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The p - p-chain reaction 3He(α, γ)7Be can sensitively influence the prediction of the 7Be and 8B neutrino fluxes. Despite its importance, the knowledge of its reaction cross section at energies of the core of the Sun (15 keV 30 keV) is limited and the accuracy far from the desired 3% level. In the present paper the indirect measurement of the external capture contribution using the asymptotic normalization coefficient (ANC) technique is reported. The angular distributions of deuterons emitted in the 6Li(3He,d)7Be α-transfer reactions were measured and the ANCs extracted from the scaling of distorted-wave Born approximation (DWBA) and coupled-channel (CC) calculations. Then, the astrophysical S-factor for the 3He(α, γ)7Be reaction was calculated assuming E1 direct capture and the zero energy value turned out to be 0.534 0.025 keVb. Both our experimental and theoretical approaches were benchmarked through the analysis of the 6Li(p,γ)7Be astrophysical factor, with interesting astrophysical applications to the understanding of the primordial lithium problem. In particular, the present work disfavors the occurrence of a claimed 200 keV resonance in the astrophysical factor.

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The angular distributions of 13 C elastically scattered by 9 Be nuclei were measured at E Lab ( 13 C) = 16.25 and 19.5 MeV. The measured angular distributions were analyzed via the optical model and the DWBA within the coupled reaction channels methods. In addition to this, the previously obtained data were reanalyzed at energies E Lab = 22.75, 28.12, 36.15, 57.77 and 72.88 MeV. The aim of the study was to elucidate the role of the α -cluster transfer mechanism in the large-angle scattering. As a result of these calculations, the optimal parameters of the potentials and their energy dependence were obtained for 13 C+ 9 Be nuclear system. The data at the backward angles are fairly well reproduced. The spectroscopic amplitudes were extracted for the 13 C → 9 Be + α configuration at various energies. The results are compared with previously reported values. [ABSTRACT FROM AUTHOR]

Differential cross sections of elastic and inelastic scattering with excitation of states of the rotational band of the ground state of 24 Mg were measured at an α -particle energy of 50.5 MeV and 3 He 60 MeV. The angular distributions were analyzed using an optical model and a coupled channel method. A number of potentials with significantly different geometries are obtained, which describe well the elastic scattering at the measured angular range. The collective model was used in the calculations via the coupled channel method. In addition to the ground state, three low-lying states of 24 Mg, 2 + (1.368 MeV), 4 + (4.122 MeV), and 4.238 MeV (2 + ), were included in the coupling scheme. The values of quadrupole ( β 2 ) and hexadecapole ( β 4 ) deformation parameters were extracted. According to the analysis of scattering of α -particles, they are 0.52 and 0.05. For 3 He, they are 0.75 and 0.07, respectively. The extracted parameters correspond to the previously obtained values from the scattering of protons, deuterons and α -particles. [ABSTRACT FROM AUTHOR]

Complete angular distributions including both forward and backward angles are reported for the 14C(11B,10B)15C reaction at Elab(11B)=45 MeV for the ground and excited states of 10B and 15C. The experimental data were analyzed within the coupled reaction channels method that included the 11B+14C elastic scattering channel as well as channels for one- and twostep transfers of nucleons in the coupling scheme. The necessary 11B+14C optical potential parameters were obtained from previous work, while those for 10B+15C were deduced from fitting the CRC reaction calculations to the 14C(11B,10B)15C reaction data. Needed spectroscopic amplitudes of transferred nucleons and clusters were calculated within the translationalinvariant shell model. The data are well described by neutron transfers, while contributions from two-step transfers were found to be negligible. Recently published global optical potentials for the elastic scattering of the 8;10;11B isotopes were tested as part of the analysis and found to satisfactorily describe this reaction data if the surface imaginary potentials were omitted for both the entrance and the exit channels, and the parameters for volume real and imaginary potentials were slightly modified. [ABSTRACT FROM AUTHOR]

Complete angular distributions including both forward and backward angles are reported for the reaction 13C(11B, 12C)12B at Elab(11B) = 45 MeV leading to the ground and excited states of 12C and 12B. This reaction explores the interplay of proton and neutron transfers as well of those for larger clusters. The experimental data were analyzed within the coupled-reaction-channels method (CRC) that included the 13C+11B elastic scattering channel as well as channels for one- and two-step transfers of nucleons in the coupling scheme. The necessary 13C+11B optical potential parameters were obtained from previous work, while those for 12C + 12B were deduced from fitting the calculations to the 13C(11B, 12C)12B reaction data. Needed spectroscopic amplitudes of transferred nucleons and clusters were calculated within the translational-invariant shell model (TISM). The data are well-described by proton transfers while contributions from neutron transfer are only important at the largest angles. New global optical potentials for the elastic scattering of 8,10,11B isotopes were tested and found to describe the forward angles reaction data but not those for the middle and larger angles even when the ground-state reorientation of 11B in the entrance channel is included. [ABSTRACT FROM AUTHOR]

Elastic scattering angular distribution was measured for the 10B+12C system at Elab= 17.5MeV in the angular range ofθcm= 15°–165°. The analysis of the experimental data was carried out in the framework of the optical model and the distorted-wave method (FRDWBA) using the FRESCO code. The optical model describes well the experimental crosssections in the region of the angles of the forward hemisphere, but it is notable to reproduce the observed rise of the cross sections at large angles. Only accounting for the exchange mechanism with a deuteron transfer allows us to describe the experiment in the full angular range. Spectroscopicamplitude has been extracted from the analysis for the 12C→10B +dconfiguration [ABSTRACT FROM AUTHOR]

Angular distribution of the 1 0 B + 1 2 C elastic scattering was measured at E lab ( 1 0 B) = 4 1. 3 MeV. Experimental data showed a significant increase in differential cross-sections at backward angles. The optical model with phenomenological potentials reproduces well the experimental cross-sections in the region of the angles of the forward hemisphere, but is not able to explain the increase in cross-sections at large angles. The distorted wave Born approximation method was used to reproduce the experimental data at large angles (> 9 0 ∘) by taking into consideration a deuteron transfer. Spectroscopic amplitude has been extracted for the configuration 1 2 C → 1 0 B + d from the analysis. [ABSTRACT FROM AUTHOR]

Angular distributions of the 15N+12C elastic and inelastic scattering were measured at Elab(15N) = 81 MeV to study the nuclear-nuclear interactions and possible transfer contributions to the scattering. The data were analyzed with the coupled-reaction-channels (CRC) method using the 15N+12C optical potential ofWoods-Saxon shape. The elastic and inelastic scattering as well as the most obvious one- and two-step transfer reactions were included in the channel-coupling scheme. The 15N+12C optical potential and deformation parameters of 15N were deduced. The transfer reaction contributions to the 15N+12C elastic and inelastic scattering channels were estimated. The 15N+12C elastic scattering at 81 MeV was compared with the 14N+12C elastic scattering of 14N beam energy 78 MeV. [ABSTRACT FROM AUTHOR]

Angular distributions of scattered deuterons on 7Li nuclei with excitation of the 0.478 MeV (Jπ = 1=2-) level and tritons from the 7Li(d,t)6Li reaction with transitions to the ground (1+) state of 6Li were measured at 14.5 MeV. Analysis of the experimental data was performed in the framework of the optical model and the coupled reaction channels method with taking into account the - and n-transfer mechanisms. The values of the spectroscopic factors and the deformation parameters for the 7Li, 6Li were extracted. [ABSTRACT FROM AUTHOR]