Recent Articles

Spectroscopy of excited states in ${}^{102}{Mo}$ and ${}^{106}{Ru}$

J. Koenig, H. Bohn, T. Faestermann, P. Kienle, H. J. Körner, W. A. Mayer, D. Pereira, K. E. Rehm, and H. J. Scheerer

Phys. Rev. C 24, 2076 (1981) - Published 1 November, 1981

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Excited states in the transitional nuclei ${}^{102}{Mo}$ and ${}^{106}{Ru}$ have been populated in ${}^{18}O$ induced two neutron transfer reactions at bombarding energies around 5 MeV/nucleon. The succeeding $γ$ decay was measured employing a particle- $γ$ coincidence technique in which the ejectiles were identified with a quadrupole-three-dipole magnetic spectrograph. This method is especially suited for studying the decay modes of regions with selected excitation energy and spin. A characteristic evolution in the population of known states ( $I^{π} \leq 4^{+}$ ) with changing excitation energy was observed. Previously unknown $γ$ transitions are attributed to the decay of $6^{+}$ and $8^{+}$ yrast states in ${}^{102}{Mo}$ and ${}^{106}{Ru}$ , respectively.

NUCLEAR REACTIONS ${}^{100}{Mo}$ ( ${}^{18}O$ , ${}^{16}O$ ), $E_{lab} ({}^{18}O) = 84$ MeV, $θ_{lab} = 34 °$ ; ${}^{104}{Ru}$ ( ${}^{18}O$ , ${}^{16}O$ ), $E_{lab} ({}^{18}O) = 84 and 100$ MeV, $θ_{lab} = 34 ° and 30 °$ . Measured particle- $γ$ coinc. for selected excitation energy ranges, deduced ${}^{102}{Mo}$ and ${}^{106}{Ru}$ level energies (and spins). Enriched targets.

Fast protons and alpha particles from the ${}^{12}C$ + ${}^{60}{Ni}$ reaction

R. L. Robinson, R. L. Auble, I. Y. Lee, M. J. Martin, G. R. Young, J. Gomez del Campo, J. B. Ball, F. E. Bertrand, R. L. Ferguson, C. B. Fulmer, J. R. Wu, J. C. Wells, and H. Yamada

Phys. Rev. C 24, 2084 (1981) - Published 1 November, 1981

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The emission of energetic light ions from heavy-ion induced reactions was studied by measuring coincidences of protons and alpha particles with (1) $Z = 1 to 7$ particles, (2) discrete $γ$ rays, and (3) $γ$ -ray multiplicities from bombardment of ${}^{60}{Ni}$ with ${}^{12}C$ ions. Incident beam energies were 136 and 194 MeV. Discrete $γ$ rays were used to identify the residual targetlike fragments. Most of the particle-particle coincident angular correlations are strongly peaked in the forward direction; the full widths at half maximum of the proton distributions are typically 50°, those of the alpha particles are 30°. The $N - Z$ distributions of the residual nuclei peak around ${}^{60}{Ni}$ . The $γ$ -ray multiplicities are insensitive to the energy of the gating energetic light ion and are about 9 for 136-MeV ${}^{12}C$ projectiles and 10 for 194 MeV. The results indicate the contribution of more than one mechanism in producing the high-energy light ions. In part the energetic light ions are emitted in association with a projectilelike fragment. A major component of the energetic light ions can be explained as emission from the projectilelike fragment during the collision process followed by fusion of the remainder of the fragment with the target.

NUCLEAR REACTIONS ${}^{60}{Ni}$ ( ${}^{12}C$ , $p$ ), ( ${}^{12}C$ , $α$ ) $E = 136, 194$ MeV; measured $σ (E, θ)$ in coincidence with $Z = 1 - 6$ particles, $γ$ rays and $γ$ multiplicities.

