The chiral-twin candidate bands recently observed in ${}^{136}\mathrm{Pm}$ have been extended to high spins $[I=(21\left)\mathrm{}\right]$ using the Gammasphere $\gamma$-ray spectrometer and the Microball charged-particle detector array. A more-detailed spectroscopy of the bands was possible, where the rotational alignments and $B\left(M1\mathrm{}\right)/B\left(E2\mathrm{}\right)\mathrm{}$ ratios confirm that both sequences have the $\pi h_{11/2}\nu h_{11/2}$ configuration. Particle-rotor calculations of intraband and interband transition strength ratios of the chiral-twin bands are compared with experimental values for the first time. Good agreement was found between the predicted transition strength ratios and the experimental values, thus supporting the possible chiral nature of the $\pi h_{11/2}\nu h_{11/2}$ configuration in ${}^{136}\mathrm{Pm}.$

The $\mathrm{np}$ differential cross section below 350 MeV neutron laboratory energy is studied using the energy-dependent Nijmegen partial-wave analysis PWA93. We analyze in detail three experiments, performed at LAMPF, at TRIUMF, and at the TSL facility in Uppsala. The issue of normalization of $\mathrm{np}$ cross sections is discussed, where we distinguish between measured and calculated normalizations. This analysis leads to improved treatments of the LAMPF and TRIUMF data over PWA93. It is shown that the LAMPF and TRIUMF data at $T_{\mathrm{lab}}=212\mathrm{}\hspace{0.5em}\mathrm{MeV}$ are in good agreement with PWA93 and that the LAMPF data at $T_{\mathrm{lab}}=162\mathrm{}\hspace{0.5em}\mathrm{MeV}\mathrm{}$ are also in good agreement with PWA93, but that the Uppsala data at 162 MeV are in strong disagreement with PWA93. The reason for the disagreement is, almost certainly, a systematic flaw in the slope of the Uppsala data.

The α decay of α recoil collected sources of ${}^{223}\mathrm{Fr}$ was studied using a purified ${}^{227}\mathrm{Ac}$ source. Five α groups were observed whereas previously only one was reported. Multipolarities and energies of the γ transitions between the ${}^{219}\mathrm{At}$ levels were observed for the first time which allowed spins and parities to be assigned to the levels. The systematics of the levels of ${}^{215}\mathrm{At},$ ${}^{217}\mathrm{At},$ and ${}^{219}\mathrm{At}$ show a strong similarity, but with decreasing level energies with increasing mass. The levels in ${}^{219}\mathrm{At}$ are interpreted in terms of the shell model configurations $\pi {(h}_{9/2}{)}^3\nu {(g}_{9/2}{)}^{-2}$ and $\pi {(h}_{9/2}{)}^2{f}_{7/2}\nu {(g}_{9/2}{)}^{-2}.$ Although there is no evidence of parity doublets in ${}^{215}\mathrm{At},$ ${}^{217}\mathrm{At},$ and ${}^{219}\mathrm{At},$ some of their configurations are shown to be very closely related to the quadrupole-octupole deformed ground states of ${}^{219}\mathrm{Fr},$ ${}^{221}\mathrm{Fr},$ and ${}^{223}\mathrm{Fr},$ respectively.

The signature inversion phenomenon in odd-odd nuclei is reviewed for the regions of mass numbers $A\simeq 80,$ 130, and 160. The angular momentum, frequency, and moment of inertia estimated at the signature inversion point are analyzed. The correlations found of these quantities with other nuclear parameters are discussed.

The transfer reactions of ${}^{11}\mathrm{B}{\mathrm{}(d,p)\mathrm{}}^{12}\mathrm{B}$ and ${}^{12}\mathrm{C}{\mathrm{}(d,p)\mathrm{}}^{13}\mathrm{C},$ at incident energy of $11.8\hspace{0.5em}\mathrm{MeV},$ have been used to extract asymptotic normalization coefficients and root-mean-square radii for the last neutron in ${}^{12}\mathrm{B}$ and ${}^{13}\mathrm{C}.$ It is found experimentally that the second ${(J}^{\pi }{=2\mathrm{}}^{-})$ and third ${(J}^{\pi }{=1\mathrm{}}^{-})$ excited states in ${}^{12}\mathrm{B}$ and the first ${(J}^{\pi }{=1/2\mathrm{}}^{+})$ excited state in ${}^{13}\mathrm{C}$ are the neutron halo states, whereas the third ${(J}^{\pi }{=5/2\mathrm{}}^{+})$ excited state in ${}^{13}\mathrm{C}$ is a neutron skin state.

