Recent Articles

Inelastic electron scattering from ${}^{18}O$

B. E. Norum, M. V. Hynes, H. Miska, W. Bertozzi, J. Kelly, S. Kowalski, F. N. Rad, C. P. Sargent, T. Sasanuma, W. Turchinetz, and B. L. Berman

Phys. Rev. C 25, 1778 (1982) - Published 1 April, 1982

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Inelastic electron scattering from the low-lying even-parity states of ${}^{18}O$ has been performed. The measurements span a range in momentum transfer from 0.6 to 2.7 ${fm}^{- 1}$ . Form factors have been determined for the two lowest $0^{+}$ excitations, the three lowest $2^{+}$ excitations, and the three lowest $4^{+}$ excitations. Transition densities for the $2^{+}$ and $4^{+}$ excitations have been obtained from a Fourier-Bessel analysis of these data. Comparisons were made with the predictions of various theoretical calculations and the agreement was found generally to be poor. A coexistence model was used to decompose the measured form factors into their single-particle and collective components, which in turn were compared with their counterparts in ${}^{16}O$ and ${}^{17}O$ . The results indicate that this model provides a useful framework within which to understand the structure of the oxygen isotopes. Transition densities also were obtained within the context of this model.

NUCLEAR REACTIONS ${}^{18}O$ ( $e$ , $e^{'}$ ) low-lying even-parity excited states; measured form factors at 90° and 160°, $0.6 \leq q \leq 2.7$ ${fm}^{- 1}$ ; comparison to shell and coexistence models; transition densities extracted.

$γ (d, n) p$ reaction with polarized and unpolarized gamma rays

Reeta Vyas, Manoj Chopra, and M. L. Rustgi

Phys. Rev. C 25, 1801 (1982) - Published 1 April, 1982

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The asymmetry function for the $γ (d, n) p$ reaction is calculated for the Paris and supersoft core potentials for gamma-ray energies, $E_{γ}$ , extending from 20 to 150 MeV, at center of mass angles 45°, 90°, and 135°. The relative photoneutron yield at $E_{γ} = 20$ MeV is also calculated. In addition, the differential cross section, total cross section, and polarization of the outgoing protons are reported. The Paris potential gives good agreement with the experimental data for the differential and total cross sections. However, the discrepancy at 0° still remains. It is found that the asymmetry function cannot be used to distinguish between the various nucleon-nucleon potentials.

NUCLEAR REACTIONS $γ (d, n) p$ . Calculated asymmetry function; total and differential cross sections.

Neutron resonance parameters of ${}_{30}^{68}{Zn}$ + $n$ and statistical distributions of level spacings and widths

J. B. Garg, V. K. Tikku, J. A. Harvey, J. Halperin, and R. L. Macklin

Phys. Rev. C 25, 1808 (1982) - Published 1 April, 1982

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Discrete values of the parameters ( $E_{0}$ , $g Γ_{n}$ , $J^{π}$ , $Γ_{γ}$ , etc.) of the resonances in the reaction ${}_{30}^{68}{Zn}$ + $n$ have been determined from total cross section measurements from a few keV to 380 keV with a nominal resolution of 0.07 ns/m for the highest energy and from capture cross section measurements up to 130 keV using the pulsed neutron time-of-flight technique with a neutron burst width of 5 ns. The cross section data were analyzed to determine the parameters of the resonances using $R$ -matrix multilevel codes. These results have provided values of average quantities as follows: $S_{0} = (2.01 \pm 0.34)$ , $S_{1} = (0.56 \pm 0.05)$ , $S_{2} = (0.2 \pm 0.1)$ in units of $10^{- 4}$ , $D_{0} = (5.56 \pm 0.43)$ keV and $D_{1} = (1.63 \pm 0.14)$ keV. From these measurements we have also determined the following average radiation widths: ${({\bar{Γ}}_{γ})}_{l = 0} = (302 \pm 60)$ meV and ${({\bar{Γ}}_{γ})}_{l = 1} = (157 \pm 7)$ meV. The investigation of the statistical properties of neutron reduced widths and level spacings showed excellent agreement of the data with the Porter-Thomas distribution for $s$ - and $p$ -wave neutron widths and with the Dyson-Mehta $Δ_{3}$ statistic and the Wigner distribution for the $s$ -wave level spacing distribution. In addition, a correlation coefficient of $ρ = 0.50 \pm 0.10$ between $Γ_{n}^{0}$ and $Γ_{γ}$ has been observed for $s$ -wave resonances. The value of $〈 σ_{n γ} 〉$ at (30±10) keV is 19.2 mb.

