Showing papers on "Nuclear matter published in 1971"
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TL;DR: In this article, the authors describe the energy of nuclei in the free neutron regime by a compressible liquid-drop model designed to take into account three important features: (i) as the density increases, the bulk nuclear matter inside the nuclei, and the pure neutron gas outside the nucleus become more and more alike; and (ii) the presence of the neutron gas reduces the nuclear surface energy.
589 citations
TL;DR: In this paper, the energy of the neutron gas is studied with the Reid and Bressel-Kerman-Rouben soft core potentials up to a density of 4.5 neutrons fm 3, and very approximate estimates for neutron gas and solid energies are presented also for the Hamada-Johnston hard core potential.
146 citations
132 citations
TL;DR: In this paper, the optical potential for pions propagating in nuclear matter is investigated from a many-body point of view, and an exact expression for the pion-nucleon correlation function is obtained in terms of the nuclear matter density-density correlation function.
102 citations
TL;DR: In this paper, a local effective interaction that reproduces the G-matrix elements from an infinite nuclear matter calculation using the Reid potential is constructed, which is suitable for finite nucleus Hartree-Fock studies in the local density approximation, where sensitivity to the above listed properties can be studied systematically.
93 citations
TL;DR: In this paper, the energy shift associated with the normal-to-superfluid state transition induced by S-wave pairing is estimated by a variational method, with trial superfluid-state and reference normal-state wave functions incorporating strong short-range correlations.
58 citations
TL;DR: The contribution of the two-pion exchange three-body force to the binding energy of nuclear matter was examined in this paper, and cutoffs between all the pairs of nucle´ons were introduced.
58 citations
TL;DR: In this paper, the free reaction matrix R and the Brueckner-Goldstone reaction matrix G were used to solve the two-nucleon scattering and nuclear matter problem in the helicity state formalism.
50 citations
47 citations
TL;DR: In this paper, the effects of nuclear structure on high-energy coherent reactions were investigated and a multiple scattering description of elastic coherent processes in the presence of nuclear correlations was presented and generalized to inelastic coherent processes, including the extra phase associated with the mass change of the projectile in diffractive production.
TL;DR: In this article, the effect of coupling of the ΛN to the (virtual) ∑N channel on the ǫ-particle binding in nuclear matter (the Λ-well depth) is studied with perturbation theory and especially in the reaction-matrix approach with use of the g -matrix approximation.
TL;DR: In this paper, the binding energy of nuclear matter was examined for exactly phase-shift-equivalent potentials, and it was shown that variations of up to 9.5 MeV and 0.33 F in the saturation density occur.
Abstract: We examine the binding energy of nuclear matter for exactly phase-shift-equivalent potentials. We generate these potentials by applying a short-range unitary transformation to the Reid soft-core potential. All potentials have a one-pion-exchange tail. We find that, for the potentials studied, variations of up to 9.5 MeV in the binding energy and 0.33 F in the saturation density occur. The variations in binding energy Are linearly correlated with the wound integral K for those potentials that give nearly the same deuteron electric form factor. An increase in K leads to less binding in nuclear matter. The sensitivity of the binding energy is somewhat greater to the S&+ D& contribution to K than to the So contribution to K. We give a theoretical explanation, based on the modified Moszkowski-Scott separation approximation, to account for the sensitivity of the binding energy to the So and S&+ D& contributions to K. We also discuss the relation of K and the binding energy of nuclear matter to the off-shell elements of the T matrix. We discover that far-off-shell elements (q 6 F ) play a significant role in nuclear matter. The two-nucleon elastic scattering data and certain bound-state properties provide the only direct experimental criteria one can apply to the two-nucleon interaction. The scattering data only fix the asymptotic form of the two-nucleon wave function; the wave function at short distances, aside from meson-theoretic constraints, ' ' is undetermined. Equivalently, the scattering data determine the onenergy-shell matrix elements of the transition (T) matrix; the off-energy-shell T matrix is undetermined by the two-nucleon data. The question arises — how sensitive are the properties of three- and more-nucleon systems to the short-range part of the two-nucleon wave function or to the off-energyshell T matrix~ This paper considers this question for infinite nuclear matter. The investigation of off-shell effects in nuclear matter is especially important in view of the disagreement between the binding energies obtained from "realistic" local potentials (10 to ll MeV/A) ' 8 and the semiempirical mass formula prediction of 16 MeV/A. Recently a number of investigators have studied off-shell effects in proton-proton bremsstrahlung. ' The results of these studies indicate only small off-energy-shell effects. Investigations into the off-shell effects in the three-nucleon boundstate problem are still in the preliminary stages. "" On the other hand, several investigators''3' " have suggested that off-shell effects in
TL;DR: One-term separable potentials in the 3S-3D channel are constructed in this article which fit the following low-energy nucleon-nucleon data: the triplet effective range and scattering length, deuteron binding energy and quadrupole moment.
