Recent Articles

Erratum: Scattering and reaction dynamics for the ${}^{12}C$ + $p$ system

J. R. Comfort and B. C. Karp

Phys. Rev. C 22, 1809 (1980) - Published 1 October, 1980

Erratum: Electroexcitation of ${}^{6}{Li}$ with application to the reactions ${}^{6}{Li} {(π^{-}, γ)}_{1 s}$ ${}^{6}{He}$ ( $0^{+}$ , $2^{+}$ )

J. C. Bergstrom

Phys. Rev. C 22, 1809 (1980) - Published 1 October, 1980

Pre-equilibrium process for ${}^{175}{Lu} (p, xn γ)$ , ${}^{176}{Yb} ({}^{3}{He}, xn yp γ)$ , and ${}^{174, 176}{Yb} (α, xn γ)$ reactions

H. Sakai, A. Shimizu, H. Ejiri, T. Shibata, K. Okada, T. Kishimoto, and K. Maeda

Phys. Rev. C 22, 1002 (1980) - Published 1 September, 1980

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The pre-equilibrium deexcitation process for (particle, $xn yp γ$ ) reactions induced by medium energy (40-120 MeV) light ions was studied by measuring singles $γ$ -ray spectrum. The neutron multiplicity $x$ following these reactions was identified by discrete $γ$ rays characteristic of the (particle, $xn yp γ$ ) reaction residues. The neutron multiplicity distribution was found to depend on the projectile mass number. It suggests that the decaying neutrons depend on the initial exciton number at the pre-equilibrium phase. The median spin $I_{m}$ of the yrast levels populated by the (particle, $xn yp$ ) reactions was found to be nearly constant in a wide range of the bombarding energy. The $K$ -isomer population ratio for the ${}^{172}{Hf}$ and ${}^{174}{Hf}$ depends on the projectile mass. The neutron multiplicity distribution was analyzed in terms of a simple two phase deexcitation model. The pre-equilibrium temperature, the number of particles emitted at the pre-equilibrium phase, and the exciton particle number at the preequilibrium phase (local mass) were deduced.

NUCLEAR REACTIONS ${}^{175}{Lu} (p, x n)$ , $x = 2 - 5$ , $E = 40$ MeV; ${}^{176}{Yb} ({}^{3}{He}, xn y p)$ $x = 5 - 11$ , $y = 0 - 1$ , $E = 65 - 100$ MeV; ${}^{174, 176}{Yb} (α, x n)$ , $x = 2 - 11$ , $E = 50 - 120$ MeV; measured $E_{γ}$ , $I_{γ}$ ; deduced median spin values, $K$ -isomer population ratio. Enriched targets, HPGe, Ge(Li) detectors. Two phase deexcitation model analysis.

Electrodisintegration of ${}^{58}{Ni}$ , ${}^{60}{Ni}$ , and ${}^{62}{Ni}$

E. Wolynec, W. R. Dodge, R. G. Leicht, and E. Hayward

Phys. Rev. C 22, 1012 (1980) - Published 1 September, 1980

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The ( $e, p$ ) and ( $e, α$ ) cross sections for targets of ${}^{58}{Ni}$ , ${}^{60}{Ni}$ , and ${}^{62}{Ni}$ have been measured in the electron energy range 16-100 MeV. They have been analyzed using the distorted-wave Born approximation $E 1$ and $E 2$ virtual photon spectra. Protons are emitted primarily following $E 1$ absorption but $α$ -emission results from a combination of $E 1$ and $E 2$ absorption.

NUCLEAR REACTIONS ${}^{58, 60, 62}{Ni} (e, p)$ and ${}^{58, 60, 62}{Ni} (e, α)$ ; measured $σ (E_{0}, E_{x}, 48 °)$ , $σ (E_{0}, E_{x}, 90 °)$ , $σ (E_{0}, E_{x}, 132 °)$ , obtained $σ (e, p)$ , $σ (e, α)$ ; deduced $σ_{γ, p}^{E 1} (E)$ , $σ_{γ, α}^{E 1} (E)$ , $σ_{γ, α}^{E 2} (E)$ .

