We present results for quark cluster probabilities in nuclei based on the assumptions of the quark cluster model. We first perform numerical evaluations in a=2, 3, and 4 nuclei based on realistic nuclear wave functions for the probability that a quark chosen at random in the nucleus is found in a color singlet cluster consisting of 3, 6, 9, etc., quarks. Clustering itself is determined by a geometrical overlap of three-quark systems that depends on a critical distance of separation 2$R_c$. A systematic comparison of cluster probabilities obtained for these light nuclei establishes certain features of these results, which are independent of A and of the wave function used. These results are then used to make predictions of quark cluster probabilities in heavier nuclei. We present relationships between our definition of quark cluster probabilities and that of some other efforts.

We discuss the quantum chromodynamically motivated color-dielectric model originally proposed by Nielsen and Patkos and show, using some straightforward approximations, that it can lead to charge-symmetry breaking effects in nuclei. We then show, using a local density approximation and standard nuclear structure properties, that for suitable choices of parameters this color-dielectric model can explain the Nolen-Schiffer anomaly.

Using new theoretical values for the ionization probabilities during the incoming part of a collision, we have reanalyzed the mean nuclear level widths obtained by the particle-x-ray coincidence method. We find that the deduced level widths are substantially reduced.

Cross sections at theta=5° (lab) were obtained at seven energies for ${}_{}{}^{14}{}_{}{}^{}\mathrm{C}$(${\pi }^{+}$,${\pi }^{\mathrm{-}}$)${}^{14}$ O(g.s.) and at four energies for ${}_{}{}^{26}{}_{}{}^{}\mathrm{Mg}$(${\pi }^{+}$,${\pi }^{\mathrm{-}}$)${}^{26}$ Si(g.s.). Angular distributions have been measured for both reactions at energies of 140 and 200 MeV. The results are compared to previous angular distributions at other energies on these two nuclei, and to a series of angular distributions measured for ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$(${\pi }^{+}$,${\pi }^{\mathrm{-}}$).

It is shown that a two-state model in which two neutron and alpha transfer amplitude ratios vary linearly with mass leads to solutions for $0_1^{+}$ and $0_2^{+}$ states in Ge isotopes which give consistent agreement with experimental data. The corresponding energy gap between basis states decreases linearly with increasing neutron number, suggesting that these states differ mainly by proton excitation.

Calculations of elastic and inelastic photon scattering at energies around the giant dipole resonance are carried out for osmium isotopes in the SU(3)→O(6) transitional region of the interacting boson model. ${}_{}{}^{186}{}_{}{}^{}\mathrm{Os}$ shows features of a prolate nucleus, ${}_{}{}^{188–192}{}_{}{}^{}\mathrm{Os}$ that of γ-soft nuclei.

It is noted that one requires a very small admixture of the breathing mode state (1$s_{1/2}$0$s_{1/2}^{\mathrm{-}1}$${)}^{J=0\mathrm{}}$ in the 20.1 MeV $0^{+}$ first excited state of ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ in order to explain the results of recent inelastic scattering experiments. This lends support to our previous work in which it was noted that two- and four-particle excitation into a deformed p shell could account for the low-lying positive parity excited states.

The experimental trend of the effective radii of composite particles emitted from a hot source in relativistic heavy ion collisions at different beam energies is qualitatively reproduced by solving a Bethe-Goldstone–type equation in a perturbative way for a deuteron embedded in a hot nuclear medium.

It is shown that the results of a recent paper on the polarization structure of reactions of the type (1/2)+(1/2)→1+0 (and of the reaction p+p→d+π in particular) can be easily transferred to the reaction of the type (1/2)+1→(1/2)+0. The substitutions needed for the transfer are specified, and then conclusions are presented concerning the maximally informative experimental program of polarization experiments exploring such a reaction and, in particular, the reaction p+d→t+π. .AE

The law σ=${\sigma }_0$$A^{\nu }$, with ν≃0.6, proposed recently by Ashford et al. for the absorption cross sections of antiprotons on nuclei, brings up the question of the blackness of nuclei for antiprotons. The absorption cross sections on several nuclei at low momenta are fitted by the application of a boundary condition. It is found that complete absorption entails ν=(2/3) only for much higher momenta.

