The properties of the Gamow-Teller (GT) $1^{+}$ states in ${}^{208}\mathrm{Bi}$ have been investigated by using the Pyatov-Salamov method. The GT resonance (GTR) energy, the contribution of the GTR $\beta$ transition strength to the Ikeda sum rule, and the differential cross sections for the ${}^{208}\mathrm{Pb}(p,n){}^{208}\mathrm{Bi}$ and ${}^{208}\mathrm{Pb}({}^3\mathrm{He},t){}^{208}\mathrm{Bi}$ charge exchange reactions at different energies have been calculated. Our results show good agreement with experimental values.

High-spin states in ${{}^{36}{}_{76}\mathrm{Kr}}_{40}$ have been populated in the ${}^{40}\mathrm{Ca}$(${}^{40}\mathrm{Ca}$,4p)${}^{76}\mathrm{Kr}$ fusion-evaporation reaction at a beam energy of 165 MeV and studied using the Gammasphere and Microball multidetector arrays. The ground-state band and two signature-split negative parity bands of ${}^{76}\mathrm{Kr}$ have been extended to $~30\hslash$. Lifetime measurements using the Doppler-shift attenuation method show that the transition quadrupole moment of these three bands decrease as they approach their maximum-spin states. Two signatures of a new rotational structure with remarkably rigid rotational behavior have been identified. The high-spin properties of these rotational bands are analyzed within the framework of configuration-dependent cranked Nilsson-Strutinsky calculations.

Nonmesonic weak decays of s-shell hypernuclei are analyzed in microscopic models for the $\Lambda N\to NN$ weak interaction. A scalar-isoscalar meson σ is introduced, and its importance in accounting for the decay rates, $n/p$ ratios, and proton asymmetry is demonstrated. Possible violation of the $\Delta I=1/2$ rule in the nonmesonic weak decay of the Λ is discussed in a phenomenological analysis, and several useful constraints are presented. The microscopic calculation shows that the current experimental data indicate a large violation of the $\Delta I=1/2$ rule, although no definite conclusion can be derived because of the large ambiguity of the decay rate of ${}_{\Lambda }^{4}H$.

We use the canonical Hartree-Fock-Bogoliubov basis to implement a self-consistent quasiparticle-random-phase approximation (QRPA) with arbitrary Skyrme energy density functionals and density-dependent pairing functionals. The point of the approach is to accurately describe multipole strength functions in spherical even-even nuclei, including weakly bound drip-line systems. We describe the method and carefully test its accuracy, particularly in handling spurious modes. To illustrate our approach, we calculate isoscalar and isovector monopole, dipole, and quadrupole strength functions in several Sn isotopes, both in the stable region and at the drip lines. We also investigate the consequences of neglecting the spin-orbit or Coulomb residual interactions in the QRPA.

Possibilities of production of new isotopes of superheavy nuclei with charge numbers 104–108 in asymmetry-exit-channel quasifission reactions are studied for the first time. The optimal conditions for the synthesis are suggested in this type of reaction. The products of suggested reactions can fill a gap of unknown isotopes between the isotopes of heaviest nuclei obtained in cold and hot complete fusion reactions.

We study neutrino-induced nucleon knockout off atomic nuclei and examine the polarization properties of the ejectile. A detailed study of the spin dependence of the outgoing nucleon is presented. The numerical results are derived within a nonrelativistic plane-wave impulse-approximation approach. Our calculations reveal large polarization asymmetries and clear dissimilarities between neutrino- and antineutrino-induced reactions. They reflect the fact that neutrino-induced nucleon knockout is dominated by the transverse axial current and gains its major contributions from forward nucleon emission and backward lepton scattering.

Low energy $n\text{−}{}^3\mathrm{H}$ elastic cross sections near the resonance peak are calculated by solving the four-nucleon problem with realistic NN interactions. Three different methods—Alt, Grassberger, and Shandas; hyperspherical harmonics; and Faddeev-Yakubovsky—have been used and their respective results are compared. We conclude on a failure of the existing NN forces to reproduce the $n\text{−}{}^3\mathrm{H}$ total cross section.

