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The global α -nucleus optical model is studied based on the nucleon self-energies in an Dirac-Brueckner-Hartree-Fock (DBHF) approach. The newly developed nucleon-nucleus optical model CTOM derived from DBHF, is used as the basis to consistently generate the real and imaginary potentials of the α -nucleus optical potential by double-folding model. The same range correction a of the improved local density approximation (ILDA) in CTOM is adopted, which is also suitable to modify the nucleon interaction range in α -nucleus systems. To get better description of experimental data, the re-normalization factors ( N R , N I ) are introduced in α -nucleus scattering calculations, and the individual optimized ( N R , N I ) for all nuclei and energies are searched out under the guidance of χ 2 criterion. We systematically explore the energy dependence of N R and N I by considering the α elastic scattering from 12 C to 208 Pb at incident energies below 120 MeV / nucleon and a simple exponential function is extracted. With this global α -nucleus optical potential, a reasonable description of all available experimental data for α scattering from nuclei is achieved.

A consistent measurement of the inclusive single-neutron removal cross sections of $^{14,15,16}\mathrm{C}$ on a carbon target at around 240 MeV/nucleon has been performed at the External Target Facility, HIRFL-CSR, and compared with Glauber model predictions using shell-model spectroscopic strengths between the initial projectile ground state and configurations of bound core state $+$ valence neutron state as input. For the dependence of the spectroscopic factor reduction characterized by the ratio ${R}_{s}$ of the experimental over theoretical single-nucleon removal cross section on the bounding depth $\mathrm{\ensuremath{\Delta}}S$ of the removed nucleon established in single-nucleon removals with beam energies mainly over 80--120 MeV/nucleon, our measurement gives ${R}_{s}$ values that conform to the earlier ${R}_{s}\text{\ensuremath{-}}\mathrm{\ensuremath{\Delta}}S$ systematics, where the relatively higher incident beam energy facilitates the applicability of the eikonal and sudden approximation used in the Glauber model.

The reaction dynamics of exotic nuclei near the drip line is one of the main research topics of current interest. Elastic scattering is a useful probe for investigating the size and surface diffuseness of exotic nuclei. The development of rare isotope accelerators offers opportunities for such studies. To date, many relevant measurements have been performed at accelerators using the projectile fragmentation technique, while the measurements at accelerators using isotope separator on-line (ISOL) systems are still quite scarce. In this work, we present the first proof-of-principle experiment with a post-accelerated ISOL beam at the Beijing Radioactive Ion Beam Facility (BRIF) by measuring the angular distribution of elastic scattering for the stable nucleus $$^{23}$$ Na from the doubly magic nucleus $$^{40}$$ Ca at energies above the Coulomb barrier. The angular distribution measured by a silicon strip detector array in a scattering chamber using the ISOL beam at BRIF is in good agreement with that measured by the high-precision Q3D magnetic spectrograph using the non-ISOL beam at nearly the same energy. This work provides useful background for making BRIF a powerful tool for the investigation of the reaction dynamics of exotic nuclei.

An overall reduction factor (ORF) is introduced for studying the quenching of single-particle strengths through nucleon transfer reactions. The ORF includes contributions of all the probed bound states of the residual nucleus in a transfer reaction and permits a proper comparison with results of inclusive knockout reactions. A systematic analysis is made with 103 sets of angular distribution data of (p,d) reactions on 21 even–even targets with atomic mass numbers from 8 to 56 using the consistent three-body model reaction methodology proposed in Lee et al. (2006) [25]. The extracted ORFs are found to be nearly independent on the proton–neutron asymmetry, which is different from the systematics of inclusive knockout reactions but is consistent with the recent measurement of (d,t), (d,He3), (p,2p), and (p,pn) reactions on nitrogen and oxygen isotopes and ab initio calculations.

To study the quenching of single-particle strengths of carbon isotopes, a systematic analysis is performed for 9-12,14-20C, with single neutron knockout reactions on Be/C targets, within an energy range from approximately 43 to 2100 MeV/nucleon, using the Glauber model. Incident energies do not show any obvious effect on the resulting values across this wide energy range. The extracted quenching factors are found to be strongly dependent on the proton-neutron asymmetry, which is consistent with the recent analysis of knockout reactions but is inconsistent with the systematics of transfer and quasi-free knockout reactions.

A resonant state at 3.21-0.04+0.12MeV, located just above the one-neutron separation threshold, was observed for the first time in Be12 from the Be11(d,p)Be12 one-neutron transfer reaction in inverse kinematics. This state is assigned a spin-parity of 0- according to the systematics of the level scheme of the N=8 isotones and decay-width analysis. Gamow coupled-channel and Gamow shell-model calculations show the importance of the continuum coupling, which dramatically influences the excitation energy and ordering of low-lying states. Various exotic structures associated with cross-shell intruding configurations in Be12 and in its isotonic nucleus Li11 are comparably discussed.

