Recent Articles

Isoscalar and isovector transition amplitudes in $A = 13$

R. J. Peterson, J. R. Shepard, and R. A. Emigh

Phys. Rev. C 24, 826 (1981) - Published 1 September, 1981

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Data for the isovector charge exchange reaction ( ${}^{3}{He}$ , $t$ ) on ${}^{13}C$ are compared to ${}^{3}{He}$ inelastic scattering data containing both isovector and isoscalar parts, and to strictly isoscalar inelastic ${}^{4}{He}$ scattering to determine the ratio of $Δ T = 1$ to $Δ T = 0$ transition amplitudes for several states. These amplitudes are used to compute the charge asymmetry for $π^{+}$ and $π^{-}$ inelastic scattering on ${}^{13}C$ and good agreement is found for six excited states. A ratio of mirror electromagnetic reduced transition rates is also correctly predicted. Several scattering mechanism models are compared for the excitation of the high-spin $\frac{7}{2^{+}}$ and $\frac{9}{2^{+}}$ states of ${}^{13}C$ or ${}^{13}N$ but no single mechanism can be shown to dominate.

NUCLEAR REACTIONS ${}^{13}C$ ( ${}^{3}{He}$ , ${}^{3}{He}$ ′) ( ${}^{3}{He}$ , $t$ )( ${}^{4}{He}$ , ${}^{4}{He}$ ′) $E_{{}^{3}{He}} = 43.6$ MeV, $E_{α} = 35.5$ MeV; measured $σ (E, θ)$ , deduce ratio of isovector to isoscalar transition amplitude.

Continuous spectra of protons and deuterons from the $α + α$ interaction in the incident energy interval 110-172 MeV

G. Paić, B. Antolković, A. Djaloeis, J. Bojowald, and C. Mayer Böricke

Phys. Rev. C 24, 841 (1981) - Published 1 September, 1981

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The inclusive proton and deuteron spectra from the $α + α$ interaction at $E_{α} = 110, 130, 158, and 172$ MeV measured in the angular range $9 ° \leq θ_{lab} \leq 50 °$ are presented. The shape of the spectra are satisfactorily fitted using the Fermi statistical partition model which yields spectra whose shape are dictated by the phase space allowed to the particles present in the final state. The success of this model points to the importance of that mode of breakup in nuclear reactions below the pion production threshold.

NUCLEAR REACTIONS ${}^{4}{He}$ ( $α$ , $x$ ); $x = p, d$ , $E = 110 - 172$ MeV; measured $σ (E, θ)$ ; statistical partition-model analysis; deduced contribution strength of various breakup modes. Gas target.

Photodisintegration of ${}^{3}H$ and ${}^{3}{He}$

D. D. Faul, B. L. Berman, P. Meyer, and D. L. Olson

Phys. Rev. C 24, 849 (1981) - Published 1 September, 1981

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The photoneutron cross sections for ${}^{3}H$ and ${}^{3}{He}$ have been measured from threshold to ∼25 MeV with monoenergetic photons from the annihilation in flight of fast positrons. These reactions include the two-body breakup of ${}^{3}H$ and the three-body breakup of both ${}^{3}H$ and ${}^{3}{He}$ ; these measurements for ${}^{3}H$ are the first to span the energy region across the peaks of the cross sections. An efficient B $F_{3}$ -tube-and-paraffin neutron detector and high-pressure gaseous samples were employed in these measurements. The results, when compared with each other and with results for the two-body breakup cross section for ${}^{3}{He}$ from the literature, show that: (a) the two-body breakup cross sections for ${}^{3}H$ and ${}^{3}{He}$ have nearly the same shape, but the one for ${}^{3}{He}$ lies lower in magnitude; (b) the three-body breakup cross section for ${}^{3}{He}$ lies higher in magnitude, broader in the peak region, and also rises less sharply from threshold than that for ${}^{3}H$ ; and (c) these differences between the cross sections for the breakup modes largely compensate in their sum, so that the total photon absorption cross sections for ${}^{3}H$ and ${}^{3}{He}$ are nearly the same in both size and shape at energies near and above their peaks. Theoretical results from the literature disagree with the experimental results to a certain extent over the entire photon-energy region for which the photoneutron cross sections were measured. Sum rule predictions also fail to reproduce the experimental results. These discrepancies constitute a challenge to the principle of charge symmetry of the nuclear force, but more complete theoretical calculations are needed to ascertain whether these discrepancies can be ascribed entirely to electromagnetic effects.

