Assuming that the $f_2^{\prime }\left(1525\right), a_2\left(1320\right)$, and $K_2^{*}\left(1430\right)$ resonances are dynamically generated states from vector-meson–vector-meson interactions in the $s$-wave with spin $S=2$, we study the $\gamma p\to f_2^{\prime }\left(1525\right)p, \gamma p\to a_2^0\left(1320\right)p$, and $\gamma p\to K_2^{*}\left(1430\right)\mathrm{\Lambda }\left(\mathrm{\Sigma }\right)$ reactions. These reactions proceed in the following way: the incoming photon first mutates into a ${\rho }^0, \omega$, or $\varphi$ meson via vector-meson dominance, which then interacts with the ${\rho }^0, \omega$, or $K^{*}$ emitted by the incoming proton to form the tensor mesons $f_2^{\prime }\left(1525\right), a_2\left(1320\right)$, and $K_2^{*}\left(1430\right)$. The picture is simple and has no free parameters, as all the parameters of the mechanism have been fixed in previous studies. We predict the differential and total cross sections of these reactions. The results can be tested in future experiments and therefore offer new clues about the nature of these tensor states.

Excited states in the neutron-deficient nuclides ${}_{74}{}^{162}\mathrm{W}_{88}$ and ${}_{74}{}^{164}\mathrm{W}_{90}$ were investigated by using the $\gamma$-ray spectrometer Jurogam. A change in structure is apparent from the first rotational alignments in ${}^{162}\mathrm{W}$ and ${}^{164}\mathrm{W}$, whose rotationally aligned bands are interpreted as $\nu {\left(h_{9/2}\right)}^2$ and $\nu {\left(i_{13/2}\right)}^2$ configurations, respectively. The level schemes have been extended using recoil (-decay) correlations with the observation of excited collective structures. Configuration assignments have been made on the basis of comparisons of the deduced aligned angular momentum, as a function of rotational frequency, with the predictions of the cranked shell model.

The neutron-deficient nucleus ${}^{107}\mathrm{Sn}$ has been studied by using the one-neutron knockout reaction. By measuring the decay $\gamma$ rays and momentum distributions of reaction residues, the spins of the ground, $5/2^{+}$, and first-excited, $7/2^{+}$, states of ${}^{107}\mathrm{Sn}$ have been assigned by comparisons to eikonal-model reaction calculations. Limits on the inclusive and exclusive cross sections have been measured and transitions due to neutron removals from below the $N=50$ closed shell have been observed. New excited states up to $5.5$ MeV in ${}^{107}\mathrm{Sn}$ have been identified.

The PHENIX experiment at the Relativistic Heavy Ion Collider has measured $\varphi$ meson production and its nuclear modification in asymmetric $\mathrm{Cu}+\mathrm{Au}$ heavy-ion collisions at $\sqrt{s_{\mathit{NN}}}=200$ GeV at both forward Cu-going direction $\left(1.2<y<2.2\right)$ and backward Au-going direction $\left(-2.2<y<-1.2\right)$ rapidities. The measurements are performed via the dimuon decay channel and reported as a function of the number of participating nucleons, rapidity, and transverse momentum. In the most central events, 0%–20% centrality, the $\varphi$ meson yield integrated over $1<p_T<5$ GeV/$c$ prefers a smaller value, which means a larger nuclear modification, in the Cu-going direction compared to the Au-going direction. Additionally, the nuclear-modification factor in $\mathrm{Cu}+\mathrm{Au}$ collisions averaged over all centrality is measured to be similar to the previous PHENIX result in $d+\mathrm{Au}$ collisions for these rapidities.

