The nuclear structure of ${}_{}{}^{96}{}_{}{}^{}\mathrm{Nb}$ has been studied with the ($\mathrm{t},\alpha$) reaction at 17 MeV on an isotopically enriched target of ${}_{}{}^{97}{}_{}{}^{}\mathrm{Mo}$ using a quadrupole-three-dipole spectrometer. Measured angular distributions were compared with distorted-wave Born approximation calculations to assign $l$ transfer values. The results are combined with published data and shell model considerations to reassign the $3^{-}$ state of the low-lying $\pi {\left(p\frac{1}{2}\right)}^1\nu {\left(d\frac{5}{2}\right)}^{-1\mathrm{}}$ configuration and to confirm the assignments of the spins and parities of the other levels observed.

[NUCLEAR REACTIONS ${}_{}{}^{97}{}_{}{}^{}\mathrm{Mo}(\mathrm{t},\alpha ){}_{}{}^{96}{}_{}{}^{}\mathrm{Nb}$, $E_t=17\mathrm{}$ MeV, enriched target; measured $E_{\alpha },\sigma \left(\theta \right)$. DWBA analysis. ${}_{}{}^{96}{}_{}{}^{}\mathrm{Nb}$ deduced levels, $J^{\pi }$. Compared ${}_{}{}^{96}{}_{}{}^{}\mathrm{Nb}$ and ${}_{}{}^{92}{}_{}{}^{}\mathrm{Nb}$ using Pandya relation.]

The cross section, analyzing power, and spin-flip probability have been measured for the $M1\mathrm{}$ transition at 10.23 MeV excitation energy in the ${}_{}{}^{48}{}_{}{}^{}\mathrm{Ca}(\overrightarrow{\mathrm{p}},{\overrightarrow{\mathrm{p}}}^{\prime }){}_{}{}^{48}{}_{}{}^{}\mathrm{Ca}_{}^{*}{}_{}{}^{}$ reaction at 319 MeV between 2.75° and 5.75°. The data are in good agreement with distorted-wave impulse approximation calculations; about 28% of the pure single particle $(\nu f_{\frac{7}{2}}^{}{}_{}{}^{-1\mathrm{}},f_{\frac{5}{2}})M1\mathrm{}$ strength is observed. The results serve as a good calibration of results expected in heavy nuclei.

The widths of the isovector monopole excitations in ${}_{}{}^{90}{}_{}{}^{}\mathrm{Y}$ and ${}_{}{}^{208}{}_{}{}^{}\mathrm{Tl}$ have been calculated in a microscopic model including two-particle two-hole excitations. As a consistency check of the model we demonstrate that the isobaric analog states in ${}_{}{}^{90}{}_{}{}^{}\mathrm{Nb}$ and ${}_{}{}^{208}{}_{}{}^{}\mathrm{Bi}$ have negligible width.

[NUCLEAR STRUCTURE ${}_{}{}^{90}{}_{}{}^{}\mathrm{Zr}$, ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$; microscopic calculation of strength functions for charge exchange. Fragmentation of isovector monopole modes. Two-particle two-hole states included.]

We use sum rules to calculate the zeroth moment of photoeffect for a central nucleon-nucleon potential with Serber exchange. We explore the consequence of using the full potential on this moment, and hence on the variation of cross section with the incident photon energy. The results are compared with recent experimental observations.

[NUCLEAR REACTIONS Alpha particle, hyperspherical harmonics, moments of photoeffect, sum rule.]

The rate for the excitation of stretched states in a deformed model can be considerably smaller than in the single particle model. In one specific case, and in an approximation in which rotational currents are neglected, the two rates differ by a factor of $\frac{\mathrm{}(2J+1)\mathrm{}}{2}$, where $J$ is the angular momentum of the stretched states. Thus, as has been noted by Amusa and Lawson, nuclear structure effects can explain all or a large part of the observed quenching.

[NUCLEAR STRUCTURE The calculation of the transition rates to stretched states, e.g., $6^{-}$ state in ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$, using a deformed model and comparing this with the single particle model.]

