We measured excitation functions for several products of the complete fusion of ${}_{}{}^{22}{}_{}{}^{}\mathrm{Ne}$ and ${}_{}{}^{133}{}_{}{}^{}\mathrm{Cs}$. The compound nucleus, ${}_{}{}^{155}{}_{}{}^{}\mathrm{Tb}$, was produced with six excitation energies between 50 and 100 MeV. The experimental data can be well reproduced with an evaporation code which addresses the problem of particle emission at high angular momentum. The production of high-spin isomeric species is favored over the production of low-spin species. We introduce a new computer code which reproduces the trend of the isomer ratios with reaction energy. However, a lack of detailed knowledge of the nuclear levels near the high-spin isomers prevents any great accuracy.

The cross sections for ${}_{}{}^{250}{}_{}{}^{}\mathrm{Fm}$, ${}_{}{}^{244\mathrm{-}246}{}_{}{}^{}\mathrm{Cf}$, ${}_{}{}^{242\mathrm{-}244}{}_{}{}^{}\mathrm{Cm}$, and ${}_{}{}^{242}{}_{}{}^{}\mathrm{Am}_{}^{\mathrm{g}}{}_{}{}^{}$ produced by the ${}_{}{}^{12}{}_{}{}^{}$C${+\mathrm{}}^{242}$Pu and the ${}_{}{}^{16}{}_{}{}^{}$O${+\mathrm{}}^{238}$U reactions leading to the same compound nucleus of ${}_{}{}^{254}{}_{}{}^{}\mathrm{Fm}$ have been measured by using radiochemical methods. The excitation functions show that the difference between the ${}_{}{}^{12}{}_{}{}^{}$C${+\mathrm{}}^{242}$Pu and the ${}_{}{}^{16}{}_{}{}^{}$O${+\mathrm{}}^{238}$U reactions can be attributed mainly to the Coulomb barriers. Our results were compared with others reported previously for ${}_{}{}^{22}{}_{}{}^{}$Ne${+\mathrm{}}^{232}$Th, ${}_{}{}^{12}{}_{}{}^{}$C${+\mathrm{}}^{238}$U, ${}_{}{}^{12}{}_{}{}^{}$C${+\mathrm{}}^{240}$,241Pu, ${}_{}{}^{13}{}_{}{}^{}$C${+\mathrm{}}^{241}$Pu, ${}_{}{}^{16}{}_{}{}^{}$O${+\mathrm{}}^{233}$U, and ${}_{}{}^{16}{}_{}{}^{}$O${+\mathrm{}}^{242}$Pu reaction systems, and support a mechanism involving transfer of α-particle clusters (C,Be,He) from projectile to target for the production of Cf and Cm isotopes.

Rayleigh’s stability criterion for a cylinder of a classical, incompressible fluid against pinching is generalized to a fluid with a diffuse surface, appropriate in particular for applications in nuclear physics. The stability is governed by the wavelength of the perturbation and the surface thickness, both in comparison to the cylinder radius. The stability diagram is constructed.

The yield of particle-bound excited states of ejectiles produced in the reaction 9.5 MeV/nucleon ${}_{}{}^{19}{}_{}{}^{}$F${+}^{159}$Tb has been determined by use of particle γ-ray coincidence techniques. The bound excited state population fraction for most projectile-like fragments shows no dependence on particle kinetic energy. In these cases the fractions are inconsistent with a Boltzmann population distribution, but they support the hypothesis of a substantial sequential decay component with a strong preference for the ground state of the residual fragment. For a few detected ejectiles there is a strong dependence of the excited state fraction on particle kinetic energy. This dependence is in agreement with that expected for a binary process in which the projectile-like fragment gets a small but constant fraction of the total available excitation energy.

If the local color symmetry in a quark-gluon matter is broken, the expectation value of the gluon field 〈$A_{\mu }^a$(x)〉 may be different from zero. Such a gluon-condensed phase has been found in mean field approximation. The gluon-condensed phase is characterized by a static, periodic chromomagnetic field, which is coupled to a periodic spin-color density distribution of quarks and antiquarks. Transitions of first and second order type have been found between the gluon-condensed and normal phases, the latter characterized by the vanishing value of the mean gluon field.