Production of the neutron-rich nuclides ${}^{20}C$ and ${}^{27}F$ by fragmentation of 213 MeV/nucleon ${}^{48}{Ca}$

J. D. Stevenson and P. B. Price

Phys. Rev. C 24, 2102 (1981) - Published 1 November, 1981

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Production cross sections of neutron-rich projectile fragments have been measured for the reaction 213 MeV/nucleon ${}^{48}{Ca}$ +Be. The neutron-rich nuclides ${}^{20}C$ and ${}^{27}F$ have been observed for the first time. A method to strengthen our evidence for the possible particle stability of ${}^{21}C$ , ${}^{23}N$ , and ${}^{25}O$ is presented.

RADIOACTIVITY First observation of ${}^{20}C$ and ${}^{27}F$ produced in fragmentation of 213 MeV/nucleon ${}^{48}{Ca}$ .

Gyromagnetic ratios of low-lying excited states in ${}^{196}{Pt}$

A. E. Stuchbery, C. G. Ryan, I. Morrison, and H. H. Bolotin

Phys. Rev. C 24, 2106 (1981) - Published 1 November, 1981

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The gyromagnetic ratios of the $2_{2}^{+}$ and $4_{1}^{+}$ states in ${}^{196}{Pt}$ were measured relative to that of its $2_{1}^{+}$ level. The thin-foil ion-implantation perturbed-angular-correlation technique was employed utilizing the enhanced transient hyperfine magnetic field present at the nuclei of swiftly recoiling ions traversing magnetized ferromagnetic materials. The states of interest were populated by Coulomb excitation using beams of 220-MeV ${}^{58}{Ni}$ ions. For $g (2_{1}^{+})$ taken as 0.326±0.014, the present measurements yielded $g (2_{2}^{+}) = 0.30 \pm 0.06$ and $g (4_{1}^{+}) = 0.30 \pm 0.05$ . These results and those reported by prior workers for the $g$ factors of corresponding states in ${}^{192}{Pt}$ , ${}^{194}{Pt}$ , and ${}^{198}{Pt}$ are used to trace the systematics of the gyromagnetic ratios of these low-lying levels in the even ${}^{192 - 198}{Pt}$ isotopes. These experimental findings are compared in detail with interacting boson approximation model-based predictions.

NUCLEAR REACTIONS ${}^{196}{Pt}$ (Ni,Ni') ${}^{196}{Pt}$ ( $2_{1}^{+}$ , $2_{2}^{+}$ , $4_{1}^{+}$ ), $E = 220$ MeV; measured $γ (θ, H)$ in polarized Fe, particle- $γ$ coin, Coulomb excitation. ${}^{196}{Pt}$ levels deduced $g$ . Enriched target, thin foil technique. NUCLEAR STRUCTURE ${}^{192, 194, 196, 198}{Pt}$ ; calculated $g$ . Interacting boson approximation, near-0(6) limit.

${}^{209}{Bi}$ + ${}^{136}{Xe}$ reaction at $E_{lab} = 1422$ MeV

H. J. Wollersheim, W. W. Wilcke, J. R. Birkelund, J. R. Huizenga, W. U. Schröder, H. Freiesleben, and D. Hilscher

Phys. Rev. C 24, 2114 (1981) - Published 1 November, 1981

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Projectilelike reaction products from the ${}^{209}{Bi}$ + ${}^{136}{Xe}$ reaction were studied at a laboratory bombarding energy of 1422 MeV. The fragments were identified by atomic number, and their kinetic energies and angular distributions were measured using three solid-state $Δ E - E$ telescopes. The strongly damped products exhibit features similar to those seen in two previous measurements of the same reaction at 940 and 1130 MeV. The angular distribution is peaked near the grazing angle. The minimum kinetic energy is bombarding-energy independent and 150 MeV smaller than the Coulomb energy of touching spherical fragments, indicating a large deformation of these dinuclear systems. The measured element distributions for given $Q$ values are found to be Gaussian and centered at the atomic number of the projectile. At large negative $Q$ values, the centroids of the Gaussian distributions exhibit a small drift towards charge splits more asymmetric than the initial system. Various correlations between experimental observables, including the variances of the $Z$ distributions, the centroids of the angular distributions, and the $Q$ values, are interpreted for all three bombarding energies in terms of the proximity one-body transport model. The experimental relations are satisfactorily reproduced by this theory.

