A study of photofission on ${}^{181}\mathrm{Ta}$ induced by bremsstrahlung with endpoint energies of 50 and 3500 MeV has been performed. The fission yields have been measured by using the induced-activity method in an off-line analysis. The total photofission yields for the tantalum target at 50 and 3500 MeV are found to be $5.4\pm 1.1 \mu \mathrm{b}$/ equivalent quanta per second (eq.q) and $0.77\pm 0.11$ mb/eq.q, respectively, and the corresponding deduced fissilities are $\left(0.23\pm 0.05\right)\times {10}^{-3}$ and $\left(2.9\pm 0.5\right)\times {10}^{-3}$. Mass- and charge-yield distributions were derived from the data. The results were compared with the simulated results from the crisp code for multimodal fission by the assuming symmetrical fission mode.

By employing a Chapman-Enskog like iterative solution of the Boltzmann equation in relaxation-time approximation, we derive a new expression for the entropy four-current up to third order in gradient expansion. We show that unlike second-order and third-order entropy four-current obtained using Grad's method, there is a nonvanishing entropy flux in the present third-order expression. We further quantify the effect of the higher-order entropy density in the case of boost-invariant one-dimensional longitudinal expansion of a system. We demonstrate that the results obtained using the third-order evolution equation for the shear stress tensor, derived by employing the method of Chapman-Enskog expansion, show better agreement with the exact solution of the Boltzmann equation as well as with the parton cascade bamps, as compared to those obtained using the third-order equations from the method of Grad's 14-moment approximation.

We construct a coordinate-space chiral potential, including $\Delta$-isobar intermediate states in its two-pion-exchange component up to order $Q^3$ ($Q$ denotes generically the low momentum scale). The contact interactions entering at next-to-leading and next-to-next-to-next-to-leading orders ($Q^2$ and $Q^4$, respectively) are rearranged by Fierz transformations to yield terms at most quadratic in the relative momentum operator of the two nucleons. The low-energy constants multiplying these contact interactions are fitted to the 2013 Granada database, consisting of $2309 pp$ and $2982 np$ data (including, respectively, 148 and 218 normalizations) in the laboratory-energy range 0–300 MeV. For the total $5291 pp$ and $np$ data in this range, we obtain a ${\chi }^2/\mathrm{datum}$ of roughly 1.3 for a set of three models characterized by long- and short-range cutoffs, $R_{\mathrm{L}}$ and $R_{\mathrm{S}}$, respectively, ranging from $(R_{\mathrm{L}},R_{\mathrm{S}})=(1.2,0.8)$ fm down to $(0.8,0.6)$ fm. The long-range (short-range) cutoff regularizes the one- and two-pion exchange (contact) part of the potential.

The transverse-momentum-integrated elliptic flow of charged particles at midrapidity, $v_2$(charged), and that of identified hadrons from $\mathrm{Au}+\mathrm{Au}$ collisions are computed in a wide range of incident energies $2.7 \le \sqrt{s_{NN}}\le 39$ GeV. The simulations are performed within a three-fluid model by employing three different equations of state (EoSs): a purely hadronic EoS and two versions of the EoS involving the deconfinement transition—a first-order phase transition and a smooth crossover one. The present simulations demonstrate low sensitivity of $v_2$(charged) to the EoS. All considered scenarios equally well reproduce recent STAR data on $v_2$(charged) for mid-central $\mathrm{Au}+\mathrm{Au}$ collisions and properly describe its change of sign at the incident energy decrease below $\sqrt{s_{NN}}\approx 3.5$ GeV. The predicted integrated elliptic flow of various species exhibits a stronger dependence on the EoS. A noticeable sensitivity to the EoS is found for antibaryons and, to a lesser extent, for $K^{-}$ mesons. In particular, the $v_2$ excitation functions of antibaryons exhibit a nonmonotonicity within the deconfinement scenarios that was predicted by Kolb, Sollfrank, and Heinz. However, low multiplicities of antibaryons at $\sqrt{s_{NN}}\le 10$ GeV result in large fluctuations of their $v_2$, which may wash out this nonmonotonicity.

