The nucleus ${}^{14}\mathrm{O}$ has been produced via the ${}^{14}\mathrm{N}(p,n){}^{14}\mathrm{O}$ and ${}^{12}\mathrm{C}({}^3\mathrm{He},n){}^{14}\mathrm{O}$ reactions, and its half-life measured by using fast scintillators to detect the $2.3\mathrm{MeV}$ gamma ray which follows its positron decay. Possible systematic effects due to pileup or dead time in the electronics or data acquisition systems were investigated. Results from data obtained with a germanium semiconductor detector were rejected. A half-life of $70.641\left(20\right)\mathrm{s}$ was obtained.

The low- and medium-spin states of the $N=50$ neutron-rich, ${}_{37}{}^{87}\mathrm{Rb}$, ${}_{35}{}^{85}\mathrm{Br}$, ${}_{34}{}^{84}\mathrm{Se}$ and ${}_{32}{}^{82}\mathrm{Ge}$ isotones have been populated in deep-inelastic processes produced by the interaction of $460\mathrm{MeV}$ ${}^{82}\mathrm{Se}$ ions with a ${}^{192}\mathrm{Os}$ target. The subsequent $\gamma$ decay has been investigated at the Laboratori Nazionali di Legnaro using the GASP $\gamma$-ray detector array. The comparison of the experimentally observed excited states with shell-model calculations performed with and without neutron degrees of freedom has allowed the investigation of the role of the neutron-core breaking excitations and therefore of the $N=50$ shell gap. The inclusion of neutron configurations in the shell-model calculations results in an improved agreement between the experimental and calculated level energies at medium and high spin. These results highlight the considerable contribution of neutron-core particle-hole excitations across the $N=50$ shell gap to the level configurations. The overall agreement of the measured excited states with the shell-model predictions is indicative of the persistence of the $N=50$ shell gap down to $Z=32$.

Within the quark coalescence model, we study effects of resonance decays, and of the quark momentum distribution in hadrons, on the elliptic flows of stable hadrons. We find that, with the exception of rho-meson decays, the resonance decays could have a significant effect on pion elliptic flow. However, most secondary pions stem from the rho-meson decays, resulting in a reduced effect of resonance decays on their flow. Proton and kaon flows as well as the lambda flow are, however, not much affected by resonance decays. The distribution of quark momentum in hadrons also influences their elliptic flows, leading to a better agreement with experimental flow data when compared with the naive quark coalescence model, which only allows quarks with equal momentum to form a hadron.

We analyze the temperature dependence of pairing correlations in the inner crust matter of neutron stars. The study is done in a finite-temperature HFB approach and by using a zero range pairing force adjusted to the pairing properties of infinite neutron matter. Within the same approach we investigate how the specific heat of the inner crust depends on temperature, matter inhomogeneity, and the assumption used for the pairing force. It is shown that in a physical relevant range of densities the pairing properties of inner crust matter depend significantly on temperature. The finite-temperature HFB calculations show also that the specific heat is rather sensitive to the presence of nuclear clusters inside the inner crust. However, the most dramatic change of the specific heat is determined by the scenario used for the neutron matter superfluidity.

It is shown that the large density fluctuations appearing at the onset of the first order nuclear liquid-gas phase transition can play an important role in the supernovae evolution. Due to these fluctuations, the neutrino gas may be trapped inside a thin layer of matter near the protoneutron star surface. The resulting increase of pressure may induce strong particle ejection a few hundred milliseconds after the bounce of the collapse, contributing to the revival of the shock wave. The Hartree-Fock+RPA scheme, with a finite-range nucleon–nucleon effective interaction, is employed to estimate the effects of the neutrino trapping due to the strong density fluctuations, and to discuss qualitatively this self-consistent dynamical effect for supernovae evolution.

We report on a high statistics search for the ${\Xi }^{--}\left(1860\right)$ resonance in ${\Sigma }^{-}$-nucleus collisions at $340\mathrm{GeV}∕c$. No evidence for this resonance is found in our data sample which contains 676000 ${\Xi }^{-}$ candidates above background. For the decay channel ${\Xi }^{--}\left(1860\right)\to {\Xi }^{-}{\pi }^{-}$ and the kinematic range $0.15<x_F<0.9$ we find a $3\sigma$ upper limit for the production cross section of 3.1 and $3.5\mu \mathrm{b}$ per nucleon for reactions with carbon and copper, respectively.

