Photodisintegration of polarized ${}^3\mathrm{He}$ by linearly or circularly polarized photons offers a rich choice of observables, which can be calculated with high precision using a rigorous scheme of three-nucleon Faddeev equations. Using the (semi)phenomenological AV18 nucleon-nucleon potential combined with the Urbana IX three-nucleon force we investigate sensitivity of ${}^3\mathrm{He}$ photodisintegration observables to underlying currents taken in the form of a single-nucleon current supplemented by two-body contributions for $\pi$- and $\rho$-meson exchanges or incorporated by the Siegert theorem. Promising observables to be measured for two- and three-body fragmentation of ${}^3\mathrm{He}$ are identified. These observables form a challenging test ground for consistent forces and currents being under derivation within the framework of chiral perturbation theory. For three-body ${}^3\mathrm{He}$ photodisintegration several kinematicaly complete configurations, including SST and FSI, are also discussed.

Background: The nuclear level density (NLD) and photon strength functions (PSFs) are necessary quantities for calculating the interaction of photons with nuclei, in particular the reaction cross sections. As such, they are important especially in nuclear astrophysics and in the development of advanced nuclear technologies.

Purpose: The presence of a resonancelike structure in the $E1$ PSF at $\gamma$-ray energy of about 5.5 MeV was reported in $\gamma$-soft $A\approx 200$ nuclei from several experimental techniques. However, as data from different experiments are not fully consistent, additional information on PSFs in this region is of great interest. In addition, present PSF models have difficulties to describe resonancelike structures for energies below the neutron separation energy $S_n$. There are also open questions about the energy and parity dependence of the NLD.

Methods: The $\gamma$ rays following the radiative neutron capture on ${}^{195}\mathrm{Pt}s$-wave resonances were measured with the highly segmented $\gamma$-ray calorimeter Detector for Advanced Neutron Capture Experiments at the Los Alamos Neutron Science Center. The $\gamma$-ray energy spectra for different multiplicities were gathered for several resonances of both possible spins.

Results: The $\gamma$-ray energy spectra were analyzed within the statistical model and allowed us to get information about the NLD and PSFs in ${}^{196}\mathrm{Pt}$. Neither the PSFs from any previous experiment nor any available PSFs models are able to describe our spectra. We were able to find PSFs and NLD that reasonably describe experimental spectra and impose various restrictions on these quantities.

Conclusions: The presence of a resonancelike structure in the $E1$ PSF at a $\gamma$-ray energy of about 5.6 MeV is confirmed. The constant temperature energy dependence is favored for a NLD with a significant parity dependence up to an excitation energy of at least 4 MeV. The preferred $M1$ PSF shape is close to a Lorentzian tail of the spin-flip resonance.

The reactions of nucleons and polarized deuterons scattered off a heavy target nucleus at large impact parameter with intermediate energies have been investigated by using the improved quantum molecular dynamics model. It is found that, due to the opposite effects of isovector potential on protons and neutrons, there is a significant difference between the angle distributions of elastically scattered protons and neutrons. To overcome the lack of a monochromatic neutron beam, the reaction of polarized deuterons peripherally scattered off a heavy target nucleus is used to replace the reaction of individual protons and neutrons scattered off a heavy target nucleus to study the isospin effect. It is found that the distributions of the scattering angle of the proton and the neutron originating from the elastic breakup of the deuteron are very similar to the results of the individual proton- and neutron-induced reactions. A new probe more effective and more clean, namely the difference between the elastic scattering angle of the proton and that of the neutron originating from the breakup of the polarized deuteron, is promoted to constrain the symmetry energy at subsaturation density.