The absolute electrofission cross section of ${}_{}{}^{209}{}_{}{}^{}\mathrm{Bi}$ was measured in the energy range 43–250 MeV; the photofission cross section was deduced by means of the virtual-photon technique in the same energy range. The analysis of the fission probability, which was estimated from the photofission cross section and photoabsorption cross sections available in the literature, showed that ${}_{}{}^{209}{}_{}{}^{}\mathrm{Bi}$ undergoes fission through compound nucleus formation for energies between the threshold and the Δ region. It was found that Levinger’s modified quasi-deuteron model cross section accounts for all the compound nucleus cross section, even at energies well above the pion threshold. The ineffectiveness of the pion photoproduction excitation mechanism in inducing fission of ${}_{}{}^{209}{}_{}{}^{}\mathrm{Bi}$ could be explained in terms of the role played by the pion mean free path inside the nucleus.

We compare two ‘‘conventional’’ relativistic unitary isobar models for the NN→NNπ reaction. One model, which preserves two- and three-body unitarity, contains only pion exchange, while the other, based on a two-body coupled-channels approach, includes heavier meson exchanges. Thus, we attempt to identify the model dependence of predictions for the NN→NNπ process over a large part of final state phase space. Differential cross sections and a variety of spin observables are examined. Implications for the identification of exotic dibaryon resonances are briefly discussed.

Yields of the ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$(${\mathrm{K}}^{\mathrm{-}}$, ${\pi }^{\mathrm{-}}$${)}_{{\mathrm{}}^1{\mathrm{}}_{\mathrm{\Lambda }}^2}$C and ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$(${\mathrm{K}}^{\mathrm{-}}$,${\pi }^{+}$)${}_{}^1$ ${}_{\Sigma }{}^2{}_{}{}^{}$Be stopped-kaon reactions to 1s and 1p hypernuclear states are studied in detail within the distorted wave impulse approximation, employing realistic ${\mathrm{K}}^{\mathrm{-}}$ atomic wave functions and pion distorted waves. The calculated Λ-hypernuclear yields are weaker than the Σ-hypernuclear yields by more than an order of magnitude, particularly because the outgoing pion wave is strongly damped in the Λ production region due to the proximity to the 3,3 resonance, and are sensitive to within factors of 1.5–3 to the choice of pion optical potential. The largest uncertainty, by as much as a factor of 3.5, is that for the ratio of $2^{+}$ to $0^{+}$ excitations. The calculated Σ-hypernuclear yields, on the other hand, are generally stable, to within 20%, to variations in the input parameters. The results of the calculation are compared with old and new data of stopped-kaon reactions on ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$, and with previous theoretical reports. Yields are also calculated for production of 1$p_{\Lambda }$ states in ${}_{{\mathrm{}}^1{\mathrm{}}_{\mathrm{\Lambda }}^6}{}^{}{}_{}{}^{}\mathrm{O}$ which decay only by proton emission.

The spin-isospin volume responses of a finite nucleus are evaluated in the random phase approximation framework, utilizing a harmonic oscillator basis. Particular emphasis is given to the mixing between the longitudinal (σ⋅q) and transverse (σ×q) couplings, which arise at the nuclear surface. We show that it reduces somewhat the contrast between the two spin responses. We compare the calculated transverse response with the experimental one extracted from deep inelastic electron scattering.

Most applications of the cloudy bag model to πN scattering involve unitarizing the bare diagrams arising from the Lagrangian by iterating in a Lippmann-Schwinger equation. However, analyses of the renormalization of the coupling constant proceed by iterating the Lagrangian to a given order in the bare coupling constant. These two different approaches means there is an inconsistency between the calculation of phase shifts and the calculation of renormalization. A remedy to this problem is presented that has the added advantage of improving the fit to the phase shifts in the $P_{11}$ channel. This is achieved by using physical values of the coupling constant in the crossed diagram which reduces the repulsion rather than adds attraction. This approach can be justified by examining equations for the ππN system that incorporate three-body unitarity.