Ultracold neutrons (UCNs) were produced in superfluid helium using the PF1B cold-neutron beam facility at the Institut Laue-Langevin. A 4-liter beryllium-coated converter volume with a mechanical valve and windowless stainless-steel extraction system were used to accumulate and guide UCNs to a detector at room temperature. At a converter temperature of 1.08 K the total storage time constant in the vessel was $(20.3\pm 1.2)\mathrm{s}$ and the number of UCNs counted after accumulated was $91700\pm 300$. From this, we derive a volumetric UCN production rate of $(6.9\pm 1.7){\mathrm{cm}}^{-3}{\mathrm{s}}^{-1}$, which includes a correction for losses in the converter during UCN extraction caused by the short storage time, but not accounting for UCN transport and detection efficiencies. The up-scattering rate of UCNs caused by excitations in the superfluid was studied by scanning the temperature between $1.2$ K and $2.4\mathrm{K}$. Using the temperature-dependent UCN production rate calculated from inelastic neutron scattering data, the only UCN up-scattering process found to occur was from two-phonon scattering. Our analysis for $T<1.95\mathrm{K}$ rules out the contributions from roton-phonon scattering to $<29\%$ (95% C.I.) and from one-phonon absorption to $<47\%$ (95% C.I.) of their predicted levels.

We propose an importance-truncation scheme for the large-scale nuclear shell model that extends its range of applicability to larger valence spaces and midshell nuclei. It is based on a perturbative measure for the importance of individual basis states that acts as an additional truncation for the many-body model space in which the eigenvalue problem of the Hamiltonian is solved numerically. Through a posteriori extrapolations of all observables to vanishing importance threshold, the full shell-model results can be recovered. In addition to simple threshold extrapolations, we explore extrapolations based on the energy variance. We apply the importance-truncated shell model for the study of ${}^{56}\mathrm{Ni}$ in the $pf$ valence space and of ${}^{60}\mathrm{Zn}$ and ${}^{64}\mathrm{Ge}$ in the $pf{g}_{9/2}$ space. We demonstrate the efficiency and accuracy of the approach, which pave the way for future applications of valence-space interactions derived in ab initio approaches in larger valence spaces.

Background: The advent of new dedicated experimental programs on hyperon physics is rapidly boosting the field, and the possibility of synthesizing multiple strange hypernuclei requires the addition of the strangeness degree of freedom to the models dedicated to nuclear structure and nuclear matter studies at low energy.

Purpose: We want to settle the influence of strangeness on the nuclear liquid-gas phase transition. Because of the large uncertainties concerning the hyperon sector, we do not aim at a quantitative estimation of the phase diagram but rather at a qualitative description of the phenomenology, as model independent as possible.

Method: We analyze the phase diagram of low-density matter composed of neutrons, protons, and $\mathrm{\Lambda }$ hyperons using a relativistic mean field (RMF) model. We largely explore the parameter space to pin down generic features of the phase transition, and compare the results to ab initio quantum Monte Carlo calculations.

Results: We show that the liquid-gas phase transition is only slightly quenched by the addition of hyperons. Strangeness is seen to be an order parameter of the phase transition, meaning that dilute strange matter is expected to be unstable with respect to the formation of hyperclusters.

Conclusions: More quantitative results within the RMF model need improved functionals at low density, possibly fitted to ab initio calculations of nuclear and $\mathrm{\Lambda }$ matter.

Background: At above-barrier energies, complete fusion cross sections in collisions of light weakly bound nuclei with heavy target nuclei are suppressed when compared to well-bound nuclei. Breakup of the projectilelike nucleus was proposed to be the cause. In addition to direct breakup, breakup following transfer was shown to be substantial.

Purpose: We investigate breakup in reactions with ${}^7\mathrm{Li}$, triggered by sub-barrier proton pickup to unbound states in ${}^8\mathrm{Be}$, which subsequently separate into two $\alpha$ particles.

Method: Measurements of sub-barrier disintegration of ${}^7\mathrm{Li}$ on a ${}^{58}\mathrm{Ni}$ target were made using the Heavy Ion Accelerator Facility at the Australian National University. Combining the experimental results with classical simulations of post-breakup acceleration, we study the sensitivity of $\alpha -\alpha$ energy and angle correlations to the proximity of disintegration to the target (proton donor) nucleus.

