Charge-changing cross sections ${\sigma }_{\mathrm{CC}}$ for ${}^{42\text{–}51}\mathrm{Ca}$ on a carbon target at around 280 MeV/nucleon have been measured. Though the existing point-proton radii $r_{\mathrm{p}}$ of Ca isotopes increase as the neutron number increases, the measured ${\sigma }_{\mathrm{CC}}$ data show a significant decrease, which is against the expectation from a simple Glauber-like model. We found that this observed phenomenon could be attributed to the charged-particle evaporation effect induced by the neutron-removal reaction. By taking the evaporation effect into account, various ${\sigma }_{\mathrm{CC}}$ data sets for nuclides from C to Fe isotopes on ${}^{12}\mathrm{C}$ measured at around 280 MeV/nucleon are reproduced with a standard deviation of 1.6%. It is also clarified that this evaporation effect becomes negligibly small in the neutron-rich region. The evaluated relation between ${\sigma }_{\mathrm{CC}}$ and $r_{\mathrm{p}}$ using the current model indicates that ${\sigma }_{\mathrm{CC}}$ data for neutron-rich Ca isotopes ($A\ge 51$) are highly sensitive to $r_{\mathrm{p}}$. This high sensitivity potentially allows one to determine the $r_{\mathrm{p}}$ of very neutron-rich nuclei.

The fragment separator FRS has been used for the first time to measure the $(n,p)$- and $(p,n)$-type isobaric charge-exchange cross sections of stable ${}^{112,124}\mathrm{Sn}$ isotopes accelerated at $1A$ GeV with an uncertainty of $3\%$ and to separate quasielastic and inelastic components in the missing-energy spectra of the ejectiles. The inelastic contribution can be associated to the excitation of isobar $\mathrm{\Delta }$(1232) resonances and to the pion emission in $s$ wave, in both the target and projectile nuclei, while the quasielastic contribution is associated with the nuclear spin-isospin response of nucleon-hole excitations. The data lead to interesting results, where we observe a clear quenching of the quasielastic component, and their comparisons to theoretical calculations demonstrate that the baryonic resonances can be excited in the target and projectile nuclei. To go further in this investigation, we propose to study the excitation of baryonic resonances, taking advantage of the combination of high-resolving power magnetic spectrometers with the Wide Angle Shower Apparatus (WASA) calorimeter. These new measurements will allow us to determine the momenta of the ejectiles and pions emitted in coincidence after the single isobaric charge-exchange collisions, providing us unique opportunities to study the evolution of the baryonic resonance dynamics with the neutron-proton asymmetry through the use of exotic radioactive ion beams.

In this study, we analyzed how the incident neutron current is affected by the pairing effect in neutron-nucleus scattering described within the framework of Hartree-Fock-Bogoliubov theory by performing numerical calculations in terms of current, vorticity, and circulation of the incident neutron current. We found that the pairing effect on the incident neutron flux is completely different between particle-type and hole-type quasiparticle resonances. In the case of h-type quasiparticle resonance, the pairing acts to prevent the neutron flux from entering the nucleus, reducing circulation. In the case of p-type quasiparticle resonance, pairing acts to reduce circulation at energies lower than the resonance energy, but, at energies higher than the resonance energy, the effect of pairing on the neutron flux is reversed and, conversely, circulation is increased. These properties are consistent with the approximate expression for the vorticity characteristics at p-type and h-type resonances, implying that the vorticity appearing near p-type resonances due to the pair-correlation effect is inversely proportional to the resonance width (proportional to the resonance lifetime). In contrast, at h-type resonances, the pair-correlation effect has the effect of canceling out the vortex created by MF scattering and is independent of the resonance width.

Herein, a study of the correlation between nuclear temperature and symmetry energy is presented for heavy ion collisions at intermediate energies via the isospin-dependent quantum molecular-dynamics model. It is found that different symmetry energy parameters change the density and kinetic energy distribution of the hot nuclei. More importantly, nuclear temperatures that are based on kinetic energy properties can be used to study symmetry energy information.

Background: The $\alpha$-decay phenomenon has been studied for more than a century. Its mechanism is simply explained by two factors: the $\alpha$ formation probability and the penetration process through the potential barrier.

Purpose: As an alternative to the $\alpha$-decay lifetime measurement, we propose the proton-induced $\alpha$ knockout reaction, $(p,p\alpha )$, as a new probe for the surface $\alpha$ formation probability of $\alpha$-decay nuclei.

Method: The ${}^{210,212}\mathrm{Po}(p,p\alpha ){}^{206,208}\mathrm{Pb}$ reaction is described by the distorted-wave impulse approximation framework.

