Transition probabilities of intermediate-spin yrast and non-yrast excitations in ${}^{80,82}\mathrm{Se}$ were investigated in a recoil distance Doppler-shift (RDDS) experiment performed at the Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro. The Cologne Plunger device for deep inelastic scattering was used for the RDDS technique and was combined with the AGATA Demonstrator array for the $\gamma$-ray detection and coupled to the PRISMA magnetic spectrometer for an event-by-event particle identification. In ${}^{80}\mathrm{Se}$, the level lifetimes of the yrast ($6_1^{+}$) and ($8_1^{+}$) states and of a non-yrast band feeding the yrast $4_1^{+}$ state are determined. A spin and parity assignment of the head of this sideband is discussed based on the experimental results and supported by large-scale shell-model calculations. In ${}^{82}\mathrm{Se}$, the level lifetimes of the yrast $6_1^{+}$ state and the yrare $4_2^{+}$ state and lifetime limits of the yrast (${10}_1^{+}$) state and of the $5_1^{-}$ state are determined. Although the experimental results contain large uncertainties, they are interpreted with care in terms of large-scale shell-model calculations using the effective interactions JUN45 and jj44b. The excited states' wave functions are investigated and discussed with respect to the role of the neutron $g_{9/2}$ orbital.

The elastic scattering angular distributions were measured for 50- and 59-MeV ${}^{17}\mathrm{F}$ radioactive ion beam on a ${}^{89}\mathrm{Y}$ target. The aim of this work is to study the effect of the breakup of the proton halo projectile on the elastic scattering angular distribution. The experimental data were analyzed by means of the optical model with the double-folding São Paulo potential for both real and imaginary parts. The theoretical calculations reproduced the experimental data reasonably well. It is shown that the method of the data analysis is correct. In order to clarify the difference observed at large angles for the 59-MeV incident energy data, Continuum-Discretized Coupled-Channels (CDCC) calculations were performed to consider the breakup coupling effect. It is found that the experimental data show the Coulomb rainbow peak and that the effect of the coupling to the continuum states is not very significant, producing only a small hindrance of the Coulomb rainbow peak and a very small enhancement of the elastic scattering angular distribution at backward angles, suggesting that the multipole response of the neutron halo projectiles is stronger than that of the proton halo systems.

An evident odd-even staggering (OES) in fragment cross sections has been experimentally observed in many fragmentation and spallation reactions. However, quantitative comparisons of this OES effect in different reaction systems are still scarce for neutron-rich nuclei near the neutron drip line. By employing a third-order difference formula, the magnitudes of this OES in extensive experimental cross sections are systematically investigated for many neutron-rich nuclei with ($N-Z$) from 1 to 23 over a broad range of atomic numbers ($Z\approx 3–50$). A comparison of these magnitude values extracted from fragment cross sections measured in different fragmentation and spallation reactions with a large variety of projectile-target combinations over a wide energy range reveals that the OES magnitude is almost independent of the projectile-target combinations and the projectile energy. The weighted average of these OES magnitudes derived from cross sections accurately measured in different reaction systems is adopted as the evaluation value of the OES magnitude. These evaluated OES magnitudes are recommended to be used in fragmentation and spallation models to improve their predictions for fragment cross sections.

With the newly updated version of the ultrarelativistic quantum molecular dynamics (UrQMD) model, a systematic investigation of the effects of in-medium nucleon-nucleon ($\mathit{NN}$) elastic cross section on the collective flow and the stopping observables in ${}^{197}\mathrm{Au}+{}^{197}\mathrm{Au}$ collisions at beam energies from 40 to 150 MeV/nucleon is performed. Simulations with the medium correction factors $\mathcal{F}={\sigma }_{NN}^{\mathrm{in}\text{−}\mathrm{medium}}/{\sigma }_{NN}^{\mathrm{free}}=0.2,0.3,0.5$ and the one obtained with the FU3FP1 parametrization which depends on both the density and the momentum are compared to the FOPI and INDRA experimental data. It is found that, to best fit the experimental data of the slope of the directed flow and the elliptic flow at midrapidity as well as the nuclear stopping, the correction factors of $\mathcal{F}=0.2$ and 0.5 are required for reactions at beam energies of 40 and 150 MeV/nucleon, respectively. Whereas calculations with the FU3FP1 parametrization can simultaneously reproduce these experimental data reasonably well. And, the observed increasing nuclear stopping with increasing beam energy in experimental data can also be reproduced by using the FU3FP1 parametrization, whereas the calculated stopping power in Au + Au collisions with beam energies from 40 to $150\mathrm{MeV}/\mathrm{nucleon}$ almost remains constant when taking $\mathcal{F}$ equal to a fixed value.