NUCLEAR REACTIONS ${}^{3}H$ ( $γ$ , $n$ ), ${}^{3}H$ ( $γ$ , $2 n$ ), ${}^{3}{He}$ ( $γ$ , $n$ ); measured $σ (E_{γ})$ , threshold to ∼25 MeV; monoenergetic photons, high-pressure gas samples; two-body breakup, three-body breakup, charge asymmetry.

Nonlocal potentials and inadequacies of the Jost function in the description of nuclear phenomena

B. Mulligan and S. B. Qadri

Phys. Rev. C 24, 874 (1981) - Published 1 September, 1981

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This paper considers the conceptual problem of describing the physics of a many body system in terms of a two body $S$ matrix. Projection of the many body problem onto a two body channel results in a potential which is nonlocal. We demonstrate that for a nonlocal potential the analytic structure of the Jost function differs from that associated with a local potential. Moreover, the Jost function, and thus the $S$ matrix, is shown to be an incomplete description of the information in the two body channel. This is accomplished by considering Fredholm determinants associated with scattering integral equations.

NUCLEAR REACTIONS Scattering by a nonlocal potential, Jost functions, $S$ matrices, and Fredholm determinants and their analytic character in the complex plane.

Giant resonances in ${}^{40}{Ca}$

Y. -W. Lui, J. D. Bronson, C. M. Rozsa, D. H. Youngblood, P. Bogucki, and U. Garg

Phys. Rev. C 24, 884 (1981) - Published 1 September, 1981

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Inelastic scattering of 98.5, 116.8, and 129.4 MeV $α$ particles from ${}^{40}{Ca}$ has been measured. Analyses were performed on the region between 13.2 to 22.5 MeV excitation energy. From the angular distributions, states at 13.9 and 14.6 MeV have been identified as $0^{+}$ and $2^{+}$ , and exhaust 6 and 2.5% of the corresponding energy-weighted sum rule, respectively. Structure at about 15.8 MeV can be tentatively assigned $3^{-}$ . The giant quadrupole resonance at $E_{x} = 17.7 \pm 0.2$ MeV exhausting 48 ± 8% of $E 2$ energy-weighted sum rule dominates the spectra in this energy region. The giant monopole resonance is not observed. The angular distribution of the 10.6 MeV state shows $1^{-}$ characteristics and can be explained as an isoscalar dipole state.

NUCLEAR REACTIONS ${}^{40}{Ca}$ ( $α$ , $α^{'}$ ), $E_{α} = 98.5, 116.8, 129.4$ MeV: measured $E_{x}$ , $σ (θ)$ giant resonances, deduced $L$ , $β$ .

Multipolarities of interband transitions in ${}^{164}{Dy}$ via the ${}^{163}{Dy}$ ( $d$ , $p γ$ ) reaction

G. Ch. Madueme

Phys. Rev. C 24, 894 (1981) - Published 1 September, 1981

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Prompt $γ$ -ray and conversion electron spectra from the ( $d$ , $p$ ) stripping reaction on an enriched ${}^{163}{Dy}$ target have been measured with Ge(Li) detectors and a sweeping-current lens plus Si(Li)-detector spectrometer. Forty-one transitions were identified under 2 MeV excitation in ${}^{164}{Dy}$ with the help of electron binding energy differences. Conversion coefficients were obtained and multipolarities extracted for most of the transitions associated with the $K^{π} = 0_{g}^{+}, 2_{γ}^{+}, 2^{-}, and 4^{-}$ bands. Reduced transition probability ratios are compared with the predictions of the adiabatic coupling scheme. The effective $E 0$ to $E 2$ reduced transition rates in the gamma-to-ground state band ( $Δ I = 0$ ) transitions suggest a very weak $Δ K = 2$ band mixing between the $γ$ band and a possible excited $K = 0^{+}$ band. A mixing parameter $Z_{2} = 0.043 \pm 0.009$ is derived on the basis of the $2^{+}$ and $3_{γ}^{+}$ transition rates with respect to the ground-band states.