Quark-model nucleon-nucleon and hyperon-nucleon interactions by the Kyoto-Niigata group are applied to the hypertriton calculation in a three-cluster Faddeev formalism using the two-cluster resonating-group method kernels. The most recent model, fss2, gives a reasonable result similar to the Nijmegen soft-core model NSC89, except for an appreciable contribution of higher partial waves.

We consider the effect of an exotic $S=+1$ ${\Theta }^{+}$ resonance on the scattering of neutral kaons off protons. Explicit results are presented for the $K_L^{0}p$ total cross sections.

The concept of supersymmetry and phase transitions are brought together through a study of the consistent-$Q$ Hamiltonian of the interacting Boson-Fermion model, constructed with a vibrational one-body term and a quadrupole-quadrupole interaction, and which is applicable to odd-$A$ nuclei with dominant $j=\frac{1}{2}$, $\frac{3}{2}$, and $\frac{5}{2}$ single-particle orbits. A conservation condition for the pseudo-orbital angular momentum is discussed.

A high energy-resolution ${}^{11}\mathrm{B}\left({}^3\mathrm{He},t\right){}^{11}\mathrm{C}$ experiment was performed at $0°$ and an intermediate incident energy of $140\mathrm{MeV}∕\mathrm{nucleon}$ for the study of precise Gamow-Teller (GT) transition strengths. Two doublet states at $\approx 4.5$ and $\approx 8.4\mathrm{MeV}$ were clearly resolved with a resolution of $45\mathrm{keV}$. The strengths are compared with a calculation using an ab initio no-core shell model, which became available for the $A=11$ system recently. It was found that a calculation including a three-nucleon interaction better reproduces the observed GT transition strengths.

We study nuclear and neutron matter by combining chiral effective field theory with nonperturbative lattice methods. In our approach, nucleons and pions are treated as point particles on a lattice. This allows us to probe larger volumes, lower temperatures, and greater nuclear densities than in lattice QCD. The low-energy interactions of these particles are governed by chiral effective theory, and operator coefficients are determined by fitting to zero temperature few-body scattering data. The leading dependence on the lattice spacing can be understood from the renormalization group and absorbed by renormalizing operator coefficients. In this way, we have a realistic simulation of many-body nuclear phenomena with no free parameters, a systematic expansion, and a clear theoretical connection to QCD. We present results for hot neutron matter at temperatures $20–40\mathrm{MeV}$ and densities below twice the nuclear matter density.

The three-body energy-dependent effective interaction given by the Bloch-Horowitz equation is evaluated for various shell-model oscillator spaces. The results are applied to the test cases of the three-body problem (${}^3\mathrm{H}$ and ${}^3\mathrm{He}$), where it is shown that the interaction reproduces the exact binding energy, regardless of the parametrization (number of oscillator quanta or value of the oscillator parameter $b$) of the low-energy included space. We demonstrate a nonperturbative technique for summing the excluded-space three-body ladder diagrams, but also show that accurate results can be obtained perturbatively by iterating the two-body ladders. We examine the evolution of the effective two-body and induced three-body terms as $b$ and the size of the included space $\Lambda$ are varied, including the case of a single included shell: $\Lambda \hslash \omega =0\hslash \omega$. For typical ranges of $b$, the induced effective three-body interaction, essential for giving the exact three-body binding, is found to contribute $\sim 10\%$ to the binding energy.

Translationally invariant nuclear density is derived from the shell model one-body densities by removing their spurious $0\hslash \Omega$ center-of-mass (c.m.) motion component. This paves the way to utilizing the ab initio no-core shell-model (NCSM) nuclear structure in folding approaches to optical potentials. As an illustration, the ${}^6\mathrm{He}$ diagonal and transitional densities are calculated from the NCSM wave functions obtained using the CD-Bonn nucleon-nucleon potential in the $10\hslash \Omega$ basis space. A particularly significant impact of the exact removal of the spurious c.m. motion is found for the spin-orbit part of the optical potential proportional to the derivative of the nuclear density.

