Neutron-rich isotopes in the $\mathit{sdpf}$ space with $Z⩽14$ require modifications to derived effective interactions to agree with experimental data away from stability. A quantitative justification is given for these modifications because of the weakly bound nature of model space orbits via a procedure using realistic radial wave functions and realistic $\mathit{NN}$ interactions. The long tail of the radial wave function for loosely bound single-particle orbits causes a reduction in the size of matrix elements involving those orbits, most notably for pairing matrix elements, resulting in a more condensed level spacing in shell-model calculations. Example calculations are shown for ${}^{36}\mathrm{Si}$ and ${}^{38}\mathrm{Si}$.

The two $\Delta I=1$ bands in ${}^{111}\mathrm{In}$, built upon the 3461.0 and 4931.8 keV states, have been studied. The bands were populated in the reaction ${}^{100}\mathrm{Mo}$(${}^{19}\mathrm{F}$,$\hspace{0.5em}\alpha 4n\gamma$) at a beam energy of 105 MeV. Mean lifetimes of nine states, four in the first and five in the second band, have been determined for the first time from Doppler shift attenuation data. The deduced $B$($M$1) rates and their behavior as a function of level spin support the interpretation of these bands within the framework of the shears mechanism. The geometrical model of Machiavelli et al. has been used to derive the effective gyromagnetic ratios for the two bands.

Different steps leading to the new functional for pairing based on natural orbitals and occupancies proposed earlier [D. Lacroix and G. Hupin, Phys. Rev. B 82, 144509 (2010)] are carefully analyzed. Properties of quasiparticle states projected onto good particle numbers are first reviewed. These properties are used to (i) prove the existence of such a functional, (ii) provide an explicit functional through a $1/N$ expansion starting from the BCS approach, and (iii) give a compact form of the functional summing up all orders in the expansion. The functional is benchmarked in the case of the picket-fence pairing Hamiltonian where even and odd systems are studied, using the blocking technique, at various particle numbers and coupling strengths, with uniform and random single-particle level spacing. In all cases, very good agreement is found, with a deviation of $<$1% compared to the exact energy.

Pseudorapidity distributions of charged particles emitted in $\text{Au}+\text{Au}$, $\text{Cu}+\text{Cu}$, $d+\text{Au}$, and $p+p$ collisions over a wide energy range have been measured using the PHOBOS detector at the BNL Relativistic Heavy-Ion Collider (RHIC). The centrality dependence of both the charged particle distributions and the multiplicity at midrapidity were measured. Pseudorapidity distributions of charged particles emitted with $\left|\eta \right|<5.4$, which account for between 95% and 99% of the total charged-particle emission associated with collision participants, are presented for different collision centralities. Both the midrapidity density ${\mathit{dN}}_{\text{ch}}/d\eta$ and the total charged-particle multiplicity $N_{\text{ch}}$ are found to factorize into a product of independent functions of collision energy, $\sqrt{s_{{}_{\mathit{NN}}}}$, and centrality given in terms of the number of nucleons participating in the collision, $N_{\text{part}}$. The total charged particle multiplicity, observed in these experiments and those at lower energies, assumes a linear dependence of $(\ln s_{{}_{\mathit{NN}}}){}^2$ over the full range of collision energy of $\sqrt{s_{{}_{\mathit{NN}}}}=2.7$–200 GeV.

The idea of glue clusters, i.e., short-range correlations in the quark-gluon plasma close to freeze-out, is used to estimate the width of balance functions in momentum space. A good agreement is found with the recent measurements of the STAR Collaboration for central Au-Au collisions.

Recent cross-section data for the reaction $\gamma +p\to K^{+}+\Lambda$ are examined for evidence of scaling in both the low-$t$ Regge domain and in the high-$\sqrt{s}$ and $-t$ domain where constituent counting may apply. It is shown that the reaction does scale in both regimes. At large center-of-mass angles, $s^{-7}$ scaling appears to hold at essentially all $-t$ but with angle-dependent oscillations. The scaled data show particularly strong evidence for $s$-channel resonances for $-t$ below 2 GeV${}^2$ and for $W$ below about 2.3 GeV. The dominant contributions are consistent with an $N^{*}$$S_{11}$ resonance at 1690 MeV, a $P_{13}$ resonance at 1920 MeV, and a $D_{13}$ resonance at 2100 MeV, which interfere to give the observed strong angular dependence.

