The ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ (d,γ${)}^6$Li reaction, which proceeds through the overwhelming E2 transition, but with a small admixture of the E1 transition, is a possible mechanism for the ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$ nucleosynthesis in the Big Bang. The E1 radiation is, however, strongly suppressed in the radiative deuteron capture reaction in self-conjugate nuclei. Usually, the observed small, but not negligible, E1 radiation has been attributed to the spin-dependent electric dipole operator. In this study it is shown how the Coulomb polarization of the deuteron ${}_{}{}^4{}_{}{}^{}\mathrm{He}$(d,γ${)}^6$Li reaction. Expressly we investigate the E1 capture process which proceeds with a small change of the deuteron internal structure in the entrance channel state. The structural change of the deuteron is engendered by the Coulomb field in the system of target and deuteron and such a deviant deuteron state is surveyed by calculating the expectation value of the relative coordinate between the proton and neutron in the deuteron. We then show how the electrically polarized deuteron state releases the usual E1 selection rule, and subsequently we calculate the relative intensity of the E1 versus E2 radiation in the ${}_{}{}^4{}_{}{}^{}\mathrm{He}$(d,γ${)}^6$Li reaction.

The cross-section ratio for ${}_{}{}^3{}_{}{}^{}\mathrm{H}$(d,γ${)}^5$He relative to ${}_{}{}^3{}_{}{}^{}\mathrm{H}$(d,α)n has been measured at an effective deuteron bombarding energy of 100 keV with a NaI pair spectrometer and a tritiated-titanium target. The ratio was determined to be (1.2±0.3)×${10}^{\mathrm{-}4}$ by comparing the spectra and count rates for ${}_{}{}^3{}_{}{}^{}\mathrm{H}$(d,γ${)}^5$He and ${}_{}{}^3{}_{}{}^{}\mathrm{H}$(d,α)n with ${}_{}{}^2{}_{}{}^{}\mathrm{H}$${(}^3$He,γ${)}^5$Li and ${}_{}{}^2{}_{}{}^{}\mathrm{H}$${(}^3$He,α${)}^1$H.

Energy-dependent global Dirac optical model potentials are found by fitting proton elastic scattering data in the energy range 20–1040 MeV for ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$, ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$, ${}_{}{}^{90}{}_{}{}^{}\mathrm{Zr}$, and ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$. Three different energy- and atomic-mass-number-dependent global Dirac optical potentials are also obtained. A number of characteristic features of the potentials are discussed. In addition, the mean free path, the effective mass ${\mathit{m}}_{\mathit{e}}^{\mathrm{*}}$, the Dirac mass ${\mathit{M}}^{\mathrm{*}}$, and the relativistic energy shift ${\mathit{E}}^{\mathrm{*}}$ are calculated.

The distribution of E1 and M1 strength in ${}_{}{}^{157}{}_{}{}^{}\mathrm{Gd}$ compound nucleus has been studied. An investigation of capture of 2 and 24 keV neutrons in a ${}_{}{}^{156}{}_{}{}^{}\mathrm{Gd}$ target resulted in resonance-averaged intensities of primary gamma rays between 3.7 and 6.4 MeV. From these intensities the gamma-ray strength functions have been derived for E1 and M1 radiation. We compare several formulations of strength functions to these resonance capture and/or photoabsorption data. Further we use these prescriptions in calculations of the total average radiation width, radiative capture cross sections, and gamma-ray spectra, and compare them to available experimental information. By analyzing these results strong evidence was found for an E1 strength function which is based on a generalized Lorentzian, enhanced compared to spherical nuclei, with an energy-dependent spreading width and a nonzero limit as the energy tends to zero. For M1 radiation the giant resonance spin-flip mode is favored.

