Full Faddeev-type calculations are performed for ${}^{11}\mathrm{Be}$ breakup on a proton target at 38.4, 100, and 200 MeV/u incident energies. The convergence of the multiple scattering expansion is investigated. The results are compared with those of other frameworks like distorted-wave impulse approximation that are based on an incomplete and truncated multiple scattering expansion.

The structure and $2\alpha +2p$ breakup of ${}^{10}\mathrm{C}$, the only known Brunnian nucleus, has been studied at 33.3 MeV/nucleon. The breakup kinematics were used to reconstruct the ${}^{10}\mathrm{C}$ → ${}^9\mathrm{B}$ $+p,$${}^9\mathrm{B}$ → ${}^8\mathrm{Be}$ $+p,$${}^8\mathrm{Be}$ $\to \alpha +\alpha$ and ${}^{10}\mathrm{C}$ → ${}^6\mathrm{Be}$ $+\alpha ,$${}^6\mathrm{Be}$ → ${}^5\mathrm{Li}$ $+p,$${}^5\mathrm{Li}$ $\to \alpha +p$ decay paths. Proton emission was seen to be favored. The decay of excited states at $E_x=4.20,5.31$, and 6.74 MeV was observed. The previously unobserved state at 4.20 MeV may correspond to a $J^{\pi }=0^{+}\alpha +2p+\alpha$ cluster structure.

In relativistic heavy-ion collisions, anisotropic collective flow is driven, event by event, by the initial eccentricity of the matter created in the nuclear overlap zone. Interpretation of the anisotropic flow data thus requires a detailed understanding of the effective initial source eccentricity of the event sample. In this paper, we investigate various ways of defining this effective eccentricity using the Monte Carlo Glauber (MCG) approach. In particular, we examine the participant eccentricity, which quantifies the eccentricity of the initial source shape by the major axes of the ellipse formed by the interaction points of the participating nucleons. We show that reasonable variation of the density parameters in the Glauber calculation, as well as variations in how matter production is modeled, do not significantly modify the already established behavior of the participant eccentricity as a function of collision centrality. Focusing on event-by-event fluctuations and correlations of the distributions of participating nucleons, we demonstrate that, depending on the achieved event-plane resolution, fluctuations in the elliptic flow magnitude $v_2$ lead to most measurements being sensitive to the root-mean-square rather than the mean of the $v_2$ distribution. Neglecting correlations among participants, we derive analytical expressions for the participant eccentricity cumulants as a function of the number of participating nucleons, $N_{\mathrm{part}}$, keeping nonnegligible contributions up to $\mathcal{O}(1/N_{\mathrm{part}}^3)$. We find that the derived expressions yield the same results as obtained from mixed-event MCG calculations which remove the correlations stemming from the nuclear collision process. Most importantly, we conclude from the comparison with MCG calculations that the fourth-order participant eccentricity cumulant does not approach the spatial anisotropy obtained assuming a smooth nuclear matter distribution. In particular, for the Cu+Cu system, these quantities deviate from each other by almost a factor of 2 over a wide range in centrality. This deviation reflects the essential role of participant spatial correlations in the interaction of two nuclei.

The possible coexistence and/or competition of kaon condensation with hyperons are investigated in hyperonic matter, where hyperons are mixed in the ground state of neutron-star matter. The formulation is based on the effective chiral Lagrangian for the kaon-baryon interaction and the nonrelativistic baryon-baryon interaction model. First, the onset condition of the $s$-wave kaon condensation realized from hyperonic matter is reexamined. It is shown that the usual assumption of the continuous phase transition is not always kept valid in the presence of the negatively charged hyperons (${\Sigma }^{-}$). Second, the equation of state (EOS) of the kaon-condensed phase in hyperonic matter is discussed. In the case of the stronger kaon-baryon attractive interaction, it is shown that a local energy minimum with respect to the baryon number density appears as a result of considerable softening of the EOS due to both kaon condensation and hyperon mixing and recovering of the stiffness of the EOS at very high densities. This result implies a possible existence of self-bound objects with kaon condensates on any scale from an atomic nucleus to a neutron star.

