The adiabatic distorted wave approximation (ADWA) model of $A(d,p)B$ reactions is generalized to include the effects of nucleon-nucleus spin-orbit potentials and the neutron-proton tensor force and associated $D$-state terms in the interaction between the neutron and proton in the incident deuteron. The ADWA predicts that the incident channel distorting potential must include momentum-dependent rank-2 spin tensor force terms with novel properties not normally considered in the deuteron-nucleus scattering.

Experimental searches for neutrinoless double-$\beta$ decay offer one of the best opportunities to look for physics beyond the standard model. Detecting this decay would confirm the Majorana nature of the neutrino, and a measurement of its half-life can be used to determine the absolute neutrino mass scale. Important to both tasks is an accurate knowledge of the $Q$ value of the double-$\beta$ decay. The LEBIT Penning trap mass spectrometer was used for the first direct experimental determination of the ${}^{96}\mathrm{Zr}$ double-$\beta$ decay $Q$ value: $Q_{\beta \beta }=3355.85\left(15\right)$ keV. This value is nearly 7 keV larger than the 2012 Atomic Mass Evaluation [M. Wang et al., Chin. Phys. C 36, 1603 (2012)] value and one order of magnitude more precise. The 3-$\sigma$ shift is primarily due to a more accurate measurement of the ${}^{96}\mathrm{Zr}$ atomic mass: $m{(}^{96}\mathrm{Zr})=95.90827735\left(17\right)$ u. Using the new $Q$ value, the $2\nu \beta \beta$-decay matrix element, $|M_{2\nu }|$, is calculated. Improved determinations of the atomic masses of all other zirconium $\left({}^{90-92,94,96}\mathrm{Zr}\right)$ and molybdenum $\left({}^{92,94-98,100}\mathrm{Mo}\right)$ isotopes using both ${}^{12}{\mathrm{C}}_8$ and ${}^{87}\mathrm{Rb}$ as references are also reported.

The ${}^{124}\mathrm{Sn}({}^{37}\mathrm{Cl},6\mathrm{n}\gamma )$ fusion-evaporation reaction at a bombarding energy of 180 MeV has been used to significantly extend the excitation level scheme of ${}_{67}^{155}{\mathrm{Ho}}_{88}$. The collective rotational behavior of this nucleus breaks down above spin $I\sim 30$ and a fully aligned noncollective (band terminating) state has been identified at $I^{\pi }=79/2^{-}$. Comparison with cranked Nilsson–Strutinsky calculations also provides evidence for core-excited noncollective states at $I^{\pi }=87/2^{-}$ and $(89/2^{+})$ involving particle-hole excitations across the $Z=64$ shell gap. A similar core-excited state in ${}_{68}^{156}{\mathrm{Er}}_{88}$ at $I^{\pi }=\left({46}^{+}\right)$ is also presented.

In this paper we investigate the model dependence of $I^4$ term in theoretical symmetry energy for a few popular mass models. Our results show that, interestingly and unexpectedly, the coefficients of the $I^4$ term in finite nuclei extracted from different mass models correlate strongly with the corresponding root-mean-square deviations from the experimental binding energies and also with the number of bound nuclei in the nuclear landscape predicted by theoretical models. This feature suggests that the main uncertainty of symmetry energy in finite nuclei is related to the $I^4$ term.

Mass parameters for collective variables of dinuclear systems formed in cold fusion reactions are microscopically calculated with the linear response theory making use of the width of single-particle states and the fluctuation-dissipation theorem. The single-particle spectrum and potential energy surface of the adiabatic two-center shell model are used. The microscopical mass parameter in the neck is found to be much larger than one obtained with the hydrodynamical model. Therefore, the dinuclear system lives a rather long time, comparable to the characteristic time of fusion and, correspondingly, the fusion can be considered at fixed neck parameter. With an adiabatic melting of the dinuclear system along the internuclear distance into a compound system one cannot explain the experimental trends in cold fusion reactions.

The quark-gluon plasma (QGP) generated in relativistic heavy-ion collisions could be locally parity-odd. In parity-odd QGP, the electric field may induce a chiral current which is called the chiral electric separation effect (CESE). We propose two possible observables for CESE in Cu + Au collisions: The first one is the correlation ${\zeta }_{\alpha \beta }=\langle cos\left[2({\varphi }_{\alpha }+{\varphi }_{\beta }-2{\Psi }_{\mathrm{RP}})\right]\rangle$; the second one is the charge-dependent event-plane angle ${\Psi }_2^q$ with $q=\pm$ being charge. Nonzero $\Delta \zeta ={\zeta }_{\mathrm{opp}}-{\zeta }_{\mathrm{same}}$ and $\Delta \Psi =\langle |{\Psi }_2^{+}-{\Psi }_2^{-}|\rangle$ may signal the CESE in Cu + Au collisions. Within a multiphase transport model, we study how the final state interaction affects these observables. We find that the correlation ${\gamma }_{\alpha \beta }=\langle cos({\varphi }_{\alpha }+{\varphi }_{\beta }-{\Psi }_{\mathrm{RP}})\rangle$ is sensitive to the out-of-plane charge separation caused by the chiral magnetic effect and to the in-plane charge separation caused by the in-plane electric field, but it is not sensitive to the CESE. On the other hand, $\Delta \zeta$ and $\Delta \Psi$ are sensitive to the CESE. Therefore, we suggest that future experiments measure the above observables in Cu + Au collisions in order to disentangle different chiral and charge separation mechanisms.

