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Two-nucleon transfer reactions are essential tools to investigate specific features of the nuclear structure, such as the correlation among valence particles in the transfer process. Besides, transfer reactions may be an important channel to take into account in charge-exchange processes since they can represent a competing contribution to the final cross section. The two-proton pickup transfer reaction $^{40}\mathrm{Ca}(^{18}\mathrm{O},^{20}\mathrm{Ne})\phantom{\rule{0.16em}{0ex}}^{38}\mathrm{Ar}$ has been measured at 270 MeV, and the angular distributions for transitions to different excited states extracted. This paper shows the analysis of the data performed by finite-range coupled reaction channel and coupled-channel Born approximation methods. Extensive shell-model calculations are performed to derive the one- and two-proton spectroscopic amplitudes for the projectile and target overlaps. The role of the simultaneous and sequential two-proton transfer mechanisms to populate the measured final states or groups of states, mainly characterized by a high collectivity, is also discussed.

\textbf{Background:} The influence of halo structure of $^6$He, $^8$B, $^{11}$Be and $^{11}$Li nuclei in several mechanisms such as direct reactions and fusion is already established, although not completely understood. The influence of the $^{10}$C Brunnian structure is less known. \textbf{Purpose:} To investigate the influence of the cluster configuration of $^{10}$C on the elastic scattering at an energy close to the Coulomb barrier. \textbf{Methods:} We present experimental data for the elastic scattering of the $^{10}$C+$^{208}$Pb system at $E_{\rm lab}$ = 66~MeV. The data are compared to the three- and the four-body continuum-discretized coupled-channels calculations assuming $^9$B+$p$, $^6$Be+$\alpha$ and $^8$Be+$p$+$p$ configurations. \textbf{Results:} The experimental angular distribution of the cross sections shows the suppression of the Fresnel peak that is reasonably well reproduced by the continuum-discretized coupled-channels calculations. However, the calculations underestimate the cross sections at backward angles. Couplings to continuum states represent a small effect. \textbf{Conclusions:} The cluster configurations of $^{10}$C assumed in the present work are able to describe some of the features of the data. In order to explain the data at backward angles, experimental data for the breakup and an extension of theoretical formalism towards a four-body cluster seem to be in need to reproduce the measured angular distribution.

Quasi-elastic scattering angular distribution for the $$94.5\ \hbox {MeV}\ ^{17}\hbox {F}$$ radioactive ion beam on the $$^{208}\hbox {Pb}$$ target has been measured. To describe the experimental quasi-elastic scattering angular distribution and explore the reaction dynamic, firstly, the optical potentials with the double-folding Sao Paulo and Akyuz Winther potentials for both real and imaginary parts were used to analyze the experimental data. It is observed that both theoretical angular distributions are very similar. The optical model results describe reasonably the experimental data until 100 $$^\circ $$ but underpredict the data for larger angles. Secondly, the continuum discretized coupled channel method (CDCC) was used to study the effect of the breakup channel on the elastic scattering. The double-folding Sao Paulo and Akyuz Winther potentials were used as nuclear interactions giving again similar results. The agreement with the data is slightly improved at intermediate angles. The sensibility of the CDCC effects upon the nuclear interaction potential was checked. Finally, the influence of inelastic states of both projectile and target, the one-proton, one-neutron, two-neutron and $$\alpha $$ transfer channels on the quasi-elastic scattering angular distribution is analyzed in the frame of the coupled channel and coupled reaction channel methods, respectively. It is observed that the coupling to the first excited state of $$^{17}\hbox {F}$$ is the one that affects more the elastic scattering, although the inelastic channels of the target also influence it when compared with the optical model results. The effect of the transfer channels on the quasi-elastic angular distribution is negligible.