Classical-equations-of-motion calculations of high-energy heavy-ion collisions

A. R. Bodmer, C. N. Panos, and A. D. MacKellar

Phys. Rev. C 22, 1025 (1980) - Published 1 September, 1980

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Results are obtained with the classical-equations-of-motion approach which provides a complete microscopic, classical, description including finite-range interaction effects. Nonrelativistic classical-equations-of-motion calculations are made for equal mass projectile and target nuclei with $A_{P} = A_{T} = 20$ (Ne + Ne) at laboratory energies per projectile nucleon of $E_{L} = 117, 400, and 800$ MeV and at 400 MeV for $A_{P} = A_{T} = 40$ (Ca + Ca). A static two-body potential $V_{st}$ is used which is fitted to $σ^{(2)}$ , the ${sin}^{2} θ$ weighted differential cross section. For $A_{P} = A_{T} = 20$ we also use a scattering equivalent momentum dependent potential $V_{tr}$ . $V_{st}$ and $V_{tr}$ give identical two-body scattering but are not equivalent for many-body scattering and are used to test for finite-range interaction effects in heavy-ion collisions. The evolution of central collisions is discussed. For these multiple scattering is large leading to high momentum components. Dissipation quite generally is larger at lower energies and is appreciable during the expansion phase of central collisions giving approximately thermalized distributions at the lower $E_{L}$ . A peak at approximately the same momentum at all angles develops in the momentum distribution near the beginning of the expansion and changes roughly in step with the potential energy; for $A_{P} = A_{T} = 20$ at 800 MeV the peak persists to the final distributions. There are very appreciable differences in the densities, potential energies, and distributions between $V_{st}$ and $V_{tr}$ during the strong interaction stage. However, the final distributions are not significantly different even for $A_{P} = A_{T} = 20$ at 800 MeV. For $A_{P} = A_{T} = 40$ at 400 MeV a transverse peaking develops in the momentum distribution suggestive of collective effects. Noncentral collisions show typical nonequilibrium features and for larger impact parameters the final distributions show a strong single scattering component. This is true also of the impact parameter averaged distributions which are in fair agreement with experiment. A partial test of thermal models is made. Limitations and extensions of the classical-equations-of-motion approach are discussed. In particular we propose a new kinetic equation which includes finite-range interaction effects. Relativistic classical-equations-of-motion calculations to $O (\frac{v^{2}}{c^{2}})$ are briefly discussed.

NUCLEAR REACTIONS Heavy ion (Ne + Ne, Ca + Ca); $laboratory energy / n = 117, 400, 800$ MeV; classical microscopic many-body calculations.

Nucleus-nucleus total reaction cross sections

R. M. DeVries and J. C. Peng

Phys. Rev. C 22, 1055 (1980) - Published 1 September, 1980

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We compare $σ_{R} (E)$ for nucleus-nucleus systems (obtained from existing direct measurements and derived from elastic scattering data) with nucleon-nucleon and nucleon-nucleus data. The energy dependence of $σ_{R} (E)$ for nucleus-nucleus systems is found to be quite rapid; there appears to be no evidence for an energy independent, geometric $σ_{R}$ . Simple parameter free microscopic calculations are able to quantitatively reproduce the data and thus, emphasize the dominance of nucleon-nucleon interactions in medium energy nucleus-nucleus collisions.

NUCLEAR REACTIONS Total reaction cross section theory, comparison to data for $d$ , ${}^{3}{He}$ , $α$ + ${}^{12}C$ , ${}^{40}{Ca}$ , ${}^{90}{Zr}$ , ${}^{208}{Pb}$ and ${}^{12}C$ + ${}^{12}C$ . Predictions for ${}^{40}{Ca}$ + ${}^{40}{Ca}$ , ${}^{40}{Ca}$ + ${}^{208}{Pb}$ , ${}^{208}{Pb}$ + ${}^{208}{Pb}$ . Energy range $3 < E_{\frac{i}{n}} < 1000$ MeV.