NUCLEAR REACTIONS ${}^{209}{({}^{136}{Xe}, H I)}$ ; $E_{lab} = 1422$ MeV; one-particle inclusive measurement of $σ (E, Z, θ)$ ; strongly damped reaction; extracted first and second moments of element distributions and centroids of angular distributions as a function of $Q$ value; comparison with proximity one-body transport model.

${}^{14}C$ ( ${}^{6}{Li}$ , $t$ ) ${}^{17}O$ reaction at $E ({}^{6}{Li}) = 34$ MeV

A. Cunsolo, A. Foti, G. Immè, G. Pappalardo, G. Raciti, and N. Saunier

Phys. Rev. C 24, 2127 (1981) - Published 1 November, 1981

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Energy spectra and angular distributions of tritons from the ${}^{14}C$ ( ${}^{6}{Li}$ , $t$ ) ${}^{17}O$ reaction have been measured at 34 MeV ${}^{6}{Li}$ incident energy and between $θ_{lab} = 5 ° and 45 °$ . The observed selectivity and the forward peaked angular distributions suggest a predominantly direct reaction mechanism. ${}^{17}O$ states with main 3p-2h configuration are tentatively identified. The experimental data have been analyzed in terms of Hauser-Feshbach and exact-finite-range distorted-wave Born-approximation theories. ${}^{3}{He}$ spectroscopic strengths are extracted.

NUCLEAR REACTIONS ${}^{14}C$ ( ${}^{6}{Li}$ , $t$ ) ${}^{17}O$ . $E ({}^{6}{Li}) = 34$ MeV; measured $σ (θ)$ ; ${}^{17}O$ levels ${}^{3}{He}$ spectroscopic strengths extracted. EFR-DWBA and HF analysis.

Spectroscopy of ${}^{204, 206, 208}{Rn}$ and the systematic behavior of $Z = 86$ isotopes

D. Horn, C. Baktash, and C. J. Lister

Phys. Rev. C 24, 2136 (1981) - Published 1 November, 1981

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A spectroscopic investigation of the radon isotopes ${}^{204, 206, 208}{Rn}$ was performed by means of the reactions ${}^{192, 194, 196}{Pt}$ ( ${}^{16}O$ , $4 n$ ) ${}^{204, 206, 208}{Rn}$ and ${}^{197}{Au}$ ( ${}^{14}N$ , $5 n$ ) ${}^{206}{Rn}$ with ${}^{16}O$ energies between 85 and 110 MeV and ${}^{14}N$ energies between 80 and 94 MeV. $γ - γ$ coincidences, pulsed beam yield functions, angular distributions, and pulsed beam isomeric decay rates were measured. The yrast and near-yrast level structure was established to $J \sim 15 ℏ$ , and in each of the three nuclei two isomers above the known $J^{π} = 8^{+}$ state were observed. The systematic trends for the $Z = 86$ isotopes are compared with the behavior expected in a single particle model, and increased collectivity is found with decreasing neutron number. Analogies are made with the $N = 86$ system.

NUCLEAR REACTIONS ${}^{192, 194, 196}{Pt}$ ( ${}^{16}O$ , $4 n$ ), $E = 85 - 110$ MeV; ${}^{197}{Au}$ ( ${}^{14}N$ , $5 n$ ), $E = 80 - 94$ MeV. Measured $I_{γ} (E, t)$ , $I_{γ} (θ)$ , $γ - γ (t)$ . Deduced level sequences, $J^{π}$ , $T_{\frac{1}{2}}$ , transition rates. Continuous and pulsed beams, enriched targets, Ge(Li) detectors.