Results: The simulations indicate that disintegration as the colliding nuclei approach each other leads to large angular separations ${\theta }_{12}$ of the $\alpha$ fragments. The detectors allow for a maximum opening angle of ${\theta }_{12}={132}^{\circ }$, such that the present experiment is largely insensitive to breakup occurring when the collision partners approach each other. The data are consistent with disintegration of (a) the $0^{+}{}^8\mathrm{Be}$ ground state far from the targetlike nucleus, and (b) the $2^{+}{}^8\mathrm{Be}$ resonance near the targetlike nucleus when the ${}^8\mathrm{Be}$ is receding from the targetlike nucleus.

Conclusions: The present results shed light on the near-target component of transfer-induced breakup reactions. The distribution of events with respect to the opening angle of the $\alpha$ particles, and the orientation of their relative velocity with respect to the velocity of their center of mass, gives insights into their proximity to the target at the moment of breakup. Further measurements with larger angular coverage and more complete simulations are required to fully understand the influence of breakup on fusion.

A coordinate-dependent effective mass for the proton is considered to calculate half-lives of spontaneous one-proton emission from exotic nuclei. This dynamical change to treat proton-nucleus interaction using this type of effective mass was recently employed successfully for description of proton-nucleus quantum scattering, by Jaghoub et al. [Phys. Rev. C 84, 034618 (2011)] and Zureikat and Jaghoub [Nucl. Phys. A 916, 183 (2013)]. The introduced coordinate dependency of the effective mass incorporates nonlocality features of the proton-nucleus interaction for the scattering problem. In the present work the treatment is extended to the proton emission of neutron deficient nuclei. The WKB barrier penetrability factor is determined for proton decay and the half-life is calculated. It is also shown that the tunneling approach is still applicable when a coordinate-dependent effective mass is considered. The real part of the Becchetti and Greenlees [Phys. Rev. 182, 1190 (1969)] nuclear shell model parametrization is taken to generate the barrier tunneled by the proton. This procedure leads practically to only one free parameter in the effective mass for the entire calculation of the half-lives of the whole set of existing almost spherical proton emitters. In the universe of 32 proton emitters studied we have obtained an excellent agreement for 25 of them, while for the remaining seven emitters it was necessary to add an additional fine tuning, realized by a small change in the nuclear radius parameter definition.

Measurements of midrapidity charged-particle multiplicity distributions, $d{N}_{\mathrm{ch}}/d\eta$, and midrapidity transverse-energy distributions, $d{E}_T/d\eta$, are presented for a variety of collision systems and energies. Included are distributions for $\mathrm{Au}+\mathrm{Au}$ collisions at $\sqrt{s_{{}_{NN}}}=200$, 130, 62.4, 39, 27, 19.6, 14.5, and 7.7 GeV, $\mathrm{Cu}+\mathrm{Cu}$ collisions at $\sqrt{s_{{}_{NN}}}=200$ and 62.4 GeV, $\mathrm{Cu}+\mathrm{Au}$ collisions at $\sqrt{s_{{}_{NN}}}=200$ GeV, $\mathrm{U}+\mathrm{U}$ collisions at $\sqrt{s_{{}_{NN}}}=193$ GeV, $d+\mathrm{Au}$ collisions at $\sqrt{s_{{}_{NN}}}=200$ GeV, ${}^3\mathrm{He}+\mathrm{Au}$ collisions at $\sqrt{s_{{}_{NN}}}=200$ GeV, and $p+p$ collisions at $\sqrt{s_{{}_{NN}}}=200$ GeV. Centrality-dependent distributions at midrapidity are presented in terms of the number of nucleon participants, $N_{\mathrm{part}}$, and the number of constituent quark participants, $N_{\mathrm{qp}}$. For all $A+A$ collisions down to $\sqrt{s_{{}_{NN}}}=7.7$ GeV, it is observed that the midrapidity data are better described by scaling with $N_{\mathrm{qp}}$ than scaling with $N_{\mathrm{part}}$. Also presented are estimates of the Bjorken energy density, ${\varepsilon }_{\mathrm{BJ}}$, and the ratio of $d{E}_T/d\eta$ to $d{N}_{\mathrm{ch}}/d\eta$, the latter of which is seen to be constant as a function of centrality for all systems.

