By following the conventional similarity renormalization group (SRG) expansion of the Dirac equation developed in [J.-Y. Guo, Phys. Rev. C 85, 021302 (2012)], we work out the analytic expression of the $1/M^4$ order and verify the convergence of this method. As a step further, the reconstituted SRG method is proposed by using the resummation technique. The speed of convergence of the reconstituted SRG becomes much faster than the conventional one, and the single-particle densities with the reconstituted SRG are also almost identical to the exact values.

Lifetime measurements of excited states in ${}^{178}\mathrm{Hg}$ have been performed using the ${}^{103}\mathrm{Rh}({}^{78}\mathrm{Kr},p2n)$ reaction at a beam energy of 354 MeV. The recoil-decay tagging (RDT) technique was applied to select the ${}^{178}\mathrm{Hg}$ nuclei and associate the prompt $\gamma$ rays with the correlated characteristic ground-state $\alpha$ decay. Lifetimes of the four lowest yrast states of ${}^{178}\mathrm{Hg}$ have been determined using the recoil distance Doppler-shift (RDDS) method. The experimental data are compared to theoretical predictions with focus on shape coexistence. The results confirm the shift of the deformed prolate structures to higher lying states but also indicate their increasing deformation with decreasing neutron number.

In the study of neutrino and antineutrino interactions in the GeV regime, kinematic imbalances of the final-state particles have sensitivities to different nuclear effects. Previous ideas based on neutrino quasielastic interactions [Lu, et al., Phys. Rev. C 94, 015503 (2016); Furmanski and Sobczyk, Phys. Rev. C 95, 065501 (2017)] are now generalized to antineutrino quasielastic interactions, as well as neutrino and antineutrino pion productions. Measurements of these generalized final-state correlations could provide unique and direct constraints on the nuclear response inherently different for neutrinos and antineutrinos and, therefore, delineate effects that could mimic charge-parity violation in neutrino oscillations.

The agreement of the nuclear equation of state (EOS) deduced from the GW170817-based tidal deformability with the one obtained from empirical data on microscopic nuclei is examined. It is found that suitably chosen experimental data on isoscalar and isovector modes of nuclear excitations together with the observed maximum neutron star mass constrain the EOS which displays a very good congruence with the GW170817 inspired one. The giant resonances in nuclei are found to be instrumental in limiting the tidal deformability parameter and the radius of a neutron star in somewhat narrower bounds. At the $1\sigma$ level, the values of the canonical tidal deformability ${\mathrm{\Lambda }}_{1.4}$ and the neutron star radius $R_{1.4}$ come out to be $267\pm 144$ and $11.6\pm 1.0$ km, respectively.

Analytical expressions of the total number of $J$ levels for three and four fermions in a nuclear $j^n$ shell are provided. The formulas were derived using a combination of sum rules for coefficients of fractional parentage and “unusual” identities, i.e., those which do not contain the weighting factor $(2J+1)$ involving $6j$ and $9j$ symbols.

This paper presents results from partial-wave analyses of the photoproduction reactions $\gamma p\to \eta p$ and $\gamma n\to \eta n$. World data for the observables $d\sigma /d\mathrm{\Omega }, \mathrm{\Sigma }, T, P, F$, and $E$ were analyzed as part of this work. The dominant amplitude in the fitting range from threshold to a c.m. energy of 1900 MeV was found to be $S_{11}$ in both reactions, consistent with results of other groups. At c.m. energies above 1600 MeV, our solution deviates from published results, with this work finding higher-order partial waves becoming significant. Data off the proton suggest that the higher-order terms contributing to the reaction include $P_{11}, P_{13}$, and $F_{15}$. The final results also hint that $F_{17}$ is needed to fit double-polarization observables above 1900 MeV. Data off the neutron show a contribution from $P_{13}$, as well as strong contributions from $D_{13}$ and $D_{15}$.

