A collective model describing coherent quadrupole-octupole oscillations and rotations with a Coriolis coupling between the even-even core and the unpaired nucleon is applied to odd nuclei. The particle-core coupling provides a parity-doublet structure of the spectrum, whereas the quadrupole-octupole motion leads to a splitting of the doublet energy levels. The formalism successfully reproduces the split parity-doublet spectra and the attendant $B(E1)$ and $B(E2)$ transition probabilities in a wide range of odd-$A$ nuclei. It provides estimations for the influence of the Coriolis interaction on the collective motion and subsequently for the value of angular momentum projection $K$ on which the spectrum is built. The analysis of the energy splitting and $B(E1)$ transition probabilities between opposite parity counterparts suggests degenerate doublet structures at high angular momenta. The study provides information about the evolution of quadrupole-octupole collectivity in odd-mass nuclei.

We use the world's data on elastic electron-proton scattering and calculations of two-photon exchange effects to extract corrected values of the proton's electric and magnetic form factors over the full $Q^2$ range of the existing data. Our analysis combines the corrected Rosenbluth cross section and polarization transfer data, and is the first extraction of $G_E$ and $G_M$ including explicit two-photon exchange corrections and their associated uncertainties. In addition, we examine the angular dependence of the corrected cross sections to examine the possible nonlinearities of the cross section as a function of ɛ.

A meson-exchange model for pion-nucleon scattering was previously constructed using a three-dimensional reduction scheme of the Bethe-Salpeter equation for a model Lagrangian involving $\pi ,\eta ,N,\Delta ,\rho$, and σ fields. We thereby extend our previous work by including the $\eta N$ channel and all the $\pi N$ resonances with masses $~2$ GeV, up to the $F$ waves. The effects of the $\pi \pi N$ channels are taken into account by introducing an effective width in the resonance propagators. The extended model gives an excellent fit to both $\pi N$ phase shifts and inelasticity parameters in all channels, except $F_{17}$, up to the $F$ waves and for energies below 2 GeV. We present a new scheme for extracting the properties of overlapping resonances. The predicted values for the resonance masses and widths as well as resonance pole positions and residues are compared with the listing of the Particle Data Group.

Excited states have been populated in ${}_{52}^{110}\text{Te}$ via the ${}^{58}\mathrm{Ni}$(${}^{58}\mathrm{Ni}$,$\alpha 2p\gamma$) reaction at 250 MeV. The Gammasphere γ-ray spectrometer was augmented with ancillary detectors for charged-particle and neutron detection in order to provide clean channel selection. The known level scheme of ${}^{110}\mathrm{Te}$ has been greatly expanded with the addition of many new structures. Above spin $8^{+}$, negative-parity structures become yrast. The level scheme of ${}^{110}\mathrm{Te}$ below $30\hslash$ is discussed in this paper, including possible evidence for octupole correlations inferred from strong $B(E1)$ strengths.

High-spin states have been populated in ${}_{52}^{110}\text{Te}$ via ${}^{58}\mathrm{Ni}$(${}^{58}\mathrm{Ni}$,$\alpha 2p\gamma$) reactions at 240 and 250 MeV. The Gammasphere γ-ray spectrometer was used in conjunction with the Microball charged-particle detector. The high-spin ($I>30$) collective level scheme of ${}^{110}\mathrm{Te}$, up to $~45\hslash$, is discussed in this paper. Four new decoupled ($\Delta I=2$) high-spin structures have been observed for the first time, together with two strongly coupled ($\Delta I=1$) bands. These bands all show the characteristics of smooth band termination, and are discussed within the framework of the cranked Nilsson-Strutinsky approach.