NUCLEAR REACTIONS ${}_{30}^{68}{Zn}$ ( $n$ , $n$ ), ${}_{30}^{68}{Zn}$ ( $n$ , $γ$ ), $E = few keV to 380, 130 keV$ , respectively. Measured total and capture cross sections versus neutron energy, deduced resonance parameters, $E_{0}$ , $J^{π}$ , $g Γ_{n}$ , $Γ_{γ}$ , $S_{0}$ , $S_{1}$ , $S_{2}$ , $D_{0}$ , $D_{1}$ .

Strong $E 2$ and $M 1$ transitions in ${}^{40}{Ca}$

R. Moreh, W. M. Sandefur, W. C. Sellyey, D. C. Sutton, and R. Vodhanel

Phys. Rev. C 25, 1824 (1982) - Published 1 April, 1982

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Resonance fluorescence is used for measuring the widths of 13 levels in ${}^{40}{Ca}$ below 10.4 MeV among which nine $E 2$ transitions were identified. The total $E 2$ strength of those nine levels together with some other known $2^{+}$ levels below 10 MeV exhausts ∼22% of the energy weighted sum rule. The partial and total widths of the strong $M 1$ state at 10.32 MeV are compared with theory.

NUCLEAR REACTIONS ${}^{40}{Ca}$ ( $γ$ , $γ^{'}$ ), $E = 8.5, 11.3, 11.7$ MeV bremsstrahlung. Deduced $Γ_{0}$ , $Γ (E 2)$ , $Γ (M 1)$ . Natural target.

Neutron deficient platinum and osmium isotopes produced in the ${}^{32}S$ + ${}^{144}{Sm}$ fusion reaction

H. A. Enge, M. Salomaa, A. Sperduto, J. Ball, W. Schier, Arnfinn Graue, and Arne Graue

Phys. Rev. C 25, 1830 (1982) - Published 1 April, 1982

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A recoil-mass selector has been used to detect evaporation residues formed by neutron emission from the compound nucleus ${}^{176}{Pt}$ produced by bombarding ${}^{144}{Sm}$ with 139.5- to 201-MeV ${}^{32}S$ . The neutron-deficient platinum isotopes ${}^{172}{Pt}$ ( $4 n$ emission) and ${}^{171}{Pt}$ ( $5 n$ emission) were identified, among others, as well as their alpha daughters, ${}^{168}{Os}$ and ${}^{167}{Os}$ . The alpha-decay energies and half-lives are ${}^{172}{Pt}$ : 6.09 MeV, 0.09 sec; ${}^{171}{Pt}$ : 6.450 MeV, 0.02 sec, ${}^{168}{Os}$ : 5.670 MeV, 2.2 sec; and ${}^{167}{Os}$ : 5.843 MeV, 0.8 sec. Alpha branching ratios of these and other daughters were also measured. An alpha line at 6.547, observed at beam energies above 190 MeV, was tentatively assigned to ${}^{170}{Pt}$ ( $6 n$ emission) and at energies around 140 MeV indications of $1 n$ emission were observed. The optimum cross sections for $1 n$ , $2 n$ , $3 n$ , $4 n$ , $5 n$ , and $6 n$ emissions in that order are approximately 0.003, 0.09, 1.5, 0.15, 0.02, and 0.002 millibarns. Formation of iridium isotopes by $2 n$ $1 p$ evaporation, etc., was also observed, but is not discussed in detail in this paper.

NUCLEAR REACTIONS, RADIOACTIVITY Complete fusion, ${}^{32}S$ + ${}^{144}{Sm}$ , $E = 139.5 to 201$ MeV laboratory, measured $σ (E)$ , $E_{α}$ , and $t_{\frac{1}{2}}$ for evaporation residues.