The contribution of the box and crossed two-pion-exchange diagrams to proton-proton scattering at ${90}_{\mathrm{c}.\mathrm{m}.}^{○}$ is calculated in the laboratory momentum range up to 12 GeV/$c$. Relativistic form factors related to the nucleon and pion size and representing the pion source distribution are included at each vertex of the pion-nucleon interaction. These form factors depend on the four-momenta of the exchanged pions and scattering nucleons. Feynman-diagram amplitudes calculated without form factors are checked against those derived from dispersion relations. In this comparison, it was observed that a very short-range part of the crossed diagram, neglected in dispersion-relation calculations of the two-pion-exchange nucleon-nucleon potential, gives a sizable contribution. In the Feynman-diagram calculation with form factors the agreement with measured spin-separated cross sections, as well as amplitudes in the lower part of the energy range considered, is better for pion-nucleon pseudovector vis à vis pseudoscalar coupling although potentially important corrections for inelastic effects are lacking. While strengths of the box and crossed diagrams are comparable for laboratory momenta below 2 GeV/$c$, the crossed diagram dominates for larger momenta, largely due to the kinematics of the crossed diagram allowing a smaller momentum transfer in the nucleon center of mass. An important contribution arises from the principal-value part of the integrals which is non-zero when form factors are included. The imaginary part of the amplitude arising from the form factor remains to be understood. It seems that the importance of the exchange of color singlets may extend higher in energy than expected.

We present a quasiclassical theory of α decay accompanied by bremsstrahlung with a special emphasis on the case of ${}^{210}\mathrm{Po}$, with the aim of finding a unified description that incorporates both the radiation during the tunneling through the Coulomb wall and the finite energy $E_{\gamma }$ of the radiated photon up to $E_{\gamma }~Q_{\alpha }/\sqrt{\eta }$, where $Q_{\alpha }$ is the α-decay $Q$-value and η is the Sommerfeld parameter. The corrections with respect to previous quasiclassical investigations are found to be substantial, and excellent agreement with a full quantum mechanical treatment is achieved. Furthermore, we find that a dipole-quadrupole interference significantly changes the $\alpha \text{−}\gamma$ angular correlation. We obtain good agreement between our theoretical predictions and experimental results.

Based on a Langevin equation coupled with a statistical decay model, we have studied the evaporation residue spin distribution of the nuclei ${}^{194}\mathrm{Pb}$, ${}^{200}\mathrm{Pb}$, ${}^{200}\mathrm{Pb}$, and ${}^{200}\mathrm{Os}$, and extracted a presaddle nuclear dissipation strength of $5\times {10}^{21}{\mathrm{s}}^{-1}$ by comparing our results with the measured spin distribution of ${}^{200}\mathrm{Pb}$ produced in the ${}^{16}\mathrm{O}+{}^{184}\mathrm{W}$ reaction. We find that with increasing isospin of the system, the sensitivity of the spin distribution to nuclear dissipation decreases substantially. Moreover, for ${}^{200}\mathrm{Os}$, this spin distribution is no longer sensitive to the nuclear dissipation. These results suggest that on the experimental side, to accurately obtain the information of presaddle dissipation strength by measuring the evaporation residue spin distribution, it is best to populate those systems with low isospin.

The breakdown of the $N=20$ magic number in the so-called island of inversion around ${}^{32}\mathrm{Mg}$ is well established. Recently developed large-scale shell-model calculations suggest a transitional region between normal- and intruder-dominated nuclear ground states, thus modifying the boundary of the island of inversion. In particular, a dramatic change in single-particle structure is predicted between the ground states of ${}^{30}\mathrm{Mg}$ and ${}^{32}\mathrm{Mg}$, with the latter consisting nearly purely of 2p-2h $N=20$ cross-shell configurations. Single-neutron knockout experiments on ${}^{30,32}\mathrm{Mg}$ projectiles have been performed. We report on a first direct observation of intruder configurations in the ground states of these very neutron-rich nuclei. Spectroscopic factors to low-lying negative-parity states in the knockout residues are deduced and compare well with shell-model predictions.

