We construct an analytic model to demonstrate qualitatively the correspondence between the measured neutron total cross section and the regions where Wick’s limit is actually an equality. This model does not give sufficiently accurate quantitative results, so we extend our calculations by using the nuclear optical model with both local and global parameters. We then demonstrate how Wick’s limit can be used to give useful reaction cross-section information.

We propose a new method for treating both nuclear and Coulomb breakup processes with high accuracy and computational speed. The scattering amplitude of breakup reaction is decomposed into the lower and higher partial-wave parts. The former is calculated with the continuum-discretized coupled-channels method (CDCC) and the latter with a new version of CDCC in which the trajectory of projectile is assumed to be a straight line. Validity of this hybrid calculation is tested for ${}^{58}\mathrm{Ni}({}^8\mathrm{B},{}^7\mathrm{Be}+p){}^{58}\mathrm{Ni}$ at $240\text{MeV}$. The hybrid calculation is opening the door to the systematic analysis of ${}^8\mathrm{B}$ dissociation measured at RIKEN, MSU, and GSI, to determine the astrophysical factor $S_{17}\left(0\right)$ accurately.

We report a helicity analysis of subthreshold ${\rho }^0$ production on ${}^2\mathrm{H},$ ${}^3\mathrm{He}$, and ${}^{12}\mathrm{C}$ at low photoproduction energies. The results are indicative of a large longitudinal ${\rho }^0$ polarization $\left(l=1,m=0\right)$ and are consistent with a strong helicity-flip production mechanism. This signature is used to extract in-medium ${\rho }_L^0$ invariant mass distributions for all three nuclei in a manner which is less model dependent than previous measurements. The results are compared to kinematic and phenomenological models of the ${\rho }^0$ spectral function. The ${}^2\mathrm{H}$ and ${}^3\mathrm{He}$ data distributions support the role of $N^{*}\left(1520\right)$ excitation in shaping the in-medium ${\rho }_L^0$ invariant mass distribution, while the ${}^{12}\mathrm{C}$ distributions are consistent with quasi-free ${\rho }_L^0$ production. The data support an in-medium modification of the ${\rho }_L^0$ invariant mass distribution.

We present new measurements of the ${}^7\mathrm{Be}\left(p,\gamma \right){}^8\mathrm{B}$ cross section from ${\overline{E}}_{\text{c.m.}}=116$ to $2460\text{keV}$ (where c.m. means center-of-mass), which incorporate several improvements over our previously published experiment, also discussed here. Our new measurements lead to $S_{17}\left(0\right)=22.1\pm 0.6\left(\exp \mathrm{t}\right)\pm 0.6\left(\text{theor}\right)\text{eV}\mathrm{b}$ based on data from ${\overline{E}}_{\text{c.m.}}=116$ to $362\text{keV}$, where the central value is based on the theory of Descouvemont and Baye. The theoretical error estimate is based on the fit of 12 different theories to our low-energy data. We compare our results to other $S_{17}\left(0\right)$ values extracted from both direct $\left[{}^7\mathrm{Be}\left(p,\gamma \right){}^8\mathrm{B}\right]$ and indirect (Coulomb-dissociation and heavy-ion reaction) measurements, and show that the results of these three types of experiments are not mutually compatible. We recommend a “best” value, $S_{17}\left(0\right)=21.4\pm 0.5\left(\exp \mathrm{t}\right)\pm 0.6\left(\text{theor}\right)\text{eV}\mathrm{b}$, based on the mean of all modern direct measurements below the $1^{+}$ resonance. We also present $S$ factors at $20\text{keV}$ which is near the center of the Gamow window: the result of our measurements is $S_{17}\left(20\right)=21.4\pm 0.6\left(\exp \mathrm{t}\right)\pm 0.6\left(\text{theor}\right)\text{eV}\mathrm{b}$, and the recommended value is $S_{17}\left(20\right)=20.6\pm 0.5\left(\exp \mathrm{t}\right)\pm 0.6\left(\text{theor}\right)\text{eV}\mathrm{b}$.