The nucleon exchange mechanism is investigated in central collisions of symmetric heavy ions in the basis of the stochastic mean-field approach. Quantal diffusion coefficients for nucleon exchange are calculated by including non-Markovian effects and shell structure. Variances of fragment mass distributions are calculated in central collisions of ${}^{40}\mathrm{Ca}$ + ${}^{40}\mathrm{Ca},{}^{48}\mathrm{Ca}$ + ${}^{48}\mathrm{Ca}$, and ${}^{56}\mathrm{Ni}$ + ${}^{56}\mathrm{Ni}$ systems.

With the goal of developing predictive ab initio capability for light and medium-mass nuclei, two-nucleon and three-nucleon forces from chiral effective field theory are optimized simultaneously to low-energy nucleon-nucleon scattering data, as well as binding energies and radii of few-nucleon systems and selected isotopes of carbon and oxygen. Coupled-cluster calculations based on this interaction, named ${\mathrm{NNLO}}_{\mathrm{sat}}$, yield accurate binding energies and radii of nuclei up to ${}^{40}\mathrm{Ca}$, and are consistent with the empirical saturation point of symmetric nuclear matter. In addition, the low-lying collective $J^{\pi }=3^{-}$ states in ${}^{16}\mathrm{O}$ and ${}^{40}\mathrm{Ca}$ are described accurately, while spectra for selected $p$- and $sd$-shell nuclei are in reasonable agreement with experiment.

Background: The neutron-rich calcium isotopes have gained particular interest as evidence of closed-shell structures has recently been found in two exotic nuclei, at $N=32$ and $N=34$. Additionally, the study of such neutron-rich systems has revealed new aspects of nuclear forces, in particular regarding the role of three-nucleon forces.

Purpose: We study the electromagnetic properties of Ca isotopes around the neutron number $N=32$.

Methods: High-resolution bunched-beam collinear laser spectroscopy was used to measure the optical hyperfine spectra of the ${}^{43-51}\mathrm{Ca}$ isotopes.

Results: The ground-state magnetic moments of ${}^{49,51}\mathrm{Ca}$ and quadrupole moments of ${}^{47,49,51}\mathrm{Ca}$ were measured for the first time, and the ${}^{51}\mathrm{Ca}$ ground-state spin $I=3$/2 was determined in a model-independent way. Our experimental results are compared with state-of-the-art shell-model calculations using both phenomenological interactions and microscopic interactions derived from chiral effective field theory.

Conclusions: The results for the ground-state moments of neutron-rich isotopes are in excellent agreement with predictions of interactions derived from chiral effective field theory including three-nucleon forces. Lighter isotopes illustrate the presence of particle-hole excitations of the ${}^{40}\mathrm{Ca}$ core in their ground state. Our results provide a critical test of modern nuclear theories, and give direct answer to the evolution of ground-state electromagnetic properties in the Ca isotopic chain across three doubly closed-shell configurations at $N=20$, 28, 32 of this unique system.

Dynamical calculations based on the four-dimensional stochastic Langevin approach are extended to the description of fragment isotopic distributions in fission at moderate-to-high excitation energy. Benefiting from previous theoretical work on charge-asymmetry relaxation times, and existing experimental charge-dispersion curves from low-energy fission, charge fluctuations are introduced at the scission point in an effective way. Comparison with recent suited measurements shows a good description over the full fragment production. The development proposed in this work can easily be implemented in other codes used in the field.

The effect of temperature $T$ and angular momentum $J$ on the inverse level density parameter $k$ has been studied by populating the compound nucleus ${}^{97}\mathrm{Tc}$ in the reaction ${}^4\mathrm{He}+{}^{93}\mathrm{Nb}$ at four incident beam energies of 28, 35, 42, and 50 MeV. For all four energies, the value of $k$ decreases with increasing $J$. The $T$ dependence of $k$ has been compared for two angular momentum windows with different theoretical predictions as well as with the finite-temperature BCS calculation which takes into account the quasiparticle-number fluctuations in the pairing field (FTBCS1). Interestingly, the experimental data are in good agreement with the theoretical calculations at higher $J$ but deviate from all the calculations at lower $J$.