The half-life of the superallowed ${\beta }^{+}$ emitter ${}^{62}\mathrm{Ga}$ has been measured at TRIUMF's Isotope Separator and Accelerator facility using a fast-tape-transport system and $4\pi$ continuous-flow gas proportional counter to detect the positrons from the decay of ${}^{62}\mathrm{Ga}$ to the daughter ${}^{62}\mathrm{Zn}$. The result, $T_{1/2}=116.100\pm 0.025$ ms, represents the most precise measurement to date (0.022%) for any superallowed β-decay half-life. When combined with six previous measurements of the ${}^{62}\mathrm{Ga}$ half-life, a new world average of $T_{1/2}=116.121\pm 0.021$ ms is obtained. This new half-life measurement results in a 20% improvement in the precision of the ${}^{62}\mathrm{Ga}$ superallowed $\mathit{ft}$ value while reducing its mean by $0.9\sigma$ to $\mathit{ft}=3074.3(12)$ s. The impact of this half-life measurement on precision tests of the CVC hypothesis and isospin symmetry breaking corrections for $A⩾62$ superallowed decays is discussed.

Neutron capture nucleosynthesis in massive stars plays an important role in galactic chemical evolution as well as for the analysis of abundance patterns in very old metal-poor halo stars. The so-called weak $s$-process component, which is responsible for most of the $s$ abundances between Fe and Sr, turned out to be very sensitive to the stellar neutron capture cross sections in this mass region and, in particular, of isotopes near the seed distribution around Fe. Activation measurements in a quasistellar neutron spectrum corresponding to a thermal energy of $\mathit{kT}=25$ keV have been carried out on ${}^{58}\mathrm{Fe}$, ${}^{59}\mathrm{Co}$, ${}^{64}\mathrm{Ni}$, ${}^{63}\mathrm{Cu}$, and ${}^{65}\mathrm{Cu}$. By a series of repeated irradiations with different experimental conditions, uncertainties between 3.0% and 4.6% could be achieved, factors of 2 to 3 more accurate than previous data. Compared to previous measurements, severe discrepancies were found for ${}^{63,65}\mathrm{Cu}$. The consequences of these results have been studied by detailed model calculations for convective core He burning and convective shell C burning in massive stars.

The direct and semi-direct (DSD) components of the neutron capture cross sections are calculated for a series of tin isotopes by employing a single-particle potential (SPP) that gives a good reproduction of the known single-particle energies (SPEs) over a wide mass region. The results are compared with the Hauser-Feshbach (HF) contribution in the energy region of astrophysical interest. The calculated result shows that the HF component drops off rapidly for isotope ${}^{132}\mathrm{Sn}$ and toward more neutron-rich ones, whereas the DSD component decreases only smoothly and eventually becomes dominant. This result is consistent with those of previous studies, but the dependence of the DSD cross section on the target mass number is a feature of the present SPP that gives a smooth variation of SPEs. As a consequence, the direct portion of the DSD component gives the largest contribution to the total ($n,\gamma$) cross section for neutron-rich isotopes below a few MeV. Therefore, the direct capture process modifies the astrophysical ($n,\gamma$) reaction rates to a great extent. The semi-direct component, however, gives a negligible contribution to the astrophysical reaction rates, but its impact is significant above several MeV. The reason for the difference in isotopic dependence between the HF and DSD components is discussed, and its implication for $r$-process nucleosynthesis is given.

We derive relations between spin-dependent nuclear and nucleon $g_1$ and $g_2$ structure functions within the nuclear impulse approximation, which are valid at all $Q^2$, and in both the resonance and deep inelastic regions. We apply the formalism to the specific case of the deuteron, which is often used as a source of neutron structure information, and compare the size of the nuclear corrections calculated using exact kinematics and using approximations applicable at large $Q^2$.

