A recently proposed baryon mapping of colorless three-quark clusters is applied to a three-color delta model in the infinite nuclear matter limit, to assess its usefulness in the presence of spatial three-quark correlations. Treating the resulting baryon Hamiltonian in Hartree-Fock approximation exactly reproduces the energy per quark of the model through second order in the density. Deviations show up in higher orders, however, most likely reflecting the need for an improved description of the short-range repulsion between baryons beyond that of the Hartree-Fock approximation.

We study, in the framework of a QCD-inspired confining Nambu–Jona-Lasinio model, the I=1;0, S-wave K-N phase shifts for simple examples of chirally consistent microscopic potentials. The Dyson equation for the scattering of the bound states K and N is solved. The equivalence between this equation and the resonating group method equation is presented. The role of the chiral symmetry in the strength of the effective hyperfine potential, simultaneously responsible for the features of K-N repulsion and the π-ρ mass difference, is discussed.

We use classical/large ${\mathit{N}}_{\mathit{C}}$ (number of colors) QCD to study nucleon-antinucleon annihilation at rest. We include pion, ρ, and ω fields in the classical dynamics, starting from the nonlinear sigma model. We begin with a spherical blob of pionic matter with zero baryon number and energy of twice the nucleon mass. This evolves according to the classical dynamics to pion and vector meson fields into the radiation zone. The radiation fields are quantized using the method of coherent states modified to include isospin and four momentum conservation. Empirical information is extracted from that coherent state. We find good agreement with data for single particle momentum and number spectra, and with branching ratios to many annihilation channels. All this emerges with nearly no free parameters.

A calculation of the pion radius to O(1/${\mathit{N}}_{\mathit{c}}$) in the Nambu–Jona-Lasinio model indicates that the chiral logarithmic term of chiral perturbation theory (CHPT) is recovered from the higher order corrections in the static limit in the Pauli-Villars regularization scheme, and with Λ→∞. This follows equivalently in the O(3) scheme under the assumption that Λ≫m. The chiral logarithm is the leading contribution in the chiral limit. However, at the physical values of the current quark mass, the constant term due to the intrinsic structure of the pion plays the key role. This intrinsic term is the usual term that arises from the photon coupling to the internal quark and antiquark structure that makes up the pion, and corresponds to the tree level calculation in CHPT. At physical values of the current quark masses, it turns out that this term is the leading one, with the chiral logarithmic term being subleading. From the values obtained for 〈${\mathit{r}}_{\mathrm{\pi }}^2$〉, we can also set an upper limit for the contribution expected from the ρ meson. This is determined as 〈${\mathit{r}}_{\mathrm{\pi }}^2$${\mathrm{〉}}_{\mathrm{\rho }}$<(0.4) ${\mathrm{fm}}^2$. A redetermination of l${\mathrm{¯}}_6$ including the higher order contribution gives l${\mathrm{¯}}_6$=16.07. The finite temperature dependence of the mean square charge radius is also examined, and its behavior is determined principally by the intrinsic part.

We evaluate the S-wave pion-nucleon scattering length ${\mathit{a}}^{\mathrm{-}}$ in the framework of heavy baryon chiral perturbation theory up-to-and-including terms of order ${\mathit{M}}_{\mathrm{\pi }}^4$. We show that the order ${\mathit{M}}_{\mathrm{\pi }}^4$ piece of the isovector amplitude at threshold, ${\mathit{T}}_{\mathrm{thr}}^{\mathrm{-}}$, vanishes exactly. We predict for the isovector scattering length, 0.088${\mathit{M}}_{{\mathrm{\pi }}^{+}}^{\mathrm{-}1}$≤${\mathit{a}}^{\mathrm{-}}$≤0.096${\mathit{M}}_{{\mathrm{\pi }}^{+}}^{\mathrm{-}1}$.