The time-dependent fields experienced by a nucleus as it passes through a crystal can cause transitions to excited nuclear states. The transition rate is especially large when the speed of the nucleus satisfies a resonance condition. Previous estimates of the nuclear excitation rates have been based on symmetry arguments and experimental data for related processes. We present here a calculation of the nuclear excitation rate which does not rely on these simplifying approximations. Using nonrelativistic quantum mechanics, the excitation cross sections of highly stripped nuclei channeled along the Si〈110〉 crystal axis have been calculated. The results are smaller than those given by previous estimates by several orders of magnitude. We note that there are similarly large discrepancies between different theoretical and experimental results for other phenomena involving coupled electronic and nuclear transitions. The reason for these disagreements is not clear.

The effects of angular momentum conservation on the properties of Ericson fluctuations in cross sections for the ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$${(}^{12}$C${,}^8$${\mathrm{Be}}_0$${)}^{16}$O(g.s.) reaction and ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$${(}^{12}$C,α${)}^{20}$${\mathrm{Ne}}^{\mathrm{*}}$ reactions leading to the 12 lowest excitations in ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$ are studied. Comparison of Hauser-Feshbach predictions to experimental measurements of the ${}_{}{}^8{}_{}{}^{}\mathrm{Be}_0^{}{}_{}{}^{}$ total cross section in the range 9≤${\mathit{E}}_{\mathrm{c}.\mathrm{m}.\mathrm{}}$≤20 MeV indicates that this reaction channel is populated primarily by a compound-nucleus mechanism. Similar results are obtained for the majority of the α-particle channels in the energy region from ${\mathit{E}}_{\mathrm{c}.\mathrm{m}.\mathrm{}}$=6.5 to 12.6 MeV. The compound-nucleus cross sections for these reactions are dominated by a narrow range of angular momenta. A statistical model that includes predicted unequal contributions from compound-nucleus levels with different spins is used to synthesize angular distributions and excitation functions for comparison to data. The results of these simulations give overall quantitatively correct estimates of the size and frequency of the fluctuations observed in the measured total cross sections and of the spins that dominate the fluctuations. Consequences for the identification of ‘‘resonances’’ are discussed.

The observed intermittent behavior in nuclear fragment distributions for ${}_{}{}^{238}{}_{}{}^{}\mathrm{U}$ at 0.96A GeV, ${}_{}{}^{84}{}_{}{}^{}\mathrm{Kr}$ at 1.52A GeV, and ${}_{}{}^{131}{}_{}{}^{}\mathrm{Xe}$ at 1.22A GeV may be due to the mixing of fragments produced under different initial conditions. Intermittent effects are significantly reduced by selecting a sample under the same initial conditions. Except the cumulants of order two, all other moments are consistent with zero within their statistical errors.

The charged secondary multiplicity distributions as a function of emitting various noninteracting projectile fragments of ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ at 4.5 GeV/c per nucleon by using nuclear emulsion detectors is presented and discussed. The correlations between various kinds of particles and the angular distributions of multiple production in ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ ion collisions are studied. Also a systematic comparison using the calculations of the cascade-evaporative model is made. An investigation of energy dependence of grey prongs produced in different interaction beams at energy range ∼(4–200)A GeV is reported.