Results: It is shown that the ${}^{212}\mathrm{Po}/{}^{210}\mathrm{Po}$ ratio of the $\alpha$ knockout cross sections agrees with that of the surface $\alpha$ formation probabilities determined by lifetime measurements.

Conclusions: It was confirmed that the $(p,p\alpha )$ reaction cross sections correspond to the $\alpha$ formation probability of the nuclear surface. The result implies that the $(p,p\alpha )$ cross section is a direct probe for the surface $\alpha$ formation probability, which is an essential quantity for complete understanding of the $\alpha$-decay phenomenon.

The elastic scattering, first $2^{+}$ and $3^{-}$ target inelastic excitation and one neutron pickup angular distributions for the ${}^6\mathrm{Li}+{}^{120}\mathrm{Sn}$ reaction have been measured for three bombarding energies (19, 24, and 27 MeV). Data have been analyzed through coupled-channel calculations and continuum-discretized coupled-channel calculations extended to include target excitation. In general, both theoretical models give a reasonable description of the data. For the elastic and inelastic angular distributions taken at $E_{\mathrm{lab}}=24$ and 27 MeV, the continuum-discretized coupled-channel results are slightly better in comparison to the coupled-channel predictions. For the elastic and inelastic angular distributions measured at $E_{\mathrm{lab}}=19$ MeV, the effect of the break-up channel seems to be quite important. At this energy, the elastic scattering data can be well explained by coupled channel calculations in which a strong absorptive optical imaginary potential is considered. In particular, the continuum-discretized coupled-channel theoretical results provided the best description of the $3^{-}$ excitation data at 19 MeV.

Nuclei in the ${}^{135}\mathrm{I}$ region have been identified as being a possible bottleneck for the $i$ process. Here we present an indirect measurement for the Maxwellian-averaged cross section of ${}^{126}\mathrm{Sb}(n,\gamma )$. The nuclear level density and the $\gamma$-ray strength function of ${}^{127}\mathrm{Sb}$ have been extracted from ${}^{124}\mathrm{Sn}(\alpha ,p\gamma ){}^{127}\mathrm{Sb}$ data using the Oslo method. The level density in the low-excitation-energy region agrees well with known discrete levels, and the higher-excitation-energy region follows an exponential curve compatible with the constant-temperature model. The strength function between $E_{\gamma }\approx 1.5–8.0$ MeV presents several features, such as an upbend and a possibly double-peaked pygmy-like structure. None of the theoretical models included in the nuclear reaction code talys seem to reproduce the experimental data. The Maxwellian-averaged cross section for the ${}^{126}\mathrm{Sb}(n,\gamma ){}^{127}\mathrm{Sb}$ reaction has been experimentally constrained by using our level-density and strength-function data as input to talys. We observe a good agreement with the jina reaclib, tendl, and bruslib libraries, while the endf/b-viii.0 library predicts a significantly higher rate than our results.

The wobbling motion in even-even nuclei is investigated by means of a collective Hamiltonian constructed from a semiclassical treatment applied to a triaxial rotor with a rigidly aligned pair of quasiparticles. The limits of distinct wobbling regimes are discussed in connection to the dynamic evolution of the wobbling excitations and corresponding electromagnetic properties. Model calculations are performed for the description of transverse wobbling bands in ${}^{130}\mathrm{Ba}, {}^{134}\mathrm{Ce}$, and ${}^{136,138}\mathrm{Nd}$ nuclei.

Fission fragment mass and total kinetic energy (TKE) distributions were measured for ${}^{12}\mathrm{C}+{}^{175}\mathrm{Lu}$ system at excitation energies down to 16.7 MeV above the saddle point. The overall mass and TKE distributions could be fitted with single Gaussian functions. The observed width of the mass and TKE distributions agree well with the systematics based on liquid drop (LD) behavior. The average TKE also shows parabolic dependence on fragment mass, as expected from LD behavior. Small contributions due to microscopic corrections from $Z\approx 38$ and 45 shells can be extracted, if the widths of the LD component are fixed from systematics. Contrary to the theoretical predictions of substantial contributions from microscopic corrections, dominance of liquid drop behavior was observed.

Higher-order cumulants of the distributions of conserved charges, such as net-baryon number, are sensitive to the quantum chromodynamics (QCD) phase transition and the QCD critical point. We calculate the cumulants and correlation functions of proton, antiproton, and net-proton multiplicity distributions in $\mathrm{Au}+\mathrm{Au}$ collisions at $\sqrt{s_{NN}}=7.7$ GeV using a multiphase transport model (AMPT). The AMPT model can basically describe the trends of cumulants, cumulant ratios, (normalized) correlation functions of the proton and net-proton measured by the STAR experiment. The multiproton (baryon) correlations in the AMPT model are consistent with the expectation from baryon number conservation. We demonstrate that multiproton (baryon) correlations suffer the dynamical evolution of heavy-ion collisions. Our results provide a baseline for searching for the possible critical behaviors at the critical end point in relativistic heavy-ion collisions.

