Using a fully quantum mechanical post-form finite-range distorted-wave Born approximation theory of Coulomb breakup, I study the parallel momentum distribution of the core in the Coulomb breakup of suggested excited-state one-neutron halo nuclei considered in their different bound excited states. Narrow momentum distributions obtained in the present calculations for some cases indicate the possibilities of the excited-state halo structure in the nuclei under consideration and therefore favor the previous predictions.

Chiral symmetry is always broken in cold, dense matter, by chiral condensation at low densities and by diquark condensation at high density. We construct here, within a schematic Nambu–Jona-Lasinio model, the corresponding generalized Nambu-Goldstone pion, ${\pi }_G$. As we show, the ${\pi }_G$ mode naturally emerges as a linear combination of the $\langle \overline{q}q\rangle$ vacuum pion $\pi$ and the $\langle qq\rangle$ diquark-condensate pion $\tilde{\pi }$, with $q$ the quark field, and continuously evolves with increasing density from being $\pi$-like in the vacuum to $\tilde{\pi }$-like in the high density diquark pairing phase. We calculate the density-dependent mass, decay constant, and coupling to quarks of the ${\pi }_G$, and derive a generalized Gell-Mann–Oakes–Renner relation in the presence of a finite bare quark mass $m_q$. We briefly discuss the implications of the results to possible Bose condensation of ${\pi }_G$ in more realistic models.

We investigated effects of pairing correlations on the neutron skin thickness and the symmetry energy of finite nuclei. In this calculation we used Hartree-Fock-Bogoliubov method with Skyrme forces and effective pairing interactions. The results have been compared with available experimental data, Hartree-Fock results as well as the predictions by droplet model. Finally, our discussion was extended to study of the pairing interaction in nuclear matter. Roles of isospin $T=0$ pairing in the nuclear matter were also discussed.

We present a new scheme to select the most relevant phonons in the phonon-coupling model, named here the time-blocking approximation (TBA). The new criterion, based on the phonon-nucleon coupling strengths rather than on $B\left(EL\right)$ values, is more selective and thus produces much smaller phonon spaces in the TBA. This is beneficial in two respects: first, it curbs the computational cost, and second, it reduces the danger of double counting in the expansion basis of the TBA. We use here the TBA in a form where the coupling strength is regularized to keep the given Hartree-Fock ground state stable. The scheme is implemented in a random-phase approximation and TBA code based on the Skyrme energy functional. We first explore carefully the cutoff dependence with the new criterion and can work out a natural (optimal) cutoff parameter. Then we use the freshly developed and tested scheme for a survey of giant resonances and low-lying collective states in six doubly magic nuclei looking also at the dependence of the results when varying the Skyrme parametrization.

The $(d,n)$ reaction has been studied with targets of ${}^9\mathrm{Be}, {}^{11}\mathrm{B}, {}^{13}\mathrm{C}, {}^{14,15}\mathrm{N}$, and ${}^{19}\mathrm{F}$ at $E_d=16\mathrm{MeV}$ using a deuterated liquid-scintillator array. Advanced spectral unfolding techniques with accurately measured scintillator response functions were employed to extract neutron energy spectra without the need for long-path neutron time-of-flight. An analysis of the proton-transfer data at forward angles to the ground states of the final nuclei, using finite-range distorted-wave Born approximation analysis with common bound-state, global, and local optical-model parameter sets, yields a set of self-consistent spectroscopic factors. These are compared with the results of several previous time-of-flight measurements, most done many years ago for individual nuclei at lower energy and often analyzed using zero-range transfer codes. In contrast to some of the earlier published data, our data generally compare well with simple shell-model predictions, with little evidence for uniform quenching (reduction from shell-model values) that has previously been reported from analysis of nucleon knock-out reactions. Data for low-lying excited states in ${}^{14}\mathrm{N}$ from ${}^{13}\mathrm{C}(d,n)$ also is analyzed and spectroscopic information relevant to nuclear astrophysics obtained. A preliminary study of the radioactive ion beam induced reaction ${}^7\mathrm{Be}(d,n), E\left({}^7\mathrm{Be}\right)=30\mathrm{MeV}$ was carried out and indicates further improvements are needed for such measurements, which require detection of neutrons with $E_n<2\mathrm{MeV}$.

Using a chiral kinetic approach based on initial conditions from a multiphase transport model, we study the spin polarizations of quarks and antiquarks in noncentral heavy ion collisions at the BNL Relativistic Heavy Ion Collider. Because of the nonvanishing vorticity field in these collisions, quarks and antiquarks are found to acquire appreciable spin polarizations in the direction perpendicular to the reaction plane. Converting quarks and antiquarks to hadrons via the coalescence model, we further calculate the spin polarizations of $\mathrm{\Lambda }$ and anti-$\mathrm{\Lambda }$ hyperons and find their values comparable to those measured in experiments by the STAR Collaboration.