Results from a partial-wave analysis of the reaction $\gamma p\to K^{+}\mathrm{\Lambda }$ are presented. The reaction is dominated by the $S_{11}\left(1650\right)$ and $P_{13}\left(1720\right)$ resonances at low energies and by $P_{13}\left(1900\right)$ at higher energies. There are small contributions from all amplitudes up to and including $G_{17}$, with $F_{17}$ necessary for obtaining a good fit of several of the spin observables. We find evidence for $P_{11}$(1880), $D_{13}$(2120), and $D_{15}$(2080) resonances, as well as a possible $F_{17}$ resonance near 2300 MeV, which is expected from quark-model predictions. Some predictions for $\gamma n\to K^0\mathrm{\Lambda }$ are also included.

Results are presented for an updated multichannel energy-dependent partial-wave analysis of $\pi N$ scattering. Our earlier work incorporated single-energy amplitudes for $\pi N\to \pi N, \gamma N\to \pi N, \pi N\to \pi \pi N, \pi N\to \eta N$, and $\pi N\to K\mathrm{\Lambda }$. The present work incorporates new single-energy solutions for $\gamma p\to \eta p$ up to a center-of-mass (c.m.) energy of 1990 MeV, $\gamma p\to K^{+}\mathrm{\Lambda }$ up to a c.m. energy of 2230 MeV, and $\gamma n\to \eta n$ up to a c.m. energy of 1885 MeV, as well as updated single-energy solutions for $\pi N\to \eta N, \pi N\to K\mathrm{\Lambda }$, and $\gamma N\to \pi N$. In this paper, we present and discuss the resonance parameters obtained from a combined fit of all these single-energy amplitudes. Our determined energy-dependent amplitudes provide an excellent description of the corresponding measured observables.

An accurate knowledge of nuclear parton distribution functions (nPDFs) is an essential ingredient of high energy physics calculations when the processes involve nuclei in the initial state. It is well known now that the prompt photon production in both hadronic and nuclear collisions is a powerful tool for exploring the parton densities in the nucleon and nuclei, especially of the gluon. In this work, we are going to perform a comprehensive study of the isolated prompt photon production in $p$-Pb collisions at backward rapidities to find the best kinematic regions in which the experimental measurements have most sensitivity to the nuclear modifications of parton densities. Most emphasis will be placed on the antishadowing nuclear modification. To this aim, we calculate and compare various quantities at different values of center-of-mass energy covered by the CERN Large Hadron Collider and also different rapidity regions to realize which one is most useful.

Improving our understanding of the origin of the elements in the observable universe as well as the nature of the environments responsible for their production has been of paramount importance to the nuclear physics community. More than half of the isotopes of these elements are created via neutron-capture processes, and thus accurate measurements of the salient underlying nuclear physics, such as neutron-capture cross sections, masses, and $\beta$-decay half-lives are crucial. Of particular importance to the synthesis of isotopes in the mass range of $A\approx 60$ to $A\approx 90$, via the weak $s$ process, are the neutron-capture cross sections of ${}^{63,65}\mathrm{Cu}$, where large discrepancies between measurements exist. Recent measurements have addressed these discrepancies for ${}^{63}\mathrm{Cu}$ [Weigand et al., Phys. Rev. C 95, 015808 (2017)], but questions still remain for ${}^{65}\mathrm{Cu}$. In this paper we report a new measurement of the ${}^{65}\mathrm{Cu}(n,\gamma )$ cross section performed using the Detector for Advanced Neutron Capture Experiments located at the Los Alamos Neutron Science Center of Los Alamos National Laboratory. The Maxwellian-averaged cross section (MACS) for ${}^{65}\mathrm{Cu}(n,\gamma )$ at $kT=30$ keV deduced from this work is ($37.0\pm 0.3_{\mathrm{stat}.}\pm 3.3_{\mathrm{sys}.}$) mb. The impact on weak $s$-process nucleosynthesis of new MACS values, calculated over the range of $kT=5$ to 100 keV, for ${}^{65}\mathrm{Cu}$, combined with the updated MACS for ${}^{63}\mathrm{Cu}$ [Weigand et al., Phys. Rev. C 95, 015808 (2017)] and ${}^{63}\mathrm{Ni}$ [Weigand et al., Phys. Rev. C 92, 045810 (2015)], were investigated. Results of this investigation show an increase of predicted nucleosynthesis yields of elements of Zn to Zr by as much as 20% .