The excited levels of ${}^{122}\mathrm{Te}$ to $3.3-\text{MeV}$ excitation have been studied using $\gamma$-ray spectroscopy following inelastic neutron scattering. The decay characteristics of these levels have been determined from $\gamma$-ray excitation functions, angular distributions at $E_n-1.72,2.80$, and $3.35\text{MeV}$, Doppler shifts, and $\gamma \gamma$ coincidences. Electromagnetic transition rates were deduced for many levels, as were multipole-mixing and branching ratios. Level energies and electromagnetic transition rates were compared to interacting boson model (IBM) calculations, both with and without intruder-state mixing, and to particle-core coupling model calculations. The energies of low-lying levels of ${}^{122}\mathrm{Te}$ are well described by the IBM with intruder-state mixing calculations, and observed transition rates support emerging intruder bands built on $0^{+}$ levels. The other models considered do not produce enough low-lying positive parity states; however, U(5) energies to the four quadrupole-phonon level agree very well with observations when states with large intruder configurations are ignored. Mixed-symmetry and quadrupole-octupole excitations have been investigated, but mixing with other configurations and fragmentation of strength prohibit a clear identification of these states.

In the present paper, we carry out a detailed analysis of the presence and mixing of various families of collective bands in ${}^{188}\mathrm{Pb}$. Making use of the interacting boson model, we construct a particular intermediate basis that can be associated with the unperturbed bands used in more phenomenological studies. We use the $E2$ decay to construct a set of collective bands and discuss in detail the $(\mathrm{BE}2)$ values. Monopole transition ${\rho }^2$ values are calculated. We also perform an analysis of these theoretical results $[Q,B(E2)]$ to deduce an intrinsic quadrupole moment and the associated quadrupole deformation parameter, using an axially deformed rotor model.

Phase transitional behavior in the evolution of nuclear structure from spherical to deformed shapes is often investigated in two seemingly different contexts: within the framework of the interacting boson approximation (IBA) model, or using a geometric approach such as the X(5) or E(5) solutions. To study the connection between these two different models, two-parameter IBA-1 calculations were performed and compared to the parameter-free predictions of the X(5) model. The results show that the X(5) solution cannot be exactly reproduced by any point in the two-parameter space and that the best agreement is close to, but does not coincide with, the phase transitional region for a finite number of particles. Comparison of these two approaches with experimental data on X(5)-type nuclei shows that while X(5) and the two-parameter IBA can reproduce characteristic energy ratios in these nuclei, the IBA calculations give better agreement with the experimental electromagnetic transition strengths.

The effect of two initial exciton (particle-hole) configurations, namely 4p0h and 5p1h, on the angular distribution of neutron emission from $\alpha$-induced reactions on various thick targets have been analyzed. In the angular distribution of emitted neutrons the relative contribution of the 4p0h configuration is found to vary as the cosine of the angle of emission. Using such dependence, empirical expressions are developed for the total neutron yield, energy spectra, and angular distribution of neutrons in $\alpha$-induced reactions in the 25–200-MeV energy range. These expressions are based on empirical fits to the hybrid model calculations of neutron emission from target elements in the mass range ${}^9\mathrm{Be}$ to ${}^{209}\mathrm{Bi}$. The results of these calculations are compared with experimental data showing fairly good agreement. The empirical expressions provide a simple, fast, and reliable tool for calculating neutron emission essentially required for radiation shield design and other applications.

${}^{58}\mathrm{Ni}+{}^{58}\mathrm{Ni}$ collisions at 32 MeV/nucleon have been studied with the 4π multidetector INDRA. The evolution from binary (dissipative) collisions to a fusionlike process is evidenced with decreasing impact parameter throughout a set of experimental observables within a discriminant analysis. Preequilibrium effects and characteristics of a single-source emission are discussed. A coexistence (bimodality) between two decay mechanisms is pointed out and examined in the context of a multiple-fragment (particle) emission.

Recent relativistic heavy-ion collider (RHIC) data have shown novel nuclear modifications of moderate- tohigh-$p_T$ particle production in central $\mathrm{Au}+\mathrm{Au}$ collisions, including a suppression of hadron production and a disappearance of back-to-back hadron pairs. In this paper, we investigate whether final-state hadronic interactions of the jet fragments can reproduce the RHIC data. We find that hadronic rescattering can account for the disappearance of back-to-back hadron pairs but cannot reproduce other features of the RHIC data.

The three major electromagnetic transition quantities, $B(E2)\downarrow ,Q(J)$, and $\mu (J)$, are calculated for the yrast band of ${}^{196}\mathrm{Pt}$ by a projection formalism. The valence nucleon space is divided into four sectors of normal and abnormal parity states for neutrons and protons separately. The collective properties are evaluated in each of the four sectors and summed. A comparison is made with the IBM and SO(6) results, and it is shown that the projection calculations are performing equally well using only one fitted parameter and one normalization.