NUCLEAR REACTIONS ${}^{163}{Dy}$ ( $d$ , $p γ$ ), $E = 10$ MeV, measured $E_{γ}$ , $I_{γ}$ , $E_{ce}$ , $I_{ce}$ , ICC. ${}^{164}{Dy}$ deduced levels, $J$ , $π$ , multipolarities, $γ$ branchings and $B (λ L)$ . Enriched targets, Ge(Li), Si(Li) detectors.

Proton hole states in neutron rich nuclei near $A = 100$

E. R. Flynn, F. Ajzenberg-Selove, Ronald E. Brown, J. A. Cizewski, and J. W. Sunier

Phys. Rev. C 24, 902 (1981) - Published 1 September, 1981

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A study of proton hole states in neutron rich nuclei near $A = 100$ has been carried out using the ( $\vec{t}$ , $α$ ) reaction. Targets of ${}^{104}{Ru}$ and ${}^{110}{Pd}$ were bombarded with a beam of 17 MeV polarized tritons and the reaction $α$ particles detected in a quadrupole-three-dipole spectrometer. Only the $β$ decays of the residual nuclei, ${}^{103}{Tc}$ and ${}^{109}{Rh}$ , have been previously observed. The results indicate a smooth trend with $Z$ of the proton single particle states observed in this region, except for ${}^{103}{Tc}$ . Examination of this nucleus indicates a strong tendency towards deformation.

NUCLEAR REACTIONS ${}^{104}{Ru}$ , ${}^{110}{Pd}$ ( $\vec{t}$ , $α$ ), $E = 17$ MeV; measured $σ (θ)$ , $A_{y}$ . DWBA analysis. ${}^{103}{Tc}$ , ${}^{109}{Rh}$ mass measurement.

Low energy states in ${}^{180}{Ta}$

T. Cousins, T. J. Kennett, and W. V. Prestwich

Phys. Rev. C 24, 911 (1981) - Published 1 September, 1981

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A study of both the ${}^{180}{Ta}$ ( $n$ , $γ$ ) ${}^{181}{Ta}$ and ${}^{181}{Ta}$ ( $γ$ , $n$ ) ${}^{180}{Ta}$ reaction reveals energy levels in ${}^{180}{Ta}$ at 38, 73, 109, 181, 231, 258, and 309 keV. The 73 keV level is shown to be the long-lived $J = 9$ state occurring in nature. Neutron separation energies of 7579±2 keV and 6063.3±0.5 keV have been determined for the ${}^{180}{Ta}$ - ${}^{181}{Ta}$ and ${}^{181}{Ta}$ - ${}^{182}{Ta}$ pairs, respectively. The $Q$ value for thermal nuetron capture on ${}^{180}{Ta}$ was found to be 7652.3±0.5 keV.

NUCLEAR REACTIONS ${}^{180}{Ta}$ ( $n$ , $γ$ ), thermal, measured $γ$ energies, ${}^{181}{Ta}$ ( $γ$ , $n$ ) ${}^{180}{Ta}$ , $E_{γ} = 7724, 7815$ keV, measured neutron energies, deduces levels.

High-spin states in ${}^{107}{In}$ and ${}^{108}{In}$

E. Andersson, P. Herges, H. V. Klapdor, and I. N. Wischnewski

Phys. Rev. C 24, 917 (1981) - Published 1 September, 1981

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High-spin states in ${}^{107, 108}{In}$ have been investigated using the ${}^{92}{Mo}$ ( ${}^{19}F$ , $2 p x n γ$ ) ${}^{107, 108}{In}$ reaction. In-beam measurements of $γ - γ$ coincidences, $γ$ -ray excitation functions, and $γ$ -ray angular distributions were performed with Ge(Li) detectors, one of which had a NaI Compton suppression shield. Level schemes for ${}^{107}{In}$ and ${}^{108}{In}$ have been constructed up to states with $I^{π} = (\frac{29}{2^{-}}) and (16^{-})$ , respectively.

NUCLEAR REACTIONS ${}^{92}{Mo}$ ( ${}^{19}F$ , $2 p x n γ$ ) ${}^{107, 108}{In}$ , $E = 65 - 105$ MeV; measured $E_{γ}$ , $γ - γ$ coincidences, $γ$ -ray angular distributions. ${}^{107, 108}{In}$ deduced high-spin states. Enriched target. Anti-Compton spectrometer.

