Starting from a non-Markovian conserving relaxation time approximation for collisions we derive coupled dispersion relations for asymmetric nuclear matter. The isovector and isoscalar modes are coupled due to asymmetric nuclear meanfield acting on neutrons and protons differently. A further coupling is observed by collisional correlations. The latter one leads to the appearance of a new soft mode besides isoscalar and isovector modes in the system. We suggest that this mode might be observable in asymmetric systems. This soft mode approaches the isovector mode for high temperatures. At the same time the isovector mode remains finite and approaches a constant value at higher temperatures showing a transition from zero sound like damping to first sound. The damping of the new soft mode is first sound like at all temperatures.

The breakup of ${}^8\mathrm{B}$ on ${}^{58}\mathrm{Ni}$ below the Coulomb barrier was measured recently with the aim of determining the Coulomb breakup components. We reexamine this reaction, and perform one-step quantum-mechanical calculations that include $E1,$ $E2,$ and nuclear contributions. We show that the nuclear contribution is by no means negligible at the intermediate angular range where data were taken. Our results indicate that, for an accurate description of this reaction, Coulomb $E1,$ $E2,$ and nuclear processes all have to be taken into account.

Using a confining, Dyson-Schwinger equation model of QCD at finite temperature $\mathrm{}\left(T\right)\mathrm{}$ and chemical potential (μ), we study the behavior of $〈\overline{q}q〉,$ $m_{\pi },$ $f_{\pi }$ and the masses of the ρ- and φ-mesons. For each of these quantities there is a necessary anticorrelation between its response to $T$ and its response to μ. $\left(-〈\overline{q}q〉\right)$ and $f_{\pi }$ decrease with $T$ and increase with μ; $m_{\pi }$ is almost insensitive to $T$ and μ until very near the border of the confinement domain; the mass of the longitudinal component of the vector mesons increases with $T$ and decreases with μ. At $T=0,$ the ρ-meson mass is reduced by approximately 15% at nuclear matter density. These results are a consequence of the necessary momentum-dependence of the dressed-quark self-energy.

A global systematic analysis relating the asymptotic enhancement of sub-barrier fusion cross sections with the product of the coupling strength times the value of the Coulomb barrier is presented. It is found that all systems involving static deformations, inelastic excitations, and transfer degrees of freedom, follow the same systematic trend. In the analysis, the Coulomb barrier plays a central role in amplifying the relevance of the couplings associated with a particular degree of freedom.

The transverse polarization transfer coefficient $K_y^{y^{\prime }}$ has been measured for the ${}^2\mathrm{H}(\overrightarrow{d},\overrightarrow{n}{)}^3\mathrm{He}$ reaction at 0° for deuteron energies around 13 MeV, using a purely vector-polarized deuteron beam. At $0.666\pm 0.013,$ $K_y^{y^{\prime }}\left(0\mathrm{}°\right)$ was found to be significantly larger than the values used frequently in the past to deduce the neutron polarization from the polarization of the deuteron beam.

Dispersive effects have been investigated by comparing elastic scattering of electrons and positrons from ${}^{12}\mathrm{C}$ at the Saclay Linear Accelerator. The results demonstrate that dispersive effects at energies of 262 MeV and 450 MeV are less than 2% below the first diffraction minimum $[0.95<\mathrm{}{q}_{\mathrm{eff}}\hspace{0.5em}({\mathrm{fm}}^{-1})<\mathrm{}1.66\mathrm{}$] in agreement with the prediction of Friar and Rosen. At the position of this minimum ${(q}_{\mathrm{eff}}=1.84\mathrm{}\hspace{0.5em}{\mathrm{fm}}^{-1})$, the deviation between the positron scattering cross section and the cross section derived from the electron results is $-44\%\pm 30\%$.

