproduce several observables of the physics of light nuclei for suitable choices of the parameters entering in the three-nucleon interaction. We find that some of these parametrizations provide a satisfactory saturation point of symmetric nuclear matter and values of the symmetry energy and its slope parameter L in very good agreement with those extracted from various nuclear experimental data. Thus, our results represent a significant step toward a unified description of few- and many-body nuclear systems starting from two- and three-nucleon interactions based on the symmetries of QCD.
2011-03-02
... From the Federal Register Online via the Government Publishing Office NUCLEAR REGULATORY COMMISSION In the Matter of Progress Energy Florida, Inc. (Combined License Application, Levy County Nuclear... relating to pending appeal filed by the Nuclear Regulatory Commission staff in this case. Mr. Dehmel...
The Imaginary Part of Nucleon Self-energy in hot nuclear matter
Alvarez-Ruso, L; Oset, E
1996-01-01
A semiphenomenological approach to the nucleon self-energy in nuclear matter at finite temperatures is followed. It combines elements of Thermo Field Dynamics for the treatment of finite temperature with a model for the self-energy, which evaluates the second order diagrams taking the needed dynamics of the NN interaction from experiment. The approach proved to be accurate at zero temperature to reproduce Im(Sigma) and other properties of nucleons in matter. In the present case we apply it to determine Im(Sigma) at finite temperatures. An effective NN cross section is deduced which can be easily used in analyses of heavy ion reactions.
From chiral Lagrangians to Landau Fermi liquid theory of nuclear matter
International Nuclear Information System (INIS)
A simple relation between the effective parameters of chiral Lagrangians in medium as predicted by BR scaling and Landau Fermi liquid parameters is derived. This provides a link between an effective theory of QCD at mean-field level and many-body theory of nuclear matter. It connects in particular the scaling vector-meson mass probed by dileptons produced in heavy-ion collisions (e.g., CERES of CERN-SPS) to the scaling nucleon-mass relevant for low-energy spectroscopic properties, e.g., the nuclear gyromagnetic ratios δg1 and the effective axial-vector constant g*A. (orig.)
Magnetic Moments of Octet Baryons in Hot and Dense Nuclear Matter
Singh, Harpreet; Dahiya, Harleen
2016-01-01
We have calculated the in-medium magnetic moments of octet baryons in the presence of hot and dense symmetric nuclear matter. Effective magnetic moments of baryons have been derived from medium modified quark masses within chiral SU(3) quark mean field model.Further, for better insight of medium modification of baryonic magnetic moments, we have considered the explicit contributions from the valence as well as sea quark effects. These effects have been successful in giving the description of baryonic magnetic moments in vacuum. The magnetic moments of baryons are found to vary significantly as a function of density of nuclear medium.
Three-body Effect on Equation of State of Spin-polarized Nuclear Matter
Institute of Scientific and Technical Information of China (English)
ZuoWei
2003-01-01
The equation of state (EOS) of spin-polarized nuclear matter has been investigated within the spin-dependent; Brueckner-Hartree-Fock framework by adopting the realistic nucleon-nucleon interaction supplemented with a microscopic three-body force. The three-body force effects have been studied and stressed with a special attention. The calculated results are given in Fig.1. It is seen that; in the Brueckner-Hartree-Fock framework the predicted energy per particle of spin-polarized nuclear matter versus the neutron and proton spin-polarization parameters fulfills a quadratic law in the whole range of spin-polarization. The related physical quantities such as spin the Landau parameters Go in spin channel and G′0 in spin-isospin channel, have been also calculated.
Energy Technology Data Exchange (ETDEWEB)
Schenley, R.L.; Griest, W.H.
1990-08-01
Environmental Protection Agency (EPA) methodology for regulatory organics fails to account for the organic matter that is suggested by total organic carbon (TOC) analysis in the Oak Ridge National Laboratory (ORNL) inactive nuclear waste-tank liquids and sludges. Identification and measurement of the total organics are needed to select appropriate waste treatment technologies. An initial investigation was made of the nature of the organics in several waste-tank liquids. This report details the analysis of ORNL wastes.
Quark-Meson Coupling Model, Nuclear Matter Constraints and Neutron Star Properties
Whittenbury, D. L.; Carroll, J D; Thomas, A. W.; Tsushima, K; Stone, J. R.
2013-01-01
We explore the equation of state for nuclear matter in the quark-meson coupling model, including full Fock terms. The comparison with phenomenological constraints can be used to restrict the few additional parameters appearing in the Fock terms which are not present at Hartree level. Because the model is based upon the in-medium modification of the quark structure of the bound hadrons, it can be applied without additional parameters to include hyperons and to calculate the equation of state o...
NDM06: 2. symposium on neutrinos and dark matter in nuclear physics
Energy Technology Data Exchange (ETDEWEB)
Akerib, D.; Arnold, R.; Balantekin, A.; Barabash, A.; Barnabe, H.; Baroni, S.; Baussan, E.; Bellini, F.; Bobisut, F.; Bongrand, M.; Brofferio, Ch.; Capolupo, A.; Carrara Enrico; Caurier, E.; Cermak, P.; Chardin, G.; Civitarese, O.; Couchot, F.; Kerret, H. de; Heros, C. de los; Detwiler, J.; Dracos, M.; Drexlin, G.; Efremenko, Y.; Ejiri, H.; Falchini, E.; Fatemi-Ghomi, N.; Finger, M.Ch.; Finger Miroslav, Ch.; Fiorillo, G.; Fiorini, E.; Fracasso, S.; Frekers, D.; Fushimi, K.I.; Gascon, J.; Genest, M.H.; Georgadze, A.; Giuliani, A.; Goeger-Neff, M.; Gomez-Cadenas, J.J.; Greenfield, M.; H de Jesus, J.; Hallin, A.; Hannestad, St.; Hirai, Sh.; Hoessl, J.; Ianni, A.; Ieva, M.B.; Ishihara, N.; Jullian, S.; Kaim, S.; Kajino, T.; Kayser, B.; Kochetov, O.; Kopylov, A.; Kortelainen, M.; Kroeninger, K.; Lachenmaier, T.; Lalanne, D.; Lanfranchi, J.C.; Lazauskas, R.; Lemrani, A.R.; Li, J.; Mansoulie, B.; Marquet, Ch.; Martinez, J.; Mirizzi, A.; Morfin Jorge, G.; Motz, H.; Murphy, A.; Navas, S.; Niedermeier, L.; Nishiura, H.; Nomachi, M.; Nones, C.; Ogawa, H.; Ogawa, I.; Ohsumi, H.; Palladino, V.; Paniccia, M.; Perotto, L.; Petcov, S.; Pfister, S.; Piquemal, F.; Poves, A.; Praet, Ch.; Raffelt, G.; Ramberg, E.; Rashba, T.; Regnault, N.; Ricol, J.St.; Rodejohann, W.; Rodin, V.; Ruz, J.; Sander, Ch.; Sarazin, X.; Scholberg, K.; Sigl, G.; Simkovic, F.; Sousa, A.; Stanev, T.; Strolger, L.; Suekane, F.; Thomas, J.; Titov, N.; Toivanen, J.; Torrente-Lujan, E.; Tytler, D.; Vala, L.; Vignaud, D.; Vitiello, G.; Vogel, P.; Volkov, G.; Volpe, C.; Wong, H.; Yilmazer, A
2006-07-01
This second symposium on neutrinos and dark matter is aimed at discussing research frontiers and perspectives on currently developing subjects. It has been organized around 6 topics: 1) double beta decays, theory and experiments (particularly: GERDA, MOON, SuperNEMO, CUORE, CANDLES, EXO, and DCBA), 2) neutrinos and nuclear physics, 3) single beta decays and nu-responses, 4) neutrino astrophysics, 5) solar neutrino review, and 6) neutrino oscillations. This document is made up of the slides of the presentations.
Dynamical properties of nuclear and stellar matter and the symmetry energy
Pais, Helena; Santos, Alexandre; Brito, Lucília; Providência, Constan\\c c a
2010-01-01
The effects of density dependence of the symmetry energy on the collective modes and dynamical instabilities of cold and warm nuclear and stellar matter are studied in the framework of relativistic mean-field hadron models. The existence of the collective isovector and possibly an isoscalar collective mode above saturation density is discussed. It is shown that soft equations of state do not allow for a high density isoscalar collective mode, however, if the symmetry energy is hard enough an ...
A. De PaceIstituto Nazionale di Fisica Nucleare, Sezione di Torino
2015-01-01
Many-body techniques for the calculation of quasielastic nuclear matter response functions in the fully antisymmetrized random phase approximation on a Hartree-Fock basis are discussed in detail. The methods presented here allow for an accurate evaluation of the response functions with little numerical effort. Formulae are given for a generic non-relativistic potential parameterized in terms of meson exchanges; on the other hand, relativistic kinematical effects have been accounted for.
International Nuclear Information System (INIS)
Many-body techniques for the calculation of quasi-elastic nuclear matter response functions in the fully antisymmetrized random phase approximation on a Hartree-Fock basis are discussed in detail. The methods presented here allow for an accurate evaluation of the response functions with little numerical effort. Formulae are given for a generic non-relativistic potential parameterized in terms of meson exchanges; on the other hand, relativistic kinematical effects have been accounted for. (orig.)
Sun, Bao-Xi; Lu, Xiao-Fu; Shen, Peng-Nian; Zhao, En-Guang
2002-01-01
The Debye screening masses of the $\\sigma$, $\\omega$ and neutral $\\rho$ mesons and the photon are calculated in the relativistic mean-field approximation. As the density of the nucleon increases, all the screening masses of mesons increase. It shows a different result with Brown-Rho scaling, which implies a reduction in the mass of all the mesons in the nuclear matter except the pion. Replacing the masses of the mesons with their corresponding screening masses in Walecka-1 model, five saturat...
Spinodal Instabilities in Nuclear Matter in a Stochastic Relativistic Mean-Field Approach
Ayik, S.; Yilmaz, O.; Er, N.; Gokalp, A.; Ring, P.
2009-01-01
Spinodal instabilities and early growth of baryon density fluctuations in symmetric nuclear matter are investigated in the basis of stochastic extension of relativistic mean-field approach in the semi-classical approximation. Calculations are compared with the results of non-relativistic calculations based on Skyrme-type effective interactions under similar conditions. A qualitative difference appears in the unstable response of the system: the system exhibits most unstable behavior at higher...
International Nuclear Information System (INIS)
In this work it is proposed an extension of the relativistic Quantum Hadrodynamic theory (QHD) to the study of nucleonic pairing in nuclear matter. The work follows the usual formulation of QHD by describing the NN-interaction in terms of mean fields either for the usual self-energy, Σ, or the pairing energy, Δ. The equations of the fields are obtained in terms of the exact nucleon propagators which are expanded up to the first order in the NN-interaction, defining the self-consistent Hartree-Fock-Bogoliubov (HFB) approximation for Σ and Δ. This approach represents an improvement over the old non-relativistic formulations in the sense that it allows for a simultaneous description of many nuclear matter properties as the saturation point, the effective mass of the nucleon, the energy gap in the sp-spectrum, etc., in a consistent fashion, by considering only the hadronic degrees of freedom, what that is, the nucleons interacting in nuclear matter through the exchange of mesons. The resulting mean field energies, Σ and Δ, have large components in the Lorentz space, which adequately cancel each other in the expressions of either the energy per nucleon or the gap parameter, so that resulting values of these quantities agree with the experimental data. Although the gap parameter can be adequately estimated with non-relativistic models, in terms of two nucleon interactions, the saturation point of nuclear matter cannot be. The appealing feature of the present model is its rather simple fundamental formulation in terms of hadronic degrees of freedom and the usual HFB approximation to the many-body field theory, which points toward future improvements as would be obtained with a self-consistent Brueckner-HF approximation. (author). 102 refs., 39 figs., 9 tabs
Chiral approach to nuclear matter: Role of explicit short-range NN-terms
Fritsch, S
2003-01-01
We extend a recent chiral approach to nuclear matter by including the most general (momentum-independent) NN-contact interaction. Iterating this two-parameter contact-vertex with itself and with one-pion exchange the emerging energy per particle exhausts all terms possible up-to-and-including fourth order in the small momentum expansion. The equation of state of pure neutron matter, $\\bar E_n(k_n)$, can be reproduced very well up to quite high neutron densities of $\\rho_n=0.5\\fmd$ by adjusting the strength of a repulsive $nn$-contact interaction. Binding and saturation of isospin-symmetric nuclear matter is a generic feature of our perturbative calculation. Fixing the maximum binding energy per particle to $-\\bar E(k_{f0})= 15.3 $MeV we find that any possible equilibrium density $\\rho_0$ lies below $\\rho_0^{\\rm max}=0.191\\fmd$. The additional constraint from the neutron matter equation of state leads however to a somewhat too low saturation density of $\\rho_0 =0.134 \\fmd$. We also investigate the effects of t...
Constraining mean-field models of the nuclear matter equation of state at low densities
Voskresenskaya, M. D.; Typel, S.
2012-08-01
An extension of the generalized relativistic mean-field (gRMF) model with density dependent couplings is introduced in order to describe thermodynamical properties and the composition of dense nuclear matter for astrophysical applications. Bound states of light nuclei and two-nucleon scattering correlations are considered as explicit degrees of freedom in the thermodynamical potential. They are represented by quasiparticles with medium-dependent properties. The model describes the correct low-density limit given by the virial equation of state (VEoS) and reproduces RMF results around nuclear saturation density where clusters are dissolved. A comparison between the fugacity expansions of the VEoS and the gRMF model provides consistency relations between the quasiparticles properties, the nucleon-nucleon scattering phase shifts and the meson-nucleon couplings of the gRMF model at zero density. Relativistic effects are found to be important at temperatures that are typical in astrophysical applications. Neutron matter and symmetric nuclear matter are studied in detail.
Exploring the nuclear pasta phase in Core-Collapse Supernova Matter
Energy Technology Data Exchange (ETDEWEB)
Pais, Helena [University of Tennessee, Knoxville (UTK); Stone, Jirina R [ORNL
2012-01-01
The core-collapse supernova (CCSN) phenomenon, one of the most explosive events in the Uni- verse, presents a challenge to theoretical astrophysics. Of the large variety of forms of matter present in CCSN, we focus on the transitional region between homogeneous and inhomogeneous phases. Traditionally, here the nuclear structures undergo a series of changes in shape from spher- ical to exotic deformed forms: rods, slabs, cylindrical holes and bubbles, termed nuclear pasta . A fully self-consistent three-dimensional, finite temperature Skyrme-Hartree-Fock + BCS (SHF) calculation yields, for the first time, the critical density and temperature of both the onset of the pasta in inhomogeneous matter, consisting of neutron heavy nuclei and a free neutron and electron gas, and its dissolution in to a homogeneous neutron, proton and electron liquid. As the nuclear matter properties depend on the effective nucleon-nucleon interaction in the SHF model, we employ four different forms of the Skyrme interaction, SkM , SLy4, NRAPR and SQMC700 and find subtle variations in the low density and high density transitions into and out of the pasta phase. Two new stable pasta shapes have been identified, in addition to the classic ones, on the grid of densities and temperatures used in this work. Detailed examination and clasification of the transitions found will form the content of a forthcoming publication.
Nuclear forces and their impact on neutron-rich nuclei and neutron-rich matter
Hebeler, K; Menendez, J; Schwenk, A
2015-01-01
We review the impact of nuclear forces on matter at neutron-rich extremes. Recent results have shown that neutron-rich nuclei become increasingly sensitive to three-nucleon forces, which are at the forefront of theoretical developments based on effective field theories of quantum chromodynamics. This includes the formation of shell structure, the spectroscopy of exotic nuclei, and the location of the neutron dripline. Nuclear forces also constrain the properties of neutron-rich matter, including the neutron skin, the symmetry energy, and the structure of neutron stars. We first review our understanding of three-nucleon forces and show how chiral effective field theory makes unique predictions for many-body forces. Then, we survey results with three-nucleon forces in neutron-rich oxygen and calcium isotopes and neutron-rich matter, which have been explored with a range of many-body methods. Three-nucleon forces therefore provide an exciting link between theoretical, experimental and observational nuclear physi...