The S-wave scattering length for the ηN elastic scattering is extracted from the S-wave T matrix in a three-coupled-channel, multiresonance unitary model. Results are compared with values already reported in the literature which are obtained on the basis of simpler models, usually single-resonance–no background. The dispersion among the previously published values of the real part of the S-wave scattering length is observed. We show that the ηN scattering length value obtained in single-resonance–no background models significantly increases if a background term is added in a unitary way. We question the reliability of previously reported values based only on the single-resonance–no background models, and demonstrate that the value of the ηN S-wave scattering length obtained in this publication is much more realistic because of the multiresonance and unitary approach.

We investigate the properties of quark matter at finite density and temperature using the nonlinear chiral extension of the color dielectric model. Assuming that the square of the meson fields develops a nonzero vacuum expectation value, the thermodynamic potential for interacting three flavor matter has been calculated. It is found that 〈${\mathit{K}}^2$〉 and 〈${\mathrm{\eta }}^2$〉 remain zero in the medium whereas 〈${\mathrm{\pi }}^2$〉 changes in the medium. As a result, u and d quark masses decrease monotonically as the temperature and density of the quark matter is increased. In the present model, the deconfinement density and temperature are found to be lower compared to lattice results. We also study the behavior of pressure and energy density above critical temperature.

Some low energy neutrino nucleus reactions induced by neutrinos (antineutrinos) having a magnetic moment of the order of ${10}^{\mathrm{-}9}$-${10}^{\mathrm{-}10}$ Bohr magneton are studied. It is found that in the case of ${}_{}{}^4{}_{}{}^{}\mathrm{He}$, ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$, and ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$, the detection of very low energy scalar and isoscalar elastic and inelastic reactions induced by the isoscalar vector currents can provide a better limit on the neutrino magnetic moment.

The ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$(p,n${)}^{20}$Na reaction at 135 MeV was studied experimentally using the beam-swinger neutron time-of-flight facility at the Indiana University Cyclotron Facility. Backgrounds ∼10× lower than an earlier experiment were obtained using the ‘‘stripper loop’’ storage ring to achieve ∼2 μs between beam bursts. We were able to see a weakly excited state at 2.65 MeV in ${}_{}{}^{20}{}_{}{}^{}\mathrm{Na}$ with a Δl=2 angular distribution. The angular distribution is consistent with a DWIA calculation assuming a $3^{+}$ final state. The characteristics of this state are important to know for considerations of possible breakout in the hot CNO cycle in supernovae explosions.

We calculate spin-dependent cross sections for the scattering from mica of hypothetical weakly interacting dark-matter particles such as neutralinos. The most abundant odd-A isotopes in mica, ${}_{}{}^{27}{}_{}{}^{}\mathrm{Al}$ and ${}_{}{}^{39}{}_{}{}^{}\mathrm{K}$, require different shell-model treatments. The calculated cross sections will allow the interpretation of ongoing experiments that look for tracks due to the interaction of dark-matter particles with nuclei in ancient mica.

The production of positive pions and neutrons by cosmic muons at underground sites of various depths is investigated. We first test the equivalent photon method in the particular case of Δ excitation by the muon. We find that this method, when it neglects the momentum dependence of the transverse response, reproduces remarkably well the theoretical muon cross section. This success has lead us to apply the method to higher energies, where it has not been tested. We evaluate in this way the production of positive pions in liquid scintillator from known photo-absorption cross sections. At a shallow depth of 20 meters our estimate reproduces the measurement. As for the neutron emission, we include the obvious sources, such as the giant-resonance excitation, the quasideuteron process, the quasifree pion production as well as neutrons emitted following pion capture. Our evaluation underestimates the number of neutrons produced and finds a too weak dependence on the depth. This suggests that secondary neutron production is important at all depths.

Recent calculations suggest that the neutrino heated bubbles in the postcollapse phase of type II supernovae may be the site of the r process. The nucleosynthesis process depends on the expansion and cooling rates as well as on the rates of the α-particle and neutron recombination processes that bridge the mass gaps at A = 5 and 8. We have reexamined the rate for the important reaction ${}_{}{}^4{}_{}{}^{}\mathrm{He}$(αn,γ${)}^9$Be, and estimated the rates for the two neutron capture reactions on ${}_{}{}^6{}_{}{}^{}\mathrm{He}$ and ${}_{}{}^8{}_{}{}^{}\mathrm{He}$ which could provide an alternative reaction path. We find that the most important reaction for initiating the α process is the ${}_{}{}^4{}_{}{}^{}\mathrm{He}$(αn,γ${)}^9$Be reaction, as suggested by earlier work.

