Superdeformed excitations in ${}^{195}\mathrm{Pb}$ were populated via the ${}^{174}\mathrm{Yb}$(${}^{26}\mathrm{Mg}$,$5n$) reaction, and γ-ray spectroscopy measurements were made with Gammasphere. Analysis of the intensities of the discrete transitions between superdeformed states indicates that the decay out occurs from the favored band of the lowest signature pair. The quasicontinuous spectra associated with the decay of superdeformed bands in ${}^{195}\mathrm{Pb}$ have been extracted for both signatures. The onset of γ-ray intensity and the normalized γ-ray intensity of the quasicontinuum decay spectrum are used to set a lower bound of 2.5 MeV at $\sim 11\hslash$ for superdeformed excitation energy relative to normal deformed excitations in ${}^{195}\mathrm{Pb}$.

The dynamical appearance of scaling solutions in relativistic hydrodynamics is studied for boost-invariant, cylindrically symmetric systems. Such solutions reproduce key qualitative features of the blast-wave, Buda-Lund, and Cracow models, which in turn fit a broad set of data measured in ultrarelativistic heavy-ion collisions. Effects of a phase transition are taken into account by using a temperature-dependent speed of sound, inferred from a lattice QCD equation of state. The transverse flow may acquire the asymptotic Hubble form $r/t$ within short evolution times, 7–15 fm, only if an initial pre-equilibrium transverse flow is present. The precise amount of the requisite pre-equilibrium flow is anticorrelated with the initial value of the central temperature.

The hadron production in relativistic heavy ion collisions is well described by the quark combination model. The mixed ratios for various hadrons and the transverse momentum spectra for long-life hadrons are predicted and agree with recent Relativistic Heavy Ion Collider data. The production rates for the pentaquarks ${\Theta }^{+}$ and ${\Theta }^{*++}$ and the di-baryon $(\Omega \Omega ){}_{0^{+}}$ are estimated, neglecting the effect from the transition amplitude for constituent quarks to form an exotic state.

Phenomenologically, hydrodynamical calculations have been successful in describing global observables in ultrarelativistic heavy-ion collisions, which aim to observe the production of the quark-gluon plasma. On the other hand, theoretically, a lot of evidence that there exists a critical end point (CEP) in the phase diagram of the quantum chromodynamics has been accumulating recently. Nevertheless, so far, no equation of state with the CEP has been employed in hydrodynamical calculations. In this article, we construct the equation of state with the CEP on the basis of the universality hypothesis and show that the CEP acts as an attractor of isentropic trajectories. We also consider the time evolution in the case with the CEP and discuss how the CEP affects the final state observables, such as the correlation length, fluctuation, chemical freeze-out, kinetic freeze-out, and so on. Finally, we argue that the anomalously low kinetic freeze-out temperature at the Relativistic Heavy-Ion Collider at the Brookhaven National Laboratory suggests the possibility of the existence of the CEP.

We study the two-meson virtual cloud contribution to the self-energy of the $\mathrm{SU}(3)$ antidecuplet, to which the ${\Theta }^{+}$ pentaquark is assumed to belong. This is motivated by the large branching ratio of the $N(1710)$ decay into two pions and one nucleon. We derive effective Lagrangians that describe the $N(1710)$ decay into $N\pi \pi$ with two pions in s or p wave. We obtain increased binding for all members of the antidecuplet and a contribution to the mass splitting between states with different strangeness which is at least $20\%$ of the empirical one. We also provide predictions for three-body decays of the pentaquark antidecuplet.

Accurately calibrated effective field theories are used to compute atomic parity nonconserving (APNC) observables. Although accurately calibrated, these effective field theories predict a large spread in the neutron skin of heavy nuclei. Whereas the neutron skin is strongly correlated to numerous physical observables, in this contribution we focus on its impact on new physics through APNC observables. The addition of an isoscalar-isovector coupling constant to the effective Lagrangian generates a wide range of values for the neutron skin of heavy nuclei without compromising the success of the model in reproducing well-constrained nuclear observables. Earlier studies have suggested that the use of isotopic ratios of APNC observables may eliminate their sensitivity to atomic structure. This leaves nuclear structure uncertainties as the main impediment for identifying physics beyond the standard model. We establish that uncertainties in the neutron skin of heavy nuclei are at present too large to measure isotopic ratios to better than the 0.1% accuracy required to test the standard model. However, we argue that such uncertainties will be significantly reduced by the upcoming measurement of the neutron radius in ${}^{208}\mathrm{Pb}$ at the Jefferson Laboratory.