Differential cross sections and analyzing powers were measured for the ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$(p→,t${)}^{16}$O reaction at 90 MeV. The angular distributions for six triton groups are compared with calculations performed in the zero-range and finite-range distorted wave Born approximation. The present results were augmented by data available in the literature in order to study the excitation function σ($T_p$) for the $J^{\pi }$${=2\mathrm{}}^{+}$ state at $E_x$=9.85 MeV over the range of $T_p$=20 to 90 MeV in comparison with distorted wave Born approximation calculations.

The energy dependence of the part of inclusive spectra corresponding to statistical breakup has been explained modifying the Fermi model for pion production. The modification consists of introducing an energy variable volume of interaction that is dependent on the de Broglie wavelength of the incident channel. The comparison with experiments is satisfactory.

The analyzing powers of 14 and 17 MeV neutrons elastically scattered from ${}_{}{}^{27}{}_{}{}^{}\mathrm{Al}$ have been measured. Two spherical optical model analyses of these and previously published data have been performed. The first one, which concentrated only on neutron cross section data at 14 and 17 MeV and the new analyzing powers, led to a new set of spherical optical model parameters, including a spin-orbit strength and a diffuseness of about 5.6 MeV and 0.36 fm, respectively. The second incorporated cross section and analyzing power data for proton scattering at slightly higher energies, to compensate for Coulomb energy differences. The data were successfully described with a set of parameters which included isospin-dependent potentials with isospin parameters $V_{1R}$=22.4 MeV and $W_{1D}$=15.7 MeV.

The ${}_{}{}^2{}_{}{}^{}$H(n,γ${)}^3$H reaction has been studied with polarized and unpolarized neutrons of energies ranging from 9 to 14 MeV. Angular distributions of cross section were measured at $E_{\mathrm{n}}$(lab)=9.0, 10.8, and 14.0 MeV, σ(90°) was measured at 6.85 MeV, and an analyzing-power angular distribution was measured at 9.0 MeV. The results for σ(theta) agree with the existing ${}_{}{}^3{}_{}{}^{}\mathrm{H}$(γ,n${)}^2$H data after detailed balancing. The resulting ${}_{}{}^3{}_{}{}^{}\mathrm{He}$(γ,p)${/}^3$H(γ,n) ratio for 90° cross sections is 1.1±0.15 down to $E_x$=10.8 MeV. The T-matrix analysis of the data indicates ∼3% for the E2 contribution to the capture cross section—comparable to that found earlier for ${}_{}{}^2{}_{}{}^{}\mathrm{H}$(p,γ${)}^3$He and in contrast to the predictions [${\sigma }_{\mathrm{n}\left(\mathrm{E}2\right)/{\sigma }_{\mathrm{p}\left(\mathrm{E}2\right)}}$=1/25] of a two-body direct-capture calculation.

The first T=2 state in ${}_{}{}^8{}_{}{}^{}\mathrm{Be}$ ($E_x$=27.483 MeV) has been studied by means of the isospin-forbidden resonance in the reaction d${+\mathrm{}}^6$Li→α+α. Angular distributions of the cross section and of the four analyzing powers for the reaction ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$(d→,α${)\mathrm{}}^4$He have been measured at energies above, below, and on resonance. Off-resonance analyzing power measurements have also been obtained for ${}_{}{}^2{}_{}{}^{}\mathrm{H}$${(}^6$Li→,α${)\mathrm{}}^4$He. Because of the symmetry properties of the reaction, the number of independent collision matrix elements is fairly small, and this makes it possible to determine the matrix elements directly by fitting the data. By comparing the matrix elements, one can determine partial widths (${\Gamma }_0$ and ${\Gamma }_2$) for decay of the ${}_{}{}^8{}_{}{}^{}\mathrm{Be}$ state into d${+\mathrm{}}^6$Li states with channel spin 0 and 2. The measured ratio of the partial widths is ${\Gamma }_2$/${\Gamma }_0$=0.322±0.091.