The α and β decays of ${}_{}{}^{160–162}{}_{}{}^{}\mathrm{Hf}$ were measured following their productions in ${}_{}{}^{135}{}_{}{}^{}\mathrm{Ba}$${(}^{32}$S, xn) reactions. For the first time γ transitions following ${}_{}{}^{160}{}_{}{}^{}\mathrm{Hf}$ β decay were observed. Partial β-decay schemes of ${}_{}{}^{161,162}{}_{}{}^{}\mathrm{Hf}$ are presented and the α decay rates of ${}_{}{}^{160}{}_{}{}^{}\mathrm{Hf}$ and ${}_{}{}^{162}{}_{}{}^{}\mathrm{Hf}$ are discussed within the systematics of $0^{+}$→$0^{+}$ α reduced widths.

The half-lives of the 14.4 keV isomeric state in ${}_{}{}^{57}{}_{}{}^{}\mathrm{Fe}$ and the 9.4 keV isomeric state in ${}_{}{}^{83}{}_{}{}^{}\mathrm{Kr}$ have been accurately measured using electronic timing. The two isomers were populated in the electron capture decays of ${}_{}{}^{57}{}_{}{}^{}\mathrm{Co}$ and ${}_{}{}^{83}{}_{}{}^{}\mathrm{Rb}$, and the time distributions between γ-γ cascades proceeding via the isomers were determined. Results are 99.2(4) and 155.1(12) ns for the ${}_{}{}^{57}{}_{}{}^{}\mathrm{Fe}$ and ${}_{}{}^{83}{}_{}{}^{}\mathrm{Kr}$ states respectively.

We present systematic constrained Hartree-Fock calculations of ground-state properties of even strontium isotopes (A=76–100) with the Skyrme interaction. Approximate projection of angular momentum is done after variation by explicit inclusion of the rotational energy -〈j${\mathrm{^}}_{\mathit{x}}^2$〉/J. This procedure allows for the determination of the ground-state deformations as well as the low rotational states. The binding energies, rms radii, quadrupole moments, and rotational states are discussed.

We reexamine Chew’s method for extracting the πNN coupling constant from np differential cross section measurements. Values for this coupling are extracted below 350 MeV, in the potential model region, and up to 1 GeV. The analyses to 1 GeV have utilized 55 data sets. We compare these results to those obtained via ${\mathrm{\chi }}^2$ mapping techniques. We find that these two methods give consistent results which are in agreement with previous Nijmegen determinations.

We calculate that the geometrical structure of the crystalline solid mixed phase of confined-deconfined hadronic matter in neutron stars—its form, size, spacing, and location in the star—is highly individualistic according to small changes in the stellar mass. This suggests a possible connection with the wide range of glitch behavior observed in different pulsars, since glitches are almost certainly associated with solid regions.

The data fits of microscopic nuclear mass formulas can be considerably improved by making the pairing force slightly stronger for an odd number of like nucleons than for an even number. Qualitatively at least, such an effect could arise from the fact that the Hartree-Fock wave function of an odd nucleus is not an eigenstate of the time-reversal operator.

The proton escape widths of the isobaric analog state and the Gamow-Teller resonance in ${}_{}{}^{208}{}_{}{}^{}\mathrm{Bi}$ are calculated by solving the charge-exchange continuum Tamm-Dancoff equations. For the Gamow-Teller resonance the spreading contribution to the width is taken into account by the imaginary part of the optical potential. The calculated escape widths are in agreement with measurements obtained from a recent ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$${(}^3$He,tp${)}^{208}$Bi experiment.

Energy differences between 1d5/2 and 2s1/2 states in light nuclei are reviewed and systematized. A simple model accounts for the Coulomb shifts.