The thermal neutron cross section and the resonance integral of the reaction ${}^{170}\mathrm{Er}$($n,\gamma$)${}^{171}\mathrm{Er}$ were measured by the Cd-ratio method using a ${}^{55}\mathrm{Mn}$ monitor as single comparator. Analytical grade ${\mathrm{MnO}}_2$ and ${\mathrm{Er}}_2{\mathrm{O}}_3$ powder samples with and without a cylindrical 1 mm Cd shield box were irradiated in an isotropic neutron field obtained from three ${}^{241}\mathrm{Am}$-Be neutron sources. The induced activities in the samples were measured with a 120.8% relative efficiency $p$-type HPGe detector. The correction factors for gamma-ray attenuation ($F_g$), thermal neutron self-shielding ($G_{\mathit{th}}$), and resonance neutron self-shielding ($G_{\mathit{epi}}$) effects, and the epithermal neutron spectrum shape factor ($\alpha$) were taken into account. The thermal neutron cross section for the ($n,\gamma$) reaction in ${}^{170}\mathrm{Er}$ has been determined to be 8.00 ± 0.56 b, relative to that of the ${}^{55}\mathrm{Mn}$ monitor. However, some previously reported experimental results compared to the present result show a large discrepancy ranging from 8.3 to 86%. The present result is, in general, in good agreement with the recently measured values by 9%. According to the definition of Cd cut-off energy at 0.55 eV, the resonance integral obtained is 44.5 ± 4.0 b, which is determined relative to the reference integral value of the ${}^{55}\mathrm{Mn}$ monitor by using cadmium ratios. The existing experimental data for the resonance integral are distributed between 18 and 43 b. The present resonance integral value agrees only with the measurement of 43 ± 5 b by Gillette [Thermal Cross Section and Resonance Integral Studies, ORNL-4155, 15 (1967)] within uncertainty limits.

Measurements of neutral pion (${\pi }^0$) production at midrapidity in $\sqrt{s_{\mathit{NN}}}=200$ GeV $\mathrm{Au}+\mathrm{Au}$ collisions as a function of transverse momentum, $p_T$, collision centrality, and angle with respect to reaction plane are presented. The data represent the final ${\pi }^0$ results from the PHENIX experiment for the first RHIC $\mathrm{Au}+\mathrm{Au}$ run at design center-of-mass energy. They include additional data obtained using the PHENIX Level-2 trigger with more than a factor of 3 increase in statistics over previously published results for $p_T>6$ GeV/$c$. We evaluate the suppression in the yield of high-$p_T$ ${\pi }^0$'s relative to pointlike scaling expectations using the nuclear modification factor $R_{\mathrm{AA}}$. We present the $p_T$ dependence of $R_{\mathrm{AA}}$ for nine bins in collision centrality. We separately integrate $R_{\mathrm{AA}}$ over larger $p_T$ bins to show more precisely the centrality dependence of the high-$p_T$ suppression. We then evaluate the dependence of the high-$p_T$ suppression on the emission angle $\Delta \varphi$ of the pions with respect to event reaction plane for seven bins in collision centrality. We show that the yields of high-$p_T$ ${\pi }^0$'s vary strongly with $\Delta \varphi$, consistent with prior measurements [1,2]. We show that this variation persists in the most peripheral bin accessible in this analysis. For the peripheral bins we observe no suppression for neutral pions produced aligned with the reaction plane, whereas the yield of ${\pi }^0$'s produced perpendicular to the reaction plane is suppressed by a factor of $~2$. We analyze the combined centrality and $\Delta \varphi$ dependence of the ${\pi }^0$ suppression in different $p_T$ bins using different possible descriptions of parton energy loss dependence on jet path-length averages to determine whether a single geometric picture can explain the observed suppression pattern.

The preliminary data of the PHENIX collaboration for the scaled variances of charged hadron multiplicity fluctuations in Au+Au at $\sqrt{s}=200$ GeV are analyzed within the model of independent sources. We use the Hadron-String-Dynamics (HSD) transport model to calculate the participant number fluctuations and the number of charged hadrons per nucleon participant in different centrality bins. This combined picture leads to a good agreement with the PHENIX data and suggests that the measured multiplicity fluctuations result dominantly from participant number fluctuations. The role of centrality selection and acceptance is discussed separately.

An analysis of the ${}^{12}\mathrm{C}$(${}^{12}\mathrm{C}$,$3\alpha$)${}^{12}\mathrm{C}$ reaction was made at beam energies between 82 and 106 MeV. Decays to both the ground state and the excited states of ${}^8\mathrm{Be}$ were isolated, allowing states of different characters to be identified. In particular, evidence was found for a previously observed state at 11.16 MeV. An analysis of the angular distributions of the unnatural parity states at 11.83 and 13.35 MeV, previously assigned $J^{\pi }=2^{-}$, calls into question the validity of these assignments, suggesting that at least one of the states may correspond to $J^{\pi }=4^{-}$. Evidence is also found for $1^{-}$ and $3^{-}$ strengths associated with broad states between 11 and 14 MeV.