TL;DR: In this paper, an empirical approach based on scaling the properties of helium and other substances with a corresponding states argument was adopted to predict a solidification pressure for neutron matter and suggest modifications to the equation of state.
Abstract: LITTLE attention seems to have been paid to the possibility of a neutron solid—a solid lattice of neutrons—or to consideration of the density regime in which it might exist. A useful theoretical calculation would be prohibitively complicated, so we have adopted an empirical approach based on scaling the properties of helium and other substances with a corresponding states argument. We are able to predict a solidification pressure for neutron matter and suggest modifications to the equation of state.
TL;DR: In this article, the average nuclear-binding energy surface on the Z-plane was calculated using Brueckner et al.'s energy-density functional, which was used to calculate the average binding energy surface.
Abstract: The energy-density functional proposed by Brueckner etal. is used to calculate the average nuclear-binding-energy surface on the $N\ensuremath{-}Z$ plane at $\ensuremath{\beta}$ stability \ifmmode\pm\else\textpm\fi{} about 40 units. The equibinding contours are compared with those predicted by recent liquid-droplet models. Normally, some disagreement begins about 15 units away from the region of known nuclei. The deviations towards lower binding are significant for neutron-rich transuranium (superheavy) nuclei. This would seem to indicate a physically important uncertainty in conventional masslaw extrapolations. The semiempirical dependence on neutron excess cannot be established very well, because of the narrowness of the region of known isotopes. The energy-density functional, on the other hand, incorporates the present knowledge about nuclear matter - including recent neutron-matter results. Our disagreement with other extrapolations, therefore, questions the validity of stability and formation (e.g., $r$-process) calculations based on conventional mass formulas.
TL;DR: In this article, the authors measured the angular distribution of 16 MeV protons elastically scattered from isotopes of tin and used the optical-model analysis combined with existing data on charge radii yielded a separation between neutron and proton rms radius of about 0.5 fm.
TL;DR: Inelastic transition form factors for alpha-nucleus collective excitations are derived from deformed matter distributions by averaging an effective alpha nucleus interaction over the nucleons in the nucleus as mentioned in this paper.
TL;DR: In this paper, a simple microscopic model is used to compare this formalism with an alternative formation based on a deformed nuclear density, and it is concluded that the accepted collective inelastic formalism may be totally fallacious and that any agreement between its predictions and experiment is perhaps fortuitious.
TL;DR: In this article, the binding energy of a Λ-particle in a potential well representing a heavy hypernucleus is considered and the exact solution of the Schrodinger equation with a potential of a Fermi (Saxon-Woods) shape is obtained.
TL;DR: The binding energy of the neutron gas is calculated in Brueckner theory with Ingber's potential which is derived from meson theory as mentioned in this paper, and the resulting equation of state is used to calculate the structure of neutron stars with central densities up to 10 15 g/cm 3.
TL;DR: The binding energy and saturation density of nuclear matter have been calculated for our momentum dependent OBEP by the reference spectrum method of Bethe et al. as mentioned in this paper, and a binding energy of −11.2 MeV per particle was found at a density corresponding to the Fermi momentum kF = 1.55 fm−1.
TL;DR: In this article, the choice of the potential energy U for hole states in a Bethe-Brueckner calculation of nuclear matter is discussed and a cancellation is found between the U-dependence of the two-hole and three-hole line contributions.
TL;DR: In this article, the statistical method suggested by Brueckner et al. is applied to the system of semi-infinite nuclear matter to study the nuclear surface properties, and an approximate estimation of the value of the nuclear compressibility is given.
TL;DR: Inelastic scattering of 30.3 MeV polarized protons is analyzed using an extension of the folding procedure recently applied to elastic scattering analysis in this article, and the resulting fits are in general better than those achieved with the standard coupled-channels procedure.
TL;DR: In this article, a model space is introduced to take especial care of the contribution of low-lying states to f(k1, k2) for nuclear matter, and a simple perturbative approach is attempted within the model space.
TL;DR: In this paper, the authors investigated the contribution of three-body forces to the binding energy of nuclear matter, including the effects of two-body correlations induced by the two-nucleon forces.
Abstract: We investigate the contribution of three-body forces to the binding energy of nuclear matter, including the effects of two- and three-body correlations induced by the two-nucleon forces, and find that it may by approximated using plane-wave three-nucleon states cut off when any interparticle distance is less than about 0.9 fm. Existing calculations can then be used to estimate that three-body forces contribute about 1 MeV to the binding energy.
TL;DR: In this article, the binding energy of triton with different potentials and high-energy phase shifts was shown to be independent of the high energy phase shift of the triton.
TL;DR: In this paper, the Bethe-Faddeev three-body energy is recalculated for two different single-particle potentials, one of which is attractive for small particle-state momenta.