Direct transfer reaction induced by a 100 MeV ${}^{18}O$ beam on ${}^{27}{Al}$ target nuclei

M. C. Mermaz, J. Barrette, and H. E. Wegner

Phys. Rev. C 24, 2148 (1981) - Published 1 November, 1981

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Nuclei in the range $3 \leq Z \leq 9$ produced by direct transfer reactions induced by 100 MeV ${}^{18}O$ ions on ${}^{27}{Al}$ have been studied between $θ_{lab} = 6 ° and 50 °$ . Few-nucleon-transfer reactions populating continuum states exhibit a strong quasielastic behavior and can be described by an extension of the diffraction model for inelastic processes. On the other hand, heavier-mass-transfer reactions are damped in energy and present the usual characteristics of deep inelastic collisions.

NUCLEAR REACTIONS ${}^{27}{Al}$ ( ${}^{18}O$ , $x$ ), $E_{lab} = 100$ MeV, measured $σ (θ, E, Z, A)$ to continuum states, $6 ° \leq θ_{lab} \leq 50 °$ , $3 \leq Z \leq 9$ , $6 \leq A \leq 19$ , DWBA and diffraction model analysis.

Elastic and inclusive analyzing power of deuterium for 0.8 GeV protons

H. Brody, S. Frankel, W. Frati, and O. B. Van Dyck

Phys. Rev. C 24, 2157 (1981) - Published 1 November, 1981

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Measurements are reported of the analyzing power of deuterium for 0.8 GeV polarized protons covering the inclusive region up to and including elastic $p - d$ scattering for both forward and backward emitted protons.

NUCLEAR STRUCTURE Cumulative effect; backward production; analyzing power; $p - p$ correlations.

Momentum transfer in the fragmentation of Cu by relativistic heavy ions and protons

J. B. Cumming, P. E. Haustein, and H. -C. Hseuh

Phys. Rev. C 24, 2162 (1981) - Published 1 November, 1981

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Mean kinetic properties of selected products from the fragmentation of Cu by ${}^{1}H$ , ${}^{4}{He}$ , and ${}^{12}C$ ions over energies ranging from 0.18 to 28 GeV/nucleon have been determined by the thick-target, thick-catcher technique. Momentum transfer, as inferred from $\frac{F}{B}$ ratios, is observed to occur most efficiently for the lower velocity projectiles. Recoil properties of the target fragments, analyzed using the two step velocity vector model, vary strongly with product mass. Rapidity (or some other velocity related parameter) is the dominant projectile variable which governs momentum transfers to fragments from Cu. This and previous observations of the importance of kinetic energy in determining fragment yields are shown to be consistent with a simple kinematical model for the fragmentation process. Major deviations from such simple behavior are observed for high-energy heavy ions incident on heavy element targets.

NUCLEAR REACTIONS Cu fragmentation by ${}^{1}H$ , ${}^{4}{He}$ , and ${}^{12}C$ , $\frac{T}{A} = 0.18 to 28$ GeV/nucleon, thick target, thick catchers; measured $FW$ , $BW$ , and $PW$ for six selected products: ${}^{24}{Na}$ to ${}^{58}{Co}$ , deduced mean kinetic properties, natural targets, Ge(Li) detectors.

Charge-symmetry breaking in the $n - p$ interaction

A. Gersten

Phys. Rev. C 24, 2174 (1981) - Published 1 November, 1981

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A simplified formalism of evaluating the isospin-violating amplitude of the neutron-proton scattering in terms of the bar phase shifts is presented. The singlet-triplet mixing angles are evaluated for the following effects: electromagnetic contributions, $ω ρ^{0}$ mixing, and neutron-proton mass difference effect in the charged $π$ and $ρ$ one-meson exchanges. The possible difference in the polarization of neutrons and protons is estimated for four lab energies: 200, 325, 500, and 750 MeV.

NUCLEAR REACTIONS $n - p$ scattering $E = 25 - 750$ MeV; singlet-triplet transitions, charge symmetry breaking.