We present a Regge model for pion photoproduction which is basically free of parameters within the framework of the $s$-channel helicity amplitude. For completeness we take into account axial mesons $a_1(1260)$, $b_1(1235)$ and tensor meson $a_2(1320)$ in addition to the primary $\pi +\rho$ exchanges for charged pion photoproduction, while the axial meson $h_1(1170)$ exchange is added to the model of $\omega +{\rho }^0+b_1$ exchanges for the neutral case. The present model deals for the first time with the $a_2$ and $h_1$ Regge poles in the $s$-channel helicity amplitude. For model independence, we use coupling constants of all exchanged mesons determined from empirical decay widths or from the SU(3) relations together with consistency check with existing estimates that are widely accepted in other reaction processes. Based on these coupling constants the simultaneous description of four photoproduction channels is given. Within the Regge regime, $s\gg 4M^2$ and $-t<2$ GeV${}^2$, cross sections and spin polarization asymmetries at various photon energies are analyzed and results are obtained in better agreement with experimental data without referring to any fitting procedure. The model confirms dominance of the nucleon Born term in the sharp rise of the charged pion cross section at very forward angles, while dominance of the $\omega$ exchange with the nonsense wrong signature zero leads to the deep dip in the neutral pion cross section. In contrast to existing models, however, our model for the charged pion case shows quite a different production mechanism due to the crucial role of the tensor meson $a_2$ exchange in the cross section and spin polarization asymmetries. Also the axial meson $b_1$ exchange is found to give a sizable contribution to the photon polarization asymmetry. In the neutral case, the role of the $b_1$ is not significant, but the isoscalar $h_1$ exchange gives an important contribution to the dip-generating mechanism in the photon polarization, showing the isoscalar nature of the process with the $\omega$. These findings demonstrate validity of the present model with the prompt use of the tensor meson $a_2$ and axial meson $h_1$ for a wider application.

Relativistic mean-field theory with parameter set FSUGold that includes the isoscalar-isovector cross interaction term is extended to study the properties of neutron star matter in $\beta$ equilibrium by including hyperons. The influence of the attractive and repulsive $\Sigma$ potential on the properties of neutron star matter and the maximum mass of neutron stars is examined. We also investigate the equations of state for pure neutron matter and for nonstrange hadronic matter for comparison. For a pure neutron star, the maximum mass is about 1.8$M_{\text{sun}}$, while for a strange (nonstrange) hadronic star in $\beta$ equilibrium, the maximum mass is around 1.35$M_{\text{sun}}$ (1.7$M_{\text{sun}}$).

Critical examination of the experimental data from ${}^{156}\mathrm{Nd}$ and ${}^{156}\mathrm{Pm}$ $\beta$ decays and the observed location of relevant neutron and proton orbitals in the neighboring odd-$A$ isotones and isotopes, taken together with the low-lying two-quasiparticle (2qp) structures expected in ${}^{156}\mathrm{Pm}$ from the rotor-particle model, lead to the conclusion that a consistent description of all the available data is achieved with the $I^{\pi }=4^{+}$ spin-parity assignment to the $26.7s\hspace{0.5em}{}^{156}$Pm ground state (g.s.) and assignment of $I^{\pi }=1^{+}$ to its 150.3-keV isomer with the 2qp configuration $4_{\text{g.s.}}^{+}\{p_o:5/2[532\uparrow ]\pm n_o:3/2[521\uparrow ]\}{1}_{150}^{+}$. In the process, a two-neutron configuration is also suggested for the 1509-keV $4^{+}$ level in the daughter nucleus ${}^{156}\mathrm{Sm}$. The present analysis reiterates the important question of whether the $\beta$-decay $\log \hspace{0.5em}\text{ft}$ value, by itself, can be employed to deduce the relative parity of the $\beta$-connected states.

In the present work, the ${}^{197}\mathrm{Au}$($n,2n$) reaction cross section is experimentally determined relative to the ${}^{27}\mathrm{Al}$($n,\alpha$)${}^{24}\mathrm{Na}$ reaction at incident neutron energies of 9.0–10.5 MeV by means of the activation technique. The quasimonoenergetic fast neutron beam was produced via the ${}^2\mathrm{H}$($d,n$)${}^3\mathrm{He}$ reaction at the 5.5-MV Tandem Van de Graaff accelerator at the National Centre of Scientific Research (NCSR) “Demokritos” and was studied to determine the contribution of background “parasitic” neutrons using the multiple foil activation technique and the SULSA unfolding code. The cross sections for the population of the second isomeric state (${12}^{-}$) of ${}^{196}\mathrm{Au}$ and the sum of the ground ($2^{-}$) and first isomeric state ($5^{-}$) population cross sections were independently determined. Auxiliary Monte Carlo simulations were performed with the MCNP code. Theoretical calculations of the above cross sections in the 8–25 MeV region were carried out with the use of the STAPRE-F, EMPIRE, and TALYS codes, which were also compared in their implementation of the generalized superfluid model. The theoretical results are compared with previous work in the same mass region, and the strong dependence on the level scheme of the nuclei involved was revealed.