Magnetic moments of the $2_{1}^{+}$ levels in ${}^{92}{Zr}$ and ${}^{94}{Zr}$

M. Hass, C. Broude, Y. Niv, and A. Zemel

Phys. Rev. C 22, 1065 (1980) - Published 1 September, 1980

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The $g$ factors of the $2_{1}^{+}$ levels of ${}^{92}{Zr}$ and ${}^{94}{Zr}$ have been measured using the dynamic magnetic field which acts on fast ions traversing a thin magnetized iron foil. The results obtained are $g ({}^{92}{Zr}, 2_{1}^{+}) = - 0.03 \pm 0.05$ and $g ({}^{94}{Zr}, 2_{1}^{+}) = - 0.26 \pm 0.06$ . The present results indicate sizable admixture of components other than $d_{\frac{5}{2}}$ neutrons in the wave functions of these levels.

NUCLEAR REACTIONS ${}^{92, 94}{Zr}$ ( ${}^{35}{Cl}$ , ${}^{35}{Cl}$ ′) ${}^{92, 94}{Zr}$ *( $2_{1}^{+}$ ) $E = 90$ MeV, enriched targets; measured $W (θ, H, \infty)$ ; fast ions in thin polarized iron. Deduced magnetic moments of the $2_{1}^{+}$ levels in ${}^{92, 94}{Zr}$ .

Application of a band-crossing model for resonances in ${}^{16}O$ + ${}^{16}O$ scattering

Yosio Kondō, D. A. Bromley, and Yasuhisa Abe

Phys. Rev. C 22, 1068 (1980) - Published 1 September, 1980

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A band-crossing model that has been proposed as a possible mechanism for resonances in heavy ion reactions is applied to energy dependent structure in the ${}^{16}O$ + ${}^{16}O$ system. The recently observed intermediate-width structure in the 6.13 MeV gamma-radiation yield can be well understood in terms of the band-crossing model, assuming the crossing of the elastic potential resonance band and an aligned rotational band in which the intrinsic spin ( $3 ℏ$ ) and the relative angular momenta are coupled to their maximum value. Numerical calculations based on this model reproduce all of the observed energy dependent structure of the cross section in the ${}^{16}O$ + ${}^{16}O$ interaction, i.e., the gamma-radiation yield from the $3_{1}^{-}$ state of ${}^{16}O$ , as well as the total fusion and elastic scattering data. Each oscillation in the fusion excitation function is interpreted as reflecting a shape resonance of each new grazing partial wave in the entrance channel as it becomes active with increasing energy. The observed anticorrelation of the total fusion and the 90° excitation function of elastic scattering data is reproduced naturally by the model. It is concluded that these data support the existence of nuclear molecular resonances in the ${}^{16}O$ + ${}^{16}O$ system.

NUCLEAR REACTIONS ${}^{16}O$ + ${}^{16}O$ scattering, $10 <~ E_{c . m .} <~ 41$ MeV; calculated elastic scattering excitation functions, fusion cross sections, and $3_{1}^{-}$ inelastic cross sections. Resonance mechanism for heavy ion reactions.

Light-charged-particle emission in ${}^{40}{Ar}$ -induced reactions: A probe of the very early evolution of the collisions

D. Logan, H. Delagrange, M. F. Rivet, M. Rajagopalan, John M. Alexander, Morton Kaplan, M. S. Zisman, and E. Duek

Phys. Rev. C 22, 1080 (1980) - Published 1 September, 1980

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Charged-particle emission was studied for the reactions 222, 274, and 340 MeV ${}^{40}{Ar}$ + ${}^{116}{Sn}$ , ${}^{154}{Sm}$ , ${}^{164}{Dy}$ , and ${}^{197}{Au}$ . Energy and angular distributions were measured for H and He and angular distributions for Li, Be, B, C, N, and O, fissionlike fragments and evaporation residues. For H and He the data are consistent with a lowtemperature evaporative component and a high-temperature forward peaked component. For Li through O the forward-peaked emission was studied for 340 MeV ${}^{40}{Ar}$ only. The evaporation residue cross sections decrease strongly with increasing $Z$ reflecting the increasing fissionability. However, the cross sections for ${}^{1}H$ and ${}^{4}{He}$ in coincidence with fission are essentially constant with $Z$ . Coincidence measurements, energy spectra, and ${}^{4}{He}$ / ${}^{1}H$ ratios indicate that most H/He evaporation precedes fission. This implies that the energy thermalization is very rapid indeed and that the light particle spectra can probe the very early history of the composite systems.

