We compare the use of asymptotic normalization coefficients (ANC’s) and spectroscopic factors determined from peripheral transfer reactions for determining the overall normalization of peripheral direct radiative capture reaction processes. We demonstrate that ANC’s provide a natural way to parametrize the rates of both peripheral transfer and direct capture reactions. Furthermore, ANC’s inferred from one reaction may be used in the analysis of a second reaction without further knowledge regarding their origin, and independent measurements of a given ANC may be combined to give an overall “best value” in a straightforward manner. In contrast, a spectroscopic factor derived from analysis of a peripheral transfer reaction can only be used in subsequent calculations if one has detailed knowledge of the single-particle bound state orbital that was assumed when the spectroscopic factor was obtained.

We develop and extend the dynamical string parton model. This model, which is based on the salient features of QCD, uses classical Nambu-Gotō strings with the endpoints identified as partons, an invariant string breaking model of the hadronization process, and interactions described as quark-quark interactions. In this work, the original model is extended to include a phenomenological quantization of the mass of the strings, an analytical technique for treating the incident nucleons as a distribution of string configurations determined by the experimentally measured structure function, the inclusion of the gluonic content of the nucleon through the introduction of purely gluonic strings, and the use of a hard parton-parton interaction taken from perturbative QCD combined with a phenomenological soft interaction. The limited number of parameters in the model are adjusted to $e^{+}{e}^{-}$ and $p–p$ data. Utilizing these parameters, the first calculations of the model for $p–A$ and $A–A$ collisions are presented and found to be in reasonable agreement with a broad set of data.

A nonlinear chiral SU(3) approach including the spin-$\frac{3}{2}$ decuplet is developed to describe dense matter. The coupling constants of the baryon resonances to the scalar mesons are determined from the decuplet vacuum masses and SU(3) symmetry relations. Different methods of mass generation show significant differences in the properties of the spin-$\frac{3}{2}$ particles and in the nuclear equation of state.

In this paper we propose a formalism to remove the center of mass motion of the relativistic three-quark system in order to calculate not only one-body operators, but also two-body interactions. We employ various methods used in the past to remove the center of mass motion. We then calculate the masses of the nucleon and Δ resonance with residual one-gluon, sigma meson, and pseudoscalar pion and eta meson exchange potentials. Magnetic moments, root mean square radii, pion-nucleon coupling constant, and the axial vector coupling constant are also calculated. The main purpose of the calculation is to study the effect of the removal of the center of mass motion and investigate the similarities and differences between a relativistic and nonrelativistic description of constituent quarks. The method projecting onto the total momentum $P=0,$ is found to give results consistent with experiments. It is also found that light quark mass and strong confinement are appropriate to reproduce the nucleon and Δ masses in the relativistic approach.

We calculate the pion’s valence-quark momentum-fraction probability distribution using a Dyson-Schwinger equation model. Valence quarks with an active mass of 0.30 GeV carry 71% of the pion’s momentum at a resolving scale $q_0=0.54\mathrm{}\hspace{0.5em}\mathrm{GeV}=1/\left(0.37\mathrm{}\hspace{0.5em}\mathrm{fm}\right).\mathrm{}$ The shape of the calculated distribution is characteristic of a strongly bound system and, evolved from $q_0$ to $q=2\mathrm{}\hspace{0.5em}\mathrm{GeV},$ it yields first, second, and third moments in agreement with lattice and phenomenological estimates, and valence-quarks carrying 49% of the pion’s momentum. However, pointwise there is a discrepancy between our calculated distribution and that hitherto inferred from parametrizations of extant pion-nucleon Drell-Yan data.

The importance of geometrical effects in the A dependence of many observables regarding antiproton annihilation on nuclei is expected on theoretical grounds. The cases of the charged pion multiplicity and of the frequency of the so-called single nucleon events are examined. In the first case, the respective roles of surface diffuseness, partial nuclear opacity, and pion absorption mechanism are examined. The possibility of extracting from comparison with experiment the average location of the annihilation site is critically discussed. The obtained values are in agreement with current theoretical estimates.

Direct γ and electronic-bridge (EB) decay modes of the low-energy isomeric level ${}^{229}{\mathrm{Th}}^m$ are compared theoretically and it is found that the decay rates for the two channels are approximately equal. Our findings disagree with those of a recent theoretical paper, where it was found that deexcitation happens mainly through the EB process. Recent experimental results also mandate a reinterpretation of previous data and suggest, in particular, that no unambigous evidence of the isomeric decay has been seen in previous experiments since luminescence due to α decay may have concealed the effect. Therefore an optical method for the demonstration of existence and the determination of energy separation of these nearby-lying nuclear states is proposed again.