We present measurements of the ratio of the proton elastic electromagnetic form factors, ${\mu }_p{G}_{\mathrm{Ep}}{/G}_{\mathrm{Mp}}.$ The Jefferson Lab Hall A Focal Plane Polarimeter was used to determine the longitudinal and transverse components of the recoil proton polarization in $\mathrm{ep}$ elastic scattering; the ratio of these polarization components is proportional to the ratio of the two form factors. These data reproduce the observation of Jones et al. [Phys. Rev. Lett. 84, 1398 (2000)], that the form factor ratio decreases significantly from unity above $Q^2=1\mathrm{}\hspace{0.5em}{\mathrm{GeV}}^2.$

Measurements at 18 beam kinetic energies between 1975 and 2795 MeV and at 795 MeV are reported for the $\mathrm{pp}$ elastic scattering spin correlation parameter $A_{00nn}{=(N,N;0,0\mathrm{})=C}_{\mathrm{NN}}{=A}_{\mathrm{NN}}.$ The c.m. angular range is typically 60°-100°. These results are compared to previous data from Saturne II and other accelerators. A search for energy-dependent structure at fixed c.m. angles is performed. Comparisons are made to phase shift analysis and theoretical model predictions of this spin observable.

The pion-nucleon scattering is investigated by using several three-dimensional reduction schemes of the Bethe-Salpeter equation for a model Lagrangian involving $\pi ,$ $N,$ $\Delta ,$ $\rho ,$ and $\sigma$ fields. It is found that all of the resulting meson-exchange models can give similar good descriptions of the $\pi N$ scattering data up to 400 MeV. However they have significant differences in describing the $\pi \mathrm{NN}$ and $\pi N\Delta$ form factors and the $\pi N$ off-shell t-matrix elements. We point out that these differences can be best distinguished by investigating the near threshold pion production from nucleon-nucleon collisions and pion photoproduction on the nucleon. The consequences of using these models to investigate various pion-nucleus reactions are also discussed.

A consistent systematic analysis of the synthesis of very heavy nuclei is performed within a “standard” theoretical approach without any adjustable parameters and additional simplification. Good agreement with experimental data was obtained in all the cases up to synthesis of the 102 element. It was confirmed that a process of the compound nucleus formation, starting from the instant when two heavy nuclei touch and proceeding in strong competition with the fission and quasifission processes, plays an important role in the asymmetric synthesis of superheavy elements with $Z_{\mathrm{CN}}>~104$ as well as in the symmetric fusion at $Z_{\mathrm{CN}}>~90.$ A new mechanism of the fusion-fission process for a heavy nuclear system is proposed, which takes place in the ${(A}_1,\hspace{0.5em}{A}_2)$ space, where $A_1$ and $A_2$ are two nuclei, surrounded by a certain number of common nucleons $\Delta A.\mathrm{}$ These nuclei gradually lose (or acquire) their individualities with increasing (or decreasing) the number of collectivized nucleons $\Delta A.\mathrm{}$ The driving potential in the ${(A}_1,\hspace{0.5em}{A}_2)$ space is derived, which allows the calculation of both the probability of the compound nucleus formation and the mass distribution of fission fragments in heavy ion fusion reactions.

The production of single photons in Pb+Pb collisions at relativistic energies as measured by the WA98 experiment is analyzed. A quark-gluon plasma is assumed to be formed initially, which expands, cools, hadronizes, and undergoes freeze-out. A rich hadronic equation of state is used and the transverse expansion of the interacting system is taken into account. The recent estimates of photon production in quark matter (at the two-loop level) along with the dominant reactions in the hadronic matter leading to photons are used. About 50% of the single photons are seen to have a thermal origin. An addition of the thermal and prompt photons is seen to provide a very good description of the data. Most of the thermal photons having large transverse momenta arise from the quark matter, which contributes dominantly through the mechanism of annihilation of quarks with scattering, and which in turn is possible only in a hot and dense plasma of quarks and gluons. The results are thus compatible with the formation of quark-gluon plasma and the existence of this mechanism of the production of single photons.