Coulomb excitation of the giant dipole resonance in light-ion inelastic scattering from ${}^{208}{Pb}$

T. Izumoto, Y. -W. Lui, D. H. Youngblood, T. Udagawa, and T. Tamura

Phys. Rev. C 24, 2179 (1981) - Published 1 November, 1981

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A coupled-channel calculation including Coulomb excitation has been done for excitation of the isovector giant dipole resonance in light-ion inelastic scattering from ${}^{208}{Pb}$ at forward angles. It is found that the predicted cross sections for excitation of the giant dipole resonance with alpha inelastic scattering, calculated including Coulomb excitation, are much smaller than the experimental isoscalar giant monopole resonance cross section at incident energies around 100 MeV. The predicted cross section for Coulomb excitation of the giant dipole resonance increases rapidly with increasing incident energy, and the giant dipole and monopole resonance cross sections become comparable above $E_{α} = 300$ MeV. For inelastic scattering of ${}^{3}{He}$ , deuterons, and protons at forward angles, Coulomb excitation of the giant dipole resonance is found to be comparable to the giant monopole resonance cross section at $100 < E^{lab} < 200$ MeV. Coulomb excitation of the giant dipole resonance is strongly inhibited by momentum mismatch between incident and outgoing waves due to the large negative $Q$ values. This mismatch is reduced for lighter projectile masses and higher incident energies. As the giant monopole and dipole resonances are almost coincident, giant dipole resonance excitation must be properly accounted for in studies of the giant monopole resonance.

NUCLEAR REACTIONS Coupled-channel calculation of $σ (θ)$ ; for Coulomb excitation of isovector dipole resonance in ${}^{208}{Pb}$ ; from ( $α$ , $α^{'}$ ), ( ${}^{3}{He}$ , ${}^{3}{He}$ '), ( $d$ , $d^{'}$ ), and ( $p$ , $p^{'}$ ) scattering.

Shell effects on the determination of neutron densities from hadron scattering

W. G. Love, D. Halderson, F. Petrovich, J. A. Carr, and H. McManus

Phys. Rev. C 24, 2188 (1981) - Published 1 November, 1981

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The influence of spin-unsaturated subshells on the coupling between hadronic probes and the target nucleons is studied for the case of elastic scattering. Particular attention is focused on the case of pion scattering from nuclei where the $\vec{σ} \cdot \hat{n}$ term in the pion-nucleon $t$ matrix gives rise to a surface correction term to the $π$ -nucleus optical potential. A closed form expression for this term is given and its effects on a few cases of $π$ -nucleus scattering are estimated. Similar estimates are made for proton-nucleus scattering at 800 MeV bombarding energy.

NUCLEAR REACTIONS Pion-nucleus and proton-nucleus elastic scattering. Estimates of shell effects on determination of neutron densities.

Threshold calculation of the $S$ -wave dispersive pion-nucleus optical potential

R. M. Rockmore

Phys. Rev. C 24, 2193 (1981) - Published 1 November, 1981

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The $S$ -wave dispersive part of the two-body contribution to the pion-nucleus optical potential is calculated at threshold in the scattering length model. Effects of finite range vertices, repulsive short-range correlations, and Fermi averaging are included. While the contribution from $NN$ intermediate states is found to be small and negative for reasonable short-range behavior, in agreement with an earlier calculation by Chai and Riska, the contribution from $N Δ$ intermediate states turns out to be somewhat larger in magnitude and of opposite sign. The resulting threshold parameter $Re B_{0}$ is small and repulsive.

NUCLEAR REACTIONS Calculated $S$ -wave dispersive two-body part of pion-nucleus optical at threshold; $NN$ and $N Δ$ intermediate states; Fermi gas model with $k_{F} = 260$ MeV.

Nuclear spallation-fragmentation reactions induced by high-energy projectiles

X. Campi and J. Hüfner

Phys. Rev. C 24, 2199 (1981) - Published 1 November, 1981

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In a fragmentation or spallation reaction a target nucleus is hit by a high-energy projectile (proton or heavy ion). In the fast step of the reaction highly excited intermediate nuclei, the prefragments, are formed. They decay to the particle stable final fragments in a second step. We treat the first step in Glauber theory. For the decay chain we propose a master equation and solve it by converting it to a differential equation. Analytical solutions are obtained. They clarify the underlying physics: The mass yield curve $σ (A)$ of the final fragments is directly related to the distribution of excitation energy in the prefragments. The isobaric cross sections $σ (A, N - Z)$ for fixed $A$ are dominated by the level density of the final fragment at its lowest particle threshold. Some properties of the target, like its neutron excess, enter via a memory factor. The formulas are successfully compared to the data.