A new effective range formula is developed using conformal mapping techniques. In contrast to earlier attempts in this direction, our formula is valid for arbitrary high energies and for all processes. As an illustration we study the $s$ wave in np scattering.

[NUCLEAR REACTIONS Scattering theory, effective range expansion, np scattering, $E=1-80\mathrm{}$ MeV.

The sensitivity of inclusive observables in heavy ion collisions to the nuclear equation of state can be tested with the Boltzmann equation. We solve the Boltzmann equation, including mean field and Pauli blocking effects, by a method that follows closely the cascade model. We find that the inclusive pion production is insensitive to the nuclear equation of state, contrary to recent claims.

A ${}_{}{}^9{}_{}{}^{}\mathrm{Be}$(p,pd) coincidence experiment performed to further elucidate the reaction mechanism for the production of energetic wide angle ejectiles in intermediate energy proton induced reactions is reported. Plastic-NaI detector telescopes in a coplanar geometry were used to measure coincidences between deuterons at 90° to the beam and forward angle protons on the opposite side of the beam. The incident proton energy was 300 MeV. Differential mean multiplicities for the coincidence events are presented, with the deuteron energies grouped into 10 MeV bins covering the kinetic energy range from 55 to 115 MeV. Forward protons were measured over a kinetic energy range of 65-280 MeV and an angular range of 14°-60° with respect to the beam. Consequences for the interpretation of wide angle emission of composite ejectiles in proton induced reactions are discussed.

[NUCLEAR REACTIONS ${}_{}{}^9{}_{}{}^{}\mathrm{Be}$(p,pd), $E=300\mathrm{}$ MeV, ${\theta }_{\mathrm{d}}=90\mathrm{}°$; measured p,d angular correlations, deduced differential mean multiplicities.]

The strong model dependence of Coulomb-corrected scattering lengths is exhibited within the frame-work of local strong interaction potentials. The technique of short range expansions offers a simple formula for their computation.

Binding energies of hypernuclei are calculated with use of accurate variational methods for $A=3,5\mathrm{}$, with effective interaction calculations for $A=5,9,13,\infty$, and with Fermi hypernetted-chain variational calculations for $A=\infty$. Effective interactions and variational results agree within a few percent. For $\Lambda N$ forces consistent with $\Lambda \mathrm{p}$ scattering, agreement with the experimental energies is obtained with strongly repulsive Wigner type $\Lambda \mathrm{NN}$ forces, and for $A>\mathrm{}5\mathrm{}$ also with a weakened $p$-state $\Lambda \mathrm{N}$ strength about half that of the $s$-state strength.

By fitting low-lying energy spectra of the samarium isotopes an effective boson Hamiltonian was found which is explicitly boson-number independent. The quadrupole moment and transition properties can be reproduced well only if the effective charge $\alpha$ is varied with boson number.

[NUCLEAR STRUCTURE IBA model, even-even Sm isotopes, $A=148-158\mathrm{}$.]

We investigate effects of the up-down quark mass difference on the couplings of pions to nucleons or isobars. The calculated $\pi \mathrm{NN}$ and $\pi \mathrm{N}\Delta$ couplings are used to derive the long-range one-pion-exchange potential and the intermediate-range attraction for the three different cases: p-p, n-p, and n-n. The resultant potentials are then used to determine numerically the low-energy scattering parameters, including both the scattering length $a$ and the effective range $r$. Our results indicate that a reasonable up-down quark mass difference such as 10 MeV yields a value for $\left|a_{\mathrm{pp}}\mathrm{}\right|-\left|\mathrm{}{a}_{\mathrm{nn}}\right|$ of about + 0.6 fm, which is sizable from the experimental point of view. Our results also suggest that the large observed value for $\left|a_{\mathrm{np}}\mathrm{}\right|-\left|\mathrm{}{a}_{\mathrm{nn}}\right|$ can be understood primarily as a manifestation of the pion mass difference.