We have measured the $\mathrm{pd}$ elastic scattering with an electron-cooled beam of a proton storage ring and an internal jet target operated with HD gas. The accurately known H/D ratio is used to transfer the precision of existing $\mathrm{pp}$ scattering data to the $\mathrm{pd}$ cross sections. Measurements were performed for proton energies between 200 and 300 MeV in the angular range $11°<~{\Theta }_{\mathrm{c}.\mathrm{m}.\mathrm{}}<~\hspace{0.5em}29°.$ The results are compared to nonrelativistic Faddeev calculations with different nucleon-nucleon interactions and total angular momenta $j<~5$ in the $\mathrm{NN}$ subsystem. The impact of a genuine $3N$ force is investigated. The discrepancies between data and calculations increase with projectile energy.

The ${}^2\mathrm{H}(\gamma ,pp{\pi }^{-})$ reaction cross section has been measured in the energy range 220 $\mathrm{MeV}<~E_{\gamma }<~280$ MeV at the Saskatchewan Accelerator Laboratory using the Saskatchewan-Alberta Large Acceptance Detector. This is the first reported measurement of the ${\gamma }^2\overrightarrow{H}\mathrm{pp}{\pi }^{-}$ cross section covering a wide range of phase space in an attempt to study final state interactions. The cross section for this reaction is compared to the calculation of Blomqvist and Laget with various contributions from final state interactions. Blomqvist and Laget’s theory is successful in describing the shapes of the distributions, as well as the overall magnitude of the cross section. The different final state interactions have an overall effect of 10%–15% on the single differential cross section, with the calculation that includes the $\Delta -N$ interaction having the best agreement with the data.

A nonzero difference of the analyzing powers due to charge symmetry breaking has been measured with high precision in $\mathrm{np}$ elastic scattering at a neutron beam energy of 347 MeV. The neutron beam and proton target were alternately polarized for the measurements of $A_n$ and $A_p.$ A mirror-symmetric detection system was used to cancel geometry-related systematic errors. From fits of the measured asymmetry angular distributions over the range of $53.4°<~{\theta }_{\mathrm{cm}}<~86.9°,$ the difference in the zero-crossing angles of the analyzing powers was determined to be $0.438°\pm 0.054°(\mathrm{stat}.\mathrm{})\pm 0.051°(\mathrm{syst}.\mathrm{})$ in the center-of-mass system. Using the experimentally determined slope of the analyzing power $dA/d\theta =(-1.35\pm 0.05)\times {10}^{-2}$ ${\mathrm{deg}}^{-1}$ (c.m.), this is equivalent to $\Delta A\equiv A_n-A_p=[59\pm 7(\mathrm{stat}.\mathrm{})\pm 7(\mathrm{syst}.\mathrm{})\pm 2(\mathrm{syst}.\mathrm{}\left)\right]\times {10}^{-4}.$ The shape of $\Delta A\left(\theta \right)$ in the vicinity of the zero-crossing angle has also been extracted. Predictions of nucleon-nucleon interaction models based on meson exchange agree well with the results.

We study elastic $N\alpha$ scattering and produce a quantitative correlation between the range of the effective potential and the energy of the system. This allows the identification of the waves and energies for which the scattering may be said to be peripheral. We then show that the corresponding phase shifts are sensitive to the tail of the $\mathrm{NN}$ potential, which is due to the exchange of two pions. However, the present uncertainties in the experimental phase shifts prevent the use of $N\alpha$ scattering to discriminate the existing models for the $\mathrm{NN}$ interaction.

A previously developed Poincaré invariant, front form model of the pion-nucleon system is extended up to a pion lab kinetic energy of 1.0 GeV, which corresponds to a total c.m. energy of 1.74 GeV. The model is constructed in a space spanned by single baryon states $|B〉$, where $B$ is the nucleon, or any resonance that contributes in the energy range considered, and by meson-baryon states $|\mu B〉$ where $|\mu B〉=|\pi N〉$, $|\pi \Delta 〉$, or $|\eta N〉$. The model specifies a mass-square operator in the form $M^2{=M}_0^2+V$ where $M_0$ is a noninteracting mass operator and $V$ is an interaction. The $\mu B-{\mu }^{\prime }{B}^{\prime }$ interactions are assumed to be separable.