A simple two-state mixing model has been applied to the $0^{+}, 2^{+}$, and $4^{+}$ states in the first two $0^{+}$ bands in ${}^{76}\mathrm{Se}$. The first two $0^{+}$ states are found to be almost maximally mixed. The excited basis-state band has the energy and E2 strengths characteristic of a $K=0$ rotational band, but the lower basis-state band does not. The $e$ band is significantly more collective than the $g$ band.

The mirror seven-nucleon ${}^4\mathrm{He}+{}^3\mathrm{H}$ and ${}^4\mathrm{He}+{}^3\mathrm{He}$ systems are studied microscopically using the algebraic version of the resonating group model. Astrophysical $S$ factors and branching ratios for the ${}^3\mathrm{H}(\alpha ,\gamma ){}^7\mathrm{Li}$ and ${}^3\mathrm{He}(\alpha ,\gamma ){}^7\mathrm{Be}$ radiative captures are calculated in a wide energy range from ultralow energies to intermediate ones covering the ${}^7\mathrm{Li}$ and ${}^7\mathrm{Be}$ lowest resonance states. All allowed E1, E2, and M1 captures from $s, p, d$, and $f$ waves are taken into account in the calculations. Nuclear phase shifts for the ${}^3\mathrm{H}(\alpha ,\alpha ){}^3\mathrm{H}$ and ${}^3\mathrm{He}(\alpha ,\alpha ){}^3\mathrm{He} s$-, $p$-, $d$-, and $f$-wave elastic scattering are computed. Properties of the bound and low-lying resonance states of the ${}^7\mathrm{Li}$ and ${}^7\mathrm{Be}$ nuclei are considered. The obtained results are compared with data from experiments.

The isomer yield ratios of ${}^{184}\mathrm{Re}$ in the incomplete fusion of the ${}^9\mathrm{Be}+{}^{181}\mathrm{Ta}$ system were measured at energies around the Coulomb barrier, using online activation followed by offline $\gamma$-ray spectroscopy method. The platypus code that is based on a classical dynamical model is employed to analyze the measurements. By applying a phenomenological approach, model calculation managed to fairly reproduce the order of magnitude of the yield ratios at above barrier energies. Through the study, it is shown that the platypus code in conjunction with a phenomenological analysis can provide a reasonable explanation of isomer yield ratios resulted from incomplete fusion of weakly bound projectiles.

The time-dependent Skyrme Hartree-Fock calculations have been performed to study ${}^{24}\mathrm{Mg}+{}^{24}\mathrm{Mg}$ collisions. The twisted boundary conditions, which can avoid finite box-size effects of the employed three-dimensional coordinate space, have been implemented. The prolate deformed ${}^{24}\mathrm{Mg}$ has been set to different orientations to study vibrations and rotations of the compound nucleus ${}^{48}\mathrm{Cr}$. Our time evolution results show that continuum damping effects associated with the twist-averaged boundary condition play a persistent role after the fusion stage. In particular, a rotational damping in continuum is presented in calculations of both twist-averaged and absorbing boundary conditions, in which damping widths can be clearly extracted. It is unusual that the rotating compound nucleus in continuum evolves toward spherical but still has a considerable angular momentum.

The nuclear chiral conundrum with crossing twin bands is investigated with three-dimensional tilted axis cranking covariant density functional theory in a fully self-consistent and microscopic way. The energy spectra and electromagnetic transition strengths for bands 1 and 2 in ${}^{106}\mathrm{Ag}$ are well reproduced with two distinct configurations with two and four quasiparticles, respectively. For the four-quasiparticle configuration, a chiral vibrational band on top of band 2 is expected due to the soft Routhian curves. Therefore, it provides a microscopic and solid solution for the chiral conundrum in ${}^{106}\mathrm{Ag}$. It also paves the way for understanding similar chiral structure in other nuclei in the future.

