Showing papers on "Nuclear matter published in 2013"
TL;DR: In this paper, a spherically symmetric core-collapse supernova model based on general relativistic radiation hydrodynamics with three-flavor Boltzmann neutrino transport is proposed.
Abstract: Many of the currently available equations of state for core-collapse supernova simulations give large neutron star radii and do not provide large enough neutron star masses, both of which are inconsistent with some recent neutron star observations. In addition, one of the critical uncertainties in the nucleon-nucleon interaction, the nuclear symmetry energy, is not fully explored by the currently available equations of state. In this article, we construct two new equations of state which match recent neutron star observations and provide more flexibility in studying the dependence on nuclear matter properties. The equations of state are also provided in tabular form, covering a wide range in density, temperature, and asymmetry, suitable for astrophysical simulations. These new equations of state are implemented into our spherically symmetric core-collapse supernova model, which is based on general relativistic radiation hydrodynamics with three-flavor Boltzmann neutrino transport. The results are compared with commonly used equations of state in supernova simulations of 11.2 and 40 M ☉ progenitors. We consider only equations of state which are fitted to nuclear binding energies and other experimental and observational constraints. We find that central densities at bounce are weakly correlated with L and that there is a moderate influence of the symmetry energy on the evolution of the electron fraction. The new models also obey the previously observed correlation between the time to black hole formation and the maximum mass of an s = 4 neutron star.
556 citations
TL;DR: In this article, a 1.97 +/- 0.04 M-circle dot neutron star was observed to have sub-and supranuclear densities, which constrain the equation of state of neutron-rich matter.
Abstract: Microscopic calculations of neutron matter based on nuclear interactions derived from chiral effective field theory, combined with the recent observation of a 1.97 +/- 0.04 M-circle dot neutron star, constrain the equation of state of neutron-rich matter at sub-and supranuclear densities. We discuss in detail the allowed equations of state and the impact of our results on the structure of neutron stars, the crust-core transition density, and the nuclear symmetry energy. In particular, we show that the predicted range for neutron star radii is robust. For use in astrophysical simulations, we provide detailed numerical tables for a representative set of equations of state consistent with these constraints.
445 citations
TL;DR: In this paper, it was shown that the radius of a 1.4 solar mass neutron star lies between 10.4 and 12.9 km, independent of assumptions about the composition of the core.
Abstract: The equation of state (EOS) of dense matter has been a long-sought goal of nuclear physics. EOSs generate unique mass versus radius (M-R) relations for neutron stars, the ultra-dense remnants of stellar evolution. In this work, we determine the neutron star mass-radius relation and, based on recent observations of both transiently accreting and bursting sources, we show that the radius of a 1.4 solar mass neutron star lies between 10.4 and 12.9 km, independent of assumptions about the composition of the core. We show, for the first time, that these constraints remain valid upon removal from our sample of the most extreme transient sources or of the entire set of bursting sources; our constraints also apply even if deconfined quark matter exists in the neutron star core. Our results significantly constrain the dense matter EOS and are furthermore consistent with constraints from both heavy-ion collisions and theoretical studies of neutron matter. We predict a relatively weak dependence of the symmetry energy on the density and a value for the neutron skin thickness of lead which is less than 0.20 fm, results that are testable in forthcoming experiments.
441 citations
TL;DR: In this paper, it was shown that fits of nuclear masses to experimental masses, combined with other experimental information from neutron skins, heavy ion collisions, giant dipole resonances and dipole polarizabilities, lead to stringent constraints on parameters that describe the symmetry energy near the nuclear saturation density.