We present an analysis of the E2 strength data recently available from thermal radiative neutron capture within the context of direct capture theory. The radiative capture data require a neutron E2 effective charge identical to the one used in bound state shell model calculations, in marked contrast to the E1 situation. We suggest that this difference has its origin in the nature of the coupling governing the particle-core interaction in E2 and E1 radiative capture processes.

Differential cross sections for the ${}_{}{}^2{}_{}{}^{}\mathrm{H}$(γ,p)n reaction were measured at five laboratory angles from 32.5° to 130°, for photon energies between 100 and 255 MeV, in 10 MeV steps. A quasi-monochromatic photon beam, obtained by positron in-flight annihilation on a liquid hydrogen radiator, was used, and the photon spectrum was measured on-line by a pair spectrometer. The normalization uncertainty is within ±5%. Data agree, within the total errors, with recent results of a tagged-photon experiment and of a measurement of the inverse process. The measured angular distributions were fitted by a sum of Legendre polynomials, and the results compared with recent calculations. Significant departures from the calculated angular distribution asymmetry have been found.

Analyzing-power measurements were performed for the ${}_{}{}^{48}{}_{}{}^{}\mathrm{Ca}$(p,n${)}^{48}$Sc reaction at 134 MeV in about 6° steps from 0° to 60°. The overall neutron energy resolution varied from about 400 keV for angles out to 42° to about 700 keV at wider angles. Analyzing-power angular distributions were extracted for the (π$f_{7/2}$,ν$f_{7/2}^{\mathrm{-}1}$) octet of states, the $1^{+}$ Gamow-Teller giant resonance, and the T=4, $1^{+}$ state at $E_x$=16.8 MeV. All of these angular distributions are described reasonably well by ‘‘standard’’ distorted-wave impulse approximation calculations. A qualitative difference is observed in the analyzing power between the transitions to the low-lying $0^{+}$ and $1^{+}$ states compared to the transition to the high-lying $1^{+}$ state. This difference appears to be associated with a sensitivity to the predominant particle-hole structure of the final states, viz., (π$f_{7/2}$,ν$f_{7/2}^{\mathrm{-}1}$) versus (π$f_{5/2}$,ν$f_{7/2}^{\mathrm{-}1}$). This sensitivity is ascribed to the difference in nonlocality contributions to the two different 1p1h excitations. Excitation-energy plots of the analyzing power were extracted at each angle. No characteristic signature of spin-transfer strength is observed in the region of the Gamow-Teller giant resonance.

Measurement of the total and differential elastic cross sections for the ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$+n reaction are reported for the neutron energy range E=50–1005 keV. The data have been analyzed in terms of partial waves using the R-matrix formalism. The results were used to deduce optical model potentials near threshold. When the real part is expressed solely in terms of an ‘‘effective’’ volume and surface spin-orbit components, it is found that the depth of the ‘‘effective’’ volume potential exhibits an lJ dependence. It is noted that because of differences in the continuum wave functions in the surface region, such an effect could arise if the actual potential contained a real surface term. Relevance to the ‘‘Fermi surface anomaly’’ is mentioned. The observed reduced neutron strengths are compared with predictions from three microscopic models and good agreement is found.

The energy-level structure of ${}_{}{}^{99}{}_{}{}^{}\mathrm{Ru}$ was studied using the ${}_{}{}^{98}{}_{}{}^{}\mathrm{Mo}$${(}^3$He, 2nγ${)}^{99}$Ru reaction at a bombarding energy of 13 MeV, in an attempt to populate an extensive set of non-yrast states. The experiments included γ-ray excitation functions, γ-γ coincidence measurements, γ-ray angular distributions, and γ-ray linear polarization measurements. A large number of non-yrast states were observed, with angular momenta ranging from (1/2) to (17/2). The comparison of experimental energies and electromagnetic transition properties to the predictions of a particle-rotor model is presented. This interpretation suggests that several complete particle-core multiplets have been populated. The population of non-yrast states is attributable to the properties of the reaction rather than any details of the nuclear structure involved.