Statistical behavior of nucleon transfer to highly excited states in heavy-ion collisions

J. S. Karp, S. G. Steadman, S. B. Gazes, R. Ledoux, and F. Videbæk

Phys. Rev. C 25, 1838 (1982) - Published 1 April, 1982

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The $Q$ -value dependence of the cross section of heavy-ion transfer reactions to high-lying states is studied. The continuum energy spectra are measured for each exit channel while systematically varying the bombarding energy, scattering angle, target and projectile: ${}^{16}O$ + ${}^{232}{Th}$ , ${}^{15}N$ + ${}^{232}{Th}$ and ${}^{181}{Ta}$ , and ${}^{35}{Cl}$ + ${}^{181}{Ta}$ at energies ranging up to 1.4 times the Coulomb barrier, at and about the grazing angle. The transfer reactions exhibit common properties which depend mainly on the number of transferred nucleons $Δ N$ . The average amount of energy dissipated, which depends strongly on $Δ N$ , is interpreted with a semiclassical model that assumes momentum matching and the presence of a velocity-dependent frictional force. Also, the branching ratios of the exit channels are observed to depend systematically on $Δ N$ , which suggests a statistical process. The energy spectra are examined in terms of a phenomenological constrained phase-space analysis. The dominant constraint is found to be the optimal $Q$ value. The description of data with at most two constraints implies that essentially all of the information content of the energy distribution is contained in these constraints.

NUCLEAR REACTIONS Heavy ions, ${}^{232}{Th}$ ( ${}^{16}O$ , $X$ ), $X = {}^{9, 10}{Be}, {}^{11 - 13}B, {}^{12 - 16}C, {}^{15 - 17}N, {}^{17 - 19}O$ , $E = 97, 105, 115, 125$ MeV. ${}^{181}{Ta}$ , ${}^{232}{Th}$ ( ${}^{15}N$ , $X$ ), $X = {}^{9 - 11}{Be}, {}^{11 - 13}B, {}^{12 - 15}C$ , $E = 86, 95, 103$ MeV. ${}^{181}{Ta}$ ( ${}^{35}{Cl}$ , $X$ ), $X = {}^{30 - 32}{Si}, {}^{31 - 34}P, {}^{33 - 36}S, {}^{36, 37}{Cl}$ , $E = 205$ MeV. Energy and angular distributions of the ejectiles. Statistical aspects. Surprisal analysis.

Structure of multiphonon vibrational states in ${}^{108, 110}{Pd}$

I. Y. Lee, N. R. Johnson, F. K. McGowan, R. L. Robinson, M. W. Guidry, L. L. Riedinger, and S. W. Yates

Phys. Rev. C 25, 1865 (1982) - Published 1 April, 1982

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Coulomb excitation of ${}^{108, 110}{Pd}$ has been carried out with ${}^{40}{Ar}$ projectiles. Both three-and four-phonon vibrational states were populated by the multiple excitation process. The level energies of these states and the $B (E 2)$ values deviate significantly from the pure vibrational model. The boson expansion model and the interacting boson model were reasonably successful in describing the gross features of these two nuclei, but failed in some details.

NUCLEAR REACTIONS ${}^{108, 110}{Pd}$ ( ${}^{40}{Ar}$ , ${}^{40}{Ar}$ ') $E = 120 and 129.1$ MeV; measured $γ$ -ray yields at 0° and 55°; coupled-channel Coulomb excitation calculations performed; compared results with model calculations.

Jets of nuclear matter from high energy heavy ion collisions

H. Stöcker, L. P. Csernai, G. Graebner, G. Buchwald, H. Kruse, R. Y. Cusson, J. A. Maruhn, and W. Greiner

Phys. Rev. C 25, 1873 (1982) - Published 1 April, 1982

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The fluid dynamical model is used to study the reactions ${}^{20}{Ne}$ + ${}^{238}U$ and ${}^{40}{Ar}$ + ${}^{40}{Ca}$ at $E_{lab} = 390$ MeV/nucleon. The calculated double differential cross sections $d^{2} \frac{σ}{d Ω} dE$ exhibit sidewards maxima in agreement with recent experimental data. The azimuthal dependence of the triple differential distributions, to be obtained from an event-by-event analysis of $4 π$ exclusive experiments, can yield deeper insight into the collision process: Jets of nuclear matter are predicted with a strongly impact-parameter-dependent thrust angle $θ_{jet} (b)$ .

NUCLEAR REACTIONS Ar+Ca, Ne+U, $E_{lab} = 393$ MeV/nucleon, fluid dynamics with thermal breakup, double differential cross sections, azimuthal dependence of triple differential cross sections, event-by-event thrust analysis of $4 π$ exclusive experiments.