Vorticity generated in heavy-ion collisions at energy of $\sqrt{s_{NN}}=39\mathrm{GeV}$ is studied. Simulations are performed within a model of the three-fluid dynamics. A peculiar structure consisting of two vortex rings is found: one ring in the target fragmentation region and another one in the projectile fragmentation region. These rings are also formed in central collisions. The matter rotation is opposite in this two rings. These vortex rings are already formed at the early stage of the collision together with primordial fragmentation regions. The average vorticity, responsible for the global polarization of the observed $\mathrm{\Lambda }$ and $\overline{\mathrm{\Lambda }}$, is also studied. In the semicentral collisions the average vorticity in the midrapidity region turns out to be more than an order of magnitude lower than the total one. The total vorticity is dominated by the contributions of the fragmentation regions and is produced because of asymmetry of the vortex rings in noncentral collisions. This suggests that in semicentral collisions the global polarization in the fragmentation regions should be at least an order of magnitude higher than that observed by the STAR collaboration in the midrapidity. This polarization should be asymmetrical in the reaction plain and correlate with the corresponding directed flow.

In this paper, with restored isospin symmetry, we evaluated the neutrinoless double-$\beta$-decay nuclear matrix elements for ${}^{76}\mathrm{Ge}, {}^{82}\mathrm{Se}, {}^{130}\mathrm{Te}, {}^{136}\mathrm{Xe}$, and ${}^{150}\mathrm{Nd}$ for both the light and heavy neutrino mass mechanisms using the deformed quasiparticle random-phase approximation approach with realistic forces. We give detailed decompositions of the nuclear matrix elements over different intermediate states and nucleon pairs, and discuss how these decompositions are affected by the model space truncations. Compared to the spherical calculations, our results show reductions from $30\%$ to about $60\%$ of the nuclear matrix elements for the calculated isotopes mainly due to the presence of the BCS overlap factor between the initial and final ground states. The comparison between different nucleon-nucleon (NN) forces with corresponding short-range correlations shows that the choice of the NN force gives roughly $20\%$ deviations for the light exchange neutrino mechanism and much larger deviations for the heavy neutrino exchange mechanism.

In the present work, we systematically study the $\alpha$ decay preformation factors $P_{\alpha }$ within the cluster-formation model and $\alpha$ decay half-lives by the proximity potential 1977 formalism for nuclei around $Z=82,N=126$ closed shells. The calculations show that the realistic $P_{\alpha }$ is linearly dependent on the product of valance protons (holes) and valance neutrons (holes) $N_p{N}_n$. It is consistent with our previous works [Sun et al., Phys. Rev. C 94, 024338 (2016); Deng et al., Phys. Rev. C 96, 024318 (2017)], in which $P_{\alpha }$ are model dependent and extracted from the ratios of calculated $\alpha$ half-lives to experimental data. Combining with our previous works, we confirm that the valance proton-neutron interaction plays a key role in the $\alpha$ preformation for nuclei around $Z=82,N=126$ shell closures whether the $P_{\alpha }$ is model dependent or microcosmic. In addition, our calculated $\alpha$ decay half-lives by using the proximity potential 1977 formalism taking $P_{\alpha }$ evaluated by the cluster-formation model can well reproduce the experimental data and significantly reduce the errors.

Natural copper is commonly used as cooling and shielding medium in detector arrangements designed to search for neutrinoless double-$\beta$ decay. Neutron-induced background reactions on copper could potentially produce signals that are indistinguishable from the signals of interest. The present work focuses on radiative neutron capture experiments on ${}^{63,65}\mathrm{Cu}$ in the 0.4 to 7.5 MeV neutron energy range. The new data provide evaluations and model calculations with benchmark data needed to extend their applicability in predicting background rates in neutrinoless double-$\beta$ decay experiments.

I investigate modifications of mass and decay width of $N^{*}\left(1535\right)$ in nuclear matter in a chiral symmetric way. The nucleon and $N^{*}\left(1535\right)$ are introduced by a parity doublet model, and nuclear matter is constructed by one-loop diagrams of the nucleon and $N^{*}\left(1535\right)$. The decay width of $N^{*}\left(1535\right)$ is studied with respect to chiral symmetry. My calculations show that the partial width of ${\mathrm{\Gamma }}_{N^{*}\to N\pi }$ is slightly broadened by a collisional broadening and that of ${\mathrm{\Gamma }}_{N^{*}\to N\eta }$ is drastically suppressed at density. As a result, the total decay width ${\mathrm{\Gamma }}_{\mathrm{tot}}$ gets small at density. These modifications, especially the drastic narrowing of partial width of ${\mathrm{\Gamma }}_{N^{*}\to N\eta }$, together with the drop in mass of $N^{*}\left(1535\right)$, provide experiments for observing the partial restoration of chiral symmetry in nuclear matter by means of $N^{*}\left(1535\right)$ resonance with useful information.