We summarize the results of two experimental programs at the Alternating Gradient Synchrotron of BNL to measure the nuclear transparency of nuclei measured in the $A(p,2p)$ quasielastic scattering process near ${90}^{°}$ in the $pp$ center of mass. The incident momenta varied from 5.9 to $14.4\mathrm{GeV}∕c$, corresponding to $4.8<Q^2<12.7{(\mathrm{GeV}∕c)}^2$. Taking into account the motion of the target proton in the nucleus, the effective incident momenta extended from 5.0 to $15.8\mathrm{GeV}∕c$. First, we describe the measurements with the newer experiment, E850, which had more complete kinematic definition of quasielastic events. E850 covered a larger range of incident momenta, and thus provided more information regarding the nature of the energy dependence of the nuclear transparency. In E850 the angular dependence of the nuclear transparency near ${90}^{°}$ and the nuclear transparency deuterons were studied. Second, we review the techniques used in an earlier experiment, E834, and show that the two experiments are consistent for the carbon data. E834 also determines the nuclear transparencies for lithium, aluminum, copper, and lead nuclei as well as for carbon. A determination of the $({\pi }^{+},{\pi }^{+}p)$ transparencies is also reported. We find for both E850 and E834 that the $A(p,2p)$ nuclear transparency, unlike that for $A(e,e^{\prime }p)$ nuclear transparency, is incompatible with a constant value versus energy as predicted by Glauber calculations. The $A(p,2p)$ nuclear transparency for carbon and aluminum increases by a factor of two between 5.9 and $9.5\mathrm{GeV}∕c$ incident proton momentum. At its peak the $A(p,2p)$ nuclear transparency is $\sim 80\%$ of the constant $A(e,e^{\prime }p)$ nuclear transparency. Then the nuclear transparency falls back to a value at least as small as that at $5.9\mathrm{GeV}∕c$, and is compatible with the Glauber level again. This oscillating behavior is generally interpreted as an interplay between two components of the $pN$ scattering amplitude; one short ranged and perturbative, and the other long ranged and strongly absorbed in the nuclear medium. A study of the $A$ dependent nuclear transparency indicates that the effective cross section varies with incident momentum and is considerably smaller than the free $pN$ cross section. We suggest a number of experiments for further studies of nuclear transparency effects.

To provide information for comparison with predictions from a dynamical supersymmetry, the odd-odd nucleus ${}^{196}\mathrm{Au}$ was studied via transfer reactions. With a polarized deuteron beam we measured $(\vec{d},t)$ and $(\vec{d},\alpha )$, and with unpolarized beams we measured $(p,d)$, $({}^3\mathrm{He},d)$, and $(\alpha ,d)$ transfer reactions. From the high-resolution ${}^{197}\mathrm{Au}(p,d){}^{196}\mathrm{Au}$ spectrum, a rather complete set of excitation energies was obtained. Quantum numbers and spectroscopic factors were obtained from angular distributions of single-neutron transfer in ${}^{197}\mathrm{Au}(\vec{d},t){}^{196}\mathrm{Au}$, single-proton transfer in ${}^{195}\mathrm{Pt}({}^3\mathrm{He},d){}^{196}\mathrm{Au}$, and two-nucleon transfer ${}^{198}\mathrm{Hg}(\vec{d},\alpha ){}^{196}\mathrm{Au}$. We obtain firm $J^{\pi }$ assignments for 21 out of the 27 states with negative parity observed up to $490\mathrm{keV}$ excitation energy, by combining our data with that taken using $\gamma \gamma$ and conversion electron spectroscopy. The number of states and the firm or restricted assignments are in agreement with the predictions from the dynamical $U_{\nu }(6∕12)\otimes U_{\pi }(6∕4)$ supersymmetric scheme. Including our $(\alpha ,d)$ data, we can deduce spectroscopic factors for four different transfer channels. When model predictions of spectroscopic factors become available, these data will provide a further critical test as to what extent this symmetry is realized in nature.

Neutron emission in $E=8$, 10, 13, and $16\mathrm{MeV}∕\text{nucleon}$ ${}^{20}\mathrm{Ne}+{}^{159}\mathrm{Tb}$, ${}^{169}\mathrm{Tm}$ induced fission reactions has been further studied. The $4\pi$ configuration of the DEMON neutron multidetector allowed a detailed investigation of the pre- and postscission properties as functions of the fission parameters. The emission of the neutrons from their respective sources was found to be isotropic to a high degree. The determination of the compound-nucleus recoil velocity and the kinetic-energy release in fission suffers from smearing due to the recoil kicks imparted by the evaporated pre- and postscission light particles. Attempts to gate on these quantities lead to biases in the emission patterns of the evaporated neutrons. Specifically, with such gates, the assumption of isotropic emission is violated and attempts to analyze such gated neutron spectra with the standard fitting technique, which assumes isotropy, lead to spurious results. All these effects are clearly illustrated in this work.