We report systematic measurements of bulk properties of the system created in $\mathrm{Au}+\mathrm{Au}$ collisions at $\sqrt{s_{NN}}=14.5$ GeV recorded by the STAR detector at the Relativistic Heavy Ion Collider (RHIC). The transverse momentum spectra of ${\pi }^{\pm }, K^{\pm }$, and $p\left(\overline{p}\right)$ are studied at midrapidity ($\left|y\right|<0.1$) for nine centrality intervals. The centrality, transverse momentum ($p_T$), and pseudorapidity ($\eta$) dependence of inclusive charged particle elliptic flow ($v_2$), and rapidity-odd charged particles directed flow ($v_1$) results near midrapidity are also presented. These measurements are compared with the published results from $\mathrm{Au}+\mathrm{Au}$ collisions at other energies, and from $\mathrm{Pb}+\mathrm{Pb}$ collisions at $\sqrt{s_{NN}}=2.76$ TeV. The results at $\sqrt{s_{NN}}=14.5$ GeV show similar behavior as established at other energies and fit well in the energy dependence trend. These results are important as the 14.5-GeV energy fills the gap in ${\mu }_B$, which is of the order of 100 MeV, between $\sqrt{s_{NN}}=11.5$ and 19.6 GeV. Comparisons of the data with UrQMD and AMPT models show poor agreement in general.

Based on the constituent quasiparticle model of quark-gluon plasma (QGP), the matrix elements of the density operator and the Wigner function in the color phase space are presented in form of color path integrals over Wiener and SU(3) group Haar measures. Monte Carlo calculations of quark and gluon momentum distributions and spatial pair distribution functions have been carried out for the strongly coupled QGP plasma in thermal equilibrium at zero baryon chemical potential. The Debye screening mass and the running coupling constant have been obtained from the spatial pair distribution function and are in agreement with the available lattice QCD data. At densities related to the average interparticle distance more than 0.4 fm the gluon bound states in the form of glue balls have been found. Comparison with the Maxwell-Boltzmann distribution shows significant influence of interparticle interaction on high-energy asymptotics of the momentum distribution functions, resulting in appearance of quantum tails. The new color pair correlation function has been introduced, and related new color screening mass has been discussed.

Measurements of atomic transitions in different isotopes offer key information on the nuclear charge radius. The anticipated high-precision experimental techniques, augmented by atomic calculations, will soon enable extraction of the higher order radial moments of the charge density distribution. To assess the value of such measurements for nuclear structure research, we study the information content of the fourth radial moment $\langle r^4\rangle$ by means of nuclear density functional theory and a multiple correlation analysis. We show that $\langle r^4\rangle$ can be directly related to the surface thickness of nuclear density, a fundamental property of the atomic nucleus that is difficult to obtain for radioactive systems. Precise knowledge of these radial moments is essential to establish reliable constraints on the existence of new forces from precision isotope shift measurements.

The event generator based on the higher-twist energy loss formalism—Modular All Twist Transverse-scattering Elastic-drag and Radiation (Matter)—is further developed and coupled to a hydrodynamic model for studying jet modification in relativistic nuclear collisions. The probability of parton splitting is calculated using the Sudakov form factor that is constructed by a combination of vacuum and medium-induced splitting functions; and the full parton showers are simulated, including both energy-momentum and space-time evolutions of all jet partons. With the assumption that partons below a virtual scale of 1 GeV is absorbed by the medium, this framework is able to provide a reasonable description of the nuclear modification of both leading hadrons and jets at high transverse momentum at the BNL Relativistic Heavy Ion Collider and the CERN Large Hadron Collider.

Multiplicity fluctuations are one of the most crucial observables in the Beam Energy Scan program of the Relativistic Heavy Ion Collider. It is understood that they can be utilized to probe the whereabouts of the critical point on the phase diagram of the QCD matter. However, a significant portion of these fluctuations is, apart from that related to the QCD phase transition, attributed to the other origins, which we refer to as “noncritical” ones. The present study is dedicated to the noncritical aspects of the multiplicity fluctuations in heavy-ion collisions. In particular, we focus on those of dynamical origin, such as the hydrodynamic expansion of the system and the event-by-event initial fluctuations, in addition to the usual thermal fluctuations, finite-volume corrections, and resonance decay at the freeze-out surface. The obtained results are compared to those of the hadronic resonance gas model as well as to the experimental data.