Cluster aspects of the nuclear structure manifest themselves in, among many other types of nuclear reactions, the breakup reactions of weakly-bound nuclei and their couplings with the other reaction channels. In the present work we analyzed the breakup coupling effects to the elastic scattering angular distributions of $$^{11}$$ Be with a $$^{208}$$ Pb target at an incident energy of 140 MeV. Weighted mean local polarization potentials (WMLPPs), which mimic the dynamic polarization potentials (DPPs) induced by the breakup coupling effects to the elastic scattering channel, were obtained from continuum discretized coupled channel (CDCC) calculations. Suppression of the Coulomb-nuclear interference peaks (CNIPs) of the elastic scattering angular distributions is found to be caused by the destructive interference between the Coulomb and the Coulomb-distorted nuclear amplitude due to the WMLPPs. Comparisons between the WMLPPs and the theoretically calculated Coulomb dipole polarization potentials (CDPPs) suggest that the breakup coupling effect of the $$^{11}$$ Be+ $$^{208}$$ Pb system cannot be represented by the CDPPs alone.

With the development of radioactive beam facilities, studies concerning the shell evolution of unstable nuclei have recently gained prominence. Intruder components, particularly s-wave intrusion, in the low-lying states of light neutron-rich nuclei near N=8 are of importance in the study of shell evolution. The use of single-nucleon transfer reactions in inverse kinematics has been a sensitive tool that can be used to quantitatively investigate the single-particle orbital component of selectively populated states. The spin-parity, spectroscopic factor (or single-particle strength), and effective single-particle energy can all be extracted from such reactions. These observables are often useful to explain the nature of shell evolution, and to constrain, check, and test the parameters used in nuclear structure models. In this article, the experimental studies of the intruder components in low-lying states of neutron-rich nuclei of He, Li, Be, B, and C isotopes using various single-nucleon transfer reactions are reviewed. The focus is laid on the precise determination of the intruder s-wave strength in low-lying states.

A novel description of charge-exchange reactions at intermediate energies is developed, based on both phenomenological or microscopic eikonal phase-shift functions. The results obtained within this eikonal approach are in good agreement with the distorted-wave Born approximation calculations within the energy region where both approximations should be valid. They also compare well with the experimental data, even at relatively low energy domain. At higher energies, relativistic kinematics have also been added and shown to be relevant. Owing to the microscopic feature of the formulation, our theory also has the advantage that it can be applied to high energies where the phenomenological optical potentials are rarely available.

The $^{12}\mathrm{C}(\ensuremath{\alpha},\ensuremath{\gamma})^{16}\mathrm{O}$ reaction is one of the most crucial reactions in nuclear astrophysics. The $E2$ external capture to the $^{16}\mathrm{O}$ ground state (GS) has not been emphasized in previous analyses but may make a significant contribution to the $^{12}\mathrm{C}(\ensuremath{\alpha},\ensuremath{\gamma})^{16}\mathrm{O}$ cross section depending on the value of the GS asymptotic normalization coefficient (ANC). In the present work, we determine this ANC to be $337\ifmmode\pm\else\textpm\fi{}45\text{ }\text{ }{\mathrm{fm}}^{\ensuremath{-}1/2}$ through the $^{12}\mathrm{C}(^{11}\mathrm{B},^{7}\mathrm{Li})^{16}\mathrm{O}$ reaction using a high-precision magnetic spectrograph. This sheds light on the existing large discrepancy of more than 2 orders of magnitude between the previously reported ANC values. Based on the new ANC, we experimentally constrain the GS external capture and show that through interference with the high energy tail of the ${2}^{+}$ subthreshold state, a substantial enhancement in the GS ${S}_{E2}(300)$ factor can be obtained ($70\ifmmode\pm\else\textpm\fi{}7\text{ }\text{ }\mathrm{keV}\text{ }\mathrm{b}$) compared to that of a recent review (45 keV b), resulting in an increase of the total $S$ factor from 140 to 162 keV b, which is now in good agreement with the value obtained by reproducing supernova nucleosynthesis calculations with the solar-system abundances. This work emphasizes that the external capture contribution for the ground state transition cannot be neglected in future analyses of the $^{12}\mathrm{C}(\ensuremath{\alpha},\ensuremath{\gamma})^{16}\mathrm{O}$ reaction.