[NUCLEAR REACTIONS Application of quark models to nuclear physics; effects of the up-down quark mass difference on couplings of pions to nucleons or isobars; charge dependence and charge symmetry breaking in low energy nucleon-nucleon scattering.]

The exciton coalescence model is extended to include second chance emission during the preequilibrium phase. The extended model allows the calculation of the parts of the cross sections associated with large linear momentum transfer. Under the assumption that the linear momentum dissipation is independent of the linear momentum carried away by the first emitted particle, coincident spectra may be calculated. The model predictions are compared to data.

[NUCLEAR REACTIONS ${}_{}{}^{197}{}_{}{}^{}\mathrm{Au}(\mathrm{p},{\mathrm{p}}^{\prime })X$, $E=200\mathrm{}$ MeV; ${}_{}{}^{58}{}_{}{}^{}\mathrm{Ni}(\alpha ,{\alpha }^{\prime }\mathrm{p})$, $E=140\mathrm{}$ MeV, calculated cross sections, model for coincident light ion emission.]

Rotational bands in the odd-odd nucleus, ${}_{}{}^{182}{}_{}{}^{}\mathrm{Re}$, have been studied via the ${}_{}{}^{181}{}_{}{}^{}\mathrm{Ta}(\alpha ,3\mathrm{}\mathrm{n}\gamma ){}_{}{}^{182}{}_{}{}^{}\mathrm{Re}$, ${}_{}{}^{182}{}_{}{}^{}\mathrm{W}(\mathrm{p},\mathrm{n}\gamma ){}_{}{}^{182}{}_{}{}^{}\mathrm{Re}$, and ${}_{}{}^{184}{}_{}{}^{}\mathrm{W}(\mathrm{p},3\mathrm{}\mathrm{n}\gamma ){}_{}{}^{182}{}_{}{}^{}\mathrm{Re}$ reactions, using Ge $\gamma$-ray detectors in a variety of singles, coincidence, delayed coincidence, and angular distribution experiments. Four rotational bands were characterized extensively: $7^{+}\left\{\pi {\frac{5}{2}}^{+}\right[402\mathrm{}\uparrow ]\otimes \nu {\frac{9}{2}}^{+}[624\mathrm{}\uparrow \left]\right\}$, triplet coupling ($64-\mathrm{h} {}_{}{}^{182}{}_{}{}^{}\mathrm{Re}_{}^g{}_{}{}^{}$) to $J=16\mathrm{}$; $2^{+}$, singlet coupling ($12.7-\mathrm{h} {}_{}{}^{182}{}_{}{}^{}\mathrm{Re}_{}^m{}_{}{}^{}$), to $J=12\mathrm{}$; $9^{-}\left\{\pi {\frac{9}{2}}^{-}\right[514\mathrm{}\uparrow ]\otimes \nu {\frac{9}{2}}^{+}[624\mathrm{}\uparrow \left]\right\}$, triplet band head ($t_{\frac{1}{2}}=6\mathrm{}\pm 2$ ns) at 443.1 keV, to $J=15\mathrm{}$; and $4^{-}\left\{\pi {\frac{1}{2}}^{-}\right[541\mathrm{}\uparrow ]\otimes \nu {\frac{9}{2}}^{+}[624\mathrm{}\uparrow \left]\right\}$, triplet band head ($t_{\frac{1}{2}}=780\mathrm{}\pm 90$ ns) at 461.3 keV above ${}_{}{}^{182}{}_{}{}^{}\mathrm{Re}_{}^m{}_{}{}^{}$. All four bands are highly distorted from Coriolis effects. $g_K$ and $g_R$ were deduced and agree with the assigned configurations. A four-quasiparticle isomer ($t_{\frac{1}{2}}=88\mathrm{}\pm 8$ ns) was located at 2256.3 keV and is characterized as an oblate girdle about the basic prolate core.