The exact boson mappings for the neutron (proton) p shell recently developed by Bonatsos and Klein are shown to exhibit Sp(6)⊃SU(3) symmetry rather than SO(7)⊃SU(3) symmetry.

The conclusion of McNeil and Shephard that the effect of recent relativistic nuclear models are small in $0^{+}$⇄$0^{\mathrm{-}}$ weak transitions is wrong. We also show that, if we adopt the partial conservation of axial current hypothesis for the nuclear current, the result of a recent calculation for the muon transition ${}_{}{}^{16}{}_{}{}^{}\mathrm{}_{}^{16}{}_{}{}^{}$N(0 -) is changed appreciably.

We agree with the Comment of Rood that $0^{+}$⇄$0^{\mathrm{-}}$ weak processes are sensitive to relativistic nuclear dynamics.

ΔJ=1 band structures were found in the doubly odd ${}_{}{}^{120}{}_{}{}^{}$,122Cs and ${}_{}{}^{126}{}_{}{}^{}$,128La nuclei via γ-ray spectroscopy following heavy-ion-induced reactions. The band characteristics for the Z>50 transition region (non-staggered spacings and positive E2/M1 mixing ratios), that are associated with the $g_{9/2}$ proton-hole intruder, were observed in ${}_{}{}^{120}{}_{}{}^{}\mathrm{Cs}$, but changed to significant staggering and negative mixing ratios along with increased E2 crossover branching in the other three nuclei.

High multiplicity collisions of 1.2 GeV/nucleon ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ar}$ on Kcl and on ${\mathrm{BaI}}_2$ in the Bevalac streamer chamber are studied using the global transverse momentum analysis introduced by Danielewicz and Odyniec. For both systems, there is a sideward flow which is significantly larger than intranuclear cascade model predictions. The current results permit a study of trends in the multiplicity, mass and energy dependence of the observed flow signatures. Estimates of the stiffness of the nuclear equation of state at high density are discussed.

Differential cross sections for inelastic α scattering from ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$ in the region of 10–20 MeV excitation have been measured at $E_{\alpha }$=120 MeV in the angular range of 0–8°. The strength distribution for isoscalar monopole and dipole strength in ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$ between 11–20 MeV was determined. 90±20% of the E0 energy-weighted sum rule and 56±12% of the E1, ΔT=0 energy-weighted sum rule are found to be exhausted in this excitation energy region.

Electron-nucleus elastic scattering is calculated by means of the multiple scattering series of Glauber theory and by means of the eikonal approximation applied to a nuclear charge distribution. The differences between the resulting cross sections are examined for a wide variety of nuclei and over a large range of momentum transfers.

We report high resolution measurements of inelastic electron scattering to all narrow normal-parity states of ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ up to 12.05 MeV, which include states with $J_n^{\pi }$($E_x$ MeV): $0_2^{+}$(6.049), $0_3^{+}$(12.049), $1_1^{\mathrm{-}}$(7.117), $2_1^{+}$(6.917), $2_2^{+}$(9.845), $2_3^{+}$(11.52), $3_1^{\mathrm{-}}$(6.130), $4_1^{+}$(10.356), and $4_2^{+}$(11.097). The measurements were performed primarily at 90° and 160° and span momentum transfers between 0.6 and 2.6 ${\mathrm{fm}}^{\mathrm{-}1}$. Improved line shape fitting techniques have been developed. These are the first electron scattering measurements for the $4_2^{+}$ state and of second form-factor maxima for several states. The form factor for excitation of the $2_2^{+}$ state is strikingly different from that of the other $2^{+}$ states and indicates a transition density peaked in the interior. Transition charge densities were extracted from a combined data set that includes earlier electron scattering data renormalized to a recent analysis of elastic scattering from ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$. Comparisons have been made with several structure models, including the Brown-Green model, the weak-coupling model, a 2ħω shell model, and the tetrahedral alpha-cluster model.