NUCLEAR REACTIONS ${}^{116}{Sn}$ , ${}^{154}{Sm}$ , ${}^{164}{Dy}$ , ${}^{197}{Au}$ ( ${}^{40}{Ar}$ ; H/He, fission and evaporation residues), $E = 222$ , 274, and 340 MeV, measured energy and angular distributions in singles mode. For $E = 340$ MeV, coincidence measurements between H/He and one fission-like fragment, and angular distributions for Li, Be, B, C, N, and O in the singles mode.

Comparison of the single-proton pickup reactions ${}^{40}{Ca}$ ( ${}^{11}B$ , ${}^{12}C$ ) ${}^{39}K$ and ${}^{40}{Ca}$ ( ${}^{13}C$ , ${}^{14}N$ ) ${}^{39}K$ at low and high bombarding energies

C. F. Maguire, G. L. Bomar, A. V. Ramayya, R. B. Piercey, J. L. C. Ford, Jr.,, J. Gomez del Campo, D. Shapira, and D. Hensley

Phys. Rev. C 22, 1097 (1980) - Published 1 September, 1980

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The single-proton pickup reactions ${}^{40}{Ca}$ ( ${}^{11}B$ , ${}^{12}C$ ) ${}^{39}K$ and ${}^{40}{Ca}$ ( ${}^{13}C$ , ${}^{14}N$ ) ${}^{39}K$ are found to produce qualitatively different angular distributions when compared at similar bombarding energies. The surface transparent potential invoked to explain the forward rise in the ${}^{40}{Ca}$ ( ${}^{13}C$ , ${}^{14}N$ ) ${}^{39}K$ differential cross section at 40 MeV is shown to be inappropriate for the ${}^{40}{Ca}$ ( ${}^{11}B$ , ${}^{12}C$ ) ${}^{39}K$ data analysis at 32 MeV incident energy. For the higher energy measurements at 68 MeV, both systems produce oscillatory angular distributions, but in the former case the distorted-wave Born approximation prediction is out of phase with the data, while in the latter it is exactly in phase with the data. The success of the distorted-wave Born approximation in predicting the magnitude of the cross sections is also different in the two cases.

NUCLEAR REACTIONS ${}^{40}{Ca}$ ( ${}^{11}B$ , ${}^{12}C$ ), $E = 32 and 68$ MeV; ${}^{40}{Ca}$ ( ${}^{13}C$ , ${}^{14}N$ ), $E = 40 and 68$ MeV; DWBA analysis of reactions; optical potential derived for elastic scattering.

Nonstatistical effects in the ${}^{12}C ({}^{15}N, α)$ reaction

M. E. Ortiz, E. Andrade, M. Cardenas, A. Dacal, A. Menchaca-Rocha, J. L. C. Ford, Jr., J. Gomez del Campo, R. L. Robinson, D. Shapira, and E. Aguilera

Phys. Rev. C 22, 1104 (1980) - Published 1 September, 1980

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States in ${}^{23}{Na}$ were populated using the ${}^{12}C ({}^{15}N, α)$ reaction. Excitation functions were measured in the energy range $E_{c . m .} = 9.51 - 17.33$ MeV for 41 states in ${}^{23}{Na}$ from 0 to 12.2 MeV in excitation energy. Angular distributions were measured at selected energies between about 2° and 110° (c.m.). A large number of correlated resonantlike structures with ∼400 keV (c.m.) widths were observed in addition to statistical fluctuations in the ${}^{12}C ({}^{15}N, α)$ data. Forward peaking of the on-resonant angular distributions appear to be a signature of the excitation of high-spin states in the compound nucleus. Elastic scattering excitation functions measured at backward angles show structures which are not well correlated with the anomalies seen in the reaction channels. The ${}^{12}C ({}^{15}N, α)$ data suggest that the resonant portion of the cross sections can be attributed to the population of high-spin levels close to the yrast line of the compound nucleus.