We report a measurement of $e^{+}{e}^{-}$ pairs from semileptonic heavy-flavor decays in $p+p$ collisions at $\sqrt{s_{{}_{\mathit{\text{NN}}}}}=200$ GeV. The $e^{+}{e}^{-}$ pair yield from $b\overline{b}$ and $c\overline{c}$ is separated by exploiting a double differential fit done simultaneously in dielectron invariant mass and $p_T$. We used three different event generators, pythia, mc@nlo, and powheg, to simulate the $e^{+}{e}^{-}$ spectra from $c\overline{c}$ and $b\overline{b}$ production. The data can be well described by all three generators within the detector acceptance. However, when using the generators to extrapolate to $4\pi$, significant differences are observed for the total cross section. These difference are less pronounced for $b\overline{b}$ than for $c\overline{c}$. The same model dependence was observed in already published $d+A$ data. The $p+p$ data are also directly compared with $d+A$ data in mass and $p_T$, and within the statistical accuracy no nuclear modification is seen.

We use an improved version of the SU(3) flavor parity-doublet quark-hadron model to investigate the higher-order baryon number susceptibilities near the chiral and the nuclear liquid-gas transitions. The parity-doublet model has been improved by adding higher-order interaction terms of the scalar fields in the effective mean field Lagrangian, resulting in a much-improved description of nuclear ground-state properties, in particular the nuclear compressibility. The resulting phase diagram of the model agrees qualitatively with expectations from lattice QCD, i.e., it shows a crossover at zero net baryochemical potential and a critical point at finite density. Using this model, we investigate the dependence of the higher-order baryon number susceptibilities as a function of temperature and chemical potential. We observe a strong interplay between the chiral and liquid-gas transition at intermediate baryochemical potentials. Due to this interplay between the chiral and the nuclear liquid-gas transitions, the experimentally measured cumulants of the net baryon number may show very different beam energy dependence, subject to the actual freeze-out temperature.

The $\nu 0h_{9/2}$ and $\nu 0i_{13/2}$ strength at ${}^{137}\mathrm{Xe}$, a single neutron outside the $N=82$ shell closure, has been determined using the ${}^{136}\mathrm{Xe}(\alpha ,{}^3\mathrm{He}){}^{137}\mathrm{Xe}$ reaction carried out at 100 MeV. We confirm the recent observation of the second $13/2^{+}$ state and reassess previous data on the $9/2^{-}$ states, obtaining spectroscopic factors. These new data provide additional constraints on predictions of the same single-neutron excitations at ${}^{133}\mathrm{Sn}$.

Radiative neutron capture is an important nuclear reaction whose accurate description is needed for many applications ranging from nuclear technology to nuclear astrophysics. The description of such a process relies on the Hauser-Feshbach theory which requires the nuclear optical potential, level density, and $\gamma$-strength function as model inputs. It has recently been suggested that the $M1$ scissors mode may explain discrepancies between theoretical calculations and evaluated data. We explore statistical model calculations with the strength of the $M1$ scissors mode estimated to be dependent on the nuclear deformation of the compound system. We show that the form of the $M1$ scissors mode improves the theoretical description of evaluated data and the match to experiment in both the fission product and actinide regions. Since the scissors mode occurs in the range of a few keV to a few MeV, it may also impact the neutron capture cross sections of neutron-rich nuclei that participate in the rapid neutron capture process of nucleosynthesis. We comment on the possible impact to nucleosynthesis by evaluating neutron capture rates for neutron-rich nuclei with the $M1$ scissors mode active.

The concept of cluster radioactivity has been extended to allow emitted particles with $Z_C>28$ for superheavy nuclei by nuclear theory [Poenaru et al., Phys. Rev. Lett. 107, 062503 (2011)]. The preformation and emission mechanics of heavy-ion particles must be examined again before the fascinating radioactivity is observed for superheavy nuclei in laboratory. We extract the cluster preformation factor for heavy and superheavy nuclei within a preformed cluster model, in which the decay constant is the product of the preformation factor, assault frequency, and penetration probability. The calculated results show that the cluster penetration probability for superheavy nuclei is larger than that for actinide elements. The preformation factor depends on the nuclear structures of the emitted cluster and mother nucleus, and the well-known cluster preformation law $S\left(A_C\right)=S{\left(\alpha \right)}^{\left(A_C-1\right)/3}$ [Blendowske and Walliser, Phys. Rev. Lett. 61, 1930 (1988)] will break down when the mass number of the emitted cluster $A_c>28$, and new preformation formulas are proposed to estimate the preformation factor for heavy and superheavy nuclei.