Fusion calculations with the Skyrme interactions

S. J. Krieger and M. S. Weiss

Phys. Rev. C 24, 928 (1981) - Published 1 September, 1981

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The effect on nuclear dynamics of using various parametrizations of the Skyrme potential is studied. In particular, fusion cross sections for the light system ${}^{16}O$ + ${}^{24}{Mg}$ are calculated for the interactions Skyrme II, Skyrme III, Skyrme IV, Skyrme V, and Skyrme VI. The interaction Skyrme III is shown to increase significantly the fusion cross section. An angular momentum window for fusion is observed to occur for $E_{c . m .} ≳ 70$ MeV.

NUCLEAR REACTIONS ${}^{16}O$ ( ${}^{24}{Mg}$ , $x$ ) in time-dependent Hartree-Fock approximation. Effect of nuclear interaction on fusion cross section.

Intermediate-structure fusion resonances observed in the radiative capture of ${}^{12}C$ by ${}^{12}C$

A. M. Nathan, A. M. Sandorfi, and T. J. Bowles

Phys. Rev. C 24, 932 (1981) - Published 1 September, 1981

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We have investigated the ${}^{12}C$ ( ${}^{12}C$ , $γ$ ) ${}^{24}{Mg}$ reaction, populating low-lying states of ${}^{24}{Mg}$ , with ${}^{12}C$ + ${}^{12}C$ c.m. energies between 5 and 11 MeV. High energy $γ$ rays were detected in a large volume NaI spectrometer which had sufficient resolution to distinguish clearly the $γ_{0}$ , $γ_{1}$ , and $γ_{2, 3}$ transitions. Several resonances were observed in each of the decay channels. In particular, the $γ_{0}$ excitation function has four narrow resonances at $E_{c . m .} = 5.6, 6.0, 6.8, and 8.0$ MeV, which are unambiguously assigned $J^{π} = 2^{+}$ . The upper three of these resonances are correlated in all three decay channels but are not correlated either with previously identified $2^{+}$ structures in the ${}^{12}C$ + ${}^{12}C$ system or with structure in the distribution of ground-state $E 2$ strength in ${}^{24}{Mg}$ . Furthermore, calculations demonstrate that these resonances have large nonstatistical ${}^{12}C$ - and photon-partial widths. We argue that the data are suggestive of a new and unusual form of intermediate structure, namely highly clustered ${}^{12}C$ + ${}^{12}C$ configurations built on the ground-state band of ${}^{24}{Mg}$ .

NUCLEAR REACTIONS ${}^{12}C$ ( ${}^{12}C$ , $γ$ ) ${}^{24}{Mg}$ , $5 <~ E_{c . m .} <~ 11$ MeV; measured $E γ$ , $\frac{d σ}{d Ω} (45 °, E_{γ_{0}})$ , $\frac{d σ}{d Ω} (45 °, E γ_{1})$ , $\frac{d σ}{d Ω} (45 °, E γ_{2, 3})$ ; deduced $Γ$ , $Γ_{γ} \frac{Γ_{{}^{12}C}}{Γ}$ , and $E_{c . m .}$ for isolated resonances.

Adiabatic description of dissipative processes in heavy-ion reactions and fission. II. Weak versus strong coupling and the role of the collective velocity

M. C. Nemes and Hans A. Weidenmüller

Phys. Rev. C 24, 944 (1981) - Published 1 September, 1981

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We investigate the friction and diffusion coefficients for a collective variable (nuclear shape degree of freedom, treated classically) coupled with other (intrinsic) degrees of freedom. An adiabatic representation for the intrinsic degrees of freedom is used. The results are remarkably different from those given by linear response theory—the lowest order nonvanishing contribution to the friction coefficient is proportional to ${\dot{Q}}^{3}$ . The physical origin of this behavior is discussed as well as the limits of validity of weak and strong coupling regimes, and their applicability to fission and deep inelastic scattering.

NUCLEAR REACTIONS Heavy ions, fission. Friction and diffusion coefficients in an adiabatic representation. Friction coefficient proportional to ${\dot{Q}}^{3}$ .

Magnetic moments of the $2_{1}^{+}$ states of even-even Te isotopes

N. K. B. Shu, R. Levy, N. Tsoupas, A. Lopez-Garcia, W. Andrejtscheff, and N. Benczer-Koller

Phys. Rev. C 24, 954 (1981) - Published 1 September, 1981

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The magnetic moments of the $2_{1}^{+}$ states of ${}^{120 - 130}{Te}$ isotopes have been measured by the thin-foil transient field technique. The resulting magnetic moments are discussed in the light of predictions of the vibrational, the quasiparticle, and the interacting boson approximation models.