Several recent articles assert that the increasingly precise null results of Bhabha scattering imply ‘‘model-independent’’ increasing lower bounds upon the lifetime of any neutral particle whose decay is hypothesized to yield the sharp lines of the GSI ‘‘(${\mathit{e}}^{+}$${\mathit{e}}^{\mathrm{-}}$) puzzle.’’ We discuss here reasons why such conclusions must be considered as artifacts of the assumptions made in the analysis, and not as valid scientific deductions from the data alone. Furthermore, we show that when such data are combined with additional assumptions sufficient to allow an inference about the lifetime, then the conclusion is inevitably dependent explicitly or implicitly upon the model assumed for the particle decay. In addition, we discuss why the limits asserted upon the lifetime of such a particle from the high precision agreement for ${\mathit{g}}_{\mathit{e}}$-2 between experiment and theoretical quantum electrodynamics apply only to an elementary particle, but not to a composite particle, and especially not to a leptonic composite. In the end, no valid limits upon the composite particle lifetime seems to exist at present. We also consider, in the context of the general partial width data problem, the additional experimental data which could suffice to sustain a purely empirical limit upon the lifetime, and observe that all of the present data are consistent with a composite particle with a significant amplitude in the four lepton (${\mathit{e}}^{+}$${\mathit{e}}^{+}$${\mathit{e}}^{\mathrm{-}}$${\mathit{e}}^{\mathrm{-}}$) ‘‘quadronium’’ sector. Finally, it is shown that recent preliminary Bhabha inelastic (${\mathit{e}}^{+}$${\mathit{e}}^{+}$γ) data, if confirmed, would imply the crude but genuinely empirical upper bound upon the resonance lifetime of about ${\mathrm{\tau }}_{\max }$∼2×${10}^{\mathrm{-}11}$ sec≥τ.

The differential cross section for n-p elastic scattering at 459 MeV in the c.m. angular region 50°<${\mathrm{\theta }}^{\mathrm{*}}$<180° has been measured with high statistical precision and good relative accuracy. The uncertainty in the absolute normalization (based on the simultaneously measured yield of deuterons from the np→d${\mathrm{\pi }}^0$ reaction) was initially estimated to be ∼7%. The results agree well with back-angle data obtained independently at LAMPF but less well with results from Saclay and the Princeton-Pennsylvania Accelerator and, except for a normalization difference of 10%, are fairly well represented by a phase-shift fit. The pole-extrapolation method of Chew was used to extract the pion-nucleon coupling constant ${\mathit{f}}^2$ from the back-angle portion of the data. The value obtained, ${\mathit{f}}^2$=0.069, is somewhat smaller than the values 0.0735–0.0790 obtained from analyses of pion-nucleon scattering, tending to confirm the need for an upward renormalization of the angular distribution by ∼10%.

Brayon mass splittings are analyzed in terms of a simple model with general pairwise interactions. At present, the Δ masses are poorly known from experiments. Improvement of these data would provide an opportunity to make a significant test of our understanding of electromagnetic and quark-mass contributions to hadronic masses. The problem of determining resonance masses from scattering and production data is discussed.

The problem of possible sign correlations of P-odd effects due to parity mixing on the compound nuclear stage is discussed. For an unambiguous test of the conventional model of parity violation on the compound nuclear stage, it is not enough only to measure the sign correlation of P-odd effects on some resonances, but it is necessary also to know the neutron decay amplitudes for each resonance.

The question of parity nonconservation in compound nuclear reactions is treated within the optical model. This model supplies a description of average cross section spin polarization, spin rotation, and the parity nonconservation direct testing quantity, the longitudinal asymmetry. Taking for the optical model potential a sum of a parity conserving strong complex potential and a parity nonconserving (PNC) weak potential, the above physical quantities are then evaluated, with the PNC potential treated with perturbation theory. The compound elastic, absorption, and total components of all the measurable quantities are discussed. Application is then made to the recent TRIPLE data on the n${+}^{232}$Th systems at thermal neutrons energies.

The differential cross section for the primordial reaction ${}_{}{}^8{}_{}{}^{}\mathrm{Li}$(p,n${)}^8$Be(g.s.) has been determined at ${\mathit{E}}_{\mathrm{c}.\mathrm{m}.\mathrm{}}$=1.5 MeV in the c.m. angular range 38° to 90° by use of the radioactive nuclear beam facility at the University of Notre Dame which utilizes a superconducting solenoid lens system designed at the University of Michigan, and a ${}_{}{}^8{}_{}{}^{}\mathrm{Be}$ detection technique developed at the Florida State University. A ${}_{}{}^8{}_{}{}^{}\mathrm{Li}$ beam of approximately ${10}^7$ pps is used to infer a total cross section of 21±2 mb, with a 20% absolute cross section uncertainty. This total cross section is a factor of two smaller than a conventional Hauser-Feshbach calculation and it is also much smaller than that of some other ${}_{}{}^8{}_{}{}^{}\mathrm{Li}$ burning reactions.