A further development of the evolutionary picture of $A+A$ collisions, which we call the integrated hydrokinetic model (iHKM), is proposed. The model comprises a generator of the initial state GLISSANDO, prethermal dynamics of $A+A$ collisions leading to thermalization, subsequent relativistic viscous hydrodynamic expansion of quark-gluon and hadron medium (vHLLE), its particlization, and finally the hadronic cascade ultrarelativistic QMD. We calculate midrapidity charged-particle multiplicities, pion, kaon, and antiproton spectra, charged-particle elliptic flows, and pion interferometry radii for Pb + Pb collisions at the energies available at the CERN Large Hadron Collider, $\sqrt{s}=2.76$ TeV, at different centralities. We find that the best description of the experimental data is reached when the initial states are attributed to the very small initial time 0.1 fm/$c$, the prethermal stage (thermalization process) lasts at least until 1 fm/$c$, and the shear viscosity at the hydrodynamic stage of the matter evolution has its minimal value, $\eta /s=\frac{1}{4\pi }$. At the same time it is observed that the various momentum anisotropies of the initial states, different initial and relaxation times, as well as even a treatment of the prethermal stage within just viscous or ideal hydrodynamic approach, lead sometimes to worse but nevertheless similar results $\mathit{if}$ the normalization of maximal initial energy density in most central events is adjusted to reproduce the final hadron multiplicity in each scenario. This can explain a good enough data description in numerous variants of hybrid models without a prethermal stage when the initial energy densities are defined up to a common factor.

We calculate the genuine long-range multiparticle rapidity correlation functions, $C_n(y_1,\cdots ,y_n)$ for $n=2,3,4,5,6$, originating from fluctuations of the fireball longitudinal shape. In these correlation functions any contribution from the short-range two-particle correlations, and in general up to particle $(n-1)$ in $C_n$, is suppressed. The information about the fluctuating fireball shape in rapidity is encoded in the cumulants of coefficients of the orthogonal polynomial expansion of particle distributions in rapidity.

The pentaquark component $\mathit{uuds}\overline{s}$ is included in the proton wave functions to study $\varphi$ meson production proton-antiproton annihilation reactions. With all possible configurations of the $\mathit{uuds}$ subsystem proposed for describing the strangeness spin and magnetic moment of the proton, we estimate the branching ratios of the annihilation reactions at rest $p\overline{p}\to \varphi X$ ($X={\pi }^0,\eta ,{\rho }^0,\omega$) from atomic $p\overline{p} S$- and $P$-wave states by using effective quark line diagrams incorporating the ${}^3{P}_0$ model. The best agreement of theoretical prediction with the experimental data is found when the pentaquark configuration of the proton wave function takes the flavor-spin symmetry ${\left[4\right]}_{\mathrm{FS}}{\left[22\right]}_F{\left[22\right]}_S$.

Chiral effective field theory (EFT) enables a systematic description of low-energy hadronic interactions with controlled theoretical uncertainties. For strongly interacting systems, quantum Monte Carlo (QMC) methods provide some of the most accurate solutions, but they require as input local potentials. We have recently constructed local chiral nucleon-nucleon (NN) interactions up to next-to-next-to-leading order (${\mathrm{N}}^2\mathrm{LO}$). Chiral EFT naturally predicts consistent many-body forces. In this paper, we consider the leading chiral three-nucleon (3N) interactions in local form. These are included in auxiliary field diffusion Monte Carlo (AFDMC) simulations. We present results for the equation of state of neutron matter and for the energies and radii of neutron drops. In particular, we study the regulator dependence at the Hartree-Fock level and in AFDMC and find that present local regulators lead to less repulsion from 3N forces compared to the usual nonlocal regulators.

Neutron capture cross sections have been calculated in nuclei near the $N=82$ neutron shell-closure. These nuclei are of astrophysical interest, participating in the $s$-process and the $p$-process. A semimicroscopic optical model has been used with the potential being obtained through folding the target density with the DDM3Y nucleon-nucleon interaction. Theoretical density values have been calculated using the relativistic mean-field approach. The calculated cross sections, as a function of neutron energy, agree reasonably well with experimental measurements. Maxwellian-averaged cross sections, important for astrophysical processes, have been calculated.