Double pion production in the reaction ${}^{14}\mathrm{N}+d^{16}{\mathrm{O}}^{*}+2\mathrm{}\pi$ has been investigated 99 MeV above the $2{\pi }^0$ threshold in the center-of-mass frame by recoil detection. Upper limits (2 standard deviations) to the differential cross sections for producing ${}^{16}\mathrm{O}$ in a particle-stable state and pion pairs in the invariant mass range of 270 to $310\hspace{0.5em}\mathrm{MeV}{/c}^2,$ $d\sigma /d\Omega (0\mathrm{}°{)}_{\mathrm{c}.\mathrm{m}.\mathrm{}}<1.7\mathrm{}\hspace{0.5em}\mathrm{n}\mathrm{b}/\mathrm{s}\mathrm{r}$ and $d\sigma /d\Omega (180\mathrm{}°{)}_{\mathrm{c}.\mathrm{m}.\mathrm{}}<1.3\mathrm{}\hspace{0.5em}\mathrm{n}\mathrm{b}/\mathrm{s}\mathrm{r},$ were obtained. For invariant masses above $310\hspace{0.5em}\mathrm{MeV}{/c}^2$ an upper limit to the cross section of 7 nb was obtained, assuming a constant production matrix element.

The hybrid version of tilted axis cranking has been used to study the existence of magnetic rotation in the $\Delta I=1\mathrm{}$ bands of odd-$A$ ${}^{79,81,83,85}\mathrm{Rb}$ isotopes. The bands are found to be built on prolate three quasiparticle $\pi {(g}_{9/2})\otimes \nu [g_{9/2}{\mathrm{}\left(\mathrm{fp}\right)\mathrm{}}^1]$ configuration. The results exhibit a rapid onset and decline of magnetic rotation as we go from $N=42\mathrm{}$ to 48. The ${}^{83}\mathrm{Rb}$ appears to be a better case of magnetic rotation among these four Rb isotopes.

Microscopic and macroscopic distorted wave Born approximation calculations have been performed using the molecular, standard Woods-Saxon (WS), and squared WS (Michel) $\alpha$-nucleus potentials to analyze the angular distributions of cross sections for nine transitions to the even-parity states up to excitation energy $E_x=4.26\mathrm{}\hspace{0.5em}\mathrm{MeV}$ of ${}^{31}\mathrm{P}$ and eight transitions to the even-parity states up to $E_x=3.00\mathrm{}\hspace{0.5em}\mathrm{MeV}$ of ${}^{32}\mathrm{P}$ populated in the $(\alpha ,d)$ reaction at 25 MeV incident energy on the non-$\alpha$ cluster ${}^{29,30}\mathrm{Si}$ nuclei. The parameters of the three types of the $\alpha$-nucleus potentials are determined from the elastic $\alpha$-scattering data. The molecular potential, without any adjustment to the parameters needed to fit the elastic scattering data, is able to reproduce, simultaneously, the absolute cross sections and the pattern of angular distributions, but the WS and Michel potentials, obtained from the best fits to the elastic scattering data, are found to underestimate the cross sections by one to two orders of magnitude. The spectroscopic factors for the d-cluster transfer are deduced from the full finite-range macroscopic distorted-wave Born approximation, for nine and eight transitions to states in ${}^{31}\mathrm{P}$ and ${}^{32}\mathrm{P},$ respectively, using all three potentials and are compared to those calculated by the shell model, which agree with those deduced from the fits to the data using the molecular potential only.

We calculate the scalar and transverse helicity amplitudes for the electromagnetic excitation of nucleon resonances as a function of the photon four-momentum transfer. The helicity amplitudes are decomposed into electromagnetic multipoles and connected to the $\gamma \overrightarrow{N}{N}^{*}$ transition form factors. The internal N and $N^{*}$ dynamics is described by a constituent quark model (CQM) Hamiltonian with gluon, pion, and $\sigma$-meson exchange potentials as residual interactions. The N and $N^{*}$-resonance wave functions are obtained by solving the Schrödinger equation in a harmonic oscillator basis which contains up to $N=2\mathrm{}$ excitation quanta. For the electromagnetic current we include, in addition to the one-body current, two-body exchange currents associated with the quark-quark potentials. Exchange currents provide an effective description of the cloud of $q\overline{q}$ pairs, which together with the valence quarks are important degrees of freedom in physical hadrons. We obtain sizable contributions of the two-body exchange currents for nearly all $\gamma {\mathrm{NN}}^{*}$ amplitudes. For some observables, e.g., the $C2/M1\mathrm{}$ ratio in the $\gamma \overrightarrow{N}\Delta \mathrm{}\left(1232\right)\mathrm{}$ transition, and the $M1\mathrm{}$ transition to the $N^{*}\mathrm{}\left(1440\right),$ exchange currents provide the most important contribution.

