The fission decay probabilities of the ${}^{235}\mathrm{Pa}$ and ${}^{236}\mathrm{U}$ compound nuclei produced in a single experiment in ${}^{232}\mathrm{Th}$(${}^7\mathrm{Li}$, $\alpha f$)${}^{235}\mathrm{Pa}$ and ${}^{232}\mathrm{Th}$(${}^7\mathrm{Li}$, $tf$)${}^{236}\mathrm{U}$ transfer induced fission reaction channels, have been measured at $E_{\mathrm{lab}}=39.5$ MeV in the excitation energy range of 14–20 MeV. The ${}^{234}\mathrm{Pa}$(n, f) cross sections are then deduced from the measured fission decay probability ratios of ${}^{235}\mathrm{Pa}$ and ${}^{236}\mathrm{U}$ compound systems in the equivalent neutron energy range of 8–14 MeV within the framework of the hybrid surrogate ratio method, considering the well-measured ${}^{235}\mathrm{U}$(n, f) cross sections as the reference. The experimental data on ${}^{234}\mathrm{Pa}$(n, f) cross sections have been compared with the calculated fission cross sections using empire-3.1 code with the fission barrier height values obtained from barrier formula (BF) as well as ripl-3 [24]. The present experimental results are found to be in very good agreement with the empire-3.1 predictions for the fission barrier heights predicted by the BF.

Fusion and quasi-elastic scattering measurements have been carried out for ${}^{6,7}\mathrm{Li}$+${}^{197}\mathrm{Au}$ systems in the energy range $E/V_b\sim 0.7$ to 1.5. Coupled-channel calculations including coupling to inelastic states of the target and projectiles are able to explain an enhancement in measured fusion cross sections at energies below the barrier. At energies above the barrier the complete fusion cross sections are found to be suppressed compared to the coupled-channel predictions for both systems. A systematic comparison of fusion cross sections of the weakly bound stable nuclei ${}^{6,7}\mathrm{Li}$ and halo nuclei ${}^{6,8}\mathrm{He}$ on a ${}^{197}\mathrm{Au}$ target is presented. Barrier distributions from quasi-elastic scattering are seen to shift towards higher energies with respect to fusion after inclusion of the breakup-$\alpha$ channel for both ${}^6\mathrm{Li}$ and ${}^7\mathrm{Li}$.

By assuming that only gravitation acts between dark matter (DM) and normal matter (NM), we study the effects of fermionic DM on the properties of neutron stars using the two-fluid Tolman-Oppenheimer-Volkoff formalism. It is found that the mass-radius relationship of the DM admixed neutron stars (DANSs) depends sensitively on the mass of DM candidates, the amount of DM, and interactions among DM candidates. The existence of DM in DANSs results in a spread of mass-radius relationships that cannot be interpreted with a unique equilibrium sequence. In some cases, the DM distribution can surpass the NM distribution to form a DM halo. In particular, it is favorable to form an explicit DM halo, provided the repulsion of DM exists. It is interesting to find that the difference in particle number density distributions in DANSs and consequently in star radii caused by various density dependencies of nuclear symmetry energy tends to disappear as long as the repulsion of accumulated DM is sufficient. These phenomena indicate that the admixture of DM in neutron stars can significantly affect the astrophysical extraction of nuclear EOS by virtue of neutron star measurements. In addition, the effect of the DM admixture on the star maximum mass is also investigated.

The internal-conversion and internal-pair-production decays of the first excited 0${}^{+}$ state in ${}^{68}\mathrm{Ni}$ are studied following the $\beta$ decay of ${}^{68}\mathrm{Co}$. A novel experimental technique, in which the ions of ${}^{68}\mathrm{Co}$ were implanted into a planar germanium double-sided strip detector and which required digital pulse processing, is developed. The values for the energy of the first excited 0${}^{+}$ state and the electric monopole transition strength from the first excited 0${}^{+}$ state to the ground state in ${}^{68}\mathrm{Ni}$ are determined to be 1605(3) keV and $7.6\left(4\right)\times {10}^{-3}$, respectively. Comparisons of the experimental results to Monte Carlo shell-model calculations suggest the coexistence between a spherical ground state and an oblate first excited 0${}^{+}$ state in ${}^{68}\mathrm{Ni}$.