Abstract: One of the major uncertainties in the dense matter equation of state has been the nuclear symmetry energy. The density dependence of the symmetry energy is important in nuclear astrophysics, as it controls the neutronization of matter in core-collapse supernovae, the radii of neutron stars and the thicknesses of their crusts, the rate of cooling of neutron stars, and the properties of nuclei involved in r-process nucleosynthesis. We show that fits of nuclear masses to experimental masses, combined with other experimental information from neutron skins, heavy ion collisions, giant dipole resonances and dipole polarizabilities, lead to stringent constraints on parameters that describe the symmetry energy near the nuclear saturation density. These constraints are remarkably consistent with inferences from theoretical calculations of pure neutron matter, and, furthermore, with astrophysical observations of neutron stars. The concordance of experimental, theoretical and observational analyses suggests that the symmetry parameters S v and L are in the range 29.0‐32.7 MeV and 40.5‐61.9 MeV, respectively, and that the neutron star radius, for a 1.4 M star, is in the narrow window 10.7 km < R < 13.1 km (90% confidence). We can also set tight limits to the size of neutron star crusts and the fractional moment of inertia they contain, as well as the overall moment of inertia and quadrupole polarizability of 1.4 M stars. Our results also have implications for the disk mass and ejected mass of compact mergers involving neutron stars.
389 citations
TL;DR: In this article, the authors study the mass-radius curve of hybrid stars, assuming a single first-order phase transition between nuclear and quark matter, with a sharp interface between the quark core and nuclear matter mantle.
Abstract: We study the mass-radius curve of hybrid stars, assuming a single first-order phase transition between nuclear and quark matter, with a sharp interface between the quark matter core and nuclear matter mantle. We use a generic parametrization of the quark matter equation of state, which has a constant, i.e. density-independent, speed of sound. We argue that this parametrization provides a framework for comparison and empirical testing of models of quark matter. We obtain the phase diagram of possible forms of the hybrid star mass-radius relation, where the control parameters are the transition pressure, energy density discontinuity, and the quark matter speed of sound. We find that this diagram is sensitive to the quark matter parameters but fairly insensitive to details of the nuclear matter equation of state (EoS). We calculate the maximum hybrid star mass as a function of the parameters of the quark matter EoS, and find that there are reasonable values of those parameters that give rise to hybrid stars with mass above $2{M}_{\ensuremath{\bigodot}}$.
350 citations
TL;DR: This work presents the first complete N(3)LO calculation of the neutron matter energy, which includes the subleading three-nucleon forces for the first time and all leading four-n nucleon forces.
Abstract: Neutron matter presents a unique system for chiral effective field theory because all many-body forces among neutrons are predicted to next-to-next-to-next-to-leading order (${\mathrm{N}}^{3}\mathrm{LO}$). We present the first complete ${\mathrm{N}}^{3}\mathrm{LO}$ calculation of the neutron matter energy. This includes the subleading three-nucleon forces for the first time and all leading four-nucleon forces. We find relatively large contributions from ${\mathrm{N}}^{3}\mathrm{LO}$ three-nucleon forces. Our results provide constraints for neutron-rich matter in astrophysics with controlled theoretical uncertainties.
280 citations
TL;DR: This work paves the way for QMC calculations with systematic chiral EFT interactions for nuclei and nuclear matter, for testing the perturbativeness of different orders, and allows for matching to lattice QCD results by varying the pion mass.
Abstract: We present the first quantum Monte Carlo (QMC) calculations with chiral effective field theory (EFT) interactions. To achieve this, we remove all sources of nonlocality, which hamper the inclusion in QMC calculations, in nuclear forces to next-to-next-to-leading order. We perform auxiliary-field diffusion Monte Carlo (AFDMC) calculations for the neutron matter energy up to saturation density based on local leading-order, next-to-leading order, and next-to-next-to-leading order nucleon-nucleon interactions. Our results exhibit a systematic order-by-order convergence in chiral EFT and provide nonperturbative benchmarks with theoretical uncertainties. For the softer interactions, perturbative calculations are in excellent agreement with the AFDMC results. This work paves the way for QMC calculations with systematic chiral EFT interactions for nuclei and nuclear matter, for testing the perturbativeness of different orders, and allows for matching to lattice QCD results by varying the pion mass.
255 citations
TL;DR: In this paper, the Hartree-Fock-Bogoliubov (HFB) mass models are extended by fitting to the 2012 Atomic Mass Evaluation (AME), and varying the symmetry coefficient $J$.