[NUCLEAR REACTIONS ${}_{}{}^{181}{}_{}{}^{}\mathrm{Ta}(\alpha ,3\mathrm{}\mathrm{n}\gamma ){}_{}{}^{182}{}_{}{}^{}\mathrm{Re}$, ${}_{}{}^{182}{}_{}{}^{}\mathrm{W}(\mathrm{p},\mathrm{n}\gamma ){}_{}{}^{182}{}_{}{}^{}\mathrm{Re}$, ${}_{}{}^{184}{}_{}{}^{}\mathrm{W}(\mathrm{p},3\mathrm{}\mathrm{n}\gamma ){}_{}{}^{182}{}_{}{}^{}\mathrm{Re}$; $\gamma$-ray singles, $\gamma -\gamma$ coin, delayed coin, $\gamma -\theta$; Ge detectors; determined $E_{\gamma }$, $I_{\gamma }$, $I_{\gamma }\left(\theta \right)$, $g_K$, $g_R$; deduced states in odd-odd ${}_{}{}^{182}{}_{}{}^{}\mathrm{Re}$, $J^{\pi }$, $K$, $t_{\frac{1}{2}}$; calculated rotational band parameters, Coriolis effects, isomer configuration.]

The differential cross sections and the analyzing powers were measured for the ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}(\overrightarrow{\mathrm{p}},\mathrm{d}){}_{}{}^{23}{}_{}{}^{}\mathrm{Mg}$ reaction at 65 and 80 MeV. Adiabatic model and distorted-wave Born approximation calculations were performed for the transitions to the ${\frac{5}{2}}^{+}$, 0.45 MeV, the ${\frac{1}{2}}^{+}$, 2.36 MeV, and the ${\mathrm{½}}^{+}$, 4.36 MeV states. Analyses were also performed for the published data at incident energies of 33.6 and 94.8 MeV. The adiabatic approximation with the nonlocal correction could reproduce the experimental data with the same quality over the whole energy region investigated. The nonlocal correction was important to reproduce the pronounced oscillation of the experimental $l=0\mathrm{}$ analyzing powers. The extracted spectroscopic factors are consistent with the theoretical predictions for both the ${\frac{5}{2}}^{+}$ and the ${\frac{1}{2}}^{+}$ states.

[NUCLEAR REACTIONS ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}(\overrightarrow{\mathrm{p}},\mathrm{d})$, $E=65,80\mathrm{}$ MeV; measured $\sigma \left(\theta \right)$, $A\left(\theta \right)$. Enriched target. Adiabatic model and DWBA analyses.]

The sequential emission and then decay of particle unstable resonances (such as ${}_{}{}^2{}_{}{}^{}\mathrm{He}$) from compound nuclei is discussed. Calculations (based on a statistical model) of yields and energy spectra for the final stable products are presented. The effect of this sequential decay process on coincidence measurements is discussed.

A mechanism is examined for proton yields from heavy-ion reactions. This consists of two components—one direct, and one involving evaporation—and incorporates Coulomb focusing and shadowing effects. Double differential cross sections, with one free normalization parameter, are compared with published data for ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ induced reactions at 310 MeV incident energy on targets of ${}_{}{}^{27}{}_{}{}^{}\mathrm{Al}$, ${}_{}{}^{90}{}_{}{}^{}\mathrm{Zr}$, and ${}_{}{}^{197}{}_{}{}^{}\mathrm{Au}$. The competition between the direct and the evaporation components at different energies and angles is studied with the extracted normalization factor.

Seven elastic scattering angular distributions have been measured for the system ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ + ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$ around the first resonant structure observed in the ${\theta }_{\mathrm{c}.\mathrm{m}.\mathrm{}}=180\mathrm{}°$ excitation function at 21.1 MeV center of mass energy just above the Coulomb barrier. Optical model, Regge pole, and phase shift analyses have been performed. These complementary analyses show that several partial waves contribute to the backward rise and the oscillatory behavior of the elastic scattering angular distributions. The 21.1 MeV resonant structure can be interpreted in terms of several overlapping resonances. Tentative spin assignments are made for these states.

[NUCLEAR REACTIONS Elastic scattering of ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$(${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$). Seven angular distributions measured between 18.67 and 22.29 MeV, angular range 25° to 176° c.m. Optical model, Regge pole, and phase shift analyses.]