Lifetimes of the first excited states of the N=82 isotones ${}_{}{}^{138}{}_{}{}^{}\mathrm{Ba}$, ${}_{}{}^{140}{}_{}{}^{}\mathrm{Ce}$, and ${}_{}{}^{142}{}_{}{}^{}\mathrm{Nd}$ have been measured simultaneously with the Doppler-shift attenuation method following inelastic neutron scattering and are found to be in excellent agreement with adopted literature values. In addition, lifetimes of excited states in heavier isotopes of neodymium have been determined. Of special interest are the E1 transitions for which transition strengths greater than ${10}^{\mathrm{-}3}$ W.u. are observed.

The vector analyzing power ${\mathit{iT}}_{11}$ of the reaction πd→pp was measured at ${\mathit{T}}_{\mathrm{\pi }}$=350, 400, and 450 MeV. The results obtained at ${\mathit{T}}_{\mathrm{\pi }}$=350 MeV are in agreement with earlier measurements of ${\mathit{iT}}_{11}$ at 325 MeV. With increasing energies our results show a marked increase in the vector analyzing power up to a value close to its theoretical limit at ${\mathit{T}}_{\mathrm{\pi }}$=450 MeV (√s =2.40 GeV). In this energy region broad structure has been found in earlier measurements of dσ/dΩ and ${\mathit{A}}_{\mathit{y}0}$.

A method for truncating the nuclear shell model in terms of Nilsson orbits is developed and tested in the context of a simple model that admits coexistence between deformed and spherical configurations. The method reproduces the exact-diagonalization spectra of both the spherical and deformed configurations if angular momentum projection is carried out prior to diagonalization. Implementation of this method in m-scheme shell-model codes is discussed.

Earlier calculations of fission fragment anisotropies made with the use of the standard saddle point statistical model have been corrected to include the effects of prefission neutron emission. These calculations are compared with the data reported earlier for the fissioning systems formed by projectile-target combinations of ${}_{}{}^{10}{}_{}{}^{}\mathrm{B}$, ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$, ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$, and ${}_{}{}^{19}{}_{}{}^{}\mathrm{F}$ on ${}_{}{}^{232}{}_{}{}^{}\mathrm{Th}$ and ${}_{}{}^{237}{}_{}{}^{}\mathrm{Np}$ and ${}_{}{}^9{}_{}{}^{}\mathrm{Be}$ on ${}_{}{}^{232}{}_{}{}^{}\mathrm{Th}$. It is seen that for these systems the conclusions reached earlier regarding the entrance channel dependence of the fission fragment anisotropy as a function of mass (charge) asymmetry are not affected by the inclusion of corrections due to prefission neutron emission.

The very large electromagnetic dissociation (EMD) cross section recently observed by Hill, Wohn, Schwellenbach, and Smith do not agree with Weizsacker-Williams (WW) theory or any simple modification thereof. Calculations are presented for the reaction probabilities for this experiment and the entire single and double nucleon removal EMD data set. It is found that for those few reactions where theory and experiment disagree, the probabilities are exceptionally large. This indicates that WW theory is not valid for these reactions and that one must consider higher order corrections and perhaps even a nonperturbative approach to quantum electrodynamics.

We present the analysis of multiplicity distributions of charged secondary particles produced in minimum bias and central interactions of ${}_{}{}^{32}{}_{}{}^{}\mathrm{S}$ and ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ at 200A GeV, ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ at 60A GeV, ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$ at 14.5A GeV, and protons at 800 GeV with nuclear emulsion in terms of the information entropy and higher generalized fractal dimensions. Comparisons of the ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$ data with Monte Carlo model venus and ${}_{}{}^{32}{}_{}{}^{}\mathrm{S}$ data with fritiof model are also presented.