NUCLEAR REACTIONS ${}^{12}C ({}^{15}N, α)$ , $E_{{}^{15}N} = 21.4 to 39.0$ MeV, measured $σ (E)$ for $θ_{lab} = 7 °$ ; measured $σ (θ)$ for $2 <~ θ <~ 110 °$ (c.m.) for selected energies; elastic scattering, $E_{{}^{15}N} = 22 to 31.8$ MeV, measured $σ (E)$ at 160.2°, 161.4°, 162.6°, 163.8°, and 165° (c.m.); measured $σ (θ)$ for $142 <~ θ <~ 170 °$ (c.m.) for selected energies, fluctuation, Hauser-Feshbach and single-level analyses.

Non-yrast states in ${}^{101}{Pd}$ and their rotational interpretation

Rakesh Popli, F. A. Rickey, and P. C. Simms

Phys. Rev. C 22, 1121 (1980) - Published 1 September, 1980

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Several non-yrast states of both parities in ${}^{101}{Pd}$ have been observed using three-detector $γ - γ$ coincidence measurements following the reaction ${}^{92}{Zr} ({}^{12}C, 3 n) {}^{101}{Pd}$ . Energy levels, $γ$ -ray mixing ratios, and branching ratios are deduced from the data and compared with the results of a rotational model calculation. Five of the newly discovered states are identified as non-yrast members of rotational bands based on the $\frac{5}{2^{+}}$ and $\frac{11}{2^{-}}$ states.

NUCLEAR STRUCTURE ${}^{92}{Zr} ({}^{12}C, 3 n) {}^{101}{Pd}$ at 48 MeV; measured $I_{γ} (θ)$ , 3-detector $γ - γ$ coin, $γ - γ$ DCOQ. ${}^{101}{Pd}$ deduced levels, $J$ , $π$ , $γ$ mixing ratios. Rotational model calculations, Coriolis, recoil, calculated levels, mixing ratios, branching ratios, half-lives.

High-spin states and band structure in ${}^{76}{Se}$

J. C. Wells, Jr., R. L. Robinson, H. J. Kim, R. O. Sayer, R. B. Piercey, A. V. Ramayya, J. H. Hamilton, and C. F. Maguire

Phys. Rev. C 22, 1126 (1980) - Published 1 September, 1980

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High-spin states of ${}^{76}{Se}$ have been investigated through observations of $γ$ rays produced in the ${}^{71}{Ga} ({}^{7}{Li}, 2 n)$ reaction by bombarding an enriched ${}^{71}{Ga}$ target with 15- to 22-MeV ${}^{7}{Li}$ ions. Measurements were made of $γ$ -ray singles and $γ - γ$ coincidence spectra, excitation functions, $γ$ -ray angular distributions, $γ - γ$ angular correlations, and Doppler broadening of photopeaks. Level energies, decay modes, spins and parities, $γ$ -ray branching ratios, $γ$ -ray radiative admixtures, and lifetimes were deduced. There is evidence for a strongly excited quasirotational band with the highest member observed being a $12^{+}$ state at 5432 keV, for an odd-parity band built on a $5^{-}$ state, and for a $Δ J = 1$ band which has the characteristics of a $γ$ -vibrational band in a deformed nucleus. Interacting boson approximation model calculations are compared with the experimental results.

NUCLEAR REACTIONS ${}^{71}{Ga} ({}^{7}{Li}, 2 n)$ $E = 15 - 22$ MeV; measured $E_{γ}$ , $I_{γ}$ , $γ (θ)$ , $γ γ (θ)$ , $Δ E_{γ} (τ)$ ; ${}^{76}{Se}$ deduced levels, $J$ , $π$ , $δ$ , $τ$ , $γ$ branching.