Abstract: Our family of three Hartree-Fock-Bogoliubov (HFB) mass models, labeled BSk19, BSk20, and BSk21, is here extended by (a) refitting to the 2012 Atomic Mass Evaluation (AME), and (b) varying the symmetry coefficient $J$. Five new models, labeled BSk22 to BSk26, along with their mass tables, HFB-22 to HFB-26, respectively, are presented. These models are characterized by unconventional Skyrme forces containing ${t}_{4}$ and ${t}_{5}$ terms, i.e., density-dependent generalizations of the usual ${t}_{1}$ and ${t}_{2}$ terms, respectively. Highly realistic contact pairing forces are used. The Skyrme forces are constrained to fit realistic equations of state of neutron matter stiff enough to support the massive neutron stars PSR J1614$\ensuremath{-}$2230 and PSR J0348+0432. Unphysical spin and spin-isospin instabilities of homogeneous nuclear matter, including the transition to a polarized state in neutron-star matter, are eliminated with the new forces. The best fits to the new database of 2353 nuclei are found for models BSk24 ($J=30$ MeV) and BSk25 ($J=29$ MeV), for which the root-mean square (rms) deviations are 0.55 and 0.54 MeV, respectively. Despite the larger database this is even better than the rms deviation of 0.58 MeV that we found with our fits to the 2003 AME. With $J=32$ MeV the rms deviation rises to 0.63 MeV. The neutron-skin thicknesses derived from antiproton scattering are shown to be consistent with the conclusions that we have drawn from masses.
247 citations
TL;DR: In this article, a review of theoretical approaches to explore the phase diagram of nuclear and quark matter at high baryon density is presented, with emphasis put on the relevance to quark-matter.
209 citations
TL;DR: In this paper, the effects of parton energy loss in cold nuclear matter on heavy-quarkonium suppression in p-A collisions were studied, and it was shown from first principles that the medium induced energy loss scales as E.
Abstract: The effects of parton energy loss in cold nuclear matter on heavy-quarkonium suppression in p-A collisions are studied. It is shown from first principles that at large quarkonium energy E and small production angle in the nucleus rest frame, the medium- induced energy loss scales as E. Using this result, a phenomenological model depending on a single free parameter is able to reproduce J/ψ andsuppression data in a broad x F - range and at various center-of-mass energies. These results strongly support energy loss as the dominant effect in heavy-quarkonium suppression in p-A collisions. Predictions for J/ψ andsuppression in p-Pb collisions at the LHC are made. It is argued that parton energy loss scaling as E should generally apply to hadron production in p-A collisions, such as light hadron or open charm production.
205 citations
TL;DR: Here it is shown how to engineer quantum simulators of non-Abelian lattice gauge theories, which can be used to mimic quark confinement or to study dimer and valence-bond states (which may be relevant for high-temperature superconductors).
Abstract: Many phenomena occurring in strongly correlated quantum systems still await conclusive explanations. The absence of isolated free quarks in nature is an example. It is attributed to quark confinement, whose origin is not yet understood. The phase diagram for nuclear matter at general temperatures and densities, studied in heavy-ion collisions, is not settled. Finally, we have no definitive theory of high-temperature superconductivity. Though we have theories that could underlie such physics, we lack the tools to determine the experimental consequences of these theories. Quantum simulators may provide such tools. Here we show how to engineer quantum simulators of non-Abelian lattice gauge theories. The systems we consider have several applications: they can be used to mimic quark confinement or to study dimer and valence-bond states (which may be relevant for high-temperature superconductors).
TL;DR: In this article, an exact analytical solution for the space-time evolution of electromagnetic field in electrically conducting nuclear matter produced in heavy-ion collisions is discussed, and it is argued that the parameter that controls the strength of the matter effect on the field evolution is Ω(ensuremath{\sigma}\ensureMath{\gamma}b), where Ω is the Lorentz boost-factor, and b is the characteristic transverse size of matter.
Abstract: Exact analytical solution for the space-time evolution of electromagnetic field in electrically conducting nuclear matter produced in heavy-ion collisions is discussed. It is argued that the parameter that controls the strength of the matter effect on the field evolution is $\ensuremath{\sigma}\ensuremath{\gamma}b$, where $\ensuremath{\sigma}$ is electrical conductivity, $\ensuremath{\gamma}$ is the Lorentz boost-factor, and $b$ is the characteristic transverse size of the matter. When this parameter is of the order 1 or larger, which is the case at the Relativistic Heavy Ion Collider and the Large Hadron Collider, the space-time dependence of the electromagnetic field completely differs from that in vacuum.