We propose a novel idea to construct an effective interaction under energy-density-functional (EDF) theories which is adaptive to the enlargement of the model space. Guided by effective field theory principles, iterations of interactions as well as enlargements of the model space through particle-hole excitations are carried out for infinite nuclear matter and selected closed-shell nuclei (${}^4\mathrm{He}, {}^{16}\mathrm{O}, {}^{40}\mathrm{Ca}, {}^{56}\mathrm{Ni}$, and ${}^{100}\mathrm{Sn}$) up to next-to-leading order. Our approach provides a new way for handling the nuclear matter and finite nuclei within the same scheme, with advantages from both EDF and ab initio approaches.

For the ${}^{48}\mathrm{Ca}$ and Ra/actinide-based complete fusion reactions, the excitation functions for the production of isotopes of superheavy nuclei with charge numbers 108–116 are calculated and compared to the available experimental data. The calculated production cross sections clearly indicate the border nucleus Ds between the island of stability of superheavy nuclei and the mainland with a relatively large number of neutrons.

Angular distributions of the differential cross section for elastic scattering and ${}^6\mathrm{Li}\to \alpha +d$ resonant breakup in the ${}^{10}\mathrm{B}+{}^6\mathrm{Li}$ system were measured in inverse kinematics with a 51-MeV ${}^{10}\mathrm{B}$ beam. A comparison with existing data for the ${}^{10}\mathrm{B}+{}^7\mathrm{Li}$ system at the same incident ${}^{10}\mathrm{B}$ energy revealed an important difference in the backward angle elastic scattering, with that for ${}^{10}\mathrm{B}+{}^6\mathrm{Li}$ being significantly larger in magnitude. A series of coupled channel and coupled discretized continuum channel calculations investigated the influence of ${}^{10}\mathrm{B}$ and ${}^7\mathrm{Li}$ ground state reorientation and breakup couplings on the elastic scattering. Elastic transfer of a ${}^4\mathrm{He}$ and ${}^3\mathrm{He}$ cluster between the ${}^6\mathrm{Li}$ and ${}^7\mathrm{Li}$ cores, respectively, was also investigated. Although a conclusive explanation of the observed difference in the backward angle elastic scattering between the two systems was not obtained, the elastic transfer mechanism could be definitively ruled out as a significant factor and there were indications that a difference in the effect of the breakup coupling may play a role even in these light systems. The ground state reorientation coupling in ${}^7\mathrm{Li}$, while exhibiting an interesting interference effect with the ${}^{10}\mathrm{B}$ ground state reorientation, was also found to make a negligible contribution to the difference in backward angle elastic scattering.

The spectroscopy of ${}^{71}\mathrm{Ge}$ has been investigated via the fusion-evaporation reaction ${}^{74}\mathrm{Ge}(\alpha ,\alpha 3n){}^{71}\mathrm{Ge}$. Collective structures including a rotational band built on the $15/2^{-}$ octupole state in ${}^{71}\mathrm{Ge}$ have been established. The observation of strong $E1$ transitions and the well-behaved rotational sequence built on the $15/2^{-}$ octupole state provide the first experimental evidence of an octupole rotational band in Ge isotopes, suggesting an enhanced octupole correlation around $N=40$ in the $A\approx 70$ region. A newly developed semimicroscopic cluster model provides a good description of the octupole characteristics of ${}^{71}\mathrm{Ge}$.

Root-mean-square charge radii are discussed in terms of spherical energy-density functional (EDF) models corrected for quadrupole deformations. We discuss the specific examples for the isotope shifts of the calcium isotopes and the isotonic shift between tin and cadmium.

The selenium isotopes lie at the heart of a tumultuous region of the nuclear chart where shape coexistence effects grapple with neutron-proton pairing correlations, triaxiality, and the impending proton drip line. In this work, a study of ${}^{72}\mathrm{Se}$ by internal conversion electron and $\gamma$-ray spectroscopy was undertaken with the SPICE and TIGRESS arrays. New measurements of the branching ratio and lifetime of the $0_2{}^{+}$ state were performed, yielding a determination of ${\rho }^2(E0;0_2{}^{+}\to 0_1{}^{+})=29\left(3\right)$ milliunits. Two-state mixing calculations were performed that highlighted the importance of interpretation of such $E0$ strength values in the context of shape coexistence.