Gamow-Teller sum rules and the ${}^{14}C$ ( ${}^{6}{Li}$ , ${}^{6}{He}$ ) ${}^{14}N$ reaction

W. R. Wharton, C. D. Goodman, and D. C. Hensley

Phys. Rev. C 22, 1138 (1980) - Published 1 September, 1980

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A correlation between the ( ${}^{6}{Li}$ , ${}^{6}{He}$ ) cross sections and the Gamow-Teller strength observed previously for other targets persists in the ${}^{14}C$ ( ${}^{6}{Li}$ , ${}^{6}{He}$ ) ${}^{14}N$ reaction. The total Gamow-Teller strength up to 12 MeV excitation is measured and we derive sum rules for the Gamow-Teller strength which depend on the $LS$ configurations of the target state. The extracted $LS$ configuration of the ${}^{14}C$ ground state is in serious disagreement with shell model calculations. There are several inconsistencies within our understanding of the nuclear structure and transition strengths in these nuclei, part of which is attributable to mesonic currents. Constraints are also placed upon the ( ${}^{6}{Li}$ , ${}^{6}{He}$ ) reaction mechanism.

NUCLEAR REACTIONS ${}^{14}C$ ( ${}^{6}{Li}$ , ${}^{6}{He}$ ) ${}^{14}N$ , $E = 62$ MeV; measured $σ (θ)$ . Deduced GT sum rule and ${}^{14}C$ ground state wave function.

Analysis of heavy ion reactions using projection operators

Thomas L. Larry and William P. Beres

Phys. Rev. C 22, 1145 (1980) - Published 1 September, 1980

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A projection operator method based on the Feshbach doorway approach is developed for low-energy heavy-ion scattering. Applications to ${}^{12}C$ + ${}^{12}C$ and ${}^{12}C$ + ${}^{16}O$ are made with doorways taken as quasibound or virtual states of the reduced mass coupled to $2^{+}$ and $3^{-}$ vibrations. For ${}^{12}C$ + ${}^{12}C$ the elastic differential cross section at 90° c.m. is calculated. For ${}^{12}C$ + ${}^{16}O$ we calculate the ratio of the differential cross section to the Rutherford cross section at a range of angles between 90° and 160° c.m. In both cases the calculations agree well with experiment by producing both the gross and intermediate molecular structure. The conditions under which intermediate structure can be expected are discussed.

NUCLEAR REACTIONS ${}^{12}C$ + ${}^{12}C$ elastic scattering, $E = 10 - 30$ MeV c.m., ${}^{12}C$ + ${}^{16}O$ elastic scattering, $E = 18 - 26$ MeV c.m., projection operator intermediate structure theory, calculated $σ (90 °)$ for ${}^{12}C$ + ${}^{12}C$ and $\frac{σ}{σ_{Ruth}}$ (90°-160°, increments of 10°) for ${}^{12}C$ + ${}^{16}O$ .

Shape parametrization for liquid-drop studies

S. Trentalange, S. E. Koonin, and A. J. Sierk

Phys. Rev. C 22, 1159 (1980) - Published 1 September, 1980

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We present a new method for defining axially symmetric shapes which is particularly appropriate for describing elongated and multineck configurations. This shape parametrization is used to describe the static properties of incompressible, charged liquid drops. In particular, we calculate the properties of binary-fission saddle points and compare these with results using other methods. We also present the geometrical properties and normal mode analyses of the two-and three-necked saddle-point families.

NUCLEAR REACTIONS, FISSION Liquid-drop model; new shape parametrization; calculated binary-fission saddle points, multinecked saddle points, normal modes of saddle-point shapes; Werner-Wheeler approximation.