Structure functions, as measured in lepton-nucleon scattering, have proven to be very useful in studying the partonic dynamics within the nucleon. However, it is experimentally difficult to separately determine the longitudinal and transverse structure functions, and consequently there are substantially less data available in particular for the longitudinal structure function. Here, we present separated structure functions for hydrogen and deuterium at low four-momentum transfer squared, $Q^2<1{\mathrm{GeV}}^2$, and compare them with parton distribution parametrization and $k_T$ factorization approaches. While differences are found, the parametrizations generally agree with the data, even at the very low-$Q^2$ scale of the data. The deuterium data show a smaller longitudinal structure function and a smaller ratio of longitudinal to transverse cross section, $R$, than the proton. This suggests either an unexpected difference in $R$ for the proton and the neutron or a suppression of the gluonic distribution in nuclei.

The unique isomeric transition at 7.8 eV in ${}^{229}\mathrm{Th}$ has a magnetic-dipole ($M1$) and an electric-quadrupole ($E2$) multipole mixing. So far, the $E2$ component has been widely disregarded. Here, we investigate the nuclear physics nature and the impact of the $E2$ decay channel for the nuclear coupling to the atomic shell based on the newest theoretical predictions for the corresponding reduced nuclear transition probabilities. Our results show that the contribution of the $E2$ channel is dominant or at least of the same order of magnitude for internal conversion or electronic bridge transitions involving the atomic orbitals $7p, 6d$, and $5f$. Notable exceptions are the internal conversion of the $7s$ electron and the electronic bridge between the electronic states $7s$ and $7p$, for which the $M1$ component dominates by two to three orders of magnitude. Caution is therefore advised when considering isomeric excitation or decay via nuclear coupling to the atomic shell, because the orbitals involved determine which multipole transition component dominates.

We report on the in-beam gamma spectroscopy of ${}^{102}\mathrm{Sn}$ and ${}^{100}\mathrm{Cd}$ produced via two-neutron removal from carbon and ${\mathrm{CH}}_2$ targets at about 150 MeV/nucleon beam energy. New transitions assigned to the decay of a second $2^{+}$ excited state at 2470(60) keV in ${}^{102}\mathrm{Sn}$ were observed. Two-neutron removal cross sections from ${}^{104}\mathrm{Sn}$ and ${}^{102}\mathrm{Cd}$ have been extracted. The enhanced cross section to the $2_2^{+}$ in ${}^{102}\mathrm{Sn}$ populated via the $(p,p2n)$ reaction is traced back to an increase of shell-model structure overlaps, consistent with the hypothesis that the proton-induced two-deeply bound-nucleon removal mechanism is of direct nature.

Background: ${}^{12}\mathrm{C}$ has been and is still widely used in neutrino-nucleus scattering and oscillation experiments. More recently, ${}^{40}\mathrm{Ar}$ has emerged as an important nuclear target for current and future experiments. Liquid argon time projection chambers (LArTPCs) possess various advantages in measuring electroweak neutrino-nucleus cross sections. Concurrent theoretical research is an evident necessity.

Purpose: ${}^{40}\mathrm{Ar}$ is larger than ${}^{12}\mathrm{C}$, and one expects nuclear effects to play a bigger role in reactions. We present inclusive differential and total cross section results for charged-current neutrino scattering on ${}^{40}\mathrm{Ar}$ and perform a comparison with ${}^{12}\mathrm{C}, {}^{16}\mathrm{O}$, and ${}^{56}\mathrm{Fe}$ targets, to find out about the $A$-dependent behavior of model predictions.

Method: Our model starts off with a Hartree-Fock description of the nucleus, with the nucleons interacting through a mean field generated by an effective Skyrme force. Long-range correlations are introduced by means of a continuum random phase approximation approach. Further methods to improve the accuracy of model predictions are also incorporated in the calculations.

Results: We present calculations for ${}^{12}\mathrm{C}, {}^{16}\mathrm{O}, {}^{40}\mathrm{Ar}$, and ${}^{56}\mathrm{Fe}$, showcasing differential cross sections over a broad range of kinematic values in the quasielastic regime. We furthermore show flux-folded results for ${}^{40}\mathrm{Ar}$ and we discuss the differences between nuclear responses.

Conclusions: At low incoming energies and forward scattering we identify an enhancement in the ${}^{40}\mathrm{Ar}$ cross section compared to ${}^{12}\mathrm{C}$, as well as in the high $\omega$ (low $T_{\mu }$) region across the entire studied $E_{\nu }$ range. The contribution to the folded cross section of the reaction strength at values of $\omega$ lower than 50 MeV for forward scattering is sizable.