Analysis of directed flow $\left(v_1\right)$ of protons, antiprotons, and pions in heavy-ion collisions is performed in the range of incident energies $\sqrt{s_{NN}}=2.7–27$ GeV. Simulations have been done within a three-fluid model employing a purely hadronic equation of state (EoS) and two versions of the EoS involving deconfinement transitions: a first-order phase transition and a smooth crossover transition. High sensitivity of the directed flow, especially the proton one, to the EoS is found. The crossover EoS is favored by the most part of considered experimental data. A strong wiggle in the excitation function of the proton $v_1$ slope at the midrapidity obtained with the first-order-phase-transition EoS and a smooth proton $v_1$ with positive midrapidity slope, within the hadronic EoS unambiguously disagree with the data. The pion and antiproton $v_1$ also definitely testify in favor of the crossover EoS. The results obtained with deconfinement EoS's apparently indicate that these EoS's in the quark-gluon sector should be stiffer at high baryon densities than those used in the calculation.

The dynamic mechanism of the Thomas-Ehrman shift in three-cluster systems is studied by using the example of ${}^{16}\mathrm{Ne}$ and ${}^{16}\mathrm{C}$ isobaric mirror partners. We predict configuration mixings for $0^{+}$ and $2^{+}$ states in ${}^{16}\mathrm{Ne}$ and ${}^{16}\mathrm{C}$. Large isospin symmetry breaking on the level of wave function component weights is demonstrated for these states and discussed as a three-body mechanism of the Thomas-Ehrman shift. It is shown that the description of the Coulomb displacement energies requires consistency among three parameters: the ${}^{16}\mathrm{Ne}$ decay energy $E_T$, the ${}^{15}\mathrm{F}$ ground-state energy $E_r$, and the configuration mixing parameters for the ${}^{16}\mathrm{Ne}$ and ${}^{16}\mathrm{C}{0}^{+}$ and $2^{+}$ states. Based on this analysis we infer the ${}^{15}\mathrm{F}1/2^{+}$ ground-state energy to be $E_r=1.39\text{–}1.42$ MeV.

We present an ab initio symmetry-adapted no-core shell-model description for ${}^6\mathrm{Li}$. We study the structure of the ground state of ${}^6\mathrm{Li}$ and the impact of the symmetry-guided space selection on the charge density components for this state in momentum space, including the effect of higher shells. We accomplish this by investigating the electron scattering charge form factor for momentum transfers up to $q\sim 4{\mathrm{fm}}^{-1}$. We demonstrate that this symmetry-adapted framework can achieve significantly reduced dimensions for equivalent large shell-model spaces while retaining the accuracy of the form factor for any momentum transfer. These new results confirm the previous outcomes for selected spectroscopy observables in light nuclei, such as binding energies, excitation energies, electromagnetic moments, $E2$ and $M1$ reduced transition probabilities, as well as point-nucleon matter rms radii.

The coupled-channel theory is a natural way of treating nonelastic channels, in particular those arising from collective excitations characterized by nuclear deformations. A proper treatment of such excitations is often essential to the accurate description of experimental nuclear-reaction data and to the prediction of a wide variety of scattering observables. Stimulated by recent work substantiating the near validity of the adiabatic approximation in coupled-channel calculations for scattering on statically deformed nuclei, we explore the possibility of generalizing a global spherical optical model potential to make it usable in coupled-channel calculations on this class of nuclei. To do this, we have deformed the Koning-Delaroche global spherical potential for neutrons, coupling a sufficient number of states of the ground-state band to ensure convergence. We present an extensive study of the effects of collective couplings and nuclear deformations on integrated cross sections as well as on angular distributions for neutron-induced reactions on statically deformed nuclei in the rare-earth region. We choose isotopes of three rare-earth elements (Gd, Ho, W), which are known to be nearly perfect rotors, to exemplify the results of the proposed method. Predictions from our model for total, elastic, and inelastic cross sections, as well as for elastic and inelastic angular distributions, are in reasonable agreement with measured experimental data. These results suggest that the deformed Koning-Delaroche potential provides a useful regional neutron optical potential for the statically deformed rare-earth nuclei.

We demonstrate the validity of the complex scaling method for realistic strong, nonlocal, nucleon-nucleon interactions by comparing the deuteron bound state and nucleon-nucleon scattering phase shifts with results from other high-precision methods. This opens a pathway for the simultaneous ab initio solutions of the nuclear bound and scattering problems within a unified framework.