The dipole response of the magic $N=50$ nucleus ${}^{88}\mathrm{Sr}$ was studied in photon-scattering experiments at the electron linear accelerator ELBE with bremsstrahlung produced at kinetic electron energies of 9.0, 13.2, and 16.0 MeV. We identified 160 levels up to an excitation energy of 12 MeV. By using polarized photons linear polarizations of about 50 γ transitions were measured that enabled parity assignments to the corresponding states. In the energy range of 6–12 MeV we identified only one $M1$ transition; all other transitions have $E1$ character. Thus, $E1$ character was proven for 63% of the total dipole strength of the observed levels in the given energy range. Statistical methods were applied to estimate intensities of inelastic transitions and to correct the intensities of the ground-state transitions for their branching ratios. In this way we derived the photoabsorption cross section up to the neutron-separation energy. This cross section matches well the photoabsorption cross section obtained from $(\gamma ,n)$ data and thus provides information about the extension of the dipole-strength distribution toward energies below the neutron-separation energy. An enhancement of $E1$ strength at 6–11 MeV may be considered as an indication for a pygmy dipole resonance.

The α and proton spectra from the ${}^{16}\mathrm{O}+{}^{40}\mathrm{Ca}$ reaction is measured at $E$(${}^{16}\mathrm{O}$) $=86$ MeV at several laboratory angles between ${54}^{°}$ and ${138}^{°}$. Analysis in terms of the statistical model for compound nuclear reactions show that an event-by-event calculation of the evaporation spectra removes discrepancy observed with standard calculations.

Searches for the permanent electric dipole moments (EDMs) of diamagnetic atoms provide powerful probes of CP-violating hadronic and semileptonic interactions. The theoretical interpretation of such experiments, however, requires careful implementation of a well-known theorem by Schiff that implies a vanishing net EDM for an atom built entirely from pointlike, nonrelativistic constituents that interact only electrostatically. Any experimental observation of a nonzero atomic EDM would result from corrections to the pointlike, nonrelativistic, electrostatic assumption. We reformulate Schiff's theorem at the operator level and delineate the electronic and nuclear operators whose atomic matrix elements generate corrections to “Schiff screening.” We obtain a form for the operator responsible for the leading correction associated with finite nuclear size—the so-called Schiff moment operator—and observe that it differs from the corresponding operator used in previous Schiff moment computations. We show that the more general Schiff moment operator reduces to the previously employed operator only under certain approximations that are not generally justified. We also identify other corrections to Schiff screening that may not be included properly in previous theoretical treatments. We discuss practical considerations for obtaining a complete computation of corrections to Schiff screening in atomic EDM calculations.

The decays of ${}^{152}\mathrm{Eu}$${}^{m,g}\to$${}^{152}\mathrm{Sm}$ have been studied by γ-ray spectroscopy using the $8\pi$ spectrometer, an array of 20 Compton-suppressed Ge detectors. Very weak γ-decay branches in ${}^{152}\mathrm{Sm}$ were investigated through γ-γ coincidence spectroscopy. All possible $E2$ transitions between states below 1550 keV with transition energies >130 keV are observed, including the previously unobserved $2_3^{+}\to 0_2^{+}$ 401 keV transition. The results, combined with existing lifetime data, provide a number of new or revised $E2$ transition strengths which are critical for clarifying the collective structure of ${}^{152}\mathrm{Sm}$ and the $N=90$ isotones.

The inclusive energy distributions of the complex fragments ($3⩽Z⩽7$) emitted from the bombardment of ${}^{12}\mathrm{C}$ by ${}^{20}\mathrm{Ne}$ beams with incident energies between 145 and 200 MeV have been measured in the angular range ${10}^{°}⩽{\theta }_{\mathrm{lab}}⩽{50}^{°}$. Damped fragment yields in all the cases have been found to have the characteristic of emission from fully energy equilibrated composites. The binary fragment yields are compared with the standard statistical model predictions. Whereas Li and Be fragments yields are in agreement with statistical-model calculations, enhanced yields of entrance channel fragments ($5⩽Z⩽7$) indicate the survival of orbiting-like process in ${}^{20}\mathrm{Ne}+{}^{12}\mathrm{C}$ system at these energies.