Nonstatistical fluctuation in the angular distribution of charged particles produced in high-energy nucleus-nucleus interactions is investigated by using the technique of erraticity moments. Nuclear photographic emulsion data on secondary shower track emissions collected from ${}^{16}\mathrm{O}$-Ag/Br and ${}^{32}\mathrm{S}$-Ag/Br interactions, each at an incident momentum of 200 A GeV/c, are analyzed. A generalized scaling law between the erraticity moments and the phase-space partition number is established for both sets of data. Experimental values of erraticity parameters are compared with those obtained from event samples generated by the Lund Monte Carlo model FRITIOF and by simple random numbers. In each case simulated results substantially underestimate the extent of experimentally observed nonstatistical fluctuation.

Intensity interferometry of thermal photons having transverse momenta $k_T\approx 0.1-2.0$ GeV produced in relativistic collision of heavy nuclei is studied. It is seen to provide an accurate information about the temporal and spatial structure of the interacting system. The source dimensions, and their $k_T$ dependence revealed by the photon interferometry, display a richness not seen in pion interferometry. We attribute this to the difference in the source functions, the fact that photons come out from every stage of the collision and from every point in the system, and the fact that the rate of production of photons is different for the quark-gluon plasma, which dominates the early hot stage and the hadronic matter that populates the last phase of the collision dynamics. The usefulness of this procedure is demonstrated by an application to collision of lead nuclei at the CERN SPS. Prediction for the transverse momentum dependence of the sizes for SPS, RHIC, and LHC energies are given.

Correlations in the hadron distributions produced in relativistic $\mathrm{Au}+\mathrm{Au}$ collisions are studied in the discrete wavelet expansion method. The analysis is performed in the space of pseudorapidity $(|\eta |\le 1)$ and azimuth(full $2\pi )$ in bins of transverse momentum $(p_t)$ from $0.14\le p_t\le 2.1\mathrm{GeV}/c$. In peripheral $\mathrm{Au}+\mathrm{Au}$ collisions a correlation structure ascribed to minijet fragmentation is observed. It evolves with collision centrality and $p_t$ in a way not seen before, which suggests strong dissipation of minijet fragmentation in the longitudinally expanding medium.

We studied the energy dependence of the pp elastic scattering data and the pion-photoproduction data at a ${90}^{°}\text{c.m.}$ angle in light of the new generalized counting rule derived for exclusive processes. We show that by including the helicity-nonconserving amplitudes and their interference with the Landshoff amplitude, we are able to reproduce the energy dependence of all the pp elastic cross-section and spin-correlation $(A_{NN})$ data available above the resonance region. The pion-photoproduction data can also be described by this approach; however, data with much finer energy spacing are needed to confirm the oscillations about the scaling behavior. This study strongly suggests an important role for helicity-nonconserving amplitudes related to the quark orbital angular momentum and for the interference of these amplitudes with the Landshoff amplitude at GeV energies.

We present a general derivation of the three-body spectator (Gross) equations and of the corresponding electromagnetic currents. As in a previous paper on two-body systems, the wave equations and currents are derived from those for the Bethe-Salpeter equation with the help of an algebraic method using a concise matrix notation. The three-body interactions and currents introduced by the transition to the spectator approach are isolated and the matrix elements of the e.m. current are presented in detail for a system of three indistinguishable particles, namely, for elastic scattering and for two- and three-body breakup. The general expressions are reduced to the one-boson-exchange approximation to make contact with previous work. The method is general in that it does not rely on introduction of the electromagnetic interaction with the help of the minimal replacement. It would therefore work also for other external fields.

The renormalization of the T matrix for NN scattering with a contact potential is re-examined in a nonperturbative regime through rigorous nonperturbative solutions. Based on the underlying theory, it is shown that the ultraviolet divergences in the nonperturbative solutions of the T matrix should be subtracted through “endogenous” counterterms, which in turn leads to a nontrivial prescription dependence. Moreover, employing the effective range expansion, the importance of imposing physical boundary conditions to remove the nontrivial prescription dependence, especially before making any physical claims, is discussed and highlighted. As by-products, some relations between the effective range expansion parameters are derived. We also discuss the power counting of the couplings for the nucleon-nucleon interactions and other subtle points related to the EFT framework beyond perturbative treatment.