The first measurement of the three-body photodisintegration of polarized ${}^3\mathrm{He}$ using a circularly polarized photon beam has been performed at incident energies of 12.8 and 14.7 MeV. This measurement was carried out at the high-intensity $\gamma$-ray source located at Triangle Universities Nuclear Laboratory. A high-pressure ${}^3\mathrm{He}$ target, polarized via spin exchange optical pumping with alkali metals, was used in the experiment. The spin-dependent double- and single-differential cross sections from $\overrightarrow{{}^3\text{He}}(\vec{\gamma },n)pp$ for laboratory angles varying from ${30}^{\circ }$ to ${165}^{\circ }$ are presented and compared with state-of-the-art three-body calculations. The data reveal the importance of including the Coulomb interaction between protons in the three-body calculations.

Background: Resonances around $x\alpha$ thresholds in light nuclei are recognized to be important in basic aspects of nuclear structure. However, there is scarce experimental information associated with them.

Purpose: We study the $\alpha$-clustering phenomenon in resonant states around the $4\alpha$ threshold (14.44 MeV) in the ${}^{16}\text{O}$ nucleus.

Method: The ${}^{12}\text{C}{(}^6\text{Li},d){}^{16}\mathrm{O}$ reaction was investigated with an unprecedented resolution at a bombarding energy of 25.5 MeV by employing the São Paulo Pelletron-Enge-Spectrograph facility and the nuclear emulsion technique.

Results: Several narrow resonances were populated and the energy resolution of 15 keV allows for the separation of doublet states that were not resolved previously. The upper limits for the resonance widths in this region were extracted. The angular distributions of the absolute differential cross section associated with four natural parity quasibound states are presented and compared to distorted wave Born approximation predictions.

Conclusions: Narrow resonances not previously reported in the literature were observed. This indicates that the $\alpha$-cluster structure information in this region should be revised.

The neutron-deficient mercury isotopes, ${}^{184,186}\mathrm{Hg}$, were studied with the recoil distance Doppler-shift method using the Gammasphere array and the Köln plunger device. The differential decay curve method was employed to determine the lifetimes of the yrast states in ${}^{184,186}\mathrm{Hg}$. An improvement on previously measured values of yrast states up to $8^{+}$ is presented as well as first values for the $9_3$ state in ${}^{184}\mathrm{Hg}$ and ${10}^{+}$ state in ${}^{186}\mathrm{Hg}$. $B\left(E2\right)$ values are calculated and compared to a two-state mixing model which utilizes the variable moment of inertia model, allowing for extraction of spin-dependent mixing strengths and amplitudes.

Neutron emission in the fusion process is investigated based on the Langevin equations coupled with the procedures describing the emission of neutron for the reaction systems ${}^{48}\mathrm{Ca}$ + ${}^{238}U$ and ${}^{50}\mathrm{Ti}$ + ${}^{249}\mathrm{Cf}$. The precompound neutron multiplicity $n_{pc}$, defined as the average number of neutron per fusion event, is obtained by means of those dynamic calculations. Influence of precompound neutron emission on the formation of superheavy elements is examined by means of the dynamic calculations using two different approaches, i.e., with and without taking the neutron emission into account in the fusion process. Our results show that the precompound neutron emission enhances the formation cross sections of superheavy nuclei. The origin responsible for the enhancement is that the precompound neutron emission increases the survival probability of the evaporation residue and hence increases the relevant cross sections.

A formalism is presented for the investigation of the reaction $ed\to e^{\prime }{K}^{+}\Lambda n$ in the relativistic impulse approximation. The formalism is based on a tree-level, effective Lagrangian model for the underlying virtual photoproduction reaction amplitude which incorporates a variety of baryon resonances with spins up to $\frac{5}{2}$ and the two kaon resonances, $K^{☆}\left(892\right)$ and $K1\left(1270\right)$. The parameters of the model were fit to a large pool of proton photoproduction data from the CLAS, GRAAL, SAPHIR, and LEPS Collaborations and to CLAS data for the virtual photoproduction structure functions ${\sigma }_U$, ${\sigma }_T$, ${\sigma }_L$, ${\sigma }_{TT}$, ${\sigma }_{LT}$, and ${\sigma }_{L{T}^{\prime }}$. The final-state $\Lambda n$ interaction is incorporated in the model by means of a three-dimensional overlap integral based on a simple phenomenological $\Lambda n$ potential. Results are presented for both the differential cross section, $d\sigma /d{\Omega }_K$, and the double differential cross section, $d\sigma /d{\Omega }_{K}d{E}_K$, for the virtual photoproduction of positive kaons and $\Lambda$'s from the deuteron.