Longitudinal density correlations of produced matter in Au+Au collisions at $\sqrt{s_{\mathit{NN}}}=200$ GeV have been measured from the inclusive charged particle distributions as a function of pseudorapidity window sizes. The extracted $\alpha \xi$ parameter, related to the susceptibility of the density fluctuations in the long-wavelength limit, exhibits a nonmonotonic behavior as a function of the number of participant nucleons, $N_{\mathrm{part}}$. A local maximum is seen at $N_{\mathrm{part}}~90$, with corresponding energy density based on the Bjorken picture of ${\epsilon }_{\mathrm{Bj}}\tau ~2.4$ GeV/(fm${}^{2}c)$ with a transverse area size of 60 fm${}^2$. This behavior may suggest a critical phase boundary based on the Ginzburg-Landau framework.

γ-ray production cross sections for proton and α-particle interactions with ${}^{12}\mathrm{C}$, ${}^{16}\mathrm{O}$, ${}^{24}\mathrm{Mg}$, and Fe have been measured in the energy range 5–25 MeV with proton beams and 5–40 MeV with α-particle beams. Isotopically pure foils of ${}^{24}\mathrm{Mg}$ and foils of natural isotopical composition of C, MgO, and Fe have been used. γ-ray angular distributions were obtained with five high-purity Ge detectors with bismuth germanate Compton shields placed at angles of ${45}^{°}$ to ${157.5}^{°}$. Cross sections for more than 50 different γ-ray transitions were extracted, and for many of them no data have been published before. Comparison of present data with data available in the literature shows mostly good to excellent agreement. In addition to the production cross sections, high-statistics, low-background line shapes of the 4.438 MeV ${}^{12}\mathrm{C}$ γ ray from inelastic scattering off ${}^{12}\mathrm{C}$ and spallation of ${}^{16}\mathrm{O}$ were obtained. Comparison with nuclear reaction calculations shows that these data place interesting constraints on nuclear reaction models.

We present a model for inclusive electron and neutrino scattering off nuclei paying special attention to the influence of in-medium effects on the quasielastic scattering and pion-production mechanisms. Our results for electron scattering off ${}^{16}\mathrm{O}$ are compared to experimental data at beam energies ranging from 0.7 to 1.5 GeV. The good description of electron scattering serves as a benchmark for neutrino scattering.

The recent and older level shifts and widths in $\overline{p}$ atoms are analyzed. The results are fitted by an antiproton-nucleus optical potential with two basic complex strength parameters. These parameters are related to average $S$ and $P$ wave-scattering parameters in the subthreshold energy region. A fair consistency of the x-ray data for all $Z$ values, stopping $\overline{p}$ data, and the $\overline{N}N$-scattering data has been achieved. The determination of neutron density profiles at the nuclear surface is undertaken, and the determination of the neutron $R_{\mathrm{rms}}$ radii is attempted. Uncertainties due to the input data and the procedure are discussed.

The ground-state deformations of the Ge isotopes are investigated in the framework of Gogny-Hartree-Fock-Bogoliubov (HFB) and Skyrme Hartree-Fock plus pairing in the BCS approximation. Five different Skyrme parametrizations are used to explore the influence of different effective masses and spin-orbit models. There is generally good agreement for binding energies and deformations (total quadrupole moment and triaxiality) with experimental data where available (i.e., in the valley of stability). All calculations agree in predicting a strong tendency for triaxial shapes in the Ge isotopes with only a few exceptions owing to neutron (sub)shell closures. The frequent occurrence of energetically very close shape isomers indicates that the underlying deformation energy landscape is very soft. The general triaxial softness of the Ge isotopes is demonstrated in the fully triaxial potential energy surface. The differences between the forces play an increasing role with increasing neutron number. This concerns particularly the influence of the spin-orbit model, which has a visible effect on the trend of binding energies toward the drip line. Different effective mass plays an important role in predicting the quadrupole and triaxial deformations. The pairing strength only weakly affects binding energies and total quadrupole deformations, but it considerably influences triaxiality.

We have examined ${}^{158}\mathrm{Gd}$ with the ($n,n^{\text{'}}\gamma$) reaction at neutron energies up to 3.3 MeV to determine the collective character of $0^{+}$ excitations revealed in previous ${}^{160}\mathrm{Gd}$($p$, $t$) reaction studies. Moderately large $B(E2;0^{+}\to 2_1^{+})$ values are observed for transitions from some of the $0^{+}$ states lying above the pairing gap. From its excitation energy and decay properties, the $0^{+}$ excitation at 2276.7 keV is suggested as exhibiting two-phonon $\gamma \gamma$ strength. The high density of levels at similar excitation energies makes the identification of the other two-phonon states improbable.