The binding-energy pattern along the neutron-rich oxygen chain, governed by an interplay between shell effects and many-body correlations impacted by strong couplings to one- and two-neutron continua, make these isotopes a unique testing ground for nuclear models. In this work, we investigate ground states and low-lying excited states of ${}^{23-28}\mathrm{O}$ using the complex-energy Gamow shell model and density matrix renormalization group method with a finite-range two-body interaction optimized to the bound states and resonances of ${}^{23-26}\mathrm{O}$, assuming a core of ${}^{22}\mathrm{O}$. Our results suggest that the ground state of ${}^{28}\mathrm{O}$ has a threshold character, i.e., is very weakly bound or slightly unbound. We also predict narrow excited resonances in ${}^{25}\mathrm{O}$ and ${}^{27}\mathrm{O}$. The inclusion of the large continuum space significantly impacts predicted binding energies of ${}^{26-28}\mathrm{O}$. This implies that the careful treatment of a neutron continuum is necessary prior to assessing the spectroscopic quality of effective interactions in this region.

The $\left(\nu \frac{5}{2}\left[532\right]\otimes \frac{3}{2}\left[411\right]\right)$ $4^{-}$ state in ${}^{102}\mathrm{Zr}$, populated in the $\beta$ decay of ${}^{102}\mathrm{Y}$, has been measured to be isomeric with a mean lifetime of 9.5(7) ns. It decays via four transitions, two of which are $\mathrm{\Delta }K=2$ (to the $3^{+}$ and $4^{+}$ members of the $2_{\gamma }^{+}$ band) and one is $\mathrm{\Delta }K=4$ (to the $4^{+}$ member of the ground state $0^{+}$ band). The fourth (low-energy) transition is inferred to decay to an as-yet unassigned state. Hindrances of ${10}^6$ were derived for the $\mathrm{\Delta }K=2$ transitions compared to Weisskopf estimates and the $\mathrm{\Delta }K=4$ transition hindered by a factor of ${10}^9$. These values are consistent with the decay pattern of the analogous isomeric state in the neighboring $N=62$ nucleus ${}^{100}\mathrm{Sr}$ and with the broader systematics of such transitions. A comparison of the hindrances for the $\mathrm{\Delta }K=4$ transitions suggests that ${}^{102}\mathrm{Zr}$ is hardened against the $\gamma$ degree of freedom compared to ${}^{100}\mathrm{Sr}$.

Local correlations of $2_1{}^{+}$ excitation energies and $B(E2,2_1{}^{+}\to \text{g.s.})$ values require linear $N_p{N}_n$ systematics in a logarithmic scale, as confirmed by an experiment survey. Based on local correlations of $\alpha$-decay energies, neutron separation energies, and proton separation energies, one can decouple them into their proton and neutron contributions separately. These contributions exhibit smooth regional systematics beyond the $N_p{N}_n$ scheme.

Quantal diffusion mechanism of nucleon exchange is studied in the central collisions of ${}^{238}\mathrm{U}+{}^{238}\mathrm{U}$ in the framework of the stochastic mean-field (SMF) approach. For bombarding energies considered in this work, the dinuclear structure is maintained during the collision. Hence, it is possible to describe nucleon exchange as a diffusion process for mass and charge asymmetry. Quantal neutron and proton diffusion coefficients, including memory effects, are extracted from the SMF approach and the primary fragment distributions are calculated.