We have measured the parallel momentum distributions of outcoming fragments in the one-neutron breakup of the odd-mass carbon isotopes ${}^{19,17,15}\mathrm{C}$ and ${}^{14}\mathrm{B}$. Owing to their low neutron separation energies, the study of these nuclei is of particular interest regarding the appearance of the halo phenomenon. Discrepancies between experiment and theory observed for ${}^{15}\mathrm{C}$ and ${}^{14}\mathrm{B}$ indicate that their halos are not as prominent as in ${}^{11}$Be or ${}^{11}$Li, and that core excitations start playing a role in the breakup mechanism. In ${}^{17}\mathrm{C}$ the halo appears hindered by a $d$-wave neutron ground state configuration. Finally, the data on ${}^{19}\mathrm{C}$ suggests an $s$-wave neutron around the 2${}^{+}$ excited state in ${}^{18}\mathrm{C}$.

We report on measurements of quadrupole-interaction-resolved nuclear magnetic resonance on oriented nuclei (QI-NMR-ON) of ${9/2}^{+}$ ${}^{185}\mathrm{Pt}$ ${(T}_{1/2}=1.2\mathrm{h})$, ${3/2}^{-}$ ${}^{189}\mathrm{Pt}$ ${(T}_{1/2}=10.9\mathrm{h}),$ and ${3/2}^{-}$ ${}^{191}\mathrm{Pt}$ ${(T}_{1/2}=2.9\mathrm{d})$ in hcp-Co. Ratios of quadrupole moments were determined to be ${Q(}^{185}\mathrm{Pt}{)/Q(}^{191}\mathrm{Pt})=-4.46(13)\mathrm{}$ and ${Q(}^{189}\mathrm{Pt}{)/Q(}^{191}\mathrm{Pt})=+1.235\mathrm{}(8)\mathrm{}$.

High-spin states have been populated in ${}^{156}\mathrm{Ho}$ with the ${}^{14}{\mathrm{N}+}^{148}\mathrm{Nd}$ reaction at 96 MeV. The known level scheme has been considerably extended using the Gammasphere spectrometer. Configuration assignments for these bands have been deduced from their aligned angular momenta, signature splittings and from a systematic survey of the neighboring nuclei and these are compared with theoretical $B\left(M1\mathrm{}\right)/B\left(E2\mathrm{}\right)\mathrm{}$ predictions from a semiclassical model. Evidence is also presented for the onset of band termination, or the beginning of a prolate collective to oblate noncollective shape change near the yrast line, at the highest spin states in two of the observed strongly coupled bands.

Projectile excitation and the transient field technique have been used to measure the $g$ factors of the 2${}_1^{+},$ 2${}_2^{+},$ and 4${}_1^{+}$ states in ${}^{74–82}$Se in order to study the influence of the $N=50\mathrm{}$ shell closure at low excitation energies. The states of interest were populated by Coulomb exciting beams of the appropriate isotope by the same natural Si target. The results demonstrate that inverse kinematics provides a very powerful technique, highly suitable for measurements with radioactive beams. The $g$ factors obtained for ${}^{74–82}$Se are compared with results from IBM-II calculations.

Mean lifetimes of states in ${}^{86}\mathrm{Nb}$ and ${}^{86}\mathrm{Zr}$ produced by the ${}^{58}\mathrm{Ni}{(}^{32}\mathrm{S}{,3pn)}^{86}\mathrm{Nb}$ and ${}^{58}\mathrm{Ni}{(}^{32}\mathrm{S}{,4p)}^{86}\mathrm{Zr}$ reactions at 130 MeV have been measured using the recoil-distance method. The $B\left(E2\mathrm{}\right)\mathrm{}$ strength of 11(2) W.u. for the $8^{+}\to 6^{+}$ transition in ${}^{86}\mathrm{Nb}$ implies weak collectivity at low excitation energies for the $\pi =+\mathrm{yrast}$ band. The weak dipole transition strength of the $8^{+}\to 7$ decay suggests that the configuration for the $7ħ$ state is different from that of the other yrast states. In general, the $B\left(E2\mathrm{}\right)\mathrm{}$ rates obtained for transitions in ${}^{86}\mathrm{Zr}$ agree with those previously published, thus supporting the suggestion of a weakly collective structure based on shell-model excitations at low energies. Hartree-Fock-Bogolyubov cranking calculations indicate a spherical shape for low-spin vacuum configuration states in ${}^{86}\mathrm{Zr}$.