The ${}^2\mathrm{H}(\alpha ,\gamma ){}^6\mathrm{Li}$ radiative capture responsible for the ${}^6\mathrm{Li}$ production during the big-bang nucleosynthesis is comprehensively studied within a microscopic approach. The approach implements microscopically clustering aspects of nuclear structure and dynamics in an oscillator-basis representation. The total astrophysical $S$ factor of the reaction is calculated. All allowed partial electric quadrupole and magnetic dipole transitions between the ${}^4\mathrm{He}+{}^2\mathrm{H}$ continuum and the ${}^6\mathrm{Li}$ ground state are considered in the standard long-wavelength limit. Isospin-forbidden electric dipole transitions are taken into account in two ways. The first method is based on the expression for the electric dipole operator at the leading order of the long-wavelength approximation with the usage of the exact-mass prescription. In the second method, this operator is written at the first order beyond the leading-order approximation. Contributions of the transitions are compared to each other. The ${}^4\mathrm{He}+{}^2\mathrm{H}$ nuclear phase shifts for the initial channels of the considered reaction are computed. Important properties of the ${}^6\mathrm{Li}$ nucleus, such as the breakup threshold, the asymptotic normalization constants, and the electric quadrupole moment are also described. Deformation effects and their manifestations in ${}^6\mathrm{Li}$ are discussed. The obtained results are shown to be in good agreement with a large set of experimental data.

By taking into account the magnetic field in the extended quantum molecular dynamics model, we analyzed its effects on giant dipole resonance (GDR) by studying the responses and strengths of the dipole moments. The selected system is the ${}^{40}\mathrm{Ca}$ nucleus which is excited through the Coulomb interaction by ${}^{16}\mathrm{O}$. The particle acceleration term in the Liénard-Wiechert potential is discussed which, however, has small impact on the magnetic field. The peak energy, strength, and width of GDR, temperature, and angular momentum of ${}^{40}\mathrm{Ca}$ as a function of beam energy are investigated. It is found that the magnetic field enhances the peak energy, strength, and width of GDR which is not only due to the temperature effects, but also due to the enhancement of the angular momentum of nucleus. At beam energy $E >$ 200 MeV/nucleon, the magnetic field maintains a constant value for the strength of GDR. The paper sheds light on examining important roles of the magnetic field on the nuclear structure in low-intermediate energy heavy-ion collisions.

Deuteron-induced nonelastic cross sections are studied in an extended intranuclear cascade (INC) model. A three-body framework of proton, neutron, and target is introduced into the INC model to incorporate naturally the decomposition and capture reactions from weakly bound deuterons. This framework includes three types of interaction potential, namely proton-target, neutron-target, and proton-neutron, the last of which causes the two nucleons in the deuteron to oscillate and play an important role in its breakup. The calculated results reproduce well the experimental data for ${}^{12}\mathrm{C}, {}^{40}\mathrm{Ca}, {}^{58}\mathrm{Ni}$, and ${}^{208}\mathrm{Pb}$ targets with almost the same parameters as those determined previously for nucleon-induced nonelastic reactions. It is found that the contribution of the two-nucleon collision process increases with target size, that the contribution of the capture processes is limited to a narrow region at low energy for lighter targets, and that the contribution of the breakup process is relatively small compared to other processes. It is also concluded that discrete-level-constraint effects dominate in the low-energy region for light nuclei such as ${}^{12}\mathrm{C}$, while Coulomb effects dominate in the low-energy region for heavy nuclei. This result is consistent with the INC model of nucleon incidence, which explains well the nucleon-induced nonelastic cross sections at low energies.

The study of breakup fusion of ${}^{19}\mathrm{F}$ with ${}^{154}\mathrm{Sm}$ target was studied through offline $\gamma$ ray spectrometry. Partial cross sections of evaporation residues produced in this reaction were measured in center-of-mass energies ranging $\approx \mathrm{3–30}$ MeV above the fusion barrier. The excitation functions of the evaporation residues populated through $xn/pxn$ channels were found to be satisfactorily reproduced by statistical model calculations, whereas for the $\alpha$ emitting channels the cross sections show an enhancement over the theoretical predictions. The critical angular momentum deduced from the measured cross sections was found to be in good agreement with statistical model calculations. The degree of fusion incompleteness in the ${}^{19}\mathrm{F}+{}^{154}\mathrm{Sm}$ reaction is estimated by comparing the fusion excitation functions with coupled channels calculations and the extracted fusion function with the universal fusion function. The large cross sections observed for incomplete fusion products support the interpretation that this suppression of fusion is caused by ${}^{19}\mathrm{F}$ breaking up into charged fragments before reaching the fusion barrier. The incomplete fusion probability was also found to increase with the reduced mass and charge of the entrance channel, indicating the influence of entrance channel mass asymmetry and Coulomb repulsion on incomplete fusion. The present analysis shows the presence of strong clustering in the ${}^{19}\mathrm{F}$ projectile as $\alpha$ and ${}^{15}\mathrm{N}$.