We consider a new three-nucleon force generated by the exchange of one pion in the presence of a $2N$ correlation. The underlying irreducible diagram has been recently suggested by the authors as a possible candidate to explain the puzzle of the vector analyzing powers $A_y$ and ${\mathrm{iT}}_{11}$ for nucleon-deuteron scattering. Herein, we have calculated the elastic neutron-deuteron differential cross section, $A_y,$ ${\mathrm{iT}}_{11},$ $T_{20},$ $T_{21},$ and $T_{22}$ below breakup threshold by accurately solving the Alt-Grassberger-Sandhas equations with realistic interactions. We have also studied how $A_y$ evolves below 30 MeV. The results indicate that this new 3$\mathrm{NF}$ diagram provides one possible additional contribution, with the correct spin-isospin structure, for the explanation of the origin of this puzzle.

We present here for the first time continuum-discretised-coupled-channels (CDCC) calculations for the elastic scattering and breakup of ${}^9\mathrm{Be}{+}^{12}\mathrm{C}.$ We employ a two-body cluster-folding (CF) model picture of ${}^9\mathrm{Be},$ which is considered as a ${}^5\mathrm{He}$ core plus a ${}^4\mathrm{He}$ cluster. The calculations agree well with data for elastic scattering and excitation of the ${5/2}^{-}$ resonance of ${}^9\mathrm{Be}$ at 2.43 MeV. The cross section for excitation of the ${1/2}^{+}$ resonance at 1.68 MeV is not well described by our model, the calculations being considerably smaller than the data. This is as expected from structure calculations of ${}^9\mathrm{Be},$ which suggest that this state is almost exclusively of ${}^8\mathrm{Be}+n$ cluster form.

Recent experiments have demonstrated that the rotational alignment for the $N=Z$ nuclei in the mass-80 region is considerably delayed as compared to the neighboring $N\ne Z$ nuclei. We investigate whether this observation can be understood by a known component of nuclear residual interactions. It is shown that the quadrupole-pairing interaction, which explains many of the delays known in rare-earth nuclei, does not produce the substantial delay observed for these $N=Z$ nuclei. However, the residual neutron-proton interaction, which is conjectured to be relevant for $N=Z$ nuclei, is shown to be quite important in explaining the new experimental data.

A new more precise measurement of the ground-state proton decay of ${}^{117}\mathrm{La}$ is presented $[E_p=806\mathrm{}(5)\mathrm{}\hspace{0.5em}\mathrm{keV},$ $t_{1/2,p}=26\mathrm{}\left(3\right)\mathrm{}$ ms]. ${}^{117}\mathrm{La}$ was produced via the $p4n$ fusion-evaporation channel by bombarding a ${}^{64}\mathrm{Zn}$ target with 310 and 295 MeV ${}^{58}\mathrm{Ni}$ beams. The proton decay rate is consistent with emission from a prolate deformed ${3/2}^{+}$ or ${3/2}^{-}$ Nilsson state. No evidence is found for a previously reported proton decay from a high spin isomer in ${}^{117}\mathrm{La}.$ An upper limit for the production cross section for proton decay of ${}^{116}\mathrm{La}$ at a bombarding energy of 325 MeV was established.

Recent JLab data of the differential cross section for the reaction ${p(e,e}^{\prime }p){\pi }^0$ in the invariant mass region of $1.1<W<\mathrm{}1.4\mathrm{}\hspace{0.5em}\mathrm{GeV}$ at four-momentum transfer squared $Q^2=2.8\mathrm{}$ and $4.0\hspace{0.5em}(\mathrm{GeV}{/c)}^2$ are analyzed with two models, both of which give an excellent description of most of the existing pion electroproduction data below $W<\mathrm{}1.5\mathrm{}\hspace{0.5em}\mathrm{GeV}.$ We find that at up to $Q^2=4.0\mathrm{}\hspace{0.5em}(\mathrm{GeV}{/c)}^2,$ the extracted helicity amplitudes $A_{3/2}$ and $A_{/2\mathrm{}}$ remain comparable with each other, implying that hadronic helicity is not conserved at this range of $Q^2.$ The ratios $E_{1+}{/M}_{1+}$ obtained show, starting from a small and negative value at the real photon point, a clear tendency to cross zero, and to become positive with increasing $Q^2.$ This is a possible indication of a very slow approach toward the pQCD region. Furthermore, we find that the bare helicity amplitude $A_{1/2}$ and $S_{1/2},$ but not $A_{3/2},$ starts exhibiting the scaling behavior at about $Q^2>~2.5(\mathrm{GeV}{/c)}^2.$