NUCLEAR REACTIONS ${}^{120 - 130}{Te}$ ( ${}^{32}S$ , ${}^{32}S$ ′) ${}^{120 - 130}{Te}$ ( $2_{1}^{+}$ ); $E_{S} \sim 80$ MeV; enriched targets; measured $W (θ, B, \infty)$ through polarized iron; deduced $g (2_{1}^{+})$ .

Fragmentation of ${}^{16}O$ and ${}^{18}O$ projectiles

S. L. Tabor, L. C. Dennis, K. W. Kemper, J. D. Fox, K. Abdo, G. Neuschaefer, D. G. Kovar, and H. Ernst

Phys. Rev. C 24, 960 (1981) - Published 1 September, 1981

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The energy spectra of particles lighter than the beam have been measured following the bombardment of ${}^{12}C$ , ${}^{27}{Al}$ , and ${}^{46}{Ti}$ targets with 72 MeV ${}^{16}O$ beams and 72 and 141 MeV ${}^{18}O$ beams. All the spectra exhibit broad continuum peaks centered at approximately the beam velocity. The shapes of these continuum structures are rather well reproduced by a fragmentation model which assumes that the unobserved fragment is transferred to the target and which contains no adjustable parameters. The ${}^{18}O$ fragmentation spectra on the three targets are very similar in shape. The total yield of fragmentation products is about the same for the ${}^{16}O$ and ${}^{18}O$ beams at 72 MeV, although the $Z$ distribution of strength differs. On the other hand, the fragmentation yield of ${}^{18}O$ increases by a factor of 5 when the beam energy is raised from 72 to 141 MeV, but the relative $Z$ distribution of strength remains constant.

NUCLEAR REACTIONS ${}^{12}C$ , ${}^{27}{Al}$ , ${}^{46}{Ti}$ ( ${}^{16}O$ , $X$ ) and ( ${}^{18}O$ , $X$ ), $X = L i, B e, B, C, N$ , $E = 72 and 141$ MeV; measured $\frac{d σ}{d Ω} (E, θ)$ .

Empirical constraints on the ${}^{16}O$ + ${}^{40}{Ca}$ optical potential

S. Krewald, A. Djaloeis, and S. Gopal

Phys. Rev. C 24, 966 (1981) - Published 1 September, 1981

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The angular distribution between $20 ° ≲ θ_{c . m .} ≲ 180 °$ of ${}^{16}O$ + ${}^{40}{Ca}$ elastic scattering at $E_{c . m .} = 35.7$ MeV has been analyzed in terms of the optical model. For both the real and imaginary parts, the standard Woods-Saxon and spline-function parametrizations of the optical potential have been investigated. In the angular region $θ_{c . m .} ≲ 112 °$ , Woods-Saxon—Woods-Saxon potential combinations suffice to describe the data; however, no fit could be obtained either by Woods-Saxon—Woods-Saxon or by Woods-Saxon—Spline-function potentials for the complete angular distribution ( $θ_{c . m .} ≲ 180 °$ ). In contrast, the Spline-function—Woods-Saxon combination reproduces the experimental data well. No further improvement of fit quality is obtained by parametrizing both the real and imaginary parts in terms of spline functions. The best-fit Spline-function—Woods-Saxon potential is found to consist of a real part, having significant wiggles in the interior, coupled to a shallow imaginary part with a depth $W \sim 2$ MeV and a large radius $R_{i} = 1.60 ({A_{P}}^{\frac{1}{3}} + {A_{T}}^{\frac{1}{3}})$ fm.

NUCLEAR REACTIONS ${}^{16}O$ + ${}^{40}{Ca}$ elastic scattering, $E_{c . m .} = 35.7$ MeV; optical model analysis including a "model-independent" potential parametrization by spline functions.