TL;DR: In this article, the authors presented the first complete N${}^{3}$LO calculation of the neutron-matter energy, which includes the sub-leading three-nucleon as well as the leading four-Nucleon forces, and provided theoretical uncertainties.
Abstract: The neutron-matter equation of state constrains the properties of many physical systems over a wide density range and can be studied systematically using chiral effective field theory (EFT). In chiral EFT, all many-body forces among neutrons are predicted to next-to-next-to-next-to-leading order (N${}^{3}$LO). We present details and additional results of the first complete N${}^{3}$LO calculation of the neutron-matter energy, which includes the subleading three-nucleon as well as the leading four-nucleon forces, and provides theoretical uncertainties. In addition, we discuss the impact of our results for astrophysics: for the supernova equation of state, the symmetry energy and its density derivative, and for the structure of neutron stars. Finally, we give a first estimate for the size of the N${}^{3}$LO many-body contributions to the energy of symmetric nuclear matter, which shows that their inclusion will be important in nuclear structure calculations.
TL;DR: In this paper, the authors show that the maximum mass (M max) of neutron stars with quark matter cores can be larger than those without quark-matter cores, in contrast to the conventional softening of the equation of state due to exotic components at high density.
Abstract: Using the idea of smooth crossover from hadronic matter with hyperons to quark matter with strangeness, we show that the maximum mass (M max) of neutron stars with quark matter cores can be larger than those without quark matter cores. This is in contrast to the conventional softening of the equation of state due to exotic components at high density. The essential conditions for reaching our conclusion are that (1) the crossover takes place at relatively low densities, around three times the normal nuclear density and (2) the quark matter is strongly interacting in the crossover region. From these, the pressure of the system can be greater than that of purely hadronic matter at a given baryon density in the crossover density region and leads to M max greater than 2 solar mass. This conclusion is insensitive to the different choice of the hadronic equation of state with hyperons. We remark upon several implications of this result to the nuclear incompressibility, the hyperon mixing, and the neutrino cooling.
TL;DR: In this article, a fixed-target experiment using the proton and lead-ion beams of the LHC extracted by a bent crystal was proposed, and the results showed that the beam can be used to study the properties of the Sivers single-spin asymmetry, the transversity distribution and possibly of polarized parton distributions.
TL;DR: In this article, the yields of quarkonia in heavy ion collisions at RHIC and the LHC were calculated as a function of their transverse momentum, including color-singlet and color-octet contributions and feeddown effects from excited states.
Abstract: We calculate the yields of quarkonia in heavy ion collisions at RHIC and the LHC as a function of their transverse momentum. Based upon non-relativistic quantum chromodynamics, our results include both color-singlet and color-octet contributions and feed-down effects from excited states. In reactions with ultra-relativistic nuclei, we focus on the consistent implementation of dynamically calculated nuclear matter effects, such as coherent power corrections, cold nuclear matter energy loss, and the Cronin effect in the initial state. In the final state, we consider radiative energy loss for the color-octet state and collisional dissociation of quarkonia as they traverse through the QGP. Theoretical results are presented for J/psi and Upsilon and compared to experimental data where applicable. At RHIC, a good description of the high-pT J/psi modification observed in central Cu+Cu and Au+Au collisions can be achieved within the model uncertainties. We find that measurements of J/psi yields in proton-nucleus reactions are needed to constrain the magnitude of cold nuclear matter effects. At the LHC, a good description of the experimental data can be achieved only in mid-central and peripheral Pb+Pb collisions. The large five-fold suppression of prompt J/psi in the most central nuclear reactions may indicate for the first time possible thermal effects at the level of the quarkonium wavefunction at large transverse momenta.
TL;DR: In this paper, a new equation of state (EOS) with the pressure interpolated as a function of the baryon density was constructed for the percolation picture from the hadronic phase with hyperons to the quark phase with strangeness, where the crossover from hadronic matter to quark matter takes place at around three times the normal nuclear matter density.
