Independent fission yields were measured for ${}_{}{}^{82}{}_{}{}^{}\mathrm{Br}$, ${}_{}{}^{96}{}_{}{}^{}\mathrm{Nb}$, ${}_{}{}^{124}{}_{}{}^{}\mathrm{Sb}$, and ${}_{}{}^{126}{}_{}{}^{}\mathrm{Sb}$ produced by photofission of ${}_{}{}^{232}{}_{}{}^{}\mathrm{Th}$ with 27-MeV peak bremsstrahlung and for ${}_{}{}^{136}{}_{}{}^{}\mathrm{Cs}$ at 11, 15, and 27 MeV. Upper limits for the independent yields for ${}_{}{}^{86}{}_{}{}^{}\mathrm{Rb}$ and ${}_{}{}^{134}{}_{}{}^{}\mathrm{Cs}$ and mass yields for mass chains 125 and 127 were also measured for ${}_{}{}^{232}{}_{}{}^{}\mathrm{Th}$ photofission at 27 MeV. Various extensions of the ${\mathit{Z}}_{\mathit{p}}$ charge-distribution model were found to give generally good agreement with experimental measurements in the asymmetric mass regions, but less satisfactory agreement in the symmetric region. A statistical charge-distribution model incorporating post-fission dynamics correlated well with experimental values in both symmetric and asymmetric regions. The statistical-dynamic model naturally predicted pairing and shell effects which were in good agreement with experimentally observed effects. One important outcome of the statistical-dynamic model calculations was the production of a linear shape on the wings of the charge-distribution curve when proximity proton transfer after scission was incorporated into the model. Such linear shapes have previously been experimentally observed without explanation.

High spin states of ${}_{}{}^{53}{}_{}{}^{}\mathrm{Cr}$ and ${}_{}{}^{53}{}_{}{}^{}\mathrm{Mn}$ have been studied by means of the reactions ${}_{}{}^{51}{}_{}{}^{}\mathrm{V}$${(}^4$He,pnγ${)}^{53}$Cr and ${}_{}{}^{51}{}_{}{}^{}\mathrm{V}$${(}^4$He,2nγ${)}^{53}$Mn, respectively, at E=30 MeV. In-beam γ-ray singles, multiparameter coincidence, angular distribution, and Doppler-shift attenuation measurements have been performed, yielding significant new information. These include the mean lifetimes 0.${15}_{\mathrm{-}0.06}^{+0.05\mathrm{}}$ ps for the 5002.4 keV (17/$2^{\mathrm{-}}$) state in ${}_{}{}^{53}{}_{}{}^{}\mathrm{Cr}$; 0.${23}_{\mathrm{-}0.07}^{+0.08\mathrm{}}$, 0.17±0.08, and 0.${25}_{\mathrm{-}0.06}^{+0.08\mathrm{}}$ ps for the 4383.2 (17/$2^{\mathrm{-}}$), 5613.3 (19/$2^{\mathrm{-}}$), and 7961.2 (25/$2^{\mathrm{-}}$) keV states, respectively, in ${}_{}{}^{53}{}_{}{}^{}\mathrm{Mn}$; multipole mixing ratios 0.${11}_{\mathrm{-}0.11}^{+0.09\mathrm{}}$ for the 17/$2^{\mathrm{-}}$→15/$2^{\mathrm{-}}$ transition in ${}_{}{}^{53}{}_{}{}^{}\mathrm{Cr}$; -0.${16}_{\mathrm{-}0.08}^{+0.03\mathrm{}}$, -0.${05}_{\mathrm{-}0.11}^{+0.10\mathrm{}}$, and -0.${05}_{\mathrm{-}0.11}^{+0.12\mathrm{}}$ for the 19/$2^{\mathrm{-}}$→17/$2^{\mathrm{-}}$, 23/$2^{\mathrm{-}}$→21/$2^{\mathrm{-}}$, and 25/$2^{\mathrm{-}}$→23/$2^{\mathrm{-}}$ transitions, respectively, in ${}_{}{}^{53}{}_{}{}^{}\mathrm{Mn}$. The present results lend support to the existence of a K=7/2 band in ${}_{}{}^{53}{}_{}{}^{}\mathrm{Cr}$. A comparison of the experimental data with the available theoretical calculations in ${}_{}{}^{53}{}_{}{}^{}\mathrm{Mn}$ shows that yrast states with J≥17/2 are almost pure 1p4h states.