New Kohn-Sham density functional based on microscopic nuclear and neutron matter equations of state
Baldo, M.; Robledo, L. M.; Schuck, P.; Viñas, X.
2013-06-01
A new version of the Barcelona-Catania-Paris energy functional is applied to a study of nuclear masses and other properties. The functional is largely based on calculated ab initio nuclear and neutron matter equations of state. Compared to typical Skyrme functionals having 10-12 parameters apart from spin-orbit and pairing terms, the new functional has only 2 or 3 adjusted parameters, fine tuning the nuclear matter binding energy and fixing the surface energy of finite nuclei. An energy rms value of 1.58 MeV is obtained from a fit of these three parameters to the 579 measured masses reported in the Audi and Wapstra [Nucl. Phys. ANUPABL0375-947410.1016/j.nuclphysa.2003.11.003 729, 337 (2003)] compilation. This rms value compares favorably with the one obtained using other successful mean field theories, which range from 1.5 to 3.0 MeV for optimized Skyrme functionals and 0.7 to 3.0 for the Gogny functionals. The other properties that have been calculated and compared to experiment are nuclear radii, the giant monopole resonance, and spontaneous fission lifetimes.
General aspects of the nucleon-nucleon interaction and nuclear matter properties
Energy Technology Data Exchange (ETDEWEB)
Plohl, Oliver
2008-07-25
The subject of the present thesis is at first the investigation of model independent properties of the nucleon-nucleon (NN) interaction in the vacuum concerning the relativistic structure and the implications for nuclear matter properties. Relativistic and non-relativistic meson-exchange potentials, phenomenological potentials s well as potentials based on effective field theory (EFT) are therefore mapped on a relativistic operator basis given by the Clifford Algebra. This allows to compare the various approaches at the level of covariant amplitudes where a remarkable agreement is found. Furthermore, the relativistic self-energy is determined in the Hartree-Fock (HF) approximation. The appearance of a scalar and vector field of several hundred MeV magnitude is a general feature of relativistic descriptions of nuclear matter. Within QCD sum rules these fields arise due to the density dependence of chiral condensates. We find that independent of the applied NN interaction large scalar and vector fields are generated when the symmetries of the Lorentz group are restored. In the framework of chiral EFT (chEFT) it is shown, that these fields are generated by short-range next-to-leading order (NLO) contact terms, which are connected to the spin-orbit interaction. To estimate the effect arising from NN correlations the equation of state of nuclear and neutron matter is calculated in the Brueckner-HF (BHF) approximation applying chEFT. Although, as expected, a clear over-binding is found (at NLO a saturating behavior is observed), the symmetry energy shows realistic properties when compared to phenomenological potentials (within the same approximation) and other approaches. The investigation of the pion mass dependence within chEFT at NLO shows that the magnitude of the scalar and vector fields persists in the chiral limit - nuclear matter is still bound. In contrast to the case of a pion mass larger than the physical one the binding energy and saturation density are
Hu, Jinniu; Shen, Hong
2016-01-01
We study the properties of nuclear matter with lattice nucleon-nucleon ($NN$) potential in the relativistic Brueckner-Hartree-Fock (RBHF) theory. To use this potential in such a microscopic many-body theory, we firstly have to construct a one-boson-exchange potential (OBEP) based on the latest lattice $NN$ potential. Three mesons, pion, $\\sigma$ meson, and $\\omega$ meson, are considered. Their coupling constants and cut-off momenta are determined by fitting the on-shell behaviors and phase shifts of the lattice force, respectively. Therefore, we obtain two parameter sets of the OBEP potential (named as LOBEP1 and LOBEP2) with these two fitting ways. We calculate the properties of symmetric and pure neutron matter with LOBEP1 and LOBEP2. In non-relativistic Brueckner-Hartree-Fock case, the binding energies of symmetric nuclear matter are around $-3$ and $-5$ MeV at saturation densities, while it becomes $-8$ and $-12$ MeV in relativistic framework with $^1S_0,~^3S_1,$ and $^3D_1$ channels using our two paramet...
Systematic analysis of the incoming quark energy loss in cold nuclear matter
Song, Li-Hua; Liu, Na
2012-01-01
The investigation into the fast parton energy loss in cold nuclear matter is crucial for a good understanding of the parton propagation in hot-dense medium. By means of four typical sets of nuclear parton distributions and three parametrizations of quark energy loss, the parameter values in quark energy loss expressions are determined from a leading order statistical analysis of the existing experimental data on nuclear Drell-Yan differential cross section ratio as a function of the quark momentum fraction. It is found that with independence on the nuclear modification of parton distributions, the available experimental data from lower incident beam energy rule out the incident-parton momentum fraction quark energy loss. Whether the quark energy loss is linear or quadratic with the path length is not discriminated. The global fit of all selected data gives the quark energy loss per unit path length {\\alpha} = 1.21\\pm0.09 GeV/fm by using nuclear parton distribution functions determined only by means of the wor...
Inoue, Takashi; Aoki, Sinya; Doi, Takumi; Hatsuda, Tetsuo; Ikeda, Yoichi; Ishii, Noriyoshi; Murano, Keiko; Nemura, Hidekatsu; Sasaki, Kenji
2013-09-13
Quark mass dependence of the equation of state (EOS) for nucleonic matter is investigated, on the basis of the Brueckner-Hartree-Fock method with the nucleon-nucleon interaction extracted from lattice QCD simulations. We observe saturation of nuclear matter at the lightest available quark mass corresponding to the pseudoscalar meson mass ≃469 MeV. Mass-radius relation of the neutron stars is also studied with the EOS for neutron-star matter from the same nuclear force in lattice QCD. We observe that the EOS becomes stiffer and thus the maximum mass of neutron star increases as the quark mass decreases toward the physical point.
Equation of state of the neutron star matter, and the nuclear symmetry energy
Loan, Doan Thi; Khoa, Dao T; Margueron, Jerome
2011-01-01
The nuclear mean-field potentials obtained in the Hartree-Fock method with different choices of the in-medium nucleon-nucleon (NN) interaction have been used to study the equation of state (EOS) of the neutron star (NS) matter. The EOS of the uniform NS core has been calculated for the np$e\\mu$ composition in the $\\beta$-equilibrium at zero temperature, using version Sly4 of the Skyrme interaction as well as two density-dependent versions of the finite-range M3Y interaction (CDM3Y$n$ and M3Y-P$n$), and versions D1S and D1N of the Gogny interaction. Although the considered effective NN interactions were proven to be quite realistic in numerous nuclear structure and/or reaction studies, they give quite different behaviors of the symmetry energy of nuclear matter at supranuclear densities that lead to the \\emph{soft} and \\emph{stiff} scenarios discussed recently in the literature. Different EOS's of the NS core and the EOS of the NS crust given by the compressible liquid drop model have been used as input of the...
Cold nuclear matter effects on the correlation between eccentricity and multiplicity
International Nuclear Information System (INIS)
Nuclear shadowing effects have been included in the Monte Carlo Glauber Model (MCGM) to study the correlation between multiplicity and the eccentricity of the geometry of the matter formed in relativistic nuclear collision. Collision of two nuclei at relativistic energies may produce a deconfined system of quarks and gluons. Assuming it gets thermalized, its subsequent evolution is determined by relativistic hydrodynamic equations together with an equation of state. Solving these equations require an initial energy density and velocity profile as inputs (in case when the net baryon number is zero). A first principle calculation for energy deposition in relativistic heavy ion collisions (RHIC) is yet to be achieved. Several models have been proposed to understand the correlation between the initial energy profile and multiplicity. Among these, one of the successful models is the IP-Glasma model based on the Color Glass Condensate approach. The Glauber model (GM) which has successfully reproduced several experimental results has predicted a knee-like structure in the variation of eccentricity with multiplicity. However, in the present work we show that the 'knee' in such correlation disappear if some of the legitimate physical effects relevant for cold nuclear matter like shadowing is included within the framework of GM
Cold Nuclear Matter Effects on J/psi and Upsilon Production at the LHC
Energy Technology Data Exchange (ETDEWEB)
Vogt, R
2009-06-23
The charmonium yields are expected to be considerably suppressed if a deconfined medium is formed in high-energy heavy-ion collisions. In addition, the bottomonium states, with the possible exception of the {Upsilon}(1S) state, are also expected to be suppressed in heavy-ion collisions. However, in proton-nucleus collisions the quarkonium production cross sections, even those of the {Upsilon}(1S), scale less than linearly with the number of binary nucleon-nucleon collisions. These 'cold nuclear matter' effects need to be accounted for before signals of the high density QCD medium can be identified in the measurements made in nucleus-nucleus collisions. We identify two cold nuclear matter effects important for midrapidity quarkonium production: 'nuclear absorption', typically characterized as a final-state effect on the produced quarkonium state and shadowing, the modification of the parton densities in nuclei relative to the nucleon, an initial-state effect. We characterize these effects and study their energy and rapidity dependence.
2010-09-09
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2010-12-01
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First measurement of nuclear recoil head-tail sense in a fiducialised WIMP dark matter detector
Battat, J B R; Ezeribe, A C; Gauvreau, J -L; Harton, J L; Lafler, R; Lee, E R; Loomba, D; Lumnah, A; Miller, E H; Mouton, F; Murphy, A StJ; Paling, S M; Phan, N S; Robinson, M; Sadler, S W; Scarff, A; Schuckman, F G; Snowden-Ifft, D P; Spooner, N J C
2016-01-01
Recent computational results suggest that directional dark matter detectors have potential to probe for WIMP dark matter particles below the neutrino floor. The DRIFT-IId detector used in this work is a leading directional WIMP search time projection chamber detector. We report the first measurements of the detection of the directional nuclear recoils in a fully fiducialised low-pressure time projection chamber. In this new operational mode, the distance between each event vertex and the readout plane is determined by the measurement of minority carriers produced by adding a small amount of oxygen to the nominal CS$_{2}$ + CF$_{4}$ target gas mixture. The CS$_2$ + CF$_4$ + O$_2$ mixture has been shown to enable background-free operation at current sensitivities. Sulfur, fluorine, and carbon recoils were generated using neutrons emitted from a $^{252}$Cf source positioned at different locations around the detector. Measurement of the relative energy loss along the recoil tracks allowed the track vector sense, ...
Effects of nuclear deformation on the form factor for direct dark matter detection
Institute of Scientific and Technical Information of China (English)
CHEN Ya-Zheng; CHEN Jun-Mou; LUO Yan-An; SHEN Hong; LI Xue-Qian
2012-01-01
For the detection of direct dark matter,in order to extract useful information about the fundamental interactions from the data,it is crucial to properly determine the nuclear form factor.The form factor for the spin-independent cross section of collisions between dark matter particles and the nucleus has been thoroughly studied by many authors.When the analysis was carried out,the nuclei were always supposed to be spherically symmetric.In this work,we investigate the effects of the deformation of nuclei from a spherical shape to an elliptical one on the form factor.Our results indicate that as long as the ellipticity is not too large,such deformation will not cause any substantial effects.In particular,when the nuclei are randomly orientated in room-temperature circumstances,one can completely neglect them.
Relativistic model for nuclear matter and atomic nuclei with momentum-dependent self-energies
Typel, S
2005-01-01
The Lagrangian density of standard relativistic mean-field (RMF) models with density-dependent meson-nucleon coupling vertices is modified by introducing couplings of the meson fields to derivative nucleon densities. As a consequence, the nucleon self energies, that describe the effective in-medium interaction, become momentum dependent. In this approach it is possible to increase the effective (Landau) mass of the nucleons, that is related to the density of states at the Fermi energy, as compared to conventional relativistic models. At the same time the relativistic effective (Dirac) mass is kept small in order to obtain a realistic strength of the spin-orbit interaction. Additionally, the empirical Schroedinger-equivalent central optical potential from Dirac phenomenology is reasonably well described. A parametrization of the model is obtained by a fit to properties of doubly magic atomic nuclei. Results for symmetric nuclear matter, neutron matter and finite nuclei are discussed.
Three nucleon forces in nuclear matter in the QCD sum rules
Drukarev, E G; Sadovnikova, V A
2016-01-01
We calculate the single-particle nucleon characteristics in symmetric nuclear matter with inclusion of the 3N interactions. The contribution of the 3N forces to the nucleon self energies are expressed in terms of the nonlocal scalar condensate (d=3) and of the configuration of the two four-quark condensates (d=6) in which two diquark operators act on two different nucleons of the matter. The most important part of the contribution of the four-quark condensate is calculated in a model-independent way. We employed a relativistic quark model of nucleon for calculation of the rest part. The density dependence of the vector and scalar nucleon self energies and of the single-particle potential energy are obtained.
Pauli quenching effects in a simple string model of quark/nuclear matter
International Nuclear Information System (INIS)
The method of thermodynamic Green's functions is applied to a nonrelativistic many-quark model system. A color-saturated confinement interaction is introduced by considering nearest-neighbor string configurations. The equation of state which accounts for the formation of three-particle bound states is derived within a ladder Hartree-Fock approximation. The temperature- and density-dependent energy shift of the intrinsic nucleonic system is calculated by considering the exchange symmetry (Pauli principle) between the quark constituents of the nucleons. The relation of this nucleonic quasiparticle energy shift to nuclear-matter data is pointed out. It is shown that beyond a critical density the nucleonic clusters are dissolved due to the Pauli quenching effects. The hadronic-to-quark-matter phase transition is considered at zero temperature
Cold nuclear matter effects on the color singlet J/psi production in d-Au collisions at RHIC
Jiang, Zefang; Feng, Shengqin; Yin, Zhongbao; Shi, Yafei; Yuan, Xianbao
2014-01-01
We use a Modified DKLMT model (called M-DKLMT model) to study the cold nuclear matter (CNM) effects on the color singlet J/psi production in dAu collisions at RHIC. The cold nuclear effect of dipole-nucleus interactions has been investigated by introducing a nuclear geometric effect function f({\\xi}) to study the nuclear geometry distribution effect in relativistic heavy-ion collisions. The dependencies of nuclear modification factors (RdA) on rapidity and centrality are studied and compared ...
Cold nuclear matter effects on the color singlet J/psi production in d-Au collisions at RHIC
Jiang, Zefang; Yin, Zhongbao; Shi, Yafei; Yuan, Xianbao
2014-01-01
We develop a Modified DKLMT model (called M-DKLMT model) to study the cold nuclear matter (CNM) effects on the color singlet J/psi production in d-Au collisions at RHIC. The cold nuclear effect has been investigated by introducing a nuclear geometric effect function f({\\xi}) and considering the nuclear geometry effect. The dependencies of nuclear modification factors (RdA) on rapidity and centrality are studied and compared to experimental data. It is found that the M-DKLMT model can well describe the experimental results at both forward- and mid-rapidity regions in collisions at RHIC.
Variational approaches to the nuclear-matter problem: A progress report
International Nuclear Information System (INIS)
The elements of state-independent Jastrow Fermi-hypermetted chain theory, of state-dependent variational theory, and of the method of correlated basis functions are surveyed. Results from application of these 'variational' approaches to popular homework potentials and to semi-realistic models of the nucleon-nucleon interaction are collected, and compared with recent results from Brueckner-Bethe theory. The crisis in nuclear-matter theory, brought on by gross discrepancies between earlier Brueckner-Bethe and variational calculations, has abated. (orig.)
Covariance analysis of finite temperature density functional theory: symmetric nuclear matter
Rios, A
2014-01-01
We study symmetric nuclear matter at finite temperature, with particular emphasis on the liquid-gas phase transition. We use a standard covariance analysis to propagate statistical uncertainties from the density functional to the thermodynamic properties. We use four functionals with known covariance matrices to obtain as wide a set of results as possible. Our findings suggest that thermodynamical properties are very well constrained by fitting data at zero temperature. The propagated statistical errors in the liquid-gas phase transition parameters are relatively small.