Abstract: On the basis of the percolation picture from the hadronic phase with hyperons to the quark phase with strangeness, we construct a new equation of state (EOS) with the pressure interpolated as a function of the baryon density. The maximum mass of neutron stars can exceed $2M_{\odot }$ if the following two conditions are satisfied: (i) the crossover from hadronic matter to quark matter takes place at around three times the normal nuclear matter density, and (ii) the quark matter is strongly interacting in the crossover region and has a stiff equation of state. This is in contrast to the conventional approach, assuming the first-order phase transition in which the EOS always becomes soft due to the presence of the quark matter at high density. Although the choice of the hadronic EOS does not affect the above conclusion for the maximum mass, the three-body force among nucleons and hyperons plays an essential role in the onset of hyperon mixing and the cooling of neutron stars.
TL;DR: In this paper, a new Hartree-Fock-Bogoliubov nuclear mass model based on standard forms of Skyrme and pairing functionals is presented, which corresponds to the most accurate mass model ever achieved within the framework of the nuclear energy density functional theory.
Abstract: We present a new Hartree-Fock-Bogoliubov nuclear mass model based on standard forms of Skyrme and pairing functionals, which corresponds to the most accurate mass model we ever achieved within the framework of the nuclear energy density functional theory. Our new mass model is characterized by a model standard deviation ${\ensuremath{\sigma}}_{\mathrm{mod}}=0.500$ MeV with respect to essentially all the 2353 available mass data for nuclei with neutron and proton numbers larger than 8. At the same time, the underlying Skyrme functional yields a realistic description of infinite homogeneous nuclear matter properties, as determined by realistic calculations and by experiments; these include in particular the incompressibility coefficient, the pressure in charge-symmetric nuclear matter, the neutron-proton effective mass splitting, the stability against spin and spin-isospin fluctuations, as well as the neutron-matter equation of state.
TL;DR: In this article, it was shown that the peculiar early optical emission and the X-ray after glow emission of the short-duration burst GRB 130603B can be explained by continuous energy injection into the blastwave from a supramassive magnetar central engine.
Abstract: We show that the peculiar early optical emission and, in particular, the X-ray after glow emission of the short-duration burst GRB 130603B can be explained by continuous energy injection into the blastwave from a supramassive magnetar central engine. The observed energetics and temporal/spectral properties of the late infrared bump (i.e., the "kilonova") are also found to be consistent with emission from the ejecta launched during a neutron star (NS)-NS merger and powered by a magnetar central engine. The isotropic-equivalent kinetic energies of both the gamma-ray burst (GRB) blastwave and the kilonova are approximately E-k similar to 10(51) erg, consistent with being powered by a near-isotropic magnetar wind. However, this relatively small value requires that most of the initial rotational energy of the magnetar (similar to a few x 10(52) erg) is carried away by gravitational wave radiation. Our results suggest that (1) the progenitor of GRB 130603B was a NS-NS binary system, the merger product of which would have been a supramassive NS that lasted for about similar to 1000 s; (2) the equation of state of the nuclear matter should be stiff enough to allow the survival of a long-lived supramassive NS; thus this suggested that the detection of the bright electromagnetic counterparts of gravitational wave triggers without short GRB associations is promising in the upcoming Advanced LIGO/VIRGO era.
TL;DR: In this paper, a theoretical framework applicable to the nonzero angular-momentum pairing including the coupling due to tensor force is given by extending the usual BCS-Bogoliubov theory for the 0-1S-0 pairing.