Fusion and compound nuclei decay for light and intermediate-mass systems: ${}^{24}{Mg}$ , ${}^{28}{Si}$ + ${}^{12}C$ , ${}^{24}{Mg}$ + ${}^{24, 26}{Mg}$ , ${}^{28}{Si}$ + ${}^{24}{Mg}$ , ${}^{28, 29, 30}{Si}$

S. Gary and C. Volant

Phys. Rev. C 25, 1877 (1982) - Published 1 April, 1982

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Complete fusion or residue distributions have been measured with several experimental techniques for the following systems: ${}^{24}{Mg}$ , ${}^{28}{Si}$ + ${}^{12}C$ , ${}^{24}{Mg}$ + ${}^{24, 26}{Mg}$ , ${}^{28}{Si}$ + ${}^{24}{Mg}$ , ${}^{28, 29, 30}{Si}$ . The range of energies spreads from 1 to 3 times the Coulomb barrier. None of these systems presents structures in its fusion excitation function as pronounced as the ones observed for lighter entrance channels. The intensities of the residue distribution are generally in agreement with the predictions of a multiple deexcitation code. The shape and absolute values of complete fusion excitation functions are compared to macroscopic models and to the predictions of a coupled-channels approach of the reaction, which gives a more satisfactory account of experimental data.

NUCLEAR REACTIONS Fusion, measured $σ_{fusion} (E, θ)$ , $σ_{residue} (E, θ)$ ; ${}^{24}{Mg}$ + ${}^{12}C$ , $16.4 < E_{c . m .} < 29.8$ MeV; ${}^{28}{Si}$ + ${}^{12}C$ , $15.1 < E_{c . m .} < 24.6$ MeV; ${}^{24}{Mg}$ + ${}^{24}{Mg}$ , $21 < E_{c . m .} < 41.6$ MeV; ${}^{24}{Mg}$ + ${}^{26}{Mg}$ , $20.3 < E_{c . m .} < 32.9$ MeV; ${}^{28}{Si}$ + ${}^{24}{Mg}$ , $24.2 < E_{c . m .} < 38.1$ MeV; ${}^{28}{Si}$ + ${}^{28}{Si}$ , $27.9 < E_{c . m .} < 41.4$ MeV; ${}^{28}{Si}$ + ${}^{29}{Si}$ , $27.4 < E_{c . m .} < 42.1$ MeV; ${}^{28}{Si}$ + ${}^{30}{Si}$ , $27.3 < E_{c . m .} < 42.8$ MeV; comparison with evaporation calculation; barrier parameters deduced from $σ_{CF} (E)$ . Comparison of $σ_{CF} (E)$ with macroscopic models; coupled-channels approach of the fusion strength.

Back-angle scattering of ${}^{12}C$ on ${}^{28}{Si}$

M. S. Hussein and M. P. Pato

Phys. Rev. C 25, 1896 (1982) - Published 1 April, 1982

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A simple model is constructed for the ${}^{12}C$ + ${}^{28}{Si}$ elastic angular distribution and excitation function at back angles. A "structure" concentrated at a critical value of angular momentum smaller than the grazing value in $l$ space is suggested as a viable mechanism. Possible connection to $α$ -particle transfer contribution is pointed out. A short comparison with other models is made.

NUCLEAR REACTIONS Back angle and 90° scattering of ${}^{28}{Si}$ + ${}^{12}C$ is discussed.

Molecular single-particle excitations in heavy-ion reactions involving deformed light nuclei

Jae Young Park, Werner Scheid, and Walter Greiner

Phys. Rev. C 25, 1902 (1982) - Published 1 April, 1982

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Two-center level diagrams for the neutron orbitals in the scattering of ${}^{16}O$ on ${}^{25}{Mg}$ and of ${}^{17}O$ on ${}^{24}{Mg}$ are calculated by using a deformed potential for ${}^{24, 25}{Mg}$ . Possible consequences of the nuclear Landau-Zener mechanism, namely the promotion of nucleons at avoided level crossings, and of the rotational coupling between crossing molecular single-particle orbitals are studied for inelastic excitation and neutron transfer. The important excitation and transfer processes, which are enhanced by the promotion process and the rotational coupling, are presented.