The level density at low spin in the ${}^{161,162}\mathrm{Dy}$ and ${}^{171,172}\mathrm{Yb}$ nuclei has been extracted from primary γ rays. The nuclear heat capacity is deduced within the framework of the canonical ensemble. The heat capacity exhibits an S-formed shape as a function of temperature, which is interpreted as a fingerprint of the phase transition from a strongly correlated to an uncorrelated phase. The critical temperature for the quenching of pair correlations is found at $T_c=0.50\mathrm{}\pm 0.04\left(\mathrm{stat}\right)\pm 0.08\left(\mathrm{syst}\right)\hspace{0.5em}\mathrm{MeV}.$

Binding energies, quadrupole deformation parameters, spins, and parities of the neutron-deficient odd $Z=N+1\mathrm{}$ nuclei in the $A\sim 80$ region are calculated in the relativistic mean field approximation. The ground-state and low-lying configurations of the recently observed ${}^{77}\mathrm{Y},$ ${}^{79}\mathrm{Zr},$ and ${}^{83}\mathrm{Mo}$ nuclei are analyzed. The calculated results are compared with other theoretical predictions.

Hartree-Fock binding and single-proton energies are calculated including the exact Coulomb exchange with the Skyrme SkP and SkM* forces for a number of spherical nuclei up to the expected superheavy species. Results are presented as corrections to the standard Slater approximation. They turn out nearly force-independent. Their magnitude and influence on selected features of nuclear structure are discussed.

The importance of a Coulomb correction to the formalism proposed by Albergo et al. for determining the temperatures of nuclear systems at breakup and the densities of free nucleon gases is dicussed. While the proposed correction has no effect on the temperatures extracted based on double isotope ratios, it becomes non-negligible when such temperatures or densities of free nucleon gases are extracted based on multiplicities of heavier fragments of different atomic numbers.

A semimicroscopic, Lane-consistent optical model is established up to 200 MeV for nucleons incident on spherical and near-spherical nuclei with masses $40<~A<~209.$ This model, based on the earlier approach of Jeukenne, Lejeune, and Mahaux in nuclear matter, is an extension of our previous work [E. Bauge, J. P. Delaroche, and M. Girod, Phys. Rev. C 58, 1118 (1998)]. The modulus of the isovector potential is extracted and compared with measurements and fully microscopic predictions. Good overall descriptions of nucleon scattering, of transitions to isobaric analog states, and of reaction observables are obtained down to 1 keV. Those results are discussed in detail.

In this paper, we present differential cross sections and complete sets of polarization transfer coefficients, $D_{\mathrm{ij}},$ obtained in the ${}^{13}\mathrm{C}(\overrightarrow{p},\overrightarrow{n}{)}^{13}\mathrm{N}$ reaction studied at zero degree and at 197 MeV incident proton energy. The complete set of polarization observables is used to obtain the Fermi and Gamow-Teller (GT) cross section contributions in the ground state transition, which are then used to deduce GT transition strengths. The sum of the GT strength up to 20 MeV of excitation is compared with shell model calculations. In the region between 20 to 46 MeV of excitation, the differential cross section has been separated in spin and nonspin components.

The initial distribution of gluons at the very early times after a high-energy heavy ion collision is described by the bulk scale $Q_s$ of gluon saturation in the nuclear wave function. The subsequent evolution of the system towards kinetic equilibrium is described by a nonlinear Landau equation for the single particle distributions [A. H. Mueller, Nucl. Phys. B572, 227 (2000); Phys. Lett. B 475, 220 (2000)]. In this paper, we solve this equation numerically for the idealized initial conditions proposed by Mueller, and study the evolution of the system to equilibrium. We discuss the sensitivity of our results on the dynamical screening of collinear divergences. In a particular model of dynamical screening, the convergence to the hydrodynamic limit is seen to be rapid relative to hydrodynamic time scales. The equilibration time, the initial temperature, and the chemical potential are shown to have a strong functional dependence on the initial gluon saturation scale $Q_s.$

Quantities that determine the structure of the continuum part of nuclear spectra are studied in detail. Measurable particle (proton) decay processes are discussed and formulas to evaluate the corresponding decay widths are analyzed. It is shown that the decaying resonances are so narrow that such processes can be treated as if the nucleus was bound and, therefore, they are not suitable to probe formalisms designed to treat the continuum. Other processes that are more sensitive to broad resonances are analyzed and suggestions for probable experiments are made.

Using a coherence time extracted from high precision proton-nucleus Drell-Yan measurements and a nuclear absorption cross section extracted from pA charmonium production experiments, we study J/ψ production and absorption in nucleus-nucleus collisions. We find that coherence time effects are large enough to affect the measured J/ψ–to–Drell-Yan ratio. The $\mathrm{S}+\mathrm{U}$ data at $200A\mathrm{GeV}/c$ measured by NA38 are reproduced quantitatively without the introduction of any new parameters. However, when compared with recent NA50 measurements for $\mathrm{Pb}+\mathrm{Pb}$ at $158A\hspace{0.5em}\mathrm{GeV}/c,$ the data is not reproduced in trend or in magnitude.