A puzzle has long existed for the α-cluster content in the near-threshold 7.54-MeV state of Be10. A new measurement was conducted to measure the cluster-decay partial width of this state using the reaction Be9(Be9,Be*10→α+He6)Be8 at 45-MeV beam energy. Special measures were taken to reduce the strong near-threshold background. The neutron-decay strength was also obtained based on the threefold coincident measurement. A cluster-decay branching ratio of (4.04±1.26)×10−4 is obtained, resulting in a reasonably large α-cluster spectroscopic factor. The present Rapid Communication confirms the formation of the σ-bond molecular rotational band headed by the 6.18-MeV state in Be10.

We review the Trojan horse method and its applications to resonant reactions in nuclear astrophysics.

Angular distributions of quasielastic scattering and breakup of the neutron-rich halo nucleus 11Be on a 208Pb target at an incident energy of 140 MeV (about 3.5 times the Coulomb barrier) were measured at HIRFL-RIBLL. A strong suppression of the Coulomb nuclear interference peak is observed in the measured quasielastic scattering angular distribution. The result demonstrates for the first time the persistence of the strong breakup coupling effect reported so far for reaction systems involving neutron-halo nuclei at this relatively high incident energy. The measured quasielastic scattering cross sections are satisfactorily reproduced by continuum discretized coupled channel (CDCC) calculations as well as by the XCDCC calculations where the deformation of the 10Be core is taken into account. The angular and energy distributions of the 10Be fragments could also be well reproduced considering elastic breakup (CDCC and XCDCC) plus nonelastic breakup contributions, with the latter evaluated with the model by Ichimura, Austern and Vincent [1]. The comparison of the 10Be energy distributions with simple kinematical estimates evidence the presence of a significant post-acceleration effect which, in the (X)CDCC frameworks, is accounted for by continuum-continuum couplings. National Key Research and Development Program of China (Grant No. 2018YFA0404403) National Natural Science Foundation of China (Grant No. 11775013, No. 11947203, No. 11575256, and No. U1632138) Youth Innovation Promotion Association CAS (No. 2020411) Ministerio de Ciencia, Innovación y Universidades FIS2017-88410-P European Union’s Horizon 2020 (Grant Agreement No. 654002)

The cross section for one-proton knockout from $^{16}\mathrm{C}$ with a large neutron-proton separation energy asymmetry on a carbon target has been measured at an intermediate beam energy of around 240 MeV/nucleon. The measured cross section is compared to the predictions based on the eikonal reaction model with shell-model structure inputs. The beam-energy dependence of the reduction on the extracted spectroscopic strength for strongly bound nucleon removal is derived from combining the existing intermediate-energy data with the present measurement. The deduced reduction factor ${R}_{s}$, defined as the ratio of the measured and theoretical cross sections, for the strongly bound nucleon removal at around 240 MeV/nucleon is consistent with the systematics observed from knockout reactions induced by light nuclear targets at intermediate energies of around 80 MeV/nucleon.

We present the first experimental determination on the spectroscopic amplitudes (SAs) for the α-cluster in the B 11 ground state via the Li 7 ( Li 6 , d ) 11 B reaction using a high-precision magnetic spectrograph. This is believed to have a strong effect on the studies of α-induced reactions which are crucial in nuclear astrophysics. It is found that the previous SAs of B 11 from shell model calculations cause overestimations of up to 23% for the C 12 ( α , γ ) 16 O S E 2 ( 300 ) factor and up to 34% for the C 13 ( α , n ) 16 O S ( 190 ) factor with respect to the results from the present experimentally determined SAs. Due to the importance of these two reactions, for example the uncertainty in the C 12 ( α , γ ) 16 O cross section at E c.m. = 300 keV is required to be better than 10% by stellar modeling, the new S-factors could result in a potential influence on the astrophysical network calculations.

A new 11Be( d , p )12Be transfer reaction experiment was carried out in inverse kinematics at 26.9A MeV, with special efforts devoted to the determination of the deuteron target thickness and of the required optical potentials from the present elastic scattering data. In addition a direct measurement of the cross section for the 0 2 + state was realized by applying an isomer-tagging technique. The s-wave spectroscopic factors of 0.20 − 0.04 + 0.03 and 0.41 − 0.11 + 0.11 were extracted for the 0 1 + and 0 2 + states, respectively, in 12Be. Using the ratio of these spectroscopic factors, together with the previously reported results for the p-wave components, the single-particle component intensities in the bound 0 + states of 12Be were deduced, allowing a direct comparison with the theoretical predictions. It is evidenced that the ground-state configuration of 12Be is dominated by the d-wave intruder, exhibiting a dramatic evolution of the intruding mechanism from 11Be to 12Be, with a persistence of the N = 8 magic number broken.