Production of pions and light fragments at large angles in high-energy nuclear collisions

S. Nagamiya, M. -C. Lemaire, E. Moeller, S. Schnetzer, G. Shapiro, H. Steiner, and I. Tanihata

Phys. Rev. C 24, 971 (1981) - Published 1 September, 1981

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Inclusive cross sections for production of $π^{+}$ , $π^{-}$ , $p$ , $d$ , ${}^{3}H$ , ${}^{3}{He}$ , and ${}^{4}{He}$ have been measured at laboratory angles from 10° to 145° in nuclear collisions of Ne + Naf, Ne + Cu, and Ne + Pb at 400 MeV/nucleon, C + C, C + Pb, Ne + NaF, Ne + Cu, Ne + Pb, Ar + KCl, and Ar + Pb at 800 MeV/nucleon, and Ne + NaF and Ne + Pb at 2.1 GeV/nucleon. The production of light fragments in proton induced collisions at beam energies of 800 MeV and 2.1 GeV has also been measured in order to allow us to compare these processes. For equal-mass nuclear collisions the total integrated yields of nuclear charges are well explained by a simple participant-spectator model. For 800 MeV/nucleon beams the energy spectra of protons at c.m. 90° are characterized by a "shoulder-arm" type of spectrum shape with an exponential falloff at high energies, whereas those of pions are of a simple exponential type. The inverse of the exponential slope, $E_{0}$ , for protons is systematically larger than that for pions. This value of $E_{0}$ is larger for heavier-mass projectiles and targets. It also increases monotonically with the beam energy. The angular anisotropy of protons is larger than that of pions. The yield ratio of $π^{-}$ to total nuclear charge goes up with the beam energy, whereas the yields of composite fragments decrease. The ratio of low-energy $π^{-}$ to $π^{+}$ , as well as that of ${}^{3}H$ to ${}^{3}{He}$ , is larger than the neutron to proton ratio of the system. The spectrum shape of the composite fragments with mass number $A$ is explained very well by the $A th$ power of the observed proton spectra. The sizes of the interaction region are evaluated from the observed coalescence coefficients. The radius obtained is typically 3-4 fm. The yield ratio of composite fragments to protons strongly depends on the projectile and target masses and the beam energy, but not on the emission angle of the fragments. These results are compared with currently available theoretical models.

NUCLEAR REACTIONS Ne + NaF, Ne + Cu, Ne + Pb, $\frac{E}{A} = 400$ MeV/nucleon; C + C, C + Pb, Ne + NaF, Ne + Cu, Ne + Pb, Ar + KCl, Ar + Pb, $\frac{E}{A} = 800$ MeV/nucleon; Ne + NaF, Ne + Pb, $\frac{E}{A} = 2100$ MeV/nucleon; $p$ + C, $p$ + NaF, $p$ + KCl, $p$ + Cu, $p$ + Pb, $E = 800$ MeV; $p$ + C, $p$ + NaF, $p$ + KCl, $p$ + Cu, $p$ + Pb, $E = 2100$ MeV; measured $σ (p, θ)$ for $π^{+}$ , $π^{-}$ , $p$ , $d$ , ${}^{3}H$ , ${}^{3}{He}$ , and ${}^{4}{He}$ .

General properties of energy independent nuclear optical model potentials

S. Y. Lee, F. Osterfeld, K. Tam, and T. T. S. Kuo

Phys. Rev. C 24, 329 (1981) - Published 1 August, 1981

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An energy independent optical potential for nucleon-nucleus scattering is formally derived. A simple relation between energy dependent and energy independent potentials is established showing that the latter has the same thresholds as the former. A generalized dispersion relation for energy independent potentials is found and compared to the conventional dispersion relation of the generalized energy dependent optical potentials.

[REACTION THEORY General formulation of the energy independent optical potential.]

${}^{12}C (p, n) {}^{12}N$ reaction at 120, 160, and 200 MeV

J. Rapaport, T. Taddeucci, C. Gaarde, C. D. Goodman, C. C. Foster, C. A. Goulding, D. Horen, E. Sugarbaker, T. G. Masterson, and D. Lind

Phys. Rev. C 24, 335 (1981) - Published 1 August, 1981

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Angular distributions for the ground-state ( $Δ J^{r} = 1^{+}$ ) and 0.96-MeV ( $Δ J^{π} = 2^{+}$ ) transitions in the ${}^{12}C (p, n) {}^{12}N$ reaction have been measured at incident energies of 120, 160, and 200 MeV. The measured values of the differential cross section align themselves into smooth curves independent of incident energy when converted into plane-wave cross section values and plotted versus momentum transfer. This information supports the hypothesis that the spinisospin term of the effective interaction is almost energy independent in this energy region. Microscopic distortedwave impulse approximation calculations are presented.