Inspired by the observations of three $P_c$ states, we systematically investigate interactions between an $S$-wave charmed baryon ${\mathcal{B}}_c^{(*)}={\mathrm{\Lambda }}_c/{\mathrm{\Sigma }}_c/{\mathrm{\Sigma }}_c^{*}$ and an anticharmed meson $\overline{T}={\overline{D}}_1/{\overline{D}}_2^{*}$ with the one-pion-exchange potential model and the one-boson-exchange potential model, and search for possible new types of $P_c$ states with the structures of ${\mathcal{B}}_c^{(*)}\overline{T}$. Both $S-D$ wave mixing and coupled channel effects are considered. Our results suggest that in some ${\mathcal{B}}_c^{(*)}\overline{T}$ systems there are ideal candidates of new types of $P_c$ states—i.e., the ${\mathrm{\Sigma }}_c{\overline{D}}_1$ state with $I\left(J^P\right)=1/2(1/2^{+})$, the ${\mathrm{\Sigma }}_c{\overline{D}}_2^{*}$ state with $I\left(J^P\right)=1/2(3/2^{+})$, the ${\mathrm{\Sigma }}_c^{*}{\overline{D}}_1$ state with $I\left(J^P\right)=1/2(1/2^{+})$, and the ${\mathrm{\Sigma }}_c^{*}{\overline{D}}_2^{*}$ states with $I\left(J^P\right)=1/2(1/2^{+},3/2^{+})$—and we suggest that these predicted new types of $P_c$ states can be detected in the process ${\mathrm{\Lambda }}_b^0\to \psi \left(2S\right)p{\pi }^{-}$. Meanwhile, we also extend our study to the interactions between an $S$-wave charmed baryon and a charmed meson in a $T$ doublet, and we predict a series of double-charm molecular pentaquarks.

The ${}^{22}\mathrm{Ne}(p,\gamma ){}^{23}\mathrm{Na}$ reaction in the Ne-Na cycle plays an important role in the production of the only stable sodium isotope ${}^{23}\mathrm{Na}$. This nucleus is processed by the Ne-Na cycle during hot bottom burning (HBB) in the asymptotic giant branch (AGB) stage of low metallicity intermediate mass stars $(4M_{\odot }\le M\le 6M_{\odot })$. Recent measurements have addressed the uncertainty in the thermonuclear reaction rate of this reaction at relevant astrophysical energies through the identification of low lying resonances at $E_p$ = 71, 105, 156.2, 189.5, and 259.7 keV. In addition, precise measurements of the low energy behavior of nonresonant capture have been performed and the contribution of the subthreshold resonance at 8664 keV excitation in ${}^{23}\mathrm{Na}$ has been established. Here we present a systematic $R$-matrix analysis of direct capture to the bound states and the decay of the subthreshold resonance at 8664 keV to the ground state of ${}^{23}\mathrm{Na}$. A finite-range distorted-wave Born approximation (FRDWBA) calculation has been performed for the ${}^{22}\mathrm{Ne}({}^3\mathrm{He},d){}^{23}\mathrm{Na}$ transfer reaction data to extract the asymptotic normalization coefficients (ANCs) required to estimate the nonresonant capture cross sections or astrophysical $S$-factor values in the $R$-matrix analysis. Simultaneous $R$-matrix analysis constrained with ANCs from transfer calculations reproduced the astrophysical $S$-factor data over a wide energy window. The value $S_{tot}^{DC}\left(0\right)=48.8\pm 9.5\mathrm{keV}\mathrm{b}$ compares well with the result of Ferraro et al. and has a lower uncertainty. The resultant thermonuclear reaction is slightly larger in the $0.1\le T\le 0.2$ GK temperature range but otherwise in agreement with Ferraro et al.