Identity relations among the transverse parts of variant vertex functions in gauge theories are derived by computing the curl of the time-ordered products of three-point Green’s functions involving the vector, the axial-vector, and the tensor current operators, respectively. Combining these transverse relations with the normal (longitudinal) Ward-Takahashi identities forms a complete set of Ward-Takahashi relations for three-point vertex functions. As a consequence, the complete solutions for the vector, the axial-vector, and the tensor vertex functions in the momentum space are consistently and exactly obtained by solving this complete set of Ward-Takahashi relations. In the case of massless fermions, the full vector and the full axial-vector vertices are expressed in terms of the fermion propagators only.

We show that the model which naturally explains the $ū\ne \overline{d}$ asymmetry in the nucleon and is in quantitative agreement with the Gottfried sum rule data, also predicts that in the proton $\Delta ū>0>\Delta \overline{s}>\Delta \overline{d}$ and $\Delta ū-\Delta \overline{d}>\overline{d}-ū>0.\mathrm{}$ At the input scale, these results can be derived even analytically. Thus the violation of the flavor symmetry is more serious in the polarized case than in the unpolarized case. In contrast, many recent analyses of the polarized data have made a simplifying assumption that all the three $\Delta \overline{q}’\mathrm{s}$ have the same sign and magnitude. We point out the need to redo these analyses, allowing for the alternate scenario as described above. We present predictions of the model for the $W^{-}$ asymmetry in polarized $\mathrm{pp}$ scattering, which can be tested at RHIC; these are quite different from those available in the literature.

In this work we demonstrate the range of application of our generalized Nambu–Jona-Lasinio (NJL) model. We discuss the scalar-isoscalar mesons that are thought to have a $q\overline{q}$ structure and also consider some properties of nuclear matter. The spectrum of scalar-isoscalar mesons provides some insight into the sigma models that may be used to describe the dynamics of pseudoscalar and scalar mesons. Some authors have suggested that the lowest $q\overline{q}\hspace{0.5em}{0}^{++}$ state is the $f_0\mathrm{}\left(1370\right).$ [The $f_0(400\mathrm{}–1200)$ that now appears in the data tables may be generated dynamically in π-π scattering and is not a “preexisting” state of the spectrum.] The $f_0\mathrm{}\left(980\right)\mathrm{}$ and $a_0\mathrm{}\left(980\right)\mathrm{}$ are often designated as $K-\overline{K}$ molecules. However, recent work does not support that assignment. Since there is no low-lying scalar state, the model of choice in describing pseudoscalar meson dynamics is the nonlinear sigma model. However, there are a number of applications of the Nambu–Jona-Lasinio model in the study of nuclear matter properties that can be described in terms of the linear sigma model. In the linear sigma model there is a low-mass σ meson, whose effects would be generated dynamically in the nonlinear model. While it is not necessary to ever introduce a low-mass σ meson, we describe some calculations which may be interpreted in terms of such a meson. That only represents a formal device, and no low-mass σ is to be found in experiment. However, the use of the low-mass σ as an order parameter for partial restoration of chiral symmetry at finite density is quite consistent with the picture obtained in the application of QCD sum rules to the calculation of the nucleon self-energy in nuclear matter. We discuss such sum rules to show that the linear sigma model has some limited application if we consider only spacelike values of the σ meson momentum. We also use our generalized NJL model to discuss the spectrum of scalar-isoscalar states under the assumption that the $f_0\mathrm{}\left(1370\right)\mathrm{}$ is the $1{}^3{P}_0$ $n\mathrm{n̄}$ state and the $f_0\mathrm{}\left(1710\right)\mathrm{}$ is the $1{}^3{P}_0$ $s\overline{s}$ state before consideration of quarkonium-glueball mixing. That analysis allows us to provide a microscopic model of the two $q\overline{q}$ states used by Close and Kirk in their recent description of quarkonium-glueball mixing in which they obtain wave functions of the $f_0\mathrm{}\left(1370\right),$ $f_0\mathrm{}\left(1500\right),$ and $f_0\mathrm{}\left(1710\right)\mathrm{}$ resonances. However, we also present an argument to show that the configuration assignments implied in the work of Close and Kirk are probably incorrect and that the standard scheme for the discussion of quarkonium-glueball mixing needs modification.

We examine the use of phenomenological form factors in tree level amplitudes for meson photoproduction. Two common recipes are shown to be fundamentally incorrect. An alternate form consistent with gauge invariance and crossing symmetry is proposed.