Carbon-carbon burning plays an important role in many stellar environments. Recently, Tumino et al. [Nature (London) 557, 687 (2018)] reported a sharp rise of the astrophysical $S$ factor for carbon-carbon fusion determined using the indirect Trojan horse method. We demonstrate that the rise at low energies seen in the aforementioned work is an artifact of using an invalid plane-wave approximation that neglects the Coulomb interactions between charged particles. Our analysis shows that such a rise disappears if the Coulomb (or Coulomb-nuclear) interactions in the initial and final states are included.

The $^{12}\mathrm{C}(\ensuremath{\alpha},\ensuremath{\gamma})^{16}\mathrm{O}$ reaction plays a key role in the evolution of stars with masses of $Mg0.55\phantom{\rule{0.16em}{0ex}}{M}_{\ensuremath{\bigodot}}$. The cross-section of the $^{12}\mathrm{C}(\ensuremath{\alpha},\ensuremath{\gamma})^{16}\mathrm{O}$ reaction within the Gamow window (${E}_{\text{c.m.}}=300\phantom{\rule{0.16em}{0ex}}\mathrm{keV}, {T}_{9}=0.2$) is extremely small (about ${10}^{\ensuremath{-}17}$ barn), which makes the direct measurement in a ground-based laboratory with existing techniques unfeasible. Up until now, the cross-sections at lower energies can only be extrapolated from the data at higher energies. However, two subthreshold resonances, located at ${E}_{x}=7.117\phantom{\rule{0.16em}{0ex}}\mathrm{MeV}$ and ${E}_{x}=6.917\phantom{\rule{0.16em}{0ex}}\mathrm{MeV}$, make this extrapolation more complicated. In this work, the 6.917 MeV subthreshold resonance in the $^{12}\mathrm{C}(\ensuremath{\alpha},\ensuremath{\gamma})^{16}\mathrm{O}$ reaction was investigated via the $^{12}\mathrm{C}(^{11}\mathrm{B},^{7}\mathrm{Li})^{16}\mathrm{O}$ reaction. The experiment was performed using the Q3D magnetic spectrograph at the HI-13 tandem accelerator. We measured the angular distribution of the $^{12}\mathrm{C}(^{11}\mathrm{B},^{7}\mathrm{Li})^{16}\mathrm{O}$ transfer reaction leading to the 6.917 MeV state. Based on the finite-range distorted wave Born approximation (FRDWBA) and coupled-reaction-channel (CRC) analysis, we derived the asymptotic normalization coefficient (ANC) of the 6.917 MeV level in $^{16}\mathrm{O}$ to be ($1.10\ifmmode\pm\else\textpm\fi{}0.29$) $\ifmmode\times\else\texttimes\fi{}{10}^{10}\phantom{\rule{0.16em}{0ex}}{\mathrm{fm}}^{\ensuremath{-}1}$, with which the reduced $\ensuremath{\alpha}$ width was computed to be $18.0\ifmmode\pm\else\textpm\fi{}4.7\phantom{\rule{0.16em}{0ex}}\mathrm{keV}$ at the channel radius of 6.5 fm. Finally, we calculated the astrophysical ${S}_{E2}(300)$ factor of the ground-state transitions to be 46.2 $\ifmmode\pm\else\textpm\fi{}$ 7.7 keV b. The result for the astrophysical ${S}_{E2}(300)$ factor confirms the values obtained in various direct and indirect measurements and presents an independent examination of the most important data in nuclear astrophysics.

The cross sections for two-neutron removal from $^{15,16}\mathrm{C}$ on a carbon target have been measured at around 240 MeV/nucleon. The measured cross section for $^{15}\mathrm{C}$ is smaller than for $^{16}\mathrm{C}$. The trends of the cross sections for $^{15,16}\mathrm{C}$ are inconsistent with the previously reported experimental data, but in agreement with the theoretical predictions based on eikonal-model calculations. Based on the present results of $^{15,16}\mathrm{C}$ combined with the available experimental data on $^{17--20}\mathrm{C}$, an odd-even staggering of the two-neutron removal cross sections along the neutron-rich carbon isotopic chain from $^{15}\mathrm{C}$ to $^{20}\mathrm{C}$ is observed, and this feature is well reproduced by the theoretical calculations.

A detailed feasibility study on deducing the high-lying single particle components (HLSPCs), which are important but used to be ignored, in the ground and low-lying excited states of even-even light nuclei is performed by analyses of $(p,d)$ reactions with $^{12}\mathrm{C}$, $^{24}\mathrm{Mg}$, $^{28}\mathrm{Si}$, and $^{40}\mathrm{Ca}$ targets at 51.93 MeV. Coupled reaction channel analyses have been made for $(p,d)$ transitions to the $j$-forbidden excited states in $^{11}\mathrm{C}$ (${\frac{5}{2}}^{\ensuremath{-}}$; 4.32 MeV), $^{23}\mathrm{Mg}$ (${\frac{7}{2}}^{+}$; 2.05 MeV), $^{27}\mathrm{Si}$ (${\frac{7}{2}}^{+}$; 2.16 MeV), and $^{39}\mathrm{Ca}$ (${\frac{9}{2}}^{\ensuremath{-}}$; 3.64 MeV), including the major allowed transition components together with direct components of HLSPCs. Spectroscopic amplitudes of the HLSPCs are deduced by fitting the angular distributions of the ground and the $j$-forbidden excited states simultaneously. The present analysis demonstrates for the first time that information about HLSPCs in atomic nuclei can be obtained from analysis of $(p,d)$ reactions.