Spinodal instabilities in nuclear matter in a stochastic relativistic mean-field approach
International Nuclear Information System (INIS)
Spinodal instabilities and early growth of baryon density fluctuations in symmetric nuclear matter are investigated in the basis of the stochastic extension of the relativistic mean-field approach in the semiclassical approximation. Calculations are compared with the results of nonrelativistic calculations based on Skyrme-type effective interactions under similar conditions. A qualitative difference appears in the unstable response of the system: the system exhibits most unstable behavior at higher baryon densities around ρb=0.4ρ0 in the relativistic approach while most unstable behavior occurs at lower baryon densities around ρb=0.2ρ0 in the nonrelativistic calculations
Weak response of cold symmetric nuclear matter at three-body cluster level
Lovato, Alessandro; Benhar, Omar
2012-01-01
We studied the Fermi and Gamow-Teller responses of cold symmetric nuclear matter within a unified dynamical model, suitable to account for both short- and long-range correlation effects. The formalism of correlated basis functions has been used to construct two-body effective interactions and one-body effective weak operators. The inclusion of the three-body cluster term allowed for incorporating in the effective interaction a realistic model of three- nucleon forces, namely the UIX potential. Moreover, the sizable unphysical dependence of the effective weak operator is removed once the three-body cluster term is taken into account.
Exact treatment of the Pauli exclusion operator in the nuclear matter Bethe-Goldstone equation
International Nuclear Information System (INIS)
We solve the Bethe-Goldstone equation in nuclear matter for the scattering of a nucleon of a few hundred MeV. The angular momentum coupling caused by the nonspherical part of the Pauli blocking operator is treated exactly. It is found that standard approximation of angle averaging the Pauli operator is quite accurate for bulk properties of the reaction matrix even at energies as high as 300 MeV. Our result justifies one of the common approximations previously untested in the microscopic calculation of the optical model potential
Critical phenomena of nuclear matter in the extended Zimanyi-Moszkowski model
Miyazaki, K
2005-01-01
We have studied the thermodynamics of warm nuclear matter below the saturation density in the extended Zimanyi-Moszkowski model. The EOS behaves like van der Waals one and shows the liquid-gas phase transition as the other microscopic EOSs. It predicts the critical temperature T_{C}=16.36MeV that agrees well with its empirical value. We have further calculated the phase coexistence curve and obtained the critical exponents beta=0.34 and gamma=1.22, which also agree with their universal values and empirical values derived in the recent experimental efforts.
Seyyedi, S A
2015-01-01
Fusion reactions with a weakly bound projectile are studied using the double-folding model along with a repulsive interaction modifying term. Using this modified potential, including nuclear matter incompressibility effects, the fusion reaction cross sections and suppression parameters are calculated for 9Be +209Bi,208Pb,29Si and 27Al reactions. The results show that applying these effects at energies near the Coulomb barrier improves the agreement between the calculated and experimental cross sections, and modifies the mean values of the suppression parameter.
Nucleon effective mass in symmetric nuclear matter from the extended Brueckner-Hartree-Fock approach
Institute of Scientific and Technical Information of China (English)
GAN Sheng-Xin; ZUO Wei; U. Lombardo
2012-01-01
We have calculated the nucleon effective mass in symmetric nuclear matter within the framework of the Brueckner-Bethe-Goldstone (BBG) theory,which has been extended to include both the contributions from the ground-state correlation effect and the three-body force (TBF) rearrangement effect.The effective mass is predicted by including the ground-state correlation effect and the TBF rearrangement effect,and we discuss the momentum dependence and the density dependence of the effective mass.It is shown that the effect of ground state correlations plays an important role at low densities,while the TBF-induced rearrangement effect becomes predominant at high densities.
International Nuclear Information System (INIS)
We evaluate the in-medium spectral functions for pions, nucleon and isobar resonances in a self consistent and covariant manner. The calculations are based on a recently developed formulation which leads to predictions in terms of the pion-nucleon scattering phase shifts and a set of Migdal parameters describing important short range correlation effects. We do not observe any significant softening of pion modes if we insist on reasonable isobar resonance properties but predict a considerable broadening of the N(1440) and N(1520) resonances in nuclear matter. (orig.)
Jiang, Wei-Zhou; Li, Bao-An; Chen, Lie-Wen
2007-01-01
Using in-medium hadron properties according to the Brown-Rho scaling due to the chiral symmetry restoration at high densities and considering naturalness of the coupling constants, we have newly constructed several relativistic mean-field Lagrangians with chiral limits. The model parameters are adjusted such that the symmetric part of the resulting equation of state at supra-normal densities is consistent with that required by the collective flow data from high energy heavy-ion reactions, whi...
Constraining mean-field models of the nuclear matter equation of state at low densities
Voskresenskaya, M D
2012-01-01
An extension of the generalized relativistic mean-field (gRMF) model with density dependent couplings is introduced in order to describe thermodynamical properties and the composition of dense nuclear matter for astrophysical applications. Bound states of light nuclei and two-nucleon scattering correlations are considered as explicit degrees of freedom in the thermodynamical potential. They are represented by quasiparticles with medium dependent properties. The model interpolates between the correct low-density limit, the model independent virial equation of state (VEoS), and the RMF description around nuclear saturation density where clusters are dissolved. A comparison between the fugacity expansions of the VEoS and the gRMF model provides consistency relations between the quasiparticles properties, the nucleon-nucleon scattering phase shifts and the meson-nucleon couplings of the gRMF model at zero density. Relativistic effects are found to be important at temperatures that are typical in astrophysical app...
Schenke, Björn; Tribedy, Prithwish; Venugopalan, Raju
2014-11-01
The IP-Glasma model of initial conditions based on the ab initio color glass condensate framework successfully explains most of the bulk features of the global data for various systems like p+p, p+A and A+A over a wide range of energies. We employ this framework to study deformed U+U collisions, asymmetric Cu+Au collisions and the effect of deformation in Au+Au collisions at RHIC. A combined study of these heavy ion systems with varying initial geometries can provide a unique opportunity to determine the origin of different sources of fluctuations that affect global observables like multiplicity and flow. We study the sensitivity of multiplicity, eccentricity and their event-by-event distributions to the details of initial state geometry. Results are compared to a two-component MC-Glauber model implementation that includes Negative-Binomial multiplicity fluctuations. We argue that the measurements of global observables for these systems at RHIC can constrain the mechanism of multi-particle production.
Adare, A; Aidala, C; Ajitanand, N N; Akiba, Y; Akimoto, R; Al-Bataineh, H; Al-Ta'ani, H; Alexander, J; Andrews, K R; Angerami, A; Aoki, K; Apadula, N; Appelt, E; Aramaki, Y; Armendariz, R; Aschenauer, E C; Atomssa, E T; Averbeck, R; Awes, T C; Azmoun, B; Babintsev, V; Bai, M; Baksay, G; Baksay, L; Bannier, B; Barish, K N; Bassalleck, B; Basye, A T; Bathe, S; Baublis, V; Baumann, C; Bazilevsky, A; Belikov, S; Belmont, R; Ben-Benjamin, J; Bennett, R; Bhom, J H; Blau, D S; Bok, J S; Boyle, K; Brooks, M L; Broxmeyer, D; Buesching, H; Bumazhnov, V; Bunce, G; Butsyk, S; Campbell, S; Caringi, A; Castera, P; Chen, C-H; Chi, C Y; Chiu, M; Choi, I J; Choi, J B; Choudhury, R K; Christiansen, P; Chujo, T; Chung, P; Chvala, O; Cianciolo, V; Citron, Z; Cole, B A; Conesa Del Valle, Z; Connors, M; Csanád, M; Csörgő, T; Dahms, T; Dairaku, S; Danchev, I; Das, K; Datta, A; David, G; Dayananda, M K; Denisov, A; Deshpande, A; Desmond, E J; Dharmawardane, K V; Dietzsch, O; Dion, A; Donadelli, M; Drapier, O; Drees, A; Drees, K A; Durham, J M; Durum, A; Dutta, D; D'Orazio, L; Edwards, S; Efremenko, Y V; Ellinghaus, F; Engelmore, T; Enokizono, A; En'yo, H; Esumi, S; Fadem, B; Fields, D E; Finger, M; Finger, M; Fleuret, F; Fokin, S L; Fraenkel, Z; Frantz, J E; Franz, A; Frawley, A D; Fujiwara, K; Fukao, Y; Fusayasu, T; Gal, C; Garishvili, I; Glenn, A; Gong, H; Gong, X; Gonin, M; Goto, Y; Granier de Cassagnac, R; Grau, N; Greene, S V; Grim, G; Grosse Perdekamp, M; Gunji, T; Guo, L; Gustafsson, H-Å; Haggerty, J S; Hahn, K I; Hamagaki, H; Hamblen, J; Han, R; Hanks, J; Harper, C; Hashimoto, K; Haslum, E; Hayano, R; He, X; Heffner, M; Hemmick, T K; Hester, T; Hill, J C; Hohlmann, M; Hollis, R S; Holzmann, W; Homma, K; Hong, B; Horaguchi, T; Hori, Y; Hornback, D; Huang, S; Ichihara, T; Ichimiya, R; Iinuma, H; Ikeda, Y; Imai, K; Inaba, M; Iordanova, A; Isenhower, D; Ishihara, M; Issah, M; Ivanischev, D; Iwanaga, Y; Jacak, B V; Jia, J; Jiang, X; Jin, J; John, D; Johnson, B M; Jones, T; Joo, K S; Jouan, D; Jumper, D S; Kajihara, F; Kamin, J; Kaneti, S; Kang, B H; Kang, J H; Kang, J S; Kapustinsky, J; Karatsu, K; Kasai, M; Kawall, D; Kawashima, M; Kazantsev, A V; Kempel, T; Khanzadeev, A; Kijima, K M; Kikuchi, J; Kim, A; Kim, B I; Kim, D J; Kim, E-J; Kim, Y-J; Kim, Y K; Kinney, E; Kiss, A; Kistenev, E; Kleinjan, D; Kline, P; Kochenda, L; Komkov, B; Konno, M; Koster, J; Kotov, D; Král, A; Kravitz, A; Kunde, G J; Kurita, K; Kurosawa, M; Kwon, Y; Kyle, G S; Lacey, R; Lai, Y S; Lajoie, J G; Lebedev, A; Lee, D M; Lee, J; Lee, K B; Lee, K S; Lee, S H; Lee, S R; Leitch, M J; Leite, M A L; Li, X; Lichtenwalner, P; Liebing, P; Lim, S H; Linden Levy, L A; Liška, T; Liu, H; Liu, M X; Love, B; Lynch, D; Maguire, C F; Makdisi, Y I; Malik, M D; Manion, A; Manko, V I; Mannel, E; Mao, Y; Masui, H; Matathias, F; McCumber, M; McGaughey, P L; McGlinchey, D; McKinney, C; Means, N; Mendoza, M; Meredith, B; Miake, Y; Mibe, T; Mignerey, A C; Miki, K; Milov, A; Mitchell, J T; Miyachi, Y; Mohanty, A K; Moon, H J; Morino, Y; Morreale, A; Morrison, D P; Motschwiller, S; Moukhanova, T V; Murakami, T; Murata, J; Nagamiya, S; Nagle, J L; Naglis, M; Nagy, M I; Nakagawa, I; Nakamiya, Y; Nakamura, K R; Nakamura, T; Nakano, K; Nam, S; Newby, J; Nguyen, M; Nihashi, M; Nouicer, R; Nyanin, A S; Oakley, C; O'Brien, E; Oda, S X; Ogilvie, C A; Oka, M; Okada, K; Onuki, Y; Oskarsson, A; Ouchida, M; Ozawa, K; Pak, R; Pantuev, V; Papavassiliou, V; Park, B H; Park, I H; Park, S K; Park, W J; Pate, S F; Patel, L; Pei, H; Peng, J-C; Pereira, H; Peressounko, D Yu; Petti, R; Pinkenburg, C; Pisani, R P; Proissl, M; Purschke, M L; Qu, H; Rak, J; Ravinovich, I; Read, K F; Rembeczki, S; Reygers, K; Riabov, V; Riabov, Y; Richardson, E; Roach, D; Roche, G; Rolnick, S D; Rosati, M; Rosen, C A; Rosendahl, S S E; Ružička, P; Sahlmueller, B; Saito, N; Sakaguchi, T; Sakashita, K; Samsonov, V; Sano, S; Sarsour, M; Sato, T; Savastio, M; Sawada, S; Sedgwick, K; Seele, J; Seidl, R; Seto, R; Sharma, D; Shein, I; Shibata, T-A; Shigaki, K; Shim, H H; Shimomura, M; Shoji, K; Shukla, P; Sickles, A; Silva, C L; Silvermyr, D; Silvestre, C; Sim, K S; Singh, B K; Singh, C P; Singh, V; Slunečka, M; Sodre, T; Soltz, R A; Sondheim, W E; Sorensen, S P; Sourikova, I V; Stankus, P W; Stenlund, E; Stoll, S P; Sugitate, T; Sukhanov, A; Sun, J; Sziklai, J; Takagui, E M; Takahara, A; Taketani, A; Tanabe, R; Tanaka, Y; Taneja, S; Tanida, K; Tannenbaum, M J; Tarafdar, S; Taranenko, A; Tennant, E; Themann, H; Thomas, D; Thomas, T L; Togawa, M; Toia, A; Tomášek, L; Tomášek, M; Torii, H; Towell, R S; Tserruya, I; Tsuchimoto, Y; Utsunomiya, K; Vale, C; Valle, H; van Hecke, H W; Vazquez-Zambrano, E; Veicht, A; Velkovska, J; Vértesi, R; Virius, M; Vossen, A; Vrba, V; Vznuzdaev, E; Wang, X R; Watanabe, D; Watanabe, K; Watanabe, Y; Watanabe, Y S; Wei, F; Wei, R; Wessels, J; White, S N; Winter, D; Woody, C L; Wright, R M; Wysocki, M
2014-06-27
The PHENIX experiment has measured open heavy-flavor production via semileptonic decay over the transverse momentum range 1 < p(T) < 6 GeV/c at forward and backward rapidity (1.4 < |y| < 2.0) in d+Au and p + p collisions at √sNN = 200 GeV. In central d+Au collisions, relative to the yield in p + p collisions scaled by the number of binary nucleon-nucleon collisions, a suppression is observed at forward rapidity (in the d-going direction) and an enhancement at backward rapidity (in the Au-going direction). Predictions using nuclear-modified-parton-distribution functions, even with additional nuclear-p(T) broadening, cannot simultaneously reproduce the data at both rapidity ranges, which implies that these models are incomplete and suggests the possible importance of final-state interactions in the asymmetric d + Au collision system. These results can be used to probe cold-nuclear-matter effects, which may significantly affect heavy-quark production, in addition to helping constrain the magnitude of charmonia-breakup effects in nuclear matter.