NUCLEAR REACTIONS Heavy ion scattering, theory of nucleon transfer, molecular wave functions, asymmetric two center shell model, single particle excitation, deformed nuclei.

Inelastic scattering of ${}^{16}O$ from ${}^{40, 42, 44, 48}{Ca}$

K. E. Rehm, W. Henning, J. R. Erskine, D. G. Kovar, M. H. Macfarlane, S. C. Pieper, and M. Rhoades-Brown

Phys. Rev. C 25, 1915 (1982) - Published 1 April, 1982

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The inelastic scattering of ${}^{16}O$ has been studied on targets of ${}^{40, 42, 44}{Ca}$ at 60 MeV, and ${}^{48}{Ca}$ at 56 MeV incident energy. Oxygen-16 ions emerging from the reactions were momentum analyzed in a split-pole magnetic spectrograph and identified in the focal plane by a position-sensitive ionization chamber. Angular distributions were extracted for transitions of multipolarity $L = 0 - 5$ to final states with excitation energies below 5 MeV. In most cases single-channel distorted-wave Born approximation calculations fail to reproduce the data, the discrepancies tending to increase with higher multipolarity. Coupled-channels calculations that explicitly treat the strong couplings connecting all final states observed show improved, though not fully satisfactory, agreement with the data.

NUCLEAR REACTIONS ${}^{16}O$ + ${}^{40, 42, 44}{Ca}$ , $E_{lab} = 60$ MeV; ${}^{16}O$ + ${}^{48}{Ca}$ , $E_{lab} = 56$ MeV; elastic and inelastic scattering; measured $σ (θ)$ ; DWBA and coupled channels calculations.

Cluster representation of ${}^{6}{Li}$ and the finite-range distorted-wave Born approximation analysis of ${}^{6}{Li}$ -induced alpha transfer reactions

D. R. Chakrabarty and M. A. Eswaran

Phys. Rev. C 25, 1933 (1982) - Published 1 April, 1982

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With a view to examine the suitability of the various different forms of $α - d$ cluster representation of ${}^{6}{Li}$ used in the literature based on different criteria for the $α$ -transfer reaction analysis, finite-range distorted-wave Born approximation calculations have been made in the present work for ( ${}^{6}{Li}$ , $d$ ) reactions with various forms of cluster representation of ${}^{6}{Li}$ and they are compared with the angular distribution data on the targets ${}^{26}{Mg}$ , ${}^{27}{Al}$ , ${}^{29}{Si}$ , and ${}^{31}P$ at a bombarding energy of 36 MeV. It is found that (a) the single node wave function $ψ_{α d}$ introduced by Kubo and Hirata with the corresponding Woods-Saxon form of $V_{α d}$ is not found to fit the angular distribution data at all, (b) the zero node Eckart function form of $ψ_{α d}$ with the corresponding $V_{α d}$ with attractive and repulsive parts is also not successful, and (c) the zero node wave function generated by a Woods-Saxon form of a potential with a hard repulsive core of $R_{core} = 1.25$ fm introduced by Watson et al. is also unsatisfactory. However, the Watson form modified by reducing the hard core radius to $R_{core} = 0.6$ fm predicts angular distributions satisfactorily. These results are not affected by the different choices of optical model parameters.

NUCLEAR REACTIONS ( ${}^{6}{Li}$ , $d$ ), FRDWBA calculations with different $α - d$ cluster representations of ${}^{6}{Li}$ . Compared $σ (θ)$ data.