The angular distribution of 12 C + 12 C scattering at an incident energy of 100 A MeV has been measured. The elastic and inelastic scatterings in 12 C to the excitation energies of up to ∼ 45 MeV were measured simultaneously for the first time with the high-resolution Grand Raiden spectrometer at the Research Center for Nuclear Physics (RCNP). The angular distributions of the elastic scattering to the ground state ( 0 1 + ) and inelastic scattering to the 4.44 MeV ( 2 1 + ) excited state were precisely obtained in the angular range of 1.0°–7.5° with a step of 0.1°. Additionally, the angular distribution was obtained for the sum of the cross sections for excitation energies above the 4.44 MeV state up to 11 MeV, which includes the 7.65 MeV ( 0 2 + ), 9.64 MeV ( 3 1 − ), and 10.30 MeV ( 2 2 + ) states, in addition to probably the simultaneous excitation of the 4.44 MeV state in the projectile and the target nuclei. Those combined data provide a means to study the effects of channel coupling on the elastic cross section. The observed angular distributions are compared with theoretical calculations based on three double-folding models with complex G-matrix interactions, the CEG07b, MPa, and ESC models. The importance of three-body repulsive forces included in the CEG07b and MPa models will be discussed.

Elastic scattering of 10Be on a 208Pb target was measured at = 127 MeV, which corresponds to three times the Coulomb barrier. The secondary 10Be beam was produced at the Radioactive Ion Beam Line in Lanzhou of the Heavy-Ion Research Facility in Lanzhou. The angular distribution of elastic scattering in the 10Be + 208Pb system shows a typical Fresnel diffraction peak. Optical model analysis of the angular distribution was performed using the Woods-Saxon, double-folding and global potentials. With the global potential, different density distributions were used. The results indicate that different density distributions for the projectile induce distinct effects in the angular distribution.

In order to describe charge exchange reactions at intermediate energies, we implemented as a first step the formulation of the normal eikonal approach. The calculated differential cross-sections based on this approach deviated significantly from the conventional DWBA calculations for CE reactions at 140 MeV/nucleon. Thereafter, improvements were made in the application of the eikonal approximation so as to keep a strict three-dimensional form factor. The results obtained with the improved eikonal approach are in good agreement with the DWBA calculations and with the experimental data. Since the improved eikonal approach can be formulated in a microscopic way, it is easy to apply to CE reactions at higher energies, where the phenomenological DWBA is a priori difficult to use due to the lack, in most cases, of the required phenomenological potentials.

This study aims to analyze the differential cross sections (DCSs) of elastic scattering and total reaction cross sections (TRCSs) of the loosely-bound deuteron projectile impinging on 1p-shell nuclei, such as 9Be, 12C, and 16O, at incident energies ranging between 10.6 and 171 MeV using the continuum discretized coupled channel (CDCC) method. By fitting the experimental data for the DCSs and TRCSs, energy-dependent renormalization factors for the real and imaginary parts of the nucleon-nucleus optical-model potentials deduced from the studies proposed by Koning and Delaroche (KD02) and by Watson, Singh, and Segel (WSS), are obtained. It is found that with the WSS potential, which was obtained specifically for 1 p-shell nuclei, the CDCC calculations can simultaneously reproduce both the DCSs and the TRCSs. The results show that it is important to choose appropriate optical potentials to describe deuteron-induced reactions.

The inelastic excitations and cluster decay of $^{13}$C have been measured using the reaction, $^9$Be($^{13}$C,$^{13}$C* $\rightarrow$ $^9$Be + $\alpha$ )$^9$Be. We observe strong excitation to the 14.3-MeV (1/2$^-$) resonant state from the cluster-decay channel, leading to an enhanced monopole matrix element of (6.3 $\pm$ 0.6) fm$^2$. This large cluster-related monopole strength is a clear indication of the cluster-structure domination of this state and is consistent with the recent prediction of the orthogonality condition model (OCM). It would be interesting to further explore the three-center molecular rotational band that is initiated from the observed band-head.