We investigate the factorization properties of the exclusive electroinduced two-nucleon knockout reaction $A(e,e^{\prime }pN)$. A factorized expression for the cross section is derived and the conditions for factorization are studied. The $A(e,e^{\prime }pN)$ cross section is shown to be proportional to the conditional center-of-mass (c.m.) momentum distribution for close-proximity pairs in a state with zero relative orbital momentum and zero radial quantum number. The width of this conditional c.m. momentum distribution is larger than the one corresponding with the full c.m. momentum distribution. It is shown that the final-state interactions (FSIs) only moderately affect the shape of the factorization function for the $A(e,e^{\prime }pN)$ cross sections. Another prediction of the proposed factorization is that the mass dependence of the $A(e,e^{\prime }pp)$ $\left[A(e,e^{\prime }pn)\right]$ cross sections is much softer than $\frac{Z(Z-1)}{2}$ $\left[NZ\right]$.

I consider particle production in high-energy $pA$ collisions. In addition to the coherent interactions with the nuclear color field, I take into account coherent interactions with the nuclear electromagnetic Coulomb field. Employing the dipole model, I sum up the leading multiple color and electromagnetic interactions and derive inclusive cross sections for photon and dilepton production. I found that the Coulomb corrections are up to 10% at $\sqrt{s}=200$ GeV per nucleon.

We study the dynamics of charm quarks in the partonic medium and its implication for the di-electron spectra in high-energy heavy ion collisions. The charm quarks traversing a thermal medium are simulated by the relativistic Langevin equation for elastic scattering of charm quarks by thermal partons in an expanding fireball. The transport coefficients of the charm quarks are calculated by the in-medium $T$-matrix method, where a static heavy quark potential is used with parameters fitted by the lattice QCD results. The di-electron invariant mass spectra are computed in the most central collisions and are compared to the STAR data. The angular correlations of di-electrons are almost the same in $p+p$ and $\text{Au}+\text{Au}$ collisions in the mass range $1.1<M<2.5\mathrm{GeV}/c^2$ with a back-to-back feature. This means that the angular correlation is intact even with medium interaction at the energy of the Relativistic Heavy Ion Collider.

The reaction mechanisms of the two-neutron transfer reaction ${}^{12}$C(${}^6$He,${}^4$He) have been studied at $E_{\mathrm{lab}}=30$ MeV at the TRIUMF ISAC-II facility using the Silicon Highly-segmented Array for Reactions and Coulex (SHARC) charged-particle detector array. Optical potential parameters have been extracted from the analysis of the elastic scattering angular distribution. The new potential has been applied to the study of the transfer angular distribution to the 2${}_2^{+}$ 8.32 MeV state in ${}^{14}$C, using a realistic three-body ${}^6$He model and advanced shell-model calculations for the carbon structure, allowing to calculate the relative contributions of the simultaneous and sequential two-neutron transfer. The reaction model provides a good description of the 30-MeV data set and shows that the simultaneous process is the dominant transfer mechanism. Sensitivity tests of optical potential parameters show that the final results can be considerably affected by the choice of optical potentials. A reanalysis of data measured previously at $E_{\mathrm{lab}}=18$ MeV, however, is not as well described by the same reaction model, suggesting that one needs to include higher-order effects in the reaction mechanism.

Transverse-mass spectra, their inverse slopes, and mean transverse masses in relativistic collisions of heavy nuclei are analyzed in a wide range of incident energies, 2.7 GeV $\le \sqrt{s_{NN}}\le$ 39 GeV. The analysis is performed within the three-fluid model, employing three different equations of state (EoS): a purely hadronic EoS, an EoS with the first-order phase transition, and an EoS with a smooth crossover transition into deconfined state. Calculations show that inverse slopes and mean transverse masses of all the species (with the exception of antibaryons within the hadronic scenario) exhibit steplike behavior similar to that observed for mesons and protons in available experimental data. This steplike behavior takes place for all considered EoSs and results from the freeze-out dynamics rather than being a signal of the deconfinement transition. A good reproduction of experimental inverse slopes and mean transverse masses for light species (up to protons) is achieved within all the considered scenarios. The freeze-out parameters are precisely the same as those used for reproduction of particle yields in previous papers of this series. This became possible because the freeze-out stage is not completely equilibrium.