Radiative strength functions (RSFs) in ${}^{93-98}\mathrm{Mo}$ have been extracted using the $({}^3\mathrm{He},\alpha \gamma )$ and $({}^3\mathrm{He},{{}^3\mathrm{He}}^{\text{'}}\gamma )$ reactions. The RSFs are U shaped as function of γ energy with a minimum at around $E_{\gamma }=3\hspace{1em}\mathrm{MeV}$. The minimum values increase with neutron number because of the increase in the low-energy tail of the giant electric dipole resonance with nuclear deformation. The unexpected strong increase in strength below $E_{\gamma }=3\hspace{1em}\mathrm{MeV}$, here called soft pole, is established for all ${}^{93-98}\mathrm{Mo}$ isotopes. The soft pole is present at all initial excitation energies in the $5-8\text{−}\mathrm{MeV}$ region.

We study Fermi transitions and isospin mixing in an isotopic chain $({}^{70\text{−}78}\mathrm{Kr})$ considering various approximations that use the same Skyrme-Hartree-Fock single-particle basis. We study Coulomb effects as well as the effect of BCS and quasiparticle random phase approximation (QRPA) correlations. A measure of isospin mixing in the approximate ground state is defined by means of the expectation value of the isospin operator squared in $N=Z$ nuclei (which is generalized to $N\ne Z$ nuclei). Starting from a strict Hartree-Fock approach without Coulomb interaction, it is shown that the isospin breaking is negligible, on the order of a few per thousand for $(N-Z)=6$, increasing to a few percent with Coulomb interaction. Pairing correlations induce rather large isospin mixing and Fermi transitions of the forbidden type $({\beta }^{-}$ for $N\le Z$, and ${\beta }^{+}$ for $N\ge Z)$. The enhancement produced by BCS correlations is compensated to a large extent by QRPA correlations induced by isospin-conserving residual interactions that tend to restore isospin symmetry.

The convergence properties of a multiparticle-multihole (mp-mh) configuration mixing approach whose purpose is to describe ground state correlations in nuclei without particle-number and Pauli violations are investigated in the case of an exactly solvable pairing Hamiltonian. Two different truncation schemes are tested by looking at quantities as correlation energies and single-particle occupation probabilities. Results show that pairing correlations present in usual superfluid nuclei can be accurately described using up to 6-particle–6-hole excitations; the convergence is fast enough for us to envisage extensions to fully microscopic calculations.

The calculations for the neutrino absorption cross sections for supernova neutrinos in ${}^{56}\mathrm{Fe}$ have been done in the local density approximation (LDA) taking into account Pauli blocking and Fermi motion effects. The renormalization of weak transition strengths in the nuclear medium and the effect of Coulomb distortion of the final lepton are taken into account. The numerical results for the cross sections averaged over the Michel spectrum of neutrinos and various supernova neutrino spectra are presented and compared with other theoretical results.

We prove several inequalities using lowest-order effective field theory for nucleons which give an upper bound on the pressure of asymmetric nuclear matter and neutron matter. We prove two types of inequalities, one based on convexity and another derived from shifting an auxiliary field.

A relation connecting the spin dependence of the energies E(I$+$2) of the members of the rotational ground-state band with the E2 reduced transition probabilities $B(E2;(I+2){}_1\to I_1$) is derived based on the Bohr Hamiltonian. This relation generalizes the Grodzins relation from the $2_1^{+}$ state to all members of the ground-state band.

The differential cross sections for the $\gamma n\to {\pi }^{-}p$ and the $\gamma p\to {\pi }^{+}n$ processes were measured at Jefferson Lab. The photon energies ranged from 1.1 to 5.5 GeV, corresponding to center-of-mass energies from 1.7 to 3.4 GeV. The pion center-of-mass angles varied from ${50}^{°}$ to ${110}^{°}$. The ${\pi }^{-}$ and ${\pi }^{+}$ photoproduction data both exhibit a global scaling behavior at high energies and high transverse momenta, consistent with the constituent counting rule prediction and the existing ${\pi }^{+}$ data. The data suggest possible substructure of the scaling behavior, which might be oscillations around the scaling value. The data show an enhancement in the scaled cross section at center-of-mass energy near 2.2 GeV. The differential cross section ratios $[d\sigma /\mathit{dt}(\gamma n\to {\pi }^{-}p)/d\sigma /\mathit{dt}(\gamma p\to {\pi }^{+}n)]$ at high energies and high transverse momenta can be described by calculations based on one-hard-gluon-exchange diagrams.