Motivated by the strong synergy between structure and nuclear reactions we have performed a phenomenological analysis using available elastic scattering data for collisions of tightly-bound ( $$^{10}\hbox {Be}$$ , $$^{10}\hbox {B}$$ , $$^{10}\hbox {C}$$ , $$^{11}\hbox {B}$$ , $$^{12}\hbox {C}$$ , $$^{16}\hbox {O}$$ ), weakly-bound ( $$^6\hbox {Li}$$ , $$^7\hbox {Li}$$ , $$^8\hbox {Li}$$ , $$^9\hbox {Be}$$ ), and exotic ( $$^6\hbox {He}$$ , $$^{8}\hbox {B}$$ and $$^{11}\hbox {Be}$$ ) nuclei on $$^{58}\hbox {Ni}$$ and $$^{64}\hbox {Zn}$$ targets at energies close to the Coulomb barrier. After a proper reduction, the cluster configuration and dynamics effects in the total reaction cross section are discussed. Also, an approach based on the interaction distances is used to investigate static and dynamic effects in the elastic scattering of light nuclei. A correlation between the critical interaction distance and binding energy for a given configuration is observed.

Gamma-ray angular distributions in oriented $$^{92}$$ Mo produced via the $$^{6}$$ Li+ $$^{89}$$ Y reaction were studied in this work. The characteristic $$\gamma $$ rays in $$^{92}$$ Mo were measured by means of the GALILEO array, which is composed of 25 Compton-suppressed HPGe detectors arranged in a nearly 2 $$\pi $$ geometry. A detailed analysis of the spin-alignment attenuation factors ( $$\alpha _2$$ ) for different excited states in $$^{92}$$ Mo was performed, by analyzing the measured angular distribution coefficients of several pure-E2 transitions. The relationship between $$\alpha _2$$ and the spin was established in $$^{92}$$ Mo and the 244-keV transition between the 5 $$^-_1$$ and 4 $$^+_1$$ states resulted to have a E1 + M2 character with a mixing ratio ( $$\delta $$ ) of $$-0.05^{+0.05}_{-0.06}$$ , consistent with shell model calculations.

In this contribution, we report on effects due to the cluster configuration of boron isotopes, \(^8\)B, \(^{10}\)B, \(^{11}\)B and \(^{12}\)B, in the elastic scattering on \(^{58}\)Ni target at energies close to the Coulomb barrier. The results of coupled channel calculations, where the different configurations of the boron isotopes, \(^8\)B \(=\) \(^7\)Be\(+\)p, \(^{10}\)B \(=\) \(^6\)Li\(+\) \(\alpha \), \(^{11}\)B \(=\) \(^7\)Li\(+\) \(\alpha \) and \(^{12}\)B \(=\) \(^{11}\)B\(+\)n, have been attributed to different effects in the angular distributions for the elastic scattering process, are present.

Direct measurements of the total fusion cross section for B 8 + 40 Ar were achieved with the active target technique. The fusion excitation function was extracted at energies near the Coulomb barrier. The cross section is well described by a coupled reaction channels calculation. The data were compared with previous B 8 fusion experiments on Si 28 and Ni 58 targets. No evidence of striking enhancement of the total fusion cross section at near the Coulomb barrier, that was previously reported for the B 8 + 58 Ni system, was observed in these direct measurements. The present data are systematically consistent with the results for B 8 + 28 Si at higher energies and with other weakly-bound systems at near-barrier energies.

The elastic scattering of the radioactive proton-rich carbon isotope $^{10}\mathrm{C}$ has been investigated. A full differential angular distribution for the elastic scattering of $^{10}\mathrm{C}$ on a $^{58}\mathrm{Ni}$ target has been measured at ${E}_{\mathrm{Lab}}=35.3$ MeV, which is just above the Coulomb barrier for this system (${V}_{B}=27$ MeV). The obtained angular distribution was analyzed in terms of coupled-channels, coupled-reaction-channels, and continuum-discretized coupled-channels calculations. In the coupled-channels calculation, several inelastic transitions of the target and the first (${2}^{+}$) excited state of the $^{10}\mathrm{C}$ projectile were considered. The coupling to the first (${2}^{+}$) excited state of $^{10}\mathrm{C}$ was shown to be very important to describe the rising of the cross section at backward angles. We also performed an analysis with the continuum-discretized coupled channels, considering the $^{9}\mathrm{B}+p$ and $^{6}\mathrm{Be}+\ensuremath{\alpha}$ channels, which indicated a strong cluster configuration for the $^{10}\mathrm{C}$ projectile.