In this paper we show how rotational bands of resonances can be described by using trajectories of poles of the scattering amplitude in the complex angular momentum plane: each band of resonances is represented by the evolution of a single pole lying in the first quadrant of the plane. The main result of the paper consists in showing that also the antiresonances (or echoes) can be described by trajectories of the scattering amplitude poles, instead of using the hard-sphere potential scattering as prescribed by the classical Breit-Wigner theory. The antiresonance poles lie in the fourth quadrant of the complex angular momentum plane, and are associated with nonlocal potentials which take into account the exchange forces; it derives a clear-cut separation between resonance and antiresonance poles. The evolution of these latter poles describes the passage from quantum to semiclassical physics. The theory is tested on the rotational band produced by $\alpha \text{−}\alpha$ elastic scattering and on the hadronic rotational bands in ${\pi }^{+}\text{−}p$ elastic scattering.

A new method of pseudostate discretization is proposed for the method of continuum discretized coupled channels to deal with three-body breakup processes. In the method, discrete $S$-matrix elements to the pseudo (discretized) continuum states are transformed into smooth ones to the exact continuum states of the projectile. As for the basis functions for describing pseudostate wave functions, we take real- and complex-range Gaussian functions, which form in good approximation a complete set in a finite configuration space being important for breakup processes. This “approximate-completeness” property is essential to make transformed $S$-matrix elements accurate. Moreover, the use of these Gaussian bases is expected to be very useful to describe four-body breakup processes. Accuracy of the method is tested quantitatively for two realistic examples: elastic and projectile-breakup processes in $d+{}^{58}\mathrm{Ni}$ scattering at $80\text{MeV}$ and those in ${}^6\mathrm{Li}+{}^{40}\mathrm{Ca}$ at $156\text{MeV}$.

We have measured the neutron spectra emitted in the weak decay of ${}_{\Lambda }{}^{12}\mathrm{C}$ and ${}_{\Lambda }{}^{89}\mathrm{Y}$ over the energy region above $10\text{MeV}$ in the $({\pi }^{+},K^{+})$ reaction with better statistics and an improved signal-to-background ratio. The neutron yields in the nonmesonic weak decays were obtained from the spectra. By using the proton yield of ${}_{\Lambda }{}^{12}\mathrm{C}$, the ${\Gamma }_n∕{\Gamma }_p$ ratio was estimated to be $0.51\pm 0.15\left(\text{stat}\right)$ from the neutron-to-proton yield ratio for the first time, which suggests the ${\Gamma }_n∕{\Gamma }_p$ ratio is significantly less than unity.

The problem with the use of scaling arguments for simultaneous studies of different weak interaction processes is discussed. When different neutrino scattering cross sections involving quite different momentum transfers are being compared it is difficult to define a meaningful single scaling factor to renormalize calculated cross sections. It has been suggested that the use of such scaling can be used to estimate high-energy neutrino cross sections from low-energy neutrino cross sections. This argument has lead to questions on the consistency of the magnitude of the Liquid Scintillating Neutrino Detector (LSND) muon neutrino cross sections on ${}^{12}\mathrm{C}$ relative to other lower-energy weak processes. The issue is revisited here and from inspection of the structure of the form factors involved it is seen that the problem arises from a poor description of the transition form factors at high-momentum transfer. When wave functions that reproduce the transverse magnetic inelastic $(\mathrm{e},{\mathrm{e}}^{\prime })$ scattering form factor for the $15.11\text{MeV}$ state in ${}^{12}\mathrm{C}$ are used there is no longer a need for scaling the axial current, and the different weak interactions rates involving the $T=11^{+}$ triplet in mass 12 are consistent with one another.