Adare, A; Aidala, C; Ajitanand, N N; Akiba, Y; Akimoto, R; Al-Bataineh, H; Al-Ta'ani, H; Alexander, J; Andrews, K R; Angerami, A; Aoki, K; Apadula, N; Appelt, E; Aramaki, Y; Armendariz, R; Aschenauer, E C; Atomssa, E T; Averbeck, R; Awes, T C; Azmoun, B; Babintsev, V; Bai, M; Baksay, G; Baksay, L; Bannier, B; Barish, K N; Bassalleck, B; Basye, A T; Bathe, S; Baublis, V; Baumann, C; Bazilevsky, A; Belikov, S; Belmont, R; Ben-Benjamin, J; Bennett, R; Bhom, J H; Blau, D S; Bok, J S; Boyle, K; Brooks, M L; Broxmeyer, D; Buesching, H; Bumazhnov, V; Bunce, G; Butsyk, S; Campbell, S; Caringi, A; Castera, P; Chen, C-H; Chi, C Y; Chiu, M; Choi, I J; Choi, J B; Choudhury, R K; Christiansen, P; Chujo, T; Chung, P; Chvala, O; Cianciolo, V; Citron, Z; Cole, B A; Conesa Del Valle, Z; Connors, M; Csanád, M; Csörgő, T; Dahms, T; Dairaku, S; Danchev, I; Das, K; Datta, A; David, G; Dayananda, M K; Denisov, A; Deshpande, A; Desmond, E J; Dharmawardane, K V; Dietzsch, O; Dion, A; Donadelli, M; Drapier, O; Drees, A; Drees, K A; Durham, J M; Durum, A; Dutta, D; D'Orazio, L; Edwards, S; Efremenko, Y V; Ellinghaus, F; Engelmore, T; Enokizono, A; En'yo, H; Esumi, S; Fadem, B; Fields, D E; Finger, M; Finger, M; Fleuret, F; Fokin, S L; Fraenkel, Z; Frantz, J E; Franz, A; Frawley, A D; Fujiwara, K; Fukao, Y; Fusayasu, T; Gal, C; Garishvili, I; Glenn, A; Gong, H; Gong, X; Gonin, M; Goto, Y; Granier de Cassagnac, R; Grau, N; Greene, S V; Grim, G; Grosse Perdekamp, M; Gunji, T; Guo, L; Gustafsson, H-Å; Haggerty, J S; Hahn, K I; Hamagaki, H; Hamblen, J; Han, R; Hanks, J; Harper, C; Hashimoto, K; Haslum, E; Hayano, R; He, X; Heffner, M; Hemmick, T K; Hester, T; Hill, J C; Hohlmann, M; Hollis, R S; Holzmann, W; Homma, K; Hong, B; Horaguchi, T; Hori, Y; Hornback, D; Huang, S; Ichihara, T; Ichimiya, R; Iinuma, H; Ikeda, Y; Imai, K; Inaba, M; Iordanova, A; Isenhower, D; Ishihara, M; Issah, M; Ivanischev, D; Iwanaga, Y; Jacak, B V; Jia, J; Jiang, X; Jin, J; John, D; Johnson, B M; Jones, T; Joo, K S; Jouan, D; Jumper, D S; Kajihara, F; Kamin, J; Kaneti, S; Kang, B H; Kang, J H; Kang, J S; Kapustinsky, J; Karatsu, K; Kasai, M; Kawall, D; Kawashima, M; Kazantsev, A V; Kempel, T; Khanzadeev, A; Kijima, K M; Kikuchi, J; Kim, A; Kim, B I; Kim, D J; Kim, E-J; Kim, Y-J; Kim, Y K; Kinney, E; Kiss, A; Kistenev, E; Kleinjan, D; Kline, P; Kochenda, L; Komkov, B; Konno, M; Koster, J; Kotov, D; Král, A; Kravitz, A; Kunde, G J; Kurita, K; Kurosawa, M; Kwon, Y; Kyle, G S; Lacey, R; Lai, Y S; Lajoie, J G; Lebedev, A; Lee, D M; Lee, J; Lee, K B; Lee, K S; Lee, S H; Lee, S R; Leitch, M J; Leite, M A L; Li, X; Lichtenwalner, P; Liebing, P; Lim, S H; Linden Levy, L A; Liška, T; Liu, H; Liu, M X; Love, B; Lynch, D; Maguire, C F; Makdisi, Y I; Malik, M D; Manion, A; Manko, V I; Mannel, E; Mao, Y; Masui, H; Matathias, F; McCumber, M; McGaughey, P L; McGlinchey, D; McKinney, C; Means, N; Mendoza, M; Meredith, B; Miake, Y; Mibe, T; Mignerey, A C; Miki, K; Milov, A; Mitchell, J T; Miyachi, Y; Mohanty, A K; Moon, H J; Morino, Y; Morreale, A; Morrison, D P; Motschwiller, S; Moukhanova, T V; Murakami, T; Murata, J; Nagamiya, S; Nagle, J L; Naglis, M; Nagy, M I; Nakagawa, I; Nakamiya, Y; Nakamura, K R; Nakamura, T; Nakano, K; Nam, S; Newby, J; Nguyen, M; Nihashi, M; Nouicer, R; Nyanin, A S; Oakley, C; O'Brien, E; Oda, S X; Ogilvie, C A; Oka, M; Okada, K; Onuki, Y; Oskarsson, A; Ouchida, M; Ozawa, K; Pak, R; Pantuev, V; Papavassiliou, V; Park, B H; Park, I H; Park, S K; Park, W J; Pate, S F; Patel, L; Pei, H; Peng, J-C; Pereira, H; Peressounko, D Yu; Petti, R; Pinkenburg, C; Pisani, R P; Proissl, M; Purschke, M L; Qu, H; Rak, J; Ravinovich, I; Read, K F; Rembeczki, S; Reygers, K; Riabov, V; Riabov, Y; Richardson, E; Roach, D; Roche, G; Rolnick, S D; Rosati, M; Rosen, C A; Rosendahl, S S E; Ružička, P; Sahlmueller, B; Saito, N; Sakaguchi, T; Sakashita, K; Samsonov, V; Sano, S; Sarsour, M; Sato, T; Savastio, M; Sawada, S; Sedgwick, K; Seele, J; Seidl, R; Seto, R; Sharma, D; Shein, I; Shibata, T-A; Shigaki, K; Shim, H H; Shimomura, M; Shoji, K; Shukla, P; Sickles, A; Silva, C L; Silvermyr, D; Silvestre, C; Sim, K S; Singh, B K; Singh, C P; Singh, V; Slunečka, M; Sodre, T; Soltz, R A; Sondheim, W E; Sorensen, S P; Sourikova, I V; Stankus, P W; Stenlund, E; Stoll, S P; Sugitate, T; Sukhanov, A; Sun, J; Sziklai, J; Takagui, E M; Takahara, A; Taketani, A; Tanabe, R; Tanaka, Y; Taneja, S; Tanida, K; Tannenbaum, M J; Tarafdar, S; Taranenko, A; Tennant, E; Themann, H; Thomas, D; Thomas, T L; Togawa, M; Toia, A; Tomášek, L; Tomášek, M; Torii, H; Towell, R S; Tserruya, I; Tsuchimoto, Y; Utsunomiya, K; Vale, C; Valle, H; van Hecke, H W; Vazquez-Zambrano, E; Veicht, A; Velkovska, J; Vértesi, R; Virius, M; Vossen, A; Vrba, V; Vznuzdaev, E; Wang, X R; Watanabe, D; Watanabe, K; Watanabe, Y; Watanabe, Y S; Wei, F; Wei, R; Wessels, J; White, S N; Winter, D; Woody, C L; Wright, R M; Wysocki, M; Yamaguchi, Y L; Yamaura, K; Yang, R; Yanovich, A; Ying, J; Yokkaichi, S; Yoo, J S; You, Z; Young, G R; Younus, I; Yushmanov, I E; Zajc, W A; Zelenski, A; Zhou, S
2014-06-27
The PHENIX experiment has measured open heavy-flavor production via semileptonic decay over the transverse momentum range 1 < p(T) < 6 GeV/c at forward and backward rapidity (1.4 < |y| < 2.0) in d+Au and p + p collisions at √sNN = 200 GeV. In central d+Au collisions, relative to the yield in p + p collisions scaled by the number of binary nucleon-nucleon collisions, a suppression is observed at forward rapidity (in the d-going direction) and an enhancement at backward rapidity (in the Au-going direction). Predictions using nuclear-modified-parton-distribution functions, even with additional nuclear-p(T) broadening, cannot simultaneously reproduce the data at both rapidity ranges, which implies that these models are incomplete and suggests the possible importance of final-state interactions in the asymmetric d + Au collision system. These results can be used to probe cold-nuclear-matter effects, which may significantly affect heavy-quark production, in addition to helping constrain the magnitude of charmonia-breakup effects in nuclear matter. PMID:25014805
Spectral Methods and Propagation for the Nuclear Matter out of the Mass-shell
International Nuclear Information System (INIS)
We present a new method of calculations for nuclear matter, a system of strongly interacting fermions. Methods used up to now are based on the summation of ladder diagrams with the propagation of two particles. The resummation of an infinite series of ladder diagrams makes possible the calculations for a system of many particles strongly interacting on short distances. The method discussed in this work using in-medium Green's function's formalism and is based on the summation of diagrams with a retarded propagation of a pair of particles or a pair of holes in a ladder diagram. The sum of such ladder diagrams is the in-medium scattering matrix (the T-matrix). Self-consistency in this approach means that the fermion propagators in the T-matrix diagrams are dressed in a nontrivial self-energy. The self-energy itself is obtained from the sum of ladder diagrams. This self-consistency requires the use of full spectral functions depending on the momentum and energy of the particle. The propagation of the mass shell, i.e. the full dependence of the nucleon propagator on the energy, is a serious difficulty in numerical applications. Besides the author only two other groups presented results of such calculations in nuclear matter using simple, model nucleon-nucleon interactions. In this work we present the results of the first, and up to now the only, self-consistent T-matrix calculations for a realistic nuclear interaction at zero and finite temperature. It is one of two main achievements of this work. Attractive nuclear interactions lead to the formation of a superfluid phase at low temperatures. Cooper pairs of fermions are formed, analogously as for the electron superconductivity in a metal. The second important achievement of this work is generalization of the ladder diagram summation to the fluid phase. We construct equation which allow for a simultaneous and consistent treatment of the short range nuclear interactions, the bound state formation (cooper pairs)in T
2006-11-01
Astronomers are reporting remarkable new findings that shed light on a decade-long debate about one kind of supernovae, the explosions that mark a star's final demise: does the star die in a slow burn or with a fast bang? From their observations, the scientists find that the matter ejected by the explosion shows significant peripheral asymmetry but a nearly spherical interior, most likely implying that the explosion finally propagates at supersonic speed. These results are reported today in Science Express, the online version of the research journal Science, by Lifan Wang, Texas A&M University (USA), and colleagues Dietrich Baade and Ferdinando Patat from ESO. "Our results strongly suggest a two-stage explosion process in this type of supernova," comments Wang. "This is an important finding with potential implications in cosmology." ESO PR Photo 44/06 ESO PR Photo 44/06 Clumpy Explosion (Artist's Impression) Using observations of 17 supernovae made over more than 10 years with ESO's Very Large Telescope and the McDonald Observatory's Otto Struve Telescope, astronomers inferred the shape and structure of the debris cloud thrown out from Type Ia supernovae. Such supernovae are thought to be the result of the explosion of a small and dense star - a white dwarf - inside a binary system. As its companion continuously spills matter onto the white dwarf, the white dwarf reaches a critical mass, leading to a fatal instability and the supernova. But what sparks the initial explosion, and how the blast travels through the star have long been thorny issues. The supernovae Wang and his colleagues observed occurred in distant galaxies, and because of the vast cosmic distances could not be studied in detail using conventional imaging techniques, including interferometry. Instead, the team determined the shape of the exploding cocoons by recording the polarisation of the light from the dying stars. Polarimetry relies on the fact that light is composed of electromagnetic waves
Exploring the Quark-Gluon Content of Hadrons: From Mesons to Nuclear Matter
Energy Technology Data Exchange (ETDEWEB)
Matevosyan, Hrayr [Louisiana State Univ., Baton Rouge, LA (United States)
2007-08-01
Even though Quantum Chromodynamics (QCD) was formulated over three decades ago, it poses enormous challenges for describing the properties of hadrons from the underlying quark-gluon degrees of freedom. Moreover, the problem of describing the nuclear force from its quark-gluon origin is still open. While a direct solution of QCD to describe the hadrons and nuclear force is not possible at this time, we explore a variety of developed approaches ranging from phenomenology to first principle calculations at one or other level of approximation in linking the nuclear force to QCD. The Dyson Schwinger formulation (DSE) of coupled integral equations for the QCD Green’s functions allows a non-perturbative approach to describe hadronic properties, starting from the level of QCD n-point functions. A significant approximation in this method is the employment of a finite truncation of the system of DSEs, that might distort the physical picture. In this work we explore the effects of including a more complete truncation of the quark-gluon vertex function on the resulting solutions for the quark 2-point functions as well as the pseudoscalar and vector meson masses. The exploration showed strong indications of possibly large contributions from the explicit inclusion of the gluon 3- and 4-point functions that are omitted in this and previous analyses. We then explore the possibility of extrapolating state of the art lattice QCD calculations of nucleon form factors to the physical regime using phenomenological models of nucleon structure. Finally, we further developed the Quark Meson Coupling model for describing atomic nuclei and nuclear matter, where the quark-gluon structure of nucleons is modeled by the MIT bag model and the nucleon many body interaction is mediated by the exchange of scalar and vector mesons. This approach allows us to formulate a fully relativistic theory, which can be expanded in the nonrelativistic limit to reproduce the well known phenomenological Skyrme
Hadron resonance gas and mean-field nuclear matter for baryon number fluctuations
Fukushima, Kenji
2014-01-01
We give an estimate for the skewness and the kurtosis of the baryon number distribution in two representative models; i.e., models for a hadron resonance gas and relativistic mean-field nuclear matter. We emphasize formal similarity between these two descriptions. The hadron resonance gas leads to a deviation from the Skellam distribution if quantum statistical correlation is taken into account at high baryon density, but this effect is not strong enough to explain fluctuation data seen in the beam-energy scan at RHIC/STAR. In the calculation of mean-field nuclear matter the density correlation with the vector \\omega-field rather than the effective mass with the scalar \\sigma-field renders the kurtosis suppressed at higher baryon density so as to account for the observed behavior of the kurtosis. We finally discuss the difference between the baryon number and the proton number fluctuations from correlation effects in isospin space. Our numerical results suggest that such effects are only minor even in the cas...
Beyond the Quasi-Particle picture in Nuclear Matter calculations using Green's function techniques
Köhler, H S
2006-01-01
Widths of low-lying states in nuclei are of the order of 30 MeV. These large widths are a consequence of the strong interactions leading to a strongly correlated many body system at the typical densities of nuclear matter. Nevertheless "traditional" Brueckner calculations treat these states as quasiparticles i.e. with spectral functions of zero widths. The width is related to the imaginary part of the selfenergy and is included selfconsistently in an extension of the Brueckner theory using T-matrix and Green's function techniques. A more general formulation applicable also to non-equilibrium systems is contained in the Kadanoff-Baym (KB) equations while still maintaining the basic many-body techniques of Bruecknet theory. In the present work the two-time KB-equations are time-stepped along the imaginary time-axis to calculate the binding energy of nuclear matter as a function of density, including the spectral widths self-consistently. These zero temperature calculations are compared with quasi-particle calcu...
Coraggio, L; Itaco, N; Machleidt, R; Marcucci, L E; Sammarruca, F
2014-01-01
We compute the energy per particle of infinite symmetric nuclear matter from chiral N3LO (next-to-next-to-next-to-leading order) two-body potentials plus N2LO three-body forces. The low-energy constants of the chiral three-nucleon force that cannot be constrained by two-body observables are fitted to reproduce the triton binding energy and the 3H-3He Gamow-Teller transition matrix element. In this way, the saturation properties of nuclear matter are reproduced in a parameter-free approach. The equation of state is computed up to third order in many-body perturbation theory, with special emphasis on the role of the third-order particle-hole diagram. The dependence of these results on the cutoff scale and regulator function is studied. We find that the inclusion of three-nucleon forces consistent with the applied two-nucleon interaction leads to a reduced dependence on the choice of the regulator only for lower values of the cutoff.
$\\phi$ meson self-energy in nuclear matter from $\\phi N$ resonant interactions
Cabrera, D; Vacas, M J Vicente
2016-01-01
The $\\phi$-meson properties in cold nuclear matter are investigated by implementing resonant $\\phi N$ interactions as described in effective approaches including the unitarization of scattering amplitudes. Several $N^*$-like states are dynamically generated in these models around $2$ GeV, in the vicinity of the $\\phi N$ threshold. We find that both these states and the non-resonant part of the amplitude contribute sizably to the $\\phi$ collisional self-energy at finite nuclear density. These contributions are of a similar strength as the widely studied medium effects from the $\\bar K K$ cloud. Depending on model details (position of the resonances and strength of the coupling to $\\phi N$) we report a $\\phi$ broadening up to about $40$-$50$ MeV, to be added to the $\\phi\\to\\bar K K$ in-medium decay width, and an attractive optical potential at threshold up to about $35$ MeV at normal matter density. The $\\phi$ spectral function develops a double peak structure as a consequence of the mixing of resonance-hole mo...