The time-dependent Faddeev equations (TDFEs) are employed for the first time as a computational tool for three-particle scattering problems. Rearrangement transition amplitudes over a wide range of collision energies are extracted from a single numerical wave-packet solution of the TDFE. To numerically solve the TDFE in momentum space for a given initial wave packet, finite-element-type discretizations of Jacobi momenta in terms of local basis functions is employed to convert the TDFE into a set of first-order differential equations in time. Central difference formula for the time derivative is used for the time propagation step. Two forms of TDFE are considered and incorporation of permutational symmetry for three identical particles into these equations is carried out. The proposed method is tested on a three-body model that is often used as a benchmark to compare different computational approaches to three-particle problem. Rearrangement $S$-matrix elements obtained from the analysis of the wave-packet solution of TDFE at asymptotic times are compared with the results of well-established time-independent methods. These results establish that the TDFE approach is a viable and competitive addition to the existing arsenal of computational methods for the three-body scattering problem.

New measurements of proton/deuteron elastic and inelastic scattering to the $2_1^{+}$ state of the neutron-rich nucleus ${}^{16}\mathrm{C}$ have been performed at Radioactive Ion Beam Line in Lanzhou (RIBLL) in inverse kinematics. The angular distributions of elastic scattering were well reproduced by the systematic optical potential with normalization factors for the depths of real and imaginary parts. The neutron and proton deformation lengths of ${\delta }_n=1.25\pm 0.30$ fm and ${\delta }_p=1.07\pm 0.26$ fm were extracted from the inelastic scattering data. The ratio of neutron and proton matrix element $M_n/M_p=1.95\pm 0.47$ was determined from the two different probes. Within error bar, this result is in fair agreement with the previous measurements, demonstrating that the combination of proton and deuteron inelastic scattering offers a useful method to extract $M_n/M_p$ for the even-even nuclei. Most of the theoretical predictions by the shell model using the MK, WBT, WBT*, and YSOX interactions in $p-sd$ model space and by the ab initio in-medium similarity renormalization group are close to these experimental results.

The exclusive breakup of the Borromean nucleus ${}^9\mathrm{Be}$ incident on a proton target at 5.67 MeV/nucleon was studied with a triple coincidence requirement between the two breakup $\alpha$ fragments and the recoiling proton. The analysis was performed using an event-by-event code in a full kinematics approach, and $Q$-value spectra, relative spectra, and energy spectra of all reaction products were determined. Clear signatures of the three breakup modes: $\alpha +\alpha +n, {}^8\mathrm{Be}+n$, and ${}^5\mathrm{He}+{}^4\mathrm{He}$ were observed in the recoiling proton spectra and the rates of these modes were quantified.

$\mathrm{\Lambda }N$ spin-spin and spin-orbit splittings in low-lying excitation spectra are investigated for $p$-shell $\mathrm{\Lambda }$ hypernuclei on the basis of the microscopic structure calculation within the antisymmetrized molecular dynamics, where the $\mathrm{\Lambda }NG$-matrix interaction derived from the baryon-baryon interaction model ESC (extended soft core) is used. It is found that the ground-state spin-parity is systematically reproduced in the $p$-shell $\mathrm{\Lambda }$ hypernuclei by tuning the $\mathrm{\Lambda }N$ spin-spin and spin-orbit interactions so as to reproduce the experimental data of ${}_{\mathrm{\Lambda }}{}^4\mathrm{H},{}_{\mathrm{\Lambda }}{}^7\mathrm{Li}$, and ${}_{\mathrm{\Lambda }}{}^9\mathrm{Be}$. Furthermore, we also focus on the excitation energies of the excited doublets as well as the energy shifts of them by the addition of a $\mathrm{\Lambda }$ particle.

We study the production of multicharmed hadrons by recombination in heavy ion collisions by focusing on the production of ${\mathrm{\Xi }}_{cc},{\mathrm{\Xi }}_{cc}^{*},{\mathrm{\Omega }}_{scc},{\mathrm{\Omega }}_{scc}^{*},{\mathrm{\Omega }}_{ccc}$ baryons and $X\left(3872\right)$ mesons. Starting from the estimation of yields for those hadrons at chemical freeze-out in both the statistical and coalescence models, we evaluate their transverse momentum distributions at midrapidity in the coalescence model. Considering the experimental measurements of weakly decaying singly charmed hadrons we find that yields of multicharmed hadrons in heavy ion collisions at RHIC and LHC are large enough, and thereby not only multicharmed hadrons observed so far, e.g., the ${\mathrm{\Xi }}_{cc}$, but also those which have not been observed yet, can be discovered in heavy ion collisions. We also find that the transverse momentum distribution ratio between various multicharmed hadrons sensitively reflects the interplay between quark contents of corresponding hadrons as well as the transverse momentum distribution of charm quarks at the hadronization point, and therefore we insist that studying both the transverse momentum distributions of multicharmed hadrons themselves and transverse momentum distribution ratios between various multicharmed hadrons provide us with useful information on hadron production mechanism involving charm quarks in heavy ion collisions.