The ${}_{}{}^{14}{}_{}{}^{}\mathrm{C}$(γ,p${)}^{13}$B reaction cross section has been measured from threshold to 29.1 MeV using bremsstrahlung photons. A contribution from the ${}_{}{}^{14}{}_{}{}^{}\mathrm{C}$(γ,pn+d${)}^{12}$B reactions is included, and is significant only at the highest energies measured here. The main features of the cross section are a weak resonance at ≊22.5 MeV and a dominant, broad resonance at ≊25.6 MeV. The integrated cross section up to 29.1 MeV is 17.9±3.2 MeV mb. We deduce that essentially the entire cross section results from decay of ${\mathit{T}}_{>}$ dipole states. In combination with the reported photoneutron cross section an estimate of the total photoabsorption cross section for ${}_{}{}^{14}{}_{}{}^{}\mathrm{C}$ is obtained. The ${\mathit{T}}_{<}$ and ${\mathit{T}}_{>}$ components of the photoabsorption cross section (up to 30 MeV) are estimated to carry strengths of 92±14 MeV mb and ${31}_{\mathrm{-}5}^{+9\mathrm{}}$ MeV mb, respectively. An isospin splitting of the giant dipole resonance of 8.1±0.2 MeV is obtained. Comparisons of several shell-model calculations are made with the data, and general agreement is found. A comparison of photoabsorption cross sections for ${}_{}{}^{12,13,14}{}_{}{}^{}\mathrm{C}$ and ${}_{}{}^{16,17,18}{}_{}{}^{}\mathrm{O}$ shows dramatic redistribution of dipole strength as neutrons are added to the core nuclei.

This paper shows that, in the neutron energy region from thermal to 30 keV, the measured neutron radiative capture cross sections of ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ feeding the first four bound states in ${}_{}{}^{13}{}_{}{}^{}\mathrm{C}$ can be well understood in the framework of a channel-capture model for the E1 transition. The characteristics for each kind of transition are investigated.

The α${+}^{12}$C elastic-scattering angular distributions at ${\mathit{E}}_{\mathrm{lab}}$=120, 145, and 172.5 MeV were phase-shift analyzed and an inversion procedure for the determination of the optical potential was applied. The potential and its associated uncertainties, as a function of the radial distance, were found. Comparison is made with usual Wood-Saxon optical potential analysis.

The relativistic ‘‘no-pair’’ potential for elastic proton scattering is shown to reduce to a conventional tρ form using optimal factorization of the optical potential and the impulse approximation. The nucleon-nucleon t matrix is needed in the Breit frame and it may be obtained by boosting the NN c.m. frame t matrix. It is shown that the general form of the boost involves a Mo?ller factor, Wigner rotation operators acting on spins, and a Lorentz boost of momentum arguments. The reduction to tρ form clarifies how the no-pair analysis differs from conventional Watson or Kerman, McManus, and Thaler (KMT) analyses which usually omit Wigner rotation effects and use a Galilean boost of momentum arguments of the t matrix instead of a Lorentz boost. Recent calculations in momentum space have found rather minor off-shell effects based on the no-pair analysis but other calculations have reported substantial effects based on the KMT formalism. Off-shell effects owing to the momentum dependence of the NN t matrix are found to be considerably smaller than the difference between published no-pair and KMT calculations. It is shown that technical differences, predominantly caused by use of a Galilean boost and inaccurate Coulomb corrections, are capable of explaining the disparate results at least at 200 MeV. Wigner rotations are found to cause negligible differences in proton scattering observables at 200 and 500 MeV. KMT calculations based on a Lorentz boost and accurate Coulomb corrections in momentum space yield rather minor off-shell effects owing to the momentum dependence of the NN t matrix in essential agreement with the no-pair analysis.

The complex internucleus potential for α${\mathrm{-}}^{16}$O system is investigated with the microscopic complex effective interaction and the totally antisymmetrized many-body theory. Both real and imaginary parts of the theoretical potential, in which the differences between the oscillator-width parameters of the target and the projectile are taken into account, coincide well with the phenomenological optical potential which is uniquely determined by the experimental results. As for the incident-energy dependence of the real part of internucleus potential, it is found that 70% is caused by the effect of antisymmetrization and that the rest is explained by the energy dependence of the effective interaction. For the imaginary part both the effect of antisymmetrization and the energy dependence of the effective interaction almost equally contribute to the incident-energy dependence.