Proton scattering from ${}^{154}{Sm}$ and ${}^{176}{Yb}$ at 0.8 GeV

M. L. Barlett, J. A. McGill, L. Ray, M. M. Barlett, G. W. Hoffmann, N. M. Hintz, G. S. Kyle, M. A. Franey, and G. Blanpied

Phys. Rev. C 22, 1168 (1980) - Published 1 September, 1980

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Elastic and inelastic angular distributions for 0.8 GeV $p$ + ${}^{154}{Sm}$ and ${}^{176}{Yb}$ are reported and analyzed using the distorted-wave Born approximation and the coupled-channels formalism where phenomenological deformed optical potentials are used in the latter analysis. As expected, the multipole moments extracted from the optical potentials are found to be in excellent agreement with those of the charge densities as obtained from electron scattering and Coulomb excitation experiments. The analysis also clearly demonstrates that multistep processes are important at 0.8 GeV and must be included for a proper description of the experimental data.

NUCLEAR REACTIONS ${}^{154}{Sm} (p, p^{'})$ , ${}^{176}{Yb} (p, p^{'})$ , $E = 0.8$ GeV, measured $σ (θ)$ ; enriched targets; resolution ∼50 keV, $θ_{c . m .} = 4.5 ° to 21 °$ , $Δ θ = 0.1 °$ ; optical model potential, DWBA analysis, coupled-channels analysis, rotational model, multipole moments.

Isospin quintets in the $1 p$ and $s - d$ shells

G. R. Burleson, G. S. Blanpied, G. H. Daw, A. J. Viescas, C. L. Morris, H. A. Thiessen, S. J. Greene, W. J. Braithwaite, W. B. Cottingame, D. B. Holtkamp, I. B. Moore, and C. F. Moore

Phys. Rev. C 22, 1180 (1980) - Published 1 September, 1980

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The pion double-charge exchange reaction ( $π^{+}, π^{-}$ ) has been used to measure the ground-state masses of ${}^{12}O$ , ${}^{16}{Ne}$ , ${}^{24}{Si}$ , and ${}^{32}{Ar}$ . The mass excesses were found to be 32.059(48), 24.051(45), 10.682(52), and - 2.181(50) MeV, respectively. These are the first reported measurements of the masses of ${}^{24}{Si}$ and ${}^{32}{Ar}$ and the values for ${}^{12}O$ and ${}^{16}{Ne}$ are improved over previous results. Good agreement with the isobaric multiplet mass equation $M = a + b T_{z} + c {T_{z}}^{2}$ is obtained for the known members of all four quintets.

NUCLEAR REACTIONS Pion double-charge exchange, ${}^{9}{Be} (π^{+}, π^{-}) {}^{9}C$ , ${}^{12}C (π^{+}, π^{-}) {}^{12}O$ , ${}^{13}C (π^{+}, π^{-}) {}^{13}O$ , ${}^{16}O (π^{+}, π^{-}) {}^{16}{Ne}$ , ${}^{24}{Mg} (π^{+}, π^{-}) {}^{24}{Si}$ , ${}^{32}S (π^{+}, π^{-}) {}^{32}{Ar}$ , $E = 180$ MeV, measured $Q$ and $\frac{d σ}{d Ω}$ (5°).

Measurement of cross sections and asymmetry parameters for the production of charged pions from various nuclei by 585-MeV protons

J. F. Crawford, M. Daum, G. H. Eaton, R. Frosch, H. Hirschmann, R. Horisberger, J. W. McCulloch, E. Steiner, R. Hausammann, R. Hess, and D. Werren

Phys. Rev. C 22, 1184 (1980) - Published 1 September, 1980

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We have measured the differential cross section $\frac{d^{2} σ}{d Ω d T_{π}}$ and the polarization parameter $P$ for the production of $π^{+}$ and $π^{-}$ in various target nuclei ( ${}^{1}H$ , ${}^{2}H$ , Be, C, O, Al, Ni, Cu, Mo, and Pb) by protons with a kinetic energy of 585 MeV, for production angles $θ_{π} = 22.5 °, 45 °, 60 °, 90 °, and 135 °$ , and for pion kinetic energies $T_{π}$ of 24, 35, 46, 88, 151, 192, and 254 MeV (all quantities in the laboratory system). Our data disagree strongly with recent data for 580-MeV protons. On the other hand, for pion energies up to 150 MeV, our cross sections differ little from those measured for a proton energy of 730 MeV. For nuclei with $A > 20$ , the total production cross sections $σ (π^{+})$ and $σ (π^{-})$ show the $Z^{\frac{1}{3}}$ and $N^{\frac{2}{3}}$ proportionality expected from theoretical arguments. There is evidence in our data of a shift of the $π^{+}$ energy distributions compared to the $π^{-}$ distributions due to the effects of the Coulomb field of the nuclear protons on the emitted pions.

