P.D. Kunz

Role of tensor force in charge exchange reactions

Abstract The discrepancy between theory and experiment in the analysis of the 54 Fe( 3 He, t) 54 Co reaction is removed by including tensor force in the effective interaction.

Microscopic calculations for (p, n) reactions to isobaric analogue states

Abstract Calculations of (p, n) transitions to 0+ isobaric analogue states have been made taking into account the (p, d) (d, n) contribution as well as the usual charge exchange. Satisfactory agreement in shape between calculated and experimental angular distributions is obtained over a broad range of target nuclei and proton energies and the resulting strengths needed to reproduce magnitudes are much more consistent than when the two-step mechanism is omitted.

On two-step processes via particle transfer channels

Abstract Two-step processes via particle transfer channels are formulated without employing the post-prior approximation. It is shown that this approximation leads to erroneous conclusions which seriously overestimate the effect of higher order processes.

Finite-range effects in multi-step (p-d, d-n) reactions☆

Abstract A semi-quantitative discussion is given which suggests that finite-range effects should be large in second order particle-transfer calculations when the first order term is large. The results of a full finite-range calculation for 58 Ni(p-d, d-n) 58 Cu, which support the semi-quantitative argument, are presented.

The effect of pickup-stripping contributions on the selection of a unique 3He optical potential☆

Abstract The coupling of pickup-stripping channels in 3 He elastic scattering has been shown to have a large effect on the elastic cross section at back angles for higher projectile energies. Quantitative treatment of these effects leads to the conclusion that the “deep” family of mass-3 optical potentials is selected by fitting to high energy, back angle elastic scattering data. This is in contrast to recent optical model studies which have concluded that such data can be fit only by using a “shallow” potential. Consistency is now found between those mass-3 potential families required in certain reaction studies and those indicated for elastic scattering.

Study of the effective two-body force using the 54Fe(3He, t) charge exchange reaction☆

Abstract Differential cross sections were measured for the 54Fe(3He, t)54Co reaction at 37.5 MeV. The T = 1 states are well described using a conventional microscopic DWBA analysis with ( f 7 2 ) −2 orbitals but similar analysis of the T = 0 states indicates a serious discrepancy between theoey and experiment.

Is (3He,t) primarily A (3He,α) (α,t) reaction?

Abstract The reaction 48 Ca( 3 He, t) 48 Sc to the low-lying even spin states has been studied as a pure sequential ( 3 He, α) (α,t) process using an exact finite-range formalism. It is found that the strength of the cross-sections to these states is under-predicted by large factors. The consideration of second-order processes via the inelastic channels also fails to account for the strength of these states. The ( 3 He, t) discrepancy still exists.

The effect of p-h corrections on the proton pairing vibrations at Z=50☆

Abstract Recent experimental results from Cd( 3 He, n)Sn reactions on a variety of Cd targets indicate that the proton pairing vibration lies at an excitation energy nearly 2 MeV below the value suggested by binding energy systematics. It is shown here that this large discrepancy, which is in contrast to the case of neutron pairing vibrations, may be explained by the effects of particle-hole (p-h) interactions which are large because of the Coulomb contribution. The p-h matrix elements are obtained empirically from observed p-h separations and also calculated theoretically for both Coulomb and nuclear contributions. These average empirical matrix elements from the Cd experiments give excellent agreement to the 2p-1h states in the 115 In( 3 He, n) experiment populated via L =0 transfers. The agreement in the latter case indicates a simple scaling of the interaction with the number of particles and holes.

The absolute normalization of three-nucleon transfer reactions☆

Abstract Data for (α, p) and (6Li, t) reactions on 40Ca targets are re-analyzed using microscopic form factors and the DWBA in exact range. The absolute magnitudes predicted for (6Li, t) cross sections agree with data, while the (α, p) cross sections calculated with a deep alpha particle optical model are more than one hundred times smaller than data. The agreement for (α,p) magnitudes is greatly improved when a shallow optical potentials is used.

On the influence of recoil effects in the microscopic description of inelastic scattering

Abstract A method is presented to calculate the influence of recoil effects in the microscopic description of inelastic scattering. Examples for two simple test cases are given.