Calculations of the direct radiative capture reactions are made for the $^{48}\mathrm{Ca}(n,\ensuremath{\gamma})^{49}\mathrm{Ca}$, $^{7}\mathrm{Li}(n,\ensuremath{\gamma})^{8}\mathrm{Li}$, and $^{12}\mathrm{C}(p,\ensuremath{\gamma})^{13}\mathrm{N}$ reactions with the Perey-Buck-type nonlocal potentials using a potential model. Our results reproduce the experimental data reasonably well. From comparisons to results obtained by using local potentials, it is found that the cross sections of direct capture reactions may change by around 25% due to the nonlocality of nuclear potentials.

The 7Be(p, γ)8B reaction plays a central role not only in the evaluation of solar neutrino fluxes but also in the evolution of the first stars. Study of this reaction requires the asymptotic normalization coefficient (ANC) for the virtual decay 8B g.s. → 7Be + p. By using the charge symmetry relation, we obtain this proton ANC with the single neutron ANC of 8Li g.s. →7Li + n, which is determined with the distorted wave Born approximation (DWBA) and adiabatic distorted wave approximation (ADWA) analysis of the 7Li(d, p)8Li angular distribution. The astrophysical S-factors and reaction rates of the direct capture process in the 7Be(p, γ)8B reaction are further deduced at energies of astrophysical relevance. The astrophysical S-factor at zero energy for direct capture, S 17(0), is derived to be (19.9 ± 3.5) eV b in good agreement with the most recent recommended value. The contributions of the 1+ and 3+ resonances to the S-factor and reaction rate are also evaluated. The present result demonstrates that the direct capture dominates the 7Be(p, γ)8B reaction in the whole temperature range. This work provides an independent examination to the current results of the 7Be(p, γ)8B reaction.

Several elastic scattering angular distributions of $^{12}$C from target nuclei of $A\geqslant$ 39 are analyzed to extract the Woods-Saxon potential parameters with the fixed imaginary potential and Coulomb radius parameters. Using the best fitted diffuseness parameters, the correlations of the real part parameters with $A_1^{1/3}+A_2^{1/3}$ and incident energy are revealed, and the systematic Woods-Saxon potential parameters are presented for nucleus-nucleus interaction. The proposed potential parameters can reproduce not only the elastic scattering angular distributions induced by $^{12}$C, but also many elastic scattering angular distributions induced by the projectiles other than $^{12}$C, thus providing important inputs for the study of nuclear reactions of heavy-ion systems.

The angular distributions of differential cross sections of $^{12}\mathrm{C}+^{12}\mathrm{C}$ elastic and inelastic scattering populating the ground and excited states in $^{12}\mathrm{C}$ up to 15 MeV excitation energy are precisely measured for the first time at an incident energy of $100A$ MeV to study the effect of repulsive three-body forces. Using the high-resolution spectrometer Grand Raiden at the Research Center for Nuclear Physics (RCNP), Osaka University, we have obtained the differential cross sections for the ground state (${0}_{1}^{+}$) and 4.44 MeV (${2}_{1}^{+}$) excited state, as well as the summed differential cross sections for the states between 4.44 and 15 MeV in the angular range of $1.{0}^{\ensuremath{\circ}}--7.{5}^{\ensuremath{\circ}}$. The results are compared with microscopic coupled-channel calculations. The potential between the colliding nuclei is determined by the double folding method with three different complex $G$-matrix interactions, the ESC, CEG07b, and MPa interactions. The CEG07b and MPa interactions, which include repulsive three-body forces, describe the data well, whereas the ESC interaction, which does not include repulsive three-body forces, fails to reproduce the data. The results provide evidence of repulsive three-body forces in $^{12}\mathrm{C}$ and demonstrate the possible sensitivity of elastic scattering to three-body forces.

The elastic scattering and breakup reactions of the halo nucleus $^{11}\mathrm{Be}$ on deuterons at an incident energy of $26.9A$ MeV are reported for the first time. Special attention has been paid to the determination and subtraction of the proton contaminations in the deuterated polyethylene ${({\mathrm{CD}}_{2})}_{n}$ target (where ${\mathrm{D}}_{2}$ denotes $^{2}\mathrm{H}_{2}$). The cross sections for elastic scattering are analyzed with the systematic optical potentials of Daehnick et al. and DA1p, as well as with single-folding potentials, derived from the Jeukenne-Lejeune-Mahaux effective nucleon-nucleon interaction. An extended version of the continuum-discretized coupled-channels (XCDCC) formalism, including dynamic core excitation (DCX) effects, is applied to analyze the elastic scattering and breakup data. Comparisons of the full XCDCC calculation with that omitting DCX effects indicate that the core excitation plays a remarkable role in reproducing breakup reactions of $^{11}\mathrm{Be}+d$.