Nucleon Finite Volume Effect and Nuclear Matter Properties in a Relativistic Mean-Field Theory
Institute of Scientific and Technical Information of China (English)
R. Costa; A.J. Santiago; H. Rodrigues; J. Sa Borges
2006-01-01
Effects of excluded volume of nucleons on nuclear matter are studied, and the nuclear properties that follow from different relativistic mean-field model parametrizations are compared. We show that, for all tested parametrizations,the resulting volume energy a1 and the symmetry energy J are around the acceptable values of 16 MeV and 30 MeV,and the density symmetry L is around 100 Me V. On the other hand, models that consider only linear terms lead to incompressibility K0 much higher than expected. For most parameter sets there exists a critical point (ρc,δc), where the minimum and the maximum of the equation of state are coincident and the incompressibility equals zero. This critical point depends on the excluded volume parameter r. If this parameter is larger than 0.5 fm, there is no critical point and the pure neutron matter is predicted to be bound. The maximum value for neutron star mass is 1.85M⊙, which is in agreement with the mass of the heaviest observed neutron star 4U0900-40 and corresponds to r = 0.72 fm. We also show that the light neutron star mass (1.2M⊙) is obtained for r (≌) 0.9 fm.
Covariant energy density functionals: nuclear matter constraints and global ground state properties
Afanasjev, A V
2016-01-01
The correlations between global description of the ground state properties (binding energies, charge radii) and nuclear matter properties of the state-of-the-art covariant energy density functionals have been studied. It was concluded that the strict enforcement of the constraints on the nuclear matter properties (NMP) defined in Ref.\\ \\cite{RMF-nm} will not necessary lead to the functionals with good description of the binding energies and other ground and excited state properties. In addition, it will not substantially reduce the uncertainties in the predictions of the binding energies in neutron-rich systems. It turns out that the functionals, which come close to satisfying these NMP constraints, have some problems in the description of existing data. On the other hand, these problems are either absent or much smaller in the functionals which are carefully fitted to finite nuclei but which violate some NMP constraints. This is a consequence of the fact that the properties of finite nuclei are defined not o...
The $\\pi\\rho$ Cloud Contribution to the $\\omega$ Width in Nuclear Matter
Cabrera, D
2013-01-01
The width of the $\\omega$ meson in cold nuclear matter is computed in a hadronic many-body approach, focusing on a detailed treatment of the medium modifications of intermediate $\\pi\\rho$ states. The $\\pi$ and $\\rho$ propagators are dressed by their selfenergies in nuclear matter taken from previously constrained many-body calculations. The pion selfenergy includes $Nh$ and $\\Delta h$ excitations with short-range correlations, while the $\\rho$ selfenergy incorporates the same dressing of its $2\\pi$ cloud with a full 3-momentum dependence and vertex corrections, as well as direct resonance-hole excitations; both contributions were quantitatively fit to total photo-absorption spectra and $\\pi N\\to\\rho N$ scattering. Our calculations account for in-medium decays of type $\\omega N\\to \\pi N^{(*)}, \\pi\\pi N$, and 2-body absorptions $\\omega NN \\to NN^{(*)}, \\pi NN $. This causes deviations of the in-medium $\\omega$ width from a linear behavior in density, with important contributions from spacelike $\\rho$ propagator...
Low mass dielectrons radiated off cold nuclear matter measured with HADES
Directory of Open Access Journals (Sweden)
Lorenz M.
2014-03-01
Full Text Available The High Acceptance DiElectron Spectrometer HADES [1] is installed at the Helmholtzzentrum für Schwerionenforschung (GSI accelerator facility in Darmstadt. It investigates dielectron emission and strangeness production in the 1-3 AGeV regime. A recent experiment series focusses on medium-modifications of light vector mesons in cold nuclear matter. In two runs, p+p and p+Nb reactions were investigated at 3.5 GeV beam energy; about 9·109 events have been registered. In contrast to other experiments the high acceptance of the HADES allows for a detailed analysis of electron pairs with low momenta relative to nuclear matter, where modifications of the spectral functions of vector mesons are predicted to be most prominent. Comparing these low momentum electron pairs to the reference measurement in the elementary p+p reaction, we find in fact a strong modification of the spectral distribution in the whole vector meson region.
Mass predictions of atomic nuclei in the infinite nuclear matter model
Nayak, R. C.; Satpathy, L.
2012-07-01
We present here the mass excesses, binding energies, one- and two-neutron, one- and two-proton and α-particle separation energies of 6727 nuclei in the ranges 4≤Z≤120 and 8≤A≤303 calculated in the infinite nuclear matter model. Compared to our predictions of 1999 mass table, the present ones are obtained using larger data base of 2003 mass table of Wapstra and Audi and resorting to higher accuracy in the solutions of the η-differential equations of the INM model. The local energy η's supposed to carry signature of the characteristic properties of nuclei are found to possess the predictive capability. In fact η-systematics reveal new magic numbers in the drip-line regions giving rise to new islands of stability supported by relativistic mean field theoretic calculations. This is a manifestation of a new phenomenon where shell-effect overcomes the instability due to repulsive components of the nucleon-nucleon force broadening the stability peninsula. The two-neutron separation energy-systematics derived from the present mass predictions reveal a general new feature for the existence of islands of inversion in the exotic neutron-rich regions of nuclear landscape, apart from supporting the presently known islands around 31Na and 62Ti. The five global parameters representing the properties of infinite nuclear matter, the surface, the Coulomb and the pairing terms are retained as per our 1999 mass table. The root-mean-square deviation of the present mass-fit to 2198 known masses is 342 keV, while the mean deviation is 1.3 keV, reminiscent of no left-over systematic effects. This is a substantive improvement over our 1999 mass table having rms deviation of 401 keV and mean deviation of 9 keV for 1884 data nuclei.
BEC-BCS Crossover and the Liquid-Gas Phase Transition in Hot and Dense Nuclear Matter
Jin, Meng; Schuck, Peter
2010-01-01
The effect of nucleon-nucleon correlations in symmetric nuclear matter at finite temperature is studied beyond BCS theory. Starting from a Hartree-Fock description of nuclear matter with the Gogny effective interaction, we add correlations corresponding to the formation of preformed pairs and scattering states above the superfluid critical temperature within the in-medium T-matrix approach, which is analogous to the Nozieres-Schmitt-Rink theory. We calculate the critical temperature for a BEC superfluid of deuterons, of a BCS superfluid of nucleons, and in the crossover between these limits. The effect of the correlations on thermodynamic properties (equation of state, energy, entropy) and the liquid-gas phase transition is discussed. Our results show that nucleon-nucleon correlations beyond BCS play an important role for the properties of nuclear matter, especially in the low-density region.
R&D Status of Nuclear Emulsion For Directional Dark Matter Search
Naka, T; Nakamura, M; Sato, O; Nakano, T; Asada, T; Tawara, Y; Suzuki, Y
2011-01-01
In this study, we are doing R&D for directional dark matter search with nuclear emulsion. First of all, higher resolution nuclear emulsion with fine silver halide crystals was developed in the production facility of emulsion at Nagoya university, and we confirmed that it can detect the expected nuclear recoil tracks. The readout of submicron tracks was required the new technology. We developed the expansion technique, and could readout the signal by shape analysis with optical microscopy. The two dimensional angular resolution is 36 degrees at the original track length of range from 150nm to 200nm with optical microscopy. Finally we demonstrated by using recoiled nuclei induced by 14.8MeV neutron, and confirmed the technique.Moreover, we developed the X-ray microscope system with SPring-8 as final check with higher resolution of selected candidate tracks with optical microscopy. The angular resolution was improved from 31degrees with optical microscopy to 17degrees with X-ray microscopy at the track lengt...
Computational methods for the nuclear and neutron matter problems. Progress report
International Nuclear Information System (INIS)
Progress on the development of Monte Carlo methods for the treatment of extensive nuclear and neutron matter and of finite nuclei is reported. Appropriate modifications in the Monte Carlo formalism were made and carried through for the V4 potential; the previous method was satisfactory for V3, and the latter calculations have been completed. Significant progress was made in the development of the Green's function Monte Carlo method for fermion systems. It proved useful to study a model nuclear few-body problem, in particular, a kind of three-neutron problem. This work proved successful in that a stable Monte Carlo algorithm was developed. It gave correct results for energy and wave function for a soluble (separable) test problem and reasonable results (confirmed by variational computations) for a system interacting by pairwise phenomenological potentials. A stable GFMC algorithm for many-fermion systems has not been implemented, but ancillary studies on 3He have advanced considerably. In particular, new methods for finding upper bounds have been devised in which Green's function methods are used. These have particular application to nuclear problems. Lower values of the upper bounds were found for 3He. 20 tables
Many-body forces, isospin asymmetry and dense hyperonic matter
Gomes, R O; Schramm, S; Vascconcellos, C A Z
2015-01-01
The equation of state (EoS) of asymmetric nuclear matter at high densities is a key topic for the description of matter inside neutron stars. The determination of the properties of asymmetric nuclear matter, such as the symmetry energy ($a_{sym}$) and the slope of the symmetry energy ($L_0$) at saturation density, has been exaustively studied in order to better constrain the nuclear matter EoS. However, differently from symmetric matter properties that are reasonably constrained, the symmetry energy and its slope still large uncertainties in their experimental values. Regarding this subject, some studies point towards small values of the slope of the symmetry energy, while others suggest rather higher values. Such a lack of agreement raised a certain debate in the scientific community. In this paper, we aim to analyse the role of these properties on the behavior of asymmetric hyperonic matter. Using the formalism presented in Ref. (R.O. Gomes et al 2014}, which considers many-body forces contributions in the ...
International Nuclear Information System (INIS)
The nuclear symmetry energy Esym(ρ) is the most uncertain part of the Equation of State (EOS) of dense neutron-rich nuclear matter. In this talk, we discuss the underlying physics responsible for the uncertain Esym(ρ) especially at supra-saturation densities, the circumstantial evidence for a super-soft Esym(ρ) from analyzing π-/π+ ratio in relativistic heavy-ion collisions and its impacts on astrophysics and cosmology.
Effective mass of a. lambda. -particle in nuclear matter and OBE. lambda. -n interactions
Energy Technology Data Exchange (ETDEWEB)
Bando, H. (Fukui Univ. (Japan). Faculty of Engineering); Nagata, S.
1982-02-01
The effective mass of a lambda particle (M sub( lambda )*) in nuclear matter is investigated within the framework of the lowest-order Brueckner theory by employing the Nijmegen OBE lambda -N interaction model D and F. The non-locality mass (M tilde sub( lamda )) and the energy mass (anti M sub( lambda )) are evaluated and discussed in the light of the characteristics of the two models. In comparison with the model D, the model F yields smaller anti M sub( lambda ) and larger anti M sub( lamb da ) reflecting the stronger Majorana exchange force and the stronger lambda N- sigma N coupling tensor force. Final results of M sub( lambda )*/M sub( lambda ) are 0.85 for D and 0.79 for F. In view of the effective lambda mass inferred from observed properties of the single particle potential for lambda , the model D interaction seems to be more adequate.
Onset transition to cold nuclear matter from lattice QCD with heavy quarks.
Fromm, M; Langelage, J; Lottini, S; Neuman, M; Philipsen, O
2013-03-22
Lattice QCD at finite density suffers from a severe sign problem, which has so far prohibited simulations of the cold and dense regime. Here we study the onset of nuclear matter employing a three-dimensional effective theory derived by combined strong coupling and hopping expansions, which is valid for heavy but dynamical quarks and has a mild sign problem only. Its numerical evaluations agree between a standard Metropolis and complex Langevin algorithm, where the latter is free of the sign problem. Our continuum extrapolated data approach a first order phase transition at μ(B) ≈ m(B) as the temperature approaches zero. An excellent description of the data is achieved by an analytic solution in the strong coupling limit.
What can HELIOS tell us on phase transition of nuclear matter?
International Nuclear Information System (INIS)
Transverse energy (E/sub t/) distributions and P/sub t/ spectra of negative particles and photons measured by the HELIOS experiment in 200 GeVN and 60 GeVN oxygen-nucleus reactions are presented. The E/sub t/ distributions are compared to a geometrical parametrization and a Montereverse arrowCarlo calculation, particle spectra to the proton-nucleus reaction case. The comparisons show that yet the results can be understood without assuming quark-gluon plasma formation. A discussion is made based on these comparisons together with an estimate of the energy density of the reaction, attempting to know how close we are to the detection of a phase transition of nuclear matter. 21 refs., 15 figs
Nandi, Rana
2016-01-01
We study the effect of isospin-dependent nuclear forces on the pasta phase in the inner crust of neutron stars. To this end we model the crust within the framework of quantum molecular dynamics (QMD). For maximizing the numerical performance, the newly developed code has been implemented on GPU processors. As a first application of the crust studies we investigate the dependence of the particular pasta phases on the slope of the symmetry energy slope L. To isolate the effect of different values of L, we adopt an established QMD Hamiltonian and extend it to include non-linear terms in the isospin-dependent interaction. The strengths of the isospin-dependent forces are used to adjust the asymmetry energy and slope of the matter. Our results indicate that in contrast to earlier studies the phase diagram of the pasta phase is not very sensitive to the value of L.
Toward the Limits of Matter: Ultra-relativistic nuclear collisions at CERN
Schukraft, Jurgen
2015-01-01
Strongly interacting matter as described by the thermodynamics of QCD undergoes a phase transition, from a low temperature hadronic medium to a high temperature quark-gluon plasma state. In the early universe this transition occurred during the early microsecond era. It can be investigated in the laboratory, in collisions of nuclei at relativistic energy, which create "fireballs" of sufficient energy density to cross the QCD Phase boundary. We describe 3 decades of work at CERN, devoted to the study of the QCD plasma and the phase transition. From modest beginnings at the SPS, ultra-relativistic heavy ion physics has evolved today into a central pillar of contemporary nuclear physics and forms a significant part of the LHC program.
The effect of hyperon-meson coupling in infinite nuclear matter
International Nuclear Information System (INIS)
In this work, we provide the relativistic mean field investigation of the neutron star properties by using various hyperon-meson coupling to the recently developed G2 force parameter. It is to be noted that the model used here for the study of the EoS of the hyper-nuclear matter is the effective Lagrangian (E-RMF), the extension of the standard relativistic mean field (RMF) model. From the Lagrangian, we derive the equation of motion for σ, ω and ρ-mesons fields and solve it in the mean field approximation self consistently. Further, we derive the energy and pressure density along with all meson field equations analytically by self-consistent numerical iterative methods
Measurements of hadron mean free path for the particle-producing collisions in nuclear matter
Strugalski, Z.
1985-01-01
It is not obvious a priority that the cross-section for a process in hadron collisions with free nucleons is the same as that for the process in hadron collisions with nucleons inside a target nucleus. The question arises: what is the cross-section for a process in a hadron collision with nucleon on inside the atomic nucleus. The answer to it must be found in experiments. The mean free path for particle-producing collisions of pions in nuclear matter is determined experimentally using pion-xenon nucleus collisions at 3.5 GeV/c momentum. Relation between the mean free path in question lambda sub in nucleons fm squared and the cross-section in units of fm squared/nucleon for collisions of the hadron with free nucleon is: lambda sub i = k/cross section sub i, where k = 3.00 plus or minus 0.26.
Squeeze-out of nuclear matter as a function of projectile energy and mass
Gutbrod, H. H.; Kampert, K. H.; Kolb, B.; Poskanzer, A. M.; Ritter, H. G.; Schicker, R.; Schmidt, H. R.