Experimental data and theoretical results on charge loss $-27⩽\Delta Z⩽-1$, charge pickup $\Delta Z=+1$, and total charge-changing cross sections for $158A\mathrm{GeV}$ ${}_{82}{}^{208}\mathrm{Pb}$ ions on ${\mathrm{CH}}_2$, $\mathrm{C}$, $\mathrm{Al}$, $\mathrm{Cu}$, $\mathrm{Sn}$, and $\mathrm{Au}$ targets are presented. Calculations based on the revisited abrasion-ablation model for hadronic interaction and the relativistic electromagnetic dissociation (RELDIS) model for electromagnetic interaction describe the data. The decay of excited nuclear systems created in both types of interaction is described by the statistical multifragmentation model (SMM), which includes evaporation, fission, and multifragmentation channels. We show that at very high projectile energy the excitation energy of residual nuclei may be described on average as $\sim 40\mathrm{MeV}$ per removed nucleon, with some increase in this value compared to fragmentation of intermediate energy heavy ions at $\sim 1A\mathrm{GeV}$. The importance of the electromagnetic interaction in production of ${}_{80}\mathrm{Hg}$, ${}_{81}\mathrm{Tl}$, and ${}_{83}\mathrm{Bi}$ projectile fragments on heavy targets is shown. A strong increase of nuclear-charge pickup cross sections, forming ${}_{83}\mathrm{Bi}$, is observed in comparison to similar measurements at $10.6A\mathrm{GeV}$. This process is attributed to the electromagnetic production of a negative pion by an equivalent photon, which is quantitatively described by the RELDIS model.

Spin observables in the photoproduction of the ${\Theta }^{+}$ are explored for the purpose of determining the parity of the ${\Theta }^{+}$. Based on reflection symmetry in the scattering plane, we show that certain spin observables in the photoproduction of the ${\Theta }^{+}$ can be related directly to its parity. We also show that measurements of both the target nucleon asymmetry and the ${\Theta }^{+}$ polarization may be useful in determining the parity of ${\Theta }^{+}$ in a model-independent way. Furthermore, we show that no combination of spin observables involving only the polarization of the photon and∕or nucleon in the initial state can determine the parity of ${\Theta }^{+}$ unambiguously.

Fission-fragment mass distribution has been studied for the ${}^{16}\mathrm{O}+{}^{232}\mathrm{Th},{}^{209}\mathrm{Bi}$ systems over an energy range of $102.8–78.6\mathrm{MeV}$ and $81.6–72.6\mathrm{MeV}$, respectively, in a laboratory frame. The variance of the mass distribution $\left({\sigma }_m^2\right)$ for the ${}^{16}\mathrm{O}+{}^{209}\mathrm{Bi}$ system varies linearly with center of mass energy, while a significant anomalous behavior is found for the system ${}^{16}\mathrm{O}+{}^{232}\mathrm{Th}$. Coupled with our earlier observation for the system ${}^{19}\mathrm{F}+{}^{232}\mathrm{Th}$ [T. K. Ghosh et al., Phys. Rev. C 69, 031603(R) (2004)], we propose that the accurate measurement of mass distribution is a powerful tool to look for the onset of a nonstatistical reaction mechanism in heavy-ion-induced fission of deformed heavy nuclei.

Thermal properties of single species nucleon matter are investigated assuming a simple form of the nucleon-nucleon interaction. The nucleons are placed on a cubic lattice, hopping from site to site and interacting through a spin-dependent force, as in the extended, attractive Hubbard model. A mean field calculation in the Hartree-Fock-Bogoliubov approximation suggests that the superfluid ground state generated by strong nucleon pairing undergoes a second-order phase transition to a normal state as the temperature increases. The calculation is shown to lead to a promising description of the thermal properties of low-density neutron matter. A possibility of a density wave phase is also examined.