$2^{+}$ and $1^{-}$ states in ${}^{90}\mathrm{Zr}$ were populated via the $\left({}^{17}\mathrm{O},{}^{17}\mathrm{O}^{\prime }\gamma \right)$ reaction at 340 MeV. The $\gamma$ decay was measured with high resolution using the AGATA (advanced $\gamma$ tracking array demonstrator array). Differential cross sections were obtained at few different angles for the scattered particle. The results of the elastic scattering and inelastic excitation of $2^{+},3^{-}$, and $1^{-}$ states are compared with distorted-wave Born approximation (DWBA) calculations, using both the standard collective form factor and a form factor obtained by folding microscopically calculated transition densities. This allowed to extract the isoscalar component of the $1^{-}$ state at 6.424 MeV. The comparison of the present $\left({}^{17}\mathrm{O},{}^{17}\mathrm{O}^{\prime }\gamma \right)$ data with existing $\left(\gamma ,{\gamma }^{\prime }\right)$ and $\left(p,p^{\prime }\right)$ data in the corresponding region of the $\gamma$ continuum (6–11 MeV), characterized by a large $E1$ component, shows completely different behaviors of the cross section as a function of the nuclear excitation energy. The comparison of the data with DWBA calculations suggests a decrease of the isoscalar strength in the cross section with increasing excitation energy.

The excited states of ${}^{201}\mathrm{At}$ were studied and an isomeric $29/2^{+}$ state $[T_{½}=3.39\left(9\right)\mu \mathrm{s}]$ was identified by using a fusion-evaporation reaction, a gas-filled recoil separator, and recoil gating techniques. The $29/2^{+}$ state is suggested to originate from the $\pi \left(h_{9/2}\right)\otimes |{}^{200}\mathrm{Po};{11}^{-}\rangle$ configuration, and it decays through the 269- and 339-keV $E2$- and $E3$-type transitions, respectively. Moreover, a cascade of magnetic dipole transitions that is suggested to originate from a shears band was observed by using recoil-gated $\gamma -\gamma (-\gamma )$ coincidence techniques.

Excitation functions were measured by stacked-foil activation technique for the ${}^{150}\mathrm{Nd}(p,xpyn)$ reaction using a 97.65% enriched ${}^{150}\mathrm{Nd}$ target. Measurement up to $\sim 50\%$ above barrier and down to 18% below the barrier was performed using a proton beam energy $\left(E_p\right)$ of 7–15 MeV from the VECC Cyclotron. The yield of suitable $\gamma$ rays emitted following the decay of relevant evaporation residues was determined using a 50% high-purity germanium (HPGe) detector. The $(p,n)$ cross section was found to follow the expected trend with a maximum value of 63.7(4.9) mb at $E_p\sim 8.6$ MeV. The $(p,2n)$ cross section gradually increased with $E_p$ and had a maximum contribution to the total reaction cross section after $E_p\sim 9.0$ MeV. The ${(p,p}^{\prime }n)$ reaction channel also showed a reasonable yield with a threshold of $E_p\sim 12.0$ MeV. The experimental data were corroborated with statistical model calculations using different codes, viz., cascade, alice/91, and empire3.1. All the calculations using a suitable set of global parameters could reproduce the excitation function fairly well in the present energy range.

We utilize the parton cascade model to study the evolution of charm quarks propagating through a thermal brick of QCD matter. We determine the energy loss and the transport coefficient $\widehat{q}$ for charm quarks. The calculations are done at a constant temperature of 350 MeV and the results are compared to analytical calculations of heavy-quark energy loss in order to validate the applicability of using a parton cascade model for the study of heavy-quark dynamics in hot and dense QCD matter.