1990-08-01
Squeeze-out, a component of the collective flow of nuclear matter, is the preferential emission of particles out of the reaction plane. Using the sphericity method the out-of-plane/in-plane ratio of the kinetic energy flow has been analyzed as a function of multiplicity and beam energy for Ca+Ca, Nb+Nb, and Au+Au collisions measured with the Plastic Ball detector at the Bevalac. Also, azimuthal distribution of the particles around the flow axis are presented together with the extracted out-of-plane/in-plane ratios. Finally, the rapidity dependence of the out-of-plane/in-plane ratio has been investigated with a new method using the transverse momentum components of the particles.
Off-shell effects in nuclear matter from an EFT point of view
International Nuclear Information System (INIS)
Effective field theory requires all observables to be independent of the representation used for the quantum field operators. Off-shell parts of the in-medium vertex functions depend on the partucular representation so that off-shell properties of the interactions should not lead to any observable effects. We analyse this issue in the context of many-body approaches to nuclear matter, where it should be possible to shift into three-body force the contributions from purely off-shell two-body interactions. We show that none of the commonly used truncations of the two-body scattering amplitude such as the ladder, Brueckner-Hartree-Fock or parquet approximations respect this requirement
Phase diagram of dilute nuclear matter: Unconventional pairing and the BCS-BEC crossover
International Nuclear Information System (INIS)
We report on a comprehensive study of the phase structure of cold, dilute nuclear matter featuring a 3S1-3D1 condensate at non-zero isospin asymmetry, within wide ranges of temperatures and densities. We find a rich phase diagram comprising three superfluid phases, namely a LOFF phase, the ordinary BCS phase, and a heterogeneous, phase-separated BCS phase, with associated crossovers from the latter two phases to a homogeneous or phase-separated Bose-Einstein condensate of deuterons. The phase diagram contains two tri-critical points (one a Lifshitz point), which may degenerate into a single tetra-critical point for some degree of isospin asymmetry.
Competition between fermions and bosons in nuclear matter at low densities and finite temperatures
Mabiala, J; Bonasera, A; Kohley, Z; Yennello, S J
2016-01-01
We derive the free energy for fermions and bosons from fragmentation data. Inspired by the symmetry and pairing energy of the Weizsacker mass formula we obtain the free energy of fermions (nucleons) and bosons (alphas and deuterons) using Landau's free energy approach. We confirm previously obtained results for fermions and show that the free energy for alpha particles is negative and very close to the free energy for ideal Bose gases. Deuterons behave more similarly to fermions (positive free energy) rather than bosons. This is due to their low binding energy, which makes them very 'fragile', i.e., easily formed and destroyed. We show that the {\\alpha}-particle fraction is dominant at all temperatures and densities explored in this work. This is consistent with their negative free energy, which favors clusterization of nuclear matter into {\\alpha}-particles at subsaturation densities and finite temperatures. The role of finite open systems and Coulomb repulsion is addressed.
Microscopic Three-Body Force Effect on Nucleon-Nucleon Cross Sections in Symmetric Nuclear Matter
Institute of Scientific and Technical Information of China (English)
ZHANG Hong-Fei; ZUO Wei; Lombardo Umberto; LI Zeng-Hua; LI Jun-Qing
2008-01-01
We provide a microscopic calculation of neutron-proton and proton-proton cross sections in symmetric nuclear matter at various densities, using the Brueckner-Hartree-Fock approximation scheme with the Argonne V14 potential including the contribution of microscopic three-body force. We investigate separately the effects of three-body force on the effective mass and on the scattering amplitude. In the present calculation, the rearrangement contribution of three-body force is considered, which will reduce the neutron and proton effective mass, and depress the amplitude of cross section. The effect of three body force is shown to be repulsive, especially in high densities and large momenta, which will suppress the cross section markedly.
Low-energy pions in nuclear matter and 2pi photoproduction within a BUU transport model
Buss, O; Mosel, U; Mühlich, P; Alvarez-Ruso, Luis; Buss, Oliver; Mosel, Ulrich; Muehlich, Pascal
2006-01-01
A description of low-energy scattering of pions and nuclei within a BUU transport model is presented. Implementing different scenarios of medium modifications, the mean free path of pions in nuclear matter at low momenta and pion absorption reactions on nuclei have been studied and compared to data and to results obtained via quantum mechanical scattering theory. We show that even in a regime of a long pionic wave length the semi-classical transport model is still a reliable framework for pion kinetic energies greater than ~20-30 MeV. Results are presented on pion-absorption cross sections in the regime of 10 MeV < E(kin) < 130 MeV and on photon-induced double-pion production at incident beam energies of 400-500 MeV.
Low-energy pions in nuclear matter and pi pi photoproduction within a BUU transport model
Buss, O; Mühlich, P; Mosel, U; Shyam, R; Buss, Oliver; Alvarez-Ruso, Luis; Muehlich, Pascal; Mosel, Ulrich; Shyam, Radhey
2006-01-01
In the present paper we investigate a method to describe low-energy scattering events of pions and nuclei within a Boltzmann-Uehling-Uhlenbeck (BUU) transport model. Implementing different scenarios of medium modifications, we studied the mean free path of pions in nuclear matter at low momenta and compared pion absorption simulations to data. Pursuing these studies we have shown, that also in a regime of a long pionic wave length the semi-classical BUU model still generates reasonable results. We present results on pi-induced events in the regime of 10 MeV < Tkin < 130 MeV and photo-induced pi pi production at incident beam energies of 400-460 MeV.
Moghrabi, Kassem
2016-01-01
We present the explicit form of the next-to-next-to-leading order (N$^2$LO) Skyrme interaction in momentum space by including the fourth-order gradient potentials to the standard Skyrme interaction. With the N$^2$LO Skyrme interaction, we evaluate the second-order corrections to the nuclear bulk quantities of nuclear matter: equation of state (EoS) of isospin symmetric and pure neutron matter, density-dependent in-medium effective nucleon mass, isospin-asymmetry energy, pressure and incompressibility. These second-order contributions are ultraviolet (UV) divergent due to the zero range character of the interaction and renormalized using the techniques of dimensional regularization (DR) with the minimal subtraction scheme (MS). We adjust the 18 parameters of the interaction by performing a global fit to the nuclear bulk quantities. Besides the too strong dependence $k_F^{12}$ of several second-order corrections, a very good reproduction of a realistic nuclear matter saturation curve with all the nuclear bulk q...
Measurement of Nuclear Recoils in the CDMS II Dark Matter Search
Energy Technology Data Exchange (ETDEWEB)
Fallows, Scott Mathew [Univ. of Minnesota, Minneapolis, MN (United States)
2014-12-01
The Cryogenic Dark Matter Search (CDMS) experiment is designed to directly detect elastic scatters of weakly-interacting massive dark matter particles (WIMPs), on target nuclei in semiconductor crystals composed of Si and Ge. These scatters would occur very rarely, in an overwhelming background composed primarily of electron recoils from photons and electrons, as well as a smaller but non-negligible background of WIMP-like nuclear recoils from neutrons. The CDMS II generation of detectors simultaneously measure ionization and athermal phonon signals from each scatter, allowing discrimination against virtually all electron recoils in the detector bulk. Pulse-shape timing analysis allows discrimination against nearly all remaining electron recoils taking place near detector surfaces. Along with carefully limited neutron backgrounds, this experimental program allowed for \\background- free" operation of CDMS II at Soudan, with less than one background event expected in each WIMP-search analysis. As a result, exclusionary upper-limits on WIMP-nucleon interaction cross section were placed over a wide range of candidate WIMP masses, ruling out large new regions of parameter space.
Study of hot and dense nuclear matter in effective QCD model
Islam, Chowdhury Aminul
2016-01-01
In this thesis we use various effective QCD models to investigate hot and dense nuclear matter created in heavy ion collisions. To characterize such matter, we mainly exploit correlation functions and some of the associated spectral properties. We explore the vector meson current-current correlation function with and without the influence of vector interaction in Nambu\\textendash Jona-Lasinio (NJL) model and also in its Polyakov loop extended version (PNJL). As a spectral property we have computed the dilepton rate which is found to be enhanced in strongly interacting QGP (sQGP) as compared to the Born rate in a weakly coupled QGP. We further consider the idea of entanglement between the chiral and confinement dynamics through the entangled PNJL (EPNJL) model and re-explore the vector spectral function and the spectral property such as the dilepton production rate studied in our earlier effort. Because of the strong entanglement, the coupling strengths run with the temperature and chemical potential. The impl...
Tan, Ngo Hai; Khoa, Dao T; Margueron, Jerome
2016-01-01
A consistent Hartree-Fock study of the equation of state (EOS) of asymmetric nuclear matter at finite temperature has been performed using realistic choices of the effective, density dependent nucleon-nucleon (NN) interaction, which were successfully used in different nuclear structure and reaction studies. Given the importance of the nuclear symmetry energy in the neutron star formation, EOS's associated with different behaviors of the symmetry energy were used to study hot asymmetric nuclear matter. The slope of the symmetry energy and nucleon effective mass with increasing baryon density was found to affect the thermal properties of nuclear matter significantly. Different density dependent NN interactions were further used to study the EOS of hot protoneutron star (PNS) matter of the $npe\\mu\
Enthalpic and entropic phase transitions in high energy density nuclear matter
Iosilevskiy, Igor
2014-01-01
Features of Gas-Liquid (GL) and Quark-Hadron (QH) phase transitions (PT) in dense nuclear matter are under discussion in comparison with their terrestrial counterparts, e.g. so-called "plasma" PT in shock-compressed hydrogen, nitrogen, xenon etc. Both, GLPT and QHPT, when being represented in widely accepted $T - \\mu$ diagram, are often considered as similar, i.e. amenable to one-to-one mapping by simple scaling. It is argued that this impression is illusive and that GLPT and QHPT belong to different classes: namely, GLPT is typical \\emph{enthalpic} (VdW-like) PT while QHPT ("deconfinement-driven") is typical \\emph{entropic} PT like hypothetical ionization- and dissociation-driven phase transitions in hot and dense hydrogen, nitrogen etc. of megabar pressure range. Newly introduced terms "enthalpic" and "entropic" PT, are defined and clarified in their illustrative comparison successively from $T - \\mu$ to $P - T$ and $P - V$ phase diagrams for GLPT and QHPT from one side (dense nuclear plasma) vs. GLPT and "...
Van der Waals interactions in hadron resonance gas: From nuclear matter to lattice QCD
Vovchenko, Volodymyr; Stoecker, Horst
2016-01-01
An extension of the ideal non-interacting hadron resonance gas (HRG) model is constructed which includes the attractive and repulsive van der Waals (VDW) interactions between baryons. This VDW-HRG model yields the nuclear liquid-gas transition at low temperatures and high baryon densities. The VDW parameters $a$ and $b$ are fixed by the ground state properties of nuclear matter, and the temperature dependence of various thermodynamic observables at zero chemical potential are calculated within VDW-HRG model. Compared to the ideal non-interacting HRG, the inclusion of VDW interactions between baryons leads to a qualitatively different behavior of 2nd and higher moments of fluctuations of conserved charges, in particular in the so-called crossover region $T \\sim 140 \\div 190$ MeV. For many observables this behavior resembles closely the results obtained from lattice QCD simulations. These results imply that VDW interactions play a crucial role in thermodynamics of hadron gas. Thus, the commonly performed compar...
The equation of state of nuclear matter with consideration of clusters and the Pauli-blocking effect
International Nuclear Information System (INIS)
The equation of state of nuclear matter is studied under the ladder-HF approximation with a properly chosen perturbation method to take the effects of clustering and Pauli blocking into account. Our calculated results are compared with many experimental data. (author)
The effect of three-body cluster energy on LOCV calculation for hot nuclear and neutron matter
International Nuclear Information System (INIS)
The two-body correlation functions, obtained in a lowest-order constrained variational calculation for hot nuclear and neutron matter, with the Reid potential and the explicit inclusion of Δ(1234), are state averaged and used to calculate the three-body cluster energy. The three-body cluster energy is found to vary between about 1 and 2 MeV through and beyond twice the nuclear-matter saturation density for temperatures between 5 and 20 MeV. However, the inclusion of a three-body cluster reduces the nuclear-matter flashing and critical temperatures. A critical temperature of 15.8 MeV and a critical exponent of 0.35 is found. The results of entropy calculations are in good agreement with experimental prediction and other theoretical results. Finally it is shown that by allowing an explicit Δ(1234) degree of freedom through the Reid potential up to and including the three-body clusters, the lowest-constrained variational calculation yields other nuclear- and neutron-matter properties close to the available semi-empirical and experimental data at zero and finite temperatures. (author)
INFLUENCE OF THE DELTA-DELTA-MESON COUPLING ON NUCLEON AND DELTA PROPERTIES IN NUCLEAR-MATTER
DEJONG, F; MALFLIET, R
1994-01-01
We introduce a scalar and a vector DELTADELTA-meson vertex in the relativistic Dirac-Brueckner model for nuclear matter and investigate the consequences. We find small effects on the effective nucleon properties. The effects in the DELTA sector are more profound, although the DELTA is still effectiv
FROM NUCLEAR-MATTER TO FINITE NUCLEI .1. PARAMETRIZATION OF THE DIRAC-BRUECKNER G-MATRIX
BOERSMA, HF; MALFLIET, R
1994-01-01
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, w
Density Dependence of Nuclear Symmetry Energy
Behera, B; Tripathy, S K
2016-01-01
High density behaviour of nuclear symmetry energy is studied on the basis of a stiffest density dependence of asymmetric contribution to energy per nucleon in charge neutral $n+p+e+\\mu$ matter under beta equilibrium. The density dependence of nuclear symmetry energy obtained in this way is neither very stiff nor soft at high densities and is found to be in conformity with recent observations of neutron stars
International Nuclear Information System (INIS)
The study of CP violation in beauty decay is one of the key challenges facing high energy physics. Much work has not yielded a definitive answer how this study might best be performed. However, one clear conclusion is that new accelerator facilities are needed. Proposals include experiments at asymmetric electron-positron colliders and in fixed-target and collider modes at LHC and SSC. Fixed-target and collider experiments at existing accelerators, while they might succeed in a first observation of the effect, will not be adequate to study it thoroughly. Giomataris has emphasized the potential of a new approach to the study of beauty CP violation: the asymmetric proton collider. Such a collider might be realized by the construction of a small storage ring intersecting an existing or soon-to-exist large synchrotron, or by arranging collisions between a large synchrotron and its injector. An experiment at such a collider can combine the advantages of fixed-target-like spectrometer geometry, facilitating triggering, particle identification and the instrumentation of a large acceptance, while the increased √s can provide a factor > 100 increase in beauty-production cross section compared to Tevatron or HERA fixed-target. Beams crossing at a non-zero angle can provide a small interaction region, permitting a first-level decay-vertex trigger to be implemented. To achieve large √s with a large Lorentz boost and high luminosity, the most favorable venue is the high-energy booster (HEB) at the SSC Laboratory, though the CERN SPS and Fermilab Tevatron are also worth considering
Model nuclear matter calculations with a new fermion lowest order constrained variational method
International Nuclear Information System (INIS)
A method of lowest order constrained variation for calculating the ground-state energy of dense systems, advanced previously by the present authors and shown to give excellent agreement for the Bethe homework problem is extended to deal with fermions. Using one state-independent correlation function in the new formalism, results with four different potentials that model various aspects of the real NN force are shown to be in excellent agreement with the other results available from various higher-order approximations, for densities up to and beyond nuclear matter density. The agreement is clearly superior to that obtained with any other lowest order approximation. When state dependence is introduced into the two-body correlation function in the new method, a considerable lowering of the energy is found in each case. It is suggested that this is a real effect which would be replicated in the other higher-order approximations, were they also extended to deal with state-dependent correlations. (Auth.)