We examine two recent effective shell model interactions, JUN45 and JJ4B, that have been proposed for use in the $f_{5/2},p_{3/2},p_{1/2},g_{9/2}$ model space for both protons and neutrons. We calculate a number of quantities that did not enter into the fits undertaken to fix the parameters of both interactions. In particular we consider the static quadrupole moments ($Q$’s) of excited states of the even-even ${}^{70-76}\mathrm{Ge}$ isotopes, as well as the $B(E2)$ values in these nuclei. (We previously studied ${}^{70}\mathrm{Zn}$ isotopes using JJ4B.) Some striking disagreements between the JUN45 predictions and the experimental results had already been noted for the quadrupole moments of the $2_1^{+}$ states, $Q(2_1^{+}$)’s, of these nuclei. We investigate whether these discrepancies also occur for the JJ4B interaction. Subsequently, we also apply both interactions to calculate the $Q$’s of some more highly excited states and compare the two sets of predictions regarding the nature of the nuclear states under consideration. We seek to understand the measured signs of the $Q(2_1^{+}$)’s in the isotopic Ge chain by looking at a simple single-$J$ shell model and also at the collective vibrational and rotational pictures.

We calculated neutrino reactions on ${}^{40}\mathrm{Ar}$ for detecting core-collapsing supernovae (SNe) neutrinos. The nucleus was originally exploited to identify the solar neutrino emitted from ${}^8\mathrm{B}$ produced in pp chains on the Sun. With the higher energy neutrinos emitted from the core-collapsing SNe, contributions from higher multipole transitions, as well as from the Gamow-Teller and Fermi transitions, are shown to be important ingredients for understanding reactions induced by the SN neutrino. Moreover, higher excited states beyond a few states known in experiment diminish significantly the expected large difference between the cross sections of ${\nu }_e$ and ${\mathrm{\nu ̄}}_e$ reactions on ${}^{40}\mathrm{Ar}$, which difference is anticipated because of the large Q value in the ${\mathrm{\nu ̄}}_e$ reaction. The reduction is shown to lead to a difference between them of only a factor of 2.

The $N/Z$ dependence of projectile fragmentation at relativistic energies has been studied with the ALADIN forward spectrometer at the GSI Schwerionen Synchrotron (SIS). Stable and radioactive Sn and La beams with an incident energy of 600 MeV per nucleon have been used in order to explore a wide range of isotopic compositions. For the interpretation of the data, calculations with the statistical multifragmentation model for a properly chosen ensemble of excited sources were performed. The parameters of the ensemble, representing the variety of excited spectator nuclei expected in a participant-spectator scenario, are determined empirically by searching for an optimum reproduction of the measured fragment-charge distributions and correlations. An overall very good agreement is obtained. The possible modification of the liquid-drop parameters of the fragment description in the hot freeze-out environment is studied, and a significant reduction of the symmetry-term coefficient is found necessary to reproduce the mean neutron-to-proton ratios $\langle N\rangle /Z$ and the isoscaling parameters of $Z⩽10$ fragments. The calculations are, furthermore, used to address open questions regarding the modification of the surface-term coefficient at freeze-out, the $N/Z$ dependence of the nuclear caloric curve, and the isotopic evolution of the spectator system between its formation during the initial cascade stage of the reaction and its subsequent breakup.

The probability of $\alpha$-particle emission for some recently observed superheavy nuclei (SHN) are investigated. The $\alpha$-decay half-lives of SHN are calculated in a quantum tunneling model with density-dependent M3Y (DDM3Y) effective nuclear interaction using theoretical and measured $Q_{\alpha }$ values. We determine the density distribution of $\alpha$ and daughter nuclei from the relativistic mean-field (RMF) theory using FSUGold force, NL3, and TM1 parameter sets. The double-folded nuclear potential is numerically calculated in a more microscopic manner using these density distributions. The estimated values of $\alpha$-decay half-lives are in good agreement with the recent data. We compare our results with recently detected $\alpha$-decay chains from a new element with atomic number $Z=117$ reported by the Joint Institute for Nuclear Research, Dubna. Finally, we determine the half-lives of superheavy elements with $Z=108$–120 and neutron number $N=152$–190 to explore the long-standing predictions of the existence of an “island of stability” due to possible spherical proton ($Z~114$) and neutron ($N~184$) shell closures.