Elastic scattering of a radioactive neutron-rich boron isotope, $^{12}\mathrm{B}$, has been measured for the first time. Angular distributions for the elastic scattering of $^{12}\mathrm{B}+^{58}\mathrm{Ni}$ have been measured at ${\mathit{E}}_{\mathrm{Lab}}=30.0$ and 33.0 MeV, which are just above the Coulomb barrier (${\mathit{V}}_{\mathrm{B}}=24$ MeV). The obtained angular distributions were analyzed in terms of the large-scale coupled channel (CC) and coupled reaction channel (CRC) calculations, where several inelastic transitions for the target, as well as the most relevant transfer reactions, have been included in the coupling matrix elements. The roles of the spin reorientation and spin-orbit interaction in the reaction mechanism were also investigated. The one-neutron transfer reaction through a coupled reaction calculation had some effect on the elastic scattering of the system studied.

In this work, we study the effect of paring correlation on the two-neutron transfer reaction \(^{28}\)Si(\(^{18}\)O,\(^{16}\)O)\(^{30}\)Si at 84 MeV incident energy in the laboratory frame. For this, coupled reaction channel (CRC) and coupled channel Born approximation (CCBA) calculations were performed considering the cluster, independent coordinates and sequential transfer models for two-neutron transfer. For the calculation of the spectroscopic amplitudes the NuShellX (http://www.garsington.eclipse.co.uk/, [1]) code was used.

Background: Recently, a systematic exploration of two-neutron transfer induced by the $(^{18}\mathrm{O},\phantom{\rule{0.16em}{0ex}}^{16}\mathrm{O})$ reaction on different targets has been performed. The high-resolution data have been collected at the MAGNEX magnetic spectrometer of the INFN-LNS Laboratory in Catania and analyzed with the coupled reaction channel (CRC) approach. The simultaneous and sequential transfers of the two neutrons have been considered under the same theoretical framework without the need for adjustable factors in the calculations.Purpose: A detailed analysis of the one-neutron transfer cross sections is important to study the sequential two-neutron transfer. Here, we examine the $(^{18}\mathrm{O},\phantom{\rule{0.16em}{0ex}}^{17}\mathrm{O})$ reaction on $^{16}\mathrm{O},\phantom{\rule{0.28em}{0ex}}^{28}\mathrm{Si}$, and $^{64}\mathrm{Ni}$ targets. These even-even nuclei allow for investigation of one-neutron transfer in distinct nuclear shell spaces.Method: The MAGNEX spectrometer was used to measure mass spectra of ejectiles and extract differential cross sections of one-neutron transfer to low-lying states. We adopted the same CRC formalism used in the sequential two-neutron transfer, including relevant channels and using spectroscopic amplitudes obtained from shell-model calculations. We also compare with the one-step distorted-wave Born approximation (DWBA).Results: For the $^{18}\mathrm{O}+^{16}\mathrm{O}$ and the $^{18}\mathrm{O}+^{28}\mathrm{O}$ systems, we used two interactions in the shell model. The experimental angular distributions are reasonably well reproduced by the CRC calculations. In the $^{18}\mathrm{O}+^{64}\mathrm{Ni}$ system, we considered only one interaction, and the theoretical curve describes the shape and order of magnitude observed in the experimental data.Conclusions: Comparisons between experimental DWBA and CRC angle-integrated cross sections suggest that excitations before or after the transfer of a neutron are relevant in the $^{18}\mathrm{O}+^{16}\mathrm{O}$ and $^{18}\mathrm{O}+^{64}\mathrm{Ni}$ systems.