We suggest a phenomenological description of hypernuclear σ-ω Dirac mean-field theory, where the meson-baryon vertices are based on the quark model with relativistic corrections. While the model is shown to be in agreement with the σ-ω model for regular nuclei, large tensor ωYY couplings are derived for ω-hyperon vertices. This coupling, which is negligible for nucleons, is capable of resolving the problem of the small spin-orbit interaction in Λ hypernuclei within the Dirac approach, as was recently shown independently by Jennings. Our model explains the available data. It can also be the basis for more systematic theoretical studies. Predictions are thus presented for Σ and Ξ hypernuclei. Further improvements of the model are discussed.

We discuss and extend our previous predictions of dilepton depletion at small target parton momentum fraction in proton-nucleus collisions. These predictions were based on an analysis of the partonic origin of the European Muon Collaboration effect in deep-inelastic scattering (DIS) in a treatment of nuclei allowing multiquark clusters to be formed. With this input, we calculate the ratio of dimuons produced on nuclei to those produced on free nucleons. We obtain excellent agreement with data from a recent experiment, emphasizing that all input information came from our previous DIS analysis. Our calculations predict that beyond the range of presently measured data, there will be considerable dependence on the momentum carried by the annihilating parton in the incident proton.

In order to relate nuclear gamma-ray distributions to the fundamental parity-time- (PT-) and parity- (P-) violating meson-nucleon interaction, we analyze the case of the mixed (E1,M2,E3) 1189-keV gamma ray in ${}_{}{}^{182}{}_{}{}^{}\mathrm{W}$ which is populated in the decay of cryogenically oriented ${}_{}{}^{182}{}_{}{}^{}\mathrm{Ta}$. Within the framework of the quasiparticle random-phase approximation we calculate the value of the complex ‘‘irregular’’ mixing ratio ɛ(E2¯/M2) for this transition. We estimate that this mixing ratio will have a P-violating real part of ‖ɛ‖cosη≃5×${10}^{\mathrm{-}5}$ which implies an observable forward-backward asymmetry (〈J〉⋅k) in the 1189-keV gamma-ray directional distribution of ${\mathit{O}}_{\mathit{P}}$≃2×${10}^{\mathrm{-}5}$ at 10 mK. For the PT-violating imaginary part we find ‖ɛ‖sinη≃200g̃ ${}_{\mathrm{\pi }\mathit{N}\mathit{N}}{}^{(\mathit{I}=1)}{}_{}{}^{}$, where g̃ ${}_{\mathrm{\pi }\mathit{N}\mathit{N}}{}^{(\mathit{I}=1)}{}_{}{}^{}$ is the strength of the isovector PT-violating pion-nucleon coupling. An upper limit to this constant of ≲3×${10}^{\mathrm{-}10}$ may be obtained from the electric dipole moment of the neutron. Whence we conclude that at 10 mK one needs to measure the PT-violating correlation (〈J〉⋅${\mathbf{k}}_2$)(〈J〉⋅${\mathbf{k}}_1$×${\mathbf{k}}_2$) to an accuracy of ${\mathit{O}}_{\mathit{P}\mathit{T}}$≲2×${10}^{\mathrm{-}8}$ in order to improve the limit on g̃ ${}_{\mathrm{\pi }\mathit{N}\mathit{N}}{}^{(\mathit{I}=1)}{}_{}{}^{}$ set by the neutron electric dipole moment.

We point out the existence of ground-state rotational bands with identical transition energies (up to spin 8ħ) in ${}_{}{}^{240}{}_{}{}^{}\mathrm{Pu}$, ${}_{}{}^{244}{}_{}{}^{}\mathrm{Cm}$, ${}_{}{}^{246}{}_{}{}^{}\mathrm{Cm}$, and ${}_{}{}^{250}{}_{}{}^{}\mathrm{Cf}$. The corresponding transitions in the ground-state bands of ${}_{}{}^{236}{}_{}{}^{}\mathrm{U}$ and ${}_{}{}^{238}{}_{}{}^{}\mathrm{U}$ have identical energies (within ∼2 keV) up to spin 24ħ. These features are very similar to those recently observed for superdeformed bands in the mass-150 and mass-190 regions and suggest that the phenomenon of identical bands is not restricted to superdeformed bands.