We performed fluctuation analysis by means of the local scaling dimension for the strength function of the isoscalar (IS) giant quadrupole resonance (GQR) in ${}^{208}\mathrm{Pb}$ where the strength function is obtained by the shell model calculation including 1p1h and 2p2h configurations. It is found that at almost all energy scales, fluctuation of the strength function obeys the Gaussian orthogonal ensemble (GOE) random matrix theory limit. This is contrasted with the results for the GQR in ${}^{40}\mathrm{Ca}$, where at the intermediate energy scale of about 1.7 MeV, a deviation from the GOE limit was detected. It is found that the physical origin for this different behavior of the local scaling dimension is ascribed to the difference in the properties of the damping process.

The parametric resonance enhancement of the phase of neutrons due to non-Newtonian anomalous gravitation is considered. The existence of such resonances is confirmed by numerical calculations. A possible experimental scheme for observing this effect is discussed based on an existing neutron interferometer design.

We present a microscopic calculation of spectroscopic factors for neutron and proton removal from ${}^{24}\mathrm{O}$ using the coupled-cluster method and a state-of-the-art chiral nucleon-nucleon interaction at next-to-next-to-next-to-leading order. To account for the coupling to the scattering continuum we use a Berggren single-particle basis that treats bound, resonant, and continuum states on an equal footing. We report neutron removal spectroscopic factors for the ${}^{23}\mathrm{O}$ states $J^{\pi }=1/2^{+}$, $5/2^{+}$, $3/2^{-}$, and $1/2^{-}$ and proton removal spectroscopic factors for the ${}^{23}\mathrm{N}$ states $1/2^{-}$ and $3/2^{-}$. Our calculations support the accumulated experimental evidence that ${}^{24}\mathrm{O}$ is a closed-shell nucleus.

Earlier data for the reaction ${}^{13}\mathrm{C}$(t,p) have been analyzed to extract widths for several states of ${}^{15}\mathrm{C}$. Results affect predictions of widths in ${}^{15}\mathrm{F}$.

A theoretical framework of coupled-channels antisymmetrized molecular dynamics that describes the multistrangeness system with mixing between different baryon species is developed and applied to ${}_{\mathrm{\Lambda }}^{12}\mathrm{C}$ and ${}_{\mathrm{\Xi }}^{12}\mathrm{Be}$. By introducing a minor modification to the YN G-matrix interaction derived from the Nijmegen model-D, the low-lying level structure and production cross section of ${}_{\mathrm{\Lambda }}^{12}\mathrm{C}$ are reasonably described. It is found that the low-lying states of ${}_{\mathrm{\Xi }}^{12}\mathrm{Be}$ are dominated by the ${}^{11}\mathrm{B}\otimes {\mathrm{\Xi }}^{-}$ channel and their order strongly depends on $\mathrm{\Xi }N$ effective interactions used in the calculation. The calculated peak position of the production cross section depends on the $\mathrm{\Xi }N$ effective interaction and the magnitude of spin-flip and non-spin-flip cross sections of $K^{-}p\to K^{+}{\mathrm{\Xi }}^{-}$ elemental processes. We suggest that the ${}^{12}\mathrm{C}(K^{-},K^{+}){}_{\mathrm{\Xi }}^{12}\mathrm{Be}$ reaction possibly provides us information about the $\mathrm{\Xi }N$ interaction.

Excited states in the ${}^{99}\mathrm{Pd}$ nucleus populated in the ${}^{75}\mathrm{As}$(${}^{28}\mathrm{Si}$, p3n) fusion-evaporation reaction at $E_{\mathrm{lab}}$$=$120 MeV have been investigated through in-beam $\gamma$-ray spectroscopic techniques using an array of Compton-suppressed clover detectors. The level scheme is established up to excitation energy $~$$11.5$ MeV and spin $~$$25\hslash$ with the addition of about 60 new transitions. The level structures observed in ${}^{99}\mathrm{Pd}$ have been interpreted in the framework of a microscopic theory based on the deformed Hartree-Fock and angular momentum projection techniques. Band structures at lower spins are based on the low-$\Omega$ $\nu g_{7/2}$ and $\nu d_{5/2}$ orbitals, and those at higher spins are reproduced for the $\pi (g_{9/2}){}^5\otimes \pi (g_{7/2})\otimes \nu (g_{7/2}){}^2\otimes \nu (h_{11/2}){}^2\otimes \nu (g_{9/2}){}^{-1}$ and $\pi (g_{9/2}){}^6\otimes \nu (g_{9/2}){}^{10}\otimes \nu (g_{7/2}){}^2\otimes \nu (h_{11/2})$ configurations. The octupole correlations in ${}^{99}\mathrm{Pd}$ have been inferred from new interband $E1$ transitions linking the $\Delta I=1$ states of the bands based on the $\nu h_{11/2}$ and $\nu d_{5/2}$ orbitals ($\Delta l=3$, $\Delta j=3$, and $\Delta \pi =-1$) with the deduced $B(E1)$ values $~$${10}^{-6}$ W.u.