New values for thermal neutron capture cross sections of the tellurium isotopes ${}^{122}\mathrm{Te},{}^{124}\mathrm{Te},{}^{125}\mathrm{Te},{}^{126}\mathrm{Te},{}^{128}\mathrm{Te}$, and ${}^{130}\mathrm{Te}$ are reported. These values are based on a combination of newly determined partial $\gamma$-ray cross sections obtained from experiments on targets contained natural Te and $\gamma$ intensities per capture of individual $\text{Te}$ isotopes. Isomeric ratios for the thermal neutron capture on the even tellurium isotopes are also given.

The exclusive $\varphi$ meson production in proton-proton reactions is calculated within the resonance model. The considered model was already successfully applied to the description of $\pi$, $\eta$, $\rho$, $\omega$, $\pi \pi$ production in proton-proton collisions. The only new parameter entering into the model is the $\omega -\varphi$ mixing angle ${\theta }_{mix}$ which is taken equal to ${\theta }_{mix}\approx 3.7°$.

The isospin diffusion and other irreversible phenomena are discussed for a two-component nuclear Fermi system. The set of Boltzmann transport equations, such as that employed for reactions, is linearized, for weak deviations of a system from uniformity, in order to arrive at nonreversible fluxes linear in the nonuniformities. Besides the diffusion driven by a concentration gradient, also the diffusion driven by temperature and pressure gradients is considered. Diffusivity, conductivity, heat-conduction, and shear-viscosity coefficients are formally expressed in terms of the responses of distribution functions to the nonuniformities. The linearized Boltzmann-equation set is solved, under the approximation of constant form factors in the distribution-function responses, to find concrete expressions for the transport coefficients in terms of weighted collision integrals. The coefficients are calculated numerically for nuclear matter, using experimental nucleon-nucleon cross sections. The isospin diffusivity is inversely proportional to the neutron-proton cross section and is also sensitive to the symmetry energy. At low temperatures in symmetric matter, the diffusivity is directly proportional to the symmetry energy.

A facility for detection of scattered neutrons in the energy interval $50–130\text{MeV}$, SCANDAL, has recently been installed at the $20–180\text{MeV}$ neutron beam line of the The Svedberg Laboratory, Uppsala. Elastic neutron scattering from ${}^{12}\mathrm{C}$ and ${}^{208}\mathrm{Pb}$ has been studied at $96\text{MeV}$ in the $10°–70°$ interval. The achieved energy resolution, $3.7\text{MeV}$, is about an order of magnitude better than for any previous experiment above $65\text{MeV}$ incident energy. The present experiment represents the highest neutron energy where the ground state has been resolved from the first excited state in neutron scattering. A novel method for normalization of the absolute scale of the cross section has been used. The estimated normalization uncertainty, $3\%$, is unprecedented for a neutron-induced differential cross section measurement on a nuclear target. The results are compared with modern optical model predictions based on phenomenology or microscopic nuclear theory.

At the high densities present in the interior of neutron stars, the neutrons are condensed into the ${}^3{P}_2$ superfluid phase. While this condensation has little impact on the equation of state, it can have an important role in determining the low-temperature energy-momentum transport properties. The spontaneous breaking of baryon number by the condensate gives rise to the familiar Goldstone boson, but in addition, the spontaneous breaking of rotational invariance by the condensate gives rise to three Goldstone bosons, in general, one for each broken generator of rotations. These Goldstone bosons, which couple to $Z^0$, provide a new mechanism for neutrino emission. Using a low-energy effective field theory to describe the dynamics of these Goldstone bosons we estimate the neutrino emissivity of dense neutron matter and show that their annihilation is the dominant energy-loss mechanism over a range of temperatures.

We present the first extensive test of the critical point symmetry X(5) for the $\gamma$ degree of freedom, based in part on recent measurements for the $\gamma$ band in ${}^{152}\mathrm{Sm}$. The agreement is good for some observables including the energies and most intraband and interband transitions, but there is also a serious discrepancy for one transition.