We have measured the 16O(p, d) reaction using 198-, 295- and 392-MeV proton beams to search for a direct evidence on an effect of the tensor interactions in light nucleus. Differential cross sections of the one-neutron transfer reaction populating the ground states and several low-lying excited states in 15O were measured. Comparing the ratios of the cross sections for each excited state to the one for the ground state over a wide range of momentum transfer, we found a marked enhancement of the ratio for the positive-parity state(s). The observation is consistent with large components of high-momentum neutrons in the initial ground-state configurations due to the tensor interactions.

Experimental data show that the elastic scattering cross sections of the neutron-rich nucleus $^{11}\mathrm{Be}$ are greatly reduced by the coupling effects from the breakup channels, while those of the proton-rich nucleus $^{8}\mathrm{B}$ are not. Such difference is found to persist in results of systematic calculations of $^{8}\mathrm{B}$ elastic scattering from $^{208}\mathrm{Pb}$ at 60 and 170.3 MeV and from $^{64}\mathrm{Zn}$ at 32 and 86 MeV, and $^{11}\mathrm{Be}$ elastic scattering from $^{208}\mathrm{Pb}$ at 55 and 143 MeV and from $^{64}\mathrm{Zn}$ at 29 and 66 MeV with the continuum-discretized coupled channel (CDCC) method. The Coulomb and centrifugal barriers experienced by the valence proton in the ground state of $^{8}\mathrm{B}$, which do not exist for the valence neutron in the ground state of $^{11}\mathrm{Be}$, are found to be the reason for such differences in the angular distributions of elastic scattering cross sections of these two weakly bound nuclei.

A set of global optical potential parameters, DA1p, for deuterons with the $1p$-shell nuclei is obtained by simultaneously fitting 67 sets of experimental data of deuteron elastic scattering from $^{6}\mathrm{Li}$, $^{9}\mathrm{Be}$, $^{10}\mathrm{B}$, $^{11}\mathrm{B}$, $^{12}\mathrm{C}$, $^{13}\mathrm{C}$, $^{14}\mathrm{N}$, $^{16}\mathrm{O}$, and $^{18}\mathrm{O}$ with incident energies between 5.25 and 170 MeV. DA1p improves the description of the deuteron elastic scattering from the $1p$-shell nuclei with respect to the existing systematic deuteron potentials and can give satisfactory reproduction of the experimental data with radiative nuclei such as $^{9}\mathrm{Li}$, $^{10}\mathrm{Be}$, $^{14}\mathrm{C}$, and $^{14}\mathrm{O}$.

The elastic scattering and breakup of the halo nucleus $^{11}\mathrm{Be}$ on protons at an incident energy of $26.9A$ MeV have been measured. The $^{11}\mathrm{Be}+p$ elastic scattering cross sections at various energies, including the present one, are systematically analyzed with the Chapel Hill 89 (CH89) and Koning-Delaroche (KD) global optical model potentials (OMPs), and the corresponding normalization factors are obtained. An extended version of the continuum-discretized coupled-channels (XCDCC) formalism, including dynamic core excitation effects, is applied to analyze the elastic scattering and breakup data. It is found that the core excitation plays a moderate role in the elastic scattering and breakup reaction of the halo nucleus $^{11}\mathrm{Be}$, being consistent with previous results at higher energies.

The unbound O12 nucleus was studied via the two-neutron transfer (p,t) reaction in inverse kinematics using a radioactive O14 beam at 51 MeV/u. Excitation energy spectra and differential cross sections were deduced by the missing mass method using MUST2 telescopes. We achieved much higher statistics compared to the previous experiments of O12, which allowed accurate determination of resonance energy and unambiguous spin and parity assignment. The O12 resonance previously reported using the same reaction was confirmed at an excitation energy of 1.62±0.03(stat.)±0.10(syst.). MeV and assigned spin and parity of 0+ from a distorted-wave Born approximation analysis of the differential cross sections. Mirror symmetry of O12 with respect to its neutron-rich partner Be12 is discussed from the energy difference of the second 0+ states. In addition, from systematics of known 0+ states, a distinct correlation is revealed between the mirror energy difference and the binding energy after carrying out a scaling with the mass and the charge. We show that the mirror energy difference of the observed 0+ state of O12 is highly deviated from the systematic trend of deeply bound nuclei and in line with the scaling relation found for weakly bound nuclei with a substantial 2s1/2 component. The importance of the scaling of mirror asymmetry is discussed in the context of ab initio calculations near the drip lines and universality of few-body quantum systems.

Continuum discretised coupled-channels (CDCC) method with a 10Be(0+) + n two-body cluster model is applied to systematically analyze the elastic scattering of the halo nucleus 11Be from the proton target at various incident energies below 100 MeV/nucleon. Using the renormalized 10Be-p potential deduced from the 10Be + p elastic scattering data, the differential cross sections of 11Be + p scattering are well reproduced by the CDCC calculations without any further adjustment parameters, demonstrating the applicability of this approach for describing the scattering of exotic nuclei based on the scattering of the less exotic core nuclei.