Collective band structure to high spin and shape coexistence in ${}^{76}{Kr}$

R. B. Piercey, A. V. Ramayya, J. H. Hamilton, X. J. Sun, Z. Z. Zhao, R. L. Robinson, H. J. Kim, and John C. Wells

Phys. Rev. C 25, 1941 (1982) - Published 1 April, 1982

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Excited states in ${}^{76}{Kr}$ have been investigated via the ${}^{66}{Zn}$ ( ${}^{12}C$ , $2 n$ ) reaction at a beam energy of 39 MeV. Gamma-ray energies, intensities, spins, parities, and mean lives of excited states were extracted from measurements of the $γ$ rays which were emitted in-beam. The energies of 25 excited levels were deduced from $γ - γ$ coincidence data, and all but three of these levels are members of bandlike structures which persist to high spin. The Doppler shift attenuation method was used to extract the lifetimes of thirteen excited levels. The $E 2$ strengths are highly collective. The positive parity yrast band to spin ( $12^{+}$ ) has been observed with a forward bend at low spin, but with no backbending in the moment of inertia below $12^{+}$ . A positive parity band with even- and odd-spin members to ( $6^{+}$ ) and ( $9^{+}$ ) respectively, has been observed, and is interpreted as a $Δ J = 1$ quasigamma band. Negative-parity bands built on $5^{-}$ and ( $6^{-}$ ) levels have been observed to spins of ( $13^{-}$ ) and ( $12^{-}$ ), respectively. Finally, the first excited $0^{+}$ state and a $2^{+}$ level built on it have been identified and are assigned to a near spherical configuration which coexists with the ground state that has an unusually large deformation.

NUCLEAR REACTIONS ${}^{66}{Zn}$ ( ${}^{12}C$ , $2 n$ ) $E = 39$ MeV; measured $E_{γ}$ , $I_{γ}$ , $γ (θ)$ , DCO, DSAM; deduced ${}^{76}{Kr}$ levels, $J$ , $π$ , $B (E 2)$ , $δ$ , and $γ$ branching.

Spin observables in low energy nucleon-antinucleon scattering

C. B. Dover and J. M. Richard

Phys. Rev. C 25, 1952 (1982) - Published 1 April, 1982

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We discuss the model dependence of the spin parameters for low and medium energy antinucleon-nucleon ( $\bar{N} N$ ) scattering. An $\bar{N} N$ potential model is used, consisting of a $t$ -channel meson exchange part, supplemented by a complex annihilation potential, adjusted to reproduce the observed energy dependence of total elastic, inelastic, and charge exchange cross sections. A number of striking spin effects are predicted, particularly in the charge exchange channel. We explore the sensitivity of the effects to changes in the real and imaginary parts of the $\bar{N} N$ potential; in particular, we assess the possibility of extracting the strength of the coherent $\bar{N} N$ tensor potential due to $π$ , $ρ$ , and $ω$ exchange from future data. Some implications of our results for future experiments are mentioned.

NUCLEAR REACTIONS Nucleon-antinucleon scattering, spin-dependent observables.

Influence of the functional form of the density on hadron-nucleus scattering

H. E. Haber and D. A. Sparrow

Phys. Rev. C 25, 1959 (1982) - Published 1 April, 1982

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The results of the analytic approach to hadron scattering of Amado, Dedonder, and Lenz are generalized to include other often used nuclear density parametrizations. The necessary integrals involving the nuclear density and their radial moments are evaluated in closed form for several commonly used parametrizations. These results, when combined with asymptotic analytic expressions for hadron-nucleus scattering, provide insights into the dependence of elastic and inelastic hadron scattering on the functional form of the nuclear density. Our results demonstrate the empirical mixing of interaction strengths and target densities and establish the independence of high- $q$ hadronic and low- $q$ electromagnetic measures of coupling strengths.

NUCLEAR REACTIONS Analytic forms for nuclear amplitudes; dependence of the scattering on nuclear densities; inelastic coupling strengths.

Spin transfer measurements for $pp \to pp$ at 800 MeV

M. W. McNaughton, B. E. Bonner, W. D. Cornelius, E. W. Hoffman, O. B. van Dyck, R. L. York, R. D. Ransome, C. L. Hollas, P. J. Riley, and K. Toshioka

Phys. Rev. C 25, 1967 (1982) - Published 1 April, 1982

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The spin depolarization parameters $D_{NN}$ , $D_{SS}$ , $D_{LS}$ , and the spin transfer parameters $K_{NN}$ , $K_{SS}$ , $K_{LS}$ have been measured for $pp \to pp$ at 800 MeV. Angular range is 21 to 90° c.m. for the $D$ parameters, and 46 to 90° c.m. for the $K$ parameters. Typical uncertainties are about ±0.025. These data, when combined with previous data make possible a complete isovector phase shift and amplitude analysis at 800 MeV.

NUCLEAR REACTIONS ${}^{1}H$ ( $p$ , $p$ ) ${}^{1}H$ , $E = 800$ MeV, measured $D_{NN}$ , $D_{SS}$ , $D_{LS}$ , $K_{NN}$ , $K_{SS}$ , $K_{LS}$ , $θ = 21 to 90 °$ c.m.