We present a brief review of the reaction mechanisms involved in collisions of weakly bound projectiles with tightly bound targets, at near-barrier energies. We discuss systematic behaviors of the data, with emphasis in fusion, breakup, nucleon transfer and elastic scattering. The dependence of the breakup cross section on the charge and mass of the target is discussed, and the influence of the breakup channel on complete fusion is investigated. For this purpose, we compare reduced fusion cross sections with a benchmark universal curve. The behaviors observed in the comparisons are explained in terms of polarization potentials and of nucleon transfer followed by breakup. The influence of the breakup process on elastic scattering is also discussed. Some apparent contradictions between results of different authors are explained and some perspectives of the field are presented.

To obtain the neutron spectroscopic amplitudes for 90-96Zr overlaps, experimental data of elastic scattering with small experimental errors and precise optical potentials were analyzed. In this study, the elastic scattering angular distributions of C + (A = 90, 91, 92, 94, 96) were measured using the high-precision Q3D magnetic spectrometer in the Tandem accelerator. The São Paulo potential was used for the optical potential. The optical model and coupled channel calculations were compared with the experimental data. The theoretical results were found to be very close to the experimental data. In addition, the possible effects of the couplings to the inelastic channels of the targets and C projectiles on the elastic scattering were studied. It was observed that the couplings to the inelastic channels of the C projectiles could improve the agreement with the experimental data, while the inelastic couplings to the target states are of minor importance. The effect of the one-neutron stripping in the C+ elastic scattering was also studied. The one-neutron stripping channel in C + was found to be not relevant and did not affect the elastic scattering angular distributions. Our results also show that in the reactions with the considered zirconium isotopes, the presence of the extra neutron in C does not influence the reaction mechanism, which is governed by the collective excitation of the C core.

In this paper, we analyze the one-neutron pick-up from the 55Mn target when it is bombarded by 17MeV deuteron, by performing coupled reaction channel (CRC) calculations. Spectroscopic amplitudes for CRC calculations, and structural information such as reduced B(E2) transition probabilities, quadrupole, and magnetic momenta, are obtained from shell-model calculations using the fp-kb3 interaction. The calculated structure quantities are in good agreement with the available experimental data for both target and ejectile. Analyses of angular distributions show the relevance of microscopic information for the description of the higher excited states of 54Mn .

In this work we study the simultaneous and sequential two-neutron transfer mechanisms to the $^{28}\mathrm{Si}$ nucleus induced by $(t,p)$ and $(^{18}\mathrm{O},^{16}\mathrm{O})$ reactions. New experimental cross sections for the $^{28}\mathrm{Si}(^{18}\mathrm{O},^{16}\mathrm{O})^{30}\mathrm{Si}$ reaction at 84 MeV are also presented. Direct reaction calculations are carried out within the exact finite range coupled reaction channel, for the simultaneous transfer of the two-neutron cluster, and the second-order distorted wave Born approximation, for the sequential transfer. Two different models are considered to describe the two-neutron cluster. The spectroscopic information was obtained from a shell-model calculation with a psdmod interaction for the target overlaps where the $1{p}_{3/2}, 1{p}_{1/2}, 1{d}_{3/2}, 1{d}_{5/2}$, and $2{s}_{1/2}$ orbitals are included as valence subspace. We show that simultaneous and sequential two-neutron transfers are competing mechanisms for the population of the ground state in $^{30}\mathrm{Si}$. A systematic analysis of the two-neutron transfer induced by the $(^{18}\mathrm{O},^{16}\mathrm{O})$ reaction indicates that the static deformation of target nuclei impacts the two-neutron transfer mechanism.