The STAR Collaboration reports the measurement of semi-inclusive distributions of charged-particle jets recoiling from a high transverse momentum hadron trigger, in central and peripheral $\mathrm{Au}+\mathrm{Au}$ collisions at $\sqrt{s_{\mathrm{NN}}}=200$ GeV. Charged jets are reconstructed with the anti-$k_{\mathrm{T}}$ algorithm for jet radii $R$ between 0.2 and 0.5 and with low infrared cutoff of track constituents ($p_{\mathrm{T}}>0.2 \mathrm{GeV}/\mathrm{c}$). A novel mixed-event technique is used to correct the large uncorrelated background present in heavy ion collisions. Corrected recoil jet distributions are reported at midrapidity, for charged-jet transverse momentum $p_{\mathrm{T},\mathrm{jet}}^{\mathrm{ch}}<30 \mathrm{GeV}/\mathrm{c}$. Comparison is made to similar measurements for $\mathrm{Pb}+\mathrm{Pb}$ collisions at $\sqrt{s}=2.76$ TeV, to calculations for $p+p$ collisions at $\sqrt{s}=200$ GeV based on the pythia Monte Carlo generator and on a next-to-leading order perturbative QCD approach, and to theoretical calculations incorporating jet quenching. The recoil jet yield is suppressed in central relative to peripheral collisions, with the magnitude of the suppression corresponding to medium-induced charged energy transport out of the jet cone of $2.8\pm 0.2\left(\mathrm{stat}\right)\pm 1.5\left(\mathrm{sys}\right)$ $\mathrm{GeV}/c$, for $10<p_{\mathrm{T},\mathrm{jet}}^{\mathrm{ch}}<20$ $\mathrm{GeV}/c$ and $R=0.5$. No medium-induced change in jet shape is observed for $R<0.5$. The azimuthal distribution of low-$p_{\mathrm{T},\mathrm{jet}}^{\mathrm{ch}}$ recoil jets may be enhanced at large azimuthal angles to the trigger axis, due to scattering off quasiparticles in the hot QCD medium. Measurement of this distribution gives a 90% statistical confidence upper limit to the yield enhancement at large deflection angles in central $\mathrm{Au}+\mathrm{Au}$ collisions of $50\pm 30\left(\mathrm{sys}\right)\%$ of the large-angle yield in $p+p$ collisions predicted by pythia.

Antiproton-proton annihilation into light neutral mesons in the few GeV energy domain is investigated in view of a global description of the existing data and predictions for future work at the Antiproton Annihilation at Darmstadt (PANDA) experiment at the Facility for Antiproton and Ion Research (FAIR). An effective meson model earlier developed, with mesonic and baryonic degrees of freedom in $s, t$, and $u$ channels, is applied here to ${\pi }^0{\pi }^0$ production. Form factors with logarithmic $s$ and $t\left(u\right)$ dependencies are applied. A fair agreement with the existing angular distributions is obtained. Applying SU(3) symmetry, it is straightforward to recover the angular distributions for ${\pi }^0\eta$ and $\eta \eta$ production in the same energy range. A good agreement is generally obtained with all existing data.

We study the finite-size effects, like the surface and Coulomb energies, on the hadron-quark mixed phase in neutron stars. The equilibrium conditions for coexisting hadronic and quark phases are derived by minimizing the total energy including the surface and Coulomb contributions, which are different from the Gibbs conditions without finite-size effects. We employ the relativistic mean-field model to describe the hadronic phase, while the Nambu-Jona-Lasinio model with vector interactions is used for the quark phase. It is found that finite-size effects can significantly reduce the region of the mixed phase, and the results lie between those of the Gibbs and Maxwell constructions. We show that a massive star may contain a mixed phase core and its size depends on the surface tension of the hadron-quark interface and the vector coupling between quarks. The repulsive vector interaction in the Nambu-Jona-Lasinio model can stiffen the equation of state of quark matter, and therefore delay the phase transition and increase the maximum mass of neutron stars.

In this article the analysis of the result of numerical simulations of pasta phases using algebraic topology methods is presented. These considerations suggest that some phases can be further split into subphases and therefore should be more refined in numerical simulations. The results presented in this article can also be used to relate the Euler characteristic from numerical simulations to the geometry of the phases. The Betti numbers are used as they provide finer characterization of the phases. It is also shown that different boundary conditions give different outcomes.

At TRIUMF, the TIGRESS Integrated Plunger device and its suite of ancillary detector systems have been implemented for charged-particle tagging and light-ion identification in coincidence with $\gamma$-ray spectroscopy for Doppler-shift lifetime studies and low-energy Coulomb excitation measurements. As a test of the device, the lifetime of the first $2^{+}$ excited state in ${}^{36}\mathrm{Ar}$ was measured from the $\gamma$-ray line shape of the $2_1^{+}\to 0_{\mathrm{g}.\mathrm{s}.}^{+}$ transition using the Doppler-shift attenuation technique following Coulomb excitation. The line-shape signatures, vital for precision lifetime measurements, were significantly improved by enhanced reaction-channel selectivity using a complementary approach of kinematic gating and digital rise-time discrimination of recoiling charged particles in a silicon PIN diode array. The lifetime was determined by comparisons between the data and simulated line shapes generated using our TIGRESS Coulomb excitation code as an input to the Lindhard method, which was then extended and included as a class in geant4. The model-independent lifetime result of $490\pm 50$ fs corresponds to a reduced quadrupole transition strength of $B(E2;2_1^{+}\to 0_{\mathrm{g}.\mathrm{s}.}^{+})=56\pm 6{\mathrm{e}}^2{\mathrm{fm}}^4$ and agrees well with previous intermediate energy Coulomb excitation measurements, thereby resolving reported discrepancies in the $2_1^{+}$ level lifetime in this self-conjugate nucleus.