ON THE FATE OF THE MATTER REINSERTED WITHIN YOUNG NUCLEAR STELLAR CLUSTERS
Energy Technology Data Exchange (ETDEWEB)
Hueyotl-Zahuantitla, Filiberto; Palous, Jan; Wuensch, Richard [Astronomical Institute, Academy of Sciences of the Czech Republic, Bocni II 1401, 141 31 Prague (Czech Republic); Tenorio-Tagle, Guillermo; Silich, Sergiy, E-mail: filibert@asu.cas.cz [Instituto Nacional de Astrofisica Optica y Electronica, AP 51, 72000 Puebla (Mexico)
2013-04-01
This paper presents a hydrodynamical model describing the evolution of the gas reinserted by stars within a rotating young nuclear star cluster (NSC). We explicitly consider the impact of the stellar component on the flow by means of a uniform insertion of mass and energy within the stellar cluster. The model includes the gravity force of the stellar component and a central supermassive black hole (SMBH), and accounts for the heating from the central source of radiation and the radiative cooling of the thermalized gas. By using a set of parameters typical for NSCs and SMBHs in Seyfert galaxies, our simulations show that a filamentary/clumpy structure is formed in the inner part of the cluster. This 'torus' is Compton-thick and covers a large fraction of the sky (as seen from the SMBH). In the outer parts of the cluster a powerful wind is produced that inhibits the infall of matter from larger scales and thus the NSC-SMBH interplay occurs in isolation.
Entropic and enthalpic phase transitions in high energy density nuclear matter
Iosilevskiy, Igor
2015-01-01
Features of Gas-Liquid (GL) and Quark-Hadron (QH) phase transitions (PT) in dense nuclear matter are under discussion in comparison with their terrestrial counterparts, e.g. so-called "plasma" PT in shock-compressed hydrogen, nitrogen etc. Both, GLPT and QHPT, when being represented in widely accepted temperature - baryonic chemical potential plane, are often considered as similar, i.e. amenable to one-to-one mapping by simple scaling. It is argued that this impression is illusive and that GLPT and QHPT belong to different classes: GLPT is typical enthalpic PT (Van-der-Waals-like) while QHPT ("deconfinement-driven") is typical entropic PT. Subdivision of 1st-order fluid-fluid phase transitions into enthalpy- and entropy-driven subclasses was proposed previously [arXiv:1403.8053]. Properties of enthalpic and entropic PTs differ significantly. Entropic PTs are always internal parts of more general and extended thermodynamic anomalies - domains with abnormal (negative) sign for the set of (usually positive) seco...
Low-density homogeneous symmetric nuclear matter: Disclosing dinucleons in coexisting phases
Energy Technology Data Exchange (ETDEWEB)
Arellano, Hugo F. [University of Chile, Department of Physics, Santiago (Chile); DAM, CEA, Arpajon (France); Delaroche, Jean-Paul [DAM, CEA, Arpajon (France)
2015-01-01
The effect of in-medium dinucleon bound states on self-consistent single-particle fields in Brueckner, Bethe and Goldstone theory is investigated in symmetric nuclear matter at zero temperature. To this end, dinucleon bound state occurences in the {sup 1}S{sub 0} and {sup 3}SD{sub 1} channels are explicitly accounted for -within the continuous choice for the auxiliary fields- while imposing self-consistency in Brueckner-Hartree-Fock approximation calculations. Searches are carried out at Fermi momenta in the range 0 < k{sub F} ≤ 1.75 fm{sup -1}, using the Argonne v{sub 18} bare nucleon-nucleon potential without resorting to the effective-mass approximation. As a result, two distinct solutions meeting the self-consistency requirement are found with overlapping domains in the interval 0.130 fm{sup -1} ≤ k{sub F} ≤ 0.285 fm{sup -1}, corresponding to mass densities between 10{sup 11.4} and 10{sup 12.4} g cm{sup -3}. Effective masses as high as three times the nucleon mass are found in the coexistence domain. The emergence of superfluidity in relationship with BCS pairing gap solutions is discussed. (orig.)
On the fate of the matter reinserted within young nuclear stellar clusters
Hueyotl-Zahuantitla, Filiberto; Wunsch, Richard; Tenorio-Tagle, Guillermo; Silich, Sergiy
2013-01-01
This paper presents a hydrodynamical model describing the evolution of the gas reinserted by stars within a rotating young nuclear star cluster (NSC). We explicitly consider the impact of the stellar component to the flow by means of a uniform insertion of mass and energy within the stellar cluster. The model includes the gravity force of the stellar component and a central supermassive black hole (SMBH), and accounts for the heating from the central source of radiation and the radiative cooling of the thermalized gas. By using a set of parameters typical for NSCs and SMBHs in Seyfert galaxies our simulations show that a filamentary/clumpy structure is formed in the inner part of the cluster. This "torus" is Compton thick and covers a large fraction of the sky (as seen from the SMBH). In the outer parts of the cluster a powerful wind is produced, that inhibits the infall of matter from larger scales and thus the NSC-SMBH interplay occurs in isolation.
Cold nuclear matter effects and a modified form of the proximity approach
Gharaei, Reza
2016-01-01
The influence of the cold nuclear matter effects on the Coulomb barriers and also on the fusion cross sections of 47 fusion reactions are systematically investigated within the framework of the proximity formalism. For this purpose, I modify the original version of this formalism (Prox. 77) using a new analytical form of the universal function which is formulated based on the double-folding model with three density-dependent versions of the M3Y-type interactions, namely DDM3Y1, CDM3Y3 and BDM3Y1. It is found that when the Prox. 77 potential is accompanied by each of the formulated universal functions, the agreement between the theoretical and experimental data of the barrier height and also the fusion cross section increase for our selected fusion systems. The present study also provides appropriate conditions to explore theoretically the variation effects of the NM incompressibility constant $K$ on the calculated results caused by the Prox. 77 model. It is shown that the accuracy of this potential model for ...
Mass Predictions of Atomic Nuclei in the Infinite Nuclear Matter Model
Nayak, R C
2012-01-01
We present here the mass excesses, binding energies, one- and two- neutron, one and two- proton and \\alpha-particle separation energies of 6727 nuclei in the ranges 4 \\leq Z \\leq 120 and 8 \\leq A \\leq 303 calculated in the infinite nuclear matter model. Compared to our predictions of 1999 mass table, the present ones are obtained using larger data base of 2003 mass table of Wapstra and Audi and resorting to higher accuracy in the solutions of the \\eta-differential equations of the INM model. The local energy \\eta's supposed to carry signature of the characteristic properties of nuclei are found to possess the predictive capability. In fact \\eta-systematics reveal new magic numbers in the drip-line regions giving rise to new islands of stability supported by relativistic mean field theoretic calculations. This is a manifestation of a new phenomenon where shell-effect overcomes the instability due to repulsive components of the nucleon-nucleon force broadening the stability peninsula. The two-neutron separation...
In-medium properties of strange vector mesons in dense and hot nuclear matter
International Nuclear Information System (INIS)
We investigate the in-medium properties of strange vector mesons (K* and anti K*) in dense and hot nuclear matter based on chirally motivated models of the meson self-energies. We parameterise medium effects as density or temperature dependent effective masses and widths, obtain the vector meson spectral functions within a Breit-Wigner prescription (which is often used in transport simulations), and study whether such an approach can retain the essential features of full microscopic calculations. For μB ≠ 0 the medium corrections arise from anti K* (K*) N scattering and the anti K* (K*) → anti K (K) π decay mode (accounting for in-medium anti K (K) dynamics). We calculate the scattering contribution to the K* self-energy based on the hidden local symmetry formalism for vector meson nucleon interactions, whereas for the anti K* self-energy we implement recent results from a self-consistent coupled-channel determination within the same approach. For μB ≅ 0 and finite temperature we rely on a phenomenological approach for the kaon self-energy in a hot pionic medium consistent with chiral symmetry, and evaluate the anti K* (K*) → anti K (K) π decay width. The emergence of a mass shift at finite temperature is studied with a dispersion relation over the imaginary part of the vector meson self-energy.
Nuclear matter EOS with light clusters within the mean-field approximation
Ferreira, Márcio
2013-01-01
The crust of a neutron star is essentially determined by the low-density region ($\\rho<\\rho_0\\approx0.15-0.16\\unit{fm}^{-3}$) of the equation of state. At the bottom of the inner crust, where the density is $\\rho\\lesssim0.1\\rho_0$, the formation of light clusters in nuclear matter will be energetically favorable at finite temperature. At very low densities and moderate temperatures, the few body correlations are expected to become important and light nuclei like deuterons, tritons, helions and $\\alpha$-particles will form. Due to Pauli blocking, these clusters will dissolve at higher densities $\\rho\\gtrsim 0.1\\rho_0$. The presence of these clusters influences the cooling process and quantities, such as the neutrino emissivity and gravitational waves emission. The dissolution density of these light clusters, treated as point-like particles, will be studied within the Relativistic Mean Field approximation. In particular, the dependence of the dissolution density on the clusters-meson couplings is studied.
Abplanalp, M.; Berger, C.; Czapek, G.; Diggelmann, U.; Furlan, M.; Gabutti, A.; Janos, S.; Moser, U.; Pozzi, R.; Pretzl, K.; Schmiemann, K.; Perret-Gallix, D.; Brandt, B. van den; Konter, J. A.; Mango, S.
1994-01-01
This work is part of an ongoing project to develop a Superheated Superconducting Granule (SSG) detector for cold dark matter and neutrinos. The response of SSG devices to nuclear recoils has been explored irradiating SSG detectors with a 70MeV neutron beam. The aim of the experiment was to test the sensitivity of Sn, Al and Zn SSG detectors to nuclear recoil energies down to a few keV. The detector consisted of a hollow teflon cylinder (0.1cm$^3$ inner volume) filled with tiny superconducting...
Chavarria, A E; Pena, J; Privitera, P; Robinson, A E; Scholz, B; Sengul, C; Zhou, J; Estrada, J; Izraelevitch, F; Tiffenberg, J; Neto, J R T de Mello; Machado, D Torres
2016-01-01
We report a measurement of the ionization efficiency of silicon nuclei recoiling with sub-keV kinetic energy in the bulk silicon of a charge-coupled device (CCD). Nuclear recoils were produced by low-energy neutrons ($<$24 keV) from a $^{124}$Sb-$^{9}$Be photoneutron source, and their ionization signal was measured down to 60 eV electron-equivalent. This energy range, previously unexplored, is relevant for the detection of low-mass dark matter particles. The measured efficiency was found to deviate from the extrapolation to low energies of Lindhard model. This measurement also demonstrates the sensitivity to nuclear recoils of CCDs employed by DAMIC, a dark matter direct detection experiment located in the SNOLAB underground laboratory.
Kondo effect of $\\bar{D}_{s}$ and $\\bar{D}_{s}^{\\ast}$ mesons in nuclear matter
Yasui, Shigehiro
2016-01-01
We study the Kondo effect for $\\bar{D}_{s}$ and $\\bar{D}_{s}^{\\ast}$ mesons as impurity particles in nuclear matter. The spin-exchange interaction between the $\\bar{D}_{s}$ or $\\bar{D}_{s}^{\\ast}$ meson and the nucleon induces the enhancement of the effective coupling in the low-energy scattering in the infrared region, whose scale of singularity is given by the Kondo scale. We investigate the Kondo scale in the renormalization group equation at nucleon one-loop level. We furthermore study the ground state with the Kondo effect in the mean-field approach, and present that the Kondo scale is related to the mixing strength between the $\\bar{D}_{s}$ or $\\bar{D}_{s}^{\\ast}$ meson and the nucleon in nuclear matter. We show the spectral function of the impurity when the Kondo effect occurs.
Relating the strangeness content of the nucleon with the mass shift of the ϕ meson in nuclear matter
Energy Technology Data Exchange (ETDEWEB)
Gubler, Philipp [ECT*, Villa Tambosi, 38123 Villazzano (Trento) (Italy); RIKEN, Nishina Center, Hirosawa 2-1, Wako, Saitama, 351-0198 (Japan); Ohtani, Keisuke [Tokyo Institute of Technology, Meguro 2-12-1, Tokyo 152-8551 (Japan)
2016-01-22
The behavior of the ϕ meson at finite density is studied, making use of a QCD sum rule approach in combination with the maximum entropy method. It is demonstrated that a possible mass shift of the ϕ in nuclear matter is strongly correlated to the strangeness content of the nucleon, which is proportional to the strange sigma term, σ{sub sN}. In contrast to earlier studies, our results show that, depending on the value of σ{sub sN}, the ϕ meson could receive both a positive or negative mass shift at nuclear matter density. We find that these results depend only weakly on potential modifications of the width of the ϕ meson peak and on assumptions made on the behavior of four-quark condensates at finite density.
Influence of nuclear matter fourth-order symmetry energy on neutron star crust-core phase transition
International Nuclear Information System (INIS)
In this work, we shall examine the critical importance of the fourth-order terms in the Taylor's series expansion in the prediction of the crust-core transition density. We shall perform the study in the Non-relativistic mean field approximation using finite range Simple Effective Interaction (SEI) that has been used in the finite nuclei and nuclear matter (NM) studies. We shall use the thermodynamics method to calculate the crust-core phase transition in neutron star
The chiral quark condensate and pion decay constant in nuclear matter at next-to-leading order
Lacour, A; Meißner, U -G
2010-01-01
Making use of the recently developed chiral power counting for the physics of nuclear matter [1,2], we evaluate the in-medium chiral quark condensate up to next-to-leading order for both symmetric nuclear matter and neutron matter. Our calculation includes the full in-medium iteration of the leading order local and one-pion exchange nucleon-nucleon interactions. Interestingly, we find a cancellation between the contributions stemming from the quark mass dependence of the nucleon mass appearing in the in-medium nucleon-nucleon interactions. Only the contributions originating from the explicit quark mass dependence of the pion mass survive. This cancellation is the reason of previous observations concerning the dominant role of the long-range pion contributions and the suppression of short-range nucleon-nucleon interactions. We find that the linear density contribution to the in-medium chiral quark condensate is only slightly modified for pure neutron matter by the nucleon-nucleon interactions. For symmetric nu...
Energy Technology Data Exchange (ETDEWEB)
Vasconcellos, C. A. Zen, E-mail: cesarzen@cesarzen.com [Instituto de Física, Universidade Federal do Rio Grande do Sul (UFRGS), Av. Bento Gonçalves 9500, 91501-970, Porto Alegre (Brazil); International Center for Relativistic Astrophysics Network (ICRANet), Piazza della Repubblica 10, 65122 Pescara (Italy)
2015-12-17
Nuclear science has developed many excellent theoretical models for many-body systems in the domain of the baryon-meson strong interaction for the nucleus and nuclear matter at low, medium and high densities. However, a full microscopic understanding of nuclear systems in the extreme density domain of compact stars is still lacking. The aim of this contribution is to shed some light on open questions facing the nuclear many-body problem at the very high density domain. Here we focus our attention on the conceptual issue of naturalness and its role in shaping the baryon-meson phase space dynamics in the description of the equation of state (EoS) of nuclear matter and neutrons stars. In particular, in order to stimulate possible new directions of research, we discuss relevant aspects of a recently developed relativistic effective theory for nuclear matter within Quantum Hadrodynamics (QHD) with genuine many-body forces and derivative natural parametric couplings. Among other topics we discuss in this work the connection of this theory with other known effective QHD models of the literature and its potentiality in describing a new physics for dense matter. The model with parameterized couplings exhausts the whole fundamental baryon octet (n, p, Σ{sup −}, Σ{sup 0}, Σ{sup +}, Λ, Ξ{sup −}, Ξ{sup 0}) and simulates n-order corrections to the minimal Yukawa baryon couplings by considering nonlinear self-couplings of meson fields and meson-meson interaction terms coupled to the baryon fields involving scalar-isoscalar (σ, σ∗), vector-isoscalar (ω, Φ), vector-isovector (ϱ) and scalar-isovector (δ) virtual sectors. Following recent experimental results, we consider in our calculations the extreme case where the Σ{sup −} experiences such a strong repulsion that its influence in the nuclear structure of a neutron star is excluded at all. A few examples of calculations of properties of neutron stars are shown and prospects for the future are discussed.