Estimates for elliptic flow in collisions of polarized light nuclei with spin $j\ge 1$ with a heavy nucleus are presented. In such collisions, the azimuthal symmetry is broken via polarization of the wave function of the light nucleus, resulting in a nonzero one-body elliptic flow coefficient evaluated relative to the polarization axis. For the case of the deuteron we carry out the Glauber Monte Carlo simulations of the initial state followed with hydrodynamics to obtain the elliptic flow coefficient. A careful statistical error analysis is presented, showing that the effect could be easily spotted in future experiments with data samples of sizes as low as $\approx {10}^4$. We also present estimates of the effect for collisions with other light $j\ge 1$ nuclei, involving experimentally well-known features, such as their quadrupole moments and the charge radii. We find the one-body elliptic flow coefficient in the range from $\approx 0.5$% for collisions with a deuteron to $\approx 5\%$ for collisions with a ${}^{10}\mathrm{B}$ nucleus, with the relative error being small for typical data sample multiplicities. Prospects of addressing the issue in the upcoming fixed-target experiments at the CERN Large Hadron Collider are discussed.

Isotopic studies of meteorites have provided ample evidence for the presence of short-lived radionuclides (SLRs) with half-lives of less than 100 Myr at the time of the formation of the solar system. The origins of all known SLRs are heavily debated and remain uncertain, but the plausible scenarios can be broadly separated into either local production or outside injection of stellar nucleosynthesis products. The SLR production models are limited in part by reliance on nuclear theory for modeling reactions that lack experimental measurements. Reducing uncertainty on critical reaction cross sections can both enable more precise predictions and provide constraints on physical processes and environments in the early solar system. This goal led to the start of a campaign for measuring production cross sections for the SLR ${}^{36}\mathrm{Cl}$, where Bowers et al. found higher cross sections for the ${}^{33}\mathrm{S}(\alpha ,p){}^{36}\mathrm{Cl}$ reaction than were predicted by Hauser-Feshbach based nuclear reaction codes talys and non-smoker. This prompted re-measurement of the reaction at five new energies within the energy range originally studied, resulting in data slightly above but in agreement with talys. Following this, efforts began to measure cross sections for the next most significant reaction for ${}^{36}\mathrm{Cl}$ production, ${}^{34}\mathrm{S}({}^3\mathrm{He},p){}^{36}\mathrm{Cl}$. Activations were performed to produce nine samples between 1.11 MeV/nucleon and 2.36 MeV/nucleon. These samples were subsequently measured with accelerator mass spectrometry at two labs. The resulting data suggest a sharper-than-expected rise in cross sections with energy, with peak cross sections up to 30% higher than predictions from talys.

The effects of possible noncollective pairs in even-even${}^{124\text{–}128}\mathrm{Sn}$ are studied in the nucleon-pair shell model, in which a few noncollective neutron pairs originating from the alignment of two neutrons in the $\nu h_{11/2}$ orbit are considered. From the low-lying-level energies, $B\left(E2\right)$ ratios, and excited states obtained from the model, it is shown that the yrast band structure can be explained as the evolution from vibrational to rotational type as a function of spin. The mechanism of the yrast band can be explained as band crossing between the ground-state band and the $S$ band constructed from the neutron alignment in the $\nu h_{11/2}$ orbit. The noncollective configurations may be crucial for describing the yrast states in even-even${}^{124,126,128}\mathrm{Sn}$ in the $SD$-pair shell model.