Measurements of bottomonium production in heavy-ion and $p+p$ collisions at the Relativistic Heavy Ion Collider (RHIC) are presented. The inclusive yield of the three ${\rm Y}$ states, ${\rm Y}(1S+2S+3S)$, was measured in the PHENIX experiment via electron-positron decay pairs at midrapidity for $\mathrm{Au}+\mathrm{Au}$ and $p+p$ collisions at $\sqrt{s_{\mathit{NN}}}=200$ GeV. The ${\rm Y}(1S+2S+3S)\to e^{+}{e}^{-}$ differential cross section at midrapidity was found to be $B_{\mathrm{ee}}d\sigma /dy=108\pm 38\left(\text{stat}\right)\pm 15\left(\text{syst}\right)\pm 11\left(\text{luminosity}\right)$ pb in $p+p$ collisions. The nuclear modification factor in the 30% most central $\mathrm{Au}+\mathrm{Au}$ collisions indicates a suppression of the total ${\rm Y}$ state yield relative to the extrapolation from $p+p$ collision data. The suppression is consistent with measurements made by STAR at RHIC and at higher energies by the CMS experiment at the Large Hadron Collider.

Cross sections for ${\pi }^{\pm }p$ elastic scattering have been measured to high precision by the EPECUR Collaboration for beam momenta between 800 and 1240 MeV/$c$ using the ITEP proton synchrotron. The data precision allows comparisons of the existing partial-wave analyses on a level not possible previously. These comparisons imply that over the covered energy range, the Carnegie-Mellon-Berkeley analysis is significantly more predictive when compared to versions of the Karlsruhe-Helsinki analyses.

We report the first global study of dynamic correlation energies (DCEs) associated with rotational motion and quadrupole shape vibrational motion in a covariant energy density functional (CEDF) for 575 even-even nuclei with proton numbers ranging from $Z=8$ to $Z=108$ by solving a five-dimensional collective Hamiltonian, the collective parameters of which are determined from triaxial relativistic mean field plus BCS calculation using the PC-PK1 force. After taking into account these beyond mean-field DCEs, the root-mean-square (rms) deviation with respect to nuclear masses is reduced significantly down to 1.14 MeV, which is smaller than those of other successful CEDFs: NL3* (2.96 MeV), DD-ME2 (2.39 MeV), $\mathrm{DD}\text{−}\mathrm{ME}\delta$ (2.29 MeV), and DD-PC1 (2.01 MeV). Moreover, the rms deviation for two-nucleon separation energies is reduced by $\sim 34\%$ in comparison with the cranking prescription.

We investigate unnatural-parity high-spin states in neutron-rich Cr and Fe isotopes using large-scale shell-model calculations. These shell-model calculations are carried out within the model space of $fp\text{-shell}+0g_{9/2}+1d_{5/2}$ orbits with the truncation allowing $1\hslash \omega$ excitation of a neutron. The effective Hamiltonian consists of GXPF1Br for $fp$-shell orbits and $V_{\mathrm{MU}}$ with a modification for the other parts. The present shell-model calculations can describe and predict the energy levels of both natural- and unnatural-parity states up to the high-spin states in Cr and Fe isotopes with $N\le 35$. The total energy surfaces present prolate deformations on the whole and indicate that the excitation of one neutron into the $0g_{9/2}$ orbit plays the role of enhancing prolate deformation. For positive (unnatural)-parity states in odd-mass Cr and Fe isotopes, their energy levels and prolate deformations indicate the decoupling limit of the particle-plus-rotor model. The sharp drop of the $9/2_1^{+}$ levels in going from $N=29$ to $N=35$ in odd-mass Cr, Fe, and Ni isotopes is explained by the Fermi surface approaching the $\nu 0g_{9/2}$ orbit.

Recent observation of the $6^{+}$ seniority isomers and measurements of the $B\left(E2\right)$ values in the ${}^{134\text{–}138}\mathrm{Sn}$ isotopes lying close to the neutron drip line have raised some questions about the validity of the currently used effective interactions in the neutron-rich region. Simpson et al. [Phys. Rev. Lett. 113, 132502 (2014)] had to modify the diagonal and nondiagonal $\nu f_{7/2}^2$ two-body matrix elements of the $Vlk$ interaction by $\sim 150$ keV in their shell model calculations in order to explain the data of ${}^{136}\mathrm{Sn}$. In contrast, we are able to explain the observed energy levels and the $B\left(E2\right)$ values after marginal reduction of the same set of matrix elements by $25$ keV in the RCDB (renormalized CD-Bonn) interaction. The observed mismatch in reproducing the data of ${}^{136}\mathrm{Sn}$ is due to the seniority mixing. Further, we do not find it necessary to consider the core excitations, and the RCDB interaction seems better suited to explain the data beyond $N=82$ magic number.