International Nuclear Information System (INIS)
The potential effect of organic matter in clay sealing materials on the performance of a nuclear fuel waste disposal vault was examined. The available data indicate that the engineering properties of clays are not significantly affected by the relatively low levels of organic matter (< 1.2 wt.%) present in the clay sealing materials. Complexing of radionuclides by organic substances that are released from the clay sealing materials or produced by microorganisms will likely inhibit rather than promote radionuclide mobility in the compacted sealing materials because of the relatively large size of organic complexing species. Decreasing the level of organic matter in the clay sealing materials will not eliminate microorganisms, and perhaps not decrease their numbers significantly, because chemolithotrophic microorganisms (microorganisms that utilize inorganic forms of C) will be present in a disposal vault. Furthermore, an examination of the nutrient budget in a disposal vault indicates that N, rather than C, will likely be the limiting nutrient for microbial growth. Finally, there is not suitable, proven method for decreasing the level of organic matter in the large amounts of clay needed to seal a vault. It is concluded that the organic matter present in the clay sealing material will not adversely affect the performance of a disposal vault
Dielectron spectroscopy in cold nuclear matter; Dielektronen-Spektroskopie in kalter Kernmaterie
Energy Technology Data Exchange (ETDEWEB)
Weber, Michael
2011-02-18
The subject of this thesis is the production of light mesons and baryonic resonances in p+Nb collisions at E{sub kin}=3.5 GeV via their decay in e{sup +}e{sup -} pairs and their kinematic observables. This reaction system in particular allows for the production of vector mesons in approximately cold nuclear matter and the study of expected in-medium effects. The experiment was conducted at the dielectron spectrometer HADES at GSI Helmholtzzentrum fuer Schwerionenforschung GmbH. In total, 64827{+-}294 signal pairs with an pair opening angle {alpha}{sub ee}>9 and e{sup +}/e{sup -} momenta 80
550 MeV/c{sup 2}). Inclusive e{sup +}e{sup -} production cross sections inside the HADES acceptance were calculated by analyzing the simultaneously measured charged pions and by comparing the obtained {pi}{sup -} yields to an independent data set. For the vector mesons one obtains {sigma}{sub {omega}}{sub ,acc}=(65.8{+-}4.6(stat){+-}18.4(sys)) nb and {sigma}{sub {phi}}{sub ,acc}=(7.8{+-}1.7(stat){+-}2.2 (sys)) nb. A comparison with cross sections in free p+p collisions at E{sub kin}=3.5 GeV results in the nuclear modification factors R{sub pA} as well as their scaling {alpha} with the nuclear mass number A and their dependence on the pair lab momenta p{sub ee}. While absorption is not important for the {phi} meson ({alpha}{sub {phi}} {approx}1), scaling factors {alpha} {approx}0.7 are established for the quasi free decay (p{sub ee}>800 MeV/c) of all other hadrons. From an adapted Glauber model calculation a minimal absorption >or similar 35% of all contributing hadrons in nuclei can be deduced. At smaller pair momenta different scaling factors are obtained. The {omega} meson is absorbed with a higher probability ({alpha}{sub {omega}}=0.62), but for all other sources above the {pi}{sup 0
Exact solution of equations for proton localization in neutron star matter
Kubis, Sebastian
2016-01-01
The rigorous treatment of proton localization phenomenon in asymmetric nuclear matter is presented. The solution of proton wave function and neutron background distribution is found by the use of the extended Thomas-Fermi approach. The minimum of energy is obtained in the Wigner- Seitz approximation of spherically symmetric cell. The analysis of three different nuclear models suggests that the proton localization is likely to take place in the interior of neutron star.
Directional detection of dark matter in universal bound states
Laha, Ranjan
2015-01-01
It has been suggested that several small-scale structure anomalies in $\\Lambda$CDM cosmology can be solved by strong self-interaction between dark matter particles. It was shown by Braaten and Hammer that the presence of a near threshold S-wave resonance can make the scattering cross section at nonrelativistic speeds come close to saturating the unitarity bound. This can result in the formation of a stable bound state of two asymmetric dark matter particles (which we call darkonium). Laha and Braaten studied the nuclear recoil energy spectrum in dark matter direct detection experiments due to this incident bound state. Here we study the angular recoil spectrum, and show that it is uniquely determined up to normalization by the S-wave scattering length. Observing this angular recoil spectrum in a dark matter directional detection experiment will uniquely determine many of the low-energy properties of dark matter independent of the underlying dark matter microphysics.
Directional detection of dark matter in universal bound states
Energy Technology Data Exchange (ETDEWEB)
Laha, Ranjan
2015-10-01
It has been suggested that several small-scale structure anomalies in CDM cosmology can be solved by strong self-interaction between dark matter particles. It was shown in Ref. [1] that the presence of a near threshold S-wave resonance can make the scattering cross section at nonrelativistic speeds come close to saturating the unitarity bound. This can result in the formation of a stable bound state of two asymmetric dark matter particles (which we call darkonium). Ref. [2] studied the nuclear recoil energy spectrum in dark matter direct detection experiments due to this incident bound state. Here we study the angular recoil spectrum, and show that it is uniquely determined up to normalization by the S-wave scattering length. Observing this angular recoil spectrum in a dark matter directional detection experiment will uniquely determine many of the low-energy properties of dark matter independent of the underlying dark matter microphysics.
Nuclear forces and the properties of matter at high temperature and density
Energy Technology Data Exchange (ETDEWEB)
Rayet, M.; Arnould, M.; Paulus, G.; Tondeur, F.
1982-12-01
We present two Skyrme-type forces which are particularly well suited for the description of presupernova core or matter in nascent neutron star. They are compared to other forces currently used in this field, with regard to finite nuclei and infinite matter properties, and to the coexistence of nuclei in a hot and dense nucleon gas.
Energy Technology Data Exchange (ETDEWEB)
Bernardos, P. [Universidad de Cantabria, Departamento de Matematica Aplicada y Ciencias de la Computacion, 39005, Santander (Spain); Fomenko, V.N. [St Petersburg University for Railway Engineering, Department of Mathematics, 190031, St Petersburg (Russian Federation); Marcos, S.; Niembro, R. [Universidad de Cantabria, Departamento de Fisica Moderna, 39005, Santander (Spain); Lopez-Quelle, M. [Universidad de Cantabria, Departamento de Fisica Aplicada, 39005, Santander (Spain); Savushkin, L.N. [St Petersburg University for Telecommunications, Department of Physics, 191186, St Petersburg (Russian Federation)
2001-02-01
An effective nuclear model describing {omega}-, {rho}- and axial-mesons as gauge fields is applied to nuclear matter in the relativistic Hartree-Fock approximation. The isoscalar two-pion exchange is simulated by a scalar field s similar to that used in the conventional relativistic mean-field approach. Two more scalar fields are essential ingredients of the present treatment: the {sigma}-field, the chiral partner of the pion, and the {sigma}-field, the Higgs field for the {omega}-meson. Two versions of the model are used depending on whether the {sigma}-field is considered as a dynamical variable or 'frozen', by taking its mass as infinite. The model contains four free parameters in the first case and three in the second one which are fitted to the nuclear matter saturation conditions. The nucleon and meson effective masses, compressibility modulus and symmetry energy are calculated. The results prove the reliability of the Dirac-Hartree-Fock approach within the linear realization of the chiral symmetry. (author)
International Nuclear Information System (INIS)
The objective of the Sedimentary Rock Program at the Oak Ridge National Laboratory is to conduct investigations to assess the potential for shale to serve as a host medium for the isolation of high-level nuclear wastes. The emphasis on shale is a result of screening major sedimentary rock types (shale, sandstone, carbonate , anhydrite, and chalk) for a variety of attributes that affect the performance of repositories. The retardation of radionuclides was recognized as one of the potentially favorable features of shale. Because shale contains both clay minerals and organic matter, phases that may provide significant sorption of radioelement, the characterization of these phases is essential. In addition, the organic matter in shale has been identified as a critical area for study because of its potential to play either a favorable (reductant) or deleterious (organic ligands) role in the performance of a repository sited in shale. 36 refs., 36 figs., 10 tabs
Kim, Jeong Sik; Koo, Dae Lim; Joo, Eun Yeon; Kim, Sung Tae; Seo, Dae Won
2016-01-01
Background and Purpose This study aimed to estimate the changes in gray matter volume (GMV) and their hemispheric difference in patients with mesial temporal lobe epilepsy (MTLE) using a voxel-based morphometry (VBM) methodology, and to determine whether GMV changes are correlated with clinical features. Methods VBM analysis of brain MRI using statistical parametric mapping 8 (SPM8) was performed for 30 left MTLE (LMTLE) and 30 right MTLE (RMTLE) patients and 30 age- and sex-matched healthy controls. We also analyzed the correlations between GMV changes and clinical features of MTLE patients. Results In SPM8-based analyses, MTLE patients showed significant GMV reductions in the hippocampus ipsilateral to the epileptic focus, bilateral thalamus, and contralateral putamen in LMTLE patients. The GMV reductions were more extensive in the ipsilateral hippocampus, thalamus, caudate, putamen, uncus, insula, inferior temporal gyrus, middle occipital gyrus, cerebellum, and paracentral lobule in RMTLE patients. These patients also exhibited notable reductions of GMV in the contralateral hippocampus, thalamus, caudate, putamen, and inferior frontal gyrus. We observed that GMV reduction was positively correlated with several clinical features (epilepsy duration and seizure frequency in RMTLE, and history of febrile seizure in LMTLE) and negatively correlated with seizure onset age in both the RMTLE and LMTLE groups. Conclusions Our study revealed GMV decreases in the hippocampus and extrahippocampal regions. Furthermore, the GMV reduction was more extensive in the RMTLE group than in the LMTLE group, since it included the contralateral hemisphere in the former. This difference in the GMV reduction patterns between LMTLE and RMTLE may be related to a longer epilepsy duration and higher seizure frequency in the latter.
2013-05-14
... FR 49139; August 28, 2007). The E-Filing process requires participants to submit and serve all... Nuclear Plant (FNP), Units 1 and 2, in accordance with conditions specified therein. The facility is... investigation, the NRC issued a letter to FNP dated January 9, 2013, which documented an apparent violation...
Excitation function of elliptic flow in Au+Au collisions and the nuclear matter equation of state
Andronic, A; Basrak, Z; Bastid, N; Benabderrahmane, L; Berek, G; Caplar, R; Cordier, E; Crochet, Philippe; Dupieux, P; Dzelalija, M; Fodor, Z; Gasparic, I; Grishkin, Yu; Hartmann, O N; Herrmann, N; Hildenbrand, K D; Hong, B; Kecskeméti, J; Kim, Y J; Kirejczyk, M; Koczón, P; Korolija, M; Kotte, R; Kress, T; Lebedev, A; Leifels, Y; López, X; Mangiarotti, A; Merschmeyer, M; Neubert, W; Pelte, D; Petrovici, M; Rami, F; Reisdorf, W; de Schauenburg, B; Schüttauf, A; Seres, Z; Sikora, B; Sim, K S; Simion, V; Siwek-Wilczynska, K; Smolyankin, V T; Stockmeier, M R; Stoicea, G; Tyminski, Z; Wagner, P; Wisniewski, K; Wohlfarth, D; Xiao, Z G; Yushmanov, I E; Zhilin, A
2005-01-01
We present measurements of the excitation function of elliptic flow at midrapidity in Au+Au collisions at beam energies from 0.09 to 1.49 GeV per nucleon. For the integral flow, we discuss the interplay between collective expansion and spectator shadowing for three centrality classes. A complete excitation function of transverse momentum dependence of elliptic flow is presented for the first time in this energy range, revealing a rapid change with incident energy below 0.4 AGeV, followed by an almost perfect scaling at the higher energies. The equation of state of compressed nuclear matter is addressed through comparisons to microscopic transport model calculations.
Hartree-Fock approach to nuclear matter and finite nuclei with M3Y-type nucleon-nucleon interactions
Nakada, H
2003-01-01
By introducing a density-dependent contact term, M3Y-type interactions applicable to the Hartree-Fock calculations are developed. In order to view basic characters of the interactions, we carry out calculations on the uniform nuclear matter as well as on several doubly magic nuclei. It is shown that a parameter-set called M3Y-P2 describes various properties similarly well to the Skyrme SLy5 and/or the Gogny D1S interactions. A remarkable difference from the SLy5 and the D1S interactions is fo...
DEFF Research Database (Denmark)
da Providëncia, J.; Jalkanen, Karl J.; Bohr, Henrik
2013-01-01
as they possibly relate to chirality of nuclei (atoms) in molecules as a source of chirality in amino acids and hence in life. Previous works have not investigated the nuclear forces as a possible bias which initiated the bias towards L-amino acids as the building blocks on proteins, and later life.......Superconductivity is described by the well-known Bardeen-Cooper-Schrieffer (BCS) theory, which is a symmetry breaking approximation. Color superconductivity shows up in extremely high density matter and temperature, which is here investigated and compared to the other end of the scale of low energy...
International Nuclear Information System (INIS)
We present a new analysis of J/ψ production yields in deuteron-gold collisions at √(sNN)=200 GeV using data taken from the PHENIX experiment in 2003 and previously published in S. S. Adler et al. [Phys. Rev. Lett 96, 012304 (2006)]. The high statistics proton-proton J/ψ data taken in 2005 are used to improve the baseline measurement and thus construct updated cold nuclear matter modification factors (RdAu). A suppression of J/ψ in cold nuclear matter is observed as one goes forward in rapidity (in the deuteron-going direction), corresponding to a region more sensitive to initial-state low-x gluons in the gold nucleus. The measured nuclear modification factors are compared to theoretical calculations of nuclear shadowing to which a J/ψ (or precursor) breakup cross section is added. Breakup cross sections of σbreakup=2.8-1.4+1.7 (2.2-1.5+1.6) mb are obtained by fitting these calculations to the data using two different models of nuclear shadowing. These breakup cross-section values are consistent within large uncertainties with the 4.2±0.5 mb determined at lower collision energies. Projecting this range of cold nuclear matter effects to copper-copper and gold-gold collisions reveals that the current constraints are not sufficient to firmly quantify the additional hot nuclear matter effect
2010-01-29
... rule (72 FR 49139, August 28, 2007). The E-Filing process requires participants to submit and serve all... Gamma Nuclear Radiology; Confirmatory Order Modifying License (Effective Immediately) I Beta Gamma Nuclear Radiology (BGNR) (Licensee) is the holder of medical License No. 52-25542-01, issued by the...
Spontaneous baryogenesis from asymmetric inflaton
Energy Technology Data Exchange (ETDEWEB)
Takahashi, Fuminobu [Tohoku Univ., Sendai (Japan). Dept. of Physics; Tokyo Univ., Chiba (Japan). Kavli IPMU (WPI), UTIAS; Yamada, Masaki [Tokyo Univ., Chiba (Japan). Kavli IPMU (WPI), UTIAS; Tokyo Univ., Chiba (Japan). Inst. for Cosmic Ray Research; DESY Hamburg (Germany)
2015-10-15
We propose a variant scenario of spontaneous baryogenesis from asymmetric inflaton based on current-current interactions between the inflaton and matter fields with a non-zero B-L charge. When the inflaton starts to oscillate around the minimum after inflation, it may lead to excitation of a CP-odd component, which induces an effective chemical potential for the B-L number through the current-current interactions. We study concrete inflation models and show that the spontaneous baryogenesis scenario can be naturally implemented in the chaotic inflation in supergravity.
A modified explanation of cold nuclear matter effects on J/ψ production in p+A collisions
Liu, Zhi-Feng
2015-08-01
A modified explanation of the cold nuclear matter (CNM) effects on J/ψ production in p+A collisions is presented in this paper. The advantage of the modified explanation is that all the CNM effects implemented in this model have clear physical origins and are mostly centered on the idea of multiple parton scattering. With the CNM effects presented in this paper, we calculated the nuclear modification factor RpA in J/ψ production under different collision energies. The results are compared with the corresponding experiment data and the factors calculated with classic nuclear effects. The factors calculated with CNM effects presented in this paper can accurately reproduce almost all existing J/ψ measurements in p-A collisions, which is much better than results obtained with the factors calculated with classic nuclear effects. The new model is therefore a more suitable approach to explain CNM effects in the hardproduction of quarkonium. Supported by National Nature Science Foundation of China (10575028)