A systematic study of total fusion involving the weakly bound nuclei ${}^{6,7}\mathrm{Li}$ with several light to heavy mass targets at Coulomb energies is presented. Emphasis is given to the role of resonance states ($l=2,J^{\pi }=3^{+},2^{+},1^{+}$ of ${}^6\mathrm{Li}$ and $l=3,J^{\pi }=7/2^{-},5/2^{-}$ of ${}^7\mathrm{Li}$) on the total fusion excitation function. A comparative analysis of the effects of resonant breakup on total fusion is performed for both projectiles, using the continuum-discretized coupled-channel (CDCC) framework. The calculations demonstrate that (i) resonant breakup couplings play a more important role in total fusion than nonresonant couplings, (ii) resonance states with short half-lives are very important for total fusion, as incident energies decrease toward the Coulomb barrier energy where incomplete fusion dominates, and (iii) resonance states with long half-life act as quasibound inelastic states, playing a crucial role in complete fusion.

A systematic study of system size, $N/Z$ asymmetry, and fragmenting volume effects as well as the Coulomb effect on experimental measures for the nuclear liquid-gas phase transition and the mechanism of phase transition are carried out in the framework of the statistical multifragmentation model (SMM). The measures examined here are the caloric curve, the specific heat capacity ($C_v$), the multiplicity derivative ($dM/dT$), the moment parameters ($M_2$ and ${\gamma }_2$), the fluctuation of maximum fragment charge number (NVZ), the Fisher exponent ($\tau$), and the Zipf's law parameter ($\xi$). A signal for the first-order phase transition for all the measures is observed. A stronger signal is observed in the system with smaller sizes or with more neutron rich or in smaller fragmenting volumes for the caloric curve, $C_v$, and $dM/dT$. The phase-transition temperatures are independent of the system size, $N/Z$ asymmetry, fragmenting volume, and Coulomb force, which indicates these measures give a solid signal for the liquid-gas phase transition in SMM. On the other hand, the phase transition temperature and its behavior of the others slightly depend on the size, the $N/Z$ asymmetry and the volume of the system. A negative heat capacity is observed for systems with $A_s\ge$ 100 without the Coulomb force but disappears with the Coulomb. An instructive picture is given in the charge distributions for the observed first-order phase transition.

We calculate the contribution of the $\left|\mathrm{\Delta }S\right|=1K$ meson exchange process generated by the Cabibbo–Kobayashi–Maskawa matrix to the electric-dipole moment (EDM) of the ${}^9\mathrm{Be}$ nucleus by considering the $\alpha n\text{−}\alpha \mathrm{\Lambda }$ channel coupling. It is found that the effect of the Pauli exclusion principle is not important intermediate $S=-1$ state, and that the result is consistent with the EDM of ${}^9\mathrm{Be}$ calculated with the $\left|\mathrm{\Delta }S\right|=1$ interactions as a perturbation without considering the nucleus-hypernucleus mixing. Our result suggests that the effect of the $\left|\mathrm{\Delta }S\right|=1$ interactions is neither suppressed nor enhanced in nuclei, if the difference of binding energies between the nucleus and the hypernucleus is small compared with the hyperon-nucleon mass difference.

I have used a potential model and a convolution procedure to compute energy-dependent widths for simultaneous ${}^{11}\mathrm{O}\left(\mathrm{g}.\mathrm{s}.\right)\to {}^9\mathrm{C}+2p$ decay. A Breit-Wigner shape calculated with those widths provides excellent agreement with recent experimental data.

The fission of even-even fermium nuclides ${}^{250-260}\mathrm{Fm}$ at low excitation energy was studied using Langevin equations of three-dimensional nuclear-shape parametrization. The mass distributions of fission fragments show a dramatic change from an asymmetric shape for the lighter fermium isotopes to sharp symmetric fission for the heavier isotopes. The time evolution of the nuclear shape on the potential surface reveals that the lighter fermium isotopes showing asymmetric fission are trapped in the second minimum for a substantial length of time before overcoming the second saddle point. This behavior changes dramatically for the compact symmetric fission found in the heavier neutron-rich fermium nuclei that disintegrate immediately after overcoming the first saddle point, without feeling the second barrier, resulting in a fission time two orders of magnitude shorter.