Background: In our earlier study of the ${}^{12}\mathrm{C}+{}^{93}\mathrm{Nb}\to {}^{105}\mathrm{Ag}^{*}$ reaction at three near- and below-barrier energies ($E_{\mathrm{c}.\mathrm{m}.}=41.097$, 47.828, and 54.205 MeV), using the dynamical cluster-decay model (DCM) with various nuclear interaction potentials (the Blocki et al. pocket formula and others derived from the Skyrme energy density formalism) for compact, coplanar $\left({\mathrm{\Phi }}_c=0^0\right)$ nuclei, we found a large non-compound-nucleus (nCN) contribution in the measured fusion cross section of this reaction.

Purpose: In the present work, we look for the effect of using non-coplanar, compact configurations $\left({\mathrm{\Phi }}_c\ne 0^0\right)$, in the Blocki et al. pocket formula of the nuclear proximity potential, on the non-compound-nucleus (nCN) contribution, using the DCM.

Methods: Allowing the $\mathrm{\Phi }$ degree of freedom in the DCM formalism, we calculate the compound-nucleus (CN) and nCN cross sections. The only parameter of the DCM is the neck-length parameter $\mathrm{\Delta }R$, which also fits the empirically determined nCN cross section nearly exactly, under the assumption of considering it like a quasifission process where the fragment preformation factor $P_0=1$.

Results: With the $\mathrm{\Phi }$ degree of freedom included, at the higher two energies the nCN cross section gets enhanced, and hence the pure CN cross section is decreased, since the calculated (total) fusion cross section is fitted to experimental data. The parameter $\mathrm{\Delta }R$ for the nCN contribution is smaller, and hence the reaction time larger, than for the CN decay process. Also, the contributing angular momentum ${\ell }_{\max }$ value increases in going from ${\mathrm{\Phi }}_c=0^0$ to ${\mathrm{\Phi }}_c\ne 0^0$ for both the CN and nCN processes. The intermediate mass fragments (IMFs), measured up to mass 13 in this reaction, are shown extended up to mass 16, and the fusion-fission $\left(ff\right)$ region is identified as $A/2\pm 16$, the same as for the ${\mathrm{\Phi }}_c=0^0$ case.

Conclusions: As a result of enhanced nCN cross section due to ${\mathrm{\Phi }}_c\ne 0^0$, the CN fusion probability $P_{\mathrm{CN}}$ for ${}^{105}\mathrm{Ag}^{*}$ changes its behavior from an increasing to a decreasing function of center-of-mass energy $E_{\mathrm{c}.\mathrm{m}.}$, and hence belongs to the group of weakly fissioning nuclei, instead of the strongly fissioning superheavy nuclei for ${\mathrm{\Phi }}_c=0^0$. On the other hand, with measured IMFs taken to represent the $ff$ component, non-coplanarity simply increases the magnitude of CN survival probability $P_{\mathrm{surv}}$, although its functional dependence on $E_{\mathrm{c}.\mathrm{m}.}$ remains the same as for weakly fissioning nuclei. In other words, on adding the $\mathrm{\Phi }$ degree of freedom, the inconsistent result of $P_{\mathrm{CN}}$ behaving like strongly fissioning superheavy nuclei and $P_{\mathrm{surv}}$ like the weakly fissioning nuclei for ${\mathrm{\Phi }}_c=0^0$ changes to both $P_{\mathrm{CN}}$ and $P_{\mathrm{surv}}$ behaving consistently like those of weakly fissioning nuclei. Thus, our calculations advocate for ${\mathrm{\Phi }}_c$ as an important degree of freedom, like deformations of nuclei themselves.