We report for the first time the discrimination of the core fragment knockout and valence nucleon knockout reaction mechanisms at medium energy range, by the use of the recoil proton tagging technique. Intense 8He beams at 82.3 MeV/u were supplied by the RIPS beam line at RIKEN, and impinged on both hydrogen and carbon targets. Recoil protons were detected in coincidence with the forward moving core fragments and neutrons. The core fragment knockout mechanism is identified through the polar angle correlation and checked by various kinematics relations. This mechanism may be used to extract the cluster structure information of unstable nuclei. On the other hand, with the selection of the tagged valence nucleon knockout mechanism, a narrower peak of 7He ground state is obtained. The extracted neutron spectroscopic factor S n = 0.512 ( 18 ) is relatively smaller than the no-tagged one, and is in good agreement with the prediction of ab initio Greenʼs function Monte Carlo calculations.

A new 11 Be(p,d) transfer reaction experiment is performed in inverse kinematics with a radioactive 11 Be beam at 26.9A MeV. Three low-lying states, namely the 0 + ground state, the 2 + state at Ex = 3.37 MeV, and the multiplet at around 6 MeV in 10 Be, are populated by this one-neutron transfer reaction. These three states in 10 Be are clearly discriminated from the Q-value spectrum, which is rebuilt from energies and angles of the recoil deuterons in coincidence with 10 Be. A spectroscopic factor for each state is extracted by comparing the experimental differential cross sections to the theoretical calculation results using the finite range adiabatic distorted wave approximation method with different global nucleon-nucleus potentials. It is found that the newly extracted spectroscopic factors for the 0 + and 2 + states are consistent with the previous ones, but the factor for the multiplet is smaller than the value in the reference, and the possible reason is discussed.

The low-lying spectra of 8He and 10He nuclei were studied in the 3H(6He, p)8He and 3H(8He, p)10He transfer reactions. The 0+ ground state (g.s.) of 8He and excited states, 2+ at 3.6–3.9 MeV and (1+) at 5.3–5.5 MeV, were populated with cross sections of 200, 100–250, and 90–125 μb/sr, respectively. Some evidence for a 8He state at about 7.5 MeV was obtained. We discuss a possible nature of the nearthreshold anomaly above 2.14 MeV in 8He and relate it to the population of a 1− continuum (soft dipole excitation) with a peak value at about 3 MeV. The lowest energy group of events in the 10He spectrum was observed at ∼ 3 MeV with a cross section of ∼ 140 μb/sr. We argue that this result is consistent with the previously reported observation of 10He providing the new 10He g.s. position at about 3 MeV

Intermediate-energy Coulomb excitation of $^{32}\mathrm{Mg}$ using in-beam $\ensuremath{\gamma}$-ray spectroscopy with a relatively thick lead target was studied at a beam energy of 195 MeV/nucleon at the RIKEN Radioactive Isotope Beam Factory (RIBF). The angular distribution of the inelastic scattering was analyzed with distorted-wave calculations taking into account both the Coulomb and the nuclear excitation contributions. A $B(E2)$ value of 432(51) ${e}^{2}\phantom{\rule{0.16em}{0ex}}{\mathrm{fm}}^{4}$ was extracted, which agrees with most of the previously reported results obtained at several tens of MeV/nucleon. Our investigation demonstrates that the electromagnetic properties of exotic nuclei can be studied with Coulomb excitation at beam energies of a few hundreds of MeV/nucleon, where a thicker target can be used to increase the excitation yields.

We discuss recent developments in indirect methods used in nuclear astrophysics to determine the capture cross sections and subsequent rates of various stellar burning processes, when it is difficult to perform the corresponding direct measurements. We discuss in brief, the basic concepts of Asymptotic Normalization Coefficients, the Trojan Horse Method, the Coulomb Dissociation Method, (d,p), and charge-exchange reactions., Comment: 9 pages, three figures, Proceedings of the Eighth European Summer school on Experimental Nuclear Astrophysics, 2015, edited by C. Spitaleri, L. Lamia and R.G. Pizzone

Sensitivity of the direct nuclear reaction to the exotic structure of the unstable nuclei is outlined. The transfer reaction induced by 6 He on a 9 Be target at 25 MeV/u is described. The theoretical analysis using CRC model supports the di-neutron configuration of the two valence neutrons in 6 He . Preliminary calculation for 17 Ne were introduced which indicates the advantage of using transfer reaction to clarify the s-wave or d-wave configuration of the valence protons.