Three- and two-level mixing models are proposed to understand the doubling of states at the same spin and parity in triaxially deformed atomic nuclei with odd numbers of protons and neutrons. The particle-rotor model for such nuclei is solved using the newly proposed basis which couples angular momenta of two valence nucleons and the rotating triaxial mean field into left-handed $|\mathcal{L}\rangle$, right-handed $|\mathcal{R}\rangle$, and planar $|\mathcal{P}\rangle$ configurations. The presence and impact of the planar component is investigated as a function of the total spin for mass $\mathrm{A}\approx 130$ nuclei with the valence $h_{11/2}$ proton particle, valence $h_{11/2}$ neutron hole, and the maximum difference between principal axes allowed by the quadrupole deformation of the mean field. It is concluded that at each spin value the higher energy member of a doublet of states is built on the antisymmetric combination of $|\mathcal{L}\rangle$ and $|\mathcal{R}\rangle$ and is free of the $|\mathcal{P}\rangle$ component, indicating that it is of pure chiral geometry. For the lower energy member of the doublet, the contribution of the $|\mathcal{P}\rangle$ component to the eigenfunction first decreases and then increases as a function of the total spin. This trend as well as the energy splitting between the doublet states are both determined by the Hamiltonian matrix elements between the planar ($|\mathcal{P}\rangle$) and nonplanar ($|\mathcal{L}\rangle$ and $|\mathcal{R}\rangle$) subspaces of the full Hilbert space.

Large basis shell model calculations with various particle truncations have been carried out to identify the ${}^{30}\mathrm{Si}+\alpha$ cluster states at lower excitation energy ($<12$ MeV) in the non-$\alpha$-conjugate nucleus ${}^{34}\mathrm{S}$. The states of interest in ${}^{34}\mathrm{S}$ have been calculated and correlated to the cluster SD states in ${}^{35}\mathrm{Cl}$ and ${}^{36}\mathrm{Ar}$ in terms of one and two nucleon transfer spectroscopic factors, respectively, obtained from large basis shell model calculations.

Quantum Monte Carlo methods have recently been employed to study properties of nuclei and infinite matter using local chiral effective-field-theory interactions. In this work, we present a detailed description of the auxiliary field diffusion Monte Carlo algorithm for nuclei in combination with local chiral two- and three-nucleon interactions up to next-to-next-to-leading order. We show results for the binding energy, charge radius, charge form factor, and Coulomb sum rule in nuclei with $3\le A\le 16$. Particular attention is devoted to the effect of different operator structures in the three-body force for different cutoffs. The outcomes suggest that local chiral interactions fit to few-body observables give a very good description of the ground-state properties of nuclei up to ${}^{16}\mathrm{O}$, with the exception of one fit for the softer cutoff which predicts overbinding in larger nuclei.

We test the Coulomb exchange and correlation energy density functionals of electron systems for atomic nuclei in the local density approximation (LDA) and the generalized gradient approximation (GGA). For the exchange Coulomb energies, it is found that the deviation between the LDA and GGA ranges from around 11% in ${}^4\mathrm{He}$ to around 2.2% in ${}^{208}\mathrm{Pb}$, by taking the Perdew-Burke-Ernzerhof (PBE) functional as an example of the GGA. For the correlation Coulomb energies, it is shown that those functionals of electron systems are not suitable for atomic nuclei.

The decay properties of the isotopes of $Z=125$ within the range 303 ≤ $A$ ≤ 339 are investigated. The calculation of proton separation energies reveals that isotopes ${}^{303-309}125$ may decay through proton emission. Four different mass tables are used to show the sensitivity of the mass models used to calculate the $Q$ values as well as the α-decay half-lives. $\alpha$-decay chains are predicted by comparing the α half-lives calculated within the Coulomb and proximity potential model for deformed nuclei (CPPMDN) [Nucl. Phys. A 850, 34 (2011)] with the spontaneous fission half-lives using the shell-effect-dependent formula [Phys. Rev. C 94, 054621 (2016)]. It is seen that isotopes ${}^{310,311}125$ show 6α chains. 5α chains can be seen from isotopes ${}^{312-318}125$. Isotopes ${}^{319,320}125$ exhibit 2α chains and ${}^{323}125$ exhibits 1α chain. All the other isotopes, that is, ${}^{321,322,324-339}125$ may decay through spontaneous fission. The α half-lives using CPPMDN are compared with five other theoretical formalisms and are seen to be matching with each other. We hope that our studies will be helpful in designing future experiments to explore the island of stability.

We show in detailed numerical solutions of the nonlinear Fokker-Planck equation (FPE), which has been associated with nonextensive $q$ statistics, that the available data on rapidity distributions for stopping in relativistic heavy-ion collisions cannot be reproduced with any permitted value of the nonextensivity parameter ($1<q<1.5$). This casts doubt on the nonextensivity concept that is widely used in relativistic heavy-ion physics.