Two $\alpha$-decay chains starting from ${}^{228}\mathrm{Pu}$ produced in the reaction of ${}^{34}\mathrm{S}+{}^{198}\mathrm{Pt}$ were observed, and the half-life was measured to be ${1.1}_{-0.5}^{+2.0}\mathrm{s}$. The half-life follows the Geiger-Nuttall curve for even-even Pu isotopes, which shows that $\alpha$ decay is the dominant decay mode. In addition, five $\alpha$-decay events of ${}^{228}\mathrm{Np}$ were observed for the first time. The evaporation residue cross sections of ${}^{228}\mathrm{Pu}$, ${}^{228}\mathrm{Np}$, and ${}^{225}\mathrm{U}$ are reproduced by a statistical model calculation.

We have studied the rapidity distribution of secondary hadrons produced in nucleus-nucleus collisions at ultrarelativistic energies within the ambit of the Landau’s hydrodynamical model. A reasonable description of the data can also be obtained by using the Bjorken’s hydrodynamical model if the boost invariance is restricted to a finite rapidity range. The sensitivity of the hadronic spectra on the equation of state vis-à-vis the velocity of sound has been discussed. The correlation between the velocity of sound and the freeze-out temperature has been indicated. The effects of the nonzero widths of various mesonic and baryonic degrees of freedom up to the mass value $\sim 2.5\text{GeV}$ are seen to be small.

The half-life of ${}^{176}\mathrm{Lu}$ has been measured using gamma-ray spectrometry, and was found to be $\left(3.677\pm 0.075\right)\times {10}^{10}\text{yr}$. The measurement geometry eliminated losses of counts due to true coincidence summing. Gamma attenuation in the sample and its container was corrected for. Agreement with previous results is discussed.

The potential energy surfaces of some superheavy nuclei are determined, using a mapping from the microscopic shell model space to a geometrical model. The content of the shell model space is determined through the knowledge of the absolute deformation and a single-particle spectrum as a function of deformation. Both have to be extracted from a microscopic model. We show that one cannot restrict to only prolate or oblate deformations because the content of the microscopic space already implies triaxiality. Also cases of $\gamma$ instability occur. The mass parameter of ${}^{254}\mathrm{No}$ is determined through the knowledge of at least one rotational state of the ground-state band. Assuming the same mass parameter for the other superheavy elements, the spectrum of each of them is determined. The following superheavy nuclei are considered: ${}^{254}\mathrm{No}$, ${}^{260}\mathrm{Rf}$, ${}^{262}\mathrm{Sg}$, ${}^{270}\mathrm{Hs}$, ${}^{274}110\left(\text{Ds}\right)$, ${}^{276}112$, and ${}^{290}114$, where ${}^{260}\mathrm{Rf}$ and ${}^{262}\mathrm{Sg}$ turn out to be $\gamma$ unstable.

We report the results from a systematic study of the quasielastic $\left(e,e^{\prime }p\right)$ reaction on ${}^{12}\mathrm{C},{}^{56}\mathrm{Fe}$, and ${}^{197}\mathrm{Au}$ performed at Jefferson Lab. We have measured nuclear transparency and extracted spectral functions (corrected for radiation) over a $Q^2$ range of $0.64–3.25{\left(\text{GeV}∕c\right)}^2$ for all three nuclei. In addition, we have extracted separated longitudinal and transverse spectral functions at $Q^2$ of 0.64 and $1.8{\left(\text{GeV}∕c\right)}^2$ for these three nuclei (except for ${}^{197}\mathrm{Au}$ at the higher $Q^2$). The spectral functions are compared to a number of theoretical calculations. The measured spectral functions differ in detail but not in overall shape from most of the theoretical models. In all three targets the measured spectral functions show considerable excess transverse strength at $Q^2=0.64{\left(\text{GeV}∕c\right)}^2$, which is much reduced at $1.8{\left(\text{GeV}∕c\right)}^2$.

Sargeant et al. conclude from model calculations in their paper [Phys. Rev. C 65 024302 (2002)] that the degree of chaos in normal deformed states does not enhance the decay out from the superdeformed band. We show that this conclusion is based on a rather unlikely assumption.