The measurement of one-neutron stripping cross sections for the $^{89}\mathrm{Y}(^{6}\mathrm{Li},^{5}\mathrm{Li})^{90}\mathrm{Y}^{*}$ reaction at 22 MeV and 34 MeV is reported, using both in-beam and off-beam $\ensuremath{\gamma}$-ray spectroscopy methods. Characteristic $\ensuremath{\gamma}$ lines of $^{90}\mathrm{Y}$ are clearly identified by both the $\ensuremath{\gamma}\text{\ensuremath{-}}\ensuremath{\gamma}$ and proton-$\ensuremath{\gamma}$ coincidence methods. The obtained cross section of one-neutron stripping at 34 MeV is found to be much smaller than that at 22 MeV. The one-neutron stripping cross sections measured for this system have the same order of magnitude as the one measured for the same reaction for the $^{6}\mathrm{Li}+^{96}\mathrm{Zr}$ system at energies around the Coulomb barrier. Parameter-free coupled reaction channel calculations agree quite well with the experimental data. Theoretical study of the effect of the one-neutron transfer on the elastic total fusion cross section is performed.

Recently, various two-neutron transfer studies using the $(^{18}\mathrm{O},^{16}\mathrm{O})$ reaction were performed with a large success. This was achieved because of a combined use of the microscopic quantum description of the reaction mechanism and of the nuclear structure. In the present work we use this methodology to study the two-neutron transfer reaction of the $^{18}\mathrm{O}+^{64}\mathrm{Ni}$ system at 84 MeV incident energy, to the ground and first ${2}^{+}$ excited state of the residual $^{66}\mathrm{Ni}$ nucleus. All the experimental data were measured by the large acceptance MAGNEX spectrometer at the Instituto Nazionale di Fisica Nucleare --Laboratori Nazionali del Sud (Italy). We have performed exact finite range cross section calculations using the coupled channel Born approximation (CCBA) and coupled reaction channel (CRC) method for the sequential and direct two-neutron transfers, respectively. Moreover, this is the first time that the formalism of the microscopic interaction boson model (IBM-2) was applied to a two-neutron transfer reaction. From our results we conclude that for two-neutron transfer to the ground state of $^{66}\mathrm{Ni}$, the direct transfer is the dominant reaction mechanism, whereas for the transfer to the first excited state of $^{66}\mathrm{Ni}$, the sequential process dominates. A competition between long-range and short-range correlations is discussed, in particular, how the use of two different models (Shell model and IBM's) help to disentangle long- and short-range correlations.

We have measured the elastic scattering cross-section for 8Li + 9Be and 8Li + 51V systems at 19.6MeV and 18.5MeV, respectively. We have also extracted total reaction cross sections from the elastic scattering analysis for several light weakly bound systems using the optical model with Woods-Saxon and double-folding-type potentials. Different reduction methods for the total reaction cross-sections have been applied to analyze and compare simultaneously all the systems.

We present a trial to obtain a systematic behavior of the results available in the literature on the complete and incomplete fusion induced by the weakly bound projectile ${}^{9}$Be on targets with different masses and/or charges. We stress that although the incomplete-fusion probability and the complete-fusion suppression are very closely related quantities, the first is an experimental value whereas the later is model dependent. A trend of systematic behavior for the incomplete-fusion probability as a function of the target charge is achieved, but not for the complete-fusion suppression.

We have measured the elastic scattering of the weakly bound $^{6}\mathrm{Li}$ on the $^{116,112}\mathrm{Sn}$ targets, at energies close to the Coulomb barrier. The energy dependence of the interaction potential has been investigated by two different methods and the presence of the breakup threshold anomaly is observed. We have also derived the total reaction cross sections for the above systems and compared them to those of other systems with halo, weakly bound, and tightly bound projectiles on targets with similar masses. The reaction cross sections are largest for systems with halo nuclei, then the systems with no-halo weakly bound nuclei, and the smallest cross sections are those for tightly bound systems.