The α decay of ${}_{}{}^{185}{}_{}{}^{}\mathrm{Pt}$ has been observed for the first time and α-decay branching ratios have been determined for ${}_{}{}^{185}{}_{}{}^{}\mathrm{Au}$ and ${}_{}{}^{185}{}_{}{}^{}\mathrm{Pt}$ by use of an on-line isotope separator. A single α-decay line at 4444±10 keV has been shown to result from the decay of ${}_{}{}^{185}{}_{}{}^{}\mathrm{Pt}$. The current data are insufficient to determine which of the long-lived states of ${}_{}{}^{185}{}_{}{}^{}\mathrm{Pt}$ decays via α emission. The α branching deduced from the α, γ, and x-ray data taken simultaneously is [(1.0±0.4)×${10}^{\mathrm{-}3}$]% if the α comes from the 33.0-min isomer, or [(5.0±2.0)×${10}^{\mathrm{-}3}$]% if the α comes from the 70.9-min ground state of ${}_{}{}^{185}{}_{}{}^{}\mathrm{Pt}$. In either case the transition is an unhindered one. Two lines at 5069±10 and 4826±10 keV, with relative intensities of 100 and 0.16, are attributed to the α decay of ${}_{}{}^{185}{}_{}{}^{}\mathrm{Au}$ and the deduced α branching is (0.7±0.1)%. The hindrance factors are 0.4 for the 5069-keV, and 8.8 for the 4826-keV transitions.

An experiment has been performed to search for coherent pion production due to the excitation and decay of collective Δ-hole states in the peripheral ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ ${[}^{12}$C${,}^{12}$C($1^{+}$,T=1; 15.1 MeV)] reaction at 95 MeV per nucleon. We derive an upper limit for the cross section of 60 nb. This value is consistent with present theoretical predictions.

The interaction of a nuclear gamma radiation with the atomic electron cloud gives rise to a phase shift in the nuclear electromagnetic transition amplitude. The resulting interference parameters ξ(πL) are of significance to the analysis of time-reversal experiments. We calculate these parameters for E1, E2, E3, M1, and M2 gamma transitions in a number of nuclei. We also discuss the implication of these results for simultaneous parity- and time-reversal-violating experiments.

The spin, as well as spin-averaged, twist-two structure functions of the deuteron are calculated in a version of the convolution model that incorporates relativistic and binding energy corrections. A simple parametrization of these structure functions is given in terms of a few deuteron wave-function parameters and the free nucleon structure functions. This allows for an easy comparison of structure functions calculated using different deuteron models.

I present the results of a split-bin correlation-function analysis of O+Ag(Br) and S+Ag(Br) collisions at 200 GeV/nucleon. The data are corrected for the shape of the single-particle pseudorapidity distribution, and are also corrected event by event for multiplicity. The observed pseudorapidity correlations are an order of magnitude larger than correlations from p¯p and ${\mathit{e}}^{+}$${\mathit{e}}^{\mathrm{-}}$ collisions.

Total cross sections, angular, and mass distributions for the reaction ${\mathrm{\pi }}^{\mathrm{-}}$p→${\mathrm{\pi }}^0$${\mathrm{\pi }}^0$n have been measured for ${\mathit{p}}_{\mathrm{\pi }}^{\mathrm{-}}$(lab)=7–140 MeV/c above threshold. The threshold amplitude was used to determine a value for the chiral-symmetry-breaking parameter, ξ, of -0.98±0.52. The ππ scattering lengths ${\mathit{a}}_{\mathit{I}}$ for isospin I=0 and 2 are derived from this result, together with a current-algebra sum rule. The results are ${\mathit{a}}_0$=(0.207±0.028)${\mathit{m}}_{\mathrm{\pi }}^{\mathrm{-}1}$ and ${\mathit{a}}_2$=(-0.022±0.011)${\mathit{m}}_{\mathrm{\pi }}^{\mathrm{-}1}$. These values are consistent with chiral symmetry broken by the Weinberg ππ interaction and the effects of the ${\mathit{f}}_0$(975) scalar meson.

A relativistic Faddeev calculation to describe simultaneously the reactions ${\mathit{K}}^{+}$d→${\mathit{K}}^{+}$d, ${\mathit{K}}^{+}$d→${\mathit{K}}^{+}$pn, and ${\mathit{K}}^{+}$d→${\mathit{K}}^0$pp for incident kaon momenta between 250 and 600 MeV/c has been performed. It was found that while the elastic and charge-exchange reactions are well described by the impulse approximation, that is not true in the case of the breakup reaction. However, using the distorted-wave impulse approximation suffices to describe well also this reaction. We point out the importance of the orthogonality condition between initial and final neutron proton wave functions in the breakup process. This condition needs to be taken into account when extracting ${\mathit{K}}^{+}$N phase shifts from ${\mathit{K}}^{+}$d data. We conclude therefore that the existing isospin-zero ${\mathit{K}}^{+}$N amplitudes extracted from ${\mathit{K}}^{+}$d data are not reliable.