Abstract: Nucleon superfluids which are realized in neutron star interior and symmetric nuclear matter are studied with use of realistic nuclear forces, in the density domain from the subnuclear region to about 3ρ_0 (ρ_0 being the nuclear density). It is shown that characteristic aspects of nuclear forces manifest themselves in the appearance of several kinds of nucleon superfluids, which strongly depends on the density ρ. In this chapter emphasis is put on the pairing correlations where strong noncentral (tensor and spin-orbit) forces play important roles. A theoretical framework applicable to the nonzero angular-momentum pairing including the coupling due to tensor force is given by extending the usual BCS-Bogoliubov theory for the ^1S_0 pairing (the zero angular-momentum one). This formulation has been applied to the ^3P_2+^3F_2 pairing in neutron matter (the dominant component of neutron stars) and the ^3S_1+^3D_1 pairing in symmetric nuclear matter. In the former case, although spin-orbit force mainly contributes to the ^3P_2 attraction, the tensor coupling with the ^3F_2 component assists to realize the ^3P_2 superfluid. In the latter case, the tensor coupling to the ^3D_1 component plays a vital role to realize the ^3S_1 superfluid with a large energy gap. Results of the energy gaps calculated for such nonzero angular-momentum pairings, as well as those for the ^1S_0 pairing, are shown. We have found the realization of the following nucleon superfluids; the neutron ^3P_2 superfluid and the proton ^1S_0 one in the fluid core of neutron stars at ρ≃(0.7∼3)ρ_0, the neutron ^1S_0 superfluid in the inner crust of neutron stars at ρ≃(10^−3∼0.5)ρ_0, and the ^3S_1 superfluid in symmetric nuclear matter at a wide range of ρ including ρ_0, contrary to the ^1S_0 one realized at ρ≲ρ_0/2. The properties of these superfluids and their implications are also discussed.
TL;DR: In this article, the isovector giant quadrupole resonance (IVGQR) was analyzed in the A=208 mass region using both macroscopic and microscopic approaches.
Abstract: Recent improvements in the experimental determination of properties of the isovector giant quadrupole resonance (IVGQR), as demonstrated in the A=208 mass region, may be instrumental for characterizing the isovector channel of the effective nuclear interaction. We analyze properties of the IVGQR in 208Pb, using both macroscopic and microscopic approaches. The microscopic method is based on families of nonrelativistic and covariant energy density functionals (EDF), characterized by a systematic variation of isoscalar and isovector properties of the corresponding nuclear matter equations of state. The macroscopic approach yields an explicit dependence of the nuclear symmetry energy at some subsaturation density, for instance S(ρ=0.1 fm−3), or the neutron skin thickness Δrnp of a heavy nucleus, on the excitation energies of isoscalar and isovector GQRs. Using available data it is found that S(ρ=0.1 fm−3)=23.3±0.6 MeV. Results obtained with the microscopic framework confirm the correlation of the Δrnp to the isoscalar and isovector GQR energies, as predicted by the macroscopic model. By exploiting this correlation together with the experimental values for the isoscalar and isovector GQR energies, we estimate Δrnp=0.14±0.03 fm for 208Pb, and the slope parameter of the symmetry energy: L=37±18 MeV.
TL;DR: Using a set of model equations of state satisfying the latest constraints from both terrestrial nuclear experiments and astrophysical observations, as well as state-of-the-art nuclear many-body calculations of the pure neutron matter equation of state, the tidal polarizability of canonical neutron stars in coalescing binaries is found to be a very sensitive probe of the high-density behavior of nuclear symmetry energy, which is among the most uncertain properties of dense neutron-rich nucleonic matter as discussed by the authors.
Abstract: Using a set of model equations of state satisfying the latest constraints from both terrestrial nuclear experiments and astrophysical observations, as well as state-of-the-art nuclear many-body calculations of the pure neutron matter equation of state, the tidal polarizability of canonical neutron stars in coalescing binaries is found to be a very sensitive probe of the high-density behavior of nuclear symmetry energy, which is among the most uncertain properties of dense neutron-rich nucleonic matter. Moreover, it changes less than $\ifmmode\pm\else\textpm\fi{}10%$ by varying various properties of symmetric nuclear matter and symmetry energy around the saturation density within their respective ranges of remaining uncertainty.
TL;DR: In this paper, the effects of parton energy loss and pT-broadening in cold nuclear matter on the pT and centrality dependence, at various rapidities, of J/psi suppression in p-A collisions are investigated.