NUCLEAR REACTIONS ${}^{1}H$ , ${}^{2}H$ , Be, C, O, Al, Ni, Cu, Mo, Pb $p$ , $π^{\pm}$ , $T_{p} = 585$ MeV; measured $σ (T_{π}, θ_{π})$ and asymmetry parameter $P (T_{π}, θ_{π})$ .

Nuclear form factor sensitivity in the reaction ${}^{3}{He} (π^{-}, π^{0}) {}^{3}H$

W. J. Gerace, J. P. Mestre, J. F. Walker, and D. A. Sparrow

Phys. Rev. C 22, 1197 (1980) - Published 1 September, 1980

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Charge exchange angular distributions for the reaction ${}^{3}{He} (π^{-}, π^{0}) {}^{3}H$ are calculated using realistic nuclear form factors obtained from electron scattering experiments in the Glauber multiple scattering formalism. It is found that the charge exchange scattering is not very sensitive to the magnetic form factors at low $q$ and, in particular, is not sensitive to changes in the mean square magnetic radius at the ±5% level. Calculations are also compared with the most recent experimental results.

NUCLEAR REACTIONS ${}^{3}{He} (π^{-}, π^{0}) {}^{3}H$ , nuclear structure form factors, Glauber multiple scattering theory.

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Erratum: Scattering and reaction dynamics for the ${}^{12}C$ + $p$ system

Erratum: Electroexcitation of ${}^{6}{Li}$ with application to the reactions ${}^{6}{Li} {(π^{-}, γ)}_{1 s}$ ${}^{6}{He}$ ( $0^{+}$ , $2^{+}$ )

Pre-equilibrium process for ${}^{175}{Lu} (p, xn γ)$ , ${}^{176}{Yb} ({}^{3}{He}, xn yp γ)$ , and ${}^{174, 176}{Yb} (α, xn γ)$ reactions

Electrodisintegration of ${}^{58}{Ni}$ , ${}^{60}{Ni}$ , and ${}^{62}{Ni}$

Classical-equations-of-motion calculations of high-energy heavy-ion collisions

Nucleus-nucleus total reaction cross sections

Magnetic moments of the $2_{1}^{+}$ levels in ${}^{92}{Zr}$ and ${}^{94}{Zr}$

Application of a band-crossing model for resonances in ${}^{16}O$ + ${}^{16}O$ scattering

Light-charged-particle emission in ${}^{40}{Ar}$ -induced reactions: A probe of the very early evolution of the collisions

Comparison of the single-proton pickup reactions ${}^{40}{Ca}$ ( ${}^{11}B$ , ${}^{12}C$ ) ${}^{39}K$ and ${}^{40}{Ca}$ ( ${}^{13}C$ , ${}^{14}N$ ) ${}^{39}K$ at low and high bombarding energies

Nonstatistical effects in the ${}^{12}C ({}^{15}N, α)$ reaction

Non-yrast states in ${}^{101}{Pd}$ and their rotational interpretation

High-spin states and band structure in ${}^{76}{Se}$

Gamow-Teller sum rules and the ${}^{14}C$ ( ${}^{6}{Li}$ , ${}^{6}{He}$ ) ${}^{14}N$ reaction

Analysis of heavy ion reactions using projection operators

Shape parametrization for liquid-drop studies

Proton scattering from ${}^{154}{Sm}$ and ${}^{176}{Yb}$ at 0.8 GeV

Isospin quintets in the $1 p$ and $s - d$ shells

Measurement of cross sections and asymmetry parameters for the production of charged pions from various nuclei by 585-MeV protons

Nuclear form factor sensitivity in the reaction ${}^{3}{He} (π^{-}, π^{0}) {}^{3}H$

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