Converged continuum discretized coupled-channel calculations of elastic-scattering differential cross sections for reactions induced by the ${}^6\mathrm{Li}$ projectile on the ${}^{144}\mathrm{Sm}$ target, at energies around the Coulomb barrier, are presented. The impact of the low-lying $\alpha$-deuteron resonant states in ${}^6\mathrm{Li}$ $\left(l=2,J^{\pi }=3^{+},2^{+},1^{+}\right)$ on those elastic angular distributions is quantified. This is done by two types of calculations, namely, (a) by omitting from the continuum energy spectrum all states where the resonances are constructed in the discretization process, and (b) by considering only the resonance discretized space. Dynamical polarization potentials are used for interpreting the effect of continuum couplings. Resonant couplings play a more significant role than nonresonance ones at back-scattering angles and at incident energies below the Coulomb barrier. However, their effect becomes weaker as the incident energy increases above the barrier energy.

Background: The $p$ nuclei, which are not produced by neutron capture processes, are present with a typical isotopic abundance of 0.01%–0.3%. Abundance decreases with an increase in atomic number. However, the neutron-magic isotopes of ${}^{92}\text{Mo}$ and ${}^{144}\text{Sm}$ exhibit unusually large abundances in comparison. A combination of proton and $\alpha$-particle capture reactions and neutron emission reactions are key to understanding this issue. Currently, complex network calculations do not have access to much experimental data, and hence require theoretically predicted reaction rates in order to estimate final abundances produced in nucleosynthesis.

Purpose: Few experimental cross sections of $(p$,γ) reactions on heavy nuclides with mass numbers of 130–150 have been reported. The ${}^{144}\text{Sm}(p,\gamma ){}^{145}\text{Eu}$ reaction is the main destruction pathway for the nucleosynthesis of the ${}^{144}\text{Sm}$ nuclide. In the present paper, experimental cross sections of the ${}^{144}\text{Sm}(p,\gamma ){}^{145}\text{Eu}$ reaction at a range including astrophysically relevant energies for the $p$ process were determined to compare with theoretical predictions using the Hauser-Feshback statistical model.

Methods: The ${}^{144}\text{Sm}$ was deposited on a high-purity Al foil with the molecular plating method. Stacks consisting of Ta degrader foils, ${}^{144}\text{Sm}$ targets, and Cu foils used as flux monitors were irradiated with 14.0-MeV proton beams. The ${}^{144}\text{Sm}(p,\gamma ){}^{145}\text{Eu}$ cross sections were determined from the ${}^{145}\text{Eu}$ activities and the proton fluence estimated from the ${}^{65}\text{Zn}$ activity in the Cu monitor foil. The proton energies bombarded on each ${}^{144}\text{Sm}$ target were estimated using srim2013.

Results: We determined the ${}^{144}\text{Sm}(p,\gamma ){}^{145}\text{Eu}$ cross sections at proton energies between 2.8 and 7.6 MeV. These energies encompass nucleosynthesis temperatures between 3 and 5 GK. The cross sections at energies higher than 3.8 MeV agreed well with theoretically predicted cross sections using talys using the generalized superfluid (GS) model for level densities. However, calculations using non-smoker overestimated the cross section. When the components of the energy uncertainties in the experimental cross sections were corrected, the cross sections at energies lower than 3.8 MeV showed comparable values with talys but higher than those predicted by both non-smoker and talys.

Conclusions: talys using the GS model reproduced well the experimental cross sections without correction of the proton widths at energies between 2.8 and 7.6 MeV. Thus, the reaction rates of ${}^{144}\text{Sm}(p,\gamma ){}^{145}\text{Eu}$ in the stellar environment at 2.5–5 GK estimated with talys corresponded with those by the experimental cross section within 10%. However, the reaction rates depended on the extrapolation of the cross section at energies of 0–2.8 MeV at temperatures of 0.5–2.5 GK. The reaction rate estimated by talys employing the GS model showed an uncertainty within a factor of 2 at 1.5–3.5 GK for nucleosynthesis temperatures of the $p$ nuclei.

Several lifetimes in ${}^{23}\text{Mg}$ have been determined for the first time using the Doppler-shift attenuation method. A Monte Carlo simulation code has been written to model the $\gamma$-ray line shape. An upper limit of $\tau <12$ fs at the 95% C.L. has been obtained for the astrophysically important 7787 keV state.