Abstract: The effects of parton energy loss and pT-broadening in cold nuclear matter on the pT and centrality dependence, at various rapidities, of J/psi suppression in p-A collisions are investigated. Calculations are systematically compared to E866 and PHENIX measurements. The very good agreement between the data and the theoretical expectations further supports pT-broadening and the associated medium-induced parton energy loss as dominant effects in J/psi suppression in high-energy p-A collisions. Predictions for J/psi (and Upsilon) suppression in p-Pb collisions at the LHC are given.
TL;DR: In this article, the authors used the energy-dependent waveforms of the X-ray flux oscillations seen during some thermonuclear bursts from some neutron stars to constrain the mass M and radius R of neutron stars.
Abstract: Simultaneous, precise measurements of the mass M and radius R of neutron stars can yield uniquely valuable information about the still uncertain properties of cold matter at several times the density of nuclear matter. One method that could be used to measure M and R is to analyze the energy-dependent waveforms of the X-ray flux oscillations seen during some thermonuclear bursts from some neutron stars. These oscillations are thought to be produced by X-ray emission from hotter regions on the surface of the star that are rotating at or near the spin frequency of the star. Here we explore how well M and R could be determined by generating and analyzing, using Bayesian techniques, synthetic energy-resolved X-ray data that we produce assuming a future space mission having 2-30 keV energy coverage and an effective area of 10 m2, such as the proposed Large Observatory for X-Ray Timing or Advanced X-Ray Timing Array missions. We find that waveforms from hot spots within 10° of the rotation equator usually constrain both M and R with an uncertainty of about 10%, if there are 106 total counts from the spot, whereas waveforms from spots within 20° of the rotation pole provide no useful constraints. The constraints we report can usually be achieved even if the burst oscillations vary with time and data from multiple bursts must be used to obtain 106 counts from the hot spot. This is therefore a promising method to constrain M and R tightly enough to discriminate strongly between competing models of cold, high-density matter.
TL;DR: In this paper, a review of a broad selection of nuclear matter equations of state (EOSs) applicable in core-collapse supernova studies is presented and compared with the classical supernova EOSs.
Abstract: We present a review of a broad selection of nuclear matter equations of state (EOSs) applicable in core-collapse supernova studies. The large variety of nuclear matter properties, such as the symmetry energy, which are covered by these EOSs leads to distinct outcomes in supernova simulations. Many of the currently used EOS models can be ruled out by nuclear experiments, nuclear many-body calculations, and observations of neutron stars. In particular the two classical supernova EOS describe neutron matter poorly. Nevertheless, we explore their impact in supernova simulations since they are commonly used in astrophysics. They serve as extremely soft and stiff representative nuclear models. The corresponding supernova simulations represent two extreme cases, e.g., with respect to the protoneutron star (PNS) compactness and shock evolution. Moreover, in multi-dimensional supernova simulations EOS differences have a strong effect on the explosion dynamics. Because of the extreme behaviors of the classical supernova EOSs we also include DD2, a relativistic mean field EOS with density-dependent couplings, which is in satisfactory agreement with many current nuclear and observational constraints. This is the first time that DD2 is applied to supernova simulations and compared with the classical supernova EOS. We find that the overall behaviour of the latter EOS in supernova simulations lies in between the two extreme classical EOSs. As pointed out in previous studies, we confirm the impact of the symmetry energy on the electron fraction. Furthermore, we find that the symmetry energy becomes less important during the post bounce evolution, where conversely the symmetric part of the EOS becomes increasingly dominating, which is related to the high temperatures obtained. Moreover, we study the possible impact of quark matter at high densities and light nuclear clusters at low and intermediate dens
TL;DR: In this paper, the effect of the three-body forces on the total energy, computed with an extended Galitskii-Migdal-Koltun sum-rule, was discussed.
Abstract: We present calculations for symmetric nuclear matter using chiral nuclear interactions within the self-consistent Green's functions approach in the ladder approximation. Three-body forces are included via effective one-body and two-body interactions, computed from an uncorrelated average over a third particle. We discuss the effect of the three-body forces on the total energy, computed with an extended Galitskii-Migdal-Koltun sum-rule, as well as on single-particle properties. Saturation properties are substantially improved when three-body forces are included, but there is still some underlying dependence on the similarity renormalization group evolution scale.