Eight superdeformed bands have been observed in the nuclei ${}^{147,148}\mathrm{Eu}.$ Some of these are identical to bands in the $Z+1\mathrm{}$ nuclei ${}^{148,149}\mathrm{Gd},$ and are interpreted as having the same single-particle configurations with the exception of a hole in one of the $\left[301\right]1/2$ proton orbitals. Some of the bands in ${}^{147}\mathrm{Eu}$ exhibit either upbends or downbends in their moments of inertia which are related to the crossing of $\pi 6^1$ and $\pi 6^3$ proton intruder configurations. These results constitute the first evidence of this crossing.

Spin polarization $P>\mathrm{}1\%$ has been observed for ${}^{37}\mathrm{K}$ fragments produced in the reaction ${}^{40}\mathrm{Ca}{+}^9\mathrm{Be}$ at 500 MeV/nucleon. The polarization was measured as a function of fragment longitudinal momentum (Goldhaber distribution). The experimental results are well described by a new Monte Carlo–based model. The $\beta$-decay half-life of ${}^{35}\mathrm{K}$ was remeasured as $t_{1/2}=178\mathrm{}\left(8\right)\mathrm{}$ ms. Using polarized ${}^{35}\mathrm{K}$ fragments, the $g$ factor $g_{\exp }{(}^{35}\mathrm{K})=0.24\mathrm{}(2)\mathrm{}$ was measured. The magnetic moments of isospin $|T_z|=3/2\mathrm{}$ mirror pairs are discussed.

The odd-proton nuclei ${}^{127}\mathrm{Pr}$ and ${}^{131}\mathrm{Pm}$ have been investigated using the ${}^{96}\mathrm{Ru}{(}^{35}\mathrm{Cl},2p2n)$ and ${}^{96}\mathrm{Ru}{(}^{40}\mathrm{Ca},\alpha {p)/}^{96}\mathrm{Ru}{(}^{39}\mathrm{K},2p2n)$ reactions, respectively, at beam energies of 164, 180, and 186 MeV. States belonging to the yrast bands of ${}^{127}\mathrm{Pr}$ and ${}^{131}\mathrm{Pm}$, which are interpreted as being based upon the $h_{11/2}$ $\left[541\right]{\frac{3}{2}}^{-}$ proton configuration, have been observed from the ${\frac{11}{2}}^{-}$ band head to spin ${\frac{47}{2}}^{-}.$ The properties of these two new structures are observed to be different to those of similar configurations in the heavier odd mass isotopes. The systematics of the band crossings in the $\pi h_{11/2}$ bands of the odd mass Pr and Pm isotopes are discussed and compared with extended total Routhian surface calculations.

A search for proton decay from a predicted ${\frac{19}{2}}^{-}$ isomer of ${}^{77}\mathrm{Rb}$ has been performed. Products of the ${}^{40}{\mathrm{C}\mathrm{a}+}^{40}\mathrm{Ca}$ reaction at average laboratory bombardment energies of 145 and 160 MeV were transported by a helium jet to an array of particle-identification telescopes. No evidence of proton emission from the predicted isomer was observed. In a second measurement, mass 77 residues of the ${}^{40}{\mathrm{C}\mathrm{a}+}^{\mathrm{nat}}\mathrm{Ca}$ reaction at an average laboratory bombardment energy of 132 MeV were separated using the on-line mass separator RAMA. The yields of ${}^{77}\mathrm{Rb}$ and ${}^{77}\mathrm{Sr}$ were monitored by observation of beta-delayed gamma rays; $1.6\times {10}^6$ atoms of ${}^{77}\mathrm{Rb}$ were transported to the detectors. A single particle-identification telescope subtending 23% of 4π sr again showed no evidence of proton emission from the predicted isomer.