An extensive study of the level structure of ${}^{61}\mathrm{Co}$ has been performed following the complex ${}^{26}\mathrm{Mg}({}^{48}\mathrm{Ca},2\alpha 4np\gamma ){}^{61}\mathrm{Co}$ reaction at beam energies of 275, 290, and 320 MeV using Gammasphere and the Fragment Mass Analyzer (FMA). The low-spin structure is discussed within the framework of shell-model calculations using the GXPF1A effective interaction. Two quasirotational bands consisting of stretched-$E2$ transitions have been established up to spins $I=41/2$ and $(43/2)$, and excitation energies of $\sim 17$ and $\sim 20$ MeV, respectively. These are interpreted as signature partners built on a neutron $\nu {\left(g_{9/2}\right)}^2$ configuration coupled to a proton $\pi p_{3/2}$ state, based on cranked shell model (CSM) calculations and comparisons with observations in neighboring nuclei. In addition, four $\Delta I=1$ bands were populated to high spin, with the yrast dipole band interpreted as a possible candidate for the shears mechanism, a process seldom observed thus far in this mass region.

The photoresponse of ${}^{52}\mathrm{Cr}$ has been investigated in the energy range of 5.0–9.5 MeV using the photon scattering technique at the $\mathrm{HI}\gamma \mathrm{S}$ facility of TUNL to complement previous work with unpolarized bremsstrahlung photon beams at the Darmstadt linear electron accelerator. The unambiguous parity determinations of the observed $J=1$ states provides the basis needed to better understand the structure of $E1$ and $M1$ excitations. Theoretical calculations using the quasiparticle phonon model incorporating self-consistent energy-density functional theory were performed to investigate the fragmentation pattern of the dipole strength below and around the neutron-emission threshold. These results compare very well with the experimental values.

The self-consistent tilted axis cranking relativistic mean-field (TAC-RMF) theory based on a point-coupling interaction is applied to investigate the observed magnetic and antimagnetic rotations in the nucleus ${}^{110}\mathrm{Cd}$. The energy spectra, the relation between the spin and the rotational frequency, the deformation parameters, and the reduced $M1$ and $E2$ transition probabilities are studied with the various configurations. It is found that the configuration has to be changed to reproduce the energy spectra and the relations between the spin and the rotational frequency for both the magnetic and antimagnetic rotational bands. The shears mechanism for the magnetic rotation and the two-shears-like mechanism for the antimagnetic rotation are examined by investigating the orientation of the neutron and proton angular momenta. The calculated electromagnetic transitions $B\left(M1\right)$ and $B\left(E2\right)$ are in reasonable agreement with the data, and their tendencies are coincident with the typical characteristics of the magnetic and antimagnetic rotations.

We re-examine the well-known Wong formula for heavy-ion fusion cross sections. Although this celebrated formula yields almost-exact results for single-channel calculations for relatively heavy systems such as ${}^{16}\mathrm{O}+{}^{144}\mathrm{Sm}$, it tends to overestimate the cross section for light systems such as ${}^{12}\mathrm{C}+{}^{12}\mathrm{C}$. We generalize the formula to take account of the energy dependence of the barrier parameters and show that the energy-dependent version gives results practically indistinguishable from a full quantal calculation. We then examine the deviations arising from the discrete nature of the intervening angular momenta, whose effect can lead to an oscillatory contribution to the excitation function. We recall some compact, analytic expressions for these oscillations and highlight the important physical parameters that give rise to them. Oscillations in symmetric systems are discussed, as are systems where the target and projectile identities can be exchanged via a strong transfer channel.

The measurements of complete fusion cross sections for ${}^6\mathrm{Li}+{}^{96}\mathrm{Zr}$ have been performed at energies around the Coulomb barrier by the online $\gamma$-ray method. The complete fusion cross sections at above-barrier energies were found to be suppressed by $\sim 25\%$. A comparison of the systematics of complete fusion suppression with the existing data for ${}^6\mathrm{Li}$+ heavy targets with the present results shows that the systematics of the suppression factor observed for ${}^6\mathrm{Li}$-induced fusion in the heavy mass region may not be consistent in lighter target mass region.

Constraining the excitation energy at which the nuclear shell effect washes out has important implications on the production of superheavy elements and many other fields of nuclear physics research. We report the fission fragment mass distribution in $\alpha$ induced reaction on an actinide target for wide excitation range in close energy interval and show direct evidence that the nuclear shell effect washes out at excitation energy $\sim 40$ MeV. The calculation shows that the second peak of the fission barrier also vanishes around similar excitation energy.

Evaporation residue (ER) cross sections for the ${}^{16,18}\mathrm{O}+{}^{198}\mathrm{Pt}$ reactions are measured in order to investigate fission hindrance. Compound nuclei (${}^{214,216}\mathrm{Rn}$) are formed in the above fusion reactions at excitation energies in the range of 40–68 MeV. The experimental ER cross sections are compared with predictions from the statistical model calculations of compound nuclear decay where Kramers' fission width is used. The strength of nuclear dissipation is treated as a free parameter in the statistical model calculations in order to fit the experimental data.