NUCLEAR REACTIONS Spallation and fragmentation reactions; projectile protons of several GeV, various targets; theory for cross sections; two step model; fast step Glauber theory; analytical formula for evaporation chains.

Reactive content of the Klein-Gordon optical potential

D. J. Ernst and Mikkel B. Johnson

Phys. Rev. C 24, 2210 (1981) - Published 1 November, 1981

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The reactive content of the pion-nucleus optical potential is explicated in the Klein-Gordon and relativistic Schrödinger theories. It is proven that even though the solution of the Klein-Gordon equation introduces intermediate multipion states, there is no inelastic contribution of these states to the scattering amplitudes. This is shown to come about from an intricate cancellation between diagrams which contain different numbers of pions at specific intermediate times. Approximation schemes which expand the optical potential of the relativistic Schrödinger equation in terms of a fixed number of pions present at a given time are shown not to maintain this cancellation whenever truncated at any finite order of perturbation theory.

NUCLEAR REACTIONS Reactive content of relativistic Schrödinger and Klein-Gordon equations are compared. Expansion in terms of fixed numbers of intermediate meson states is shown to lead to pathological results.

${}^{81}{Br}$ and ${}^{79}{Br}$ as detectors of solar neutrinos

John N. Bahcall

Phys. Rev. C 24, 2216 (1981) - Published 1 November, 1981

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Uncertainties in nuclear matrix elements that are important for the interpretation of proposed bromine solar neutrino experiments are evaluated. Some laboratory measurements that could reduce these uncertainties are suggested. The question of what can be learned about the interior of the sun by performing a bromine solar neutrino experiment is discussed with the aid of neutrino absorption cross sections that are calculated using simplifying assumptions.

RADIOACTIVITY ${}^{79}{Br}$ , ${}^{81}{Br}$ calculated neutrino absorption cross sections. ${}^{81}{Kr}$ excited states considered.

Nuclear magnetic moment of 2.8 d ${}^{111}{In}$

E. Hagn and E. Zech

Phys. Rev. C 24, 2222 (1981) - Published 1 November, 1981

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The hyperfine interaction of ${}^{111}{In}$ ( $j^{π} = \frac{9}{2^{+}}$ , $T_{\frac{1}{2}} = 2.8$ d) in Fe has been investigated with nuclear magnetic resonance on oriented nuclei at temperatures of ∼0.01 K. The magnetic hyperfine splitting $ν_{M} = | \frac{g μ_{N} B_{HF}}{h} |$ and the resonance shift with an external magnetic field were measured as 267.2(2) MHz and -0.906(18) MHz/kG, respectively. With the known hyperfine field $B_{HF} = - 286.6 (5)$ kG the nuclear magnetic moment is deduced to be $μ = (+) 5.504 (10) μ_{N}$ . The differential resonance displacements of the 171- and 245-keV resonances measured at $θ = 0 ° and 90 °$ were found to be $\bar{ν} (0 °, 171) - \bar{ν} (0 °, 245) = - 3 (13)$ kHz and $\bar{ν} (0 °, 245) - \bar{ν} (90 °, 245) = + 3 (30)$ kHz. Taking into account these data the quadrupole splitting $ν_{Q} = \frac{e^{2} qQ}{h}$ of ${}^{111}{InFe}$ is estimated to be -0.3(1.1) MHz.

RADIOACTIVITY ${}^{111}{In}$ [from ${}^{109}{Ag}$ ( $α$ , 2n)]; measured $I_{γ} (θ, T, ν)$ of oriented states; NMR on oriented nuclei. Deduced $g$ , $μ$ , Knight shift. Recoil implantation into Fe.