Lee model and three-particle equations

Michael G. Fuda

Phys. Rev. C 25, 1972 (1982) - Published 1 April, 1982

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It is shown that the amplitudes for the processes $V + θ \to V + θ$ , $V + θ \to N + 2 θ$ , and $N + 2 θ \to N + 2 θ$ in the Lee model can be obtained from the solution of an Amado-Lovelace type of three-particle equation. Furthermore, the solution of this three-particle equation can be obtained in closed form.

NUCLEAR REACTIONS Amado-Lovelace equations for $V - θ$ sector of Lee model.

$NN$ single pion production cross sections below 1500 MeV

B. J. VerWest and R. A. Arndt

Phys. Rev. C 25, 1979 (1982) - Published 1 April, 1982

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The isospin reaction cross sections for $NN$ single pion production are extracted from data for the processes $NN \to π d$ and $NN \to NN π$ . New data in conjunction with older existing data have precisely determined the components of the cross sections for the isospin one ( $pp$ ) initial state. Other new data for the $np$ initial state and correct treatment of some older data indicate that the isospin zero reaction cross section is essentially zero below 1000 MeV, which indicates against the presence of inelastic isospin zero $NN$ resonances.

NUCLEAR REACTIONS Nucleon-nucleon scattering, $π$ production reaction cross sections, isospin decomposition, isospin cross sections deduced from data.

Nuclear form factors in the timelike region and photoproduction of pions in nuclei

B. Bosco, C. W. Kim, and S. L. Mintz

Phys. Rev. C 25, 1986 (1982) - Published 1 April, 1982

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The requirement of gauge invariance is applied to the matrix element for pion photoproduction near threshold for spin $½^{\pm}$ → $½^{\pm}$ and $0^{\pm}$ → $1^{\pm}$ transitions and leads to relations between $F_{A} (μ^{2})$ and $F_{A} (- μ^{2})$ , and to partially conserved axial-vector current relations. These relations lead to theoretical predictions for cross sections consistent with experiment within the level of approximations made. Straightforward analytic continuation of the axial-vector form factor to the timelike region is also examined.

NUCLEAR REACTIONS Gauge invariance, PCAC, weak nuclear form factors for ${}^{6}{Li}$ ( $γ$ , $π^{+}$ ) ${}^{6}{He}$ and ${}^{12}C$ ( $γ$ , $π^{+}$ ) ${}^{12}B$ .

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Inelastic electron scattering from ${}^{18}O$

$γ (d, n) p$ reaction with polarized and unpolarized gamma rays

Neutron resonance parameters of ${}_{30}^{68}{Zn}$ + $n$ and statistical distributions of level spacings and widths

Strong $E 2$ and $M 1$ transitions in ${}^{40}{Ca}$

Neutron deficient platinum and osmium isotopes produced in the ${}^{32}S$ + ${}^{144}{Sm}$ fusion reaction

Statistical behavior of nucleon transfer to highly excited states in heavy-ion collisions

Structure of multiphonon vibrational states in ${}^{108, 110}{Pd}$

Jets of nuclear matter from high energy heavy ion collisions

Fusion and compound nuclei decay for light and intermediate-mass systems: ${}^{24}{Mg}$ , ${}^{28}{Si}$ + ${}^{12}C$ , ${}^{24}{Mg}$ + ${}^{24, 26}{Mg}$ , ${}^{28}{Si}$ + ${}^{24}{Mg}$ , ${}^{28, 29, 30}{Si}$

Back-angle scattering of ${}^{12}C$ on ${}^{28}{Si}$

Molecular single-particle excitations in heavy-ion reactions involving deformed light nuclei

Inelastic scattering of ${}^{16}O$ from ${}^{40, 42, 44, 48}{Ca}$

Cluster representation of ${}^{6}{Li}$ and the finite-range distorted-wave Born approximation analysis of ${}^{6}{Li}$ -induced alpha transfer reactions

Collective band structure to high spin and shape coexistence in ${}^{76}{Kr}$

Spin observables in low energy nucleon-antinucleon scattering

Influence of the functional form of the density on hadron-nucleus scattering

Spin transfer measurements for $pp \to pp$ at 800 MeV

Lee model and three-particle equations

$NN$ single pion production cross sections below 1500 MeV

Nuclear form factors in the timelike region and photoproduction of pions in nuclei

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