[NUCLEAR REACTIONS ${}^{12}C (p, n) {}^{12}N$ , $E = 120, 160, 200$ MeV; measured neutron spectra at several angles between $θ = 0^{\circ}$ and $θ = 30^{\circ}$ ; extracted $σ (E, θ)$ to g.s. and 0.96-MeV states of ${}^{12}N$ . Compared angular distributions with microscopic calculations. Deduced plane-wave cross sections versus momentum transfer.]

Distorted-wave theory for reactions of three charged particles

T. Sauerland

Phys. Rev. C 24, 342 (1981) - Published 1 August, 1981

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For an at least approximate treatment of rearrangement scattering and breakup, a distorted-wave technique is applied to the scattering problem of three charged particles. We give a two-potential formula for the transition operators $U_{ab}$ and obtain generalized Alt-Grassberger-Sandhas integral equations. For the distorted components of the wave function we derive new Faddeev equations with reduced coupling terms. In the case of Coulomb distortion the coupled equations are discussed in detail.

[NUCLEAR REACTIONS Three-body scattering theory, distorted-wave technique, two-potential formula, generalized AGS integral equations, distorted Faddeev equations, approximate treatment of rearrangement scattering and breakup of three charged particles.]

Isospin mixing in the ${}^{2}H (α, α p) n$ reaction

Carl Werntz and F. Cannata

Phys. Rev. C 24, 349 (1981) - Published 1 August, 1981

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We calculate the ${}^{2}H (α, α) {}^{2}H^{*}$ isospin forbidden transition in a nucleon-alpha impulse approximation which includes higher order terms. The results agree qualitatively with the interpretations of experiments which favor a departure from isospin conservation of a few percent at $E_{α} ≃ 24$ MeV and of the order of 30% at $E_{α} ≃ 13$ MeV. The interplay of Coulomb and spin-orbit effects causing the transition to the singlet deuteron is elucidated and the energy and angular dependence of the $d^{*}$ production is presented. A comparison is made with the intermediate coupling shell model of ${}^{6}{Li}$ and isospin mixing in the $2^{+}$ (4.31, $T = 0$ ) and $2^{+}$ (5.36, $T = 1$ ) states is calculated to be of the order of 0.5%. This suggests that the production of the $d^{*}$ occurs through a direct reaction.

[NUCLEAR REACTIONS Deuteron breakup by alphas, theoretical prediction of singlet deuteron production in ${}^{2}{H (α, α p) n}$ ; isospin violation explained by differences in $n$ alpha and $p$ alpha on shell $T$ matrices.]

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Physical Review C

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Isoscalar and isovector transition amplitudes in $A = 13$

Continuous spectra of protons and deuterons from the $α + α$ interaction in the incident energy interval 110-172 MeV

Photodisintegration of ${}^{3}H$ and ${}^{3}{He}$

Nonlocal potentials and inadequacies of the Jost function in the description of nuclear phenomena

Giant resonances in ${}^{40}{Ca}$

Multipolarities of interband transitions in ${}^{164}{Dy}$ via the ${}^{163}{Dy}$ ( $d$ , $p γ$ ) reaction

Proton hole states in neutron rich nuclei near $A = 100$

Low energy states in ${}^{180}{Ta}$

High-spin states in ${}^{107}{In}$ and ${}^{108}{In}$

Fusion calculations with the Skyrme interactions

Intermediate-structure fusion resonances observed in the radiative capture of ${}^{12}C$ by ${}^{12}C$

Adiabatic description of dissipative processes in heavy-ion reactions and fission. II. Weak versus strong coupling and the role of the collective velocity

Magnetic moments of the $2_{1}^{+}$ states of even-even Te isotopes

Fragmentation of ${}^{16}O$ and ${}^{18}O$ projectiles

Empirical constraints on the ${}^{16}O$ + ${}^{40}{Ca}$ optical potential

Production of pions and light fragments at large angles in high-energy nuclear collisions

General properties of energy independent nuclear optical model potentials

${}^{12}C (p, n) {}^{12}N$ reaction at 120, 160, and 200 MeV

Distorted-wave theory for reactions of three charged particles

Isospin mixing in the ${}^{2}H (α, α p) n$ reaction

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