High spin states of ${}^{34}\text{Cl}$ populated through ${}^{27}\text{Al}$(${}^{12}\text{C}$,$\alpha n$)${}^{34}\text{Cl}$ reaction at $E{(}^{12}\text{C})=40$ MeV, have been studied using the Indian National Gamma Array facility. The level scheme has been extended up to 10.6 MeV utilizing the results of intensity, directional correlation, and linear polarization measurements. Lifetimes of a few excited states have been estimated for the first time using the Doppler shift attenuation method. Large-basis shell-model calculations within the $sd\text{−}pf$ space have been done to understand the microscopic origin of the excited states. Involvement of $pf$ orbitals have been found to be essential to reproduce the negative-parity as well as high spin positive-parity states. Onset of collectivity manifested through short half-lives and large $B\left(E2\right)$ values have been reproduced well in the calculations.

Masses of superheavy (SH) nuclei with $Z=98–128$, including odd and odd-odd nuclei, are systematically calculated within the microscopic-macroscopic model based on the deformed Woods-Saxon potential. Ground states are found by minimizing energy over deformations and configurations. Pairing in odd particle-number systems is treated either by blocking or by adding the BCS energy of the odd quasiparticle. Three new parameters are introduced which may be interpreted as the constant mean pairing energies for even-odd, odd-even, and odd-odd nuclei. They are adjusted by a fit to masses of heavy nuclei. Other parameters of the model, fixed previously by fitting masses of even-even heavy nuclei, are kept unchanged. With this adjustment, the masses of SH nuclei are predicted and then used to calculate $\alpha$-decay energies to be compared to known measured values. It turns out that the agreement between calculated $Q_{\alpha }$ values with data in SH nuclei is better than in the region of the mass fit. The model overestimates $Q_{\alpha }$ for $Z=111–113$. Ground state (g.s.) configurations in some SH nuclei hint to a possible $\alpha$-decay hindrance. The calculated configuration-preserving transition energies show that in some cases this might explain discrepancies, but more data are needed to explain the situation.

We compute transverse-momentum and momentum-integrated multiplicity distributions consistently in the IP-Glasma model for proton-proton and proton-lead collisions at the CERN Large Hadron Collider (LHC), in deuteron-gold collisions at the BNL Relativistic Heavy Ion Collider (RHIC), and in heavy-ion collisions at both RHIC and LHC energies. Several sources of subnucleon-scale contributions to the multiplicity distributions are identified. Our results, which are constrained by inclusive and diffractive deeply inelastic scattering data from the Hadron-Electron Ring Accelerator at DESY, are compared to measured distributions for a range of collision energies. These results are an essential first step in quantifying the relative role of initial- and final-state effects on multiparticle correlations in light- and heavy-ion collisions.

Within a multiphase transport model, medium modifications of differential jet shapes are investigated in $\text{Pb}+\text{Pb}$ collisions at $\sqrt{s_{{}_{\mathrm{NN}}}}$ = 2.76 TeV. The differential jet shapes are significantly modified by the strong interactions between jets and a partonic medium in $\text{Pb}+\text{Pb}$ collisions relative to that in $p+p$ collisions. The modifications are slightly weakened by the hadronization of coalescence, but strengthened by resonance decays in hadronic rescatterings. Subleading jets display larger medium modifications than leading jets, especially in central $\text{Pb}+\text{Pb}$ collisions with large dijet asymmetries. These behaviors of medium modifications of differential jet shapes reflect a dynamical evolution of redistribution of jet energy inside a quenched jet cone in high-energy heavy-ion collisions.

We extend the quark mean-field (QMF) model to strangeness freedom to study the properties of hyperons ($\Lambda ,\Sigma ,\Xi$) in infinite baryon matter and neutron star properties. The baryon-scalar meson couplings in the QMF model are determined self-consistently from the quark level, where the quark confinement is taken into account in terms of a scalar-vector harmonic oscillator potential. The strength of such confinement potential for $u,d$ quarks is constrained by the properties of finite nuclei, while that for an $s$ quark is limited by the properties of nuclei with a $\Lambda$ hyperon. These two strengths are not the same, which represents the SU(3) symmetry breaking effectively in the QMF model. Also, we use an enhanced $\Sigma$ coupling with the vector meson, and both $\Sigma$ and $\Xi$ hyperon potentials can be properly described in the model. The effects of the SU(3) symmetry breaking on the neutron star structures are then studied. We find that the SU(3) breaking shifts the hyperon onset density earlier and makes hyperons more abundant in the star, in comparison with the results of the SU(3) symmetry case. However, it has little effect on the star's maximum mass. The maximum masses are found to be $1.62M_{\odot }$ with hyperons and $1.88M_{\odot }$ without hyperons. The present neutron star model is shown to have limitations in explaining the recently measured heavy pulsars around $2M_{\odot }$.