${}^{131}{Sn}$ decay

H. Huck, M. L. Pérez, J. J. Rossi, and H. M. Sofía

Phys. Rev. C 24, 2227 (1981) - Published 1 November, 1981

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A level scheme for ${}^{131}{Sb}$ is proposed taking into account the gamma-ray energy and intensity and the gamma-gamma coincidences obtained in the decay of ${}^{131}{Sn}$ . The samples were obtained using on-line mass-separation techniques applied to ${}^{235}U$ thermal-neutron fission products. The half-life of ${}^{131}{Sn}$ was measured to be 61±1 s. The level structure in ${}^{131}{Sb}$ is compared with a particle-core coupling calculation using a quadrupole protonneutron interaction.

RADIOACTIVITY ${}^{131}{Sn}$ (from ${}^{235}U$ ( $n_{th}$ , $f$ ); measured $E_{γ}$ , $I_{γ}$ , $γ - γ$ coincidences and $T_{\frac{1}{2}}$ of ${}^{131}{Sn}$ , Ge(Li), and Ge intrinsic detectors; ${}^{131}{Sb}$ deduced levels and $β$ branches. Mass-separated ${}^{131}{Sn}$ and ${}^{131}{Sb}$ activities.

Gamow-Teller strength in the ${}^{14}O$ → ${}^{14}N$ (3.948 MeV) beta decay

A. M. Hernandez and W. W. Daehnick

Phys. Rev. C 24, 2235 (1981) - Published 1 November, 1981

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The Gamow-Teller $β$ decay from the ${}^{14}O$ $0^{+}$ ground state to the 3.948 MeV $1^{+}$ level in ${}^{14}N$ has been studied by observing $γ$ rays from the deexcitation of the 3.948 and 2.313 MeV levels in ${}^{14}N$ . We measured a branching ratio of (5.28 ± 0.23) × $10^{- 14}$ relative to the superallowed Fermi decay to the 2.313 MeV level, and deduce $f t = 1446 \pm 63$ . The corresponding Gamow-Teller transition strength is $B (GT) = 2.73 \pm 0.12$ . This value is about 40% lower than predicted by several widely used shell model calculations, and may suggest appreciable quenching by mesonic currents.

RADIOACTIVITY ${}^{14}O$ measured $I_{γ}$ , GT strength.

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Recent Articles

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Recent Issues

Spectroscopy of excited states in ${}^{102}{Mo}$ and ${}^{106}{Ru}$

Fast protons and alpha particles from the ${}^{12}C$ + ${}^{60}{Ni}$ reaction

Production of the neutron-rich nuclides ${}^{20}C$ and ${}^{27}F$ by fragmentation of 213 MeV/nucleon ${}^{48}{Ca}$

Gyromagnetic ratios of low-lying excited states in ${}^{196}{Pt}$

${}^{209}{Bi}$ + ${}^{136}{Xe}$ reaction at $E_{lab} = 1422$ MeV

${}^{14}C$ ( ${}^{6}{Li}$ , $t$ ) ${}^{17}O$ reaction at $E ({}^{6}{Li}) = 34$ MeV

Spectroscopy of ${}^{204, 206, 208}{Rn}$ and the systematic behavior of $Z = 86$ isotopes

Direct transfer reaction induced by a 100 MeV ${}^{18}O$ beam on ${}^{27}{Al}$ target nuclei

Elastic and inclusive analyzing power of deuterium for 0.8 GeV protons

Momentum transfer in the fragmentation of Cu by relativistic heavy ions and protons

Charge-symmetry breaking in the $n - p$ interaction

Coulomb excitation of the giant dipole resonance in light-ion inelastic scattering from ${}^{208}{Pb}$

Shell effects on the determination of neutron densities from hadron scattering

Threshold calculation of the $S$ -wave dispersive pion-nucleus optical potential

Nuclear spallation-fragmentation reactions induced by high-energy projectiles

Reactive content of the Klein-Gordon optical potential

${}^{81}{Br}$ and ${}^{79}{Br}$ as detectors of solar neutrinos

Nuclear magnetic moment of 2.8 d ${}^{111}{In}$

${}^{131}{Sn}$ decay

Gamow-Teller strength in the ${}^{14}O$ → ${}^{14}N$ (3.948 MeV) beta decay

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