Using an isospin- and momentum-dependent transport model we study the emission of free nucleons and nuclear radial flow in central heavy-ion collisions induced by high-energy radioactive beams. The midrapidity neutron/proton ratio and its transverse momentum dependence are found to be very sensitive to the high-density behavior of nuclear symmetry energy. The nuclear radial flow, however, depends only weakly on the symmetry energy.

In this article we study the enumeration of number (denoted as $D_I$) of spin I states for fermions in a single-j shell and bosons with spin l. We show that $D_I$ can be enumerated by the reduction from SU$(n+1)$ to SO(3). New regularities of $D_I$ are discerned. As an example of our new algorithm, we obtained analytical expressions of $D_I$ for four particles.

The even ${}^{52-56}\mathrm{Ti}$ isotopes have been studied with intermediate-energy Coulomb excitation and absolute $B(E2;0^{+}\to 2_1^{+})$ transition rates have been obtained. These data confirm the presence of a subshell closure at neutron number $N=32$ in neutron-rich nuclei above the doubly magic nucleus ${}^{48}\mathrm{Ca}$ and provide no direct evidence for the predicted $N=34$ closure. Large-scale shell model calculations with the most recent effective interactions are unable to reproduce the magnitude of the measured strengths in the semimagic Ti nuclei and their strong variation with neutron number.

We investigate the nuclear collective excitations of Wigner-Seitz cells containing nuclear clusters immersed in a gas of neutrons. This baryonic nonuniform system is specific to the structure of inner crust matter of neutron stars. The collective excitations are studied in the framework of a spherical Hartree-Fock-Bogoliubov $+$ quasiparticle random phase approximation, formulated in coordinate representation. The calculations are done for two representative Wigner-Seitz cells with baryonic density equal to 0.02 and $0.08\hspace{1em}{\mathrm{fm}}^{-3}$. It is shown that the excitations with low multipolarities are concentrated almost entirely in one strongly collective mode which exhausts a very large fraction of the energy-weighted sum rule. Since these collective modes are located at very low energies compared to the giant resonances in standard nuclei, they may affect significantly the specific heat of baryonic inner crust matter of neutron stars.

Semiperipheral collisions in the ${}^{124}\mathrm{Sn}+{}^{64}\mathrm{Ni}$ reaction at 35 MeV/nucleon were studied using the forward part of the Charged Heavy Ion Mass and Energy Resolving Array. Nearly completely determined ternary events involving projectilelike fragments (PLF), targetlike fragments (TLF), and intermediate mass fragments (IMF) were selected. A new method of studying the reaction mechanism, focusing on the analysis of the correlations between relative velocities in the IMF+PLF and IMF+TLF subsystems, is proposed. The relative velocity correlations provide information on the time sequence and time scale of the neck fragmentation processes leading to production of IMFs. It is shown that the majority of light IMFs are produced within 40–80 fm/c after the system starts to reseparate. Heavy IMFs are formed at times of about 120 fm/c or later and can be viewed as resulting from two-step (sequential) neck rupture processes.

We study the nonstrange baryon spectrum within a three-body theory that treats relativistically both the space and the spin variables. The relativistic effects of the spin are about one order of magnitude smaller than those due to the use of relativistic momentum variables. The relativistic treatment of the spin breaks the degenerancy that is present in the nonrelativistic model and in the model with only relativistic momentum variables.

A ${}^{14}\mathrm{C}({}^3\mathrm{He},t){}^{14}\mathrm{O}$ experiment was performed using a ${}^3\mathrm{He}$ beam with $E=140$ MeV/nucleon. The achieved resolution of 33 keV (full width at half maximum) for the small scattering angle spectrum allowed the determination of the widths of several levels up to an excitation energy of 11.5 MeV. The width of the $E_x=5.17\hspace{1em}\mathrm{MeV},J^{\pi }=1^{-}$ level was in good agreement with the known value, while for other states considerably improved or new results were obtained.