TL;DR: Property of doubly magic nuclei are used to constrain symmetric nuclear matter and neutron matter equations of state to determine the value of the neutron equation of state at a density of ρ(on)=0.10 nucleons/fm3 to be 11.4(10) MeV.
Abstract: I use properties of doubly magic nuclei to constrain symmetric nuclear matter and neutron matter equations of state. I conclude that these data determine the value of the neutron equation of state at a density of ${\ensuremath{\rho}}_{on}=0.10\text{ }\text{ }\mathrm{nucleons}/{\mathrm{fm}}^{3}$ to be 11.4(10) MeV. The slope at that point is constrained by the value of the neutron skin. Analytical equations are given that show the dependence of the Skyrme equations of state on the neutron skin.
TL;DR: This work studies 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.
Abstract: Lattice QCD at finite density suffers from a severe sign problem, which hasso far prohibited simulations of the cold and dense regime. Here we study theonset of nuclear matter employing a three-dimensional effective theory derivedby combined strong coupling and hopping expansions, which is valid for heavybut dynamical quarks and has a mild sign problem only. Its numericalevaluations agree between a standard Metropolis and complex Langevin algorithm,where the latter is free of the sign problem. Our continuum extrapolated dataclearly show a first order phase transition building up at $\mu_B \approx m_B$as the temperature approaches zero. An excellent description of the data isachieved by an analytic solution in the strong coupling limit.
TL;DR: In this paper, the effects of parton energy loss and broadening in cold nuclear matter on the suppression of high-energy p-A collisions were investigated, and the very good agreement between the data and the theoretical expectations further supports p�-broadening and the associated medium-induced parton EE loss as dominant effects in J/ψ suppression in high energy p-Pb collisions at the LHC.
Abstract: The effects of parton energy loss and p
⊥-broadening in cold nuclear matter on the p
⊥ and centrality dependence, at various rapidities, of J/ψ suppression in p-A collisions are investigated. Calculations are systematically compared to E866 and PHENIX measurements. The very good agreement between the data and the theoretical expectations further supports p
⊥-broadening and the associated medium-induced parton energy loss as dominant effects in J/ψ suppression in high-energy p-A collisions. Predictions for J/ψ (and $ \varUpsilon $
) suppression in p-Pb collisions at the LHC are given.
TL;DR: In this paper, a self-consistent nuclear density functional theory (DFT) with Skyrme energy density functionals and covariance analysis was used to assess correlations between observables for finite nuclei and neutron stars.
Abstract: Background: Recent observational data on neutron star masses and radii provide stringent constraints on the equation of state of neutron rich matter [Annu. Rev. Nucl. Part. Sci. 62, 485 (2012)].Purpose: We aim to develop a nuclear energy density functional that can be simultaneously applied to finite nuclei and neutron stars.Methods: We use the self-consistent nuclear density functional theory (DFT) with Skyrme energy density functionals and covariance analysis to assess correlations between observables for finite nuclei and neutron stars. In a first step two energy functionals---a high density energy functional giving reasonable neutron properties, and a low density functional fitted to nuclear properties---are matched. In a second step, we optimize a new functional using exactly the same protocol as in earlier studies pertaining to nuclei but now including neutron star data. This allows direct comparisons of performance of the new functional relative to the standard one.Results: The new functional TOV-min yields results for nuclear bulk properties (energy, rms radius, diffraction radius, and surface thickness) that are of the same quality as those obtained with the established Skyrme functionals, including SV-min. When comparing SV-min and TOV-min, isoscalar nuclear matter indicators vary slightly while isovector properties are changed considerably. We discuss neutron skins, dipole polarizability, separation energies of the heaviest elements, and proton and neutron drip lines. We confirm a correlation between the neutron skin of ${}^{208}$Pb and the neutron star radius.Conclusions: We demonstrate that standard energy density functionals optimized to nuclear data do not carry information on the expected maximum neutron star mass, and that predictions can only be made within an extremely broad uncertainty band. For atomic nuclei, the new functional TOV-min performs at least as well as the standard nuclear functionals, but it also reproduces expected neutron star data within assumed error bands. This functional is expected to yield more reliable predictions in the region of very neutron rich heavy nuclei.