We report the first calculations of nuclear properties near the drip lines using the spherical Hartree-Fock-Bogoliubov mean-field theory with a finite-range force supplemented by continuum and particle-number projection effects. Calculations were carried out in a basis made of the eigenstates of a Woods-Saxon potential computed in a box, thereby guaranteeing that continuum effects were properly taken into account. Projection of the self-consistent solutions on good particle number was carried out after variation, and an approximation of the variation after projection result was used. We give the position of the drip lines and examine neutron densities in neutron-rich nuclei. We discuss the sensitivity of nuclear observables upon continuum and particle-number restoration effects.

We present transverse momentum ($p_T$) spectra of charged hadrons measured in deuteron-gold and nucleon-gold collisions at $\sqrt{s_{{}_{\mathit{NN}}}}=200$ GeV for four centrality classes. Nucleon-gold collisions were selected by tagging events in which a spectator nucleon was observed in one of two forward rapidity detectors. The spectra and yields were investigated as a function of the number of binary nucleon-nucleon collisions, ν, suffered by deuteron nucleons. A comparison of charged particle yields to those in $p+p$ collisions show that yield per nucleon-nucleon collision saturates with ν for high momentum particles. We also present the charged hadron to neutral pion ratios as a function of $p_T$.

An analysis of inclusive pion production in proton-beryllium collisions at 6.4, 12.3, and 17.5 GeV/$c$ proton beam momentum has been performed. The data were taken by Experiment 910 at the Alternating Gradient Synchrotron at the Brookhaven National Laboratory. The differential ${\pi }^{+}$ and ${\pi }^{-}$ production cross sections ($d^2\sigma /\mathit{dpd}\Omega$) were measured up to 400 mrad in ${\theta }_{\pi }$ and up to 6 GeV/$c$ in $p_{\pi }$. The measured cross section was fit with a Sanford-Wang parametrization.

Strange quark matter could be found in the core of neutron stars or forming strange quark stars. As is well known, these astrophysical objects are endowed with strong magnetic fields that affect the microscopic properties of matter and modify the macroscopic properties of the system. In this article we study the role of a strong magnetic field in the thermodynamical properties of a magnetized degenerate strange quark gas, taking into account β-equilibrium and charge neutrality. Quarks and electrons interact with the magnetic field via their electric charges and anomalous magnetic moments. In contrast to the magnetic field value of ${10}^{19}$ G, obtained when anomalous magnetic moments are not taken into account, we find the upper bound $B\lesssim 8.6\times {10}^{17}$ G, for the stability of the system. A phase transition could be hidden for fields greater than this value.

The leading-order nucleon-nucleon ($\mathit{NN}$) potential derived from chiral perturbation theory consists of one-pion exchange plus short-distance contact interactions. We show that in the ${}^1{S}_0$ and ${}^3{S}_1\text{−}{}^3{D}_1$ channels, renormalization of the Lippmann-Schwinger equation for this potential can be achieved by performing one subtraction. This subtraction requires as its only input knowledge of the $\mathit{NN}$ scattering lengths. This procedure leads to a set of integral equations for the partial-wave $\mathit{NN}t$ matrix which gives cutoff-independent results for the corresponding $\mathit{NN}$ phase shifts. This reformulation of the $\mathit{NN}$ scattering equation offers practical advantages, because only observable quantities appear in the integral equation. The scattering equation may then be analytically continued to negative energies, from which information on bound-state energies and wave functions can be extracted.

On-line β-NMR measurements on nuclei oriented at low temperatures of the magnetic dipole moment of ${}^{71}\mathrm{Cu}$($N=42$) are reported, with the result $\mu$(${}^{71}\mathrm{Cu}$)$=+2.28(1)$ nuclear magneton (n.m.). The value shows a significant difference from $\mu$(${}^{67}\mathrm{Cu}$)$=+2.54(2)$ n.m., revealing asymmetry with respect to $N=40$. This effect presents a challenge to theoretical interpretation.